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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25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 #ifdef HAVE_SYS_POLL_H
43 #define MAXSELECTED 256 /* max number of "selected" paths */
44 static const char *selected[MAXSELECTED]; /* paths selected for tracing */
47 * Return true if specified path matches one that we're tracing.
50 pathmatch(const char *path)
54 for (i = 0; i < ARRAY_SIZE(selected); ++i)
56 if (selected[i] == NULL)
58 if (!strcmp(path, selected[i]))
65 * Return true if specified path (in user-space) matches.
68 upathmatch(struct tcb *tcp, unsigned long upath)
70 char path[PATH_MAX + 1];
72 return umovestr(tcp, upath, sizeof path, path) == 0 &&
77 * Return true if specified fd maps to a path we're tracing.
80 fdmatch(struct tcb *tcp, int fd)
82 const char *path = getfdpath(tcp, fd);
84 return path && pathmatch(path);
88 * Add a path to the set we're tracing.
89 * Secifying NULL will delete all paths.
92 storepath(const char *path)
98 for (i = 0; i < ARRAY_SIZE(selected); ++i)
101 free((char *) selected[i]);
107 for (i = 0; i < ARRAY_SIZE(selected); ++i)
114 fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
115 (unsigned int) ARRAY_SIZE(selected));
120 * Get path associated with fd.
122 const char *getfdpath(struct tcb *tcp, int fd)
125 static char path[PATH_MAX+1];
132 snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
133 n = readlink(linkpath, path, (sizeof path) - 1);
144 * Add a path to the set we're tracing. Also add the canonicalized
145 * version of the path. Secifying NULL will delete all paths.
148 pathtrace_select(const char *path)
153 return storepath(path);
158 rpath = realpath(path, NULL);
163 /* if realpath and specified path are same, we're done */
164 if (!strcmp(path, rpath))
170 fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
172 return storepath(rpath);
176 * Return true if syscall accesses a selected path
177 * (or if no paths have been specified for tracing).
180 pathtrace_match(struct tcb *tcp)
182 const struct sysent *s;
184 if (selected[0] == NULL)
187 s = &sysent[tcp->scno];
189 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
193 * Check for special cases where we need to do something
194 * other than test arg[0].
199 if (s->sys_func == sys_dup2 ||
200 s->sys_func == sys_dup3 ||
201 s->sys_func == sys_sendfile ||
202 s->sys_func == sys_sendfile64 ||
203 !strcmp(s->sys_name, "tee"))
206 return fdmatch(tcp, tcp->u_arg[0]) ||
207 fdmatch(tcp, tcp->u_arg[1]);
210 if (s->sys_func == sys_inotify_add_watch ||
211 s->sys_func == sys_faccessat ||
212 s->sys_func == sys_fchmodat ||
213 s->sys_func == sys_futimesat ||
214 s->sys_func == sys_mkdirat ||
215 s->sys_func == sys_unlinkat ||
216 s->sys_func == sys_newfstatat ||
217 s->sys_func == sys_mknodat ||
218 s->sys_func == sys_openat ||
219 s->sys_func == sys_readlinkat ||
220 s->sys_func == sys_utimensat ||
221 s->sys_func == sys_fchownat ||
222 s->sys_func == sys_pipe2)
225 return fdmatch(tcp, tcp->u_arg[0]) ||
226 upathmatch(tcp, tcp->u_arg[1]);
229 if (s->sys_func == sys_link ||
230 s->sys_func == sys_pivotroot ||
231 s->sys_func == sys_rename ||
232 s->sys_func == sys_symlink ||
233 s->sys_func == sys_mount)
236 return upathmatch(tcp, tcp->u_arg[0]) ||
237 upathmatch(tcp, tcp->u_arg[1]);
240 if (s->sys_func == sys_renameat ||
241 s->sys_func == sys_linkat)
243 /* fd, path, fd, path */
244 return fdmatch(tcp, tcp->u_arg[0]) ||
245 fdmatch(tcp, tcp->u_arg[2]) ||
246 upathmatch(tcp, tcp->u_arg[1]) ||
247 upathmatch(tcp, tcp->u_arg[3]);
250 if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap)
253 return fdmatch(tcp, tcp->u_arg[4]);
256 if (s->sys_func == sys_symlinkat)
259 return fdmatch(tcp, tcp->u_arg[1]) ||
260 upathmatch(tcp, tcp->u_arg[0]) ||
261 upathmatch(tcp, tcp->u_arg[2]);
264 if (!strcmp(s->sys_name, "splice"))
266 /* fd, x, fd, x, x */
267 return fdmatch(tcp, tcp->u_arg[0]) ||
268 fdmatch(tcp, tcp->u_arg[2]);
271 if (s->sys_func == sys_epoll_ctl)
274 return fdmatch(tcp, tcp->u_arg[2]);
277 if (s->sys_func == sys_select ||
278 s->sys_func == sys_oldselect ||
279 s->sys_func == sys_pselect6)
282 long *args, oldargs[5];
286 if (s->sys_func == sys_oldselect)
288 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
289 (char*) oldargs) < 0)
291 fprintf(stderr, "umoven() failed\n");
299 fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
301 fds = malloc(fdsize);
305 fprintf(stderr, "out of memory\n");
309 for (i = 1; i <= 3; ++i)
314 if (umoven(tcp, args[i], fdsize, (char *) fds) < 0)
316 fprintf(stderr, "umoven() failed\n");
320 for (j = 0; j < nfds; ++j)
321 if (FD_ISSET(j, fds) && fdmatch(tcp, j))
331 if (s->sys_func == sys_poll ||
332 s->sys_func == sys_ppoll)
336 unsigned long start, cur, end;
338 start = tcp->u_arg[0];
339 nfds = tcp->u_arg[1];
341 end = start + sizeof(fds) * nfds;
343 if (nfds == 0 || end < start)
346 for (cur = start; cur < end; cur += sizeof(fds))
347 if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
348 && fdmatch(tcp, fds.fd))
354 if (s->sys_func == printargs ||
355 s->sys_func == sys_pipe ||
356 s->sys_func == sys_pipe2 ||
357 s->sys_func == sys_eventfd2 ||
358 s->sys_func == sys_eventfd ||
359 s->sys_func == sys_inotify_init1 ||
360 s->sys_func == sys_timerfd_create ||
361 s->sys_func == sys_timerfd_settime ||
362 s->sys_func == sys_timerfd_gettime ||
363 s->sys_func == sys_epoll_create ||
364 !strcmp(s->sys_name, "fanotify_init"))
367 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
368 * don't have any file descriptor or path args to test.
373 #warning "path tracing only using arg[0]"
377 * Our fallback position for calls that haven't already
378 * been handled is to just check arg[0].
381 if (s->sys_flags & TRACE_FILE)
382 return upathmatch(tcp, tcp->u_arg[0]);
384 if (s->sys_flags & TRACE_DESC)
385 return fdmatch(tcp, tcp->u_arg[0]);