Dmitry V. Levin
e83e157021
Suppress repeated empty lines left after automated code removal. This change was made by filtering every source code file through "cat -s".
369 lines
8.3 KiB
C
369 lines
8.3 KiB
C
/*
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* Copyright (c) 2011, Comtrol Corp.
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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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*/
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#include "defs.h"
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#include <ctype.h>
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#include <sys/param.h>
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#ifdef HAVE_POLL_H
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#include <poll.h>
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#endif
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#ifdef HAVE_SYS_POLL_H
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#include <sys/poll.h>
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#endif
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#include "syscall.h"
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#define MAXSELECTED 256 /* max number of "selected" paths */
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static const char *selected[MAXSELECTED]; /* paths selected for tracing */
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/*
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* Return true if specified path matches one that we're tracing.
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*/
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static int
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pathmatch(const char *path)
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{
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(selected); ++i) {
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if (selected[i] == NULL)
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return 0;
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if (!strcmp(path, selected[i]))
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return 1;
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}
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return 0;
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}
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/*
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* Return true if specified path (in user-space) matches.
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*/
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static int
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upathmatch(struct tcb *tcp, unsigned long upath)
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{
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char path[PATH_MAX + 1];
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return umovestr(tcp, upath, sizeof path, path) >= 0 &&
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pathmatch(path);
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}
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/*
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* Return true if specified fd maps to a path we're tracing.
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*/
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static int
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fdmatch(struct tcb *tcp, int fd)
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{
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const char *path = getfdpath(tcp, fd);
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return path && pathmatch(path);
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}
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/*
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* Add a path to the set we're tracing.
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* Secifying NULL will delete all paths.
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*/
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static int
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storepath(const char *path)
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{
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unsigned int i;
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if (path == NULL) {
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for (i = 0; i < ARRAY_SIZE(selected); ++i)
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if (selected[i]) {
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free((char *) selected[i]);
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selected[i] = NULL;
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}
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return 0;
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}
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for (i = 0; i < ARRAY_SIZE(selected); ++i)
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if (!selected[i]) {
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selected[i] = path;
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return 0;
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}
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fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
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(unsigned int) ARRAY_SIZE(selected));
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return -1;
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}
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/*
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* Get path associated with fd.
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*/
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const char *getfdpath(struct tcb *tcp, int fd)
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{
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static char path[PATH_MAX+1];
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char linkpath[64];
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ssize_t n;
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if (fd < 0)
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return NULL;
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snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
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n = readlink(linkpath, path, (sizeof path) - 1);
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if (n <= 0)
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return NULL;
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path[n] = '\0';
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return path;
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}
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/*
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* Add a path to the set we're tracing. Also add the canonicalized
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* version of the path. Secifying NULL will delete all paths.
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*/
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int
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pathtrace_select(const char *path)
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{
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char *rpath;
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if (path == NULL)
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return storepath(path);
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if (storepath(path))
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return -1;
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rpath = realpath(path, NULL);
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if (rpath == NULL)
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return 0;
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/* if realpath and specified path are same, we're done */
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if (!strcmp(path, rpath)) {
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free(rpath);
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return 0;
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}
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fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
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path, rpath);
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return storepath(rpath);
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}
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/*
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* Return true if syscall accesses a selected path
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* (or if no paths have been specified for tracing).
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*/
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int
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pathtrace_match(struct tcb *tcp)
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{
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const struct sysent *s;
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if (selected[0] == NULL)
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return 1;
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if (!SCNO_IN_RANGE(tcp->scno))
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return 0;
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s = &sysent[tcp->scno];
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if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
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return 0;
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/*
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* Check for special cases where we need to do something
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* other than test arg[0].
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*/
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if (s->sys_func == sys_dup2 ||
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s->sys_func == sys_dup3 ||
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s->sys_func == sys_sendfile ||
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s->sys_func == sys_sendfile64 ||
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s->sys_func == sys_tee)
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{
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/* fd, fd */
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return fdmatch(tcp, tcp->u_arg[0]) ||
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fdmatch(tcp, tcp->u_arg[1]);
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}
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if (s->sys_func == sys_inotify_add_watch ||
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s->sys_func == sys_faccessat ||
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s->sys_func == sys_fchmodat ||
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s->sys_func == sys_futimesat ||
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s->sys_func == sys_mkdirat ||
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s->sys_func == sys_unlinkat ||
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s->sys_func == sys_newfstatat ||
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s->sys_func == sys_mknodat ||
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s->sys_func == sys_openat ||
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s->sys_func == sys_readlinkat ||
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s->sys_func == sys_utimensat ||
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s->sys_func == sys_fchownat ||
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s->sys_func == sys_pipe2)
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{
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/* fd, path */
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return fdmatch(tcp, tcp->u_arg[0]) ||
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upathmatch(tcp, tcp->u_arg[1]);
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}
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if (s->sys_func == sys_link ||
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s->sys_func == sys_mount)
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{
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/* path, path */
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return upathmatch(tcp, tcp->u_arg[0]) ||
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upathmatch(tcp, tcp->u_arg[1]);
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}
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if (s->sys_func == sys_renameat ||
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s->sys_func == sys_linkat)
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{
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/* fd, path, fd, path */
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return fdmatch(tcp, tcp->u_arg[0]) ||
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fdmatch(tcp, tcp->u_arg[2]) ||
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upathmatch(tcp, tcp->u_arg[1]) ||
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upathmatch(tcp, tcp->u_arg[3]);
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}
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if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap) {
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/* x, x, x, x, fd */
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return fdmatch(tcp, tcp->u_arg[4]);
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}
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if (s->sys_func == sys_symlinkat) {
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/* path, fd, path */
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return fdmatch(tcp, tcp->u_arg[1]) ||
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upathmatch(tcp, tcp->u_arg[0]) ||
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upathmatch(tcp, tcp->u_arg[2]);
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}
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if (s->sys_func == sys_splice) {
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/* fd, x, fd, x, x */
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return fdmatch(tcp, tcp->u_arg[0]) ||
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fdmatch(tcp, tcp->u_arg[2]);
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}
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if (s->sys_func == sys_epoll_ctl) {
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/* x, x, fd, x */
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return fdmatch(tcp, tcp->u_arg[2]);
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}
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if (s->sys_func == sys_select ||
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s->sys_func == sys_oldselect ||
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s->sys_func == sys_pselect6)
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{
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int i, j;
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unsigned nfds;
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long *args, oldargs[5];
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unsigned fdsize;
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fd_set *fds;
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if (s->sys_func == sys_oldselect) {
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if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
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(char*) oldargs) < 0)
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{
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fprintf(stderr, "umoven() failed\n");
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return 0;
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}
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args = oldargs;
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} else
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args = tcp->u_arg;
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nfds = args[0];
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/* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
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if (args[0] > 1024*1024)
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nfds = 1024*1024;
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if (args[0] < 0)
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nfds = 0;
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fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
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& -sizeof(long));
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fds = malloc(fdsize);
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if (!fds)
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die_out_of_memory();
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for (i = 1; i <= 3; ++i) {
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if (args[i] == 0)
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continue;
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if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
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fprintf(stderr, "umoven() failed\n");
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continue;
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}
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for (j = 0; j < nfds; ++j)
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if (FD_ISSET(j, fds) && fdmatch(tcp, j)) {
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free(fds);
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return 1;
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}
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}
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free(fds);
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return 0;
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}
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if (s->sys_func == sys_poll ||
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s->sys_func == sys_ppoll)
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{
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struct pollfd fds;
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unsigned nfds;
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unsigned long start, cur, end;
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start = tcp->u_arg[0];
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nfds = tcp->u_arg[1];
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end = start + sizeof(fds) * nfds;
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if (nfds == 0 || end < start)
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return 0;
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for (cur = start; cur < end; cur += sizeof(fds))
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if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
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&& fdmatch(tcp, fds.fd))
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return 1;
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return 0;
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}
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if (s->sys_func == printargs ||
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s->sys_func == sys_pipe ||
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s->sys_func == sys_pipe2 ||
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s->sys_func == sys_eventfd2 ||
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s->sys_func == sys_eventfd ||
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s->sys_func == sys_inotify_init1 ||
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s->sys_func == sys_timerfd_create ||
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s->sys_func == sys_timerfd_settime ||
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s->sys_func == sys_timerfd_gettime ||
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s->sys_func == sys_epoll_create ||
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!strcmp(s->sys_name, "fanotify_init"))
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{
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/*
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* These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
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* don't have any file descriptor or path args to test.
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*/
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return 0;
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}
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/*
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* Our fallback position for calls that haven't already
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* been handled is to just check arg[0].
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*/
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if (s->sys_flags & TRACE_FILE)
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return upathmatch(tcp, tcp->u_arg[0]);
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if (s->sys_flags & TRACE_DESC)
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return fdmatch(tcp, tcp->u_arg[0]);
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return 0;
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}
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