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.
31 #include <sys/param.h>
36 #ifdef HAVE_SYS_POLL_H
42 #define MAXSELECTED 256 /* max number of "selected" paths */
43 static const char *selected[MAXSELECTED]; /* paths selected for tracing */
46 * Return true if specified path matches one that we're tracing.
49 pathmatch(const char *path)
53 for (i = 0; i < ARRAY_SIZE(selected); ++i) {
54 if (selected[i] == NULL)
56 if (!strcmp(path, selected[i]))
63 * Return true if specified path (in user-space) matches.
66 upathmatch(struct tcb *tcp, unsigned long upath)
68 char path[PATH_MAX + 1];
70 return umovestr(tcp, upath, sizeof path, path) >= 0 &&
75 * Return true if specified fd maps to a path we're tracing.
78 fdmatch(struct tcb *tcp, int fd)
80 const char *path = getfdpath(tcp, fd);
82 return path && pathmatch(path);
86 * Add a path to the set we're tracing.
87 * Secifying NULL will delete all paths.
90 storepath(const char *path)
95 for (i = 0; i < ARRAY_SIZE(selected); ++i)
97 free((char *) selected[i]);
103 for (i = 0; i < ARRAY_SIZE(selected); ++i)
109 fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
110 (unsigned int) ARRAY_SIZE(selected));
115 * Get path associated with fd.
117 const char *getfdpath(struct tcb *tcp, int fd)
119 static char path[PATH_MAX+1];
126 snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
127 n = readlink(linkpath, path, (sizeof path) - 1);
135 * Add a path to the set we're tracing. Also add the canonicalized
136 * version of the path. Secifying NULL will delete all paths.
139 pathtrace_select(const char *path)
144 return storepath(path);
149 rpath = realpath(path, NULL);
154 /* if realpath and specified path are same, we're done */
155 if (!strcmp(path, rpath)) {
160 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
162 return storepath(rpath);
166 * Return true if syscall accesses a selected path
167 * (or if no paths have been specified for tracing).
170 pathtrace_match(struct tcb *tcp)
172 const struct sysent *s;
174 if (selected[0] == NULL)
177 if (!SCNO_IN_RANGE(tcp->scno))
180 s = &sysent[tcp->scno];
182 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
186 * Check for special cases where we need to do something
187 * other than test arg[0].
190 if (s->sys_func == sys_dup2 ||
191 s->sys_func == sys_dup3 ||
192 s->sys_func == sys_sendfile ||
193 s->sys_func == sys_sendfile64 ||
194 s->sys_func == sys_tee)
197 return fdmatch(tcp, tcp->u_arg[0]) ||
198 fdmatch(tcp, tcp->u_arg[1]);
201 if (s->sys_func == sys_inotify_add_watch ||
202 s->sys_func == sys_faccessat ||
203 s->sys_func == sys_fchmodat ||
204 s->sys_func == sys_futimesat ||
205 s->sys_func == sys_mkdirat ||
206 s->sys_func == sys_unlinkat ||
207 s->sys_func == sys_newfstatat ||
208 s->sys_func == sys_mknodat ||
209 s->sys_func == sys_openat ||
210 s->sys_func == sys_readlinkat ||
211 s->sys_func == sys_utimensat ||
212 s->sys_func == sys_fchownat ||
213 s->sys_func == sys_pipe2)
216 return fdmatch(tcp, tcp->u_arg[0]) ||
217 upathmatch(tcp, tcp->u_arg[1]);
220 if (s->sys_func == sys_link ||
221 s->sys_func == sys_mount)
224 return upathmatch(tcp, tcp->u_arg[0]) ||
225 upathmatch(tcp, tcp->u_arg[1]);
228 if (s->sys_func == sys_renameat ||
229 s->sys_func == sys_linkat)
231 /* fd, path, fd, path */
232 return fdmatch(tcp, tcp->u_arg[0]) ||
233 fdmatch(tcp, tcp->u_arg[2]) ||
234 upathmatch(tcp, tcp->u_arg[1]) ||
235 upathmatch(tcp, tcp->u_arg[3]);
238 if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap) {
240 return fdmatch(tcp, tcp->u_arg[4]);
243 if (s->sys_func == sys_symlinkat) {
245 return fdmatch(tcp, tcp->u_arg[1]) ||
246 upathmatch(tcp, tcp->u_arg[0]) ||
247 upathmatch(tcp, tcp->u_arg[2]);
250 if (s->sys_func == sys_splice) {
251 /* fd, x, fd, x, x */
252 return fdmatch(tcp, tcp->u_arg[0]) ||
253 fdmatch(tcp, tcp->u_arg[2]);
256 if (s->sys_func == sys_epoll_ctl) {
258 return fdmatch(tcp, tcp->u_arg[2]);
261 if (s->sys_func == sys_select ||
262 s->sys_func == sys_oldselect ||
263 s->sys_func == sys_pselect6)
267 long *args, oldargs[5];
271 if (s->sys_func == sys_oldselect) {
272 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
273 (char*) oldargs) < 0)
275 fprintf(stderr, "umoven() failed\n");
283 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
284 if (args[0] > 1024*1024)
288 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
290 fds = malloc(fdsize);
294 for (i = 1; i <= 3; ++i) {
298 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
299 fprintf(stderr, "umoven() failed\n");
303 for (j = 0; j < nfds; ++j)
304 if (FD_ISSET(j, fds) && fdmatch(tcp, j)) {
313 if (s->sys_func == sys_poll ||
314 s->sys_func == sys_ppoll)
318 unsigned long start, cur, end;
320 start = tcp->u_arg[0];
321 nfds = tcp->u_arg[1];
323 end = start + sizeof(fds) * nfds;
325 if (nfds == 0 || end < start)
328 for (cur = start; cur < end; cur += sizeof(fds))
329 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
330 && fdmatch(tcp, fds.fd))
336 if (s->sys_func == printargs ||
337 s->sys_func == sys_pipe ||
338 s->sys_func == sys_pipe2 ||
339 s->sys_func == sys_eventfd2 ||
340 s->sys_func == sys_eventfd ||
341 s->sys_func == sys_inotify_init1 ||
342 s->sys_func == sys_timerfd_create ||
343 s->sys_func == sys_timerfd_settime ||
344 s->sys_func == sys_timerfd_gettime ||
345 s->sys_func == sys_epoll_create ||
346 !strcmp(s->sys_name, "fanotify_init"))
349 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
350 * don't have any file descriptor or path args to test.
356 * Our fallback position for calls that haven't already
357 * been handled is to just check arg[0].
360 if (s->sys_flags & TRACE_FILE)
361 return upathmatch(tcp, tcp->u_arg[0]);
363 if (s->sys_flags & TRACE_DESC)
364 return fdmatch(tcp, tcp->u_arg[0]);