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,
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.
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)
167 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
171 * Check for special cases where we need to do something
172 * other than test arg[0].
175 if (s->sys_func == sys_dup2 ||
176 s->sys_func == sys_dup3 ||
177 s->sys_func == sys_sendfile ||
178 s->sys_func == sys_sendfile64 ||
179 s->sys_func == sys_tee)
182 return fdmatch(tcp, tcp->u_arg[0]) ||
183 fdmatch(tcp, tcp->u_arg[1]);
186 if (s->sys_func == sys_inotify_add_watch ||
187 s->sys_func == sys_faccessat ||
188 s->sys_func == sys_fchmodat ||
189 s->sys_func == sys_futimesat ||
190 s->sys_func == sys_mkdirat ||
191 s->sys_func == sys_unlinkat ||
192 s->sys_func == sys_newfstatat ||
193 s->sys_func == sys_mknodat ||
194 s->sys_func == sys_openat ||
195 s->sys_func == sys_readlinkat ||
196 s->sys_func == sys_utimensat ||
197 s->sys_func == sys_fchownat ||
198 s->sys_func == sys_pipe2)
201 return fdmatch(tcp, tcp->u_arg[0]) ||
202 upathmatch(tcp, tcp->u_arg[1]);
205 if (s->sys_func == sys_link ||
206 s->sys_func == sys_mount)
209 return upathmatch(tcp, tcp->u_arg[0]) ||
210 upathmatch(tcp, tcp->u_arg[1]);
213 if (s->sys_func == sys_quotactl)
216 return upathmatch(tcp, tcp->u_arg[1]);
219 if (s->sys_func == sys_renameat ||
220 s->sys_func == sys_linkat)
222 /* fd, path, fd, path */
223 return fdmatch(tcp, tcp->u_arg[0]) ||
224 fdmatch(tcp, tcp->u_arg[2]) ||
225 upathmatch(tcp, tcp->u_arg[1]) ||
226 upathmatch(tcp, tcp->u_arg[3]);
230 s->sys_func == sys_old_mmap ||
232 s->sys_func == sys_old_mmap_pgoff ||
234 s->sys_func == sys_mmap ||
235 s->sys_func == sys_mmap_pgoff ||
236 s->sys_func == sys_mmap_4koff
239 return fdmatch(tcp, tcp->u_arg[4]);
242 if (s->sys_func == sys_symlinkat) {
244 return fdmatch(tcp, tcp->u_arg[1]) ||
245 upathmatch(tcp, tcp->u_arg[0]) ||
246 upathmatch(tcp, tcp->u_arg[2]);
249 if (s->sys_func == sys_splice) {
250 /* fd, x, fd, x, x */
251 return fdmatch(tcp, tcp->u_arg[0]) ||
252 fdmatch(tcp, tcp->u_arg[2]);
255 if (s->sys_func == sys_epoll_ctl) {
257 return fdmatch(tcp, tcp->u_arg[2]);
260 if (s->sys_func == sys_select ||
261 s->sys_func == sys_oldselect ||
262 s->sys_func == sys_pselect6)
266 long *args, oldargs[5];
270 if (s->sys_func == sys_oldselect) {
271 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
272 (char*) oldargs) < 0)
274 fprintf(stderr, "umoven() failed\n");
282 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
283 if (args[0] > 1024*1024)
287 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
289 fds = malloc(fdsize);
293 for (i = 1; i <= 3; ++i) {
297 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
298 fprintf(stderr, "umoven() failed\n");
302 for (j = 0; j < nfds; ++j)
303 if (FD_ISSET(j, fds) && fdmatch(tcp, j)) {
312 if (s->sys_func == sys_poll ||
313 s->sys_func == sys_ppoll)
317 unsigned long start, cur, end;
319 start = tcp->u_arg[0];
320 nfds = tcp->u_arg[1];
322 end = start + sizeof(fds) * nfds;
324 if (nfds == 0 || end < start)
327 for (cur = start; cur < end; cur += sizeof(fds))
328 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
329 && fdmatch(tcp, fds.fd))
335 if (s->sys_func == printargs ||
336 s->sys_func == sys_pipe ||
337 s->sys_func == sys_pipe2 ||
338 s->sys_func == sys_eventfd2 ||
339 s->sys_func == sys_eventfd ||
340 s->sys_func == sys_inotify_init1 ||
341 s->sys_func == sys_timerfd_create ||
342 s->sys_func == sys_timerfd_settime ||
343 s->sys_func == sys_timerfd_gettime ||
344 s->sys_func == sys_epoll_create ||
345 strcmp(s->sys_name, "fanotify_init") == 0)
348 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
349 * don't have any file descriptor or path args to test.
355 * Our fallback position for calls that haven't already
356 * been handled is to just check arg[0].
359 if (s->sys_flags & TRACE_FILE)
360 return upathmatch(tcp, tcp->u_arg[0]);
362 if (s->sys_flags & TRACE_DESC)
363 return fdmatch(tcp, tcp->u_arg[0]);