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Assorted NOMMU fixes

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With -D, strdup'ing of pathname is necessary only on NOMMU.

Don't set skip_startup_execve to 1 if NOMMU and not in daemonized mode
(try "strace [-D] -b env echo HI" to see whether we detach on correct execve).

Fix test_ptrace_FOO shortcuts on NOMMU to always assume success
and _properly_ set all variables.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2013-02-26 12:00:34 +01:00
parent 38e79bbb25
commit 05f325199a
2 changed files with 17 additions and 7 deletions
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2
defs.h
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@ -116,7 +116,7 @@ extern char *stpcpy(char *dst, const char *src);
* This needs Linux kernel 3.4.x or later to work.
*/
#define USE_SEIZE 1
/* For forcing NOMMU build, set to 1 */
/* To force NOMMU build, set to 1 */
#define NOMMU_SYSTEM 0

22
strace.c
View File

@ -1122,7 +1122,7 @@ startup_child(char **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 = strdup(pathname);
params_for_tracee.pathname = NOMMU_SYSTEM ? strdup(pathname) : pathname;
strace_child = pid = fork();
if (pid < 0) {
@ -1156,6 +1156,7 @@ startup_child(char **argv)
kill_save_errno(pid, SIGKILL);
perror_msg_and_die("Unexpected wait status %x", status);
}
skip_startup_execve = 1;
}
/* Else: NOMMU case, we have no way to sync.
* Just attach to it as soon as possible.
@ -1177,13 +1178,14 @@ startup_child(char **argv)
newoutf(tcp);
}
else {
/* With -D, *we* are child here, IOW: different pid. Fetch it: */
/* 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! */
skip_startup_execve = 1;
/* NOMMU BUG! -D mode is active, we (child) return,
* and we will scribble over parent's stack!
@ -1201,6 +1203,9 @@ startup_child(char **argv)
* 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.
*/
}
}
@ -1218,6 +1223,10 @@ test_ptrace_setoptions_followfork(void)
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");
@ -1299,6 +1308,7 @@ test_ptrace_setoptions_followfork(void)
}
}
if (expected_grandchild && expected_grandchild == found_grandchild) {
worked:
ptrace_setoptions |= test_options;
if (debug_flag)
fprintf(stderr, "ptrace_setoptions = %#x\n",
@ -1332,9 +1342,9 @@ test_ptrace_setoptions_for_all(void)
int pid;
int it_worked = 0;
/* this fork test doesn't work on no-mmu systems */
/* Need fork for test. NOMMU has no forks */
if (NOMMU_SYSTEM)
return 0; /* be bold, and pretend that test succeeded */
goto worked; /* be bold, and pretend that test succeeded */
pid = fork();
if (pid < 0)
@ -1398,6 +1408,7 @@ test_ptrace_setoptions_for_all(void)
}
if (it_worked) {
worked:
syscall_trap_sig = (SIGTRAP | 0x80);
ptrace_setoptions |= test_options;
if (debug_flag)
@ -1417,7 +1428,7 @@ test_ptrace_seize(void)
{
int pid;
/* this fork test doesn't work on no-mmu systems */
/* Need fork for test. NOMMU has no forks */
if (NOMMU_SYSTEM) {
post_attach_sigstop = 0; /* this sets use_seize to 1 */
return;
@ -1770,7 +1781,6 @@ init(int argc, char *argv[])
* in the startup_child() mode we kill the spawned process anyway.
*/
if (argv[0]) {
skip_startup_execve = 1;
startup_child(argv);
}