blob: 37abb4cc5148b1b3c1679b5897c7b939abf98b0c [file] [log] [blame]
Willy Tarreau92fb9832007-10-16 17:34:28 +02001/*
2 * UNIX SOCK_STREAM protocol layer (uxst)
3 *
Willy Tarreaueb472682010-05-28 18:46:57 +02004 * Copyright 2000-2010 Willy Tarreau <w@1wt.eu>
Willy Tarreau92fb9832007-10-16 17:34:28 +02005 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 */
12
13#include <ctype.h>
14#include <errno.h>
15#include <fcntl.h>
16#include <stdio.h>
17#include <stdlib.h>
18#include <string.h>
19#include <syslog.h>
20#include <time.h>
21
Willy Tarreau92fb9832007-10-16 17:34:28 +020022#include <sys/socket.h>
23#include <sys/stat.h>
24#include <sys/types.h>
25#include <sys/un.h>
26
27#include <common/compat.h>
28#include <common/config.h>
29#include <common/debug.h>
Willy Tarreaud740bab2007-10-28 11:14:07 +010030#include <common/errors.h>
Willy Tarreau92fb9832007-10-16 17:34:28 +020031#include <common/mini-clist.h>
32#include <common/standard.h>
33#include <common/time.h>
34#include <common/version.h>
35
Willy Tarreau92fb9832007-10-16 17:34:28 +020036#include <types/global.h>
Willy Tarreau92fb9832007-10-16 17:34:28 +020037
Willy Tarreau92fb9832007-10-16 17:34:28 +020038#include <proto/fd.h>
39#include <proto/log.h>
40#include <proto/protocols.h>
41#include <proto/proto_uxst.h>
Willy Tarreau92fb9832007-10-16 17:34:28 +020042#include <proto/stream_sock.h>
43#include <proto/task.h>
44
Emeric Bruncf20bf12010-10-22 16:06:11 +020045static int uxst_bind_listener(struct listener *listener, char *errmsg, int errlen);
46static int uxst_bind_listeners(struct protocol *proto, char *errmsg, int errlen);
Willy Tarreaudabf2e22007-10-28 21:59:24 +010047static int uxst_unbind_listeners(struct protocol *proto);
48
49/* Note: must not be declared <const> as its list will be overwritten */
50static struct protocol proto_unix = {
51 .name = "unix_stream",
52 .sock_domain = PF_UNIX,
53 .sock_type = SOCK_STREAM,
54 .sock_prot = 0,
55 .sock_family = AF_UNIX,
56 .sock_addrlen = sizeof(struct sockaddr_un),
57 .l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),/* path len */
Willy Tarreaueb472682010-05-28 18:46:57 +020058 .accept = &stream_sock_accept,
Willy Tarreaudabf2e22007-10-28 21:59:24 +010059 .read = &stream_sock_read,
60 .write = &stream_sock_write,
Emeric Bruncf20bf12010-10-22 16:06:11 +020061 .bind = uxst_bind_listener,
Willy Tarreaudabf2e22007-10-28 21:59:24 +010062 .bind_all = uxst_bind_listeners,
63 .unbind_all = uxst_unbind_listeners,
64 .enable_all = enable_all_listeners,
65 .disable_all = disable_all_listeners,
66 .listeners = LIST_HEAD_INIT(proto_unix.listeners),
67 .nb_listeners = 0,
68};
69
Willy Tarreaudabf2e22007-10-28 21:59:24 +010070/********************************
71 * 1) low-level socket functions
72 ********************************/
73
74
Cyril Bonté1f5848a2010-11-14 17:03:19 +010075/* Tries to destroy the UNIX stream socket <path>. The socket must not be used
76 * anymore. It practises best effort, and no error is returned.
77 */
78static void destroy_uxst_socket(const char *path)
79{
80 struct sockaddr_un addr;
81 int sock, ret;
82
83 /* We might have been chrooted, so we may not be able to access the
84 * socket. In order to avoid bothering the other end, we connect with a
85 * wrong protocol, namely SOCK_DGRAM. The return code from connect()
86 * is enough to know if the socket is still live or not. If it's live
87 * in mode SOCK_STREAM, we get EPROTOTYPE or anything else but not
88 * ECONNREFUSED. In this case, we do not touch it because it's used
89 * by some other process.
90 */
91 sock = socket(PF_UNIX, SOCK_DGRAM, 0);
92 if (sock < 0)
93 return;
94
95 addr.sun_family = AF_UNIX;
96 strncpy(addr.sun_path, path, sizeof(addr.sun_path));
97 addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
98 ret = connect(sock, (struct sockaddr *)&addr, sizeof(addr));
99 if (ret < 0 && errno == ECONNREFUSED) {
100 /* Connect failed: the socket still exists but is not used
101 * anymore. Let's remove this socket now.
102 */
103 unlink(path);
104 }
105 close(sock);
106}
107
108
109/********************************
110 * 2) listener-oriented functions
111 ********************************/
112
113
114/* This function creates a UNIX socket associated to the listener. It changes
115 * the state from ASSIGNED to LISTEN. The socket is NOT enabled for polling.
116 * The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
Willy Tarreau92fb9832007-10-16 17:34:28 +0200117 */
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100118static int uxst_bind_listener(struct listener *listener, char *errmsg, int errlen)
Willy Tarreau92fb9832007-10-16 17:34:28 +0200119{
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100120 int fd;
Willy Tarreau92fb9832007-10-16 17:34:28 +0200121 char tempname[MAXPATHLEN];
122 char backname[MAXPATHLEN];
123 struct sockaddr_un addr;
Willy Tarreaub40dc942010-11-07 12:10:51 +0100124 const char *msg = NULL;
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100125 const char *path;
126
127 int ret;
Willy Tarreau92fb9832007-10-16 17:34:28 +0200128
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100129 /* ensure we never return garbage */
130 if (errmsg && errlen)
131 *errmsg = 0;
132
133 if (listener->state != LI_ASSIGNED)
134 return ERR_NONE; /* already bound */
135
136 path = ((struct sockaddr_un *)&listener->addr)->sun_path;
Willy Tarreau92fb9832007-10-16 17:34:28 +0200137
138 /* 1. create socket names */
139 if (!path[0]) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100140 msg = "Invalid empty name for a UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200141 goto err_return;
142 }
143
144 ret = snprintf(tempname, MAXPATHLEN, "%s.%d.tmp", path, pid);
145 if (ret < 0 || ret >= MAXPATHLEN) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100146 msg = "name too long for UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200147 goto err_return;
148 }
149
150 ret = snprintf(backname, MAXPATHLEN, "%s.%d.bak", path, pid);
151 if (ret < 0 || ret >= MAXPATHLEN) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100152 msg = "name too long for UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200153 goto err_return;
154 }
155
156 /* 2. clean existing orphaned entries */
157 if (unlink(tempname) < 0 && errno != ENOENT) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100158 msg = "error when trying to unlink previous UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200159 goto err_return;
160 }
161
162 if (unlink(backname) < 0 && errno != ENOENT) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100163 msg = "error when trying to unlink previous UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200164 goto err_return;
165 }
166
167 /* 3. backup existing socket */
168 if (link(path, backname) < 0 && errno != ENOENT) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100169 msg = "error when trying to preserve previous UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200170 goto err_return;
171 }
172
173 /* 4. prepare new socket */
174 addr.sun_family = AF_UNIX;
175 strncpy(addr.sun_path, tempname, sizeof(addr.sun_path));
176 addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
177
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100178 fd = socket(PF_UNIX, SOCK_STREAM, 0);
179 if (fd < 0) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100180 msg = "cannot create UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200181 goto err_unlink_back;
182 }
183
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100184 if (fd >= global.maxsock) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100185 msg = "socket(): not enough free sockets, raise -n argument";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200186 goto err_unlink_temp;
187 }
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100188
189 if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100190 msg = "cannot make UNIX socket non-blocking";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200191 goto err_unlink_temp;
192 }
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100193
194 if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
Willy Tarreau92fb9832007-10-16 17:34:28 +0200195 /* note that bind() creates the socket <tempname> on the file system */
Willy Tarreaub40dc942010-11-07 12:10:51 +0100196 msg = "cannot bind UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200197 goto err_unlink_temp;
198 }
199
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100200 /* <uid> and <gid> different of -1 will be used to change the socket owner.
201 * If <mode> is not 0, it will be used to restrict access to the socket.
202 * While it is known not to be portable on every OS, it's still useful
203 * where it works.
204 */
205 if (((listener->perm.ux.uid != -1 || listener->perm.ux.gid != -1) &&
206 (chown(tempname, listener->perm.ux.uid, listener->perm.ux.gid) == -1)) ||
207 (listener->perm.ux.mode != 0 && chmod(tempname, listener->perm.ux.mode) == -1)) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100208 msg = "cannot change UNIX socket ownership";
Willy Tarreaue6ad2b12007-10-18 12:45:54 +0200209 goto err_unlink_temp;
210 }
211
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100212 if (listen(fd, listener->backlog ? listener->backlog : listener->maxconn) < 0) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100213 msg = "cannot listen to UNIX socket";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200214 goto err_unlink_temp;
215 }
216
217 /* 5. install.
218 * Point of no return: we are ready, we'll switch the sockets. We don't
219 * fear loosing the socket <path> because we have a copy of it in
220 * backname.
221 */
222 if (rename(tempname, path) < 0) {
Willy Tarreaub40dc942010-11-07 12:10:51 +0100223 msg = "cannot switch final and temporary UNIX sockets";
Willy Tarreau92fb9832007-10-16 17:34:28 +0200224 goto err_rename;
225 }
226
227 /* 6. cleanup */
228 unlink(backname); /* no need to keep this one either */
229
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100230 /* the socket is now listening */
231 listener->fd = fd;
232 listener->state = LI_LISTEN;
233
234 /* the function for the accept() event */
235 fd_insert(fd);
Willy Tarreaueb472682010-05-28 18:46:57 +0200236 fdtab[fd].cb[DIR_RD].f = listener->proto->accept;
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100237 fdtab[fd].cb[DIR_WR].f = NULL; /* never called */
238 fdtab[fd].cb[DIR_RD].b = fdtab[fd].cb[DIR_WR].b = NULL;
Willy Tarreaueabf3132008-08-29 23:36:51 +0200239 fdtab[fd].owner = listener; /* reference the listener instead of a task */
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100240 fdtab[fd].state = FD_STLISTEN;
Willy Tarreau8d5d77e2009-10-18 07:25:52 +0200241 fdinfo[fd].peeraddr = NULL;
242 fdinfo[fd].peerlen = 0;
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100243 return ERR_NONE;
Cyril Bonté1f5848a2010-11-14 17:03:19 +0100244 err_rename:
245 ret = rename(backname, path);
246 if (ret < 0 && errno == ENOENT)
247 unlink(path);
248 err_unlink_temp:
249 unlink(tempname);
250 close(fd);
251 err_unlink_back:
252 unlink(backname);
253 err_return:
254 if (msg && errlen)
255 snprintf(errmsg, errlen, "%s [%s]", msg, path);
256 return ERR_FATAL | ERR_ALERT;
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100257}
258
259/* This function closes the UNIX sockets for the specified listener.
260 * The listener enters the LI_ASSIGNED state. It always returns ERR_NONE.
261 */
262static int uxst_unbind_listener(struct listener *listener)
263{
264 if (listener->state == LI_READY)
265 EV_FD_CLR(listener->fd, DIR_RD);
266
267 if (listener->state >= LI_LISTEN) {
Willy Tarreau8eebe5e2007-10-28 22:07:08 +0100268 fd_delete(listener->fd);
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100269 listener->state = LI_ASSIGNED;
270 destroy_uxst_socket(((struct sockaddr_un *)&listener->addr)->sun_path);
271 }
272 return ERR_NONE;
273}
274
275/* Add a listener to the list of unix stream listeners. The listener's state
276 * is automatically updated from LI_INIT to LI_ASSIGNED. The number of
277 * listeners is updated. This is the function to use to add a new listener.
278 */
279void uxst_add_listener(struct listener *listener)
280{
281 if (listener->state != LI_INIT)
282 return;
283 listener->state = LI_ASSIGNED;
284 listener->proto = &proto_unix;
285 LIST_ADDQ(&proto_unix.listeners, &listener->proto_list);
286 proto_unix.nb_listeners++;
287}
288
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100289/********************************
290 * 3) protocol-oriented functions
291 ********************************/
292
293
Willy Tarreau92fb9832007-10-16 17:34:28 +0200294/* This function creates all UNIX sockets bound to the protocol entry <proto>.
295 * It is intended to be used as the protocol's bind_all() function.
296 * The sockets will be registered but not added to any fd_set, in order not to
297 * loose them across the fork(). A call to uxst_enable_listeners() is needed
298 * to complete initialization.
299 *
300 * The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
301 */
Emeric Bruncf20bf12010-10-22 16:06:11 +0200302static int uxst_bind_listeners(struct protocol *proto, char *errmsg, int errlen)
Willy Tarreau92fb9832007-10-16 17:34:28 +0200303{
304 struct listener *listener;
305 int err = ERR_NONE;
Willy Tarreau92fb9832007-10-16 17:34:28 +0200306
307 list_for_each_entry(listener, &proto->listeners, proto_list) {
Emeric Bruncf20bf12010-10-22 16:06:11 +0200308 err |= uxst_bind_listener(listener, errmsg, errlen);
309 if (err & ERR_ABORT)
310 break;
Willy Tarreau92fb9832007-10-16 17:34:28 +0200311 }
Willy Tarreau92fb9832007-10-16 17:34:28 +0200312 return err;
313}
314
Willy Tarreau92fb9832007-10-16 17:34:28 +0200315
316/* This function stops all listening UNIX sockets bound to the protocol
317 * <proto>. It does not detaches them from the protocol.
318 * It always returns ERR_NONE.
319 */
320static int uxst_unbind_listeners(struct protocol *proto)
321{
322 struct listener *listener;
323
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100324 list_for_each_entry(listener, &proto->listeners, proto_list)
325 uxst_unbind_listener(listener);
Willy Tarreau92fb9832007-10-16 17:34:28 +0200326 return ERR_NONE;
327}
328
Willy Tarreaudabf2e22007-10-28 21:59:24 +0100329
330/********************************
331 * 4) high-level functions
332 ********************************/
333
Willy Tarreau92fb9832007-10-16 17:34:28 +0200334__attribute__((constructor))
335static void __uxst_protocol_init(void)
336{
337 protocol_register(&proto_unix);
Willy Tarreau92fb9832007-10-16 17:34:28 +0200338}
339
340
341/*
342 * Local variables:
343 * c-indent-level: 8
344 * c-basic-offset: 8
345 * End:
346 */