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 = realloc(paths_selected, num_selected * sizeof(paths_selected[0]));
97 paths_selected[i] = path;
101 * Get path associated with fd.
104 getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize)
106 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3];
112 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
113 n = readlink(linkpath, buf, bufsize - 1);
115 * NB: if buf is too small, readlink doesn't fail,
116 * it returns truncated result (IOW: n == bufsize - 1).
124 * Add a path to the set we're tracing. Also add the canonicalized
125 * version of the path. Secifying NULL will delete all paths.
128 pathtrace_select(const char *path)
134 rpath = realpath(path, NULL);
139 /* if realpath and specified path are same, we're done */
140 if (strcmp(path, rpath) == 0) {
145 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
151 * Return true if syscall accesses a selected path
152 * (or if no paths have been specified for tracing).
155 pathtrace_match(struct tcb *tcp)
157 const struct_sysent *s;
161 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
165 * Check for special cases where we need to do something
166 * other than test arg[0].
169 if (s->sys_func == sys_dup2 ||
170 s->sys_func == sys_dup3 ||
171 s->sys_func == sys_sendfile ||
172 s->sys_func == sys_sendfile64 ||
173 s->sys_func == sys_tee)
176 return fdmatch(tcp, tcp->u_arg[0]) ||
177 fdmatch(tcp, tcp->u_arg[1]);
180 if (s->sys_func == sys_inotify_add_watch ||
181 s->sys_func == sys_faccessat ||
182 s->sys_func == sys_fchmodat ||
183 s->sys_func == sys_futimesat ||
184 s->sys_func == sys_mkdirat ||
185 s->sys_func == sys_unlinkat ||
186 s->sys_func == sys_newfstatat ||
187 s->sys_func == sys_mknodat ||
188 s->sys_func == sys_openat ||
189 s->sys_func == sys_readlinkat ||
190 s->sys_func == sys_utimensat ||
191 s->sys_func == sys_fchownat ||
192 s->sys_func == sys_pipe2)
195 return fdmatch(tcp, tcp->u_arg[0]) ||
196 upathmatch(tcp, tcp->u_arg[1]);
199 if (s->sys_func == sys_link ||
200 s->sys_func == sys_mount)
203 return upathmatch(tcp, tcp->u_arg[0]) ||
204 upathmatch(tcp, tcp->u_arg[1]);
207 if (s->sys_func == sys_quotactl)
210 return upathmatch(tcp, tcp->u_arg[1]);
213 if (s->sys_func == sys_renameat ||
214 s->sys_func == sys_linkat)
216 /* fd, path, fd, path */
217 return fdmatch(tcp, tcp->u_arg[0]) ||
218 fdmatch(tcp, tcp->u_arg[2]) ||
219 upathmatch(tcp, tcp->u_arg[1]) ||
220 upathmatch(tcp, tcp->u_arg[3]);
224 s->sys_func == sys_old_mmap ||
226 s->sys_func == sys_old_mmap_pgoff ||
228 s->sys_func == sys_mmap ||
229 s->sys_func == sys_mmap_pgoff ||
230 s->sys_func == sys_mmap_4koff
233 return fdmatch(tcp, tcp->u_arg[4]);
236 if (s->sys_func == sys_symlinkat) {
238 return fdmatch(tcp, tcp->u_arg[1]) ||
239 upathmatch(tcp, tcp->u_arg[0]) ||
240 upathmatch(tcp, tcp->u_arg[2]);
243 if (s->sys_func == sys_splice) {
244 /* fd, x, fd, x, x */
245 return fdmatch(tcp, tcp->u_arg[0]) ||
246 fdmatch(tcp, tcp->u_arg[2]);
249 if (s->sys_func == sys_epoll_ctl) {
251 return fdmatch(tcp, tcp->u_arg[2]);
254 if (s->sys_func == sys_fanotify_mark) {
255 /* x, x, x, fd, path */
256 return fdmatch(tcp, tcp->u_arg[3]) ||
257 upathmatch(tcp, tcp->u_arg[4]);
260 if (s->sys_func == sys_select ||
261 s->sys_func == sys_oldselect ||
262 s->sys_func == sys_pselect6)
266 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");
281 /* Kernel truncates arg[0] to int, we do the same. */
282 nfds = (int) args[0];
283 /* Kernel rejects negative nfds, so we don't parse it either. */
286 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
287 if (nfds > 1024*1024)
289 fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
290 fds = malloc(fdsize);
294 for (i = 1; i <= 3; ++i) {
297 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
298 fprintf(stderr, "umoven() failed\n");
302 j = next_set_bit(fds, j, nfds);
305 if (fdmatch(tcp, j)) {
315 if (s->sys_func == sys_poll ||
316 s->sys_func == sys_ppoll)
320 unsigned long start, cur, end;
322 start = tcp->u_arg[0];
323 nfds = tcp->u_arg[1];
325 end = start + sizeof(fds) * nfds;
327 if (nfds == 0 || end < start)
330 for (cur = start; cur < end; cur += sizeof(fds))
331 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
332 && fdmatch(tcp, fds.fd))
338 if (s->sys_func == printargs ||
339 s->sys_func == sys_pipe ||
340 s->sys_func == sys_pipe2 ||
341 s->sys_func == sys_eventfd2 ||
342 s->sys_func == sys_eventfd ||
343 s->sys_func == sys_inotify_init1 ||
344 s->sys_func == sys_timerfd_create ||
345 s->sys_func == sys_timerfd_settime ||
346 s->sys_func == sys_timerfd_gettime ||
347 s->sys_func == sys_epoll_create ||
348 s->sys_func == sys_socket ||
349 s->sys_func == sys_socketpair ||
350 s->sys_func == sys_fanotify_init)
353 * These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set,
354 * but they don't have any file descriptor or path args to test.
360 * Our fallback position for calls that haven't already
361 * been handled is to just check arg[0].
364 if (s->sys_flags & TRACE_FILE)
365 return upathmatch(tcp, tcp->u_arg[0]);
367 if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK))
368 return fdmatch(tcp, tcp->u_arg[0]);