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.
37 #ifdef HAVE_SYS_POLL_H
43 #define NumElem(a) (int)(sizeof(a) / sizeof((a)[0]))
45 #define MAXSELECTED 256 /* max number of "selected" paths */
46 static const char *selected[MAXSELECTED]; /* paths selected for tracing */
49 * Return true if specified path matches one that we're tracing.
52 pathmatch(const char *path)
56 for (i = 0; i < NumElem(selected); ++i)
58 if (selected[i] == NULL)
60 if (!strcmp(path, selected[i]))
67 * Return true if specified path (in user-space) matches.
70 upathmatch(struct tcb *tcp, unsigned long upath)
72 char path[PATH_MAX + 1];
74 return umovestr(tcp, upath, sizeof path, path) == 0 &&
79 * Return true if specified fd maps to a path we're tracing.
82 fdmatch(struct tcb *tcp, int fd)
84 const char *path = getfdpath(tcp, fd);
86 return path && pathmatch(path);
90 * Add a path to the set we're tracing.
91 * Secifying NULL will delete all paths.
94 storepath(const char *path)
100 for (i = 0; i < NumElem(selected); ++i)
103 free((char *) selected[i]);
109 for (i = 0; i < NumElem(selected); ++i)
116 fprintf(stderr, "Max trace paths exceeded, only using first %d\n",
122 * Get path associated with fd.
124 const char *getfdpath(struct tcb *tcp, int fd)
127 static char path[PATH_MAX+1];
134 snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
135 n = readlink(linkpath, path, (sizeof path) - 1);
146 * Add a path to the set we're tracing. Also add the canonicalized
147 * version of the path. Secifying NULL will delete all paths.
150 pathtrace_select(const char *path)
155 return storepath(path);
160 rpath = realpath(path, NULL);
165 /* if realpath and specified path are same, we're done */
166 if (!strcmp(path, rpath))
172 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
174 return storepath(rpath);
178 * Return true if syscall accesses a selected path
179 * (or if no paths have been specified for tracing).
182 pathtrace_match(struct tcb *tcp)
184 const struct sysent *s;
186 if (selected[0] == NULL)
189 s = &sysent[tcp->scno];
191 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
195 * Check for special cases where we need to do something
196 * other than test arg[0].
201 if (s->sys_func == sys_dup2 ||
202 s->sys_func == sys_dup3 ||
203 s->sys_func == sys_sendfile ||
204 s->sys_func == sys_sendfile64 ||
205 !strcmp(s->sys_name, "tee"))
208 return fdmatch(tcp, tcp->u_arg[0]) ||
209 fdmatch(tcp, tcp->u_arg[1]);
212 if (s->sys_func == sys_inotify_add_watch ||
213 s->sys_func == sys_faccessat ||
214 s->sys_func == sys_fchmodat ||
215 s->sys_func == sys_futimesat ||
216 s->sys_func == sys_mkdirat ||
217 s->sys_func == sys_unlinkat ||
218 s->sys_func == sys_newfstatat ||
219 s->sys_func == sys_mknodat ||
220 s->sys_func == sys_openat ||
221 s->sys_func == sys_readlinkat ||
222 s->sys_func == sys_utimensat ||
223 s->sys_func == sys_fchownat ||
224 s->sys_func == sys_pipe2)
227 return fdmatch(tcp, tcp->u_arg[0]) ||
228 upathmatch(tcp, tcp->u_arg[1]);
231 if (s->sys_func == sys_link ||
232 s->sys_func == sys_pivotroot ||
233 s->sys_func == sys_rename ||
234 s->sys_func == sys_symlink ||
235 s->sys_func == sys_mount)
238 return upathmatch(tcp, tcp->u_arg[0]) ||
239 upathmatch(tcp, tcp->u_arg[1]);
242 if (s->sys_func == sys_renameat ||
243 s->sys_func == sys_linkat)
245 /* fd, path, fd, path */
246 return fdmatch(tcp, tcp->u_arg[0]) ||
247 fdmatch(tcp, tcp->u_arg[2]) ||
248 upathmatch(tcp, tcp->u_arg[1]) ||
249 upathmatch(tcp, tcp->u_arg[3]);
252 if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap)
255 return fdmatch(tcp, tcp->u_arg[4]);
258 if (s->sys_func == sys_symlinkat)
261 return fdmatch(tcp, tcp->u_arg[1]) ||
262 upathmatch(tcp, tcp->u_arg[0]) ||
263 upathmatch(tcp, tcp->u_arg[2]);
266 if (!strcmp(s->sys_name, "splice"))
268 /* fd, x, fd, x, x */
269 return fdmatch(tcp, tcp->u_arg[0]) ||
270 fdmatch(tcp, tcp->u_arg[2]);
273 if (s->sys_func == sys_epoll_ctl)
276 return fdmatch(tcp, tcp->u_arg[2]);
279 if (s->sys_func == sys_select ||
280 s->sys_func == sys_oldselect ||
281 s->sys_func == sys_pselect6)
284 long *args, oldargs[5];
288 if (s->sys_func == sys_oldselect)
290 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
291 (char*) oldargs) < 0)
293 fprintf(stderr, "umoven() failed\n");
301 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
303 fds = malloc(fdsize);
307 fprintf(stderr, "out of memory\n");
311 for (i = 1; i <= 3; ++i)
316 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0)
318 fprintf(stderr, "umoven() failed\n");
322 for (j = 0; j < nfds; ++j)
323 if (FD_ISSET(j, fds) && fdmatch(tcp, j))
333 if (s->sys_func == sys_poll ||
334 s->sys_func == sys_ppoll)
338 unsigned long start, cur, end;
340 start = tcp->u_arg[0];
341 nfds = tcp->u_arg[1];
343 end = start + sizeof(fds) * nfds;
345 if (nfds == 0 || end < start)
348 for (cur = start; cur < end; cur += sizeof(fds))
349 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
350 && fdmatch(tcp, fds.fd))
356 if (s->sys_func == printargs ||
357 s->sys_func == sys_pipe ||
358 s->sys_func == sys_pipe2 ||
359 s->sys_func == sys_eventfd2 ||
360 s->sys_func == sys_eventfd ||
361 s->sys_func == sys_inotify_init1 ||
362 s->sys_func == sys_timerfd_create ||
363 s->sys_func == sys_timerfd_settime ||
364 s->sys_func == sys_timerfd_gettime ||
365 s->sys_func == sys_epoll_create ||
366 !strcmp(s->sys_name, "fanotify_init"))
369 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
370 * don't have any file descriptor or path args to test.
375 #warning "path tracing only using arg[0]"
379 * Our fallback position for calls that haven't already
380 * been handled is to just check arg[0].
383 if (s->sys_flags & TRACE_FILE)
384 return upathmatch(tcp, tcp->u_arg[0]);
386 if (s->sys_flags & TRACE_DESC)
387 return fdmatch(tcp, tcp->u_arg[0]);