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author | Lennart Poettering <lennart@poettering.net> | 2017-12-22 13:08:14 +0100 |
---|---|---|
committer | Lennart Poettering <lennart@poettering.net> | 2017-12-25 11:48:21 +0100 |
commit | 4c253ed1cae8b4df72ce1353ee826a4fae399e25 (patch) | |
tree | 5fc52b199a402b4ddaae0e3005fa85cc610c377f | |
parent | terminal-util: open /dev/null with O_CLOEXEC in make_stdio_null() (diff) | |
download | systemd-4c253ed1cae8b4df72ce1353ee826a4fae399e25.tar.xz systemd-4c253ed1cae8b4df72ce1353ee826a4fae399e25.zip |
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.
42 files changed, 448 insertions, 507 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; } diff --git a/src/basic/async.c b/src/basic/async.c index c510cbd7f5..21e05d9c2c 100644 --- a/src/basic/async.c +++ b/src/basic/async.c @@ -61,29 +61,18 @@ finish: } int asynchronous_sync(void) { - pid_t pid; + int r; /* This forks off an invocation of fork() as a child process, in order to initiate synchronization to * disk. Note that we implement this as helper process rather than thread as we don't want the sync() to hang our * original process ever, and a thread would do that as the process can't exit with threads hanging in blocking * syscalls. */ - log_debug("Spawning new process for sync"); - - pid = fork(); - if (pid < 0) - return -errno; - - if (pid == 0) { + r = safe_fork("(sd-sync)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, NULL); + if (r < 0) + return r; + if (r == 0) { /* Child process */ - - (void) rename_process("(sd-sync)"); - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - (void) close_all_fds(NULL, 0); - (void) sync(); _exit(EXIT_SUCCESS); } diff --git a/src/basic/calendarspec.c b/src/basic/calendarspec.c index e6add0c383..dbd7fb1d76 100644 --- a/src/basic/calendarspec.c +++ b/src/basic/calendarspec.c @@ -1348,9 +1348,8 @@ typedef struct SpecNextResult { } SpecNextResult; int calendar_spec_next_usec(const CalendarSpec *spec, usec_t usec, usec_t *next) { + SpecNextResult *shared, tmp; pid_t pid; - SpecNextResult *shared; - SpecNextResult tmp; int r; if (isempty(spec->timezone)) @@ -1360,15 +1359,12 @@ int calendar_spec_next_usec(const CalendarSpec *spec, usec_t usec, usec_t *next) if (shared == MAP_FAILED) return negative_errno(); - pid = fork(); - - if (pid == -1) { - int fork_errno = errno; + r = safe_fork("(sd-calendar)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG, &pid); + if (r < 0) { (void) munmap(shared, sizeof *shared); - return -fork_errno; + return r; } - - if (pid == 0) { + if (r == 0) { if (setenv("TZ", spec->timezone, 1) != 0) { shared->return_value = negative_errno(); _exit(EXIT_FAILURE); diff --git a/src/basic/exec-util.c b/src/basic/exec-util.c index 82ccbdf5ec..afad636db5 100644 --- a/src/basic/exec-util.c +++ b/src/basic/exec-util.c @@ -48,20 +48,19 @@ assert_cc(EAGAIN == EWOULDBLOCK); static int do_spawn(const char *path, char *argv[], int stdout_fd, pid_t *pid) { pid_t _pid; + int r; if (null_or_empty_path(path)) { log_debug("%s is empty (a mask).", path); return 0; } - _pid = fork(); - if (_pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - if (_pid == 0) { + r = safe_fork("(direxec)", FORK_DEATHSIG, &_pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { char *_argv[2]; - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - if (stdout_fd >= 0) { /* If the fd happens to be in the right place, go along with that */ if (stdout_fd != STDOUT_FILENO && @@ -107,11 +106,6 @@ static int do_execute( * If callbacks is nonnull, execution is serial. Otherwise, we default to parallel. */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - r = conf_files_list_strv(&paths, NULL, NULL, CONF_FILES_EXECUTABLE, (const char* const*) directories); if (r < 0) return r; @@ -222,11 +216,10 @@ int execute_directories( * them to finish. Optionally a timeout is applied. If a file with the same name * exists in more than one directory, the earliest one wins. */ - executor_pid = fork(); - if (executor_pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - - if (executor_pid == 0) { + r = safe_fork("(sd-executor)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &executor_pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { r = do_execute(dirs, timeout, callbacks, callback_args, fd, argv); _exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS); } diff --git a/src/basic/process-util.c b/src/basic/process-util.c index 17c94f44a0..01c73cfa64 100644 --- a/src/basic/process-util.c +++ b/src/basic/process-util.c @@ -56,6 +56,7 @@ #include "stat-util.h" #include "string-table.h" #include "string-util.h" +#include "terminal-util.h" #include "user-util.h" #include "util.h" @@ -1134,6 +1135,142 @@ int must_be_root(void) { return -EPERM; } +int safe_fork_full( + const char *name, + const int except_fds[], + size_t n_except_fds, + ForkFlags flags, + pid_t *ret_pid) { + + pid_t original_pid, pid; + sigset_t saved_ss; + bool block_signals; + int r; + + /* A wrapper around fork(), that does a couple of important initializations in addition to mere forking. Always + * returns the child's PID in *ret_pid. Returns == 0 in the child, and > 0 in the parent. */ + + original_pid = getpid_cached(); + + block_signals = flags & (FORK_RESET_SIGNALS|FORK_DEATHSIG); + + if (block_signals) { + sigset_t ss; + + /* We temporarily block all signals, so that the new child has them blocked initially. This way, we can be sure + * that SIGTERMs are not lost we might send to the child. */ + if (sigfillset(&ss) < 0) + return log_debug_errno(errno, "Failed to reset signal set: %m"); + + if (sigprocmask(SIG_SETMASK, &ss, &saved_ss) < 0) + return log_debug_errno(errno, "Failed to reset signal mask: %m"); + } + + pid = fork(); + if (pid < 0) { + r = -errno; + + if (block_signals) /* undo what we did above */ + (void) sigprocmask(SIG_SETMASK, &saved_ss, NULL); + + return log_debug_errno(r, "Failed to fork: %m"); + } + if (pid > 0) { + /* We are in the parent process */ + + if (block_signals) /* undo what we did above */ + (void) sigprocmask(SIG_SETMASK, &saved_ss, NULL); + + log_debug("Sucessfully forked off '%s' as PID " PID_FMT ".", strna(name), pid); + + if (ret_pid) + *ret_pid = pid; + + return 1; + } + + /* We are in the child process */ + + if (flags & FORK_REOPEN_LOG) { + /* Close the logs if requested, before we log anything. And make sure we reopen it if needed. */ + log_close(); + log_set_open_when_needed(true); + } + + if (name) { + r = rename_process(name); + if (r < 0) + log_debug_errno(r, "Failed to rename process, ignoring: %m"); + } + + if (flags & FORK_DEATHSIG) + if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) { + log_debug_errno(errno, "Failed to set death signal: %m"); + _exit(EXIT_FAILURE); + } + + if (flags & FORK_RESET_SIGNALS) { + r = reset_all_signal_handlers(); + if (r < 0) { + log_debug_errno(r, "Failed to reset signal handlers: %m"); + _exit(EXIT_FAILURE); + } + + /* This implicitly undoes the signal mask stuff we did before the fork()ing above */ + r = reset_signal_mask(); + if (r < 0) { + log_debug_errno(r, "Failed to reset signal mask: %m"); + _exit(EXIT_FAILURE); + } + } else if (block_signals) { /* undo what we did above */ + if (sigprocmask(SIG_SETMASK, &saved_ss, NULL) < 0) { + log_debug_errno(errno, "Failed to restore signal mask: %m"); + _exit(EXIT_FAILURE); + } + } + + if (flags & FORK_DEATHSIG) { + /* Let's see if the parent PID is still the one we started from? If not, then the parent + * already died by the time we set PR_SET_PDEATHSIG, hence let's emulate the effect */ + + if (getppid() != original_pid) { + log_debug("Parent died early, raising SIGTERM."); + (void) raise(SIGTERM); + _exit(EXIT_FAILURE); + } + } + + if (flags & FORK_CLOSE_ALL_FDS) { + /* Close the logs here in case it got reopened above, as close_all_fds() would close them for us */ + log_close(); + + r = close_all_fds(except_fds, n_except_fds); + if (r < 0) { + log_debug_errno(r, "Failed to close all file descriptors: %m"); + _exit(EXIT_FAILURE); + } + } + + /* When we were asked to reopen the logs, do so again now */ + if (flags & FORK_REOPEN_LOG) { + log_open(); + log_set_open_when_needed(false); + } + + if (flags & FORK_NULL_STDIO) { + r = make_null_stdio(); + if (r < 0) { + log_debug_errno(r, "Failed to connect stdin/stdout to /dev/null: %m"); + _exit(EXIT_FAILURE); + } + } + + if (ret_pid) + *ret_pid = getpid_cached(); + + return 0; +} + static const char *const ioprio_class_table[] = { [IOPRIO_CLASS_NONE] = "none", [IOPRIO_CLASS_RT] = "realtime", diff --git a/src/basic/process-util.h b/src/basic/process-util.h index 1b7e692060..0ab1eecd90 100644 --- a/src/basic/process-util.h +++ b/src/basic/process-util.h @@ -142,3 +142,17 @@ int ioprio_parse_priority(const char *s, int *ret); pid_t getpid_cached(void); int must_be_root(void); + +typedef enum ForkFlags { + FORK_RESET_SIGNALS = 1U << 0, + FORK_CLOSE_ALL_FDS = 1U << 1, + FORK_DEATHSIG = 1U << 2, + FORK_NULL_STDIO = 1U << 3, + FORK_REOPEN_LOG = 1U << 4, +} ForkFlags; + +int safe_fork_full(const char *name, const int except_fds[], size_t n_except_fds, ForkFlags flags, pid_t *ret_pid); + +static inline int safe_fork(const char *name, ForkFlags flags, pid_t *ret_pid) { + return safe_fork_full(name, NULL, 0, flags, ret_pid); +} diff --git a/src/basic/terminal-util.c b/src/basic/terminal-util.c index 6051daf5bb..d15fa38207 100644 --- a/src/basic/terminal-util.c +++ b/src/basic/terminal-util.c @@ -1106,11 +1106,10 @@ int openpt_in_namespace(pid_t pid, int flags) { if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return -errno; - - if (child == 0) { + r = safe_fork("(sd-openpt)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return r; + if (r == 0) { int master; pair[0] = safe_close(pair[0]); @@ -1157,11 +1156,10 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode) { if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return -errno; - - if (child == 0) { + r = safe_fork("(sd-terminal)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return r; + if (r == 0) { int master; pair[0] = safe_close(pair[0]); diff --git a/src/basic/time-util.c b/src/basic/time-util.c index d56576ddbe..95358f8e9f 100644 --- a/src/basic/time-util.c +++ b/src/basic/time-util.c @@ -886,8 +886,8 @@ typedef struct ParseTimestampResult { int parse_timestamp(const char *t, usec_t *usec) { char *last_space, *tz = NULL; ParseTimestampResult *shared, tmp; - int r; pid_t pid; + int r; last_space = strrchr(t, ' '); if (last_space != NULL && timezone_is_valid(last_space + 1)) @@ -900,15 +900,12 @@ int parse_timestamp(const char *t, usec_t *usec) { if (shared == MAP_FAILED) return negative_errno(); - pid = fork(); - - if (pid == -1) { - int fork_errno = errno; + r = safe_fork("(sd-timestamp)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG, &pid); + if (r < 0) { (void) munmap(shared, sizeof *shared); - return -fork_errno; + return r; } - - if (pid == 0) { + if (r == 0) { bool with_tz = true; if (setenv("TZ", tz, 1) != 0) { diff --git a/src/basic/util.c b/src/basic/util.c index 8f9f2b902b..8e431877d0 100644 --- a/src/basic/util.c +++ b/src/basic/util.c @@ -186,11 +186,11 @@ int prot_from_flags(int flags) { int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *path, ...) { bool stdout_is_tty, stderr_is_tty; - pid_t parent_pid, agent_pid; - sigset_t ss, saved_ss; + pid_t agent_pid; unsigned n, i; va_list ap; char **l; + int r; assert(pid); assert(path); @@ -198,45 +198,13 @@ int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *pa /* Spawns a temporary TTY agent, making sure it goes away when * we go away */ - parent_pid = getpid_cached(); - - /* First we temporarily block all signals, so that the new - * child has them blocked initially. This way, we can be sure - * that SIGTERMs are not lost we might send to the agent. */ - assert_se(sigfillset(&ss) >= 0); - assert_se(sigprocmask(SIG_SETMASK, &ss, &saved_ss) >= 0); - - agent_pid = fork(); - if (agent_pid < 0) { - assert_se(sigprocmask(SIG_SETMASK, &saved_ss, NULL) >= 0); - return -errno; - } - - if (agent_pid != 0) { - assert_se(sigprocmask(SIG_SETMASK, &saved_ss, NULL) >= 0); - *pid = agent_pid; + r = safe_fork_full("(sd-agent)", except, n_except, FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_CLOSE_ALL_FDS, &agent_pid); + if (r < 0) + return r; + if (r > 0) return 0; - } - /* In the child: - * - * Make sure the agent goes away when the parent dies */ - if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) - _exit(EXIT_FAILURE); - - /* Make sure we actually can kill the agent, if we need to, in - * case somebody invoked us from a shell script that trapped - * SIGTERM or so... */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - /* Check whether our parent died before we were able - * to set the death signal and unblock the signals */ - if (getppid() != parent_pid) - _exit(EXIT_SUCCESS); - - /* Don't leak fds to the agent */ - close_all_fds(except, n_except); + /* In the child: */ stdout_is_tty = isatty(STDOUT_FILENO); stderr_is_tty = isatty(STDERR_FILENO); diff --git a/src/core/execute.c b/src/core/execute.c index aa9120b2ed..3f3d73272e 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -1207,27 +1207,19 @@ static int setup_pam( parent_pid = getpid_cached(); - pam_pid = fork(); - if (pam_pid < 0) { - r = -errno; + r = safe_fork("(sd-pam)", 0, &pam_pid); + if (r < 0) goto fail; - } - - if (pam_pid == 0) { + if (r == 0) { int sig, ret = EXIT_PAM; /* The child's job is to reset the PAM session on * termination */ barrier_set_role(&barrier, BARRIER_CHILD); - /* This string must fit in 10 chars (i.e. the length - * of "/sbin/init"), to look pretty in /bin/ps */ - rename_process("(sd-pam)"); - - /* Make sure we don't keep open the passed fds in this - child. We assume that otherwise only those fds are - open here that have been opened by PAM. */ - close_many(fds, n_fds); + /* Make sure we don't keep open the passed fds in this child. We assume that otherwise only those fds + * are open here that have been opened by PAM. */ + (void) close_many(fds, n_fds); /* Drop privileges - we don't need any to pam_close_session * and this will make PR_SET_PDEATHSIG work in most cases. @@ -1879,11 +1871,10 @@ static int setup_private_users(uid_t uid, gid_t gid) { if (pipe2(errno_pipe, O_CLOEXEC) < 0) return -errno; - pid = fork(); - if (pid < 0) - return -errno; - - if (pid == 0) { + r = safe_fork("(sd-userns)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return r; + if (r == 0) { _cleanup_close_ int fd = -1; const char *a; pid_t ppid; diff --git a/src/core/shutdown.c b/src/core/shutdown.c index aca89d13d1..9ef4e7787a 100644 --- a/src/core/shutdown.c +++ b/src/core/shutdown.c @@ -221,13 +221,12 @@ static void sync_with_progress(void) { /* Due to the possiblity of the sync operation hanging, we fork * a child process and monitor the progress. If the timeout * lapses, the assumption is that that particular sync stalled. */ - pid = fork(); - if (pid < 0) { - log_error_errno(errno, "Failed to fork: %m"); + r = safe_fork("(sd-sync)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) { + log_error_errno(r, "Failed to fork: %m"); return; } - - if (pid == 0) { + if (r == 0) { /* Start the sync operation here in the child */ sync(); _exit(EXIT_SUCCESS); @@ -492,10 +491,10 @@ int main(int argc, char *argv[]) { log_info("Rebooting with kexec."); - pid = fork(); - if (pid < 0) - log_error_errno(errno, "Failed to fork: %m"); - else if (pid == 0) { + r = safe_fork("(sd-kexec)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) + log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { const char * const args[] = { KEXEC, "-e", NULL @@ -505,8 +504,9 @@ int main(int argc, char *argv[]) { execv(args[0], (char * const *) args); _exit(EXIT_FAILURE); - } else - wait_for_terminate_and_warn("kexec", pid, true); + } + + (void) wait_for_terminate_and_warn("kexec", pid, true); } cmd = RB_AUTOBOOT; diff --git a/src/core/socket.c b/src/core/socket.c index d2c469433d..8e796e9e2c 100644 --- a/src/core/socket.c +++ b/src/core/socket.c @@ -1527,7 +1527,7 @@ static int socket_address_listen_in_cgroup( if (socketpair(AF_UNIX, SOCK_SEQPACKET|SOCK_CLOEXEC, 0, pair) < 0) return log_unit_error_errno(UNIT(s), errno, "Failed to create communication channel: %m"); - r = unit_fork_helper_process(UNIT(s), &pid); + r = unit_fork_helper_process(UNIT(s), "(sd-listen)", &pid); if (r < 0) return log_unit_error_errno(UNIT(s), r, "Failed to fork off listener stub process: %m"); if (r == 0) { @@ -1944,7 +1944,7 @@ static int socket_chown(Socket *s, pid_t *_pid) { /* We have to resolve the user names out-of-process, hence * let's fork here. It's messy, but well, what can we do? */ - r = unit_fork_helper_process(UNIT(s), &pid); + r = unit_fork_helper_process(UNIT(s), "(sd-chown)", &pid); if (r < 0) return r; if (r == 0) { @@ -2871,7 +2871,7 @@ static int socket_accept_in_cgroup(Socket *s, SocketPort *p, int fd) { if (socketpair(AF_UNIX, SOCK_SEQPACKET|SOCK_CLOEXEC, 0, pair) < 0) return log_unit_error_errno(UNIT(s), errno, "Failed to create communication channel: %m"); - r = unit_fork_helper_process(UNIT(s), &pid); + r = unit_fork_helper_process(UNIT(s), "(sd-accept)", &pid); if (r < 0) return log_unit_error_errno(UNIT(s), r, "Failed to fork off accept stub process: %m"); if (r == 0) { diff --git a/src/core/umount.c b/src/core/umount.c index 7f8ddb99ee..d8ccdfd6c2 100644 --- a/src/core/umount.c +++ b/src/core/umount.c @@ -388,11 +388,10 @@ static int remount_with_timeout(MountPoint *m, char *options, int *n_failed) { * fork a child process and set a timeout. If the timeout * lapses, the assumption is that that particular remount * failed. */ - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - - if (pid == 0) { + r = safe_fork("(sd-remount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { log_info("Remounting '%s' read-only in with options '%s'.", m->path, options); /* Start the mount operation here in the child */ @@ -423,11 +422,10 @@ static int umount_with_timeout(MountPoint *m, bool *changed) { * fork a child process and set a timeout. If the timeout * lapses, the assumption is that that particular umount * failed. */ - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - - if (pid == 0) { + r = safe_fork("(sd-umount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { log_info("Unmounting '%s'.", m->path); /* Start the mount operation here in the child Using MNT_FORCE diff --git a/src/core/unit.c b/src/core/unit.c index 7af8425707..652587e6ad 100644 --- a/src/core/unit.c +++ b/src/core/unit.c @@ -21,6 +21,7 @@ #include <errno.h> #include <stdlib.h> #include <string.h> +#include <sys/prctl.h> #include <sys/stat.h> #include <unistd.h> @@ -4968,8 +4969,7 @@ void unit_set_exec_params(Unit *u, ExecParameters *p) { SET_FLAG(p->flags, EXEC_CGROUP_DELEGATE, UNIT_CGROUP_BOOL(u, delegate)); } -int unit_fork_helper_process(Unit *u, pid_t *ret) { - pid_t pid; +int unit_fork_helper_process(Unit *u, const char *name, pid_t *ret) { int r; assert(u); @@ -4980,32 +4980,24 @@ int unit_fork_helper_process(Unit *u, pid_t *ret) { (void) unit_realize_cgroup(u); - pid = fork(); - if (pid < 0) - return -errno; - - if (pid == 0) { + r = safe_fork(name, FORK_REOPEN_LOG, ret); + if (r != 0) + return r; - (void) default_signals(SIGNALS_CRASH_HANDLER, SIGNALS_IGNORE, -1); - (void) ignore_signals(SIGPIPE, -1); + (void) default_signals(SIGNALS_CRASH_HANDLER, SIGNALS_IGNORE, -1); + (void) ignore_signals(SIGPIPE, -1); - log_close(); - log_open(); + (void) prctl(PR_SET_PDEATHSIG, SIGTERM); - if (u->cgroup_path) { - r = cg_attach_everywhere(u->manager->cgroup_supported, u->cgroup_path, 0, NULL, NULL); - if (r < 0) { - log_unit_error_errno(u, r, "Failed to join unit cgroup %s: %m", u->cgroup_path); - _exit(EXIT_CGROUP); - } + if (u->cgroup_path) { + r = cg_attach_everywhere(u->manager->cgroup_supported, u->cgroup_path, 0, NULL, NULL); + if (r < 0) { + log_unit_error_errno(u, r, "Failed to join unit cgroup %s: %m", u->cgroup_path); + _exit(EXIT_CGROUP); } - - *ret = getpid_cached(); - return 0; } - *ret = pid; - return 1; + return 0; } static void unit_update_dependency_mask(Unit *u, UnitDependency d, Unit *other, UnitDependencyInfo di) { diff --git a/src/core/unit.h b/src/core/unit.h index fdd82315ba..80585ac1c8 100644 --- a/src/core/unit.h +++ b/src/core/unit.h @@ -782,7 +782,7 @@ bool unit_shall_confirm_spawn(Unit *u); void unit_set_exec_params(Unit *s, ExecParameters *p); -int unit_fork_helper_process(Unit *u, pid_t *ret); +int unit_fork_helper_process(Unit *u, const char *name, pid_t *ret); void unit_remove_dependencies(Unit *u, UnitDependencyMask mask); diff --git a/src/coredump/coredumpctl.c b/src/coredump/coredumpctl.c index 2fd5adcddc..5013758909 100644 --- a/src/coredump/coredumpctl.c +++ b/src/coredump/coredumpctl.c @@ -928,17 +928,13 @@ static int run_gdb(sd_journal *j) { /* Don't interfere with gdb and its handling of SIGINT. */ (void) ignore_signals(SIGINT, -1); - pid = fork(); - if (pid < 0) { - r = log_error_errno(errno, "Failed to fork(): %m"); + r = safe_fork("(gdb)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) { + log_error_errno(r, "Failed to fork(): %m"); goto finish; } - if (pid == 0) { - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - + if (r == 0) { execlp("gdb", "gdb", exe, path, NULL); - log_error_errno(errno, "Failed to invoke gdb: %m"); _exit(1); } diff --git a/src/delta/delta.c b/src/delta/delta.c index d286881698..8ebfbf441a 100644 --- a/src/delta/delta.c +++ b/src/delta/delta.c @@ -161,8 +161,8 @@ static int notify_override_unchanged(const char *f) { static int found_override(const char *top, const char *bottom) { _cleanup_free_ char *dest = NULL; - int k; pid_t pid; + int r; assert(top); assert(bottom); @@ -170,31 +170,26 @@ static int found_override(const char *top, const char *bottom) { if (null_or_empty_path(top) > 0) return notify_override_masked(top, bottom); - k = readlink_malloc(top, &dest); - if (k >= 0) { + r = readlink_malloc(top, &dest); + if (r >= 0) { if (equivalent(dest, bottom) > 0) return notify_override_equivalent(top, bottom); else return notify_override_redirected(top, bottom); } - k = notify_override_overridden(top, bottom); + r = notify_override_overridden(top, bottom); if (!arg_diff) - return k; + return r; putchar('\n'); fflush(stdout); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork off diff: %m"); - else if (pid == 0) { - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - + r = safe_fork("(diff)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) + return log_error_errno(pid, "Failed to fork off diff: %m"); + if (r == 0) { execlp("diff", "diff", "-us", "--", bottom, top, NULL); log_error_errno(errno, "Failed to execute diff: %m"); _exit(EXIT_FAILURE); @@ -203,7 +198,7 @@ static int found_override(const char *top, const char *bottom) { wait_for_terminate_and_warn("diff", pid, false); putchar('\n'); - return k; + return r; } static int enumerate_dir_d( diff --git a/src/fsck/fsck.c b/src/fsck/fsck.c index 0091e388dc..818d581c30 100644 --- a/src/fsck/fsck.c +++ b/src/fsck/fsck.c @@ -392,12 +392,12 @@ int main(int argc, char *argv[]) { } } - pid = fork(); - if (pid < 0) { - r = log_error_errno(errno, "fork(): %m"); + r = safe_fork("(fsck)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) { + log_error_errno(r, "fork(): %m"); goto finish; } - if (pid == 0) { + if (r == 0) { char dash_c[STRLEN("-C") + DECIMAL_STR_MAX(int) + 1]; int progress_socket = -1; const char *cmdline[9]; @@ -405,10 +405,6 @@ int main(int argc, char *argv[]) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - /* Close the reading side of the progress pipe */ progress_pipe[0] = safe_close(progress_pipe[0]); diff --git a/src/import/import-common.c b/src/import/import-common.c index 2f989a171c..1efbda9787 100644 --- a/src/import/import-common.c +++ b/src/import/import-common.c @@ -82,11 +82,10 @@ int import_fork_tar_x(const char *path, pid_t *ret) { if (pipe2(pipefd, O_CLOEXEC) < 0) return log_error_errno(errno, "Failed to create pipe for tar: %m"); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork off tar: %m"); - - if (pid == 0) { + r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork off tar: %m"); + if (r == 0) { int null_fd; uint64_t retain = (1ULL << CAP_CHOWN) | @@ -98,10 +97,6 @@ int import_fork_tar_x(const char *path, pid_t *ret) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - pipefd[1] = safe_close(pipefd[1]); r = move_fd(pipefd[0], STDIN_FILENO, false); @@ -156,20 +151,15 @@ int import_fork_tar_c(const char *path, pid_t *ret) { if (pipe2(pipefd, O_CLOEXEC) < 0) return log_error_errno(errno, "Failed to create pipe for tar: %m"); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork off tar: %m"); - - if (pid == 0) { + r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork off tar: %m"); + if (r == 0) { int null_fd; uint64_t retain = (1ULL << CAP_DAC_OVERRIDE); /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - pipefd[0] = safe_close(pipefd[0]); r = move_fd(pipefd[1], STDOUT_FILENO, false); diff --git a/src/import/importd.c b/src/import/importd.c index 9c7694c0ad..21af09fc45 100644 --- a/src/import/importd.c +++ b/src/import/importd.c @@ -371,10 +371,10 @@ static int transfer_start(Transfer *t) { if (pipe2(pipefd, O_CLOEXEC) < 0) return -errno; - t->pid = fork(); - if (t->pid < 0) - return -errno; - if (t->pid == 0) { + r = safe_fork("(sd-transfer)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &t->pid); + if (r < 0) + return r; + if (r == 0) { const char *cmd[] = { NULL, /* systemd-import, systemd-export or systemd-pull */ NULL, /* tar, raw */ @@ -393,10 +393,6 @@ static int transfer_start(Transfer *t) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - pipefd[0] = safe_close(pipefd[0]); if (dup2(pipefd[1], STDERR_FILENO) != STDERR_FILENO) { diff --git a/src/import/pull-common.c b/src/import/pull-common.c index c2a3a6aa8b..6acd264af5 100644 --- a/src/import/pull-common.c +++ b/src/import/pull-common.c @@ -463,10 +463,10 @@ int pull_verify(PullJob *main_job, gpg_home_created = true; - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork off gpg: %m"); - if (pid == 0) { + r = safe_fork("(gpg)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork off gpg: %m"); + if (r == 0) { const char *cmd[] = { "gpg", "--no-options", @@ -487,10 +487,6 @@ int pull_verify(PullJob *main_job, /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - gpg_pipe[1] = safe_close(gpg_pipe[1]); r = move_fd(gpg_pipe[0], STDIN_FILENO, false); diff --git a/src/journal-remote/journal-remote.c b/src/journal-remote/journal-remote.c index e44989e1ba..32416493fd 100644 --- a/src/journal-remote/journal-remote.c +++ b/src/journal-remote/journal-remote.c @@ -81,27 +81,20 @@ static bool arg_trust_all = false; **********************************************************************/ static int spawn_child(const char* child, char** argv) { - int fd[2]; - pid_t parent_pid, child_pid; - int r; + pid_t child_pid; + int fd[2], r; if (pipe(fd) < 0) return log_error_errno(errno, "Failed to create pager pipe: %m"); - parent_pid = getpid_cached(); - - child_pid = fork(); - if (child_pid < 0) { - r = log_error_errno(errno, "Failed to fork: %m"); + r = safe_fork("(remote)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child_pid); + if (r < 0) { safe_close_pair(fd); - return r; + return log_error_errno(r, "Failed to fork: %m"); } /* In the child */ - if (child_pid == 0) { - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); + if (r == 0) { r = dup2(fd[1], STDOUT_FILENO); if (r < 0) { @@ -111,15 +104,6 @@ static int spawn_child(const char* child, char** argv) { safe_close_pair(fd); - /* 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); - execvp(child, argv); log_error_errno(errno, "Failed to exec child %s: %m", child); _exit(EXIT_FAILURE); diff --git a/src/libsystemd/sd-bus/bus-container.c b/src/libsystemd/sd-bus/bus-container.c index 8f6d34838e..a1242c5678 100644 --- a/src/libsystemd/sd-bus/bus-container.c +++ b/src/libsystemd/sd-bus/bus-container.c @@ -62,11 +62,10 @@ int bus_container_connect_socket(sd_bus *b) { if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return -errno; - - if (child == 0) { + r = safe_fork("(sd-buscntr)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return r; + if (r == 0) { pid_t grandchild; pair[0] = safe_close(pair[0]); @@ -82,11 +81,10 @@ int bus_container_connect_socket(sd_bus *b) { * comes from a process from within the container, and * not outside of it */ - grandchild = fork(); - if (grandchild < 0) + r = safe_fork("(sd-buscntr2)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &grandchild); + if (r < 0) _exit(EXIT_FAILURE); - - if (grandchild == 0) { + if (r == 0) { r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size); if (r < 0) { diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c index d72cb616e0..013bdb05a0 100644 --- a/src/libsystemd/sd-bus/bus-socket.c +++ b/src/libsystemd/sd-bus/bus-socket.c @@ -715,19 +715,14 @@ int bus_socket_exec(sd_bus *b) { if (r < 0) return -errno; - pid = fork(); - if (pid < 0) { + r = safe_fork_full("(sd-busexec)", s+1, 1, FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) { safe_close_pair(s); - return -errno; + return r; } - if (pid == 0) { + if (r == 0) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - close_all_fds(s+1, 1); - assert_se(dup3(s[1], STDIN_FILENO, 0) == STDIN_FILENO); assert_se(dup3(s[1], STDOUT_FILENO, 0) == STDOUT_FILENO); diff --git a/src/login/inhibit.c b/src/login/inhibit.c index 7b9e3f0f6e..9117a70481 100644 --- a/src/login/inhibit.c +++ b/src/login/inhibit.c @@ -266,20 +266,13 @@ int main(int argc, char *argv[]) { return EXIT_FAILURE; } - pid = fork(); - if (pid < 0) { - log_error_errno(errno, "Failed to fork: %m"); + r = safe_fork("(inhibit)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) { + log_error_errno(r, "Failed to fork: %m"); return EXIT_FAILURE; } - - if (pid == 0) { + if (r == 0) { /* Child */ - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - close_all_fds(NULL, 0); - execvp(argv[optind], argv + optind); log_error_errno(errno, "Failed to execute %s: %m", argv[optind]); _exit(EXIT_FAILURE); diff --git a/src/machine/image-dbus.c b/src/machine/image-dbus.c index 10d1b06016..8ba1380c81 100644 --- a/src/machine/image-dbus.c +++ b/src/machine/image-dbus.c @@ -75,10 +75,10 @@ int bus_image_method_remove( if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0) return sd_bus_error_set_errnof(error, errno, "Failed to create pipe: %m"); - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - if (child == 0) { + r = safe_fork("(sd-imgrm)", FORK_RESET_SIGNALS, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { errno_pipe_fd[0] = safe_close(errno_pipe_fd[0]); r = image_remove(image); @@ -187,10 +187,10 @@ int bus_image_method_clone( if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0) return sd_bus_error_set_errnof(error, errno, "Failed to create pipe: %m"); - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - if (child == 0) { + r = safe_fork("(imgclone)", FORK_RESET_SIGNALS, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { errno_pipe_fd[0] = safe_close(errno_pipe_fd[0]); r = image_clone(image, new_name, read_only); diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c index 2d3d285849..68e0b7edcc 100644 --- a/src/machine/machine-dbus.c +++ b/src/machine/machine-dbus.c @@ -250,11 +250,10 @@ int bus_machine_method_get_addresses(sd_bus_message *message, void *userdata, sd if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - - if (child == 0) { + r = safe_fork("(sd-addr)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { _cleanup_free_ struct local_address *addresses = NULL; struct local_address *a; int i, n; @@ -390,11 +389,10 @@ int bus_machine_method_get_os_release(sd_bus_message *message, void *userdata, s if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - - if (child == 0) { + r = safe_fork("(sd-osrel)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { int fd = -1; pair[0] = safe_close(pair[0]); @@ -997,13 +995,12 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu goto finish; } - child = fork(); - if (child < 0) { - r = sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); + r = safe_fork("(sd-bindmnt)", FORK_RESET_SIGNALS, &child); + if (r < 0) { + sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); goto finish; } - - if (child == 0) { + if (r == 0) { const char *mount_inside; int mntfd; const char *q; @@ -1172,11 +1169,10 @@ int bus_machine_method_copy(sd_bus_message *message, void *userdata, sd_bus_erro if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0) return sd_bus_error_set_errnof(error, errno, "Failed to create pipe: %m"); - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - - if (child == 0) { + r = safe_fork("(sd-copy)", FORK_RESET_SIGNALS, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { int containerfd; const char *q; int mntfd; @@ -1282,11 +1278,10 @@ int bus_machine_method_open_root_directory(sd_bus_message *message, void *userda if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - - if (child == 0) { + r = safe_fork("(sd-openroot)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { _cleanup_close_ int dfd = -1; pair[0] = safe_close(pair[0]); diff --git a/src/machine/machined-dbus.c b/src/machine/machined-dbus.c index 330d6b3d6e..c5e59c4716 100644 --- a/src/machine/machined-dbus.c +++ b/src/machine/machined-dbus.c @@ -1078,11 +1078,10 @@ static int method_clean_pool(sd_bus_message *message, void *userdata, sd_bus_err return -errno; /* This might be a slow operation, run it asynchronously in a background process */ - child = fork(); - if (child < 0) - return sd_bus_error_set_errnof(error, errno, "Failed to fork(): %m"); - - if (child == 0) { + r = safe_fork("(sd-clean)", FORK_RESET_SIGNALS, &child); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to fork(): %m"); + if (r == 0) { _cleanup_(image_hashmap_freep) Hashmap *images = NULL; bool success = true; Image *image; diff --git a/src/nspawn/nspawn-setuid.c b/src/nspawn/nspawn-setuid.c index 31f5dd3cdd..3d9e23ec1f 100644 --- a/src/nspawn/nspawn-setuid.c +++ b/src/nspawn/nspawn-setuid.c @@ -33,7 +33,7 @@ #include "util.h" static int spawn_getent(const char *database, const char *key, pid_t *rpid) { - int pipe_fds[2]; + int pipe_fds[2], r; pid_t pid; assert(database); @@ -43,10 +43,10 @@ static int spawn_getent(const char *database, const char *key, pid_t *rpid) { if (pipe2(pipe_fds, O_CLOEXEC) < 0) return log_error_errno(errno, "Failed to allocate pipe: %m"); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork getent child: %m"); - else if (pid == 0) { + r = safe_fork("(getent)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork getent child: %m"); + if (r == 0) { int nullfd; char *empty_env = NULL; @@ -71,8 +71,6 @@ static int spawn_getent(const char *database, const char *key, pid_t *rpid) { if (nullfd > 2) safe_close(nullfd); - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); close_all_fds(NULL, 0); execle("/usr/bin/getent", "getent", database, key, NULL, &empty_env); diff --git a/src/nspawn/nspawn-stub-pid1.c b/src/nspawn/nspawn-stub-pid1.c index bb87eb1b62..58f4636866 100644 --- a/src/nspawn/nspawn-stub-pid1.c +++ b/src/nspawn/nspawn-stub-pid1.c @@ -93,7 +93,7 @@ int stub_pid1(sd_id128_t uuid) { sd_id128_to_string(uuid, new_environment + sizeof(new_environment) - SD_ID128_STRING_MAX); reset_environ(new_environment, sizeof(new_environment)); - rename_process("STUBINIT"); + (void) rename_process("(sd-stubinit)"); assert_se(sigemptyset(&waitmask) >= 0); assert_se(sigset_add_many(&waitmask, diff --git a/src/partition/makefs.c b/src/partition/makefs.c index e5e125255b..872cf0dfd1 100644 --- a/src/partition/makefs.c +++ b/src/partition/makefs.c @@ -34,6 +34,7 @@ static int makefs(const char *type, const char *device) { const char *mkfs; pid_t pid; + int r; if (streq(type, "swap")) mkfs = "/sbin/mkswap"; @@ -42,19 +43,14 @@ static int makefs(const char *type, const char *device) { if (access(mkfs, X_OK) != 0) return log_error_errno(errno, "%s is not executable: %m", mkfs); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "fork(): %m"); - - if (pid == 0) { + r = safe_fork("(fsck)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "fork(): %m"); + if (r == 0) { const char *cmdline[3] = { mkfs, device, NULL }; /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - execv(cmdline[0], (char**) cmdline); _exit(EXIT_FAILURE); } diff --git a/src/quotacheck/quotacheck.c b/src/quotacheck/quotacheck.c index ec5be21a34..b5636e69d4 100644 --- a/src/quotacheck/quotacheck.c +++ b/src/quotacheck/quotacheck.c @@ -106,19 +106,15 @@ int main(int argc, char *argv[]) { return EXIT_SUCCESS; } - pid = fork(); - if (pid < 0) { - r = log_error_errno(errno, "fork(): %m"); + r = safe_fork("(quotacheck)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) { + log_error_errno(r, "fork(): %m"); goto finish; } - if (pid == 0) { + if (r == 0) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - execv(cmdline[0], (char**) cmdline); _exit(1); /* Operational error */ } diff --git a/src/remount-fs/remount-fs.c b/src/remount-fs/remount-fs.c index 2d7cf723f4..1f0397cf6f 100644 --- a/src/remount-fs/remount-fs.c +++ b/src/remount-fs/remount-fs.c @@ -87,19 +87,14 @@ int main(int argc, char *argv[]) { log_debug("Remounting %s", me->mnt_dir); - pid = fork(); - if (pid < 0) { - r = log_error_errno(errno, "Failed to fork: %m"); + r = safe_fork("(remount)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) { + log_error_errno(r, "Failed to fork: %m"); goto finish; } - - if (pid == 0) { + if (r == 0) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - (void) prctl(PR_SET_PDEATHSIG, SIGTERM); - execv(MOUNT_PATH, STRV_MAKE(MOUNT_PATH, me->mnt_dir, "-o", "remount")); log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m"); diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c index af7f8f345e..ffb921e4a8 100644 --- a/src/shared/logs-show.c +++ b/src/shared/logs-show.c @@ -1278,11 +1278,10 @@ static int get_boot_id_for_machine(const char *machine, sd_id128_t *boot_id) { if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) return -errno; - child = fork(); - if (child < 0) - return -errno; - - if (child == 0) { + r = safe_fork("(sd-bootid)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child); + if (r < 0) + return r; + if (r == 0) { int fd; pair[0] = safe_close(pair[0]); diff --git a/src/shared/machine-pool.c b/src/shared/machine-pool.c index e7d19b10aa..fb8a6e2fd7 100644 --- a/src/shared/machine-pool.c +++ b/src/shared/machine-pool.c @@ -123,20 +123,15 @@ static int setup_machine_raw(uint64_t size, sd_bus_error *error) { goto fail; } - pid = fork(); - if (pid < 0) { - r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m"); + r = safe_fork("(mkfs)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) { + sd_bus_error_set_errnof(error, r, "Failed to fork mkfs.btrfs: %m"); goto fail; } - - if (pid == 0) { + if (r == 0) { /* Child */ - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - fd = safe_close(fd); execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL); diff --git a/src/shared/pager.c b/src/shared/pager.c index 39997278f1..17e0121a66 100644 --- a/src/shared/pager.c +++ b/src/shared/pager.c @@ -62,7 +62,7 @@ static bool stderr_redirected = false; int pager_open(bool no_pager, bool jump_to_end) { _cleanup_close_pair_ int fd[2] = { -1, -1 }; const char *pager; - pid_t parent_pid; + int r; if (no_pager) return 0; @@ -89,18 +89,13 @@ int pager_open(bool no_pager, bool jump_to_end) { if (pipe2(fd, O_CLOEXEC) < 0) return log_error_errno(errno, "Failed to create pager pipe: %m"); - parent_pid = getpid_cached(); - - pager_pid = fork(); - if (pager_pid < 0) - return log_error_errno(errno, "Failed to fork pager: %m"); - - /* In the child start the pager */ - if (pager_pid == 0) { + r = safe_fork("(pager)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pager_pid); + if (r < 0) + return log_error_errno(r, "Failed to fork pager: %m"); + if (r == 0) { const char* less_opts, *less_charset; - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); + /* In the child start the pager */ (void) dup2(fd[0], STDIN_FILENO); safe_close_pair(fd); @@ -124,15 +119,6 @@ int pager_open(bool no_pager, bool jump_to_end) { setenv("LESSCHARSET", less_charset, 1) < 0) _exit(EXIT_FAILURE); - /* Make sure the pager 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); - if (pager) { execlp(pager, pager, NULL); execl("/bin/sh", "sh", "-c", pager, NULL); @@ -222,24 +208,11 @@ int show_man_page(const char *desc, bool null_stdio) { } else args[1] = desc; - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - - if (pid == 0) { + r = safe_fork("(man)", FORK_RESET_SIGNALS|FORK_DEATHSIG|(null_stdio ? FORK_NULL_STDIO : 0), &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { /* Child */ - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - - if (null_stdio) { - r = make_null_stdio(); - if (r < 0) { - log_error_errno(r, "Failed to kill stdio: %m"); - _exit(EXIT_FAILURE); - } - } - execvp(args[0], (char**) args); log_error_errno(errno, "Failed to execute man: %m"); _exit(EXIT_FAILURE); diff --git a/src/sulogin-shell/sulogin-shell.c b/src/sulogin-shell/sulogin-shell.c index 70659df417..a6e0e0476f 100644 --- a/src/sulogin-shell/sulogin-shell.c +++ b/src/sulogin-shell/sulogin-shell.c @@ -81,18 +81,13 @@ static int start_default_target(sd_bus *bus) { static int fork_wait(const char* const cmdline[]) { pid_t pid; + int r; - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "fork(): %m"); - if (pid == 0) { - + r = safe_fork("(sulogin)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "fork(): %m"); + if (r == 0) { /* Child */ - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - execv(cmdline[0], (char**) cmdline); log_error_errno(errno, "Failed to execute %s: %m", cmdline[0]); _exit(EXIT_FAILURE); /* Operational error */ diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c index 45e2750c0c..61ce1d0290 100644 --- a/src/systemctl/systemctl.c +++ b/src/systemctl/systemctl.c @@ -3539,10 +3539,10 @@ static int load_kexec_kernel(void) { if (arg_dry_run) return 0; - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - else if (pid == 0) { + r = safe_fork("(kexec)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { const char* const args[] = { KEXEC, @@ -3552,15 +3552,11 @@ static int load_kexec_kernel(void) { NULL }; /* Child */ - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); - execv(args[0], (char * const *) args); _exit(EXIT_FAILURE); - } else - return wait_for_terminate_and_warn("kexec", pid, true); + } + + return wait_for_terminate_and_warn("kexec", pid, true); } static int set_exit_code(uint8_t code) { @@ -6123,15 +6119,11 @@ static int enable_sysv_units(const char *verb, char **args) { if (!arg_quiet) log_info("Executing: %s", l); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - else if (pid == 0) { + j = safe_fork("(sysv)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (j < 0) + return log_error_errno(j, "Failed to fork: %m"); + if (j == 0) { /* Child */ - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - execv(argv[0], (char**) argv); log_error_errno(errno, "Failed to execute %s: %m", argv[0]); _exit(EXIT_FAILURE); @@ -7000,20 +6992,16 @@ static int run_editor(char **paths) { assert(paths); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - - if (pid == 0) { + r = safe_fork("(editor)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { const char **args; char *editor, **editor_args = NULL; char **tmp_path, **original_path, *p; unsigned n_editor_args = 0, i = 1; size_t argc; - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - argc = strv_length(paths)/2 + 1; /* SYSTEMD_EDITOR takes precedence over EDITOR which takes precedence over VISUAL diff --git a/src/test/test-process-util.c b/src/test/test-process-util.c index a38f917961..2e262dd15b 100644 --- a/src/test/test-process-util.c +++ b/src/test/test-process-util.c @@ -38,6 +38,7 @@ #include "macro.h" #include "parse-util.h" #include "process-util.h" +#include "signal-util.h" #include "stdio-util.h" #include "string-util.h" #include "terminal-util.h" @@ -497,6 +498,28 @@ static void test_getpid_measure(void) { log_info("getpid_cached(): %llu/s\n", (unsigned long long) (MEASURE_ITERATIONS*USEC_PER_SEC/q)); } +static void test_safe_fork(void) { + siginfo_t status; + pid_t pid; + int r; + + BLOCK_SIGNALS(SIGCHLD); + + r = safe_fork("(test-child)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG|FORK_NULL_STDIO|FORK_REOPEN_LOG, &pid); + assert_se(r >= 0); + + if (r == 0) { + /* child */ + usleep(100 * USEC_PER_MSEC); + + _exit(88); + } + + assert_se(wait_for_terminate(pid, &status) >= 0); + assert_se(status.si_code == CLD_EXITED); + assert_se(status.si_status == 88); +} + int main(int argc, char *argv[]) { log_set_max_level(LOG_DEBUG); @@ -523,6 +546,7 @@ int main(int argc, char *argv[]) { test_rename_process(); test_getpid_cached(); test_getpid_measure(); + test_safe_fork(); return 0; } diff --git a/src/tty-ask-password-agent/tty-ask-password-agent.c b/src/tty-ask-password-agent/tty-ask-password-agent.c index 1553655a28..8edd891c86 100644 --- a/src/tty-ask-password-agent/tty-ask-password-agent.c +++ b/src/tty-ask-password-agent/tty-ask-password-agent.c @@ -693,11 +693,13 @@ static int parse_argv(int argc, char *argv[]) { * If one of the tasks does handle a password, the remaining tasks * will be terminated. */ -static int ask_on_this_console(const char *tty, pid_t *pid, int argc, char *argv[]) { +static int ask_on_this_console(const char *tty, pid_t *ret_pid, int argc, char *argv[]) { struct sigaction sig = { .sa_handler = nop_signal_handler, .sa_flags = SA_NOCLDSTOP | SA_RESTART, }; + pid_t pid; + int r; assert_se(sigprocmask_many(SIG_UNBLOCK, NULL, SIGHUP, SIGCHLD, -1) >= 0); @@ -707,18 +709,14 @@ static int ask_on_this_console(const char *tty, pid_t *pid, int argc, char *argv sig.sa_handler = SIG_DFL; assert_se(sigaction(SIGHUP, &sig, NULL) >= 0); - *pid = fork(); - if (*pid < 0) - return log_error_errno(errno, "Failed to fork process: %m"); - - if (*pid == 0) { + r = safe_fork("(sd-passwd)", FORK_RESET_SIGNALS, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork process: %m"); + if (r == 0) { int ac; assert_se(prctl(PR_SET_PDEATHSIG, SIGHUP) >= 0); - reset_signal_mask(); - reset_all_signal_handlers(); - for (ac = 0; ac < argc; ac++) { if (streq(argv[ac], "--console")) { argv[ac] = strjoina("--console=", tty); @@ -731,6 +729,8 @@ static int ask_on_this_console(const char *tty, pid_t *pid, int argc, char *argv execv(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, argv); _exit(EXIT_FAILURE); } + + *ret_pid = pid; return 0; } diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c index 8f7c28f03d..8506e67d6e 100644 --- a/src/udev/udev-event.c +++ b/src/udev/udev-event.c @@ -774,10 +774,12 @@ int udev_event_spawn(struct udev_event *event, } } - pid = fork(); - switch(pid) { - case 0: - { + err = safe_fork("(spawn)", FORK_RESET_SIGNALS, &pid); + if (err < 0) { + log_error_errno(err, "fork of '%s' failed: %m", cmd); + goto out; + } + if (err == 0) { char arg[UTIL_PATH_SIZE]; char *argv[128]; char program[UTIL_PATH_SIZE]; @@ -802,23 +804,18 @@ int udev_event_spawn(struct udev_event *event, _exit(2); } - case -1: - log_error_errno(errno, "fork of '%s' failed: %m", cmd); - err = -1; - goto out; - default: - /* parent closed child's ends of pipes */ - outpipe[WRITE_END] = safe_close(outpipe[WRITE_END]); - errpipe[WRITE_END] = safe_close(errpipe[WRITE_END]); - spawn_read(event, - timeout_usec, - cmd, - outpipe[READ_END], errpipe[READ_END], - result, ressize); + /* parent closed child's ends of pipes */ + outpipe[WRITE_END] = safe_close(outpipe[WRITE_END]); + errpipe[WRITE_END] = safe_close(errpipe[WRITE_END]); - err = spawn_wait(event, timeout_usec, timeout_warn_usec, cmd, pid, accept_failure); - } + spawn_read(event, + timeout_usec, + cmd, + outpipe[READ_END], errpipe[READ_END], + result, ressize); + + err = spawn_wait(event, timeout_usec, timeout_warn_usec, cmd, pid, accept_failure); out: if (outpipe[READ_END] >= 0) diff --git a/src/vconsole/vconsole-setup.c b/src/vconsole/vconsole-setup.c index e19a1637bf..fdc7c5f974 100644 --- a/src/vconsole/vconsole-setup.c +++ b/src/vconsole/vconsole-setup.c @@ -133,6 +133,7 @@ static int keyboard_load_and_wait(const char *vc, const char *map, const char *m const char *args[8]; unsigned i = 0; pid_t pid; + int r; /* An empty map means kernel map */ if (isempty(map)) @@ -152,14 +153,10 @@ static int keyboard_load_and_wait(const char *vc, const char *map, const char *m log_debug("Executing \"%s\"...", strnull((cmd = strv_join((char**) args, " ")))); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - else if (pid == 0) { - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - + r = safe_fork("(loadkeys)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { execv(args[0], (char **) args); _exit(EXIT_FAILURE); } @@ -172,6 +169,7 @@ static int font_load_and_wait(const char *vc, const char *font, const char *map, const char *args[9]; unsigned i = 0; pid_t pid; + int r; /* Any part can be set independently */ if (isempty(font) && isempty(map) && isempty(unimap)) @@ -195,14 +193,10 @@ static int font_load_and_wait(const char *vc, const char *font, const char *map, log_debug("Executing \"%s\"...", strnull((cmd = strv_join((char**) args, " ")))); - pid = fork(); - if (pid < 0) - return log_error_errno(errno, "Failed to fork: %m"); - else if (pid == 0) { - - (void) reset_all_signal_handlers(); - (void) reset_signal_mask(); - + r = safe_fork("(setfont)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork: %m"); + if (r == 0) { execv(args[0], (char **) args); _exit(EXIT_FAILURE); } |