/* Are we "strace PROG" and need to hide everything until execve? */
bool hide_log_until_execve = 0;
-static int exit_code = 0;
+static int exit_code;
static int strace_child = 0;
static int strace_tracer_pid = 0;
#endif /* HAVE_STERRROR */
static void
-usage()
+usage(void)
{
printf("\
usage: strace [-CdffhiqrtttTvVwxxy] [-I n] [-e expr]...\n\
-x print non-ascii strings in hex\n\
-xx print all strings in hex\n\
-y print paths associated with file descriptor arguments\n\
- -yy print ip:port pairs associated with socket file descriptors\n\
+ -yy print protocol specific information associated with socket file descriptors\n\
\n\
Statistics:\n\
-c count time, calls, and errors for each syscall and report summary\n\
error_msg_and_help("invalid -%c argument: '%s'", opt, arg);
}
-#if USE_SEIZE
+static const char *ptrace_attach_cmd;
+
static int
ptrace_attach_or_seize(int pid)
{
+#if USE_SEIZE
int r;
if (!use_seize)
- return ptrace(PTRACE_ATTACH, pid, 0L, 0L);
+ return ptrace_attach_cmd = "PTRACE_ATTACH",
+ ptrace(PTRACE_ATTACH, pid, 0L, 0L);
r = ptrace(PTRACE_SEIZE, pid, 0L, (unsigned long) ptrace_setoptions);
if (r)
- return r;
+ return ptrace_attach_cmd = "PTRACE_SEIZE", r;
r = ptrace(PTRACE_INTERRUPT, pid, 0L, 0L);
- return r;
-}
+ return ptrace_attach_cmd = "PTRACE_INTERRUPT", r;
#else
-# define ptrace_attach_or_seize(pid) ptrace(PTRACE_ATTACH, (pid), 0, 0)
+ return ptrace_attach_cmd = "PTRACE_ATTACH",
+ ptrace(PTRACE_ATTACH, pid, 0L, 0L);
#endif
+}
/*
* Used when we want to unblock stopped traced process.
msg = "CONT";
if (op == PTRACE_DETACH)
msg = "DETACH";
-#ifdef PTRACE_LISTEN
if (op == PTRACE_LISTEN)
msg = "LISTEN";
-#endif
/*
* Why curcol != 0? Otherwise sometimes we get this:
*
fcntl(fd, F_SETFD, newflags); /* never fails */
}
-static void kill_save_errno(pid_t pid, int sig)
+static void
+kill_save_errno(pid_t pid, int sig)
{
int saved_errno = errno;
error_msg_and_die("bug in alloctcb");
}
+void *
+get_tcb_priv_data(const struct tcb *tcp)
+{
+ return tcp->_priv_data;
+}
+
+int
+set_tcb_priv_data(struct tcb *tcp, void *const priv_data,
+ void (*const free_priv_data)(void *))
+{
+ if (tcp->_priv_data)
+ return -1;
+
+ tcp->_free_priv_data = free_priv_data;
+ tcp->_priv_data = priv_data;
+
+ return 0;
+}
+
+void
+free_tcb_priv_data(struct tcb *tcp)
+{
+ if (tcp->_priv_data) {
+ if (tcp->_free_priv_data) {
+ tcp->_free_priv_data(tcp->_priv_data);
+ tcp->_free_priv_data = NULL;
+ }
+ tcp->_priv_data = NULL;
+ }
+}
+
static void
droptcb(struct tcb *tcp)
{
if (tcp->pid == 0)
return;
+ free_tcb_priv_data(tcp);
+
#ifdef USE_LIBUNWIND
if (stack_trace_enabled) {
unwind_tcb_fin(tcp);
* 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
if (!(tcp->flags & TCB_ATTACHED))
goto drop;
}
}
+static void
+attach_tcb(struct tcb *const tcp)
+{
+ if (ptrace_attach_or_seize(tcp->pid) < 0) {
+ perror_msg("attach: ptrace(%s, %d)",
+ ptrace_attach_cmd, tcp->pid);
+ droptcb(tcp);
+ return;
+ }
+
+ tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
+ newoutf(tcp);
+ if (debug_flag)
+ error_msg("attach to pid %d (main) succeeded", tcp->pid);
+
+ char procdir[sizeof("/proc/%d/task") + sizeof(int) * 3];
+ DIR *dir;
+ unsigned int ntid = 0, nerr = 0;
+
+ if (followfork && tcp->pid != strace_child &&
+ sprintf(procdir, "/proc/%d/task", tcp->pid) > 0 &&
+ (dir = opendir(procdir)) != NULL) {
+ struct_dirent *de;
+
+ while ((de = read_dir(dir)) != NULL) {
+ if (de->d_fileno == 0)
+ continue;
+
+ int tid = string_to_uint(de->d_name);
+ if (tid <= 0 || tid == tcp->pid)
+ continue;
+
+ ++ntid;
+ if (ptrace_attach_or_seize(tid) < 0) {
+ ++nerr;
+ if (debug_flag)
+ perror_msg("attach: ptrace(%s, %d)",
+ ptrace_attach_cmd, tid);
+ continue;
+ }
+ if (debug_flag)
+ error_msg("attach to pid %d succeeded", tid);
+
+ struct tcb *tid_tcp = alloctcb(tid);
+ tid_tcp->flags |= TCB_ATTACHED | TCB_STARTUP |
+ post_attach_sigstop;
+ newoutf(tid_tcp);
+ }
+
+ closedir(dir);
+ }
+
+ if (!qflag) {
+ if (ntid > nerr)
+ error_msg("Process %u attached"
+ " with %u threads",
+ tcp->pid, ntid - nerr + 1);
+ else
+ error_msg("Process %u attached",
+ tcp->pid);
+ }
+}
+
static void
startup_attach(void)
{
if (tcp->pid == parent_pid || tcp->pid == strace_tracer_pid) {
errno = EPERM;
- perror_msg("attach: %d", tcp->pid);
+ perror_msg("attach: pid %d", tcp->pid);
droptcb(tcp);
continue;
}
- if (followfork && tcp->pid != strace_child) {
- 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;
+ attach_tcb(tcp);
- 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)
- error_msg("attach to pid %d failed", tid);
- continue;
- }
- if (debug_flag)
- error_msg("attach to pid %d succeeded", 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) {
- if (ntid > 1)
- error_msg("Process %u attached"
- " with %u threads",
- tcp->pid, ntid);
- else
- error_msg("Process %u attached",
- tcp->pid);
- }
- 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;
+ if (interactive) {
+ sigprocmask(SIG_SETMASK, &empty_set, NULL);
+ if (interrupted)
+ goto ret;
+ sigprocmask(SIG_BLOCK, &blocked_set, NULL);
}
- tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
- newoutf(tcp);
- if (debug_flag)
- error_msg("attach to pid %d (main) succeeded", tcp->pid);
-
- if (!qflag)
- error_msg("Process %u attached", tcp->pid);
} /* for each tcbtab[] */
if (daemonized_tracer) {
perror_msg_and_die("exec");
}
+/*
+ * Open a dummy descriptor for use as a placeholder.
+ * The descriptor is O_RDONLY with FD_CLOEXEC flag set.
+ * A read attempt from such descriptor ends with EOF,
+ * a write attempt is rejected with EBADF.
+ */
static int
open_dummy_desc(void)
{
if (pipe(fds))
perror_msg_and_die("pipe");
close(fds[1]);
+ set_cloexec_flag(fds[0]);
return fds[0];
}
+/* placeholder fds status for stdin and stdout */
+static bool fd_is_placeholder[2];
+
+/*
+ * Ensure that all standard file descriptors are open by opening placeholder
+ * file descriptors for those standard file descriptors that are not open.
+ *
+ * The information which descriptors have been made open is saved
+ * in fd_is_placeholder for later use.
+ */
+static void
+ensure_standard_fds_opened(void)
+{
+ int fd;
+
+ while ((fd = open_dummy_desc()) <= 2) {
+ if (fd == 2)
+ break;
+ fd_is_placeholder[fd] = true;
+ }
+
+ if (fd > 2)
+ close(fd);
+}
+
+/*
+ * Redirect stdin and stdout unless they have been opened earlier
+ * by ensure_standard_fds_opened as placeholders.
+ */
+static void
+redirect_standard_fds(void)
+{
+ int i;
+
+ /*
+ * It might be a good idea to redirect stderr as well,
+ * but we sometimes need to print error messages.
+ */
+ for (i = 0; i <= 1; ++i) {
+ if (!fd_is_placeholder[i]) {
+ close(i);
+ open_dummy_desc();
+ }
+ }
+}
+
static void
startup_child(char **argv)
{
if (ptrace_attach_or_seize(pid)) {
kill_save_errno(pid, SIGKILL);
- perror_msg_and_die("Can't attach to %d", pid);
+ perror_msg_and_die("attach: ptrace(%s, %d)",
+ ptrace_attach_cmd, pid);
}
if (!NOMMU_SYSTEM)
kill(pid, SIGCONT);
* the pipe is still open, it has a reader. Thus, "head" will not get its
* SIGPIPE at once, on the first write.
*
- * Preventing it by closing strace's stdin/out.
+ * Preventing it by redirecting strace's stdin/out.
* (Don't leave fds 0 and 1 closed, this is bad practice: future opens
* will reuse them, unexpectedly making a newly opened object "stdin").
*/
- close(0);
- open_dummy_desc(); /* opens to fd#0 */
- dup2(0, 1);
-#if 0
- /* A good idea too, but we sometimes need to print error messages */
- if (shared_log != stderr)
- dup2(0, 2);
-#endif
+ redirect_standard_fds();
}
#if USE_SEIZE
error_msg("ptrace_setoptions = %#x", ptrace_setoptions);
test_ptrace_seize();
- if (fcntl(0, F_GETFD) == -1 || fcntl(1, F_GETFD) == -1) {
- /*
- * Something weird with our stdin and/or stdout -
- * for example, may be not open? In this case,
- * ensure that none of the future opens uses them.
- *
- * This was seen in the wild when /proc/sys/kernel/core_pattern
- * was set to "|/bin/strace -o/tmp/LOG PROG":
- * kernel runs coredump helper with fd#0 open but fd#1 closed (!),
- * therefore LOG gets opened to fd#1, and fd#1 is closed by
- * "don't hold up stdin/out open" code soon after.
- */
- int fd = open_dummy_desc();
- while (fd >= 0 && fd < 2)
- fd = dup(fd);
- if (fd > 2)
- close(fd);
- }
+ /*
+ * Is something weird with our stdin and/or stdout -
+ * for example, may they be not open? In this case,
+ * ensure that none of the future opens uses them.
+ *
+ * This was seen in the wild when /proc/sys/kernel/core_pattern
+ * was set to "|/bin/strace -o/tmp/LOG PROG":
+ * kernel runs coredump helper with fd#0 open but fd#1 closed (!),
+ * therefore LOG gets opened to fd#1, and fd#1 is closed by
+ * "don't hold up stdin/out open" code soon after.
+ */
+ ensure_standard_fds_opened();
/* Check if they want to redirect the output. */
if (outfname) {
/* This can happen if a clone call used
* CLONE_PTRACE itself.
*/
- ptrace(PTRACE_CONT, pid, (char *) 0, 0);
+ ptrace(PTRACE_CONT, pid, NULL, 0);
error_msg("Stop of unknown pid %u seen, PTRACE_CONTed it", pid);
return NULL;
}
printleader(tcp);
if (si) {
tprintf("--- %s ", signame(sig));
- printsiginfo(si, verbose(tcp));
+ printsiginfo(si);
tprints(" ---\n");
} else
tprintf("--- stopped by %s ---\n", signame(sig));
{
init(argc, argv);
+ exit_code = !nprocs;
+
while (trace())
;
projects / strace / blobdiff