blob: 28fc7c9ad8773c82c16bcc206a4514da922b6ec3 [file] [log] [blame]
Grant Edwards8a082772011-04-07 20:25:40 +00001/*
2 * Copyright (c) 2011, Comtrol Corp.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 */
28
29#include "defs.h"
Dmitry V. Levinb038a432011-08-30 16:05:26 +000030#include <sys/param.h>
Dmitry V. Levind64a7e42013-11-06 01:17:05 +000031#if defined HAVE_POLL_H
Denys Vlasenkoa6d91de2012-03-16 12:02:22 +010032# include <poll.h>
Dmitry V. Levind64a7e42013-11-06 01:17:05 +000033#elif defined HAVE_SYS_POLL_H
Denys Vlasenkoa6d91de2012-03-16 12:02:22 +010034# include <sys/poll.h>
Grant Edwards8a082772011-04-07 20:25:40 +000035#endif
36
37#include "syscall.h"
38
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010039const char **paths_selected = NULL;
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010040static unsigned num_selected = 0;
Grant Edwards8a082772011-04-07 20:25:40 +000041
42/*
43 * Return true if specified path matches one that we're tracing.
44 */
45static int
46pathmatch(const char *path)
47{
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010048 unsigned i;
Grant Edwards8a082772011-04-07 20:25:40 +000049
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010050 for (i = 0; i < num_selected; ++i) {
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010051 if (strcmp(path, paths_selected[i]) == 0)
Grant Edwards8a082772011-04-07 20:25:40 +000052 return 1;
53 }
54 return 0;
55}
56
57/*
58 * Return true if specified path (in user-space) matches.
59 */
60static int
61upathmatch(struct tcb *tcp, unsigned long upath)
62{
Denys Vlasenko7b609d52011-06-22 14:32:43 +020063 char path[PATH_MAX + 1];
Grant Edwards8a082772011-04-07 20:25:40 +000064
Dmitry V. Levin1a880cf2013-02-26 19:23:27 +000065 return umovestr(tcp, upath, sizeof path, path) > 0 &&
Grant Edwards8a082772011-04-07 20:25:40 +000066 pathmatch(path);
67}
68
69/*
70 * Return true if specified fd maps to a path we're tracing.
71 */
72static int
73fdmatch(struct tcb *tcp, int fd)
74{
Denys Vlasenko61ad0a42013-03-06 18:24:34 +010075 char path[PATH_MAX + 1];
76 int n = getfdpath(tcp, fd, path, sizeof(path));
Grant Edwards8a082772011-04-07 20:25:40 +000077
Denys Vlasenko61ad0a42013-03-06 18:24:34 +010078 return n >= 0 && pathmatch(path);
Grant Edwards8a082772011-04-07 20:25:40 +000079}
80
81/*
82 * Add a path to the set we're tracing.
Philippe Ombredanne894c7e32014-02-01 09:57:45 -080083 * Specifying NULL will delete all paths.
Grant Edwards8a082772011-04-07 20:25:40 +000084 */
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010085static void
Grant Edwards8a082772011-04-07 20:25:40 +000086storepath(const char *path)
87{
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010088 unsigned i;
Grant Edwards8a082772011-04-07 20:25:40 +000089
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010090 if (pathmatch(path))
91 return; /* already in table */
Grant Edwards8a082772011-04-07 20:25:40 +000092
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010093 i = num_selected++;
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010094 paths_selected = realloc(paths_selected, num_selected * sizeof(paths_selected[0]));
95 if (!paths_selected)
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010096 die_out_of_memory();
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010097 paths_selected[i] = path;
Grant Edwards8a082772011-04-07 20:25:40 +000098}
99
100/*
101 * Get path associated with fd.
102 */
Denys Vlasenko61ad0a42013-03-06 18:24:34 +0100103int
104getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize)
Grant Edwards8a082772011-04-07 20:25:40 +0000105{
Denys Vlasenko384b0ad2012-03-15 18:11:51 +0100106 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3];
Grant Edwards8a082772011-04-07 20:25:40 +0000107 ssize_t n;
108
109 if (fd < 0)
Denys Vlasenko61ad0a42013-03-06 18:24:34 +0100110 return -1;
Grant Edwards8a082772011-04-07 20:25:40 +0000111
Denys Vlasenko29865e72012-03-15 18:03:56 +0100112 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
Denys Vlasenko61ad0a42013-03-06 18:24:34 +0100113 n = readlink(linkpath, buf, bufsize - 1);
114 /*
115 * NB: if buf is too small, readlink doesn't fail,
116 * it returns truncated result (IOW: n == bufsize - 1).
117 */
118 if (n >= 0)
119 buf[n] = '\0';
120 return n;
Grant Edwards8a082772011-04-07 20:25:40 +0000121}
122
123/*
124 * Add a path to the set we're tracing. Also add the canonicalized
125 * version of the path. Secifying NULL will delete all paths.
126 */
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100127void
Grant Edwards8a082772011-04-07 20:25:40 +0000128pathtrace_select(const char *path)
129{
Denys Vlasenko29865e72012-03-15 18:03:56 +0100130 char *rpath;
Grant Edwards8a082772011-04-07 20:25:40 +0000131
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100132 storepath(path);
Grant Edwards8a082772011-04-07 20:25:40 +0000133
134 rpath = realpath(path, NULL);
135
136 if (rpath == NULL)
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100137 return;
Grant Edwards8a082772011-04-07 20:25:40 +0000138
139 /* if realpath and specified path are same, we're done */
Denys Vlasenko29865e72012-03-15 18:03:56 +0100140 if (strcmp(path, rpath) == 0) {
Grant Edwards8a082772011-04-07 20:25:40 +0000141 free(rpath);
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100142 return;
Grant Edwards8a082772011-04-07 20:25:40 +0000143 }
144
145 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
146 path, rpath);
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100147 storepath(rpath);
Grant Edwards8a082772011-04-07 20:25:40 +0000148}
149
150/*
151 * Return true if syscall accesses a selected path
152 * (or if no paths have been specified for tracing).
153 */
154int
155pathtrace_match(struct tcb *tcp)
156{
Denys Vlasenkoa9fe13c2013-02-22 13:26:10 +0100157 const struct_sysent *s;
Grant Edwards8a082772011-04-07 20:25:40 +0000158
Denys Vlasenko74ec14f2013-02-21 16:13:47 +0100159 s = tcp->s_ent;
Grant Edwards8a082772011-04-07 20:25:40 +0000160
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800161 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
Grant Edwards8a082772011-04-07 20:25:40 +0000162 return 0;
163
164 /*
165 * Check for special cases where we need to do something
166 * other than test arg[0].
167 */
168
Grant Edwards8a082772011-04-07 20:25:40 +0000169 if (s->sys_func == sys_dup2 ||
170 s->sys_func == sys_dup3 ||
171 s->sys_func == sys_sendfile ||
172 s->sys_func == sys_sendfile64 ||
Dmitry V. Levinad178c02011-11-28 22:48:53 +0000173 s->sys_func == sys_tee)
Grant Edwards8a082772011-04-07 20:25:40 +0000174 {
175 /* fd, fd */
176 return fdmatch(tcp, tcp->u_arg[0]) ||
177 fdmatch(tcp, tcp->u_arg[1]);
178 }
179
180 if (s->sys_func == sys_inotify_add_watch ||
181 s->sys_func == sys_faccessat ||
182 s->sys_func == sys_fchmodat ||
183 s->sys_func == sys_futimesat ||
Grant Edwards8a082772011-04-07 20:25:40 +0000184 s->sys_func == sys_unlinkat ||
185 s->sys_func == sys_newfstatat ||
186 s->sys_func == sys_mknodat ||
187 s->sys_func == sys_openat ||
188 s->sys_func == sys_readlinkat ||
189 s->sys_func == sys_utimensat ||
190 s->sys_func == sys_fchownat ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200191 s->sys_func == sys_pipe2)
Grant Edwards8a082772011-04-07 20:25:40 +0000192 {
193 /* fd, path */
194 return fdmatch(tcp, tcp->u_arg[0]) ||
195 upathmatch(tcp, tcp->u_arg[1]);
196 }
197
198 if (s->sys_func == sys_link ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200199 s->sys_func == sys_mount)
Grant Edwards8a082772011-04-07 20:25:40 +0000200 {
201 /* path, path */
202 return upathmatch(tcp, tcp->u_arg[0]) ||
203 upathmatch(tcp, tcp->u_arg[1]);
204 }
205
Dmitry V. Levin79439662012-10-26 23:43:13 +0000206 if (s->sys_func == sys_quotactl)
207 {
208 /* x, path */
209 return upathmatch(tcp, tcp->u_arg[1]);
210 }
211
Grant Edwards8a082772011-04-07 20:25:40 +0000212 if (s->sys_func == sys_renameat ||
Mike Frysinger5b677ab2014-08-14 04:05:41 -0400213 s->sys_func == sys_renameat2 ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200214 s->sys_func == sys_linkat)
Grant Edwards8a082772011-04-07 20:25:40 +0000215 {
216 /* fd, path, fd, path */
217 return fdmatch(tcp, tcp->u_arg[0]) ||
218 fdmatch(tcp, tcp->u_arg[2]) ||
219 upathmatch(tcp, tcp->u_arg[1]) ||
220 upathmatch(tcp, tcp->u_arg[3]);
221 }
222
H.J. Lu35be5812012-04-16 13:00:01 +0200223 if (
H.J. Lu35be5812012-04-16 13:00:01 +0200224 s->sys_func == sys_old_mmap ||
Denys Vlasenko1ba85432013-02-19 11:28:20 +0100225#if defined(S390)
226 s->sys_func == sys_old_mmap_pgoff ||
227#endif
228 s->sys_func == sys_mmap ||
229 s->sys_func == sys_mmap_pgoff ||
230 s->sys_func == sys_mmap_4koff
231 ) {
Grant Edwards8a082772011-04-07 20:25:40 +0000232 /* x, x, x, x, fd */
233 return fdmatch(tcp, tcp->u_arg[4]);
234 }
235
Denys Vlasenko7b609d52011-06-22 14:32:43 +0200236 if (s->sys_func == sys_symlinkat) {
Grant Edwards8a082772011-04-07 20:25:40 +0000237 /* path, fd, path */
238 return fdmatch(tcp, tcp->u_arg[1]) ||
239 upathmatch(tcp, tcp->u_arg[0]) ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200240 upathmatch(tcp, tcp->u_arg[2]);
Grant Edwards8a082772011-04-07 20:25:40 +0000241 }
242
Dmitry V. Levinad178c02011-11-28 22:48:53 +0000243 if (s->sys_func == sys_splice) {
Grant Edwards8a082772011-04-07 20:25:40 +0000244 /* fd, x, fd, x, x */
245 return fdmatch(tcp, tcp->u_arg[0]) ||
246 fdmatch(tcp, tcp->u_arg[2]);
247 }
248
Denys Vlasenko7b609d52011-06-22 14:32:43 +0200249 if (s->sys_func == sys_epoll_ctl) {
Grant Edwards8a082772011-04-07 20:25:40 +0000250 /* x, x, fd, x */
251 return fdmatch(tcp, tcp->u_arg[2]);
252 }
253
Dmitry V. Levin99db95d2014-02-05 04:13:18 +0000254 if (s->sys_func == sys_fanotify_mark) {
255 /* x, x, x, fd, path */
256 return fdmatch(tcp, tcp->u_arg[3]) ||
257 upathmatch(tcp, tcp->u_arg[4]);
258 }
259
Grant Edwards8a082772011-04-07 20:25:40 +0000260 if (s->sys_func == sys_select ||
261 s->sys_func == sys_oldselect ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200262 s->sys_func == sys_pselect6)
Grant Edwards8a082772011-04-07 20:25:40 +0000263 {
Denys Vlasenko79a79ea2011-09-01 16:35:44 +0200264 int i, j;
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100265 int nfds;
Grant Edwards8a082772011-04-07 20:25:40 +0000266 long *args, oldargs[5];
267 unsigned fdsize;
268 fd_set *fds;
269
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100270 args = tcp->u_arg;
Denys Vlasenko7b609d52011-06-22 14:32:43 +0200271 if (s->sys_func == sys_oldselect) {
Grant Edwards8a082772011-04-07 20:25:40 +0000272 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
273 (char*) oldargs) < 0)
274 {
275 fprintf(stderr, "umoven() failed\n");
276 return 0;
277 }
278 args = oldargs;
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100279 }
Grant Edwards8a082772011-04-07 20:25:40 +0000280
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100281 /* Kernel truncates arg[0] to int, we do the same. */
282 nfds = (int) args[0];
283 /* Kernel rejects negative nfds, so we don't parse it either. */
284 if (nfds <= 0)
285 return 0;
Denys Vlasenko79a79ea2011-09-01 16:35:44 +0200286 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100287 if (nfds > 1024*1024)
Denys Vlasenko79a79ea2011-09-01 16:35:44 +0200288 nfds = 1024*1024;
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100289 fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
Grant Edwards8a082772011-04-07 20:25:40 +0000290 fds = malloc(fdsize);
Denys Vlasenko1d46ba52011-08-31 14:00:02 +0200291 if (!fds)
292 die_out_of_memory();
Grant Edwards8a082772011-04-07 20:25:40 +0000293
Denys Vlasenko7b609d52011-06-22 14:32:43 +0200294 for (i = 1; i <= 3; ++i) {
Grant Edwards8a082772011-04-07 20:25:40 +0000295 if (args[i] == 0)
296 continue;
Denys Vlasenko7b609d52011-06-22 14:32:43 +0200297 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
Grant Edwards8a082772011-04-07 20:25:40 +0000298 fprintf(stderr, "umoven() failed\n");
299 continue;
300 }
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100301 for (j = 0;; j++) {
302 j = next_set_bit(fds, j, nfds);
303 if (j < 0)
304 break;
305 if (fdmatch(tcp, j)) {
Grant Edwards8a082772011-04-07 20:25:40 +0000306 free(fds);
307 return 1;
308 }
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100309 }
Grant Edwards8a082772011-04-07 20:25:40 +0000310 }
311 free(fds);
312 return 0;
313 }
314
315 if (s->sys_func == sys_poll ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200316 s->sys_func == sys_ppoll)
Grant Edwards8a082772011-04-07 20:25:40 +0000317 {
318 struct pollfd fds;
319 unsigned nfds;
320 unsigned long start, cur, end;
321
322 start = tcp->u_arg[0];
323 nfds = tcp->u_arg[1];
324
325 end = start + sizeof(fds) * nfds;
326
327 if (nfds == 0 || end < start)
328 return 0;
329
330 for (cur = start; cur < end; cur += sizeof(fds))
331 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
332 && fdmatch(tcp, fds.fd))
333 return 1;
334
335 return 0;
336 }
337
338 if (s->sys_func == printargs ||
339 s->sys_func == sys_pipe ||
340 s->sys_func == sys_pipe2 ||
341 s->sys_func == sys_eventfd2 ||
342 s->sys_func == sys_eventfd ||
343 s->sys_func == sys_inotify_init1 ||
344 s->sys_func == sys_timerfd_create ||
345 s->sys_func == sys_timerfd_settime ||
346 s->sys_func == sys_timerfd_gettime ||
347 s->sys_func == sys_epoll_create ||
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800348 s->sys_func == sys_socket ||
349 s->sys_func == sys_socketpair ||
Dmitry V. Levin99db95d2014-02-05 04:13:18 +0000350 s->sys_func == sys_fanotify_init)
Grant Edwards8a082772011-04-07 20:25:40 +0000351 {
352 /*
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800353 * These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set,
354 * but they don't have any file descriptor or path args to test.
Grant Edwards8a082772011-04-07 20:25:40 +0000355 */
356 return 0;
357 }
Grant Edwards8a082772011-04-07 20:25:40 +0000358
359 /*
360 * Our fallback position for calls that haven't already
361 * been handled is to just check arg[0].
362 */
363
364 if (s->sys_flags & TRACE_FILE)
365 return upathmatch(tcp, tcp->u_arg[0]);
366
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800367 if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK))
Grant Edwards8a082772011-04-07 20:25:40 +0000368 return fdmatch(tcp, tcp->u_arg[0]);
369
370 return 0;
371}