diff options
Diffstat (limited to 'src/udev/udev-spawn.c')
| -rw-r--r-- | src/udev/udev-spawn.c | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/src/udev/udev-spawn.c b/src/udev/udev-spawn.c new file mode 100644 index 0000000..67a3005 --- /dev/null +++ b/src/udev/udev-spawn.c @@ -0,0 +1,355 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include "sd-event.h" + +#include "device-private.h" +#include "device-util.h" +#include "fd-util.h" +#include "path-util.h" +#include "process-util.h" +#include "signal-util.h" +#include "string-util.h" +#include "strv.h" +#include "udev-builtin.h" +#include "udev-event.h" +#include "udev-spawn.h" +#include "udev-trace.h" + +typedef struct Spawn { + sd_device *device; + const char *cmd; + pid_t pid; + usec_t timeout_warn_usec; + usec_t timeout_usec; + int timeout_signal; + usec_t event_birth_usec; + bool accept_failure; + int fd_stdout; + int fd_stderr; + char *result; + size_t result_size; + size_t result_len; + bool truncated; +} Spawn; + +static int on_spawn_io(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + Spawn *spawn = ASSERT_PTR(userdata); + char buf[4096], *p; + size_t size; + ssize_t l; + int r; + + assert(fd == spawn->fd_stdout || fd == spawn->fd_stderr); + assert(!spawn->result || spawn->result_len < spawn->result_size); + + if (fd == spawn->fd_stdout && spawn->result) { + p = spawn->result + spawn->result_len; + size = spawn->result_size - spawn->result_len; + } else { + p = buf; + size = sizeof(buf); + } + + l = read(fd, p, size - (p == buf)); + if (l < 0) { + if (errno == EAGAIN) + goto reenable; + + log_device_error_errno(spawn->device, errno, + "Failed to read stdout of '%s': %m", spawn->cmd); + + return 0; + } + + if ((size_t) l == size) { + log_device_warning(spawn->device, "Truncating stdout of '%s' up to %zu byte.", + spawn->cmd, spawn->result_size); + l--; + spawn->truncated = true; + } + + p[l] = '\0'; + if (fd == spawn->fd_stdout && spawn->result) + spawn->result_len += l; + + /* Log output only if we watch stderr. */ + if (l > 0 && spawn->fd_stderr >= 0) { + _cleanup_strv_free_ char **v = NULL; + + r = strv_split_newlines_full(&v, p, EXTRACT_RETAIN_ESCAPE); + if (r < 0) + log_device_debug(spawn->device, + "Failed to split output from '%s'(%s), ignoring: %m", + spawn->cmd, fd == spawn->fd_stdout ? "out" : "err"); + + STRV_FOREACH(q, v) + log_device_debug(spawn->device, "'%s'(%s) '%s'", spawn->cmd, + fd == spawn->fd_stdout ? "out" : "err", *q); + } + + if (l == 0 || spawn->truncated) + return 0; + +reenable: + /* Re-enable the event source if we did not encounter EOF */ + + r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT); + if (r < 0) + log_device_error_errno(spawn->device, r, + "Failed to reactivate IO source of '%s'", spawn->cmd); + return 0; +} + +static int on_spawn_timeout(sd_event_source *s, uint64_t usec, void *userdata) { + Spawn *spawn = ASSERT_PTR(userdata); + + DEVICE_TRACE_POINT(spawn_timeout, spawn->device, spawn->cmd); + + kill_and_sigcont(spawn->pid, spawn->timeout_signal); + + log_device_error(spawn->device, "Spawned process '%s' ["PID_FMT"] timed out after %s, killing", + spawn->cmd, spawn->pid, + FORMAT_TIMESPAN(spawn->timeout_usec, USEC_PER_SEC)); + + return 1; +} + +static int on_spawn_timeout_warning(sd_event_source *s, uint64_t usec, void *userdata) { + Spawn *spawn = ASSERT_PTR(userdata); + + log_device_warning(spawn->device, "Spawned process '%s' ["PID_FMT"] is taking longer than %s to complete", + spawn->cmd, spawn->pid, + FORMAT_TIMESPAN(spawn->timeout_warn_usec, USEC_PER_SEC)); + + return 1; +} + +static int on_spawn_sigchld(sd_event_source *s, const siginfo_t *si, void *userdata) { + Spawn *spawn = ASSERT_PTR(userdata); + int ret = -EIO; + + switch (si->si_code) { + case CLD_EXITED: + if (si->si_status == 0) + log_device_debug(spawn->device, "Process '%s' succeeded.", spawn->cmd); + else + log_device_full(spawn->device, spawn->accept_failure ? LOG_DEBUG : LOG_WARNING, + "Process '%s' failed with exit code %i.", spawn->cmd, si->si_status); + ret = si->si_status; + break; + case CLD_KILLED: + case CLD_DUMPED: + log_device_error(spawn->device, "Process '%s' terminated by signal %s.", spawn->cmd, signal_to_string(si->si_status)); + break; + default: + log_device_error(spawn->device, "Process '%s' failed due to unknown reason.", spawn->cmd); + } + + DEVICE_TRACE_POINT(spawn_exit, spawn->device, spawn->cmd); + + sd_event_exit(sd_event_source_get_event(s), ret); + return 1; +} + +static int spawn_wait(Spawn *spawn) { + _cleanup_(sd_event_unrefp) sd_event *e = NULL; + _cleanup_(sd_event_source_disable_unrefp) sd_event_source *sigchld_source = NULL; + _cleanup_(sd_event_source_disable_unrefp) sd_event_source *stdout_source = NULL; + _cleanup_(sd_event_source_disable_unrefp) sd_event_source *stderr_source = NULL; + int r; + + assert(spawn); + + r = sd_event_new(&e); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to allocate sd-event object: %m"); + + if (spawn->timeout_usec > 0) { + usec_t usec, age_usec; + + usec = now(CLOCK_MONOTONIC); + age_usec = usec - spawn->event_birth_usec; + if (age_usec < spawn->timeout_usec) { + if (spawn->timeout_warn_usec > 0 && + spawn->timeout_warn_usec < spawn->timeout_usec && + spawn->timeout_warn_usec > age_usec) { + spawn->timeout_warn_usec -= age_usec; + + r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC, + usec + spawn->timeout_warn_usec, USEC_PER_SEC, + on_spawn_timeout_warning, spawn); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to create timeout warning event source: %m"); + } + + spawn->timeout_usec -= age_usec; + + r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC, + usec + spawn->timeout_usec, USEC_PER_SEC, on_spawn_timeout, spawn); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to create timeout event source: %m"); + } + } + + if (spawn->fd_stdout >= 0) { + r = sd_event_add_io(e, &stdout_source, spawn->fd_stdout, EPOLLIN, on_spawn_io, spawn); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to create stdio event source: %m"); + r = sd_event_source_set_enabled(stdout_source, SD_EVENT_ONESHOT); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to enable stdio event source: %m"); + } + + if (spawn->fd_stderr >= 0) { + r = sd_event_add_io(e, &stderr_source, spawn->fd_stderr, EPOLLIN, on_spawn_io, spawn); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to create stderr event source: %m"); + r = sd_event_source_set_enabled(stderr_source, SD_EVENT_ONESHOT); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to enable stderr event source: %m"); + } + + r = sd_event_add_child(e, &sigchld_source, spawn->pid, WEXITED, on_spawn_sigchld, spawn); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to create sigchild event source: %m"); + /* SIGCHLD should be processed after IO is complete */ + r = sd_event_source_set_priority(sigchld_source, SD_EVENT_PRIORITY_NORMAL + 1); + if (r < 0) + return log_device_debug_errno(spawn->device, r, "Failed to set priority to sigchild event source: %m"); + + return sd_event_loop(e); +} + +int udev_event_spawn( + UdevEvent *event, + usec_t timeout_usec, + int timeout_signal, + bool accept_failure, + const char *cmd, + char *result, + size_t result_size, + bool *ret_truncated) { + + _cleanup_close_pair_ int outpipe[2] = EBADF_PAIR, errpipe[2] = EBADF_PAIR; + _cleanup_strv_free_ char **argv = NULL; + char **envp = NULL; + Spawn spawn; + pid_t pid; + int r; + + assert(event); + assert(event->dev); + assert(result || result_size == 0); + + /* pipes from child to parent */ + if (result || log_get_max_level() >= LOG_INFO) + if (pipe2(outpipe, O_NONBLOCK|O_CLOEXEC) != 0) + return log_device_error_errno(event->dev, errno, + "Failed to create pipe for command '%s': %m", cmd); + + if (log_get_max_level() >= LOG_INFO) + if (pipe2(errpipe, O_NONBLOCK|O_CLOEXEC) != 0) + return log_device_error_errno(event->dev, errno, + "Failed to create pipe for command '%s': %m", cmd); + + r = strv_split_full(&argv, cmd, NULL, EXTRACT_UNQUOTE | EXTRACT_RELAX | EXTRACT_RETAIN_ESCAPE); + if (r < 0) + return log_device_error_errno(event->dev, r, "Failed to split command: %m"); + + if (isempty(argv[0])) + return log_device_error_errno(event->dev, SYNTHETIC_ERRNO(EINVAL), + "Invalid command '%s'", cmd); + + /* allow programs in /usr/lib/udev/ to be called without the path */ + if (!path_is_absolute(argv[0])) { + char *program; + + program = path_join(UDEVLIBEXECDIR, argv[0]); + if (!program) + return log_oom(); + + free_and_replace(argv[0], program); + } + + r = device_get_properties_strv(event->dev, &envp); + if (r < 0) + return log_device_error_errno(event->dev, r, "Failed to get device properties"); + + log_device_debug(event->dev, "Starting '%s'", cmd); + + r = safe_fork_full("(spawn)", + (int[]) { -EBADF, outpipe[WRITE_END], errpipe[WRITE_END] }, + NULL, 0, + FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG_SIGTERM|FORK_REARRANGE_STDIO|FORK_LOG|FORK_RLIMIT_NOFILE_SAFE, + &pid); + if (r < 0) + return log_device_error_errno(event->dev, r, + "Failed to fork() to execute command '%s': %m", cmd); + if (r == 0) { + DEVICE_TRACE_POINT(spawn_exec, event->dev, cmd); + execve(argv[0], argv, envp); + _exit(EXIT_FAILURE); + } + + /* parent closed child's ends of pipes */ + outpipe[WRITE_END] = safe_close(outpipe[WRITE_END]); + errpipe[WRITE_END] = safe_close(errpipe[WRITE_END]); + + spawn = (Spawn) { + .device = event->dev, + .cmd = cmd, + .pid = pid, + .accept_failure = accept_failure, + .timeout_warn_usec = udev_warn_timeout(timeout_usec), + .timeout_usec = timeout_usec, + .timeout_signal = timeout_signal, + .event_birth_usec = event->birth_usec, + .fd_stdout = outpipe[READ_END], + .fd_stderr = errpipe[READ_END], + .result = result, + .result_size = result_size, + }; + r = spawn_wait(&spawn); + if (r < 0) + return log_device_error_errno(event->dev, r, + "Failed to wait for spawned command '%s': %m", cmd); + + if (result) + result[spawn.result_len] = '\0'; + + if (ret_truncated) + *ret_truncated = spawn.truncated; + + return r; /* 0 for success, and positive if the program failed */ +} + +void udev_event_execute_run(UdevEvent *event, usec_t timeout_usec, int timeout_signal) { + const char *command; + void *val; + int r; + + ORDERED_HASHMAP_FOREACH_KEY(val, command, event->run_list) { + UdevBuiltinCommand builtin_cmd = PTR_TO_UDEV_BUILTIN_CMD(val); + + if (builtin_cmd != _UDEV_BUILTIN_INVALID) { + log_device_debug(event->dev, "Running built-in command \"%s\"", command); + r = udev_builtin_run(event, builtin_cmd, command, false); + if (r < 0) + log_device_debug_errno(event->dev, r, "Failed to run built-in command \"%s\", ignoring: %m", command); + } else { + if (event->exec_delay_usec > 0) { + log_device_debug(event->dev, "Delaying execution of \"%s\" for %s.", + command, FORMAT_TIMESPAN(event->exec_delay_usec, USEC_PER_SEC)); + (void) usleep_safe(event->exec_delay_usec); + } + + log_device_debug(event->dev, "Running command \"%s\"", command); + + r = udev_event_spawn(event, timeout_usec, timeout_signal, false, command, NULL, 0, NULL); + if (r < 0) + log_device_warning_errno(event->dev, r, "Failed to execute '%s', ignoring: %m", command); + else if (r > 0) /* returned value is positive when program fails */ + log_device_debug(event->dev, "Command \"%s\" returned %d (error), ignoring.", command, r); + } + } +} |