1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2013 Zbigniew Jędrzejewski-Szmek
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 #include <sys/epoll.h>
25 #include <sys/prctl.h>
26 #include <sys/socket.h>
30 #include "systemd/sd-daemon.h"
32 #include "socket-util.h"
38 static char** arg_listen = NULL;
39 static bool arg_accept = false;
40 static char** arg_args = NULL;
41 static char** arg_setenv = NULL;
43 static int add_epoll(int epoll_fd, int fd) {
44 struct epoll_event ev = {
49 assert(epoll_fd >= 0);
53 r = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev);
55 return log_error_errno(errno, "Failed to add event on epoll fd:%d for fd:%d: %m", epoll_fd, fd);
60 static int open_sockets(int *epoll_fd, bool accept) {
65 n = sd_listen_fds(true);
67 return log_error_errno(n, "Failed to read listening file descriptors from environment: %m");
69 log_info("Received %i descriptors via the environment.", n);
71 for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
72 r = fd_cloexec(fd, arg_accept);
80 /* Close logging and all other descriptors */
84 for (fd = 0; fd < SD_LISTEN_FDS_START + n; fd++)
88 close_all_fds(except, 3 + n);
91 /** Note: we leak some fd's on error here. I doesn't matter
92 * much, since the program will exit immediately anyway, but
93 * would be a pain to fix.
96 STRV_FOREACH(address, arg_listen) {
98 fd = make_socket_fd(LOG_DEBUG, *address, SOCK_STREAM | (arg_accept*SOCK_CLOEXEC));
101 return log_error_errno(fd, "Failed to open '%s': %m", *address);
104 assert(fd == SD_LISTEN_FDS_START + count);
111 *epoll_fd = epoll_create1(EPOLL_CLOEXEC);
113 return log_error_errno(errno, "Failed to create epoll object: %m");
115 for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + count; fd++) {
116 _cleanup_free_ char *name = NULL;
118 getsockname_pretty(fd, &name);
119 log_info("Listening on %s as %i.", strna(name), fd);
121 r = add_epoll(*epoll_fd, fd);
129 static int launch(char* name, char **argv, char **env, int fds) {
131 static const char* tocopy[] = {"TERM=", "PATH=", "USER=", "HOME="};
132 _cleanup_strv_free_ char **envp = NULL;
133 _cleanup_free_ char *tmp = NULL;
134 unsigned n_env = 0, length;
138 length = strv_length(arg_setenv);
140 /* PATH, TERM, HOME, USER, LISTEN_FDS, LISTEN_PID, NULL */
141 envp = new0(char *, length + 7);
145 STRV_FOREACH(s, arg_setenv) {
149 _cleanup_free_ char *p = strappend(*s, "=");
152 envp[n_env] = strv_find_prefix(env, p);
158 for (i = 0; i < ELEMENTSOF(tocopy); i++) {
159 envp[n_env] = strv_find_prefix(env, tocopy[i]);
164 if ((asprintf((char**)(envp + n_env++), "LISTEN_FDS=%d", fds) < 0) ||
165 (asprintf((char**)(envp + n_env++), "LISTEN_PID=%d", getpid()) < 0))
168 tmp = strv_join(argv, " ");
172 log_info("Execing %s (%s)", name, tmp);
173 execvpe(name, argv, envp);
174 log_error_errno(errno, "Failed to execp %s (%s): %m", name, tmp);
179 static int launch1(const char* child, char** argv, char **env, int fd) {
180 _cleanup_free_ char *tmp = NULL;
181 pid_t parent_pid, child_pid;
184 tmp = strv_join(argv, " ");
188 parent_pid = getpid();
192 return log_error_errno(errno, "Failed to fork: %m");
195 if (child_pid == 0) {
196 r = dup2(fd, STDIN_FILENO);
198 log_error_errno(errno, "Failed to dup connection to stdin: %m");
202 r = dup2(fd, STDOUT_FILENO);
204 log_error_errno(errno, "Failed to dup connection to stdout: %m");
210 log_error_errno(errno, "Failed to close dupped connection: %m");
214 /* Make sure the child goes away when the parent dies */
215 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
218 /* Check whether our parent died before we were able
219 * to set the death signal */
220 if (getppid() != parent_pid)
224 log_error_errno(errno, "Failed to exec child %s: %m", child);
228 log_info("Spawned %s (%s) as PID %d", child, tmp, child_pid);
233 static int do_accept(const char* name, char **argv, char **envp, int fd) {
234 _cleanup_free_ char *local = NULL, *peer = NULL;
235 _cleanup_close_ int fd2 = -1;
237 fd2 = accept(fd, NULL, NULL);
239 log_error_errno(errno, "Failed to accept connection on fd:%d: %m", fd);
243 getsockname_pretty(fd2, &local);
244 getpeername_pretty(fd2, &peer);
245 log_info("Connection from %s to %s", strna(peer), strna(local));
247 return launch1(name, argv, envp, fd2);
250 /* SIGCHLD handler. */
251 static void sigchld_hdl(int sig, siginfo_t *t, void *data) {
254 log_info("Child %d died with code %d", t->si_pid, t->si_status);
255 /* Wait for a dead child. */
256 waitpid(t->si_pid, NULL, 0);
259 static int install_chld_handler(void) {
261 struct sigaction act = {
262 .sa_flags = SA_SIGINFO,
263 .sa_sigaction = sigchld_hdl,
266 r = sigaction(SIGCHLD, &act, 0);
268 log_error_errno(errno, "Failed to install SIGCHLD handler: %m");
272 static void help(void) {
273 printf("%s [OPTIONS...]\n\n"
274 "Listen on sockets and launch child on connection.\n\n"
276 " -l --listen=ADDR Listen for raw connections at ADDR\n"
277 " -a --accept Spawn separate child for each connection\n"
278 " -h --help Show this help and exit\n"
279 " -E --setenv=NAME[=VALUE] Pass an environment variable to children\n"
280 " --version Print version string and exit\n"
282 "Note: file descriptors from sd_listen_fds() will be passed through.\n"
283 , program_invocation_short_name);
286 static int parse_argv(int argc, char *argv[]) {
291 static const struct option options[] = {
292 { "help", no_argument, NULL, 'h' },
293 { "version", no_argument, NULL, ARG_VERSION },
294 { "listen", required_argument, NULL, 'l' },
295 { "accept", no_argument, NULL, 'a' },
296 { "setenv", required_argument, NULL, 'E' },
297 { "environment", required_argument, NULL, 'E' }, /* alias */
306 while ((c = getopt_long(argc, argv, "+hl:aE:", options, NULL)) >= 0)
313 puts(PACKAGE_STRING);
314 puts(SYSTEMD_FEATURES);
318 int r = strv_extend(&arg_listen, optarg);
330 int r = strv_extend(&arg_setenv, optarg);
341 assert_not_reached("Unhandled option");
344 if (optind == argc) {
345 log_error("%s: command to execute is missing.",
346 program_invocation_short_name);
350 arg_args = argv + optind;
352 return 1 /* work to do */;
355 int main(int argc, char **argv, char **envp) {
359 log_parse_environment();
362 r = parse_argv(argc, argv);
364 return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
366 r = install_chld_handler();
370 n = open_sockets(&epoll_fd, arg_accept);
374 log_error("No sockets to listen on specified or passed in.");
379 struct epoll_event event;
381 r = epoll_wait(epoll_fd, &event, 1, -1);
386 log_error_errno(errno, "epoll_wait() failed: %m");
390 log_info("Communication attempt on fd %i.", event.data.fd);
392 r = do_accept(argv[optind], argv + optind, envp,
400 launch(argv[optind], argv + optind, envp, n);