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].
174 return fdmatch(tcp, tcp->u_arg[0]) ||
175 fdmatch(tcp, tcp->u_arg[1]);
181 case SEN_inotify_add_watch:
191 return fdmatch(tcp, tcp->u_arg[0]) ||
192 upathmatch(tcp, tcp->u_arg[1]);
198 return upathmatch(tcp, tcp->u_arg[0]) ||
199 upathmatch(tcp, tcp->u_arg[1]);
203 return upathmatch(tcp, tcp->u_arg[1]);
208 /* fd, path, fd, path */
209 return fdmatch(tcp, tcp->u_arg[0]) ||
210 fdmatch(tcp, tcp->u_arg[2]) ||
211 upathmatch(tcp, tcp->u_arg[1]) ||
212 upathmatch(tcp, tcp->u_arg[3]);
216 case SEN_old_mmap_pgoff:
222 return fdmatch(tcp, tcp->u_arg[4]);
226 return fdmatch(tcp, tcp->u_arg[1]) ||
227 upathmatch(tcp, tcp->u_arg[0]) ||
228 upathmatch(tcp, tcp->u_arg[2]);
231 /* fd, x, fd, x, x */
232 return fdmatch(tcp, tcp->u_arg[0]) ||
233 fdmatch(tcp, tcp->u_arg[2]);
237 return fdmatch(tcp, tcp->u_arg[2]);
240 case SEN_fanotify_mark:
241 /* x, x, x, fd, path */
242 return fdmatch(tcp, tcp->u_arg[3]) ||
243 upathmatch(tcp, tcp->u_arg[4]);
251 long *args, oldargs[5];
256 if (SEN_oldselect == s->sen) {
257 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
260 error_msg("umoven() failed");
266 /* Kernel truncates arg[0] to int, we do the same. */
267 nfds = (int) args[0];
268 /* Kernel rejects negative nfds, so we don't parse it either. */
271 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
272 if (nfds > 1024*1024)
274 fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
275 fds = xmalloc(fdsize);
277 for (i = 1; i <= 3; ++i) {
280 if (umoven(tcp, args[i], fdsize, fds) < 0) {
281 error_msg("umoven() failed");
285 j = next_set_bit(fds, j, nfds);
288 if (fdmatch(tcp, j)) {
303 unsigned long start, cur, end;
305 start = tcp->u_arg[0];
306 nfds = tcp->u_arg[1];
308 end = start + sizeof(fds) * nfds;
310 if (nfds == 0 || end < start)
313 for (cur = start; cur < end; cur += sizeof(fds))
314 if ((umoven(tcp, cur, sizeof fds, &fds) == 0)
315 && fdmatch(tcp, fds.fd))
321 case SEN_epoll_create:
324 case SEN_fanotify_init:
325 case SEN_inotify_init1:
326 case SEN_perf_event_open:
331 case SEN_timerfd_create:
332 case SEN_timerfd_gettime:
333 case SEN_timerfd_settime:
335 * These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set,
336 * but they don't have any file descriptor or path args to test.
342 * Our fallback position for calls that haven't already
343 * been handled is to just check arg[0].
346 if (s->sys_flags & TRACE_FILE)
347 return upathmatch(tcp, tcp->u_arg[0]);
349 if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK))
350 return fdmatch(tcp, tcp->u_arg[0]);