From: Yu Watanabe Date: Tue, 23 Oct 2018 04:52:57 +0000 (+0900) Subject: udev-event: use sd_event_add_io() for reading stdout or stderr of spawned process X-Git-Tag: v240~483^2 X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fsystemd.git;a=commitdiff_plain;h=e81c3a4c5fbbea89fe6c1e3d0ace669b8130aa92 udev-event: use sd_event_add_io() for reading stdout or stderr of spawned process --- diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c index 29ccdd7145d..cdfda51f036 100644 --- a/src/udev/udev-event.c +++ b/src/udev/udev-event.c @@ -4,17 +4,13 @@ #include #include #include -#include #include #include #include -#include -#include -#include -#include -#include #include +#include "sd-event.h" + #include "alloc-util.h" #include "device-private.h" #include "fd-util.h" @@ -33,9 +29,15 @@ typedef struct Spawn { const char *cmd; pid_t pid; - usec_t timeout_warn; - usec_t timeout; + usec_t timeout_warn_usec; + usec_t timeout_usec; + usec_t event_birth_usec; bool accept_failure; + int fd_stdout; + int fd_stderr; + char *result; + size_t result_size; + size_t result_len; } Spawn; struct udev_event *udev_event_new(struct udev_device *dev) { @@ -406,130 +408,51 @@ out: return l; } -static void spawn_read(struct udev_event *event, - usec_t timeout_usec, - const char *cmd, - int fd_stdout, int fd_stderr, - char *result, size_t ressize) { - _cleanup_close_ int fd_ep = -1; - struct epoll_event ep_outpipe = { - .events = EPOLLIN, - .data.ptr = &fd_stdout, - }; - struct epoll_event ep_errpipe = { - .events = EPOLLIN, - .data.ptr = &fd_stderr, - }; - size_t respos = 0; - int r; +static int on_spawn_io(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + Spawn *spawn = userdata; + char buf[4096], *p; + size_t size; + ssize_t l; - /* read from child if requested */ - if (fd_stdout < 0 && fd_stderr < 0) - return; + assert(spawn); + assert(fd == spawn->fd_stdout || fd == spawn->fd_stderr); + assert(!spawn->result || spawn->result_len < spawn->result_size); - fd_ep = epoll_create1(EPOLL_CLOEXEC); - if (fd_ep < 0) { - log_error_errno(errno, "error creating epoll fd: %m"); - return; + 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); } - if (fd_stdout >= 0) { - r = epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stdout, &ep_outpipe); - if (r < 0) { - log_error_errno(errno, "fail to add stdout fd to epoll: %m"); - return; - } - } + l = read(fd, p, size - 1); + if (l < 0) { + if (errno != EAGAIN) + log_error_errno(errno, "Failed to read stdout of '%s': %m", spawn->cmd); - if (fd_stderr >= 0) { - r = epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stderr, &ep_errpipe); - if (r < 0) { - log_error_errno(errno, "fail to add stderr fd to epoll: %m"); - return; - } + return 0; } - /* read child output */ - while (fd_stdout >= 0 || fd_stderr >= 0) { - int timeout; - int fdcount; - struct epoll_event ev[4]; - int i; - - if (timeout_usec > 0) { - usec_t age_usec; - - age_usec = now(CLOCK_MONOTONIC) - event->birth_usec; - if (age_usec >= timeout_usec) { - log_error("timeout '%s'", cmd); - return; - } - timeout = ((timeout_usec - age_usec) / USEC_PER_MSEC) + MSEC_PER_SEC; - } else { - timeout = -1; - } - - fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), timeout); - if (fdcount < 0) { - if (errno == EINTR) - continue; - log_error_errno(errno, "failed to poll: %m"); - return; - } else if (fdcount == 0) { - log_error("timeout '%s'", cmd); - return; - } + p[l] = '\0'; + if (fd == spawn->fd_stdout && spawn->result) + spawn->result_len += l; - for (i = 0; i < fdcount; i++) { - int *fd = (int *)ev[i].data.ptr; - - if (*fd < 0) - continue; - - if (ev[i].events & EPOLLIN) { - ssize_t count; - char buf[4096]; - - count = read(*fd, buf, sizeof(buf)-1); - if (count <= 0) - continue; - buf[count] = '\0'; - - /* store stdout result */ - if (result != NULL && *fd == fd_stdout) { - if (respos + count < ressize) { - memcpy(&result[respos], buf, count); - respos += count; - } else { - log_error("'%s' ressize %zu too short", cmd, ressize); - } - } + /* Log output only if we watch stderr. */ + if (l > 0 && spawn->fd_stderr >= 0) { + _cleanup_strv_free_ char **v = NULL; + char **q; - /* log debug output only if we watch stderr */ - if (fd_stderr >= 0) { - char *pos; - char *line; + v = strv_split_newlines(p); + if (!v) + return 0; - pos = buf; - while ((line = strsep(&pos, "\n"))) { - if (pos != NULL || line[0] != '\0') - log_debug("'%s'(%s) '%s'", cmd, *fd == fd_stdout ? "out" : "err" , line); - } - } - } else if (ev[i].events & EPOLLHUP) { - r = epoll_ctl(fd_ep, EPOLL_CTL_DEL, *fd, NULL); - if (r < 0) { - log_error_errno(errno, "failed to remove fd from epoll: %m"); - return; - } - *fd = -1; - } - } + STRV_FOREACH(q, v) + log_debug("'%s'(%s) '%s'", spawn->cmd, + fd == spawn->fd_stdout ? "out" : "err", *q); } - /* return the child's stdout string */ - if (result != NULL) - result[respos] = '\0'; + return 0; } static int on_spawn_timeout(sd_event_source *s, uint64_t usec, void *userdata) { @@ -541,7 +464,7 @@ static int on_spawn_timeout(sd_event_source *s, uint64_t usec, void *userdata) { kill_and_sigcont(spawn->pid, SIGKILL); log_error("Spawned process '%s' ["PID_FMT"] timed out after %s, killing", spawn->cmd, spawn->pid, - format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout)); + format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout_usec)); return 1; } @@ -553,7 +476,7 @@ static int on_spawn_timeout_warning(sd_event_source *s, uint64_t usec, void *use assert(spawn); log_warning("Spawned process '%s' ["PID_FMT"] is taking longer than %s to complete", spawn->cmd, spawn->pid, - format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout)); + format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout_warn_usec)); return 1; } @@ -589,49 +512,52 @@ static int on_spawn_sigchld(sd_event_source *s, const siginfo_t *si, void *userd return 1; } -static int spawn_wait(struct udev_event *event, - usec_t timeout_usec, - usec_t timeout_warn_usec, - const char *cmd, pid_t pid, - bool accept_failure) { - Spawn spawn = { - .cmd = cmd, - .pid = pid, - .accept_failure = accept_failure, - }; +static int spawn_wait(Spawn *spawn) { _cleanup_(sd_event_unrefp) sd_event *e = NULL; int r, ret; + assert(spawn); + r = sd_event_new(&e); if (r < 0) return r; - if (timeout_usec > 0) { + if (spawn->timeout_usec > 0) { usec_t usec, age_usec; usec = now(CLOCK_MONOTONIC); - age_usec = usec - event->birth_usec; - if (age_usec < timeout_usec) { - if (timeout_warn_usec > 0 && timeout_warn_usec < timeout_usec && age_usec < timeout_warn_usec) { - spawn.timeout_warn = timeout_warn_usec - age_usec; + 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_PER_SEC, - on_spawn_timeout_warning, &spawn); + usec + spawn->timeout_warn_usec, USEC_PER_SEC, + on_spawn_timeout_warning, spawn); if (r < 0) return r; } - spawn.timeout = timeout_usec - age_usec; + spawn->timeout_usec -= age_usec; r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC, - usec + spawn.timeout, USEC_PER_SEC, on_spawn_timeout, &spawn); + usec + spawn->timeout_usec, USEC_PER_SEC, on_spawn_timeout, spawn); if (r < 0) return r; } } - r = sd_event_add_child(e, NULL, pid, WEXITED, on_spawn_sigchld, &spawn); + r = sd_event_add_io(e, NULL, spawn->fd_stdout, EPOLLIN, on_spawn_io, spawn); + if (r < 0) + return r; + + r = sd_event_add_io(e, NULL, spawn->fd_stderr, EPOLLIN, on_spawn_io, spawn); + if (r < 0) + return r; + + r = sd_event_add_child(e, NULL, spawn->pid, WEXITED, on_spawn_sigchld, spawn); if (r < 0) return r; @@ -655,9 +581,12 @@ int udev_event_spawn(struct udev_event *event, _cleanup_close_pair_ int outpipe[2] = {-1, -1}, errpipe[2] = {-1, -1}; _cleanup_strv_free_ char **argv = NULL; char **envp = NULL; + Spawn spawn; pid_t pid; int r; + assert(result || ressize == 0); + /* pipes from child to parent */ if (result || log_get_max_level() >= LOG_INFO) if (pipe2(outpipe, O_NONBLOCK|O_CLOEXEC) != 0) @@ -705,16 +634,25 @@ int udev_event_spawn(struct udev_event *event, 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); - - r = spawn_wait(event, timeout_usec, timeout_warn_usec, cmd, pid, accept_failure); + spawn = (Spawn) { + .cmd = cmd, + .pid = pid, + .accept_failure = accept_failure, + .timeout_warn_usec = timeout_warn_usec, + .timeout_usec = timeout_usec, + .event_birth_usec = event->birth_usec, + .fd_stdout = outpipe[READ_END], + .fd_stderr = errpipe[READ_END], + .result = result, + .result_size = ressize, + }; + r = spawn_wait(&spawn); if (r < 0) return log_error_errno(r, "Failed to wait spawned command '%s': %m", cmd); + if (result) + result[spawn.result_len] = '\0'; + return r; }