2 Socket wrapper library. Passes all socket communication over
3 unix domain sockets if the environment variable SOCKET_WRAPPER_DIR
5 Copyright (C) Jelmer Vernooij 2005
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 #ifdef SOCKET_WRAPPER_REPLACE
38 /* LD_PRELOAD doesn't work yet, so REWRITE_CALLS is all we support
43 #define real_accept accept
44 #define real_connect connect
45 #define real_bind bind
46 #define real_getpeername getpeername
47 #define real_getsockname getsockname
48 #define real_getsockopt getsockopt
49 #define real_setsockopt setsockopt
50 #define real_recvfrom recvfrom
51 #define real_sendto sendto
52 #define real_socket socket
53 #define real_close close
59 /* we need to use a very terse format here as IRIX 6.4 silently
60 truncates names to 16 chars, so if we use a longer name then we
61 can't tell which port a packet came from with recvfrom()
63 with this format we have 8 chars left for the directory name
65 #define SOCKET_FORMAT "%u_%u"
67 static struct sockaddr *sockaddr_dup(const void *data, socklen_t len)
69 struct sockaddr *ret = (struct sockaddr *)malloc(len);
70 memcpy(ret, data, len);
86 struct sockaddr *myname;
89 struct sockaddr *peername;
90 socklen_t peername_len;
92 struct socket_info *prev, *next;
95 static struct socket_info *sockets = NULL;
98 static const char *socket_wrapper_dir(void)
100 const char *s = getenv("SOCKET_WRAPPER_DIR");
104 if (strncmp(s, "./", 2) == 0) {
110 static int convert_un_in(const struct sockaddr_un *un, struct sockaddr_in *in, socklen_t *len)
116 if ((*len) < sizeof(struct sockaddr_in)) {
120 in->sin_family = AF_INET;
121 in->sin_port = htons(1025); /* Default to 1025 */
122 p = strrchr(un->sun_path, '/');
123 if (p) p++; else p = un->sun_path;
125 if (sscanf(p, SOCKET_FORMAT, &type, &prt) == 2) {
126 in->sin_port = htons(prt);
128 in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
129 *len = sizeof(struct sockaddr_in);
133 static int convert_in_un(struct socket_info *si, const struct sockaddr_in *in, struct sockaddr_un *un)
136 uint16_t prt = ntohs(in->sin_port);
139 /* handle auto-allocation of ephemeral ports */
142 snprintf(un->sun_path, sizeof(un->sun_path), "%s/"SOCKET_FORMAT,
143 socket_wrapper_dir(), type, ++prt);
144 } while (stat(un->sun_path, &st) == 0 && prt < 10000);
145 ((struct sockaddr_in *)si->myname)->sin_port = htons(prt);
147 snprintf(un->sun_path, sizeof(un->sun_path), "%s/"SOCKET_FORMAT,
148 socket_wrapper_dir(), type, prt);
152 static struct socket_info *find_socket_info(int fd)
154 struct socket_info *i;
155 for (i = sockets; i; i = i->next) {
163 static int sockaddr_convert_to_un(struct socket_info *si, const struct sockaddr *in_addr, socklen_t in_len,
164 struct sockaddr_un *out_addr)
169 out_addr->sun_family = AF_UNIX;
171 switch (in_addr->sa_family) {
173 return convert_in_un(si, (const struct sockaddr_in *)in_addr, out_addr);
175 memcpy(out_addr, in_addr, sizeof(*out_addr));
181 errno = EAFNOSUPPORT;
185 static int sockaddr_convert_from_un(const struct socket_info *si,
186 const struct sockaddr_un *in_addr,
187 socklen_t un_addrlen,
189 struct sockaddr *out_addr,
192 if (out_addr == NULL || out_len == NULL)
195 if (un_addrlen == 0) {
202 return convert_un_in(in_addr, (struct sockaddr_in *)out_addr, out_len);
204 memcpy(out_addr, in_addr, sizeof(*in_addr));
205 *out_len = sizeof(*in_addr);
211 errno = EAFNOSUPPORT;
215 int swrap_socket(int domain, int type, int protocol)
217 struct socket_info *si;
220 if (!socket_wrapper_dir()) {
221 return real_socket(domain, type, protocol);
224 fd = real_socket(AF_UNIX, type, 0);
226 if (fd == -1) return -1;
228 si = calloc(1, sizeof(struct socket_info));
232 si->protocol = protocol;
235 DLIST_ADD(sockets, si);
240 int swrap_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
242 struct socket_info *parent_si, *child_si;
244 socklen_t un_addrlen = sizeof(struct sockaddr_un);
245 struct sockaddr_un un_addr;
248 parent_si = find_socket_info(s);
250 return real_accept(s, addr, addrlen);
253 memset(&un_addr, 0, sizeof(un_addr));
255 ret = real_accept(s, (struct sockaddr *)&un_addr, &un_addrlen);
256 if (ret == -1) return ret;
260 ret = sockaddr_convert_from_un(parent_si, &un_addr, un_addrlen,
261 parent_si->domain, addr, addrlen);
262 if (ret == -1) return ret;
264 child_si = malloc(sizeof(struct socket_info));
265 memset(child_si, 0, sizeof(*child_si));
270 child_si->myname_len = parent_si->myname_len;
271 child_si->myname = sockaddr_dup(parent_si->myname, parent_si->myname_len);
273 child_si->peername_len = *addrlen;
274 child_si->peername = sockaddr_dup(addr, *addrlen);
276 DLIST_ADD(sockets, child_si);
281 /* using sendto() or connect() on an unbound socket would give the
282 recipient no way to reply, as unlike UDP and TCP, a unix domain
283 socket can't auto-assign emphemeral port numbers, so we need to
285 static int swrap_auto_bind(struct socket_info *si)
287 struct sockaddr_un un_addr;
288 struct sockaddr_in in;
291 un_addr.sun_family = AF_UNIX;
293 for (i=0;i<1000;i++) {
294 snprintf(un_addr.sun_path, sizeof(un_addr.sun_path),
295 "%s/"SOCKET_FORMAT, socket_wrapper_dir(),
296 SOCK_DGRAM, i + 10000);
297 if (bind(si->fd, (struct sockaddr *)&un_addr,
298 sizeof(un_addr)) == 0) {
299 si->tmp_path = strdup(un_addr.sun_path);
308 memset(&in, 0, sizeof(in));
309 in.sin_family = AF_INET;
310 in.sin_port = htons(i);
311 in.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
313 si->myname_len = sizeof(in);
314 si->myname = sockaddr_dup(&in, si->myname_len);
320 int swrap_connect(int s, const struct sockaddr *serv_addr, socklen_t addrlen)
323 struct sockaddr_un un_addr;
324 struct socket_info *si = find_socket_info(s);
327 return real_connect(s, serv_addr, addrlen);
330 /* only allow pseudo loopback connections */
331 if (serv_addr->sa_family == AF_INET &&
332 ((const struct sockaddr_in *)serv_addr)->sin_addr.s_addr !=
333 htonl(INADDR_LOOPBACK)) {
338 if (si->bound == 0 && si->domain != AF_UNIX) {
339 ret = swrap_auto_bind(si);
340 if (ret == -1) return -1;
343 ret = sockaddr_convert_to_un(si, (const struct sockaddr *)serv_addr, addrlen, &un_addr);
344 if (ret == -1) return -1;
346 ret = real_connect(s, (struct sockaddr *)&un_addr,
347 sizeof(struct sockaddr_un));
350 si->peername_len = addrlen;
351 si->peername = sockaddr_dup(serv_addr, addrlen);
357 int swrap_bind(int s, const struct sockaddr *myaddr, socklen_t addrlen)
360 struct sockaddr_un un_addr;
361 struct socket_info *si = find_socket_info(s);
364 return real_bind(s, myaddr, addrlen);
367 si->myname_len = addrlen;
368 si->myname = sockaddr_dup(myaddr, addrlen);
370 if (myaddr->sa_family == AF_INET &&
371 ((const struct sockaddr_in *)myaddr)->sin_addr.s_addr == 0) {
372 ((struct sockaddr_in *)si->myname)->sin_addr.s_addr =
373 htonl(INADDR_LOOPBACK);
375 ret = sockaddr_convert_to_un(si, (const struct sockaddr *)myaddr, addrlen, &un_addr);
376 if (ret == -1) return -1;
378 unlink(un_addr.sun_path);
380 ret = real_bind(s, (struct sockaddr *)&un_addr,
381 sizeof(struct sockaddr_un));
390 int swrap_getpeername(int s, struct sockaddr *name, socklen_t *addrlen)
392 struct socket_info *si = find_socket_info(s);
395 return real_getpeername(s, name, addrlen);
404 memcpy(name, si->peername, si->peername_len);
405 *addrlen = si->peername_len;
410 int swrap_getsockname(int s, struct sockaddr *name, socklen_t *addrlen)
412 struct socket_info *si = find_socket_info(s);
415 return real_getsockname(s, name, addrlen);
418 memcpy(name, si->myname, si->myname_len);
419 *addrlen = si->myname_len;
424 int swrap_getsockopt(int s, int level, int optname, void *optval, socklen_t *optlen)
426 struct socket_info *si = find_socket_info(s);
429 return real_getsockopt(s, level, optname, optval, optlen);
432 if (level == SOL_SOCKET) {
433 return real_getsockopt(s, level, optname, optval, optlen);
436 switch (si->domain) {
438 return real_getsockopt(s, level, optname, optval, optlen);
445 int swrap_setsockopt(int s, int level, int optname, const void *optval, socklen_t optlen)
447 struct socket_info *si = find_socket_info(s);
450 return real_setsockopt(s, level, optname, optval, optlen);
453 if (level == SOL_SOCKET) {
454 return real_setsockopt(s, level, optname, optval, optlen);
457 switch (si->domain) {
459 return real_setsockopt(s, level, optname, optval, optlen);
461 /* Silence some warnings */
463 if (optname == TCP_NODELAY)
472 ssize_t swrap_recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlen)
474 struct sockaddr_un un_addr;
475 socklen_t un_addrlen = sizeof(un_addr);
477 struct socket_info *si = find_socket_info(s);
480 return real_recvfrom(s, buf, len, flags, from, fromlen);
483 /* irix 6.4 forgets to null terminate the sun_path string :-( */
484 memset(&un_addr, 0, sizeof(un_addr));
485 ret = real_recvfrom(s, buf, len, flags, (struct sockaddr *)&un_addr, &un_addrlen);
489 if (sockaddr_convert_from_un(si, &un_addr, un_addrlen,
490 si->domain, from, fromlen) == -1) {
498 ssize_t swrap_sendto(int s, const void *buf, size_t len, int flags, const struct sockaddr *to, socklen_t tolen)
500 struct sockaddr_un un_addr;
502 struct socket_info *si = find_socket_info(s);
505 return real_sendto(s, buf, len, flags, to, tolen);
508 if (si->bound == 0 && si->domain != AF_UNIX) {
509 ret = swrap_auto_bind(si);
510 if (ret == -1) return -1;
513 ret = sockaddr_convert_to_un(si, to, tolen, &un_addr);
514 if (ret == -1) return -1;
516 ret = real_sendto(s, buf, len, flags, (struct sockaddr *)&un_addr, sizeof(un_addr));
521 int swrap_close(int fd)
523 struct socket_info *si = find_socket_info(fd);
526 DLIST_REMOVE(sockets, si);
532 unlink(si->tmp_path);
538 return real_close(fd);