2 * Copyright (c) 2011, Comtrol Corp.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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,
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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.
30 #include <sys/param.h>
34 #ifdef HAVE_SYS_POLL_H
35 # include <sys/poll.h>
40 #define MAXSELECTED 256 /* max number of "selected" paths */
41 static const char *selected[MAXSELECTED]; /* paths selected for tracing */
44 * Return true if specified path matches one that we're tracing.
47 pathmatch(const char *path)
51 for (i = 0; i < ARRAY_SIZE(selected); ++i) {
52 if (selected[i] == NULL)
54 if (strcmp(path, selected[i]) == 0)
61 * Return true if specified path (in user-space) matches.
64 upathmatch(struct tcb *tcp, unsigned long upath)
66 char path[PATH_MAX + 1];
68 return umovestr(tcp, upath, sizeof path, path) >= 0 &&
73 * Return true if specified fd maps to a path we're tracing.
76 fdmatch(struct tcb *tcp, int fd)
78 const char *path = getfdpath(tcp, fd);
80 return path && pathmatch(path);
84 * Add a path to the set we're tracing.
85 * Secifying NULL will delete all paths.
88 storepath(const char *path)
92 for (i = 0; i < ARRAY_SIZE(selected); ++i) {
99 fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
100 (unsigned int) ARRAY_SIZE(selected));
105 * Get path associated with fd.
108 getfdpath(struct tcb *tcp, int fd)
110 static char path[PATH_MAX+1];
111 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3];
117 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
118 n = readlink(linkpath, path, (sizeof path) - 1);
126 * Add a path to the set we're tracing. Also add the canonicalized
127 * version of the path. Secifying NULL will delete all paths.
130 pathtrace_select(const char *path)
137 rpath = realpath(path, NULL);
142 /* if realpath and specified path are same, we're done */
143 if (strcmp(path, rpath) == 0) {
148 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
150 return storepath(rpath);
154 * Return true if syscall accesses a selected path
155 * (or if no paths have been specified for tracing).
158 pathtrace_match(struct tcb *tcp)
160 const struct sysent *s;
162 if (selected[0] == NULL)
165 if (!SCNO_IN_RANGE(tcp->scno))
168 s = &sysent[tcp->scno];
170 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
174 * Check for special cases where we need to do something
175 * other than test arg[0].
178 if (s->sys_func == sys_dup2 ||
179 s->sys_func == sys_dup3 ||
180 s->sys_func == sys_sendfile ||
181 s->sys_func == sys_sendfile64 ||
182 s->sys_func == sys_tee)
185 return fdmatch(tcp, tcp->u_arg[0]) ||
186 fdmatch(tcp, tcp->u_arg[1]);
189 if (s->sys_func == sys_inotify_add_watch ||
190 s->sys_func == sys_faccessat ||
191 s->sys_func == sys_fchmodat ||
192 s->sys_func == sys_futimesat ||
193 s->sys_func == sys_mkdirat ||
194 s->sys_func == sys_unlinkat ||
195 s->sys_func == sys_newfstatat ||
196 s->sys_func == sys_mknodat ||
197 s->sys_func == sys_openat ||
198 s->sys_func == sys_readlinkat ||
199 s->sys_func == sys_utimensat ||
200 s->sys_func == sys_fchownat ||
201 s->sys_func == sys_pipe2)
204 return fdmatch(tcp, tcp->u_arg[0]) ||
205 upathmatch(tcp, tcp->u_arg[1]);
208 if (s->sys_func == sys_link ||
209 s->sys_func == sys_mount)
212 return upathmatch(tcp, tcp->u_arg[0]) ||
213 upathmatch(tcp, tcp->u_arg[1]);
216 if (s->sys_func == sys_renameat ||
217 s->sys_func == sys_linkat)
219 /* fd, path, fd, path */
220 return fdmatch(tcp, tcp->u_arg[0]) ||
221 fdmatch(tcp, tcp->u_arg[2]) ||
222 upathmatch(tcp, tcp->u_arg[1]) ||
223 upathmatch(tcp, tcp->u_arg[3]);
228 s->sys_func == sys_old_mmap ||
230 s->sys_func == sys_mmap) {
232 return fdmatch(tcp, tcp->u_arg[4]);
235 if (s->sys_func == sys_symlinkat) {
237 return fdmatch(tcp, tcp->u_arg[1]) ||
238 upathmatch(tcp, tcp->u_arg[0]) ||
239 upathmatch(tcp, tcp->u_arg[2]);
242 if (s->sys_func == sys_splice) {
243 /* fd, x, fd, x, x */
244 return fdmatch(tcp, tcp->u_arg[0]) ||
245 fdmatch(tcp, tcp->u_arg[2]);
248 if (s->sys_func == sys_epoll_ctl) {
250 return fdmatch(tcp, tcp->u_arg[2]);
253 if (s->sys_func == sys_select ||
254 s->sys_func == sys_oldselect ||
255 s->sys_func == sys_pselect6)
259 long *args, oldargs[5];
263 if (s->sys_func == sys_oldselect) {
264 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
265 (char*) oldargs) < 0)
267 fprintf(stderr, "umoven() failed\n");
275 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
276 if (args[0] > 1024*1024)
280 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
282 fds = malloc(fdsize);
286 for (i = 1; i <= 3; ++i) {
290 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
291 fprintf(stderr, "umoven() failed\n");
295 for (j = 0; j < nfds; ++j)
296 if (FD_ISSET(j, fds) && fdmatch(tcp, j)) {
305 if (s->sys_func == sys_poll ||
306 s->sys_func == sys_ppoll)
310 unsigned long start, cur, end;
312 start = tcp->u_arg[0];
313 nfds = tcp->u_arg[1];
315 end = start + sizeof(fds) * nfds;
317 if (nfds == 0 || end < start)
320 for (cur = start; cur < end; cur += sizeof(fds))
321 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
322 && fdmatch(tcp, fds.fd))
328 if (s->sys_func == printargs ||
329 s->sys_func == sys_pipe ||
330 s->sys_func == sys_pipe2 ||
331 s->sys_func == sys_eventfd2 ||
332 s->sys_func == sys_eventfd ||
333 s->sys_func == sys_inotify_init1 ||
334 s->sys_func == sys_timerfd_create ||
335 s->sys_func == sys_timerfd_settime ||
336 s->sys_func == sys_timerfd_gettime ||
337 s->sys_func == sys_epoll_create ||
338 strcmp(s->sys_name, "fanotify_init") == 0)
341 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
342 * don't have any file descriptor or path args to test.
348 * Our fallback position for calls that haven't already
349 * been handled is to just check arg[0].
352 if (s->sys_flags & TRACE_FILE)
353 return upathmatch(tcp, tcp->u_arg[0]);
355 if (s->sys_flags & TRACE_DESC)
356 return fdmatch(tcp, tcp->u_arg[0]);