15057632786

Committed 15 May 2025 09:01PM UTC coverage: 72.267% (+0.02%) from 72.244%

Build # 15057632786

Build Type

push

github

Committed by

bluca

Commit Message

man: document how to hook stuff into system wakeup

Fixes: #6364

Coverage Stats

298523 of 413084 relevant lines covered (72.27%)

738132.88 hits per line

Source File
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75.9

/src/shared/exec-util.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <unistd.h>

#include "alloc-util.h"
#include "bitfield.h"
#include "conf-files.h"
#include "env-file.h"
#include "env-util.h"
#include "errno-util.h"
#include "escape.h"
#include "exec-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "hashmap.h"
#include "macro.h"
#include "missing_syscall.h"
#include "path-util.h"
#include "process-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"

#define EXIT_SKIP_REMAINING 77

/* 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,
                bool set_systemd_exec_pid,
                pid_t *ret_pid) {

        int r;

        assert(path);
        assert(ret_pid);

        if (null_or_empty_path(path) > 0) {
                log_debug("%s is masked, skipping.", path);
                return 0;
        }

        pid_t pid;
        r = safe_fork_full(
                        "(exec-inner)",
                        (const int[]) { STDIN_FILENO, stdout_fd < 0 ? STDOUT_FILENO : stdout_fd, STDERR_FILENO },
                        /* except_fds= */ NULL, /* n_except_fds= */ 0,
                        FORK_DEATHSIG_SIGTERM|FORK_LOG|FORK_RLIMIT_NOFILE_SAFE|FORK_REARRANGE_STDIO|FORK_CLOSE_ALL_FDS,
                        &pid);
        if (r < 0)
                return r;
        if (r == 0) {
                char *_argv[2];

                if (set_systemd_exec_pid) {
                        r = setenv_systemd_exec_pid(false);
                        if (r < 0)
                                log_warning_errno(r, "Failed to set $SYSTEMD_EXEC_PID, ignoring: %m");
                }

                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);
        }

        *ret_pid = pid;
        return 1;
}

static int do_execute(
                char * const *paths,
                const char *root,
                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_ Hashmap *pids = NULL;
        bool parallel_execution;
        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.
         *
         * We attempt to perform parallel execution if configured by the user, however if `callbacks` is nonnull,
         * execution must be serial.
         */

        assert(!strv_isempty(paths));

        parallel_execution = FLAGS_SET(flags, EXEC_DIR_PARALLEL) && !callbacks;

        /* 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 = -EBADF;
                pid_t pid;

                t = path_join(root, *path);
                if (!t)
                        return log_oom();

                if (callbacks) {
                        _cleanup_free_ char *bn = NULL;

                        r = path_extract_filename(*path, &bn);
                        if (r < 0)
                                return log_error_errno(r, "Failed to extract filename from path '%s': %m", *path);

                        fd = open_serialization_fd(bn);
                        if (fd < 0)
                                return log_error_errno(fd, "Failed to open serialization file: %m");
                }

                if (DEBUG_LOGGING) {
                        _cleanup_free_ char *s = NULL;

                        char **args = strv_skip(argv, 1);
                        if (args)
                                s = quote_command_line(args, SHELL_ESCAPE_EMPTY);

                        log_debug("About to execute %s%s%s", t, args ? " " : "", args ? strnull(s) : "");
                }

                if (FLAGS_SET(flags, EXEC_DIR_WARN_WORLD_WRITABLE)) {
                        struct stat st;

                        r = stat(t, &st);
                        if (r < 0)
                                log_warning_errno(errno, "Failed to stat '%s', ignoring: %m", t);
                        else if (S_ISREG(st.st_mode) && (st.st_mode & 0002))
                                log_warning("'%s' is marked world-writable, which is a security risk as it "
                                            "is executed with privileges. Please remove world writability "
                                            "permission bits. Proceeding anyway.", t);
                }

                r = do_spawn(t, argv, fd, FLAGS_SET(flags, EXEC_DIR_SET_SYSTEMD_EXEC_PID), &pid);
                if (r <= 0)
                        continue;

                if (parallel_execution) {
                        r = hashmap_ensure_put(&pids, &trivial_hash_ops_value_free, PID_TO_PTR(pid), t);
                        if (r < 0)
                                return log_oom();
                        t = NULL;
                } else {
                        bool skip_remaining = false;

                        r = wait_for_terminate_and_check(t, pid, WAIT_LOG_ABNORMAL);
                        if (r < 0)
                                return r;
                        if (r > 0) {
                                if (FLAGS_SET(flags, EXEC_DIR_SKIP_REMAINING) && r == EXIT_SKIP_REMAINING) {
                                        log_info("%s succeeded with exit status %i, not executing remaining executables.", *path, r);
                                        skip_remaining = true;
                                } else if (FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS))
                                        log_warning("%s failed with exit status %i, ignoring.", *path, r);
                                else {
                                        log_error("%s failed with exit status %i.", *path, r);
                                        return r;
                                }
                        }

                        if (callbacks) {
                                r = finish_serialization_fd(fd);
                                if (r < 0)
                                        return log_error_errno(r, "Failed to finish serialization fd: %m");

                                r = callbacks[STDOUT_GENERATE](TAKE_FD(fd), callback_args[STDOUT_GENERATE]);
                                if (r < 0)
                                        return log_error_errno(r, "Failed to process output from %s: %m", *path);
                        }

                        if (skip_remaining)
                                break;
                }
        }

        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;
                void *p;

                t = ASSERT_PTR(hashmap_steal_first_key_and_value(pids, &p));
                pid = PTR_TO_PID(p);
                assert(pid > 0);

                r = wait_for_terminate_and_check(t, pid, WAIT_LOG);
                if (r < 0)
                        return r;
                if (!FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS) && r > 0)
                        return r;
        }

        return 0;
}

int execute_strv(
                const char *name,
                char * const *paths,
                const char *root,
                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) {

        _cleanup_close_ int fd = -EBADF;
        pid_t executor_pid;
        int r;

        assert(!FLAGS_SET(flags, EXEC_DIR_PARALLEL | EXEC_DIR_SKIP_REMAINING));

        if (strv_isempty(paths))
                return 0;

        if (callbacks) {
                assert(name);
                assert(callbacks[STDOUT_GENERATE]);
                assert(callbacks[STDOUT_COLLECT]);
                assert(callbacks[STDOUT_CONSUME]);
                assert(callback_args);

                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-exec-strv)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGTERM|FORK_LOG, &executor_pid);
        if (r < 0)
                return r;
        if (r == 0) {
                r = do_execute(paths, root, timeout, callbacks, callback_args, fd, argv, envp, flags);
                _exit(r < 0 ? EXIT_FAILURE : r);
        }

        r = wait_for_terminate_and_check("(sd-exec-strv)", executor_pid, 0);
        if (r < 0)
                return r;
        if (!FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS) && r > 0)
                return r;

        if (!callbacks)
                return 0;

        r = finish_serialization_fd(fd);
        if (r < 0)
                return log_error_errno(r, "Failed to finish serialization fd: %m");

        r = callbacks[STDOUT_CONSUME](TAKE_FD(fd), callback_args[STDOUT_CONSUME]);
        if (r < 0)
                return log_error_errno(r, "Failed to parse returned data: %m");

        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) {

        _cleanup_strv_free_ char **paths = NULL;
        _cleanup_free_ char *name = NULL;
        int r;

        assert(!strv_isempty((char* const*) directories));

        r = conf_files_list_strv(&paths, NULL, NULL, CONF_FILES_EXECUTABLE|CONF_FILES_REGULAR|CONF_FILES_FILTER_MASKED, directories);
        if (r < 0)
                return log_error_errno(r, "Failed to enumerate executables: %m");

        if (strv_isempty(paths)) {
                log_debug("No executables found.");
                return 0;
        }

        if (callbacks) {
                r = path_extract_filename(directories[0], &name);
                if (r < 0)
                        return log_error_errno(r, "Failed to extract file name from '%s': %m", directories[0]);
        }

        return execute_strv(name, paths, /* root = */ NULL, timeout, callbacks, callback_args, argv, envp, flags);
}

static int gather_environment_generate(int fd, void *arg) {
        char ***env = ASSERT_PTR(arg);
        _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(fd >= 0);

        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) {
                if (!env_name_is_valid(*x)) {
                        log_warning("Invalid variable assignment \"%s=...\", ignoring.", *x);
                        continue;
                }

                r = strv_env_assign(env, *x, *y);
                if (r < 0)
                        return r;

                if (setenv(*x, *y, /* overwrite = */ true) < 0)
                        return -errno;
        }

        return 0;
}

static int gather_environment_collect(int fd, void *arg) {
        char ***env = ASSERT_PTR(arg);
        _cleanup_fclose_ FILE *f = NULL;
        int r;

        /* Write out a series of env=cescape(VAR=value) assignments to fd. */

        assert(fd >= 0);

        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) {
        char ***env = ASSERT_PTR(arg);
        _cleanup_fclose_ FILE *f = NULL;
        int r, ret = 0;

        /* Read a series of env=cescape(VAR=value) assignments from fd into env. */

        assert(fd >= 0);

        f = fdopen(fd, "r");
        if (!f) {
                safe_close(fd);
                return -errno;
        }

        for (;;) {
                _cleanup_free_ char *line = NULL;
                const char *v;

                r = read_line(f, LONG_LINE_MAX, &line);
                if (r < 0)
                        return r;
                if (r == 0)
                        return ret;

                v = startswith(line, "env=");
                if (!v) {
                        RET_GATHER(ret, log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
                                                        "Serialization line unexpectedly didn't start with \"env=\", ignoring: %s",
                                                        line));
                        continue;
                }

                r = deserialize_environment(v, env);
                if (r < 0)
                        RET_GATHER(ret, log_debug_errno(r, "Failed to deserialize line \"%s\": %m", line));
        }
}

const gather_stdout_callback_t gather_environment[_STDOUT_CONSUME_MAX] = {
        gather_environment_generate,
        gather_environment_collect,
        gather_environment_consume,
};

int exec_command_flags_from_strv(char * const *ex_opts, ExecCommandFlags *ret) {
        ExecCommandFlags flags = 0;

        assert(ret);

        STRV_FOREACH(opt, ex_opts) {
                ExecCommandFlags fl = exec_command_flags_from_string(*opt);
                if (fl < 0)
                        return fl;

                flags |= fl;
        }

        *ret = flags;

        return 0;
}

int exec_command_flags_to_strv(ExecCommandFlags flags, char ***ret) {
        _cleanup_strv_free_ char **opts = NULL;
        int r;

        assert(flags >= 0);
        assert(ret);

        BIT_FOREACH(i, flags) {
                const char *s = exec_command_flags_to_string(1 << i);
                if (!s)
                        return -EINVAL;

                r = strv_extend(&opts, s);
                if (r < 0)
                        return r;
        }

        *ret = TAKE_PTR(opts);

        return 0;
}

static const char* const exec_command_strings[] = {
        "ignore-failure", /* EXEC_COMMAND_IGNORE_FAILURE */
        "privileged",     /* EXEC_COMMAND_FULLY_PRIVILEGED */
        "no-setuid",      /* EXEC_COMMAND_NO_SETUID */
        "no-env-expand",  /* EXEC_COMMAND_NO_ENV_EXPAND */
        "via-shell",      /* EXEC_COMMAND_VIA_SHELL */
};

assert_cc((1 << ELEMENTSOF(exec_command_strings)) - 1 == _EXEC_COMMAND_FLAGS_ALL);

const char* exec_command_flags_to_string(ExecCommandFlags i) {
        for (size_t 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;

        if (streq(s, "ambient")) /* Compatibility with ambient hack, removed in v258, map to no bits set */
                return 0;

        idx = string_table_lookup_from_string(exec_command_strings, ELEMENTSOF(exec_command_strings), s);
        if (idx < 0)
                return _EXEC_COMMAND_FLAGS_INVALID;

        return 1 << idx;
}

int fexecve_or_execve(int executable_fd, const char *executable, char *const argv[], char *const envp[]) {
        /* Refuse invalid fds, regardless if fexecve() use is enabled or not */
        if (executable_fd < 0)
                return -EBADF;

        /* Block any attempts on exploiting Linux' liberal argv[] handling, i.e. CVE-2021-4034 and suchlike */
        if (isempty(executable) || strv_isempty(argv))
                return -EINVAL;

#if ENABLE_FEXECVE

        execveat(executable_fd, "", argv, envp, AT_EMPTY_PATH);

        if (IN_SET(errno, ENOSYS, ENOENT) || ERRNO_IS_PRIVILEGE(errno))
                /* Old kernel or a script or an overzealous seccomp filter? Let's fall back to execve().
                 *
                 * fexecve(3): "If fd refers to a script (i.e., it is an executable text file that names a
                 * script interpreter with a first line that begins with the characters #!) and the
                 * close-on-exec flag has been set for fd, then fexecve() fails with the error ENOENT. This
                 * error occurs because, by the time the script interpreter is executed, fd has already been
                 * closed because of the close-on-exec flag. Thus, the close-on-exec flag can't be set on fd
                 * if it refers to a script."
                 *
                 * Unfortunately, if we unset close-on-exec, the script will be executed just fine, but (at
                 * least in case of bash) the script name, $0, will be shown as /dev/fd/nnn, which breaks
                 * scripts which make use of $0. Thus, let's fall back to execve() in this case.
                 */
#endif
                execve(executable, argv, envp);
        return -errno;
}

int shall_fork_agent(void) {
        int r;

        /* Check if we have a controlling terminal. If not (ENXIO here), we aren't actually invoked
         * interactively on a terminal, hence fail. */
        r = get_ctty_devnr(0, NULL);
        if (r == -ENXIO)
                return false;
        if (r < 0)
                return r;

        if (!is_main_thread())
                return -EPERM;

        return true;
}

int _fork_agent(const char *name, char * const *argv, const int except[], size_t n_except, pid_t *ret_pid) {
        int r;

        assert(!strv_isempty(argv));

        /* Spawns a temporary TTY agent, making sure it goes away when we go away */

        r = safe_fork_full(name,
                           NULL,
                           (int*) except, /* safe_fork_full only changes except if you pass in FORK_PACK_FDS, which we don't */
                           n_except,
                           FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGTERM|FORK_CLOSE_ALL_FDS|FORK_REOPEN_LOG|FORK_RLIMIT_NOFILE_SAFE,
                           ret_pid);
        if (r < 0)
                return r;
        if (r > 0)
                return 0;

        /* In the child: */

        bool stdin_is_tty = isatty_safe(STDIN_FILENO),
                stdout_is_tty = isatty_safe(STDOUT_FILENO),
                stderr_is_tty = isatty_safe(STDERR_FILENO);

        if (!stdin_is_tty || !stdout_is_tty || !stderr_is_tty) {
                int fd;

                /* Detach from stdin/stdout/stderr and reopen /dev/tty for them. This is important to ensure
                 * that when systemctl is started via popen() or a similar call that expects to read EOF we
                 * actually do generate EOF and not delay this indefinitely by keeping an unused copy of
                 * stdin around. */
                fd = open_terminal("/dev/tty", stdin_is_tty ? O_WRONLY : (stdout_is_tty && stderr_is_tty) ? O_RDONLY : O_RDWR);
                if (fd < 0) {
                        log_error_errno(fd, "Failed to open /dev/tty: %m");
                        _exit(EXIT_FAILURE);
                }

                if (!stdin_is_tty && dup2(fd, STDIN_FILENO) < 0) {
                        log_error_errno(errno, "Failed to dup2 /dev/tty to STDIN: %m");
                        _exit(EXIT_FAILURE);
                }

                if (!stdout_is_tty && dup2(fd, STDOUT_FILENO) < 0) {
                        log_error_errno(errno, "Failed to dup2 /dev/tty to STDOUT: %m");
                        _exit(EXIT_FAILURE);
                }

                if (!stderr_is_tty && dup2(fd, STDERR_FILENO) < 0) {
                        log_error_errno(errno, "Failed to dup2 /dev/tty to STDERR: %m");
                        _exit(EXIT_FAILURE);
                }

                fd = safe_close_above_stdio(fd);
        }

        /* Count arguments */
        execv(argv[0], argv);

        /* Let's treat missing agent binary as a graceful issue (in order to support splitting out the Polkit
         * or password agents into separate, optional distro packages), and not complain loudly. */
        log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno,
                       "Failed to execute %s: %m", argv[0]);
        _exit(EXIT_FAILURE);
}

1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3	#include <dirent.h>
4	#include <errno.h>
5	#include <stdio.h>
6	#include <sys/prctl.h>
7	#include <sys/types.h>
8	#include <unistd.h>
9
10	#include "alloc-util.h"
11	#include "bitfield.h"
12	#include "conf-files.h"
13	#include "env-file.h"
14	#include "env-util.h"
15	#include "errno-util.h"
16	#include "escape.h"
17	#include "exec-util.h"
18	#include "fd-util.h"
19	#include "fileio.h"
20	#include "hashmap.h"
21	#include "macro.h"
22	#include "missing_syscall.h"
23	#include "path-util.h"
24	#include "process-util.h"
25	#include "serialize.h"
26	#include "set.h"
27	#include "signal-util.h"
28	#include "stat-util.h"
29	#include "string-table.h"
30	#include "string-util.h"
31	#include "strv.h"
32	#include "terminal-util.h"
33
34	#define EXIT_SKIP_REMAINING 77
35
36	/* Put this test here for a lack of better place */
37	assert_cc(EAGAIN == EWOULDBLOCK);
38
39	static int do_spawn(	1,440✔
40	const char *path,
41	char *argv[],
42	int stdout_fd,
43	bool set_systemd_exec_pid,
44	pid_t *ret_pid) {
45
46	int r;	1,440✔
47
48	assert(path);	1,440✔
49	assert(ret_pid);	1,440✔
50
51	if (null_or_empty_path(path) > 0) {	1,440✔
52	log_debug("%s is masked, skipping.", path);	×
53	return 0;	×
54	}
55
56	pid_t pid;	1,440✔
57	r = safe_fork_full(	5,760✔
58	"(exec-inner)",
59	(const int[]) { STDIN_FILENO, stdout_fd < 0 ? STDOUT_FILENO : stdout_fd, STDERR_FILENO },	1,634✔
60	/* except_fds= / NULL, / n_except_fds= */ 0,
61	FORK_DEATHSIG_SIGTERM\|FORK_LOG\|FORK_RLIMIT_NOFILE_SAFE\|FORK_REARRANGE_STDIO\|FORK_CLOSE_ALL_FDS,
62	&pid);
63	if (r < 0)	2,880✔
64	return r;
65	if (r == 0) {	2,880✔
66	char *_argv[2];	1,440✔
67
68	if (set_systemd_exec_pid) {	1,440✔
69	r = setenv_systemd_exec_pid(false);	1,408✔
70	if (r < 0)	1,408✔
71	log_warning_errno(r, "Failed to set $SYSTEMD_EXEC_PID, ignoring: %m");	×
72	}
73
74	if (!argv) {	1,440✔
75	_argv[0] = (char*) path;	1,251✔
76	_argv[1] = NULL;	1,251✔
77	argv = _argv;	1,251✔
78	} else
79	argv[0] = (char*) path;	189✔
80
81	execv(path, argv);	1,440✔
82	log_error_errno(errno, "Failed to execute %s: %m", path);	1,440✔
83	_exit(EXIT_FAILURE);	×
84	}
85
86	*ret_pid = pid;	1,440✔
87	return 1;	1,440✔
88	}
89
90	static int do_execute(	1,426✔
91	char * const *paths,
92	const char *root,
93	usec_t timeout,
94	gather_stdout_callback_t const callbacks[_STDOUT_CONSUME_MAX],
95	void * const callback_args[_STDOUT_CONSUME_MAX],
96	int output_fd,
97	char *argv[],
98	char *envp[],
99	ExecDirFlags flags) {
100
101	_cleanup_hashmap_free_ Hashmap *pids = NULL;	1,426✔
102	bool parallel_execution;	1,426✔
103	int r;	1,426✔
104
105	/* We fork this all off from a child process so that we can somewhat cleanly make use of SIGALRM
106	* to set a time limit.
107	*
108	* We attempt to perform parallel execution if configured by the user, however if `callbacks` is nonnull,
109	* execution must be serial.
110	*/
111
112	assert(!strv_isempty(paths));	1,426✔
113
114	parallel_execution = FLAGS_SET(flags, EXEC_DIR_PARALLEL) && !callbacks;	1,426✔
115
116	/* Abort execution of this process after the timeout. We simply rely on SIGALRM as
117	* default action terminating the process, and turn on alarm(). */
118
119	if (timeout != USEC_INFINITY)	1,426✔
120	alarm(DIV_ROUND_UP(timeout, USEC_PER_SEC));	1,426✔
121
122	STRV_FOREACH(e, envp)	8,672✔
123	if (putenv(*e) != 0)	7,246✔
124	return log_error_errno(errno, "Failed to set environment variable: %m");	×
125
126	STRV_FOREACH(path, paths) {	2,865✔
127	_cleanup_free_ char *t = NULL;	1,440✔
128	_cleanup_close_ int fd = -EBADF;	1,440✔
129	pid_t pid;	1,440✔
130
131	t = path_join(root, *path);	1,440✔
132	if (!t)	1,440✔
133	return log_oom();	×
134
135	if (callbacks) {	1,440✔
136	_cleanup_free_ char *bn = NULL;	1,246✔
137
138	r = path_extract_filename(*path, &bn);	1,246✔
139	if (r < 0)	1,246✔
140	return log_error_errno(r, "Failed to extract filename from path '%s': %m", *path);	×
141
142	fd = open_serialization_fd(bn);	1,246✔
143	if (fd < 0)	1,246✔
144	return log_error_errno(fd, "Failed to open serialization file: %m");	×
145	}
146
147	if (DEBUG_LOGGING) {	1,440✔
148	_cleanup_free_ char *s = NULL;	1,013✔
149
150	char **args = strv_skip(argv, 1);	1,013✔
151	if (args)	1,013✔
152	s = quote_command_line(args, SHELL_ESCAPE_EMPTY);	×
153
154	log_debug("About to execute %s%s%s", t, args ? " " : "", args ? strnull(s) : "");	1,013✔
155	}
156
157	if (FLAGS_SET(flags, EXEC_DIR_WARN_WORLD_WRITABLE)) {	1,440✔
158	struct stat st;	178✔
159
160	r = stat(t, &st);	178✔
161	if (r < 0)	178✔
162	log_warning_errno(errno, "Failed to stat '%s', ignoring: %m", t);	178✔
163	else if (S_ISREG(st.st_mode) && (st.st_mode & 0002))	178✔
164	log_warning("'%s' is marked world-writable, which is a security risk as it "	×
165	"is executed with privileges. Please remove world writability "
166	"permission bits. Proceeding anyway.", t);
167	}
168
169	r = do_spawn(t, argv, fd, FLAGS_SET(flags, EXEC_DIR_SET_SYSTEMD_EXEC_PID), &pid);	1,440✔
170	if (r <= 0)	1,440✔
171	continue;	×
172
173	if (parallel_execution) {	1,440✔
174	r = hashmap_ensure_put(&pids, &trivial_hash_ops_value_free, PID_TO_PTR(pid), t);	192✔
175	if (r < 0)	192✔
176	return log_oom();	×
177	t = NULL;
178	} else {
179	bool skip_remaining = false;	1,248✔
180
181	r = wait_for_terminate_and_check(t, pid, WAIT_LOG_ABNORMAL);	1,248✔
182	if (r < 0)	1,248✔
183	return r;
184	if (r > 0) {	1,248✔
185	if (FLAGS_SET(flags, EXEC_DIR_SKIP_REMAINING) && r == EXIT_SKIP_REMAINING) {	1✔
186	log_info("%s succeeded with exit status %i, not executing remaining executables.", *path, r);	×
187	skip_remaining = true;
188	} else if (FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS))	1✔
189	log_warning("%s failed with exit status %i, ignoring.", *path, r);	×
190	else {
191	log_error("%s failed with exit status %i.", *path, r);	1✔
192	return r;	1✔
193	}
194	}
195
196	if (callbacks) {	1,247✔
197	r = finish_serialization_fd(fd);	1,246✔
198	if (r < 0)	1,246✔
199	return log_error_errno(r, "Failed to finish serialization fd: %m");	×
200
201	r = callbacks[STDOUT_GENERATE](TAKE_FD(fd), callback_args[STDOUT_GENERATE]);	1,246✔
202	if (r < 0)	1,246✔
203	return log_error_errno(r, "Failed to process output from %s: %m", *path);	×
204	}
205
206	if (skip_remaining)	1,247✔
207	break;
208	}
209	}
210
211	if (callbacks) {	1,425✔
212	r = callbacks[STDOUT_COLLECT](output_fd, callback_args[STDOUT_COLLECT]);	1,235✔
213	if (r < 0)	1,235✔
214	return log_error_errno(r, "Callback two failed: %m");	×
215	}
216
217	while (!hashmap_isempty(pids)) {	1,617✔
218	_cleanup_free_ char *t = NULL;	192✔
219	pid_t pid;	192✔
220	void *p;	192✔
221
222	t = ASSERT_PTR(hashmap_steal_first_key_and_value(pids, &p));	192✔
223	pid = PTR_TO_PID(p);	192✔
224	assert(pid > 0);	192✔
225
226	r = wait_for_terminate_and_check(t, pid, WAIT_LOG);	192✔
227	if (r < 0)	192✔
228	return r;
229	if (!FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS) && r > 0)	192✔
230	return r;
231	}
232
233	return 0;
234	}
235
236	int execute_strv(	888✔
237	const char *name,
238	char * const *paths,
239	const char *root,
240	usec_t timeout,
241	gather_stdout_callback_t const callbacks[_STDOUT_CONSUME_MAX],
242	void * const callback_args[_STDOUT_CONSUME_MAX],
243	char *argv[],
244	char *envp[],
245	ExecDirFlags flags) {
246
247	_cleanup_close_ int fd = -EBADF;	888✔
248	pid_t executor_pid;	888✔
249	int r;	888✔
250
251	assert(!FLAGS_SET(flags, EXEC_DIR_PARALLEL \| EXEC_DIR_SKIP_REMAINING));	888✔
252
253	if (strv_isempty(paths))	1,776✔
254	return 0;
255
256	if (callbacks) {	888✔
257	assert(name);	708✔
258	assert(callbacks[STDOUT_GENERATE]);	708✔
259	assert(callbacks[STDOUT_COLLECT]);	708✔
260	assert(callbacks[STDOUT_CONSUME]);	708✔
261	assert(callback_args);	708✔
262
263	fd = open_serialization_fd(name);	708✔
264	if (fd < 0)	708✔
265	return log_error_errno(fd, "Failed to open serialization file: %m");	×
266	}
267
268	/* Executes all binaries in the directories serially or in parallel and waits for
269	* them to finish. Optionally a timeout is applied. If a file with the same name
270	* exists in more than one directory, the earliest one wins. */
271
272	r = safe_fork("(sd-exec-strv)", FORK_RESET_SIGNALS\|FORK_DEATHSIG_SIGTERM\|FORK_LOG, &executor_pid);	888✔
273	if (r < 0)	2,314✔
274	return r;
275	if (r == 0) {	2,314✔
276	r = do_execute(paths, root, timeout, callbacks, callback_args, fd, argv, envp, flags);	1,426✔
277	_exit(r < 0 ? EXIT_FAILURE : r);	1,426✔
278	}
279
280	r = wait_for_terminate_and_check("(sd-exec-strv)", executor_pid, 0);	888✔
281	if (r < 0)	888✔
282	return r;
283	if (!FLAGS_SET(flags, EXEC_DIR_IGNORE_ERRORS) && r > 0)	888✔
284	return r;
285
286	if (!callbacks)	887✔
287	return 0;
288
289	r = finish_serialization_fd(fd);	708✔
290	if (r < 0)	708✔
291	return log_error_errno(r, "Failed to finish serialization fd: %m");	×
292
293	r = callbacks[STDOUT_CONSUME](TAKE_FD(fd), callback_args[STDOUT_CONSUME]);	708✔
294	if (r < 0)	708✔
295	return log_error_errno(r, "Failed to parse returned data: %m");	×
296
297	return 0;
298	}
299
300	int execute_directories(	888✔
301	const char * const *directories,
302	usec_t timeout,
303	gather_stdout_callback_t const callbacks[_STDOUT_CONSUME_MAX],
304	void * const callback_args[_STDOUT_CONSUME_MAX],
305	char *argv[],
306	char *envp[],
307	ExecDirFlags flags) {
308
309	_cleanup_strv_free_ char **paths = NULL;	×
310	_cleanup_free_ char *name = NULL;	888✔
311	int r;	888✔
312
313	assert(!strv_isempty((char* const*) directories));	888✔
314
315	r = conf_files_list_strv(&paths, NULL, NULL, CONF_FILES_EXECUTABLE\|CONF_FILES_REGULAR\|CONF_FILES_FILTER_MASKED, directories);	888✔
316	if (r < 0)	888✔
317	return log_error_errno(r, "Failed to enumerate executables: %m");	×
318
319	if (strv_isempty(paths)) {	888✔
320	log_debug("No executables found.");	×
321	return 0;	×
322	}
323
324	if (callbacks) {	888✔
325	r = path_extract_filename(directories[0], &name);	708✔
326	if (r < 0)	708✔
327	return log_error_errno(r, "Failed to extract file name from '%s': %m", directories[0]);	×
328	}
329
330	return execute_strv(name, paths, /* root = */ NULL, timeout, callbacks, callback_args, argv, envp, flags);	888✔
331	}
332
333	static int gather_environment_generate(int fd, void *arg) {	1,236✔
334	char ***env = ASSERT_PTR(arg);	1,236✔
335	_cleanup_fclose_ FILE *f = NULL;	1,236✔
336	_cleanup_strv_free_ char **new = NULL;	1,236✔
337	int r;	1,236✔
338
339	/* Read a series of VAR=value assignments from fd, use them to update the list of variables in env.
340	* Also update the exported environment.
341	*
342	* fd is always consumed, even on error.
343	*/
344
345	assert(fd >= 0);	1,236✔
346
347	f = fdopen(fd, "r");	1,236✔
348	if (!f) {	1,236✔
349	safe_close(fd);	×
350	return -errno;	×
351	}
352
353	r = load_env_file_pairs(f, NULL, &new);	1,236✔
354	if (r < 0)	1,236✔
355	return r;
356
357	STRV_FOREACH_PAIR(x, y, new) {	2,312✔
358	if (!env_name_is_valid(*x)) {	1,076✔
359	log_warning("Invalid variable assignment \"%s=...\", ignoring.", *x);	4✔
360	continue;	4✔
361	}
362
363	r = strv_env_assign(env, x, y);	1,072✔
364	if (r < 0)	1,072✔
365	return r;
366
367	if (setenv(x, y, /* overwrite = */ true) < 0)	1,072✔
368	return -errno;	×
369	}
370
371	return 0;
372	}
373
374	static int gather_environment_collect(int fd, void *arg) {	1,232✔
375	char ***env = ASSERT_PTR(arg);	1,232✔
376	_cleanup_fclose_ FILE *f = NULL;	1,232✔
377	int r;	1,232✔
378
379	/* Write out a series of env=cescape(VAR=value) assignments to fd. */
380
381	assert(fd >= 0);	1,232✔
382
383	f = fdopen(fd, "w");	1,232✔
384	if (!f) {	1,232✔
385	safe_close(fd);	×
386	return -errno;	×
387	}
388
389	r = serialize_strv(f, "env", *env);	1,232✔
390	if (r < 0)	1,232✔
391	return r;
392
393	r = fflush_and_check(f);	1,232✔
394	if (r < 0)	1,232✔
395	return r;	×
396
397	return 0;
398	}
399
400	static int gather_environment_consume(int fd, void *arg) {	705✔
401	char ***env = ASSERT_PTR(arg);	705✔
402	_cleanup_fclose_ FILE *f = NULL;	705✔
403	int r, ret = 0;	705✔
404
405	/* Read a series of env=cescape(VAR=value) assignments from fd into env. */
406
407	assert(fd >= 0);	705✔
408
409	f = fdopen(fd, "r");	705✔
410	if (!f) {	705✔
411	safe_close(fd);	×
412	return -errno;	×
413	}
414
415	for (;;) {	1,246✔
416	_cleanup_free_ char *line = NULL;	1,246✔
417	const char *v;	1,246✔
418
419	r = read_line(f, LONG_LINE_MAX, &line);	1,246✔
420	if (r < 0)	1,246✔
421	return r;
422	if (r == 0)	1,246✔
423	return ret;
424
425	v = startswith(line, "env=");	541✔
426	if (!v) {	541✔
427	RET_GATHER(ret, log_debug_errno(SYNTHETIC_ERRNO(EINVAL),	×
428	"Serialization line unexpectedly didn't start with \"env=\", ignoring: %s",
429	line));
430	continue;	×
431	}
432
433	r = deserialize_environment(v, env);	541✔
434	if (r < 0)	541✔
435	RET_GATHER(ret, log_debug_errno(r, "Failed to deserialize line \"%s\": %m", line));	×
436	}
437	}
438
439	const gather_stdout_callback_t gather_environment[_STDOUT_CONSUME_MAX] = {
440	gather_environment_generate,
441	gather_environment_collect,
442	gather_environment_consume,
443	};
444
445	int exec_command_flags_from_strv(char * const ex_opts, ExecCommandFlags ret) {	323✔
446	ExecCommandFlags flags = 0;	323✔
447
448	assert(ret);	323✔
449
450	STRV_FOREACH(opt, ex_opts) {	361✔
451	ExecCommandFlags fl = exec_command_flags_from_string(*opt);	39✔
452	if (fl < 0)	39✔
453	return fl;
454
455	flags \|= fl;	38✔
456	}
457
458	*ret = flags;	322✔
459
460	return 0;	322✔
461	}
462
463	int exec_command_flags_to_strv(ExecCommandFlags flags, char ***ret) {	1,434✔
464	_cleanup_strv_free_ char **opts = NULL;	1,434✔
465	int r;	1,434✔
466
467	assert(flags >= 0);	1,434✔
468	assert(ret);	1,434✔
469
470	BIT_FOREACH(i, flags) {	1,686✔
471	const char *s = exec_command_flags_to_string(1 << i);	253✔
472	if (!s)	253✔
473	return -EINVAL;
474
475	r = strv_extend(&opts, s);	252✔
476	if (r < 0)	252✔
477	return r;
478	}
479
480	*ret = TAKE_PTR(opts);	1,433✔
481
482	return 0;	1,433✔
483	}
484
485	static const char* const exec_command_strings[] = {
486	"ignore-failure", /* EXEC_COMMAND_IGNORE_FAILURE */
487	"privileged", /* EXEC_COMMAND_FULLY_PRIVILEGED */
488	"no-setuid", /* EXEC_COMMAND_NO_SETUID */
489	"no-env-expand", /* EXEC_COMMAND_NO_ENV_EXPAND */
490	"via-shell", /* EXEC_COMMAND_VIA_SHELL */
491	};
492
493	assert_cc((1 << ELEMENTSOF(exec_command_strings)) - 1 == _EXEC_COMMAND_FLAGS_ALL);
494
495	const char* exec_command_flags_to_string(ExecCommandFlags i) {	253✔
496	for (size_t idx = 0; idx < ELEMENTSOF(exec_command_strings); idx++)	858✔
497	if (i == (1 << idx))	857✔
498	return exec_command_strings[idx];	252✔
499
500	return NULL;
501	}
502
503	ExecCommandFlags exec_command_flags_from_string(const char *s) {	39✔
504	ssize_t idx;	39✔
505
506	if (streq(s, "ambient")) /* Compatibility with ambient hack, removed in v258, map to no bits set */	39✔
507	return 0;
508
509	idx = string_table_lookup_from_string(exec_command_strings, ELEMENTSOF(exec_command_strings), s);	39✔
510	if (idx < 0)	39✔
511	return _EXEC_COMMAND_FLAGS_INVALID;
512
513	return 1 << idx;	38✔
514	}
515
516	int fexecve_or_execve(int executable_fd, const char executable, char const argv[], char *const envp[]) {	21,557✔
517	/* Refuse invalid fds, regardless if fexecve() use is enabled or not */
518	if (executable_fd < 0)	21,557✔
519	return -EBADF;
520
521	/* Block any attempts on exploiting Linux' liberal argv[] handling, i.e. CVE-2021-4034 and suchlike */
522	if (isempty(executable) \|\| strv_isempty(argv))	43,114✔
523	return -EINVAL;
524
525	#if ENABLE_FEXECVE
526
527	execveat(executable_fd, "", argv, envp, AT_EMPTY_PATH);
528
529	if (IN_SET(errno, ENOSYS, ENOENT) \|\| ERRNO_IS_PRIVILEGE(errno))
530	/* Old kernel or a script or an overzealous seccomp filter? Let's fall back to execve().
531	*
532	* fexecve(3): "If fd refers to a script (i.e., it is an executable text file that names a
533	* script interpreter with a first line that begins with the characters #!) and the
534	* close-on-exec flag has been set for fd, then fexecve() fails with the error ENOENT. This
535	* error occurs because, by the time the script interpreter is executed, fd has already been
536	* closed because of the close-on-exec flag. Thus, the close-on-exec flag can't be set on fd
537	* if it refers to a script."
538	*
539	* Unfortunately, if we unset close-on-exec, the script will be executed just fine, but (at
540	* least in case of bash) the script name, $0, will be shown as /dev/fd/nnn, which breaks
541	* scripts which make use of $0. Thus, let's fall back to execve() in this case.
542	*/
543	#endif
544	execve(executable, argv, envp);	21,557✔
545	return -errno;	21,557✔
546	}
547
548	int shall_fork_agent(void) {	3,052✔
549	int r;	3,052✔
550
551	/* Check if we have a controlling terminal. If not (ENXIO here), we aren't actually invoked
552	* interactively on a terminal, hence fail. */
553	r = get_ctty_devnr(0, NULL);	3,052✔
554	if (r == -ENXIO)	3,052✔
555	return false;
556	if (r < 0)	×
557	return r;
558
559	if (!is_main_thread())	×
560	return -EPERM;	×
561
562	return true;
563	}
564
565	int _fork_agent(const char name, char const argv, const int except[], size_t n_except, pid_t ret_pid) {	×
566	int r;	×
567
568	assert(!strv_isempty(argv));	×
569
570	/* Spawns a temporary TTY agent, making sure it goes away when we go away */
571
572	r = safe_fork_full(name,	×
573	NULL,
574	(int) except, / safe_fork_full only changes except if you pass in FORK_PACK_FDS, which we don't */
575	n_except,
576	FORK_RESET_SIGNALS\|FORK_DEATHSIG_SIGTERM\|FORK_CLOSE_ALL_FDS\|FORK_REOPEN_LOG\|FORK_RLIMIT_NOFILE_SAFE,
577	ret_pid);
578	if (r < 0)	×
579	return r;
580	if (r > 0)	×
581	return 0;
582
583	/* In the child: */
584
585	bool stdin_is_tty = isatty_safe(STDIN_FILENO),	×
586	stdout_is_tty = isatty_safe(STDOUT_FILENO),	×
587	stderr_is_tty = isatty_safe(STDERR_FILENO);	×
588
589	if (!stdin_is_tty \|\| !stdout_is_tty \|\| !stderr_is_tty) {	×
590	int fd;	×
591
592	/* Detach from stdin/stdout/stderr and reopen /dev/tty for them. This is important to ensure
593	* that when systemctl is started via popen() or a similar call that expects to read EOF we
594	* actually do generate EOF and not delay this indefinitely by keeping an unused copy of
595	* stdin around. */
596	fd = open_terminal("/dev/tty", stdin_is_tty ? O_WRONLY : (stdout_is_tty && stderr_is_tty) ? O_RDONLY : O_RDWR);	×
597	if (fd < 0) {	×
598	log_error_errno(fd, "Failed to open /dev/tty: %m");	×
599	_exit(EXIT_FAILURE);	×
600	}
601
602	if (!stdin_is_tty && dup2(fd, STDIN_FILENO) < 0) {	×
603	log_error_errno(errno, "Failed to dup2 /dev/tty to STDIN: %m");	×
604	_exit(EXIT_FAILURE);	×
605	}
606
607	if (!stdout_is_tty && dup2(fd, STDOUT_FILENO) < 0) {	×
608	log_error_errno(errno, "Failed to dup2 /dev/tty to STDOUT: %m");	×
609	_exit(EXIT_FAILURE);	×
610	}
611
612	if (!stderr_is_tty && dup2(fd, STDERR_FILENO) < 0) {	×
613	log_error_errno(errno, "Failed to dup2 /dev/tty to STDERR: %m");	×
614	_exit(EXIT_FAILURE);	×
615	}
616
617	fd = safe_close_above_stdio(fd);	×
618	}
619
620	/* Count arguments */
621	execv(argv[0], argv);	×
622
623	/* Let's treat missing agent binary as a graceful issue (in order to support splitting out the Polkit
624	* or password agents into separate, optional distro packages), and not complain loudly. */
625	log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno,	×
626	"Failed to execute %s: %m", argv[0]);
627	_exit(EXIT_FAILURE);	×
628	}

systemd / systemd / 15057632786

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