1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2010 Lennart Poettering
11 #include <linux/oom.h>
16 #include <stdio_ext.h>
20 #include <sys/personality.h>
21 #include <sys/prctl.h>
22 #include <sys/types.h>
26 #if HAVE_VALGRIND_VALGRIND_H
27 #include <valgrind/valgrind.h>
30 #include "alloc-util.h"
31 //#include "architecture.h"
40 #include "process-util.h"
41 #include "raw-clone.h"
42 #include "signal-util.h"
43 //#include "stat-util.h"
44 #include "string-table.h"
45 #include "string-util.h"
46 //#include "terminal-util.h"
47 #include "user-util.h"
50 int get_process_state(pid_t pid) {
54 _cleanup_free_ char *line = NULL;
58 p = procfs_file_alloca(pid, "stat");
60 r = read_one_line_file(p, &line);
66 p = strrchr(line, ')');
72 if (sscanf(p, " %c", &state) != 1)
75 return (unsigned char) state;
78 int get_process_comm(pid_t pid, char **name) {
85 p = procfs_file_alloca(pid, "comm");
87 r = read_one_line_file(p, name);
94 int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) {
95 _cleanup_fclose_ FILE *f = NULL;
104 /* Retrieves a process' command line. Replaces unprintable characters while doing so by whitespace (coalescing
105 * multiple sequential ones into one). If max_length is != 0 will return a string of the specified size at most
106 * (the trailing NUL byte does count towards the length here!), abbreviated with a "..." ellipsis. If
107 * comm_fallback is true and the process has no command line set (the case for kernel threads), or has a
108 * command line that resolves to the empty string will return the "comm" name of the process instead.
110 * Returns -ESRCH if the process doesn't exist, and -ENOENT if the process has no command line (and
111 * comm_fallback is false). Returns 0 and sets *line otherwise. */
113 p = procfs_file_alloca(pid, "cmdline");
122 (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
124 if (max_length == 1) {
126 /* If there's only room for one byte, return the empty string */
134 } else if (max_length == 0) {
135 size_t len = 0, allocated = 0;
137 while ((c = getc(f)) != EOF) {
139 if (!GREEDY_REALLOC(ans, allocated, len+3)) {
161 bool dotdotdot = false;
164 ans = new(char, max_length);
170 while ((c = getc(f)) != EOF) {
197 if (max_length <= 4) {
201 k = ans + max_length - 4;
204 /* Eat up final spaces */
205 while (k > ans && isspace(k[-1])) {
211 strncpy(k, "...", left-1);
217 /* Kernel threads have no argv[] */
219 _cleanup_free_ char *t = NULL;
227 h = get_process_comm(pid, &t);
232 ans = strjoin("[", t, "]");
238 if (l + 3 <= max_length)
239 ans = strjoin("[", t, "]");
240 else if (max_length <= 6) {
242 ans = new(char, max_length);
246 memcpy(ans, "[...]", max_length-1);
247 ans[max_length-1] = 0;
251 t[max_length - 6] = 0;
253 /* Chop off final spaces */
255 while (e > t && isspace(e[-1]))
259 ans = strjoin("[", t, "...]");
270 int rename_process(const char name[]) {
271 static size_t mm_size = 0;
272 static char *mm = NULL;
273 bool truncated = false;
276 /* This is a like a poor man's setproctitle(). It changes the comm field, argv[0], and also the glibc's
277 * internally used name of the process. For the first one a limit of 16 chars applies; to the second one in
278 * many cases one of 10 (i.e. length of "/sbin/init") — however if we have CAP_SYS_RESOURCES it is unbounded;
279 * to the third one 7 (i.e. the length of "systemd". If you pass a longer string it will likely be
282 * Returns 0 if a name was set but truncated, > 0 if it was set but not truncated. */
285 return -EINVAL; /* let's not confuse users unnecessarily with an empty name */
287 if (!is_main_thread())
288 return -EPERM; /* Let's not allow setting the process name from other threads than the main one, as we
289 * cache things without locking, and we make assumptions that PR_SET_NAME sets the
290 * process name that isn't correct on any other threads */
294 /* First step, change the comm field. The main thread's comm is identical to the process comm. This means we
295 * can use PR_SET_NAME, which sets the thread name for the calling thread. */
296 if (prctl(PR_SET_NAME, name) < 0)
297 log_debug_errno(errno, "PR_SET_NAME failed: %m");
298 if (l > 15) /* Linux process names can be 15 chars at max */
301 /* Second step, change glibc's ID of the process name. */
302 if (program_invocation_name) {
305 k = strlen(program_invocation_name);
306 strncpy(program_invocation_name, name, k);
311 /* Third step, completely replace the argv[] array the kernel maintains for us. This requires privileges, but
312 * has the advantage that the argv[] array is exactly what we want it to be, and not filled up with zeros at
313 * the end. This is the best option for changing /proc/self/cmdline. */
315 /* Let's not bother with this if we don't have euid == 0. Strictly speaking we should check for the
316 * CAP_SYS_RESOURCE capability which is independent of the euid. In our own code the capability generally is
317 * present only for euid == 0, hence let's use this as quick bypass check, to avoid calling mmap() if
318 * PR_SET_MM_ARG_{START,END} fails with EPERM later on anyway. After all geteuid() is dead cheap to call, but
321 log_debug("Skipping PR_SET_MM, as we don't have privileges.");
322 else if (mm_size < l+1) {
326 nn_size = PAGE_ALIGN(l+1);
327 nn = mmap(NULL, nn_size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
328 if (nn == MAP_FAILED) {
329 log_debug_errno(errno, "mmap() failed: %m");
333 strncpy(nn, name, nn_size);
335 /* Now, let's tell the kernel about this new memory */
336 if (prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long) nn, 0, 0) < 0) {
337 log_debug_errno(errno, "PR_SET_MM_ARG_START failed, proceeding without: %m");
338 (void) munmap(nn, nn_size);
342 /* And update the end pointer to the new end, too. If this fails, we don't really know what to do, it's
343 * pretty unlikely that we can rollback, hence we'll just accept the failure, and continue. */
344 if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0)
345 log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m");
348 (void) munmap(mm, mm_size);
353 strncpy(mm, name, mm_size);
355 /* Update the end pointer, continuing regardless of any failure. */
356 if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) mm + l + 1, 0, 0) < 0)
357 log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m");
361 /* Fourth step: in all cases we'll also update the original argv[], so that our own code gets it right too if
362 * it still looks here */
364 if (saved_argc > 0) {
370 k = strlen(saved_argv[0]);
371 strncpy(saved_argv[0], name, k);
376 for (i = 1; i < saved_argc; i++) {
380 memzero(saved_argv[i], strlen(saved_argv[i]));
387 int is_kernel_thread(pid_t pid) {
388 _cleanup_free_ char *line = NULL;
389 unsigned long long flags;
395 if (IN_SET(pid, 0, 1) || pid == getpid_cached()) /* pid 1, and we ourselves certainly aren't a kernel thread */
397 if (!pid_is_valid(pid))
400 p = procfs_file_alloca(pid, "stat");
401 r = read_one_line_file(p, &line);
407 /* Skip past the comm field */
408 q = strrchr(line, ')');
413 /* Skip 6 fields to reach the flags field */
414 for (i = 0; i < 6; i++) {
415 l = strspn(q, WHITESPACE);
420 l = strcspn(q, WHITESPACE);
426 /* Skip preceeding whitespace */
427 l = strspn(q, WHITESPACE);
432 /* Truncate the rest */
433 l = strcspn(q, WHITESPACE);
438 r = safe_atollu(q, &flags);
442 return !!(flags & PF_KTHREAD);
445 #if 0 /// UNNEEDED by elogind
446 int get_process_capeff(pid_t pid, char **capeff) {
453 p = procfs_file_alloca(pid, "status");
455 r = get_proc_field(p, "CapEff", WHITESPACE, capeff);
463 static int get_process_link_contents(const char *proc_file, char **name) {
469 r = readlink_malloc(proc_file, name);
478 int get_process_exe(pid_t pid, char **name) {
485 p = procfs_file_alloca(pid, "exe");
486 r = get_process_link_contents(p, name);
490 d = endswith(*name, " (deleted)");
497 #if 0 /// UNNEEDED by elogind
498 static int get_process_id(pid_t pid, const char *field, uid_t *uid) {
499 _cleanup_fclose_ FILE *f = NULL;
509 p = procfs_file_alloca(pid, "status");
517 (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
519 FOREACH_LINE(line, f, return -errno) {
524 if (startswith(l, field)) {
526 l += strspn(l, WHITESPACE);
528 l[strcspn(l, WHITESPACE)] = 0;
530 return parse_uid(l, uid);
537 int get_process_uid(pid_t pid, uid_t *uid) {
539 if (pid == 0 || pid == getpid_cached()) {
544 return get_process_id(pid, "Uid:", uid);
547 int get_process_gid(pid_t pid, gid_t *gid) {
549 if (pid == 0 || pid == getpid_cached()) {
554 assert_cc(sizeof(uid_t) == sizeof(gid_t));
555 return get_process_id(pid, "Gid:", gid);
558 int get_process_cwd(pid_t pid, char **cwd) {
563 p = procfs_file_alloca(pid, "cwd");
565 return get_process_link_contents(p, cwd);
568 int get_process_root(pid_t pid, char **root) {
573 p = procfs_file_alloca(pid, "root");
575 return get_process_link_contents(p, root);
578 int get_process_environ(pid_t pid, char **env) {
579 _cleanup_fclose_ FILE *f = NULL;
580 _cleanup_free_ char *outcome = NULL;
583 size_t allocated = 0, sz = 0;
588 p = procfs_file_alloca(pid, "environ");
597 (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
599 while ((c = fgetc(f)) != EOF) {
600 if (!GREEDY_REALLOC(outcome, allocated, sz + 5))
604 outcome[sz++] = '\n';
606 sz += cescape_char(c, outcome + sz);
610 outcome = strdup("");
616 *env = TAKE_PTR(outcome);
621 int get_process_ppid(pid_t pid, pid_t *_ppid) {
623 _cleanup_free_ char *line = NULL;
630 if (pid == 0 || pid == getpid_cached()) {
635 p = procfs_file_alloca(pid, "stat");
636 r = read_one_line_file(p, &line);
642 /* Let's skip the pid and comm fields. The latter is enclosed
643 * in () but does not escape any () in its value, so let's
644 * skip over it manually */
646 p = strrchr(line, ')');
658 if ((long unsigned) (pid_t) ppid != ppid)
661 *_ppid = (pid_t) ppid;
667 int wait_for_terminate(pid_t pid, siginfo_t *status) {
678 if (waitid(P_PID, pid, status, WEXITED) < 0) {
683 return negative_errno();
692 * < 0 : wait_for_terminate() failed to get the state of the
693 * process, the process was terminated by a signal, or
694 * failed for an unknown reason.
695 * >=0 : The process terminated normally, and its exit code is
698 * That is, success is indicated by a return value of zero, and an
699 * error is indicated by a non-zero value.
701 * A warning is emitted if the process terminates abnormally,
702 * and also if it returns non-zero unless check_exit_code is true.
704 int wait_for_terminate_and_check(const char *name, pid_t pid, WaitFlags flags) {
705 _cleanup_free_ char *buffer = NULL;
712 r = get_process_comm(pid, &buffer);
714 log_debug_errno(r, "Failed to acquire process name of " PID_FMT ", ignoring: %m", pid);
719 prio = flags & WAIT_LOG_ABNORMAL ? LOG_ERR : LOG_DEBUG;
721 r = wait_for_terminate(pid, &status);
723 return log_full_errno(prio, r, "Failed to wait for %s: %m", strna(name));
725 if (status.si_code == CLD_EXITED) {
726 if (status.si_status != EXIT_SUCCESS)
727 log_full(flags & WAIT_LOG_NON_ZERO_EXIT_STATUS ? LOG_ERR : LOG_DEBUG,
728 "%s failed with exit status %i.", strna(name), status.si_status);
730 log_debug("%s succeeded.", name);
732 return status.si_status;
734 } else if (IN_SET(status.si_code, CLD_KILLED, CLD_DUMPED)) {
736 log_full(prio, "%s terminated by signal %s.", strna(name), signal_to_string(status.si_status));
740 log_full(prio, "%s failed due to unknown reason.", strna(name));
746 * < 0 : wait_for_terminate_with_timeout() failed to get the state of the
747 * process, the process timed out, the process was terminated by a
748 * signal, or failed for an unknown reason.
749 * >=0 : The process terminated normally with no failures.
751 * Success is indicated by a return value of zero, a timeout is indicated
752 * by ETIMEDOUT, and all other child failure states are indicated by error
753 * is indicated by a non-zero value.
755 int wait_for_terminate_with_timeout(pid_t pid, usec_t timeout) {
760 assert_se(sigemptyset(&mask) == 0);
761 assert_se(sigaddset(&mask, SIGCHLD) == 0);
763 /* Drop into a sigtimewait-based timeout. Waiting for the
765 until = now(CLOCK_MONOTONIC) + timeout;
768 siginfo_t status = {};
771 n = now(CLOCK_MONOTONIC);
775 r = sigtimedwait(&mask, NULL, timespec_store(&ts, until - n)) < 0 ? -errno : 0;
776 /* Assuming we woke due to the child exiting. */
777 if (waitid(P_PID, pid, &status, WEXITED|WNOHANG) == 0) {
778 if (status.si_pid == pid) {
779 /* This is the correct child.*/
780 if (status.si_code == CLD_EXITED)
781 return (status.si_status == 0) ? 0 : -EPROTO;
786 /* Not the child, check for errors and proceed appropriately */
790 /* Timed out, child is likely hung. */
793 /* Received a different signal and should retry */
796 /* Return any unexpected errors */
805 #if 0 /// UNNEEDED by elogind
806 void sigkill_wait(pid_t pid) {
809 if (kill(pid, SIGKILL) > 0)
810 (void) wait_for_terminate(pid, NULL);
813 void sigkill_waitp(pid_t *pid) {
825 void sigterm_wait(pid_t pid) {
828 if (kill_and_sigcont(pid, SIGTERM) > 0)
829 (void) wait_for_terminate(pid, NULL);
832 int kill_and_sigcont(pid_t pid, int sig) {
835 r = kill(pid, sig) < 0 ? -errno : 0;
837 /* If this worked, also send SIGCONT, unless we already just sent a SIGCONT, or SIGKILL was sent which isn't
838 * affected by a process being suspended anyway. */
839 if (r >= 0 && !IN_SET(sig, SIGCONT, SIGKILL))
840 (void) kill(pid, SIGCONT);
845 int getenv_for_pid(pid_t pid, const char *field, char **ret) {
846 _cleanup_fclose_ FILE *f = NULL;
856 if (pid == 0 || pid == getpid_cached()) {
873 path = procfs_file_alloca(pid, "environ");
875 f = fopen(path, "re");
883 (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
891 for (i = 0; i < sizeof(line)-1; i++) {
895 if (_unlikely_(c == EOF)) {
905 if (strneq(line, field, l) && line[l] == '=') {
906 value = strdup(line + l + 1);
920 bool pid_is_unwaited(pid_t pid) {
921 /* Checks whether a PID is still valid at all, including a zombie */
926 if (pid <= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
929 if (pid == getpid_cached())
932 if (kill(pid, 0) >= 0)
935 return errno != ESRCH;
938 bool pid_is_alive(pid_t pid) {
941 /* Checks whether a PID is still valid and not a zombie */
946 if (pid <= 1) /* If we or PID 1 would be a zombie, this code would not be running */
949 if (pid == getpid_cached())
952 r = get_process_state(pid);
953 if (IN_SET(r, -ESRCH, 'Z'))
959 #if 0 /// UNNEEDED by elogind
960 int pid_from_same_root_fs(pid_t pid) {
966 if (pid == 0 || pid == getpid_cached())
969 root = procfs_file_alloca(pid, "root");
971 return files_same(root, "/proc/1/root", 0);
975 bool is_main_thread(void) {
976 static thread_local int cached = 0;
978 if (_unlikely_(cached == 0))
979 cached = getpid_cached() == gettid() ? 1 : -1;
984 #if 0 /// UNNEEDED by elogind
985 _noreturn_ void freeze(void) {
989 /* Make sure nobody waits for us on a socket anymore */
990 close_all_fds(NULL, 0);
994 /* Let's not freeze right away, but keep reaping zombies. */
999 r = waitid(P_ALL, 0, &si, WEXITED);
1000 if (r < 0 && errno != EINTR)
1004 /* waitid() failed with an unexpected error, things are really borked. Freeze now! */
1009 bool oom_score_adjust_is_valid(int oa) {
1010 return oa >= OOM_SCORE_ADJ_MIN && oa <= OOM_SCORE_ADJ_MAX;
1013 unsigned long personality_from_string(const char *p) {
1017 return PERSONALITY_INVALID;
1019 /* Parse a personality specifier. We use our own identifiers that indicate specific ABIs, rather than just
1020 * hints regarding the register size, since we want to keep things open for multiple locally supported ABIs for
1021 * the same register size. */
1023 architecture = architecture_from_string(p);
1024 if (architecture < 0)
1025 return PERSONALITY_INVALID;
1027 if (architecture == native_architecture())
1029 #ifdef SECONDARY_ARCHITECTURE
1030 if (architecture == SECONDARY_ARCHITECTURE)
1034 return PERSONALITY_INVALID;
1037 const char* personality_to_string(unsigned long p) {
1038 int architecture = _ARCHITECTURE_INVALID;
1041 architecture = native_architecture();
1042 #ifdef SECONDARY_ARCHITECTURE
1043 else if (p == PER_LINUX32)
1044 architecture = SECONDARY_ARCHITECTURE;
1047 if (architecture < 0)
1050 return architecture_to_string(architecture);
1053 int safe_personality(unsigned long p) {
1056 /* So here's the deal, personality() is weirdly defined by glibc. In some cases it returns a failure via errno,
1057 * and in others as negative return value containing an errno-like value. Let's work around this: this is a
1058 * wrapper that uses errno if it is set, and uses the return value otherwise. And then it sets both errno and
1059 * the return value indicating the same issue, so that we are definitely on the safe side.
1061 * See https://github.com/systemd/systemd/issues/6737 */
1064 ret = personality(p);
1075 int opinionated_personality(unsigned long *ret) {
1078 /* Returns the current personality, or PERSONALITY_INVALID if we can't determine it. This function is a bit
1079 * opinionated though, and ignores all the finer-grained bits and exotic personalities, only distinguishing the
1080 * two most relevant personalities: PER_LINUX and PER_LINUX32. */
1082 current = safe_personality(PERSONALITY_INVALID);
1086 if (((unsigned long) current & 0xffff) == PER_LINUX32)
1094 void valgrind_summary_hack(void) {
1095 #if HAVE_VALGRIND_VALGRIND_H
1096 if (getpid_cached() == 1 && RUNNING_ON_VALGRIND) {
1098 pid = raw_clone(SIGCHLD);
1100 log_emergency_errno(errno, "Failed to fork off valgrind helper: %m");
1104 log_info("Spawned valgrind helper as PID "PID_FMT".", pid);
1105 (void) wait_for_terminate(pid, NULL);
1111 int pid_compare_func(const void *a, const void *b) {
1112 const pid_t *p = a, *q = b;
1114 /* Suitable for usage in qsort() */
1123 int ioprio_parse_priority(const char *s, int *ret) {
1129 r = safe_atoi(s, &i);
1133 if (!ioprio_priority_is_valid(i))
1141 /* The cached PID, possible values:
1143 * == UNSET [0] → cache not initialized yet
1144 * == BUSY [-1] → some thread is initializing it at the moment
1145 * any other → the cached PID
1148 #define CACHED_PID_UNSET ((pid_t) 0)
1149 #define CACHED_PID_BUSY ((pid_t) -1)
1151 static pid_t cached_pid = CACHED_PID_UNSET;
1153 void reset_cached_pid(void) {
1154 /* Invoked in the child after a fork(), i.e. at the first moment the PID changed */
1155 cached_pid = CACHED_PID_UNSET;
1158 /* We use glibc __register_atfork() + __dso_handle directly here, as they are not included in the glibc
1159 * headers. __register_atfork() is mostly equivalent to pthread_atfork(), but doesn't require us to link against
1160 * libpthread, as it is part of glibc anyway. */
1162 extern int __register_atfork(void (*prepare) (void), void (*parent) (void), void (*child) (void), void * __dso_handle);
1163 extern void* __dso_handle __attribute__ ((__weak__));
1164 #endif // ifdef __GLIBC__
1166 pid_t getpid_cached(void) {
1167 static bool installed = false;
1168 pid_t current_value;
1170 /* getpid_cached() is much like getpid(), but caches the value in local memory, to avoid having to invoke a
1171 * system call each time. This restores glibc behaviour from before 2.24, when getpid() was unconditionally
1172 * cached. Starting with 2.24 getpid() started to become prohibitively expensive when used for detecting when
1173 * objects were used across fork()s. With this caching the old behaviour is somewhat restored.
1175 * https://bugzilla.redhat.com/show_bug.cgi?id=1443976
1176 * https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c579f48edba88380635ab98cb612030e3ed8691e
1179 current_value = __sync_val_compare_and_swap(&cached_pid, CACHED_PID_UNSET, CACHED_PID_BUSY);
1181 switch (current_value) {
1183 case CACHED_PID_UNSET: { /* Not initialized yet, then do so now */
1186 new_pid = raw_getpid();
1189 /* __register_atfork() either returns 0 or -ENOMEM, in its glibc implementation. Since it's
1190 * only half-documented (glibc doesn't document it but LSB does — though only superficially)
1191 * we'll check for errors only in the most generic fashion possible. */
1193 if (__register_atfork(NULL, NULL, reset_cached_pid, __dso_handle) != 0) {
1194 /* OOM? Let's try again later */
1195 cached_pid = CACHED_PID_UNSET;
1202 cached_pid = new_pid;
1206 case CACHED_PID_BUSY: /* Somebody else is currently initializing */
1207 return raw_getpid();
1209 default: /* Properly initialized */
1210 return current_value;
1214 int must_be_root(void) {
1219 log_error("Need to be root.");
1225 const int except_fds[],
1226 size_t n_except_fds,
1230 pid_t original_pid, pid;
1231 sigset_t saved_ss, ss;
1232 bool block_signals = false;
1235 /* A wrapper around fork(), that does a couple of important initializations in addition to mere forking. Always
1236 * returns the child's PID in *ret_pid. Returns == 0 in the child, and > 0 in the parent. */
1238 prio = flags & FORK_LOG ? LOG_ERR : LOG_DEBUG;
1240 original_pid = getpid_cached();
1242 if (flags & (FORK_RESET_SIGNALS|FORK_DEATHSIG)) {
1244 /* We temporarily block all signals, so that the new child has them blocked initially. This way, we can
1245 * be sure that SIGTERMs are not lost we might send to the child. */
1247 if (sigfillset(&ss) < 0)
1248 return log_full_errno(prio, errno, "Failed to reset signal set: %m");
1250 block_signals = true;
1252 } else if (flags & FORK_WAIT) {
1254 /* Let's block SIGCHLD at least, so that we can safely watch for the child process */
1256 if (sigemptyset(&ss) < 0)
1257 return log_full_errno(prio, errno, "Failed to clear signal set: %m");
1259 if (sigaddset(&ss, SIGCHLD) < 0)
1260 return log_full_errno(prio, errno, "Failed to add SIGCHLD to signal set: %m");
1262 block_signals = true;
1266 if (sigprocmask(SIG_SETMASK, &ss, &saved_ss) < 0)
1267 return log_full_errno(prio, errno, "Failed to set signal mask: %m");
1269 if (flags & FORK_NEW_MOUNTNS)
1270 pid = raw_clone(SIGCHLD|CLONE_NEWNS);
1276 if (block_signals) /* undo what we did above */
1277 (void) sigprocmask(SIG_SETMASK, &saved_ss, NULL);
1279 return log_full_errno(prio, r, "Failed to fork: %m");
1282 /* We are in the parent process */
1284 log_debug("Successfully forked off '%s' as PID " PID_FMT ".", strna(name), pid);
1286 if (flags & FORK_WAIT) {
1287 r = wait_for_terminate_and_check(name, pid, (flags & FORK_LOG ? WAIT_LOG : 0));
1290 if (r != EXIT_SUCCESS) /* exit status > 0 should be treated as failure, too */
1294 if (block_signals) /* undo what we did above */
1295 (void) sigprocmask(SIG_SETMASK, &saved_ss, NULL);
1303 /* We are in the child process */
1305 if (flags & FORK_REOPEN_LOG) {
1306 /* Close the logs if requested, before we log anything. And make sure we reopen it if needed. */
1308 log_set_open_when_needed(true);
1312 r = rename_process(name);
1314 log_full_errno(flags & FORK_LOG ? LOG_WARNING : LOG_DEBUG,
1315 r, "Failed to rename process, ignoring: %m");
1318 if (flags & FORK_DEATHSIG)
1319 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) {
1320 log_full_errno(prio, errno, "Failed to set death signal: %m");
1321 _exit(EXIT_FAILURE);
1324 if (flags & FORK_RESET_SIGNALS) {
1325 r = reset_all_signal_handlers();
1327 log_full_errno(prio, r, "Failed to reset signal handlers: %m");
1328 _exit(EXIT_FAILURE);
1331 /* This implicitly undoes the signal mask stuff we did before the fork()ing above */
1332 r = reset_signal_mask();
1334 log_full_errno(prio, r, "Failed to reset signal mask: %m");
1335 _exit(EXIT_FAILURE);
1337 } else if (block_signals) { /* undo what we did above */
1338 if (sigprocmask(SIG_SETMASK, &saved_ss, NULL) < 0) {
1339 log_full_errno(prio, errno, "Failed to restore signal mask: %m");
1340 _exit(EXIT_FAILURE);
1344 if (flags & FORK_DEATHSIG) {
1346 /* Let's see if the parent PID is still the one we started from? If not, then the parent
1347 * already died by the time we set PR_SET_PDEATHSIG, hence let's emulate the effect */
1351 /* Parent is in a differn't PID namespace. */;
1352 else if (ppid != original_pid) {
1353 log_debug("Parent died early, raising SIGTERM.");
1354 (void) raise(SIGTERM);
1355 _exit(EXIT_FAILURE);
1359 if (flags & FORK_CLOSE_ALL_FDS) {
1360 /* Close the logs here in case it got reopened above, as close_all_fds() would close them for us */
1363 r = close_all_fds(except_fds, n_except_fds);
1365 log_full_errno(prio, r, "Failed to close all file descriptors: %m");
1366 _exit(EXIT_FAILURE);
1370 /* When we were asked to reopen the logs, do so again now */
1371 if (flags & FORK_REOPEN_LOG) {
1373 log_set_open_when_needed(false);
1376 if (flags & FORK_NULL_STDIO) {
1377 r = make_null_stdio();
1379 log_full_errno(prio, r, "Failed to connect stdin/stdout to /dev/null: %m");
1380 _exit(EXIT_FAILURE);
1385 *ret_pid = getpid_cached();
1390 int fork_agent(const char *name, const int except[], unsigned n_except, pid_t *ret_pid, const char *path, ...) {
1391 bool stdout_is_tty, stderr_is_tty;
1399 /* Spawns a temporary TTY agent, making sure it goes away when we go away */
1401 r = safe_fork_full(name, except, n_except, FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_CLOSE_ALL_FDS, ret_pid);
1409 stdout_is_tty = isatty(STDOUT_FILENO);
1410 stderr_is_tty = isatty(STDERR_FILENO);
1412 if (!stdout_is_tty || !stderr_is_tty) {
1415 /* Detach from stdout/stderr. and reopen
1416 * /dev/tty for them. This is important to
1417 * ensure that when systemctl is started via
1418 * popen() or a similar call that expects to
1419 * read EOF we actually do generate EOF and
1420 * not delay this indefinitely by because we
1421 * keep an unused copy of stdin around. */
1422 fd = open("/dev/tty", O_WRONLY);
1424 log_error_errno(errno, "Failed to open /dev/tty: %m");
1425 _exit(EXIT_FAILURE);
1428 if (!stdout_is_tty && dup2(fd, STDOUT_FILENO) < 0) {
1429 log_error_errno(errno, "Failed to dup2 /dev/tty: %m");
1430 _exit(EXIT_FAILURE);
1433 if (!stderr_is_tty && dup2(fd, STDERR_FILENO) < 0) {
1434 log_error_errno(errno, "Failed to dup2 /dev/tty: %m");
1435 _exit(EXIT_FAILURE);
1438 safe_close_above_stdio(fd);
1441 /* Count arguments */
1443 for (n = 0; va_arg(ap, char*); n++)
1448 l = alloca(sizeof(char *) * (n + 1));
1450 /* Fill in arguments */
1452 for (i = 0; i <= n; i++)
1453 l[i] = va_arg(ap, char*);
1457 _exit(EXIT_FAILURE);
1460 #if 0 /// UNNEEDED by elogind
1461 static const char *const ioprio_class_table[] = {
1462 [IOPRIO_CLASS_NONE] = "none",
1463 [IOPRIO_CLASS_RT] = "realtime",
1464 [IOPRIO_CLASS_BE] = "best-effort",
1465 [IOPRIO_CLASS_IDLE] = "idle"
1468 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ioprio_class, int, IOPRIO_N_CLASSES);
1470 static const char *const sigchld_code_table[] = {
1471 [CLD_EXITED] = "exited",
1472 [CLD_KILLED] = "killed",
1473 [CLD_DUMPED] = "dumped",
1474 [CLD_TRAPPED] = "trapped",
1475 [CLD_STOPPED] = "stopped",
1476 [CLD_CONTINUED] = "continued",
1479 DEFINE_STRING_TABLE_LOOKUP(sigchld_code, int);
1481 static const char* const sched_policy_table[] = {
1482 [SCHED_OTHER] = "other",
1483 [SCHED_BATCH] = "batch",
1484 [SCHED_IDLE] = "idle",
1485 [SCHED_FIFO] = "fifo",
1489 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(sched_policy, int, INT_MAX);