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author | Lennart Poettering <lennart@poettering.net> | 2017-12-22 13:08:14 +0100 |
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committer | Lennart Poettering <lennart@poettering.net> | 2017-12-25 11:48:21 +0100 |
commit | 4c253ed1cae8b4df72ce1353ee826a4fae399e25 (patch) | |
tree | 5fc52b199a402b4ddaae0e3005fa85cc610c377f /src/activate/activate.c | |
parent | d8caff6db672ab0f2d8064c61f5ef0e8e8d288ca (diff) | |
download | systemd-4c253ed1cae8b4df72ce1353ee826a4fae399e25.tar.gz |
tree-wide: introduce new safe_fork() helper and port everything over
This adds a new safe_fork() wrapper around fork() and makes use of it
everywhere. The new wrapper does a couple of things we previously did
manually and separately in a safer, more correct and automatic way:
1. Optionally resets signal handlers/mask in the child
2. Sets a name on all processes we fork off right after forking off (and
the patch assigns useful names for all processes we fork off now,
following a systematic naming scheme: always enclosed in () – in order
to indicate that these are not proper, exec()ed processes, but only
forked off children, and if the process is long-running with only our
own code, without execve()'ing something else, it gets am "sd-" prefix.)
3. Optionally closes all file descriptors in the child
4. Optionally sets a PR_SET_DEATHSIG to SIGTERM in the child, in a safe
way so that the parent dying before this happens being handled
safely.
5. Optionally reopens the logs
6. Optionally connects stdin/stdout/stderr to /dev/null
7. Debug logs about the forked off processes.
Diffstat (limited to 'src/activate/activate.c')
-rw-r--r-- | src/activate/activate.c | 31 |
1 files changed, 8 insertions, 23 deletions
diff --git a/src/activate/activate.c b/src/activate/activate.c index 83807efdcf..67067a8f32 100644 --- a/src/activate/activate.c +++ b/src/activate/activate.c @@ -267,38 +267,23 @@ static int exec_process(const char* name, char **argv, char **env, int start_fd, static int fork_and_exec_process(const char* child, char** argv, char **env, int fd) { _cleanup_free_ char *joined = NULL; - pid_t parent_pid, child_pid; + pid_t child_pid; + int r; joined = strv_join(argv, " "); if (!joined) return log_oom(); - parent_pid = getpid_cached(); - - child_pid = fork(); - if (child_pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - - /* In the child */ - if (child_pid == 0) { - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - /* Make sure the child goes away when the parent dies */ - if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) - _exit(EXIT_FAILURE); - - /* Check whether our parent died before we were able - * to set the death signal */ - if (getppid() != parent_pid) - _exit(EXIT_SUCCESS); - + r = safe_fork("(activate)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child_pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { + /* In the child */ exec_process(child, argv, env, fd, 1); _exit(EXIT_FAILURE); } - log_info("Spawned %s (%s) as PID %d", child, joined, child_pid); + log_info("Spawned %s (%s) as PID " PID_FMT ".", child, joined, child_pid); return 0; } |