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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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]) == 0)
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)
94 for (i = 0; i < ARRAY_SIZE(selected); ++i) {
101 fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
102 (unsigned int) ARRAY_SIZE(selected));
107 * Get path associated with fd.
110 getfdpath(struct tcb *tcp, int fd)
112 static char path[PATH_MAX+1];
113 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)];
119 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
120 n = readlink(linkpath, path, (sizeof path) - 1);
128 * Add a path to the set we're tracing. Also add the canonicalized
129 * version of the path. Secifying NULL will delete all paths.
132 pathtrace_select(const char *path)
139 rpath = realpath(path, NULL);
144 /* if realpath and specified path are same, we're done */
145 if (strcmp(path, rpath) == 0) {
150 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
152 return storepath(rpath);
156 * Return true if syscall accesses a selected path
157 * (or if no paths have been specified for tracing).
160 pathtrace_match(struct tcb *tcp)
162 const struct sysent *s;
164 if (selected[0] == NULL)
167 if (!SCNO_IN_RANGE(tcp->scno))
170 s = &sysent[tcp->scno];
172 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
176 * Check for special cases where we need to do something
177 * other than test arg[0].
180 if (s->sys_func == sys_dup2 ||
181 s->sys_func == sys_dup3 ||
182 s->sys_func == sys_sendfile ||
183 s->sys_func == sys_sendfile64 ||
184 s->sys_func == sys_tee)
187 return fdmatch(tcp, tcp->u_arg[0]) ||
188 fdmatch(tcp, tcp->u_arg[1]);
191 if (s->sys_func == sys_inotify_add_watch ||
192 s->sys_func == sys_faccessat ||
193 s->sys_func == sys_fchmodat ||
194 s->sys_func == sys_futimesat ||
195 s->sys_func == sys_mkdirat ||
196 s->sys_func == sys_unlinkat ||
197 s->sys_func == sys_newfstatat ||
198 s->sys_func == sys_mknodat ||
199 s->sys_func == sys_openat ||
200 s->sys_func == sys_readlinkat ||
201 s->sys_func == sys_utimensat ||
202 s->sys_func == sys_fchownat ||
203 s->sys_func == sys_pipe2)
206 return fdmatch(tcp, tcp->u_arg[0]) ||
207 upathmatch(tcp, tcp->u_arg[1]);
210 if (s->sys_func == sys_link ||
211 s->sys_func == sys_mount)
214 return upathmatch(tcp, tcp->u_arg[0]) ||
215 upathmatch(tcp, tcp->u_arg[1]);
218 if (s->sys_func == sys_renameat ||
219 s->sys_func == sys_linkat)
221 /* fd, path, fd, path */
222 return fdmatch(tcp, tcp->u_arg[0]) ||
223 fdmatch(tcp, tcp->u_arg[2]) ||
224 upathmatch(tcp, tcp->u_arg[1]) ||
225 upathmatch(tcp, tcp->u_arg[3]);
228 if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap) {
230 return fdmatch(tcp, tcp->u_arg[4]);
233 if (s->sys_func == sys_symlinkat) {
235 return fdmatch(tcp, tcp->u_arg[1]) ||
236 upathmatch(tcp, tcp->u_arg[0]) ||
237 upathmatch(tcp, tcp->u_arg[2]);
240 if (s->sys_func == sys_splice) {
241 /* fd, x, fd, x, x */
242 return fdmatch(tcp, tcp->u_arg[0]) ||
243 fdmatch(tcp, tcp->u_arg[2]);
246 if (s->sys_func == sys_epoll_ctl) {
248 return fdmatch(tcp, tcp->u_arg[2]);
251 if (s->sys_func == sys_select ||
252 s->sys_func == sys_oldselect ||
253 s->sys_func == sys_pselect6)
257 long *args, oldargs[5];
261 if (s->sys_func == sys_oldselect) {
262 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
263 (char*) oldargs) < 0)
265 fprintf(stderr, "umoven() failed\n");
273 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
274 if (args[0] > 1024*1024)
278 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
280 fds = malloc(fdsize);
284 for (i = 1; i <= 3; ++i) {
288 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0) {
289 fprintf(stderr, "umoven() failed\n");
293 for (j = 0; j < nfds; ++j)
294 if (FD_ISSET(j, fds) && fdmatch(tcp, j)) {
303 if (s->sys_func == sys_poll ||
304 s->sys_func == sys_ppoll)
308 unsigned long start, cur, end;
310 start = tcp->u_arg[0];
311 nfds = tcp->u_arg[1];
313 end = start + sizeof(fds) * nfds;
315 if (nfds == 0 || end < start)
318 for (cur = start; cur < end; cur += sizeof(fds))
319 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
320 && fdmatch(tcp, fds.fd))
326 if (s->sys_func == printargs ||
327 s->sys_func == sys_pipe ||
328 s->sys_func == sys_pipe2 ||
329 s->sys_func == sys_eventfd2 ||
330 s->sys_func == sys_eventfd ||
331 s->sys_func == sys_inotify_init1 ||
332 s->sys_func == sys_timerfd_create ||
333 s->sys_func == sys_timerfd_settime ||
334 s->sys_func == sys_timerfd_gettime ||
335 s->sys_func == sys_epoll_create ||
336 strcmp(s->sys_name, "fanotify_init") == 0)
339 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
340 * don't have any file descriptor or path args to test.
346 * Our fallback position for calls that haven't already
347 * been handled is to just check arg[0].
350 if (s->sys_flags & TRACE_FILE)
351 return upathmatch(tcp, tcp->u_arg[0]);
353 if (s->sys_flags & TRACE_DESC)
354 return fdmatch(tcp, tcp->u_arg[0]);