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>
---
This patch has changed to use the pidfd interface to determine if a process
has ended.
It also has changed to work with the patch "trace-cmd: Handle filtered PIDs per
ftarce instance" (5502bcef0f962cda).
---
tracecmd/include/trace-local.h | 2 +
tracecmd/trace-record.c | 84 ++++++++++++++++++++++++++++++++++
2 files changed, 86 insertions(+)
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 4c6a63d..5d58550 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -215,9 +215,11 @@ struct buffer_instance {
struct opt_list *options;
struct filter_pids *filter_pids;
+ struct filter_pids *process_pids;
char *common_pid_filter;
int nr_filter_pids;
int len_filter_pids;
+ int nr_process_pids;
bool ptrace_child;
int have_set_event_pid;
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index d0619ba..51e9103 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
@@ -1230,6 +1232,81 @@ 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(struct buffer_instance *instance) {
+ int ret = 0;
+ int nr_fds = 0;
+ int i;
+ int *pidfds;
+ struct filter_pids *pid;
+
+ pidfds = malloc(sizeof(int) * instance->nr_process_pids);
+ if (!pidfds)
+ return 1;
+
+ for (pid = instance->process_pids;
+ pid && instance->nr_process_pids;
+ pid = pid->next) {
+ if (pid->exclude) {
+ instance->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) {
+ instance->nr_process_pids--;
+ continue;
+ } else if (pidfds[nr_fds] < 0) {
+ ret = 1;
+ goto out;
+ }
+
+ nr_fds++;
+ instance->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
/**
@@ -5866,7 +5943,9 @@ static void parse_record_options(int argc,
fpids_count += add_filter_pid(ctx->instance,
atoi(pid), 0);
pid = strtok_r(NULL, ",", &sav);
+ ctx->instance->nr_process_pids++;
}
+ ctx->instance->process_pids = ctx->instance->filter_pids;
free(pids);
break;
case 'c':
@@ -6361,6 +6440,11 @@ static void record_trace(int argc, char **argv,
}
/* sleep till we are woken with Ctrl^C */
printf("Hit Ctrl^C to stop recording\n");
+ for_all_instances(instance) {
+ if (instance->nr_process_pids
+ && !trace_wait_for_processes(instance))
+ finished = 1;
+ }
while (!finished)
trace_or_sleep(type, pwait);
}
--
2.25.1
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