f1669e7975
* defs.h: Define new ptrace constants unconditionally. * strace.c (detach): Fix comment. (trace): Remove now unnecessary "if USE_SEIZE". Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
2336 lines
58 KiB
C
2336 lines
58 KiB
C
/*
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* Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
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* Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
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* Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
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* Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "defs.h"
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#include <stdarg.h>
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#include <sys/param.h>
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#include <fcntl.h>
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#include <sys/resource.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <pwd.h>
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#include <grp.h>
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#include <dirent.h>
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#include <sys/utsname.h>
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#ifdef HAVE_PRCTL
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# include <sys/prctl.h>
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#endif
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#if defined(IA64)
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# include <asm/ptrace_offsets.h>
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#endif
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/* In some libc, these aren't declared. Do it ourself: */
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extern char **environ;
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extern int optind;
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extern char *optarg;
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#if defined __NR_tkill
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# define my_tkill(tid, sig) syscall(__NR_tkill, (tid), (sig))
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#else
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/* kill() may choose arbitrarily the target task of the process group
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while we later wait on a that specific TID. PID process waits become
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TID task specific waits for a process under ptrace(2). */
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# warning "tkill(2) not available, risk of strace hangs!"
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# define my_tkill(tid, sig) kill((tid), (sig))
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#endif
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/* Glue for systems without a MMU that cannot provide fork() */
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#if !defined(HAVE_FORK)
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# undef NOMMU_SYSTEM
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# define NOMMU_SYSTEM 1
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#endif
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#if NOMMU_SYSTEM
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# define fork() vfork()
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#endif
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cflag_t cflag = CFLAG_NONE;
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unsigned int followfork = 0;
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unsigned int ptrace_setoptions = 0;
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unsigned int xflag = 0;
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bool need_fork_exec_workarounds = 0;
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bool debug_flag = 0;
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bool Tflag = 0;
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unsigned int qflag = 0;
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/* Which WSTOPSIG(status) value marks syscall traps? */
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static unsigned int syscall_trap_sig = SIGTRAP;
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static unsigned int tflag = 0;
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static bool iflag = 0;
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static bool rflag = 0;
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static bool print_pid_pfx = 0;
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/* -I n */
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enum {
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INTR_NOT_SET = 0,
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INTR_ANYWHERE = 1, /* don't block/ignore any signals */
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INTR_WHILE_WAIT = 2, /* block fatal signals while decoding syscall. default */
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INTR_NEVER = 3, /* block fatal signals. default if '-o FILE PROG' */
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INTR_BLOCK_TSTP_TOO = 4, /* block fatal signals and SIGTSTP (^Z) */
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NUM_INTR_OPTS
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};
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static int opt_intr;
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/* We play with signal mask only if this mode is active: */
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#define interactive (opt_intr == INTR_WHILE_WAIT)
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/*
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* daemonized_tracer supports -D option.
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* With this option, strace forks twice.
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* Unlike normal case, with -D *grandparent* process exec's,
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* becoming a traced process. Child exits (this prevents traced process
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* from having children it doesn't expect to have), and grandchild
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* attaches to grandparent similarly to strace -p PID.
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* This allows for more transparent interaction in cases
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* when process and its parent are communicating via signals,
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* wait() etc. Without -D, strace process gets lodged in between,
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* disrupting parent<->child link.
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*/
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static bool daemonized_tracer = 0;
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#if USE_SEIZE
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static int post_attach_sigstop = TCB_IGNORE_ONE_SIGSTOP;
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# define use_seize (post_attach_sigstop == 0)
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#else
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# define post_attach_sigstop TCB_IGNORE_ONE_SIGSTOP
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# define use_seize 0
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#endif
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/* Sometimes we want to print only succeeding syscalls. */
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bool not_failing_only = 0;
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/* Show path associated with fd arguments */
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bool show_fd_path = 0;
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static bool detach_on_execve = 0;
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/* Are we "strace PROG" and need to skip detach on first execve? */
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static bool skip_one_b_execve = 0;
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/* Are we "strace PROG" and need to hide everything until execve? */
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bool hide_log_until_execve = 0;
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static int exit_code = 0;
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static int strace_child = 0;
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static int strace_tracer_pid = 0;
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static char *username = NULL;
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static uid_t run_uid;
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static gid_t run_gid;
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unsigned int max_strlen = DEFAULT_STRLEN;
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static int acolumn = DEFAULT_ACOLUMN;
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static char *acolumn_spaces;
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static char *outfname = NULL;
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/* If -ff, points to stderr. Else, it's our common output log */
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static FILE *shared_log;
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struct tcb *printing_tcp = NULL;
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static struct tcb *current_tcp;
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static struct tcb **tcbtab;
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static unsigned int nprocs, tcbtabsize;
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static const char *progname;
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unsigned os_release; /* generated from uname()'s u.release */
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static int detach(struct tcb *tcp);
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static int trace(void);
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static void cleanup(void);
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static void interrupt(int sig);
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static sigset_t empty_set, blocked_set;
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#ifdef HAVE_SIG_ATOMIC_T
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static volatile sig_atomic_t interrupted;
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#else
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static volatile int interrupted;
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#endif
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#ifndef HAVE_STRERROR
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#if !HAVE_DECL_SYS_ERRLIST
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extern int sys_nerr;
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extern char *sys_errlist[];
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#endif
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const char *
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strerror(int err_no)
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{
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static char buf[sizeof("Unknown error %d") + sizeof(int)*3];
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if (err_no < 1 || err_no >= sys_nerr) {
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sprintf(buf, "Unknown error %d", err_no);
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return buf;
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}
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return sys_errlist[err_no];
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}
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#endif /* HAVE_STERRROR */
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static void
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usage(FILE *ofp, int exitval)
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{
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fprintf(ofp, "\
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usage: strace [-CdffhiqrtttTvVxxy] [-I n] [-e expr]...\n\
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[-a column] [-o file] [-s strsize] [-P path]...\n\
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-p pid... / [-D] [-E var=val]... [-u username] PROG [ARGS]\n\
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or: strace -c[df] [-I n] [-e expr]... [-O overhead] [-S sortby]\n\
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-p pid... / [-D] [-E var=val]... [-u username] PROG [ARGS]\n\
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-c -- count time, calls, and errors for each syscall and report summary\n\
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-C -- like -c but also print regular output\n\
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-d -- enable debug output to stderr\n\
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-D -- run tracer process as a detached grandchild, not as parent\n\
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-f -- follow forks, -ff -- with output into separate files\n\
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-i -- print instruction pointer at time of syscall\n\
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-q -- suppress messages about attaching, detaching, etc.\n\
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-r -- print relative timestamp, -t -- absolute timestamp, -tt -- with usecs\n\
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-T -- print time spent in each syscall\n\
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-v -- verbose mode: print unabbreviated argv, stat, termios, etc. args\n\
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-x -- print non-ascii strings in hex, -xx -- print all strings in hex\n\
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-y -- print paths associated with file descriptor arguments\n\
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-h -- print help message, -V -- print version\n\
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-a column -- alignment COLUMN for printing syscall results (default %d)\n\
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-b execve -- detach on this syscall\n\
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-e expr -- a qualifying expression: option=[!]all or option=[!]val1[,val2]...\n\
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options: trace, abbrev, verbose, raw, signal, read, write\n\
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-I interruptible --\n\
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1: no signals are blocked\n\
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2: fatal signals are blocked while decoding syscall (default)\n\
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3: fatal signals are always blocked (default if '-o FILE PROG')\n\
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4: fatal signals and SIGTSTP (^Z) are always blocked\n\
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(useful to make 'strace -o FILE PROG' not stop on ^Z)\n\
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-o file -- send trace output to FILE instead of stderr\n\
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-O overhead -- set overhead for tracing syscalls to OVERHEAD usecs\n\
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-p pid -- trace process with process id PID, may be repeated\n\
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-s strsize -- limit length of print strings to STRSIZE chars (default %d)\n\
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-S sortby -- sort syscall counts by: time, calls, name, nothing (default %s)\n\
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-u username -- run command as username handling setuid and/or setgid\n\
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-E var=val -- put var=val in the environment for command\n\
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-E var -- remove var from the environment for command\n\
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-P path -- trace accesses to path\n\
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"
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/* ancient, no one should use it
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-F -- attempt to follow vforks (deprecated, use -f)\n\
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*/
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/* this is broken, so don't document it
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-z -- print only succeeding syscalls\n\
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*/
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, DEFAULT_ACOLUMN, DEFAULT_STRLEN, DEFAULT_SORTBY);
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exit(exitval);
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}
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static void die(void) __attribute__ ((noreturn));
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static void die(void)
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{
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if (strace_tracer_pid == getpid()) {
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cflag = 0;
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cleanup();
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}
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exit(1);
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}
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static void verror_msg(int err_no, const char *fmt, va_list p)
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{
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char *msg;
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fflush(NULL);
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/* We want to print entire message with single fprintf to ensure
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* message integrity if stderr is shared with other programs.
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* Thus we use vasprintf + single fprintf.
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*/
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msg = NULL;
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if (vasprintf(&msg, fmt, p) >= 0) {
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if (err_no)
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fprintf(stderr, "%s: %s: %s\n", progname, msg, strerror(err_no));
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else
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fprintf(stderr, "%s: %s\n", progname, msg);
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free(msg);
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} else {
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/* malloc in vasprintf failed, try it without malloc */
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fprintf(stderr, "%s: ", progname);
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vfprintf(stderr, fmt, p);
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if (err_no)
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fprintf(stderr, ": %s\n", strerror(err_no));
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else
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putc('\n', stderr);
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}
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/* We don't switch stderr to buffered, thus fprintf(stderr)
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* always flushes its output and this is not necessary: */
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/* fflush(stderr); */
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}
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void error_msg(const char *fmt, ...)
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{
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va_list p;
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va_start(p, fmt);
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verror_msg(0, fmt, p);
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va_end(p);
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}
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void error_msg_and_die(const char *fmt, ...)
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{
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va_list p;
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va_start(p, fmt);
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verror_msg(0, fmt, p);
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die();
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}
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void perror_msg(const char *fmt, ...)
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{
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va_list p;
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va_start(p, fmt);
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verror_msg(errno, fmt, p);
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va_end(p);
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}
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void perror_msg_and_die(const char *fmt, ...)
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{
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va_list p;
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va_start(p, fmt);
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verror_msg(errno, fmt, p);
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die();
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}
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void die_out_of_memory(void)
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{
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static bool recursed = 0;
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if (recursed)
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exit(1);
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recursed = 1;
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error_msg_and_die("Out of memory");
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}
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static void
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error_opt_arg(int opt, const char *arg)
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{
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error_msg_and_die("Invalid -%c argument: '%s'", opt, arg);
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}
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#if USE_SEIZE
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static int
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ptrace_attach_or_seize(int pid)
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{
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int r;
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if (!use_seize)
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return ptrace(PTRACE_ATTACH, pid, 0, 0);
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r = ptrace(PTRACE_SEIZE, pid, 0, 0);
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if (r)
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return r;
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r = ptrace(PTRACE_INTERRUPT, pid, 0, 0);
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return r;
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}
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#else
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# define ptrace_attach_or_seize(pid) ptrace(PTRACE_ATTACH, (pid), 0, 0)
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#endif
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/*
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* Used when we want to unblock stopped traced process.
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* Should be only used with PTRACE_CONT, PTRACE_DETACH and PTRACE_SYSCALL.
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* Returns 0 on success or if error was ESRCH
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* (presumably process was killed while we talk to it).
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* Otherwise prints error message and returns -1.
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*/
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static int
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ptrace_restart(int op, struct tcb *tcp, int sig)
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{
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int err;
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const char *msg;
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errno = 0;
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ptrace(op, tcp->pid, (void *) 0, (long) sig);
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err = errno;
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if (!err)
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return 0;
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msg = "SYSCALL";
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if (op == PTRACE_CONT)
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msg = "CONT";
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if (op == PTRACE_DETACH)
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msg = "DETACH";
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#ifdef PTRACE_LISTEN
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if (op == PTRACE_LISTEN)
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msg = "LISTEN";
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#endif
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/*
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* Why curcol != 0? Otherwise sometimes we get this:
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*
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* 10252 kill(10253, SIGKILL) = 0
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* <ptrace(SYSCALL,10252):No such process>10253 ...next decode...
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*
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* 10252 died after we retrieved syscall exit data,
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* but before we tried to restart it. Log looks ugly.
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*/
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if (current_tcp && current_tcp->curcol != 0) {
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tprintf(" <ptrace(%s):%s>\n", msg, strerror(err));
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line_ended();
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}
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if (err == ESRCH)
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return 0;
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errno = err;
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perror_msg("ptrace(PTRACE_%s,pid:%d,sig:%d)", msg, tcp->pid, sig);
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return -1;
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}
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static void
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set_cloexec_flag(int fd)
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{
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int flags, newflags;
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flags = fcntl(fd, F_GETFD);
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if (flags < 0) {
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/* Can happen only if fd is bad.
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* Should never happen: if it does, we have a bug
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* in the caller. Therefore we just abort
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* instead of propagating the error.
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*/
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perror_msg_and_die("fcntl(%d, F_GETFD)", fd);
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}
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newflags = flags | FD_CLOEXEC;
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if (flags == newflags)
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return;
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fcntl(fd, F_SETFD, newflags); /* never fails */
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}
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static void kill_save_errno(pid_t pid, int sig)
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{
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int saved_errno = errno;
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(void) kill(pid, sig);
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errno = saved_errno;
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}
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|
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/*
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* When strace is setuid executable, we have to swap uids
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* before and after filesystem and process management operations.
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*/
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static void
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swap_uid(void)
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{
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int euid = geteuid(), uid = getuid();
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if (euid != uid && setreuid(euid, uid) < 0) {
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perror_msg_and_die("setreuid");
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}
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}
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|
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#if _LFS64_LARGEFILE
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# define fopen_for_output fopen64
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# define struct_stat struct stat64
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# define stat_file stat64
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# define struct_dirent struct dirent64
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# define read_dir readdir64
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# define struct_rlimit struct rlimit64
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# define set_rlimit setrlimit64
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#else
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# define fopen_for_output fopen
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|
# define struct_stat struct stat
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# define stat_file stat
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# define struct_dirent struct dirent
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|
# define read_dir readdir
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|
# define struct_rlimit struct rlimit
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# define set_rlimit setrlimit
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#endif
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static FILE *
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strace_fopen(const char *path)
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{
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FILE *fp;
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swap_uid();
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fp = fopen_for_output(path, "w");
|
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if (!fp)
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perror_msg_and_die("Can't fopen '%s'", path);
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swap_uid();
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set_cloexec_flag(fileno(fp));
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return fp;
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}
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|
|
static int popen_pid = 0;
|
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|
|
#ifndef _PATH_BSHELL
|
|
# define _PATH_BSHELL "/bin/sh"
|
|
#endif
|
|
|
|
/*
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|
* We cannot use standard popen(3) here because we have to distinguish
|
|
* popen child process from other processes we trace, and standard popen(3)
|
|
* does not export its child's pid.
|
|
*/
|
|
static FILE *
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|
strace_popen(const char *command)
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|
{
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|
FILE *fp;
|
|
int fds[2];
|
|
|
|
swap_uid();
|
|
if (pipe(fds) < 0)
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|
perror_msg_and_die("pipe");
|
|
|
|
set_cloexec_flag(fds[1]); /* never fails */
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|
|
|
popen_pid = vfork();
|
|
if (popen_pid == -1)
|
|
perror_msg_and_die("vfork");
|
|
|
|
if (popen_pid == 0) {
|
|
/* child */
|
|
close(fds[1]);
|
|
if (fds[0] != 0) {
|
|
if (dup2(fds[0], 0))
|
|
perror_msg_and_die("dup2");
|
|
close(fds[0]);
|
|
}
|
|
execl(_PATH_BSHELL, "sh", "-c", command, NULL);
|
|
perror_msg_and_die("Can't execute '%s'", _PATH_BSHELL);
|
|
}
|
|
|
|
/* parent */
|
|
close(fds[0]);
|
|
swap_uid();
|
|
fp = fdopen(fds[1], "w");
|
|
if (!fp)
|
|
die_out_of_memory();
|
|
return fp;
|
|
}
|
|
|
|
void
|
|
tprintf(const char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
|
|
va_start(args, fmt);
|
|
if (current_tcp) {
|
|
int n = strace_vfprintf(current_tcp->outf, fmt, args);
|
|
if (n < 0) {
|
|
if (current_tcp->outf != stderr)
|
|
perror_msg("%s", outfname);
|
|
} else
|
|
current_tcp->curcol += n;
|
|
}
|
|
va_end(args);
|
|
}
|
|
|
|
void
|
|
tprints(const char *str)
|
|
{
|
|
if (current_tcp) {
|
|
int n = fputs_unlocked(str, current_tcp->outf);
|
|
if (n >= 0) {
|
|
current_tcp->curcol += strlen(str);
|
|
return;
|
|
}
|
|
if (current_tcp->outf != stderr)
|
|
perror_msg("%s", outfname);
|
|
}
|
|
}
|
|
|
|
void
|
|
line_ended(void)
|
|
{
|
|
if (current_tcp) {
|
|
current_tcp->curcol = 0;
|
|
fflush(current_tcp->outf);
|
|
}
|
|
if (printing_tcp) {
|
|
printing_tcp->curcol = 0;
|
|
printing_tcp = NULL;
|
|
}
|
|
}
|
|
|
|
void
|
|
printleader(struct tcb *tcp)
|
|
{
|
|
/* If -ff, "previous tcb we printed" is always the same as current,
|
|
* because we have per-tcb output files.
|
|
*/
|
|
if (followfork >= 2)
|
|
printing_tcp = tcp;
|
|
|
|
if (printing_tcp) {
|
|
current_tcp = printing_tcp;
|
|
if (printing_tcp->curcol != 0 && (followfork < 2 || printing_tcp == tcp)) {
|
|
/*
|
|
* case 1: we have a shared log (i.e. not -ff), and last line
|
|
* wasn't finished (same or different tcb, doesn't matter).
|
|
* case 2: split log, we are the same tcb, but our last line
|
|
* didn't finish ("SIGKILL nuked us after syscall entry" etc).
|
|
*/
|
|
tprints(" <unfinished ...>\n");
|
|
printing_tcp->curcol = 0;
|
|
}
|
|
}
|
|
|
|
printing_tcp = tcp;
|
|
current_tcp = tcp;
|
|
current_tcp->curcol = 0;
|
|
|
|
if (print_pid_pfx)
|
|
tprintf("%-5d ", tcp->pid);
|
|
else if (nprocs > 1 && !outfname)
|
|
tprintf("[pid %5u] ", tcp->pid);
|
|
|
|
if (tflag) {
|
|
char str[sizeof("HH:MM:SS")];
|
|
struct timeval tv, dtv;
|
|
static struct timeval otv;
|
|
|
|
gettimeofday(&tv, NULL);
|
|
if (rflag) {
|
|
if (otv.tv_sec == 0)
|
|
otv = tv;
|
|
tv_sub(&dtv, &tv, &otv);
|
|
tprintf("%6ld.%06ld ",
|
|
(long) dtv.tv_sec, (long) dtv.tv_usec);
|
|
otv = tv;
|
|
}
|
|
else if (tflag > 2) {
|
|
tprintf("%ld.%06ld ",
|
|
(long) tv.tv_sec, (long) tv.tv_usec);
|
|
}
|
|
else {
|
|
time_t local = tv.tv_sec;
|
|
strftime(str, sizeof(str), "%T", localtime(&local));
|
|
if (tflag > 1)
|
|
tprintf("%s.%06ld ", str, (long) tv.tv_usec);
|
|
else
|
|
tprintf("%s ", str);
|
|
}
|
|
}
|
|
if (iflag)
|
|
printcall(tcp);
|
|
}
|
|
|
|
void
|
|
tabto(void)
|
|
{
|
|
if (current_tcp->curcol < acolumn)
|
|
tprints(acolumn_spaces + current_tcp->curcol);
|
|
}
|
|
|
|
/* Should be only called directly *after successful attach* to a tracee.
|
|
* Otherwise, "strace -oFILE -ff -p<nonexistant_pid>"
|
|
* may create bogus empty FILE.<nonexistant_pid>, and then die.
|
|
*/
|
|
static void
|
|
newoutf(struct tcb *tcp)
|
|
{
|
|
tcp->outf = shared_log; /* if not -ff mode, the same file is for all */
|
|
if (followfork >= 2) {
|
|
char name[520 + sizeof(int) * 3];
|
|
sprintf(name, "%.512s.%u", outfname, tcp->pid);
|
|
tcp->outf = strace_fopen(name);
|
|
}
|
|
}
|
|
|
|
static void
|
|
expand_tcbtab(void)
|
|
{
|
|
/* Allocate some more TCBs and expand the table.
|
|
We don't want to relocate the TCBs because our
|
|
callers have pointers and it would be a pain.
|
|
So tcbtab is a table of pointers. Since we never
|
|
free the TCBs, we allocate a single chunk of many. */
|
|
int i = tcbtabsize;
|
|
struct tcb *newtcbs = calloc(tcbtabsize, sizeof(newtcbs[0]));
|
|
struct tcb **newtab = realloc(tcbtab, tcbtabsize * 2 * sizeof(tcbtab[0]));
|
|
if (!newtab || !newtcbs)
|
|
die_out_of_memory();
|
|
tcbtabsize *= 2;
|
|
tcbtab = newtab;
|
|
while (i < tcbtabsize)
|
|
tcbtab[i++] = newtcbs++;
|
|
}
|
|
|
|
static struct tcb *
|
|
alloctcb(int pid)
|
|
{
|
|
int i;
|
|
struct tcb *tcp;
|
|
|
|
if (nprocs == tcbtabsize)
|
|
expand_tcbtab();
|
|
|
|
for (i = 0; i < tcbtabsize; i++) {
|
|
tcp = tcbtab[i];
|
|
if ((tcp->flags & TCB_INUSE) == 0) {
|
|
memset(tcp, 0, sizeof(*tcp));
|
|
tcp->pid = pid;
|
|
tcp->flags = TCB_INUSE;
|
|
#if SUPPORTED_PERSONALITIES > 1
|
|
tcp->currpers = current_personality;
|
|
#endif
|
|
nprocs++;
|
|
if (debug_flag)
|
|
fprintf(stderr, "new tcb for pid %d, active tcbs:%d\n", tcp->pid, nprocs);
|
|
return tcp;
|
|
}
|
|
}
|
|
error_msg_and_die("bug in alloctcb");
|
|
}
|
|
|
|
static void
|
|
droptcb(struct tcb *tcp)
|
|
{
|
|
if (tcp->pid == 0)
|
|
return;
|
|
|
|
nprocs--;
|
|
if (debug_flag)
|
|
fprintf(stderr, "dropped tcb for pid %d, %d remain\n", tcp->pid, nprocs);
|
|
|
|
if (tcp->outf) {
|
|
if (followfork >= 2) {
|
|
if (tcp->curcol != 0)
|
|
fprintf(tcp->outf, " <detached ...>\n");
|
|
fclose(tcp->outf);
|
|
} else {
|
|
if (printing_tcp == tcp && tcp->curcol != 0)
|
|
fprintf(tcp->outf, " <detached ...>\n");
|
|
fflush(tcp->outf);
|
|
}
|
|
}
|
|
|
|
if (current_tcp == tcp)
|
|
current_tcp = NULL;
|
|
if (printing_tcp == tcp)
|
|
printing_tcp = NULL;
|
|
|
|
memset(tcp, 0, sizeof(*tcp));
|
|
}
|
|
|
|
/* Detach traced process.
|
|
* Never call DETACH twice on the same process as both unattached and
|
|
* attached-unstopped processes give the same ESRCH. For unattached process we
|
|
* would SIGSTOP it and wait for its SIGSTOP notification forever.
|
|
*/
|
|
static int
|
|
detach(struct tcb *tcp)
|
|
{
|
|
int error;
|
|
int status, sigstop_expected;
|
|
|
|
if (tcp->flags & TCB_BPTSET)
|
|
clearbpt(tcp);
|
|
|
|
/*
|
|
* Linux wrongly insists the child be stopped
|
|
* before detaching. Arghh. We go through hoops
|
|
* to make a clean break of things.
|
|
*/
|
|
#if defined(SPARC)
|
|
# undef PTRACE_DETACH
|
|
# define PTRACE_DETACH PTRACE_SUNDETACH
|
|
#endif
|
|
|
|
error = 0;
|
|
sigstop_expected = 0;
|
|
if (tcp->flags & TCB_ATTACHED) {
|
|
/*
|
|
* We attached but possibly didn't see the expected SIGSTOP.
|
|
* We must catch exactly one as otherwise the detached process
|
|
* would be left stopped (process state T).
|
|
*/
|
|
sigstop_expected = (tcp->flags & TCB_IGNORE_ONE_SIGSTOP);
|
|
error = ptrace(PTRACE_DETACH, tcp->pid, (char *) 1, 0);
|
|
if (error == 0) {
|
|
/* On a clear day, you can see forever. */
|
|
}
|
|
else if (errno != ESRCH) {
|
|
/* Shouldn't happen. */
|
|
perror_msg("detach: ptrace(PTRACE_DETACH, ...)");
|
|
}
|
|
else if (my_tkill(tcp->pid, 0) < 0) {
|
|
if (errno != ESRCH)
|
|
perror_msg("detach: checking sanity");
|
|
}
|
|
else if (!sigstop_expected && my_tkill(tcp->pid, SIGSTOP) < 0) {
|
|
if (errno != ESRCH)
|
|
perror_msg("detach: stopping child");
|
|
}
|
|
else
|
|
sigstop_expected = 1;
|
|
}
|
|
|
|
if (sigstop_expected) {
|
|
for (;;) {
|
|
#ifdef __WALL
|
|
if (waitpid(tcp->pid, &status, __WALL) < 0) {
|
|
if (errno == ECHILD) /* Already gone. */
|
|
break;
|
|
if (errno != EINVAL) {
|
|
perror_msg("detach: waiting");
|
|
break;
|
|
}
|
|
#endif /* __WALL */
|
|
/* No __WALL here. */
|
|
if (waitpid(tcp->pid, &status, 0) < 0) {
|
|
if (errno != ECHILD) {
|
|
perror_msg("detach: waiting");
|
|
break;
|
|
}
|
|
#ifdef __WCLONE
|
|
/* If no processes, try clones. */
|
|
if (waitpid(tcp->pid, &status, __WCLONE) < 0) {
|
|
if (errno != ECHILD)
|
|
perror_msg("detach: waiting");
|
|
break;
|
|
}
|
|
#endif /* __WCLONE */
|
|
}
|
|
#ifdef __WALL
|
|
}
|
|
#endif
|
|
if (!WIFSTOPPED(status)) {
|
|
/* Au revoir, mon ami. */
|
|
break;
|
|
}
|
|
if (WSTOPSIG(status) == SIGSTOP) {
|
|
ptrace_restart(PTRACE_DETACH, tcp, 0);
|
|
break;
|
|
}
|
|
error = ptrace_restart(PTRACE_CONT, tcp,
|
|
WSTOPSIG(status) == syscall_trap_sig ? 0
|
|
: WSTOPSIG(status));
|
|
if (error < 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!qflag && (tcp->flags & TCB_ATTACHED))
|
|
fprintf(stderr, "Process %u detached\n", tcp->pid);
|
|
|
|
droptcb(tcp);
|
|
|
|
return error;
|
|
}
|
|
|
|
static void
|
|
process_opt_p_list(char *opt)
|
|
{
|
|
while (*opt) {
|
|
/*
|
|
* We accept -p PID,PID; -p "`pidof PROG`"; -p "`pgrep PROG`".
|
|
* pidof uses space as delim, pgrep uses newline. :(
|
|
*/
|
|
int pid;
|
|
char *delim = opt + strcspn(opt, ", \n\t");
|
|
char c = *delim;
|
|
|
|
*delim = '\0';
|
|
pid = string_to_uint(opt);
|
|
if (pid <= 0) {
|
|
error_msg_and_die("Invalid process id: '%s'", opt);
|
|
}
|
|
if (pid == strace_tracer_pid) {
|
|
error_msg_and_die("I'm sorry, I can't let you do that, Dave.");
|
|
}
|
|
*delim = c;
|
|
alloctcb(pid);
|
|
if (c == '\0')
|
|
break;
|
|
opt = delim + 1;
|
|
}
|
|
}
|
|
|
|
static void
|
|
startup_attach(void)
|
|
{
|
|
int tcbi;
|
|
struct tcb *tcp;
|
|
|
|
/*
|
|
* Block user interruptions as we would leave the traced
|
|
* process stopped (process state T) if we would terminate in
|
|
* between PTRACE_ATTACH and wait4() on SIGSTOP.
|
|
* We rely on cleanup() from this point on.
|
|
*/
|
|
if (interactive)
|
|
sigprocmask(SIG_BLOCK, &blocked_set, NULL);
|
|
|
|
if (daemonized_tracer) {
|
|
pid_t pid = fork();
|
|
if (pid < 0) {
|
|
perror_msg_and_die("fork");
|
|
}
|
|
if (pid) { /* parent */
|
|
/*
|
|
* Wait for grandchild to attach to straced process
|
|
* (grandparent). Grandchild SIGKILLs us after it attached.
|
|
* Grandparent's wait() is unblocked by our death,
|
|
* it proceeds to exec the straced program.
|
|
*/
|
|
pause();
|
|
_exit(0); /* paranoia */
|
|
}
|
|
/* grandchild */
|
|
/* We will be the tracer process. Remember our new pid: */
|
|
strace_tracer_pid = getpid();
|
|
}
|
|
|
|
for (tcbi = 0; tcbi < tcbtabsize; tcbi++) {
|
|
tcp = tcbtab[tcbi];
|
|
|
|
if (!(tcp->flags & TCB_INUSE))
|
|
continue;
|
|
|
|
/* Is this a process we should attach to, but not yet attached? */
|
|
if (tcp->flags & TCB_ATTACHED)
|
|
continue; /* no, we already attached it */
|
|
|
|
if (followfork && !daemonized_tracer) {
|
|
char procdir[sizeof("/proc/%d/task") + sizeof(int) * 3];
|
|
DIR *dir;
|
|
|
|
sprintf(procdir, "/proc/%d/task", tcp->pid);
|
|
dir = opendir(procdir);
|
|
if (dir != NULL) {
|
|
unsigned int ntid = 0, nerr = 0;
|
|
struct_dirent *de;
|
|
|
|
while ((de = read_dir(dir)) != NULL) {
|
|
struct tcb *cur_tcp;
|
|
int tid;
|
|
|
|
if (de->d_fileno == 0)
|
|
continue;
|
|
/* we trust /proc filesystem */
|
|
tid = atoi(de->d_name);
|
|
if (tid <= 0)
|
|
continue;
|
|
++ntid;
|
|
if (ptrace_attach_or_seize(tid) < 0) {
|
|
++nerr;
|
|
if (debug_flag)
|
|
fprintf(stderr, "attach to pid %d failed\n", tid);
|
|
continue;
|
|
}
|
|
if (debug_flag)
|
|
fprintf(stderr, "attach to pid %d succeeded\n", tid);
|
|
cur_tcp = tcp;
|
|
if (tid != tcp->pid)
|
|
cur_tcp = alloctcb(tid);
|
|
cur_tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
|
|
newoutf(cur_tcp);
|
|
}
|
|
closedir(dir);
|
|
if (interactive) {
|
|
sigprocmask(SIG_SETMASK, &empty_set, NULL);
|
|
if (interrupted)
|
|
goto ret;
|
|
sigprocmask(SIG_BLOCK, &blocked_set, NULL);
|
|
}
|
|
ntid -= nerr;
|
|
if (ntid == 0) {
|
|
perror_msg("attach: ptrace(PTRACE_ATTACH, ...)");
|
|
droptcb(tcp);
|
|
continue;
|
|
}
|
|
if (!qflag) {
|
|
fprintf(stderr, ntid > 1
|
|
? "Process %u attached with %u threads\n"
|
|
: "Process %u attached\n",
|
|
tcp->pid, ntid);
|
|
}
|
|
if (!(tcp->flags & TCB_ATTACHED)) {
|
|
/* -p PID, we failed to attach to PID itself
|
|
* but did attach to some of its sibling threads.
|
|
* Drop PID's tcp.
|
|
*/
|
|
droptcb(tcp);
|
|
}
|
|
continue;
|
|
} /* if (opendir worked) */
|
|
} /* if (-f) */
|
|
if (ptrace_attach_or_seize(tcp->pid) < 0) {
|
|
perror_msg("attach: ptrace(PTRACE_ATTACH, ...)");
|
|
droptcb(tcp);
|
|
continue;
|
|
}
|
|
tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
|
|
newoutf(tcp);
|
|
if (debug_flag)
|
|
fprintf(stderr, "attach to pid %d (main) succeeded\n", tcp->pid);
|
|
|
|
if (daemonized_tracer) {
|
|
/*
|
|
* Make parent go away.
|
|
* Also makes grandparent's wait() unblock.
|
|
*/
|
|
kill(getppid(), SIGKILL);
|
|
}
|
|
|
|
if (!qflag)
|
|
fprintf(stderr,
|
|
"Process %u attached\n",
|
|
tcp->pid);
|
|
} /* for each tcbtab[] */
|
|
|
|
ret:
|
|
if (interactive)
|
|
sigprocmask(SIG_SETMASK, &empty_set, NULL);
|
|
}
|
|
|
|
/* Stack-o-phobic exec helper, in the hope to work around
|
|
* NOMMU + "daemonized tracer" difficulty.
|
|
*/
|
|
struct exec_params {
|
|
int fd_to_close;
|
|
uid_t run_euid;
|
|
gid_t run_egid;
|
|
char **argv;
|
|
char *pathname;
|
|
};
|
|
static struct exec_params params_for_tracee;
|
|
static void __attribute__ ((noinline, noreturn))
|
|
exec_or_die(void)
|
|
{
|
|
struct exec_params *params = ¶ms_for_tracee;
|
|
|
|
if (params->fd_to_close >= 0)
|
|
close(params->fd_to_close);
|
|
if (!daemonized_tracer && !use_seize) {
|
|
if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) < 0) {
|
|
perror_msg_and_die("ptrace(PTRACE_TRACEME, ...)");
|
|
}
|
|
}
|
|
|
|
if (username != NULL) {
|
|
/*
|
|
* It is important to set groups before we
|
|
* lose privileges on setuid.
|
|
*/
|
|
if (initgroups(username, run_gid) < 0) {
|
|
perror_msg_and_die("initgroups");
|
|
}
|
|
if (setregid(run_gid, params->run_egid) < 0) {
|
|
perror_msg_and_die("setregid");
|
|
}
|
|
if (setreuid(run_uid, params->run_euid) < 0) {
|
|
perror_msg_and_die("setreuid");
|
|
}
|
|
}
|
|
else if (geteuid() != 0)
|
|
if (setreuid(run_uid, run_uid) < 0) {
|
|
perror_msg_and_die("setreuid");
|
|
}
|
|
|
|
if (!daemonized_tracer) {
|
|
/*
|
|
* Induce a ptrace stop. Tracer (our parent)
|
|
* will resume us with PTRACE_SYSCALL and display
|
|
* the immediately following execve syscall.
|
|
* Can't do this on NOMMU systems, we are after
|
|
* vfork: parent is blocked, stopping would deadlock.
|
|
*/
|
|
if (!NOMMU_SYSTEM)
|
|
kill(getpid(), SIGSTOP);
|
|
} else {
|
|
alarm(3);
|
|
/* we depend on SIGCHLD set to SIG_DFL by init code */
|
|
/* if it happens to be SIG_IGN'ed, wait won't block */
|
|
wait(NULL);
|
|
alarm(0);
|
|
}
|
|
|
|
execv(params->pathname, params->argv);
|
|
perror_msg_and_die("exec");
|
|
}
|
|
|
|
static void
|
|
startup_child(char **argv)
|
|
{
|
|
struct_stat statbuf;
|
|
const char *filename;
|
|
char pathname[MAXPATHLEN];
|
|
int pid;
|
|
struct tcb *tcp;
|
|
|
|
filename = argv[0];
|
|
if (strchr(filename, '/')) {
|
|
if (strlen(filename) > sizeof pathname - 1) {
|
|
errno = ENAMETOOLONG;
|
|
perror_msg_and_die("exec");
|
|
}
|
|
strcpy(pathname, filename);
|
|
}
|
|
#ifdef USE_DEBUGGING_EXEC
|
|
/*
|
|
* Debuggers customarily check the current directory
|
|
* first regardless of the path but doing that gives
|
|
* security geeks a panic attack.
|
|
*/
|
|
else if (stat_file(filename, &statbuf) == 0)
|
|
strcpy(pathname, filename);
|
|
#endif /* USE_DEBUGGING_EXEC */
|
|
else {
|
|
const char *path;
|
|
int m, n, len;
|
|
|
|
for (path = getenv("PATH"); path && *path; path += m) {
|
|
const char *colon = strchr(path, ':');
|
|
if (colon) {
|
|
n = colon - path;
|
|
m = n + 1;
|
|
}
|
|
else
|
|
m = n = strlen(path);
|
|
if (n == 0) {
|
|
if (!getcwd(pathname, MAXPATHLEN))
|
|
continue;
|
|
len = strlen(pathname);
|
|
}
|
|
else if (n > sizeof pathname - 1)
|
|
continue;
|
|
else {
|
|
strncpy(pathname, path, n);
|
|
len = n;
|
|
}
|
|
if (len && pathname[len - 1] != '/')
|
|
pathname[len++] = '/';
|
|
strcpy(pathname + len, filename);
|
|
if (stat_file(pathname, &statbuf) == 0 &&
|
|
/* Accept only regular files
|
|
with some execute bits set.
|
|
XXX not perfect, might still fail */
|
|
S_ISREG(statbuf.st_mode) &&
|
|
(statbuf.st_mode & 0111))
|
|
break;
|
|
}
|
|
}
|
|
if (stat_file(pathname, &statbuf) < 0) {
|
|
perror_msg_and_die("Can't stat '%s'", filename);
|
|
}
|
|
|
|
params_for_tracee.fd_to_close = (shared_log != stderr) ? fileno(shared_log) : -1;
|
|
params_for_tracee.run_euid = (statbuf.st_mode & S_ISUID) ? statbuf.st_uid : run_uid;
|
|
params_for_tracee.run_egid = (statbuf.st_mode & S_ISGID) ? statbuf.st_gid : run_gid;
|
|
params_for_tracee.argv = argv;
|
|
/*
|
|
* On NOMMU, can be safely freed only after execve in tracee.
|
|
* It's hard to know when that happens, so we just leak it.
|
|
*/
|
|
params_for_tracee.pathname = NOMMU_SYSTEM ? strdup(pathname) : pathname;
|
|
|
|
#if defined HAVE_PRCTL && defined PR_SET_PTRACER && defined PR_SET_PTRACER_ANY
|
|
if (daemonized_tracer)
|
|
prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY);
|
|
#endif
|
|
|
|
strace_child = pid = fork();
|
|
if (pid < 0) {
|
|
perror_msg_and_die("fork");
|
|
}
|
|
if ((pid != 0 && daemonized_tracer)
|
|
|| (pid == 0 && !daemonized_tracer)
|
|
) {
|
|
/* We are to become the tracee. Two cases:
|
|
* -D: we are parent
|
|
* not -D: we are child
|
|
*/
|
|
exec_or_die();
|
|
}
|
|
|
|
/* We are the tracer */
|
|
|
|
if (!daemonized_tracer) {
|
|
if (!use_seize) {
|
|
/* child did PTRACE_TRACEME, nothing to do in parent */
|
|
} else {
|
|
if (!NOMMU_SYSTEM) {
|
|
/* Wait until child stopped itself */
|
|
int status;
|
|
while (waitpid(pid, &status, WSTOPPED) < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
perror_msg_and_die("waitpid");
|
|
}
|
|
if (!WIFSTOPPED(status) || WSTOPSIG(status) != SIGSTOP) {
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("Unexpected wait status %x", status);
|
|
}
|
|
}
|
|
/* Else: NOMMU case, we have no way to sync.
|
|
* Just attach to it as soon as possible.
|
|
* This means that we may miss a few first syscalls...
|
|
*/
|
|
|
|
if (ptrace_attach_or_seize(pid)) {
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("Can't attach to %d", pid);
|
|
}
|
|
if (!NOMMU_SYSTEM)
|
|
kill(pid, SIGCONT);
|
|
}
|
|
tcp = alloctcb(pid);
|
|
if (!NOMMU_SYSTEM)
|
|
tcp->flags |= TCB_ATTACHED | TCB_STRACE_CHILD | TCB_STARTUP | post_attach_sigstop;
|
|
else
|
|
tcp->flags |= TCB_ATTACHED | TCB_STRACE_CHILD | TCB_STARTUP;
|
|
newoutf(tcp);
|
|
}
|
|
else {
|
|
/* With -D, we are *child* here, IOW: different pid. Fetch it: */
|
|
strace_tracer_pid = getpid();
|
|
/* The tracee is our parent: */
|
|
pid = getppid();
|
|
alloctcb(pid);
|
|
/* attaching will be done later, by startup_attach */
|
|
/* note: we don't do newoutf(tcp) here either! */
|
|
|
|
/* NOMMU BUG! -D mode is active, we (child) return,
|
|
* and we will scribble over parent's stack!
|
|
* When parent later unpauses, it segfaults.
|
|
*
|
|
* We work around it
|
|
* (1) by declaring exec_or_die() NORETURN,
|
|
* hopefully compiler will just jump to it
|
|
* instead of call (won't push anything to stack),
|
|
* (2) by trying very hard in exec_or_die()
|
|
* to not use any stack,
|
|
* (3) having a really big (MAXPATHLEN) stack object
|
|
* in this function, which creates a "buffer" between
|
|
* child's and parent's stack pointers.
|
|
* This may save us if (1) and (2) failed
|
|
* and compiler decided to use stack in exec_or_die() anyway
|
|
* (happens on i386 because of stack parameter passing).
|
|
*
|
|
* A cleaner solution is to use makecontext + setcontext
|
|
* to create a genuine separate stack and execute on it.
|
|
*/
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Test whether the kernel support PTRACE_O_TRACECLONE et al options.
|
|
* First fork a new child, call ptrace with PTRACE_SETOPTIONS on it,
|
|
* and then see which options are supported by the kernel.
|
|
*/
|
|
static int
|
|
test_ptrace_setoptions_followfork(void)
|
|
{
|
|
int pid, expected_grandchild = 0, found_grandchild = 0;
|
|
const unsigned int test_options = PTRACE_O_TRACECLONE |
|
|
PTRACE_O_TRACEFORK |
|
|
PTRACE_O_TRACEVFORK;
|
|
|
|
/* Need fork for test. NOMMU has no forks */
|
|
if (NOMMU_SYSTEM)
|
|
goto worked; /* be bold, and pretend that test succeeded */
|
|
|
|
pid = fork();
|
|
if (pid < 0)
|
|
perror_msg_and_die("fork");
|
|
if (pid == 0) {
|
|
pid = getpid();
|
|
if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) < 0)
|
|
perror_msg_and_die("%s: PTRACE_TRACEME doesn't work",
|
|
__func__);
|
|
kill_save_errno(pid, SIGSTOP);
|
|
if (fork() < 0)
|
|
perror_msg_and_die("fork");
|
|
_exit(0);
|
|
}
|
|
|
|
while (1) {
|
|
int status, tracee_pid;
|
|
|
|
errno = 0;
|
|
tracee_pid = wait(&status);
|
|
if (tracee_pid <= 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
if (errno == ECHILD)
|
|
break;
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("%s: unexpected wait result %d",
|
|
__func__, tracee_pid);
|
|
}
|
|
if (WIFEXITED(status)) {
|
|
if (WEXITSTATUS(status)) {
|
|
if (tracee_pid != pid)
|
|
kill_save_errno(pid, SIGKILL);
|
|
error_msg_and_die("%s: unexpected exit status %u",
|
|
__func__, WEXITSTATUS(status));
|
|
}
|
|
continue;
|
|
}
|
|
if (WIFSIGNALED(status)) {
|
|
if (tracee_pid != pid)
|
|
kill_save_errno(pid, SIGKILL);
|
|
error_msg_and_die("%s: unexpected signal %u",
|
|
__func__, WTERMSIG(status));
|
|
}
|
|
if (!WIFSTOPPED(status)) {
|
|
if (tracee_pid != pid)
|
|
kill_save_errno(tracee_pid, SIGKILL);
|
|
kill_save_errno(pid, SIGKILL);
|
|
error_msg_and_die("%s: unexpected wait status %x",
|
|
__func__, status);
|
|
}
|
|
if (tracee_pid != pid) {
|
|
found_grandchild = tracee_pid;
|
|
if (ptrace(PTRACE_CONT, tracee_pid, 0, 0) < 0) {
|
|
kill_save_errno(tracee_pid, SIGKILL);
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("PTRACE_CONT doesn't work");
|
|
}
|
|
continue;
|
|
}
|
|
switch (WSTOPSIG(status)) {
|
|
case SIGSTOP:
|
|
if (ptrace(PTRACE_SETOPTIONS, pid, 0, test_options) < 0
|
|
&& errno != EINVAL && errno != EIO)
|
|
perror_msg("PTRACE_SETOPTIONS");
|
|
break;
|
|
case SIGTRAP:
|
|
if (status >> 16 == PTRACE_EVENT_FORK) {
|
|
long msg = 0;
|
|
|
|
if (ptrace(PTRACE_GETEVENTMSG, pid,
|
|
NULL, (long) &msg) == 0)
|
|
expected_grandchild = msg;
|
|
}
|
|
break;
|
|
}
|
|
if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0) {
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("PTRACE_SYSCALL doesn't work");
|
|
}
|
|
}
|
|
if (expected_grandchild && expected_grandchild == found_grandchild) {
|
|
worked:
|
|
ptrace_setoptions |= test_options;
|
|
if (debug_flag)
|
|
fprintf(stderr, "ptrace_setoptions = %#x\n",
|
|
ptrace_setoptions);
|
|
return 0;
|
|
}
|
|
error_msg("Test for PTRACE_O_TRACECLONE failed, "
|
|
"giving up using this feature.");
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Test whether the kernel support PTRACE_O_TRACESYSGOOD.
|
|
* First fork a new child, call ptrace(PTRACE_SETOPTIONS) on it,
|
|
* and then see whether it will stop with (SIGTRAP | 0x80).
|
|
*
|
|
* Use of this option enables correct handling of user-generated SIGTRAPs,
|
|
* and SIGTRAPs generated by special instructions such as int3 on x86:
|
|
* _start: .globl _start
|
|
* int3
|
|
* movl $42, %ebx
|
|
* movl $1, %eax
|
|
* int $0x80
|
|
* (compile with: "gcc -nostartfiles -nostdlib -o int3 int3.S")
|
|
*/
|
|
static int
|
|
test_ptrace_setoptions_for_all(void)
|
|
{
|
|
const unsigned int test_options = PTRACE_O_TRACESYSGOOD |
|
|
PTRACE_O_TRACEEXEC;
|
|
int pid;
|
|
int it_worked = 0;
|
|
|
|
/* Need fork for test. NOMMU has no forks */
|
|
if (NOMMU_SYSTEM)
|
|
goto worked; /* be bold, and pretend that test succeeded */
|
|
|
|
pid = fork();
|
|
if (pid < 0)
|
|
perror_msg_and_die("fork");
|
|
|
|
if (pid == 0) {
|
|
pid = getpid();
|
|
if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) < 0)
|
|
/* Note: exits with exitcode 1 */
|
|
perror_msg_and_die("%s: PTRACE_TRACEME doesn't work",
|
|
__func__);
|
|
kill(pid, SIGSTOP);
|
|
_exit(0); /* parent should see entry into this syscall */
|
|
}
|
|
|
|
while (1) {
|
|
int status, tracee_pid;
|
|
|
|
errno = 0;
|
|
tracee_pid = wait(&status);
|
|
if (tracee_pid <= 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("%s: unexpected wait result %d",
|
|
__func__, tracee_pid);
|
|
}
|
|
if (WIFEXITED(status)) {
|
|
if (WEXITSTATUS(status) == 0)
|
|
break;
|
|
error_msg_and_die("%s: unexpected exit status %u",
|
|
__func__, WEXITSTATUS(status));
|
|
}
|
|
if (WIFSIGNALED(status)) {
|
|
error_msg_and_die("%s: unexpected signal %u",
|
|
__func__, WTERMSIG(status));
|
|
}
|
|
if (!WIFSTOPPED(status)) {
|
|
kill(pid, SIGKILL);
|
|
error_msg_and_die("%s: unexpected wait status %x",
|
|
__func__, status);
|
|
}
|
|
if (WSTOPSIG(status) == SIGSTOP) {
|
|
/*
|
|
* We don't check "options aren't accepted" error.
|
|
* If it happens, we'll never get (SIGTRAP | 0x80),
|
|
* and thus will decide to not use the option.
|
|
* IOW: the outcome of the test will be correct.
|
|
*/
|
|
if (ptrace(PTRACE_SETOPTIONS, pid, 0L, test_options) < 0
|
|
&& errno != EINVAL && errno != EIO)
|
|
perror_msg("PTRACE_SETOPTIONS");
|
|
}
|
|
if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
|
|
it_worked = 1;
|
|
}
|
|
if (ptrace(PTRACE_SYSCALL, pid, 0L, 0L) < 0) {
|
|
kill_save_errno(pid, SIGKILL);
|
|
perror_msg_and_die("PTRACE_SYSCALL doesn't work");
|
|
}
|
|
}
|
|
|
|
if (it_worked) {
|
|
worked:
|
|
syscall_trap_sig = (SIGTRAP | 0x80);
|
|
ptrace_setoptions |= test_options;
|
|
if (debug_flag)
|
|
fprintf(stderr, "ptrace_setoptions = %#x\n",
|
|
ptrace_setoptions);
|
|
return 0;
|
|
}
|
|
|
|
error_msg("Test for PTRACE_O_TRACESYSGOOD failed, "
|
|
"giving up using this feature.");
|
|
return 1;
|
|
}
|
|
|
|
#if USE_SEIZE
|
|
static void
|
|
test_ptrace_seize(void)
|
|
{
|
|
int pid;
|
|
|
|
/* Need fork for test. NOMMU has no forks */
|
|
if (NOMMU_SYSTEM) {
|
|
post_attach_sigstop = 0; /* this sets use_seize to 1 */
|
|
return;
|
|
}
|
|
|
|
pid = fork();
|
|
if (pid < 0)
|
|
perror_msg_and_die("fork");
|
|
|
|
if (pid == 0) {
|
|
pause();
|
|
_exit(0);
|
|
}
|
|
|
|
/* PTRACE_SEIZE, unlike ATTACH, doesn't force tracee to trap. After
|
|
* attaching tracee continues to run unless a trap condition occurs.
|
|
* PTRACE_SEIZE doesn't affect signal or group stop state.
|
|
*/
|
|
if (ptrace(PTRACE_SEIZE, pid, 0, 0) == 0) {
|
|
post_attach_sigstop = 0; /* this sets use_seize to 1 */
|
|
} else if (debug_flag) {
|
|
fprintf(stderr, "PTRACE_SEIZE doesn't work\n");
|
|
}
|
|
|
|
kill(pid, SIGKILL);
|
|
|
|
while (1) {
|
|
int status, tracee_pid;
|
|
|
|
errno = 0;
|
|
tracee_pid = waitpid(pid, &status, 0);
|
|
if (tracee_pid <= 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
perror_msg_and_die("%s: unexpected wait result %d",
|
|
__func__, tracee_pid);
|
|
}
|
|
if (WIFSIGNALED(status)) {
|
|
return;
|
|
}
|
|
error_msg_and_die("%s: unexpected wait status %x",
|
|
__func__, status);
|
|
}
|
|
}
|
|
#else /* !USE_SEIZE */
|
|
# define test_ptrace_seize() ((void)0)
|
|
#endif
|
|
|
|
static unsigned
|
|
get_os_release(void)
|
|
{
|
|
unsigned rel;
|
|
const char *p;
|
|
struct utsname u;
|
|
if (uname(&u) < 0)
|
|
perror_msg_and_die("uname");
|
|
/* u.release has this form: "3.2.9[-some-garbage]" */
|
|
rel = 0;
|
|
p = u.release;
|
|
for (;;) {
|
|
if (!(*p >= '0' && *p <= '9'))
|
|
error_msg_and_die("Bad OS release string: '%s'", u.release);
|
|
/* Note: this open-codes KERNEL_VERSION(): */
|
|
rel = (rel << 8) | atoi(p);
|
|
if (rel >= KERNEL_VERSION(1,0,0))
|
|
break;
|
|
while (*p >= '0' && *p <= '9')
|
|
p++;
|
|
if (*p != '.') {
|
|
if (rel >= KERNEL_VERSION(0,1,0)) {
|
|
/* "X.Y-something" means "X.Y.0" */
|
|
rel <<= 8;
|
|
break;
|
|
}
|
|
error_msg_and_die("Bad OS release string: '%s'", u.release);
|
|
}
|
|
p++;
|
|
}
|
|
return rel;
|
|
}
|
|
|
|
/*
|
|
* Initialization part of main() was eating much stack (~0.5k),
|
|
* which was unused after init.
|
|
* We can reuse it if we move init code into a separate function.
|
|
*
|
|
* Don't want main() to inline us and defeat the reason
|
|
* we have a separate function.
|
|
*/
|
|
static void __attribute__ ((noinline))
|
|
init(int argc, char *argv[])
|
|
{
|
|
struct tcb *tcp;
|
|
int c, i;
|
|
int optF = 0;
|
|
struct sigaction sa;
|
|
|
|
progname = argv[0] ? argv[0] : "strace";
|
|
|
|
/* Make sure SIGCHLD has the default action so that waitpid
|
|
definitely works without losing track of children. The user
|
|
should not have given us a bogus state to inherit, but he might
|
|
have. Arguably we should detect SIG_IGN here and pass it on
|
|
to children, but probably noone really needs that. */
|
|
signal(SIGCHLD, SIG_DFL);
|
|
|
|
strace_tracer_pid = getpid();
|
|
|
|
os_release = get_os_release();
|
|
|
|
/* Allocate the initial tcbtab. */
|
|
tcbtabsize = argc; /* Surely enough for all -p args. */
|
|
tcbtab = calloc(tcbtabsize, sizeof(tcbtab[0]));
|
|
if (!tcbtab)
|
|
die_out_of_memory();
|
|
tcp = calloc(tcbtabsize, sizeof(*tcp));
|
|
if (!tcp)
|
|
die_out_of_memory();
|
|
for (c = 0; c < tcbtabsize; c++)
|
|
tcbtab[c] = tcp++;
|
|
|
|
shared_log = stderr;
|
|
set_sortby(DEFAULT_SORTBY);
|
|
set_personality(DEFAULT_PERSONALITY);
|
|
qualify("trace=all");
|
|
qualify("abbrev=all");
|
|
qualify("verbose=all");
|
|
#if DEFAULT_QUAL_FLAGS != (QUAL_TRACE | QUAL_ABBREV | QUAL_VERBOSE)
|
|
# error Bug in DEFAULT_QUAL_FLAGS
|
|
#endif
|
|
qualify("signal=all");
|
|
while ((c = getopt(argc, argv,
|
|
"+b:cCdfFhiqrtTvVxyz"
|
|
"D"
|
|
"a:e:o:O:p:s:S:u:E:P:I:")) != EOF) {
|
|
switch (c) {
|
|
case 'b':
|
|
if (strcmp(optarg, "execve") != 0)
|
|
error_msg_and_die("Syscall '%s' for -b isn't supported",
|
|
optarg);
|
|
detach_on_execve = 1;
|
|
break;
|
|
case 'c':
|
|
if (cflag == CFLAG_BOTH) {
|
|
error_msg_and_die("-c and -C are mutually exclusive");
|
|
}
|
|
cflag = CFLAG_ONLY_STATS;
|
|
break;
|
|
case 'C':
|
|
if (cflag == CFLAG_ONLY_STATS) {
|
|
error_msg_and_die("-c and -C are mutually exclusive");
|
|
}
|
|
cflag = CFLAG_BOTH;
|
|
break;
|
|
case 'd':
|
|
debug_flag = 1;
|
|
break;
|
|
case 'D':
|
|
daemonized_tracer = 1;
|
|
break;
|
|
case 'F':
|
|
optF = 1;
|
|
break;
|
|
case 'f':
|
|
followfork++;
|
|
break;
|
|
case 'h':
|
|
usage(stdout, 0);
|
|
break;
|
|
case 'i':
|
|
iflag = 1;
|
|
break;
|
|
case 'q':
|
|
qflag++;
|
|
break;
|
|
case 'r':
|
|
rflag = 1;
|
|
/* fall through to tflag++ */
|
|
case 't':
|
|
tflag++;
|
|
break;
|
|
case 'T':
|
|
Tflag = 1;
|
|
break;
|
|
case 'x':
|
|
xflag++;
|
|
break;
|
|
case 'y':
|
|
show_fd_path = 1;
|
|
break;
|
|
case 'v':
|
|
qualify("abbrev=none");
|
|
break;
|
|
case 'V':
|
|
printf("%s -- version %s\n", PACKAGE_NAME, VERSION);
|
|
exit(0);
|
|
break;
|
|
case 'z':
|
|
not_failing_only = 1;
|
|
break;
|
|
case 'a':
|
|
acolumn = string_to_uint(optarg);
|
|
if (acolumn < 0)
|
|
error_opt_arg(c, optarg);
|
|
break;
|
|
case 'e':
|
|
qualify(optarg);
|
|
break;
|
|
case 'o':
|
|
outfname = strdup(optarg);
|
|
break;
|
|
case 'O':
|
|
i = string_to_uint(optarg);
|
|
if (i < 0)
|
|
error_opt_arg(c, optarg);
|
|
set_overhead(i);
|
|
break;
|
|
case 'p':
|
|
process_opt_p_list(optarg);
|
|
break;
|
|
case 'P':
|
|
pathtrace_select(optarg);
|
|
break;
|
|
case 's':
|
|
i = string_to_uint(optarg);
|
|
if (i < 0)
|
|
error_opt_arg(c, optarg);
|
|
max_strlen = i;
|
|
break;
|
|
case 'S':
|
|
set_sortby(optarg);
|
|
break;
|
|
case 'u':
|
|
username = strdup(optarg);
|
|
break;
|
|
case 'E':
|
|
if (putenv(optarg) < 0)
|
|
die_out_of_memory();
|
|
break;
|
|
case 'I':
|
|
opt_intr = string_to_uint(optarg);
|
|
if (opt_intr <= 0 || opt_intr >= NUM_INTR_OPTS)
|
|
error_opt_arg(c, optarg);
|
|
break;
|
|
default:
|
|
usage(stderr, 1);
|
|
break;
|
|
}
|
|
}
|
|
argv += optind;
|
|
/* argc -= optind; - no need, argc is not used below */
|
|
|
|
acolumn_spaces = malloc(acolumn + 1);
|
|
if (!acolumn_spaces)
|
|
die_out_of_memory();
|
|
memset(acolumn_spaces, ' ', acolumn);
|
|
acolumn_spaces[acolumn] = '\0';
|
|
|
|
/* Must have PROG [ARGS], or -p PID. Not both. */
|
|
if (!argv[0] == !nprocs)
|
|
usage(stderr, 1);
|
|
|
|
if (nprocs != 0 && daemonized_tracer) {
|
|
error_msg_and_die("-D and -p are mutually exclusive");
|
|
}
|
|
|
|
if (!followfork)
|
|
followfork = optF;
|
|
|
|
if (followfork >= 2 && cflag) {
|
|
error_msg_and_die("(-c or -C) and -ff are mutually exclusive");
|
|
}
|
|
|
|
/* See if they want to run as another user. */
|
|
if (username != NULL) {
|
|
struct passwd *pent;
|
|
|
|
if (getuid() != 0 || geteuid() != 0) {
|
|
error_msg_and_die("You must be root to use the -u option");
|
|
}
|
|
pent = getpwnam(username);
|
|
if (pent == NULL) {
|
|
error_msg_and_die("Cannot find user '%s'", username);
|
|
}
|
|
run_uid = pent->pw_uid;
|
|
run_gid = pent->pw_gid;
|
|
}
|
|
else {
|
|
run_uid = getuid();
|
|
run_gid = getgid();
|
|
}
|
|
|
|
/*
|
|
* On any reasonably recent Linux kernel (circa about 2.5.46)
|
|
* need_fork_exec_workarounds should stay 0 after these tests:
|
|
*/
|
|
/*need_fork_exec_workarounds = 0; - already is */
|
|
if (followfork)
|
|
need_fork_exec_workarounds = test_ptrace_setoptions_followfork();
|
|
need_fork_exec_workarounds |= test_ptrace_setoptions_for_all();
|
|
test_ptrace_seize();
|
|
|
|
/* Check if they want to redirect the output. */
|
|
if (outfname) {
|
|
/* See if they want to pipe the output. */
|
|
if (outfname[0] == '|' || outfname[0] == '!') {
|
|
/*
|
|
* We can't do the <outfname>.PID funny business
|
|
* when using popen, so prohibit it.
|
|
*/
|
|
if (followfork >= 2)
|
|
error_msg_and_die("Piping the output and -ff are mutually exclusive");
|
|
shared_log = strace_popen(outfname + 1);
|
|
}
|
|
else if (followfork < 2)
|
|
shared_log = strace_fopen(outfname);
|
|
} else {
|
|
/* -ff without -o FILE is the same as single -f */
|
|
if (followfork >= 2)
|
|
followfork = 1;
|
|
}
|
|
|
|
if (!outfname || outfname[0] == '|' || outfname[0] == '!') {
|
|
char *buf = malloc(BUFSIZ);
|
|
if (!buf)
|
|
die_out_of_memory();
|
|
setvbuf(shared_log, buf, _IOLBF, BUFSIZ);
|
|
}
|
|
if (outfname && argv[0]) {
|
|
if (!opt_intr)
|
|
opt_intr = INTR_NEVER;
|
|
qflag = 1;
|
|
}
|
|
if (!opt_intr)
|
|
opt_intr = INTR_WHILE_WAIT;
|
|
|
|
/* argv[0] -pPID -oFILE Default interactive setting
|
|
* yes 0 0 INTR_WHILE_WAIT
|
|
* no 1 0 INTR_WHILE_WAIT
|
|
* yes 0 1 INTR_NEVER
|
|
* no 1 1 INTR_WHILE_WAIT
|
|
*/
|
|
|
|
sigemptyset(&empty_set);
|
|
sigemptyset(&blocked_set);
|
|
|
|
/* startup_child() must be called before the signal handlers get
|
|
* installed below as they are inherited into the spawned process.
|
|
* Also we do not need to be protected by them as during interruption
|
|
* in the startup_child() mode we kill the spawned process anyway.
|
|
*/
|
|
if (argv[0]) {
|
|
if (!NOMMU_SYSTEM || daemonized_tracer)
|
|
hide_log_until_execve = 1;
|
|
skip_one_b_execve = 1;
|
|
startup_child(argv);
|
|
}
|
|
|
|
sa.sa_handler = SIG_IGN;
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags = 0;
|
|
sigaction(SIGTTOU, &sa, NULL); /* SIG_IGN */
|
|
sigaction(SIGTTIN, &sa, NULL); /* SIG_IGN */
|
|
if (opt_intr != INTR_ANYWHERE) {
|
|
if (opt_intr == INTR_BLOCK_TSTP_TOO)
|
|
sigaction(SIGTSTP, &sa, NULL); /* SIG_IGN */
|
|
/*
|
|
* In interactive mode (if no -o OUTFILE, or -p PID is used),
|
|
* fatal signals are blocked while syscall stop is processed,
|
|
* and acted on in between, when waiting for new syscall stops.
|
|
* In non-interactive mode, signals are ignored.
|
|
*/
|
|
if (opt_intr == INTR_WHILE_WAIT) {
|
|
sigaddset(&blocked_set, SIGHUP);
|
|
sigaddset(&blocked_set, SIGINT);
|
|
sigaddset(&blocked_set, SIGQUIT);
|
|
sigaddset(&blocked_set, SIGPIPE);
|
|
sigaddset(&blocked_set, SIGTERM);
|
|
sa.sa_handler = interrupt;
|
|
}
|
|
/* SIG_IGN, or set handler for these */
|
|
sigaction(SIGHUP, &sa, NULL);
|
|
sigaction(SIGINT, &sa, NULL);
|
|
sigaction(SIGQUIT, &sa, NULL);
|
|
sigaction(SIGPIPE, &sa, NULL);
|
|
sigaction(SIGTERM, &sa, NULL);
|
|
}
|
|
if (nprocs != 0 || daemonized_tracer)
|
|
startup_attach();
|
|
|
|
/* Do we want pids printed in our -o OUTFILE?
|
|
* -ff: no (every pid has its own file); or
|
|
* -f: yes (there can be more pids in the future); or
|
|
* -p PID1,PID2: yes (there are already more than one pid)
|
|
*/
|
|
print_pid_pfx = (outfname && followfork < 2 && (followfork == 1 || nprocs > 1));
|
|
}
|
|
|
|
static struct tcb *
|
|
pid2tcb(int pid)
|
|
{
|
|
int i;
|
|
|
|
if (pid <= 0)
|
|
return NULL;
|
|
|
|
for (i = 0; i < tcbtabsize; i++) {
|
|
struct tcb *tcp = tcbtab[i];
|
|
if (tcp->pid == pid && (tcp->flags & TCB_INUSE))
|
|
return tcp;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
cleanup(void)
|
|
{
|
|
int i;
|
|
struct tcb *tcp;
|
|
int fatal_sig;
|
|
|
|
/* 'interrupted' is a volatile object, fetch it only once */
|
|
fatal_sig = interrupted;
|
|
if (!fatal_sig)
|
|
fatal_sig = SIGTERM;
|
|
|
|
for (i = 0; i < tcbtabsize; i++) {
|
|
tcp = tcbtab[i];
|
|
if (!(tcp->flags & TCB_INUSE))
|
|
continue;
|
|
if (debug_flag)
|
|
fprintf(stderr,
|
|
"cleanup: looking at pid %u\n", tcp->pid);
|
|
if (tcp->flags & TCB_STRACE_CHILD) {
|
|
kill(tcp->pid, SIGCONT);
|
|
kill(tcp->pid, fatal_sig);
|
|
}
|
|
detach(tcp);
|
|
}
|
|
if (cflag)
|
|
call_summary(shared_log);
|
|
}
|
|
|
|
static void
|
|
interrupt(int sig)
|
|
{
|
|
interrupted = sig;
|
|
}
|
|
|
|
static int
|
|
trace(void)
|
|
{
|
|
struct rusage ru;
|
|
struct rusage *rup = cflag ? &ru : NULL;
|
|
#ifdef __WALL
|
|
static int wait4_options = __WALL;
|
|
#endif
|
|
|
|
while (nprocs != 0) {
|
|
int pid;
|
|
int wait_errno;
|
|
int status, sig;
|
|
int stopped;
|
|
struct tcb *tcp;
|
|
unsigned event;
|
|
|
|
if (interrupted)
|
|
return 0;
|
|
if (interactive)
|
|
sigprocmask(SIG_SETMASK, &empty_set, NULL);
|
|
#ifdef __WALL
|
|
pid = wait4(-1, &status, wait4_options, rup);
|
|
if (pid < 0 && (wait4_options & __WALL) && errno == EINVAL) {
|
|
/* this kernel does not support __WALL */
|
|
wait4_options &= ~__WALL;
|
|
pid = wait4(-1, &status, wait4_options, rup);
|
|
}
|
|
if (pid < 0 && !(wait4_options & __WALL) && errno == ECHILD) {
|
|
/* most likely a "cloned" process */
|
|
pid = wait4(-1, &status, __WCLONE, rup);
|
|
if (pid < 0) {
|
|
perror_msg("wait4(__WCLONE) failed");
|
|
}
|
|
}
|
|
#else
|
|
pid = wait4(-1, &status, 0, rup);
|
|
#endif /* __WALL */
|
|
wait_errno = errno;
|
|
if (interactive)
|
|
sigprocmask(SIG_BLOCK, &blocked_set, NULL);
|
|
|
|
if (pid < 0) {
|
|
switch (wait_errno) {
|
|
case EINTR:
|
|
continue;
|
|
case ECHILD:
|
|
/*
|
|
* We would like to verify this case
|
|
* but sometimes a race in Solbourne's
|
|
* version of SunOS sometimes reports
|
|
* ECHILD before sending us SIGCHILD.
|
|
*/
|
|
return 0;
|
|
default:
|
|
errno = wait_errno;
|
|
perror_msg("wait");
|
|
return -1;
|
|
}
|
|
}
|
|
if (pid == popen_pid) {
|
|
if (WIFEXITED(status) || WIFSIGNALED(status))
|
|
popen_pid = 0;
|
|
continue;
|
|
}
|
|
|
|
event = ((unsigned)status >> 16);
|
|
if (debug_flag) {
|
|
char buf[sizeof("WIFEXITED,exitcode=%u") + sizeof(int)*3 /*paranoia:*/ + 16];
|
|
char evbuf[sizeof(",PTRACE_EVENT_?? (%u)") + sizeof(int)*3 /*paranoia:*/ + 16];
|
|
strcpy(buf, "???");
|
|
if (WIFSIGNALED(status))
|
|
#ifdef WCOREDUMP
|
|
sprintf(buf, "WIFSIGNALED,%ssig=%s",
|
|
WCOREDUMP(status) ? "core," : "",
|
|
signame(WTERMSIG(status)));
|
|
#else
|
|
sprintf(buf, "WIFSIGNALED,sig=%s",
|
|
signame(WTERMSIG(status)));
|
|
#endif
|
|
if (WIFEXITED(status))
|
|
sprintf(buf, "WIFEXITED,exitcode=%u", WEXITSTATUS(status));
|
|
if (WIFSTOPPED(status))
|
|
sprintf(buf, "WIFSTOPPED,sig=%s", signame(WSTOPSIG(status)));
|
|
#ifdef WIFCONTINUED
|
|
if (WIFCONTINUED(status))
|
|
strcpy(buf, "WIFCONTINUED");
|
|
#endif
|
|
evbuf[0] = '\0';
|
|
if (event != 0) {
|
|
static const char *const event_names[] = {
|
|
[PTRACE_EVENT_CLONE] = "CLONE",
|
|
[PTRACE_EVENT_FORK] = "FORK",
|
|
[PTRACE_EVENT_VFORK] = "VFORK",
|
|
[PTRACE_EVENT_VFORK_DONE] = "VFORK_DONE",
|
|
[PTRACE_EVENT_EXEC] = "EXEC",
|
|
[PTRACE_EVENT_EXIT] = "EXIT",
|
|
};
|
|
const char *e;
|
|
if (event < ARRAY_SIZE(event_names))
|
|
e = event_names[event];
|
|
else {
|
|
sprintf(buf, "?? (%u)", event);
|
|
e = buf;
|
|
}
|
|
sprintf(evbuf, ",PTRACE_EVENT_%s", e);
|
|
}
|
|
fprintf(stderr, " [wait(0x%04x) = %u] %s%s\n", status, pid, buf, evbuf);
|
|
}
|
|
|
|
/* Look up 'pid' in our table. */
|
|
tcp = pid2tcb(pid);
|
|
|
|
if (!tcp) {
|
|
if (followfork) {
|
|
tcp = alloctcb(pid);
|
|
tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
|
|
newoutf(tcp);
|
|
if (!qflag)
|
|
fprintf(stderr, "Process %d attached\n",
|
|
pid);
|
|
} else {
|
|
/* This can happen if a clone call used
|
|
CLONE_PTRACE itself. */
|
|
if (WIFSTOPPED(status))
|
|
ptrace(PTRACE_CONT, pid, (char *) 0, 0);
|
|
error_msg_and_die("Unknown pid: %u", pid);
|
|
}
|
|
}
|
|
|
|
clear_regs();
|
|
if (WIFSTOPPED(status))
|
|
get_regs(pid);
|
|
|
|
/* Under Linux, execve changes pid to thread leader's pid,
|
|
* and we see this changed pid on EVENT_EXEC and later,
|
|
* execve sysexit. Leader "disappears" without exit
|
|
* notification. Let user know that, drop leader's tcb,
|
|
* and fix up pid in execve thread's tcb.
|
|
* Effectively, execve thread's tcb replaces leader's tcb.
|
|
*
|
|
* BTW, leader is 'stuck undead' (doesn't report WIFEXITED
|
|
* on exit syscall) in multithreaded programs exactly
|
|
* in order to handle this case.
|
|
*
|
|
* PTRACE_GETEVENTMSG returns old pid starting from Linux 3.0.
|
|
* On 2.6 and earlier, it can return garbage.
|
|
*/
|
|
if (event == PTRACE_EVENT_EXEC && os_release >= KERNEL_VERSION(3,0,0)) {
|
|
FILE *fp;
|
|
struct tcb *execve_thread;
|
|
long old_pid = 0;
|
|
|
|
if (ptrace(PTRACE_GETEVENTMSG, pid, NULL, (long) &old_pid) < 0)
|
|
goto dont_switch_tcbs;
|
|
if (old_pid <= 0 || old_pid == pid)
|
|
goto dont_switch_tcbs;
|
|
execve_thread = pid2tcb(old_pid);
|
|
/* It should be !NULL, but I feel paranoid */
|
|
if (!execve_thread)
|
|
goto dont_switch_tcbs;
|
|
|
|
if (execve_thread->curcol != 0) {
|
|
/*
|
|
* One case we are here is -ff:
|
|
* try "strace -oLOG -ff test/threaded_execve"
|
|
*/
|
|
fprintf(execve_thread->outf, " <pid changed to %d ...>\n", pid);
|
|
/*execve_thread->curcol = 0; - no need, see code below */
|
|
}
|
|
/* Swap output FILEs (needed for -ff) */
|
|
fp = execve_thread->outf;
|
|
execve_thread->outf = tcp->outf;
|
|
tcp->outf = fp;
|
|
/* And their column positions */
|
|
execve_thread->curcol = tcp->curcol;
|
|
tcp->curcol = 0;
|
|
/* Drop leader, but close execve'd thread outfile (if -ff) */
|
|
droptcb(tcp);
|
|
/* Switch to the thread, reusing leader's outfile and pid */
|
|
tcp = execve_thread;
|
|
tcp->pid = pid;
|
|
if (cflag != CFLAG_ONLY_STATS) {
|
|
printleader(tcp);
|
|
tprintf("+++ superseded by execve in pid %lu +++\n", old_pid);
|
|
line_ended();
|
|
tcp->flags |= TCB_REPRINT;
|
|
}
|
|
}
|
|
dont_switch_tcbs:
|
|
|
|
if (event == PTRACE_EVENT_EXEC) {
|
|
if (detach_on_execve && !skip_one_b_execve)
|
|
detach(tcp); /* do "-b execve" thingy */
|
|
skip_one_b_execve = 0;
|
|
}
|
|
|
|
/* Set current output file */
|
|
current_tcp = tcp;
|
|
|
|
if (cflag) {
|
|
tv_sub(&tcp->dtime, &ru.ru_stime, &tcp->stime);
|
|
tcp->stime = ru.ru_stime;
|
|
}
|
|
|
|
if (WIFSIGNALED(status)) {
|
|
if (pid == strace_child)
|
|
exit_code = 0x100 | WTERMSIG(status);
|
|
if (cflag != CFLAG_ONLY_STATS
|
|
&& (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)
|
|
) {
|
|
printleader(tcp);
|
|
#ifdef WCOREDUMP
|
|
tprintf("+++ killed by %s %s+++\n",
|
|
signame(WTERMSIG(status)),
|
|
WCOREDUMP(status) ? "(core dumped) " : "");
|
|
#else
|
|
tprintf("+++ killed by %s +++\n",
|
|
signame(WTERMSIG(status)));
|
|
#endif
|
|
line_ended();
|
|
}
|
|
droptcb(tcp);
|
|
continue;
|
|
}
|
|
if (WIFEXITED(status)) {
|
|
if (pid == strace_child)
|
|
exit_code = WEXITSTATUS(status);
|
|
if (cflag != CFLAG_ONLY_STATS &&
|
|
qflag < 2) {
|
|
printleader(tcp);
|
|
tprintf("+++ exited with %d +++\n", WEXITSTATUS(status));
|
|
line_ended();
|
|
}
|
|
droptcb(tcp);
|
|
continue;
|
|
}
|
|
if (!WIFSTOPPED(status)) {
|
|
fprintf(stderr, "PANIC: pid %u not stopped\n", pid);
|
|
droptcb(tcp);
|
|
continue;
|
|
}
|
|
|
|
/* Is this the very first time we see this tracee stopped? */
|
|
if (tcp->flags & TCB_STARTUP) {
|
|
if (debug_flag)
|
|
fprintf(stderr, "pid %d has TCB_STARTUP, initializing it\n", tcp->pid);
|
|
tcp->flags &= ~TCB_STARTUP;
|
|
if (tcp->flags & TCB_BPTSET) {
|
|
/*
|
|
* One example is a breakpoint inherited from
|
|
* parent through fork().
|
|
*/
|
|
if (clearbpt(tcp) < 0) {
|
|
/* Pretty fatal */
|
|
droptcb(tcp);
|
|
cleanup();
|
|
return -1;
|
|
}
|
|
}
|
|
if (ptrace_setoptions) {
|
|
if (debug_flag)
|
|
fprintf(stderr, "setting opts %x on pid %d\n", ptrace_setoptions, tcp->pid);
|
|
if (ptrace(PTRACE_SETOPTIONS, tcp->pid, NULL, ptrace_setoptions) < 0) {
|
|
if (errno != ESRCH) {
|
|
/* Should never happen, really */
|
|
perror_msg_and_die("PTRACE_SETOPTIONS");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
sig = WSTOPSIG(status);
|
|
|
|
if (event != 0) {
|
|
/* Ptrace event */
|
|
#if USE_SEIZE
|
|
if (event == PTRACE_EVENT_STOP) {
|
|
/*
|
|
* PTRACE_INTERRUPT-stop or group-stop.
|
|
* PTRACE_INTERRUPT-stop has sig == SIGTRAP here.
|
|
*/
|
|
if (sig == SIGSTOP
|
|
|| sig == SIGTSTP
|
|
|| sig == SIGTTIN
|
|
|| sig == SIGTTOU
|
|
) {
|
|
stopped = 1;
|
|
goto show_stopsig;
|
|
}
|
|
}
|
|
#endif
|
|
goto restart_tracee_with_sig_0;
|
|
}
|
|
|
|
/* Is this post-attach SIGSTOP?
|
|
* Interestingly, the process may stop
|
|
* with STOPSIG equal to some other signal
|
|
* than SIGSTOP if we happend to attach
|
|
* just before the process takes a signal.
|
|
*/
|
|
if (sig == SIGSTOP && (tcp->flags & TCB_IGNORE_ONE_SIGSTOP)) {
|
|
if (debug_flag)
|
|
fprintf(stderr, "ignored SIGSTOP on pid %d\n", tcp->pid);
|
|
tcp->flags &= ~TCB_IGNORE_ONE_SIGSTOP;
|
|
goto restart_tracee_with_sig_0;
|
|
}
|
|
|
|
if (sig != syscall_trap_sig) {
|
|
siginfo_t si;
|
|
|
|
/* Nonzero (true) if tracee is stopped by signal
|
|
* (as opposed to "tracee received signal").
|
|
* TODO: shouldn't we check for errno == EINVAL too?
|
|
* We can get ESRCH instead, you know...
|
|
*/
|
|
stopped = (ptrace(PTRACE_GETSIGINFO, pid, 0, (long) &si) < 0);
|
|
#if USE_SEIZE
|
|
show_stopsig:
|
|
#endif
|
|
if (cflag != CFLAG_ONLY_STATS
|
|
&& !hide_log_until_execve
|
|
&& (qual_flags[sig] & QUAL_SIGNAL)
|
|
) {
|
|
#if defined(PT_CR_IPSR) && defined(PT_CR_IIP)
|
|
long pc = 0;
|
|
long psr = 0;
|
|
|
|
upeek(tcp, PT_CR_IPSR, &psr);
|
|
upeek(tcp, PT_CR_IIP, &pc);
|
|
|
|
# define PSR_RI 41
|
|
pc += (psr >> PSR_RI) & 0x3;
|
|
# define PC_FORMAT_STR " @ %lx"
|
|
# define PC_FORMAT_ARG , pc
|
|
#else
|
|
# define PC_FORMAT_STR ""
|
|
# define PC_FORMAT_ARG /* nothing */
|
|
#endif
|
|
printleader(tcp);
|
|
if (!stopped) {
|
|
tprintf("--- %s ", signame(sig));
|
|
printsiginfo(&si, verbose(tcp));
|
|
tprintf(PC_FORMAT_STR " ---\n"
|
|
PC_FORMAT_ARG);
|
|
} else
|
|
tprintf("--- stopped by %s" PC_FORMAT_STR " ---\n",
|
|
signame(sig)
|
|
PC_FORMAT_ARG);
|
|
line_ended();
|
|
}
|
|
|
|
if (!stopped)
|
|
/* It's signal-delivery-stop. Inject the signal */
|
|
goto restart_tracee;
|
|
|
|
/* It's group-stop */
|
|
if (use_seize) {
|
|
/*
|
|
* This ends ptrace-stop, but does *not* end group-stop.
|
|
* This makes stopping signals work properly on straced process
|
|
* (that is, process really stops. It used to continue to run).
|
|
*/
|
|
if (ptrace_restart(PTRACE_LISTEN, tcp, 0) < 0) {
|
|
cleanup();
|
|
return -1;
|
|
}
|
|
continue;
|
|
}
|
|
/* We don't have PTRACE_LISTEN support... */
|
|
goto restart_tracee;
|
|
}
|
|
|
|
/* We handled quick cases, we are permitted to interrupt now. */
|
|
if (interrupted)
|
|
return 0;
|
|
|
|
/* This should be syscall entry or exit.
|
|
* (Or it still can be that pesky post-execve SIGTRAP!)
|
|
* Handle it.
|
|
*/
|
|
if (trace_syscall(tcp) < 0) {
|
|
/* ptrace() failed in trace_syscall().
|
|
* Likely a result of process disappearing mid-flight.
|
|
* Observed case: exit_group() or SIGKILL terminating
|
|
* all processes in thread group.
|
|
* We assume that ptrace error was caused by process death.
|
|
* We used to detach(tcp) here, but since we no longer
|
|
* implement "detach before death" policy/hack,
|
|
* we can let this process to report its death to us
|
|
* normally, via WIFEXITED or WIFSIGNALED wait status.
|
|
*/
|
|
continue;
|
|
}
|
|
restart_tracee_with_sig_0:
|
|
sig = 0;
|
|
restart_tracee:
|
|
if (ptrace_restart(PTRACE_SYSCALL, tcp, sig) < 0) {
|
|
cleanup();
|
|
return -1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
init(argc, argv);
|
|
|
|
/* Run main tracing loop */
|
|
if (trace() < 0)
|
|
return 1;
|
|
|
|
cleanup();
|
|
fflush(NULL);
|
|
if (shared_log != stderr)
|
|
fclose(shared_log);
|
|
if (popen_pid) {
|
|
while (waitpid(popen_pid, NULL, 0) < 0 && errno == EINTR)
|
|
;
|
|
}
|
|
if (exit_code > 0xff) {
|
|
/* Avoid potential core file clobbering. */
|
|
struct_rlimit rlim = {0, 0};
|
|
set_rlimit(RLIMIT_CORE, &rlim);
|
|
|
|
/* Child was killed by a signal, mimic that. */
|
|
exit_code &= 0xff;
|
|
signal(exit_code, SIG_DFL);
|
|
raise(exit_code);
|
|
/* Paranoia - what if this signal is not fatal?
|
|
Exit with 128 + signo then. */
|
|
exit_code += 128;
|
|
}
|
|
|
|
return exit_code;
|
|
}
|