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-rw-r--r--src/shared/exec-util.c446
1 files changed, 446 insertions, 0 deletions
diff --git a/src/shared/exec-util.c b/src/shared/exec-util.c
new file mode 100644
index 0000000..61ee3b1
--- /dev/null
+++ b/src/shared/exec-util.c
@@ -0,0 +1,446 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#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-file.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 "rlimit-util.h"
+#include "serialize.h"
+#include "set.h"
+#include "signal-util.h"
+#include "stat-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "tmpfile-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;
+ int r;
+
+ if (null_or_empty_path(path)) {
+ log_debug("%s is empty (a mask).", path);
+ return 0;
+ }
+
+ r = safe_fork("(direxec)", FORK_DEATHSIG|FORK_LOG, &_pid);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ char *_argv[2];
+
+ if (stdout_fd >= 0) {
+ r = rearrange_stdio(STDIN_FILENO, stdout_fd, STDERR_FILENO);
+ if (r < 0)
+ _exit(EXIT_FAILURE);
+ }
+
+ (void) rlimit_nofile_safe();
+
+ 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);
+ }
+
+ *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[],
+ char *envp[],
+ ExecDirFlags flags) {
+
+ _cleanup_hashmap_free_free_ Hashmap *pids = NULL;
+ _cleanup_strv_free_ char **paths = NULL;
+ char **path, **e;
+ int r;
+ bool parallel_execution;
+
+ /* We fork this all off from a child process so that we can somewhat cleanly make
+ * use of SIGALRM to set a time limit.
+ *
+ * We attempt to perform parallel execution if configured by the user, however
+ * if `callbacks` is nonnull, execution must be serial.
+ */
+ parallel_execution = FLAGS_SET(flags, EXEC_DIR_PARALLEL) && !callbacks;
+
+ r = conf_files_list_strv(&paths, NULL, NULL, CONF_FILES_EXECUTABLE|CONF_FILES_REGULAR|CONF_FILES_FILTER_MASKED, (const char* const*) directories);
+ if (r < 0)
+ return log_error_errno(r, "Failed to enumerate executables: %m");
+
+ if (parallel_execution) {
+ pids = hashmap_new(NULL);
+ if (!pids)
+ return log_oom();
+ }
+
+ /* Abort execution of this process after the timeout. We simply rely on SIGALRM as
+ * default action terminating the process, and turn on alarm(). */
+
+ if (timeout != USEC_INFINITY)
+ alarm(DIV_ROUND_UP(timeout, USEC_PER_SEC));
+
+ STRV_FOREACH(e, envp)
+ if (putenv(*e) != 0)
+ return log_error_errno(errno, "Failed to set environment variable: %m");
+
+ 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 (parallel_execution) {
+ r = hashmap_put(pids, PID_TO_PTR(pid), t);
+ if (r < 0)
+ return log_oom();
+ t = NULL;
+ } else {
+ r = wait_for_terminate_and_check(t, pid, WAIT_LOG);
+ if (FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS)) {
+ if (r < 0)
+ continue;
+ } else if (r > 0)
+ return r;
+
+ if (callbacks) {
+ 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);
+
+ r = wait_for_terminate_and_check(t, pid, WAIT_LOG);
+ if (!FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS) && r > 0)
+ return r;
+ }
+
+ 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[],
+ char *envp[],
+ ExecDirFlags flags) {
+
+ char **dirs = (char**) directories;
+ _cleanup_close_ int fd = -1;
+ char *name;
+ int r;
+ pid_t executor_pid;
+
+ 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. */
+
+ r = safe_fork("(sd-executor)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &executor_pid);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ r = do_execute(dirs, timeout, callbacks, callback_args, fd, argv, envp, flags);
+ _exit(r < 0 ? EXIT_FAILURE : r);
+ }
+
+ r = wait_for_terminate_and_check("(sd-executor)", executor_pid, 0);
+ if (r < 0)
+ return r;
+ if (!FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS) && r > 0)
+ return r;
+
+ 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 = NULL;
+ 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, &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) {
+ _cleanup_fclose_ FILE *f = NULL;
+ char ***env = arg;
+ 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_strv(f, "env", *env);
+ if (r < 0)
+ return r;
+
+ r = fflush_and_check(f);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int gather_environment_consume(int fd, void *arg) {
+ _cleanup_fclose_ FILE *f = NULL;
+ char ***env = arg;
+ int r = 0;
+
+ /* 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;
+ }
+
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+ const char *v;
+ int k;
+
+ k = read_line(f, LONG_LINE_MAX, &line);
+ if (k < 0)
+ return k;
+ if (k == 0)
+ break;
+
+ v = startswith(line, "env=");
+ if (!v) {
+ log_debug("Serialization line \"%s\" unexpectedly didn't start with \"env=\".", line);
+ if (r == 0)
+ r = -EINVAL;
+
+ continue;
+ }
+
+ k = deserialize_environment(v, env);
+ if (k < 0) {
+ log_debug_errno(k, "Invalid serialization line \"%s\": %m", line);
+
+ if (r == 0)
+ r = k;
+ }
+ }
+
+ return r;
+}
+
+int exec_command_flags_from_strv(char **ex_opts, ExecCommandFlags *flags) {
+ ExecCommandFlags ex_flag, ret_flags = 0;
+ char **opt;
+
+ assert(flags);
+
+ STRV_FOREACH(opt, ex_opts) {
+ ex_flag = exec_command_flags_from_string(*opt);
+ if (ex_flag >= 0)
+ ret_flags |= ex_flag;
+ else
+ return -EINVAL;
+ }
+
+ *flags = ret_flags;
+
+ return 0;
+}
+
+int exec_command_flags_to_strv(ExecCommandFlags flags, char ***ex_opts) {
+ _cleanup_strv_free_ char **ret_opts = NULL;
+ ExecCommandFlags it = flags;
+ const char *str;
+ int i, r;
+
+ assert(ex_opts);
+
+ for (i = 0; it != 0; it &= ~(1 << i), i++) {
+ if (FLAGS_SET(flags, (1 << i))) {
+ str = exec_command_flags_to_string(1 << i);
+ if (!str)
+ return -EINVAL;
+
+ r = strv_extend(&ret_opts, str);
+ if (r < 0)
+ return r;
+ }
+ }
+
+ *ex_opts = TAKE_PTR(ret_opts);
+
+ return 0;
+}
+
+const gather_stdout_callback_t gather_environment[] = {
+ gather_environment_generate,
+ gather_environment_collect,
+ gather_environment_consume,
+};
+
+static const char* const exec_command_strings[] = {
+ "ignore-failure", /* EXEC_COMMAND_IGNORE_FAILURE */
+ "privileged", /* EXEC_COMMAND_FULLY_PRIVILEGED */
+ "no-setuid", /* EXEC_COMMAND_NO_SETUID */
+ "ambient", /* EXEC_COMMAND_AMBIENT_MAGIC */
+ "no-env-expand", /* EXEC_COMMAND_NO_ENV_EXPAND */
+};
+
+const char* exec_command_flags_to_string(ExecCommandFlags i) {
+ size_t idx;
+
+ for (idx = 0; idx < ELEMENTSOF(exec_command_strings); idx++)
+ if (i == (1 << idx))
+ return exec_command_strings[idx];
+
+ return NULL;
+}
+
+ExecCommandFlags exec_command_flags_from_string(const char *s) {
+ ssize_t idx;
+
+ idx = string_table_lookup(exec_command_strings, ELEMENTSOF(exec_command_strings), s);
+
+ if (idx < 0)
+ return _EXEC_COMMAND_FLAGS_INVALID;
+ else
+ return 1 << idx;
+}
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