2 * Copyright (c) 2011 Comtrol Corp.
3 * Copyright (c) 2011-2017 The strace developers.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 #include <sys/param.h>
36 const char **paths_selected;
37 static unsigned int num_selected;
40 * Return true if specified path matches one that we're tracing.
43 pathmatch(const char *path)
47 for (i = 0; i < num_selected; ++i) {
48 if (strcmp(path, paths_selected[i]) == 0)
55 * Return true if specified path (in user-space) matches.
58 upathmatch(struct tcb *const tcp, const kernel_ulong_t upath)
60 char path[PATH_MAX + 1];
62 return umovestr(tcp, upath, sizeof(path), path) > 0 &&
67 * Return true if specified fd maps to a path we're tracing.
70 fdmatch(struct tcb *tcp, int fd)
72 char path[PATH_MAX + 1];
73 int n = getfdpath(tcp, fd, path, sizeof(path));
75 return n >= 0 && pathmatch(path);
79 * Add a path to the set we're tracing.
80 * Specifying NULL will delete all paths.
83 storepath(const char *path)
88 return; /* already in table */
91 paths_selected = xreallocarray(paths_selected, num_selected,
92 sizeof(paths_selected[0]));
93 paths_selected[i] = path;
97 * Get path associated with fd.
100 getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize)
102 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3];
108 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
109 n = readlink(linkpath, buf, bufsize - 1);
111 * NB: if buf is too small, readlink doesn't fail,
112 * it returns truncated result (IOW: n == bufsize - 1).
120 * Add a path to the set we're tracing. Also add the canonicalized
121 * version of the path. Secifying NULL will delete all paths.
124 pathtrace_select(const char *path)
130 rpath = realpath(path, NULL);
135 /* if realpath and specified path are same, we're done */
136 if (strcmp(path, rpath) == 0) {
141 error_msg("Requested path '%s' resolved into '%s'", path, rpath);
146 * Return true if syscall accesses a selected path
147 * (or if no paths have been specified for tracing).
150 pathtrace_match(struct tcb *tcp)
152 const struct_sysent *s;
156 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
160 * Check for special cases where we need to do something
161 * other than test arg[0].
167 case SEN_kexec_file_load:
172 return fdmatch(tcp, tcp->u_arg[0]) ||
173 fdmatch(tcp, tcp->u_arg[1]);
180 case SEN_inotify_add_watch:
183 case SEN_name_to_handle_at:
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:
223 return fdmatch(tcp, tcp->u_arg[4]);
227 return fdmatch(tcp, tcp->u_arg[1]) ||
228 upathmatch(tcp, tcp->u_arg[0]) ||
229 upathmatch(tcp, tcp->u_arg[2]);
231 case SEN_copy_file_range:
233 /* fd, x, fd, x, x, x */
234 return fdmatch(tcp, tcp->u_arg[0]) ||
235 fdmatch(tcp, tcp->u_arg[2]);
239 return fdmatch(tcp, tcp->u_arg[2]);
242 case SEN_fanotify_mark:
243 /* x, x, x, fd, path */
244 return fdmatch(tcp, tcp->u_arg[3]) ||
245 upathmatch(tcp, tcp->u_arg[4]);
253 kernel_ulong_t *args;
254 kernel_ulong_t select_args[5];
255 unsigned int oldselect_args[5];
259 if (SEN_oldselect == s->sen) {
260 if (sizeof(*select_args) == sizeof(*oldselect_args)) {
261 if (umove(tcp, tcp->u_arg[0], &select_args)) {
267 if (umove(tcp, tcp->u_arg[0], &oldselect_args)) {
271 for (n = 0; n < 5; ++n) {
272 select_args[n] = oldselect_args[n];
280 /* Kernel truncates arg[0] to int, we do the same. */
281 nfds = (int) args[0];
282 /* Kernel rejects negative nfds, so we don't parse it either. */
285 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
286 if (nfds > 1024*1024)
288 fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
289 fds = xmalloc(fdsize);
291 for (i = 1; i <= 3; ++i) {
294 if (umoven(tcp, args[i], fdsize, fds) < 0) {
298 j = next_set_bit(fds, j, nfds);
301 if (fdmatch(tcp, j)) {
316 kernel_ulong_t 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 ((umove(tcp, cur, &fds) == 0)
328 && fdmatch(tcp, fds.fd))
335 case SEN_epoll_create:
336 case SEN_epoll_create1:
339 case SEN_fanotify_init:
340 case SEN_inotify_init1:
341 case SEN_memfd_create:
342 case SEN_perf_event_open:
348 case SEN_timerfd_create:
349 case SEN_timerfd_gettime:
350 case SEN_timerfd_settime:
351 case SEN_userfaultfd:
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]);