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.
32 #include <sys/param.h>
37 #ifdef HAVE_SYS_POLL_H
43 #define MAXSELECTED 256 /* max number of "selected" paths */
44 static const char *selected[MAXSELECTED]; /* paths selected for tracing */
47 * Return true if specified path matches one that we're tracing.
50 pathmatch(const char *path)
54 for (i = 0; i < ARRAY_SIZE(selected); ++i) {
55 if (selected[i] == NULL)
57 if (!strcmp(path, selected[i]))
64 * Return true if specified path (in user-space) matches.
67 upathmatch(struct tcb *tcp, unsigned long upath)
69 char path[PATH_MAX + 1];
71 return umovestr(tcp, upath, sizeof path, path) >= 0 &&
76 * Return true if specified fd maps to a path we're tracing.
79 fdmatch(struct tcb *tcp, int fd)
81 const char *path = getfdpath(tcp, fd);
83 return path && pathmatch(path);
87 * Add a path to the set we're tracing.
88 * Secifying NULL will delete all paths.
91 storepath(const char *path)
96 for (i = 0; i < ARRAY_SIZE(selected); ++i)
98 free((char *) selected[i]);
104 for (i = 0; i < ARRAY_SIZE(selected); ++i)
110 fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
111 (unsigned int) ARRAY_SIZE(selected));
116 * Get path associated with fd.
118 const char *getfdpath(struct tcb *tcp, int fd)
120 static char path[PATH_MAX+1];
127 snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
128 n = readlink(linkpath, path, (sizeof path) - 1);
136 * Add a path to the set we're tracing. Also add the canonicalized
137 * version of the path. Secifying NULL will delete all paths.
140 pathtrace_select(const char *path)
145 return storepath(path);
150 rpath = realpath(path, NULL);
155 /* if realpath and specified path are same, we're done */
156 if (!strcmp(path, rpath)) {
161 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
163 return storepath(rpath);
167 * Return true if syscall accesses a selected path
168 * (or if no paths have been specified for tracing).
171 pathtrace_match(struct tcb *tcp)
173 const struct sysent *s;
175 if (selected[0] == NULL)
178 if (!SCNO_IN_RANGE(tcp->scno))
181 s = &sysent[tcp->scno];
183 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
187 * Check for special cases where we need to do something
188 * other than test arg[0].
191 if (s->sys_func == sys_dup2 ||
192 s->sys_func == sys_dup3 ||
193 s->sys_func == sys_sendfile ||
194 s->sys_func == sys_sendfile64 ||
195 s->sys_func == sys_tee)
198 return fdmatch(tcp, tcp->u_arg[0]) ||
199 fdmatch(tcp, tcp->u_arg[1]);
202 if (s->sys_func == sys_inotify_add_watch ||
203 s->sys_func == sys_faccessat ||
204 s->sys_func == sys_fchmodat ||
205 s->sys_func == sys_futimesat ||
206 s->sys_func == sys_mkdirat ||
207 s->sys_func == sys_unlinkat ||
208 s->sys_func == sys_newfstatat ||
209 s->sys_func == sys_mknodat ||
210 s->sys_func == sys_openat ||
211 s->sys_func == sys_readlinkat ||
212 s->sys_func == sys_utimensat ||
213 s->sys_func == sys_fchownat ||
214 s->sys_func == sys_pipe2)
217 return fdmatch(tcp, tcp->u_arg[0]) ||
218 upathmatch(tcp, tcp->u_arg[1]);
221 if (s->sys_func == sys_link ||
222 s->sys_func == sys_mount)
225 return upathmatch(tcp, tcp->u_arg[0]) ||
226 upathmatch(tcp, tcp->u_arg[1]);
229 if (s->sys_func == sys_renameat ||
230 s->sys_func == sys_linkat)
232 /* fd, path, fd, path */
233 return fdmatch(tcp, tcp->u_arg[0]) ||
234 fdmatch(tcp, tcp->u_arg[2]) ||
235 upathmatch(tcp, tcp->u_arg[1]) ||
236 upathmatch(tcp, tcp->u_arg[3]);
239 if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap) {
241 return fdmatch(tcp, tcp->u_arg[4]);
244 if (s->sys_func == sys_symlinkat) {
246 return fdmatch(tcp, tcp->u_arg[1]) ||
247 upathmatch(tcp, tcp->u_arg[0]) ||
248 upathmatch(tcp, tcp->u_arg[2]);
251 if (s->sys_func == sys_splice) {
252 /* fd, x, fd, x, x */
253 return fdmatch(tcp, tcp->u_arg[0]) ||
254 fdmatch(tcp, tcp->u_arg[2]);
257 if (s->sys_func == sys_epoll_ctl) {
259 return fdmatch(tcp, tcp->u_arg[2]);
262 if (s->sys_func == sys_select ||
263 s->sys_func == sys_oldselect ||
264 s->sys_func == sys_pselect6)
268 long *args, oldargs[5];
272 if (s->sys_func == sys_oldselect) {
273 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
274 (char*) oldargs) < 0)
276 fprintf(stderr, "umoven() failed\n");
284 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
285 if (args[0] > 1024*1024)
289 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
291 fds = malloc(fdsize);
295 for (i = 1; i <= 3; ++i) {
299 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
300 fprintf(stderr, "umoven() failed\n");
304 for (j = 0; j < nfds; ++j)
305 if (FD_ISSET(j, fds) && fdmatch(tcp, j)) {
314 if (s->sys_func == sys_poll ||
315 s->sys_func == sys_ppoll)
319 unsigned long start, cur, end;
321 start = tcp->u_arg[0];
322 nfds = tcp->u_arg[1];
324 end = start + sizeof(fds) * nfds;
326 if (nfds == 0 || end < start)
329 for (cur = start; cur < end; cur += sizeof(fds))
330 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
331 && fdmatch(tcp, fds.fd))
337 if (s->sys_func == printargs ||
338 s->sys_func == sys_pipe ||
339 s->sys_func == sys_pipe2 ||
340 s->sys_func == sys_eventfd2 ||
341 s->sys_func == sys_eventfd ||
342 s->sys_func == sys_inotify_init1 ||
343 s->sys_func == sys_timerfd_create ||
344 s->sys_func == sys_timerfd_settime ||
345 s->sys_func == sys_timerfd_gettime ||
346 s->sys_func == sys_epoll_create ||
347 !strcmp(s->sys_name, "fanotify_init"))
350 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
351 * don't have any file descriptor or path args to test.
357 * Our fallback position for calls that haven't already
358 * been handled is to just check arg[0].
361 if (s->sys_flags & TRACE_FILE)
362 return upathmatch(tcp, tcp->u_arg[0]);
364 if (s->sys_flags & TRACE_DESC)
365 return fdmatch(tcp, tcp->u_arg[0]);