1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2013 Zbigniew Jędrzejewski-Szmek
7 systemd is free software; you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or
10 (at your option) any later version.
12 systemd is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <sys/epoll.h>
23 #include <sys/prctl.h>
24 #include <sys/socket.h>
28 #include "sd-daemon.h"
30 #include "alloc-util.h"
35 #include "process-util.h"
36 #include "signal-util.h"
37 #include "socket-util.h"
38 #include "string-util.h"
41 static char** arg_listen
= NULL
;
42 static bool arg_accept
= false;
43 static int arg_socket_type
= SOCK_STREAM
;
44 static char** arg_args
= NULL
;
45 static char** arg_setenv
= NULL
;
46 static char **arg_fdnames
= NULL
;
47 static bool arg_inetd
= false;
49 static int add_epoll(int epoll_fd
, int fd
) {
50 struct epoll_event ev
= {
55 assert(epoll_fd
>= 0);
59 r
= epoll_ctl(epoll_fd
, EPOLL_CTL_ADD
, fd
, &ev
);
61 return log_error_errno(errno
, "Failed to add event on epoll fd:%d for fd:%d: %m", epoll_fd
, fd
);
66 static int open_sockets(int *epoll_fd
, bool accept
) {
71 n
= sd_listen_fds(true);
73 return log_error_errno(n
, "Failed to read listening file descriptors from environment: %m");
75 log_info("Received %i descriptors via the environment.", n
);
77 for (fd
= SD_LISTEN_FDS_START
; fd
< SD_LISTEN_FDS_START
+ n
; fd
++) {
78 r
= fd_cloexec(fd
, arg_accept
);
86 /* Close logging and all other descriptors */
90 for (fd
= 0; fd
< SD_LISTEN_FDS_START
+ n
; fd
++)
94 close_all_fds(except
, 3 + n
);
97 /** Note: we leak some fd's on error here. I doesn't matter
98 * much, since the program will exit immediately anyway, but
99 * would be a pain to fix.
102 STRV_FOREACH(address
, arg_listen
) {
103 fd
= make_socket_fd(LOG_DEBUG
, *address
, arg_socket_type
, (arg_accept
*SOCK_CLOEXEC
));
106 return log_error_errno(fd
, "Failed to open '%s': %m", *address
);
109 assert(fd
== SD_LISTEN_FDS_START
+ count
);
116 *epoll_fd
= epoll_create1(EPOLL_CLOEXEC
);
118 return log_error_errno(errno
, "Failed to create epoll object: %m");
120 for (fd
= SD_LISTEN_FDS_START
; fd
< SD_LISTEN_FDS_START
+ count
; fd
++) {
121 _cleanup_free_
char *name
= NULL
;
123 getsockname_pretty(fd
, &name
);
124 log_info("Listening on %s as %i.", strna(name
), fd
);
126 r
= add_epoll(*epoll_fd
, fd
);
134 static int exec_process(const char* name
, char **argv
, char **env
, int start_fd
, int n_fds
) {
136 _cleanup_strv_free_
char **envp
= NULL
;
137 _cleanup_free_
char *joined
= NULL
;
138 unsigned n_env
= 0, length
;
143 if (arg_inetd
&& n_fds
!= 1) {
144 log_error("--inetd only supported for single file descriptors.");
148 length
= strv_length(arg_setenv
);
150 /* PATH, TERM, HOME, USER, LISTEN_FDS, LISTEN_PID, LISTEN_FDNAMES, NULL */
151 envp
= new0(char *, length
+ 8);
155 STRV_FOREACH(s
, arg_setenv
) {
157 if (strchr(*s
, '=')) {
166 _cleanup_free_
char *p
;
169 p
= strappend(*s
, "=");
173 n
= strv_find_prefix(env
, p
);
177 envp
[n_env
] = strdup(n
);
185 FOREACH_STRING(tocopy
, "TERM=", "PATH=", "USER=", "HOME=") {
188 n
= strv_find_prefix(env
, tocopy
);
192 envp
[n_env
] = strdup(n
);
202 r
= dup2(start_fd
, STDIN_FILENO
);
204 return log_error_errno(errno
, "Failed to dup connection to stdin: %m");
206 r
= dup2(start_fd
, STDOUT_FILENO
);
208 return log_error_errno(errno
, "Failed to dup connection to stdout: %m");
210 start_fd
= safe_close(start_fd
);
212 if (start_fd
!= SD_LISTEN_FDS_START
) {
215 r
= dup2(start_fd
, SD_LISTEN_FDS_START
);
217 return log_error_errno(errno
, "Failed to dup connection: %m");
219 safe_close(start_fd
);
220 start_fd
= SD_LISTEN_FDS_START
;
223 if (asprintf((char**)(envp
+ n_env
++), "LISTEN_FDS=%i", n_fds
) < 0)
226 if (asprintf((char**)(envp
+ n_env
++), "LISTEN_PID=" PID_FMT
, getpid_cached()) < 0)
230 _cleanup_free_
char *names
= NULL
;
235 len
= strv_length(arg_fdnames
);
237 for (i
= 1; i
< n_fds
; i
++) {
238 r
= strv_extend(&arg_fdnames
, arg_fdnames
[0]);
240 return log_error_errno(r
, "Failed to extend strv: %m");
242 else if (len
!= (unsigned) n_fds
)
243 log_warning("The number of fd names is different than number of fds: %zu vs %d",
246 names
= strv_join(arg_fdnames
, ":");
250 e
= strappend("LISTEN_FDNAMES=", names
);
258 joined
= strv_join(argv
, " ");
262 log_info("Execing %s (%s)", name
, joined
);
263 execvpe(name
, argv
, envp
);
265 return log_error_errno(errno
, "Failed to execp %s (%s): %m", name
, joined
);
268 static int fork_and_exec_process(const char* child
, char** argv
, char **env
, int fd
) {
269 _cleanup_free_
char *joined
= NULL
;
273 joined
= strv_join(argv
, " ");
277 r
= safe_fork("(activate)", FORK_RESET_SIGNALS
|FORK_DEATHSIG
|FORK_LOG
, &child_pid
);
282 exec_process(child
, argv
, env
, fd
, 1);
286 log_info("Spawned %s (%s) as PID " PID_FMT
".", child
, joined
, child_pid
);
290 static int do_accept(const char* name
, char **argv
, char **envp
, int fd
) {
291 _cleanup_free_
char *local
= NULL
, *peer
= NULL
;
292 _cleanup_close_
int fd_accepted
= -1;
294 fd_accepted
= accept4(fd
, NULL
, NULL
, 0);
296 return log_error_errno(errno
, "Failed to accept connection on fd:%d: %m", fd
);
298 getsockname_pretty(fd_accepted
, &local
);
299 getpeername_pretty(fd_accepted
, true, &peer
);
300 log_info("Connection from %s to %s", strna(peer
), strna(local
));
302 return fork_and_exec_process(name
, argv
, envp
, fd_accepted
);
305 /* SIGCHLD handler. */
306 static void sigchld_hdl(int sig
) {
314 r
= waitid(P_ALL
, 0, &si
, WEXITED
|WNOHANG
);
317 log_error_errno(errno
, "Failed to reap children: %m");
323 log_info("Child %d died with code %d", si
.si_pid
, si
.si_status
);
327 static int install_chld_handler(void) {
328 static const struct sigaction act
= {
329 .sa_flags
= SA_NOCLDSTOP
|SA_RESTART
,
330 .sa_handler
= sigchld_hdl
,
335 r
= sigaction(SIGCHLD
, &act
, 0);
337 return log_error_errno(errno
, "Failed to install SIGCHLD handler: %m");
342 static void help(void) {
343 printf("%s [OPTIONS...]\n\n"
344 "Listen on sockets and launch child on connection.\n\n"
346 " -h --help Show this help and exit\n"
347 " --version Print version string and exit\n"
348 " -l --listen=ADDR Listen for raw connections at ADDR\n"
349 " -d --datagram Listen on datagram instead of stream socket\n"
350 " --seqpacket Listen on SOCK_SEQPACKET instead of stream socket\n"
351 " -a --accept Spawn separate child for each connection\n"
352 " -E --setenv=NAME[=VALUE] Pass an environment variable to children\n"
353 " --fdname=NAME[:NAME...] Specify names for file descriptors\n"
354 " --inetd Enable inetd file descriptor passing protocol\n"
356 "Note: file descriptors from sd_listen_fds() will be passed through.\n"
357 , program_invocation_short_name
);
360 static int parse_argv(int argc
, char *argv
[]) {
368 static const struct option options
[] = {
369 { "help", no_argument
, NULL
, 'h' },
370 { "version", no_argument
, NULL
, ARG_VERSION
},
371 { "datagram", no_argument
, NULL
, 'd' },
372 { "seqpacket", no_argument
, NULL
, ARG_SEQPACKET
},
373 { "listen", required_argument
, NULL
, 'l' },
374 { "accept", no_argument
, NULL
, 'a' },
375 { "setenv", required_argument
, NULL
, 'E' },
376 { "environment", required_argument
, NULL
, 'E' }, /* legacy alias */
377 { "fdname", required_argument
, NULL
, ARG_FDNAME
},
378 { "inetd", no_argument
, NULL
, ARG_INETD
},
387 while ((c
= getopt_long(argc
, argv
, "+hl:aE:d", options
, NULL
)) >= 0)
397 r
= strv_extend(&arg_listen
, optarg
);
404 if (arg_socket_type
== SOCK_SEQPACKET
) {
405 log_error("--datagram may not be combined with --seqpacket.");
409 arg_socket_type
= SOCK_DGRAM
;
413 if (arg_socket_type
== SOCK_DGRAM
) {
414 log_error("--seqpacket may not be combined with --datagram.");
418 arg_socket_type
= SOCK_SEQPACKET
;
426 r
= strv_extend(&arg_setenv
, optarg
);
433 _cleanup_strv_free_
char **names
;
436 names
= strv_split(optarg
, ":");
440 STRV_FOREACH(s
, names
)
441 if (!fdname_is_valid(*s
)) {
442 _cleanup_free_
char *esc
;
445 log_warning("File descriptor name \"%s\" is not valid.", esc
);
448 /* Empty optargs means one empty name */
449 r
= strv_extend_strv(&arg_fdnames
,
450 strv_isempty(names
) ? STRV_MAKE("") : names
,
453 return log_error_errno(r
, "strv_extend_strv: %m");
465 assert_not_reached("Unhandled option");
468 if (optind
== argc
) {
469 log_error("%s: command to execute is missing.",
470 program_invocation_short_name
);
474 if (arg_socket_type
== SOCK_DGRAM
&& arg_accept
) {
475 log_error("Datagram sockets do not accept connections. "
476 "The --datagram and --accept options may not be combined.");
480 arg_args
= argv
+ optind
;
482 return 1 /* work to do */;
485 int main(int argc
, char **argv
, char **envp
) {
489 log_parse_environment();
492 r
= parse_argv(argc
, argv
);
494 return r
== 0 ? EXIT_SUCCESS
: EXIT_FAILURE
;
496 r
= install_chld_handler();
500 n
= open_sockets(&epoll_fd
, arg_accept
);
504 log_error("No sockets to listen on specified or passed in.");
509 struct epoll_event event
;
511 r
= epoll_wait(epoll_fd
, &event
, 1, -1);
516 log_error_errno(errno
, "epoll_wait() failed: %m");
520 log_info("Communication attempt on fd %i.", event
.data
.fd
);
522 r
= do_accept(argv
[optind
], argv
+ optind
, envp
, event
.data
.fd
);
529 exec_process(argv
[optind
], argv
+ optind
, envp
, SD_LISTEN_FDS_START
, n
);