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/>.
23 #include <sys/epoll.h>
24 #include <sys/prctl.h>
25 #include <sys/socket.h>
29 #include "systemd/sd-daemon.h"
31 #include "socket-util.h"
36 #include "signal-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) {
197 (void) reset_all_signal_handlers();
198 (void) reset_signal_mask();
200 r
= dup2(fd
, STDIN_FILENO
);
202 log_error_errno(errno
, "Failed to dup connection to stdin: %m");
206 r
= dup2(fd
, STDOUT_FILENO
);
208 log_error_errno(errno
, "Failed to dup connection to stdout: %m");
214 log_error_errno(errno
, "Failed to close dupped connection: %m");
218 /* Make sure the child goes away when the parent dies */
219 if (prctl(PR_SET_PDEATHSIG
, SIGTERM
) < 0)
222 /* Check whether our parent died before we were able
223 * to set the death signal */
224 if (getppid() != parent_pid
)
228 log_error_errno(errno
, "Failed to exec child %s: %m", child
);
232 log_info("Spawned %s (%s) as PID %d", child
, tmp
, child_pid
);
237 static int do_accept(const char* name
, char **argv
, char **envp
, int fd
) {
238 _cleanup_free_
char *local
= NULL
, *peer
= NULL
;
239 _cleanup_close_
int fd2
= -1;
241 fd2
= accept(fd
, NULL
, NULL
);
243 log_error_errno(errno
, "Failed to accept connection on fd:%d: %m", fd
);
247 getsockname_pretty(fd2
, &local
);
248 getpeername_pretty(fd2
, &peer
);
249 log_info("Connection from %s to %s", strna(peer
), strna(local
));
251 return launch1(name
, argv
, envp
, fd2
);
254 /* SIGCHLD handler. */
255 static void sigchld_hdl(int sig
, siginfo_t
*t
, void *data
) {
258 log_info("Child %d died with code %d", t
->si_pid
, t
->si_status
);
259 /* Wait for a dead child. */
260 waitpid(t
->si_pid
, NULL
, 0);
263 static int install_chld_handler(void) {
265 struct sigaction act
= {
266 .sa_flags
= SA_SIGINFO
,
267 .sa_sigaction
= sigchld_hdl
,
270 r
= sigaction(SIGCHLD
, &act
, 0);
272 log_error_errno(errno
, "Failed to install SIGCHLD handler: %m");
276 static void help(void) {
277 printf("%s [OPTIONS...]\n\n"
278 "Listen on sockets and launch child on connection.\n\n"
280 " -l --listen=ADDR Listen for raw connections at ADDR\n"
281 " -a --accept Spawn separate child for each connection\n"
282 " -h --help Show this help and exit\n"
283 " -E --setenv=NAME[=VALUE] Pass an environment variable to children\n"
284 " --version Print version string and exit\n"
286 "Note: file descriptors from sd_listen_fds() will be passed through.\n"
287 , program_invocation_short_name
);
290 static int parse_argv(int argc
, char *argv
[]) {
295 static const struct option options
[] = {
296 { "help", no_argument
, NULL
, 'h' },
297 { "version", no_argument
, NULL
, ARG_VERSION
},
298 { "listen", required_argument
, NULL
, 'l' },
299 { "accept", no_argument
, NULL
, 'a' },
300 { "setenv", required_argument
, NULL
, 'E' },
301 { "environment", required_argument
, NULL
, 'E' }, /* alias */
310 while ((c
= getopt_long(argc
, argv
, "+hl:aE:", options
, NULL
)) >= 0)
317 puts(PACKAGE_STRING
);
318 puts(SYSTEMD_FEATURES
);
322 int r
= strv_extend(&arg_listen
, optarg
);
334 int r
= strv_extend(&arg_setenv
, optarg
);
345 assert_not_reached("Unhandled option");
348 if (optind
== argc
) {
349 log_error("%s: command to execute is missing.",
350 program_invocation_short_name
);
354 arg_args
= argv
+ optind
;
356 return 1 /* work to do */;
359 int main(int argc
, char **argv
, char **envp
) {
363 log_parse_environment();
366 r
= parse_argv(argc
, argv
);
368 return r
== 0 ? EXIT_SUCCESS
: EXIT_FAILURE
;
370 r
= install_chld_handler();
374 n
= open_sockets(&epoll_fd
, arg_accept
);
378 log_error("No sockets to listen on specified or passed in.");
383 struct epoll_event event
;
385 r
= epoll_wait(epoll_fd
, &event
, 1, -1);
390 log_error_errno(errno
, "epoll_wait() failed: %m");
394 log_info("Communication attempt on fd %i.", event
.data
.fd
);
396 r
= do_accept(argv
[optind
], argv
+ optind
, envp
,
404 launch(argv
[optind
], argv
+ optind
, envp
, n
);