diff options
Diffstat (limited to 'src/basic/exec-util.c')
| -rw-r--r-- | src/basic/exec-util.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/src/basic/exec-util.c b/src/basic/exec-util.c new file mode 100644 index 0000000000..aced9e8e3d --- /dev/null +++ b/src/basic/exec-util.c @@ -0,0 +1,360 @@ +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <dirent.h> +#include <errno.h> +#include <sys/prctl.h> +#include <sys/types.h> +#include <unistd.h> +#include <stdio.h> + +#include "alloc-util.h" +#include "conf-files.h" +#include "env-util.h" +#include "exec-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "hashmap.h" +#include "macro.h" +#include "process-util.h" +#include "set.h" +#include "signal-util.h" +#include "stat-util.h" +#include "string-util.h" +#include "strv.h" +#include "terminal-util.h" +#include "util.h" + +/* Put this test here for a lack of better place */ +assert_cc(EAGAIN == EWOULDBLOCK); + +static int do_spawn(const char *path, char *argv[], int stdout_fd, pid_t *pid) { + + pid_t _pid; + + 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) { + 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 && + dup2(stdout_fd, STDOUT_FILENO) < 0) + return -errno; + + fd_cloexec(STDOUT_FILENO, false); + } + + if (!argv) { + _argv[0] = (char*) path; + _argv[1] = NULL; + argv = _argv; + } else + argv[0] = (char*) path; + + execv(path, argv); + log_error_errno(errno, "Failed to execute %s: %m", path); + _exit(EXIT_FAILURE); + } + + log_debug("Spawned %s as " PID_FMT ".", path, _pid); + *pid = _pid; + return 1; +} + +static int do_execute( + char **directories, + usec_t timeout, + gather_stdout_callback_t const callbacks[_STDOUT_CONSUME_MAX], + void* const callback_args[_STDOUT_CONSUME_MAX], + int output_fd, + char *argv[]) { + + _cleanup_hashmap_free_free_ Hashmap *pids = NULL; + _cleanup_strv_free_ char **paths = NULL; + char **path; + int r; + + /* We fork this all off from a child process so that we can somewhat cleanly make + * use of SIGALRM to set a time limit. + * + * 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, (const char* const*) directories); + if (r < 0) + return r; + + if (!callbacks) { + pids = hashmap_new(NULL); + if (!pids) + return log_oom(); + } + + /* Abort execution of this process after the timout. We simply rely on SIGALRM as + * default action terminating the process, and turn on alarm(). */ + + if (timeout != USEC_INFINITY) + alarm((timeout + USEC_PER_SEC - 1) / USEC_PER_SEC); + + STRV_FOREACH(path, paths) { + _cleanup_free_ char *t = NULL; + _cleanup_close_ int fd = -1; + pid_t pid; + + t = strdup(*path); + if (!t) + return log_oom(); + + if (callbacks) { + fd = open_serialization_fd(basename(*path)); + if (fd < 0) + return log_error_errno(fd, "Failed to open serialization file: %m"); + } + + r = do_spawn(t, argv, fd, &pid); + if (r <= 0) + continue; + + if (pids) { + r = hashmap_put(pids, PID_TO_PTR(pid), t); + if (r < 0) + return log_oom(); + t = NULL; + } else { + r = wait_for_terminate_and_warn(t, pid, true); + if (r < 0) + continue; + + if (lseek(fd, 0, SEEK_SET) < 0) + return log_error_errno(errno, "Failed to seek on serialization fd: %m"); + + r = callbacks[STDOUT_GENERATE](fd, callback_args[STDOUT_GENERATE]); + fd = -1; + if (r < 0) + return log_error_errno(r, "Failed to process output from %s: %m", *path); + } + } + + if (callbacks) { + r = callbacks[STDOUT_COLLECT](output_fd, callback_args[STDOUT_COLLECT]); + if (r < 0) + return log_error_errno(r, "Callback two failed: %m"); + } + + while (!hashmap_isempty(pids)) { + _cleanup_free_ char *t = NULL; + pid_t pid; + + pid = PTR_TO_PID(hashmap_first_key(pids)); + assert(pid > 0); + + t = hashmap_remove(pids, PID_TO_PTR(pid)); + assert(t); + + wait_for_terminate_and_warn(t, pid, true); + } + + return 0; +} + +int execute_directories( + const char* const* directories, + usec_t timeout, + gather_stdout_callback_t const callbacks[_STDOUT_CONSUME_MAX], + void* const callback_args[_STDOUT_CONSUME_MAX], + char *argv[]) { + + pid_t executor_pid; + char *name; + char **dirs = (char**) directories; + _cleanup_close_ int fd = -1; + int r; + + assert(!strv_isempty(dirs)); + + name = basename(dirs[0]); + assert(!isempty(name)); + + if (callbacks) { + assert(callback_args); + assert(callbacks[STDOUT_GENERATE]); + assert(callbacks[STDOUT_COLLECT]); + assert(callbacks[STDOUT_CONSUME]); + + fd = open_serialization_fd(name); + if (fd < 0) + return log_error_errno(fd, "Failed to open serialization file: %m"); + } + + /* Executes all binaries in the directories serially or in parallel and waits for + * 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 = do_execute(dirs, timeout, callbacks, callback_args, fd, argv); + _exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS); + } + + r = wait_for_terminate_and_warn(name, executor_pid, true); + if (r < 0) + return log_error_errno(r, "Execution failed: %m"); + if (r > 0) { + /* non-zero return code from child */ + log_error("Forker process failed."); + return -EREMOTEIO; + } + + if (!callbacks) + return 0; + + if (lseek(fd, 0, SEEK_SET) < 0) + return log_error_errno(errno, "Failed to rewind serialization fd: %m"); + + r = callbacks[STDOUT_CONSUME](fd, callback_args[STDOUT_CONSUME]); + fd = -1; + if (r < 0) + return log_error_errno(r, "Failed to parse returned data: %m"); + return 0; +} + +static int gather_environment_generate(int fd, void *arg) { + char ***env = arg, **x, **y; + _cleanup_fclose_ FILE *f = NULL; + _cleanup_strv_free_ char **new; + int r; + + /* Read a series of VAR=value assignments from fd, use them to update the list of + * variables in env. Also update the exported environment. + * + * fd is always consumed, even on error. + */ + + assert(env); + + f = fdopen(fd, "r"); + if (!f) { + safe_close(fd); + return -errno; + } + + r = load_env_file_pairs(f, NULL, NULL, &new); + if (r < 0) + return r; + + STRV_FOREACH_PAIR(x, y, new) { + char *p; + + if (!env_name_is_valid(*x)) { + log_warning("Invalid variable assignment \"%s=...\", ignoring.", *x); + continue; + } + + p = strjoin(*x, "=", *y); + if (!p) + return -ENOMEM; + + r = strv_env_replace(env, p); + if (r < 0) + return r; + + if (setenv(*x, *y, true) < 0) + return -errno; + } + + return r; +} + +static int gather_environment_collect(int fd, void *arg) { + char ***env = arg; + _cleanup_fclose_ FILE *f = NULL; + int r; + + /* Write out a series of env=cescape(VAR=value) assignments to fd. */ + + assert(env); + + f = fdopen(fd, "w"); + if (!f) { + safe_close(fd); + return -errno; + } + + r = serialize_environment(f, *env); + if (r < 0) + return r; + + if (ferror(f)) + return errno > 0 ? -errno : -EIO; + + return 0; +} + +static int gather_environment_consume(int fd, void *arg) { + char ***env = arg; + _cleanup_fclose_ FILE *f = NULL; + char line[LINE_MAX]; + int r = 0, k; + + /* Read a series of env=cescape(VAR=value) assignments from fd into env. */ + + assert(env); + + f = fdopen(fd, "r"); + if (!f) { + safe_close(fd); + return -errno; + } + + FOREACH_LINE(line, f, return -EIO) { + truncate_nl(line); + + k = deserialize_environment(env, line); + if (k < 0) + log_error_errno(k, "Invalid line \"%s\": %m", line); + if (k < 0 && r == 0) + r = k; + } + + return r; +} + +const gather_stdout_callback_t gather_environment[] = { + gather_environment_generate, + gather_environment_collect, + gather_environment_consume, +}; |