From: Bijan Tabatabai <bijan311@xxxxxxxxx>
When the -F flag is used in trace-cmd record, trace-cmd stops recording
when the executable it is tracing terminates.
This patch makes the -P flag act similarly.
Signed-off-by: Bijan Tabatabai <bijan311@xxxxxxxxx>
---
I changed this patch to use the pidfd interface to determine if a process had
ended.
I also refactored the patch a bit, so it looks much cleaner in my opinion.
---
tracecmd/trace-record.c | 81 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index d8c24eb..5b9c961 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -16,6 +16,7 @@
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>
+#include <sys/syscall.h>
#include <sys/utsname.h>
#ifndef NO_PTRACE
#include <sys/ptrace.h>
@@ -33,6 +34,7 @@
#include <errno.h>
#include <limits.h>
#include <libgen.h>
+#include <poll.h>
#include <pwd.h>
#include <grp.h>
#ifdef VSOCK
@@ -121,8 +123,10 @@ struct filter_pids {
};
static struct filter_pids *filter_pids;
+static struct filter_pids *process_pids;
static int nr_filter_pids;
static int len_filter_pids;
+static int nr_process_pids = 0;
static int have_set_event_pid;
static int have_event_fork;
@@ -1243,6 +1247,79 @@ static pid_t trace_waitpid(enum trace_type type, pid_t pid, int *status, int opt
trace_stream_read(pids, recorder_threads, &tv);
} while (1);
}
+
+#ifndef __NR_pidfd_open
+#define __NR_pidfd_open 434
+#endif
+
+static int pidfd_open(pid_t pid, unsigned int flags) {
+ return syscall(__NR_pidfd_open, pid, flags);
+}
+
+static int trace_waitpidfd(id_t pidfd) {
+ struct pollfd pollfd;
+
+ pollfd.fd = pidfd;
+ pollfd.events = POLLIN;
+
+ while (!finished) {
+ int ret = poll(&pollfd, 1, -1);
+ /* If waitid was interrupted, keep waiting */
+ if (ret < 0 && errno == EINTR)
+ continue;
+ else if (ret < 0)
+ return 1;
+ else
+ break;
+ }
+
+ return 0;
+}
+
+static int trace_wait_for_processes() {
+ int ret = 0;
+ int nr_fds = 0;
+ int i;
+ int *pidfds;
+ struct filter_pids *pid;
+
+ pidfds = malloc(sizeof(int) * nr_process_pids);
+ if (!pidfds)
+ return 1;
+
+ for (pid = process_pids; pid && nr_process_pids; pid = pid->next) {
+ if (pid->exclude) {
+ nr_process_pids--;
+ continue;
+ }
+ pidfds[nr_fds] = pidfd_open(pid->pid, 0);
+
+ /* If the pid doesn't exist, the process has probably exited */
+ if (pidfds[nr_fds] < 0 && errno == ESRCH) {
+ nr_process_pids--;
+ continue;
+ } else if (pidfds[nr_fds] < 0) {
+ ret = 1;
+ goto out;
+ }
+
+ nr_fds++;
+ nr_process_pids--;
+ }
+
+ for (i = 0; i < nr_fds; i++) {
+ if (trace_waitpidfd(pidfds[i])) {
+ ret = 1;
+ goto out;
+ }
+ }
+
+out:
+ for (i = 0; i < nr_fds; i++)
+ close(pidfds[i]);
+ free(pidfds);
+ return ret;
+}
#ifndef NO_PTRACE
/**
@@ -5832,7 +5909,9 @@ static void parse_record_options(int argc,
while (pid) {
add_filter_pid(atoi(pid), 0);
pid = strtok_r(NULL, ",", &sav);
+ nr_process_pids++;
}
+ process_pids = filter_pids;
free(pids);
break;
case 'c':
@@ -6308,6 +6387,8 @@ static void record_trace(int argc, char **argv,
}
/* sleep till we are woken with Ctrl^C */
printf("Hit Ctrl^C to stop recording\n");
+ if (nr_process_pids && !trace_wait_for_processes())
+ finished = 1;
while (!finished)
trace_or_sleep(type);
}
--
2.25.1
|