* strace.c (USE_VFORK): New macro, use instead of strace_vforked.
* strace.c (USE_VFORK): Check for uClinux flavours with stub fork
which returns ENOSYS, is found by ./configure, but can't be used.
* strace.c (strace_vforked): Removed.
* strace.c (main): Change strace_vforked reference to USE_VFORK.
It's a bit uglier but as this was the only place where strace_vforked
was notably prettier I decided to remove it.
* strace.c (startup_child): Change error message to say vfork
failed, not fork.
* strace.c (startup_child): Don't call initgroups in a vfork child.
We have to make do without supplementary groups.
* strace.c (daemonized_tracer): Make this constant 0 when using
vfork, and remove it from the options processing and help text.
This makes the help text depend on C89 string concatenation, but
as we dropped non-C89 support some time ago, this should be ok.
Signed-off-by: Jamie Lokier <ja...@shareable.org>
---
strace.c | 75 ++++++++++++++++++++++++++++++++++++++++++++-----------------
1 files changed, 54 insertions(+), 21 deletions(-)
diff --git a/strace.c b/strace.c
index 8b7434f..5b44f1c 100644
--- a/strace.c
+++ b/strace.c
@@ -86,6 +86,21 @@ int debug = 0, followfork = 0;
int dtime = 0, xflag = 0, qflag = 0;
cflag_t cflag = CFLAG_NONE;
static int iflag = 0, interactive = 0, pflag_seen = 0, rflag = 0, tflag = 0;
+
+/* Glue for systems without a MMU that cannot provide fork() */
+#ifdef LINUX
+/* Some uClinux versions have fork() as a stub returning ENOSYS. */
+# if defined __UCLIBC__
+# if !defined __UCLIBC_HAS_MMU__ && !defined __ARCH_HAS_MMU__
+# undef HAVE_FORK
+# endif
+# endif
+#endif
+#ifndef HAVE_FORK
+# define USE_VFORK
+# define fork() vfork()
+#endif
+
/*
* daemonized_tracer supports -D option.
* With this option, strace forks twice.
@@ -98,7 +113,11 @@ static int iflag = 0, interactive = 0, pflag_seen = 0,
rflag = 0, tflag = 0;
* wait() etc. Without -D, strace process gets lodged in between,
* disrupting parent<->child link.
*/
+#ifndef USE_VFORK /* Does not work with vfork. */
static bool daemonized_tracer = 0;
+#else
+# define daemonized_tracer 0
+#endif
/* Sometimes we want to print only succeeding syscalls. */
int not_failing_only = 0;
@@ -187,9 +206,11 @@ usage: strace [-dffhiqrtttTvVxx] [-a column] [-e expr] ...
[-o file]\n\
options: trace, abbrev, verbose, raw, signal, read, or write\n\
-o file -- send trace output to FILE instead of stderr\n\
-O overhead -- set overhead for tracing syscalls to OVERHEAD usecs\n\
--p pid -- trace process with process id PID, may be repeated\n\
--D -- run tracer process as a detached grandchild, not as parent\n\
--s strsize -- limit length of print strings to STRSIZE chars (default %d)\n\
+-p pid -- trace process with process id PID, may be repeated\n"
+#if !defined USE_PROCFS && !defined USE_VFORK
+"-D -- run tracer process as a detached grandchild, not as parent\n"
+#endif
+"-s strsize -- limit length of print strings to STRSIZE chars (default %d)\n\
-S sortby -- sort syscall counts by: time, calls, name, nothing (default %s)\n\
-u username -- run command as username handling setuid and/or setgid\n\
-E var=val -- put var=val in the environment for command\n\
@@ -210,14 +231,6 @@ foobar()
#endif /* MIPS */
#endif /* SVR4 */
-/* Glue for systems without a MMU that cannot provide fork() */
-#ifdef HAVE_FORK
-# define strace_vforked 0
-#else
-# define strace_vforked 1
-# define fork() vfork()
-#endif
-
static int
set_cloexec_flag(int fd)
{
@@ -571,7 +584,11 @@ startup_child (char **argv)
}
strace_child = pid = fork();
if (pid < 0) {
- perror(strace_vforked ? "strace: vfork" : "strace: fork");
+#ifdef USE_VFORK
+ perror("strace: vfork");
+#else
+ perror("strace: fork");
+#endif
cleanup();
exit(1);
}
@@ -602,8 +619,10 @@ startup_child (char **argv)
perror("strace: ptrace(PTRACE_TRACEME, ...)");
exit(1);
}
+#ifndef USE_VFORK
if (debug)
kill(pid, SIGSTOP);
+#endif
}
if (username != NULL || geteuid() == 0) {
@@ -620,12 +639,22 @@ startup_child (char **argv)
* lose privileges on setuid.
*/
if (username != NULL) {
- /* initgroups is not safe in a vfork child. */
- if (!strace_vforked
- && initgroups(username, run_gid) < 0) {
+#ifndef USE_VFORK
+ if (initgroups(username, run_gid) < 0) {
perror("initgroups");
exit(1);
}
+#else /* vfork */
+ /*
+ * initgroups is not safe in a vfork child
+ * because it parses /etc/group.
+ */
+ if (setgroups(0, (const gid_t *)NULL) < 0) {
+ perror("setgroups");
+ exit(1);
+ }
+#endif /* vfork */
+
if (setregid(run_gid, run_egid) < 0) {
perror("setregid");
exit(1);
@@ -647,8 +676,9 @@ startup_child (char **argv)
* Unless of course we're on a no-MMU system where
* we vfork()-ed, so we cannot stop the child.
*/
- if (!strace_vforked)
- kill(getpid(), SIGSTOP);
+#ifndef USE_VFORK
+ kill(getpid(), SIGSTOP);
+#endif
} else {
struct sigaction sv_sigchld;
sigaction(SIGCHLD, NULL, &sv_sigchld);
@@ -723,7 +753,7 @@ main(int argc, char *argv[])
qualify("signal=all");
while ((c = getopt(argc, argv,
"+cCdfFhiqrtTvVxz"
-#ifndef USE_PROCFS
+#if !defined USE_PROCFS && !defined USE_VFORK
"D"
#endif
"a:e:o:O:p:s:S:u:E:")) != EOF) {
@@ -747,7 +777,7 @@ main(int argc, char *argv[])
case 'd':
debug++;
break;
-#ifndef USE_PROCFS
+#if !defined USE_PROCFS && !defined USE_VFORK
/* Experimental, not documented in manpage yet. */
case 'D':
daemonized_tracer = 1;
@@ -2463,8 +2493,11 @@ Process %d attached (waiting for parent)\n",
* A no-MMU vforked child won't send up a signal,
* so skip the first (lost) execve notification.
*/
- if ((tcp->flags & TCB_STARTUP) &&
- (WSTOPSIG(status) == SIGSTOP || strace_vforked)) {
+ if ((tcp->flags & TCB_STARTUP)
+#ifndef USE_VFORK
+ && WSTOPSIG(status) == SIGSTOP
+#endif
+ ) {
/*
* This flag is there to keep us in sync.
* Next time this process stops it should
--
1.7.0.4
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