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>
31 #if defined HAVE_POLL_H
33 #elif defined HAVE_SYS_POLL_H
34 # include <sys/poll.h>
39 const char **paths_selected = NULL;
40 static unsigned num_selected = 0;
43 * Return true if specified path matches one that we're tracing.
46 pathmatch(const char *path)
50 for (i = 0; i < num_selected; ++i) {
51 if (strcmp(path, paths_selected[i]) == 0)
58 * Return true if specified path (in user-space) matches.
61 upathmatch(struct tcb *tcp, unsigned long upath)
63 char path[PATH_MAX + 1];
65 return umovestr(tcp, upath, sizeof path, path) > 0 &&
70 * Return true if specified fd maps to a path we're tracing.
73 fdmatch(struct tcb *tcp, int fd)
75 char path[PATH_MAX + 1];
76 int n = getfdpath(tcp, fd, path, sizeof(path));
78 return n >= 0 && pathmatch(path);
82 * Add a path to the set we're tracing.
83 * Specifying NULL will delete all paths.
86 storepath(const char *path)
91 return; /* already in table */
94 paths_selected = xreallocarray(paths_selected, num_selected,
95 sizeof(paths_selected[0]));
96 paths_selected[i] = path;
100 * Get path associated with fd.
103 getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize)
105 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3];
111 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
112 n = readlink(linkpath, buf, bufsize - 1);
114 * NB: if buf is too small, readlink doesn't fail,
115 * it returns truncated result (IOW: n == bufsize - 1).
123 * Add a path to the set we're tracing. Also add the canonicalized
124 * version of the path. Secifying NULL will delete all paths.
127 pathtrace_select(const char *path)
133 rpath = realpath(path, NULL);
138 /* if realpath and specified path are same, we're done */
139 if (strcmp(path, rpath) == 0) {
144 error_msg("Requested path '%s' resolved into '%s'", path, rpath);
149 * Return true if syscall accesses a selected path
150 * (or if no paths have been specified for tracing).
153 pathtrace_match(struct tcb *tcp)
155 const struct_sysent *s;
159 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
163 * Check for special cases where we need to do something
164 * other than test arg[0].
167 if (s->sys_func == sys_dup2 ||
168 s->sys_func == sys_dup3 ||
169 s->sys_func == sys_sendfile ||
170 s->sys_func == sys_sendfile64 ||
171 s->sys_func == sys_tee)
174 return fdmatch(tcp, tcp->u_arg[0]) ||
175 fdmatch(tcp, tcp->u_arg[1]);
178 if (s->sys_func == sys_inotify_add_watch ||
179 s->sys_func == sys_faccessat ||
180 s->sys_func == sys_fchmodat ||
181 s->sys_func == sys_futimesat ||
182 s->sys_func == sys_unlinkat ||
183 s->sys_func == sys_newfstatat ||
184 s->sys_func == sys_mknodat ||
185 s->sys_func == sys_openat ||
186 s->sys_func == sys_readlinkat ||
187 s->sys_func == sys_utimensat ||
188 s->sys_func == sys_fchownat ||
189 s->sys_func == sys_pipe2)
192 return fdmatch(tcp, tcp->u_arg[0]) ||
193 upathmatch(tcp, tcp->u_arg[1]);
196 if (s->sys_func == sys_link ||
197 s->sys_func == sys_mount)
200 return upathmatch(tcp, tcp->u_arg[0]) ||
201 upathmatch(tcp, tcp->u_arg[1]);
204 if (s->sys_func == sys_quotactl)
207 return upathmatch(tcp, tcp->u_arg[1]);
210 if (s->sys_func == sys_renameat ||
211 s->sys_func == sys_renameat2 ||
212 s->sys_func == sys_linkat)
214 /* fd, path, fd, path */
215 return fdmatch(tcp, tcp->u_arg[0]) ||
216 fdmatch(tcp, tcp->u_arg[2]) ||
217 upathmatch(tcp, tcp->u_arg[1]) ||
218 upathmatch(tcp, tcp->u_arg[3]);
222 s->sys_func == sys_old_mmap ||
224 s->sys_func == sys_old_mmap_pgoff ||
226 s->sys_func == sys_mmap ||
227 s->sys_func == sys_mmap_pgoff ||
228 s->sys_func == sys_mmap_4koff
231 return fdmatch(tcp, tcp->u_arg[4]);
234 if (s->sys_func == sys_symlinkat) {
236 return fdmatch(tcp, tcp->u_arg[1]) ||
237 upathmatch(tcp, tcp->u_arg[0]) ||
238 upathmatch(tcp, tcp->u_arg[2]);
241 if (s->sys_func == sys_splice) {
242 /* fd, x, fd, x, x */
243 return fdmatch(tcp, tcp->u_arg[0]) ||
244 fdmatch(tcp, tcp->u_arg[2]);
247 if (s->sys_func == sys_epoll_ctl) {
249 return fdmatch(tcp, tcp->u_arg[2]);
252 if (s->sys_func == sys_fanotify_mark) {
253 /* x, x, x, fd, path */
254 return fdmatch(tcp, tcp->u_arg[3]) ||
255 upathmatch(tcp, tcp->u_arg[4]);
258 if (s->sys_func == sys_select ||
259 s->sys_func == sys_oldselect ||
260 s->sys_func == sys_pselect6)
264 long *args, oldargs[5];
269 if (s->sys_func == sys_oldselect) {
270 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
273 error_msg("umoven() failed");
279 /* Kernel truncates arg[0] to int, we do the same. */
280 nfds = (int) args[0];
281 /* Kernel rejects negative nfds, so we don't parse it either. */
284 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
285 if (nfds > 1024*1024)
287 fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
288 fds = xmalloc(fdsize);
290 for (i = 1; i <= 3; ++i) {
293 if (umoven(tcp, args[i], fdsize, fds) < 0) {
294 error_msg("umoven() failed");
298 j = next_set_bit(fds, j, nfds);
301 if (fdmatch(tcp, j)) {
311 if (s->sys_func == sys_poll ||
312 s->sys_func == sys_ppoll)
316 unsigned long start, cur, end;
318 start = tcp->u_arg[0];
319 nfds = tcp->u_arg[1];
321 end = start + sizeof(fds) * nfds;
323 if (nfds == 0 || end < start)
326 for (cur = start; cur < end; cur += sizeof(fds))
327 if ((umoven(tcp, cur, sizeof fds, &fds) == 0)
328 && fdmatch(tcp, fds.fd))
334 if (s->sys_func == printargs ||
335 s->sys_func == sys_pipe ||
336 s->sys_func == sys_pipe2 ||
337 s->sys_func == sys_eventfd2 ||
338 s->sys_func == sys_eventfd ||
339 s->sys_func == sys_inotify_init1 ||
340 s->sys_func == sys_timerfd_create ||
341 s->sys_func == sys_timerfd_settime ||
342 s->sys_func == sys_timerfd_gettime ||
343 s->sys_func == sys_epoll_create ||
344 s->sys_func == sys_socket ||
345 s->sys_func == sys_socketpair ||
346 s->sys_func == sys_fanotify_init)
349 * These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set,
350 * but they 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 | TRACE_NETWORK))
364 return fdmatch(tcp, tcp->u_arg[0]);