pathtrace.c - platform/external/strace - Gitiles

 /*
  * Copyright (c) 2011, Comtrol Corp.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */

 #include "defs.h"

 #include <ctype.h>
 #include <limits.h>

 #ifdef HAVE_POLL_H
 #include <poll.h>
 #endif
 #ifdef HAVE_SYS_POLL_H
 #include <sys/poll.h>
 #endif

 #include "syscall.h"

 #define NumElem(a)  (int)(sizeof(a) / sizeof((a)[0]))

 #define MAXSELECTED  256	/* max number of "selected" paths */
 static const char *selected[MAXSELECTED];	/* paths selected for tracing */

 /*
  * Return true if specified path matches one that we're tracing.
  */
 static int
 pathmatch(const char *path)
 {
 	int     i;

 	for (i = 0; i < NumElem(selected); ++i)
 	{
 		if (selected[i] == NULL)
 			return 0;
 		if (!strcmp(path, selected[i]))
 			return 1;
 	}
 	return 0;
 }

 /*
  * Return true if specified path (in user-space) matches.
  */
 static int
 upathmatch(struct tcb *tcp, unsigned long upath)
 {
 	char    path[PATH_MAX + 1];

 	return umovestr(tcp, upath, sizeof path, path) == 0 &&
 		pathmatch(path);
 }

 /*
  * Return true if specified fd maps to a path we're tracing.
  */
 static int
 fdmatch(struct tcb *tcp, int fd)
 {
 	const char *path = getfdpath(tcp, fd);

 	return path && pathmatch(path);
 }

 /*
  * Add a path to the set we're tracing.
  * Secifying NULL will delete all paths.
  */
 static int
 storepath(const char *path)
 {
 	int     i;

 	if (path == NULL)
 	{
 		for (i = 0; i < NumElem(selected); ++i)
 			if (selected[i])
 			{
 				free((char *) selected[i]);
 				selected[i] = NULL;
 			}
 		return 0;
 	}

 	for (i = 0; i < NumElem(selected); ++i)
 		if (!selected[i])
 		{
 			selected[i] = path;
 			return 0;
 		}

 	fprintf(stderr, "Max trace paths exceeded, only using first %d\n",
 		NumElem(selected));
 	return -1;
 }

 /*
  * Get path associated with fd.
  */
 const char *getfdpath(struct tcb *tcp, int fd)
 {
 #ifdef LINUX
 	static char path[PATH_MAX+1];
 	char linkpath[64];
 	ssize_t n;

 	if (fd < 0)
 		return NULL;

 	snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
 	n = readlink(linkpath, path, (sizeof path) - 1);
 	if (n <= 0)
 		return NULL;
 	path[n] = '\0';
 	return path;
 #else
 	return NULL;
 #endif
 }

 /*
  * Add a path to the set we're tracing.  Also add the canonicalized
  * version of the path.  Secifying NULL will delete all paths.
  */
 int
 pathtrace_select(const char *path)
 {
 	char   *rpath;

 	if (path == NULL)
 		return storepath(path);

 	if (storepath(path))
 		return -1;

 	rpath = realpath(path, NULL);

 	if (rpath == NULL)
 		return 0;

 	/* if realpath and specified path are same, we're done */
 	if (!strcmp(path, rpath))
 	{
 		free(rpath);
 		return 0;
 	}

 	fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
 		path, rpath);
 	return storepath(rpath);
 }

 /*
  * Return true if syscall accesses a selected path
  * (or if no paths have been specified for tracing).
  */
 int
 pathtrace_match(struct tcb *tcp)
 {
 	const struct sysent *s;

 	if (selected[0] == NULL)
 		return 1;

 	s = &sysent[tcp->scno];

 	if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC)))
 		return 0;

 	/*
 	 * Check for special cases where we need to do something
 	 * other than test arg[0].
 	 */

 #ifdef LINUX

 	if (s->sys_func == sys_dup2 ||
 	    s->sys_func == sys_dup3 ||
 	    s->sys_func == sys_sendfile ||
 	    s->sys_func == sys_sendfile64 ||
 	    !strcmp(s->sys_name, "tee"))
 	{
 		/* fd, fd */
 		return fdmatch(tcp, tcp->u_arg[0]) ||
 			fdmatch(tcp, tcp->u_arg[1]);
 	}

 	if (s->sys_func == sys_inotify_add_watch ||
 	    s->sys_func == sys_faccessat ||
 	    s->sys_func == sys_fchmodat ||
 	    s->sys_func == sys_futimesat ||
 	    s->sys_func == sys_mkdirat ||
 	    s->sys_func == sys_unlinkat ||
 	    s->sys_func == sys_newfstatat ||
 	    s->sys_func == sys_mknodat ||
 	    s->sys_func == sys_openat ||
 	    s->sys_func == sys_readlinkat ||
 	    s->sys_func == sys_utimensat ||
 	    s->sys_func == sys_fchownat ||
 	    s->sys_func == sys_pipe2)
 	{
 		/* fd, path */
 		return fdmatch(tcp, tcp->u_arg[0]) ||
 			upathmatch(tcp, tcp->u_arg[1]);
 	}

 	if (s->sys_func == sys_link ||
 	    s->sys_func == sys_pivotroot ||
 	    s->sys_func == sys_rename ||
 	    s->sys_func == sys_symlink ||
 	    s->sys_func == sys_mount)
 	{
 		/* path, path */
 		return upathmatch(tcp, tcp->u_arg[0]) ||
 			upathmatch(tcp, tcp->u_arg[1]);
 	}

 	if (s->sys_func == sys_renameat ||
 	    s->sys_func == sys_linkat)
 	{
 		/* fd, path, fd, path */
 		return fdmatch(tcp, tcp->u_arg[0]) ||
 			fdmatch(tcp, tcp->u_arg[2]) ||
 			upathmatch(tcp, tcp->u_arg[1]) ||
 			upathmatch(tcp, tcp->u_arg[3]);
 	}

 	if (s->sys_func == sys_old_mmap || s->sys_func == sys_mmap)
 	{
 		/* x, x, x, x, fd */
 		return fdmatch(tcp, tcp->u_arg[4]);
 	}

 	if (s->sys_func == sys_symlinkat)
 	{
 		/* path, fd, path */
 		return fdmatch(tcp, tcp->u_arg[1]) ||
 			upathmatch(tcp, tcp->u_arg[0]) ||
 			upathmatch(tcp, tcp->u_arg[2]);
 	}

 	if (!strcmp(s->sys_name, "splice"))
 	{
 		/* fd, x, fd, x, x */
 		return fdmatch(tcp, tcp->u_arg[0]) ||
 			fdmatch(tcp, tcp->u_arg[2]);
 	}

 	if (s->sys_func == sys_epoll_ctl)
 	{
 		/* x, x, fd, x */
 		return fdmatch(tcp, tcp->u_arg[2]);
 	}

 	if (s->sys_func == sys_select ||
 	    s->sys_func == sys_oldselect ||
 	    s->sys_func == sys_pselect6)
 	{
 		int     i, j, nfds;
 		long   *args, oldargs[5];
 		unsigned fdsize;
 		fd_set *fds;

 		if (s->sys_func == sys_oldselect)
 		{
 			if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
 				   (char*) oldargs) < 0)
 			{
 				fprintf(stderr, "umoven() failed\n");
 				return 0;
 			}
 			args = oldargs;
 		} else
 			args = tcp->u_arg;

 		nfds = args[0];
 		fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
 			  & -sizeof(long));
 		fds = malloc(fdsize);

 		if (fds == NULL)
 		{
 			fprintf(stderr, "out of memory\n");
 			return 0;
 		}

 		for (i = 1; i <= 3; ++i)
 		{
 			if (args[i] == 0)
 				continue;

 			if (umoven(tcp, args[i], fdsize, (char *) fds) < 0)
 			{
 				fprintf(stderr, "umoven() failed\n");
 				continue;
 			}

 			for (j = 0; j < nfds; ++j)
 				if (FD_ISSET(j, fds) && fdmatch(tcp, j))
 				{
 					free(fds);
 					return 1;
 				}
 		}
 		free(fds);
 		return 0;
 	}

 	if (s->sys_func == sys_poll ||
 	    s->sys_func == sys_ppoll)
 	{
 		struct pollfd fds;
 		unsigned nfds;
 		unsigned long start, cur, end;

 		start = tcp->u_arg[0];
 		nfds = tcp->u_arg[1];

 		end = start + sizeof(fds) * nfds;

 		if (nfds == 0 || end < start)
 			return 0;

 		for (cur = start; cur < end; cur += sizeof(fds))
 			if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
 			    && fdmatch(tcp, fds.fd))
 				return 1;

 		return 0;
 	}

 	if (s->sys_func == printargs ||
 	    s->sys_func == sys_pipe ||
 	    s->sys_func == sys_pipe2 ||
 	    s->sys_func == sys_eventfd2 ||
 	    s->sys_func == sys_eventfd ||
 	    s->sys_func == sys_inotify_init1 ||
 	    s->sys_func == sys_timerfd_create ||
 	    s->sys_func == sys_timerfd_settime ||
 	    s->sys_func == sys_timerfd_gettime ||
 	    s->sys_func == sys_epoll_create ||
 	    !strcmp(s->sys_name, "fanotify_init"))
 	{
 		/*
 		 * These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
 		 * don't have any file descriptor or path args to test.
 		 */
 		return 0;
 	}
 #else
 #warning "path tracing only using arg[0]"
 #endif

 	/*
 	 * Our fallback position for calls that haven't already
 	 * been handled is to just check arg[0].
 	 */

 	if (s->sys_flags & TRACE_FILE)
 		return upathmatch(tcp, tcp->u_arg[0]);

 	if (s->sys_flags & TRACE_DESC)
 		return fdmatch(tcp, tcp->u_arg[0]);

 	return 0;
 }
	/*
	* Copyright (c) 2011, Comtrol Corp.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	*/

	#include "defs.h"

	#include <ctype.h>
	#include <limits.h>

	#ifdef HAVE_POLL_H
	#include <poll.h>
	#endif
	#ifdef HAVE_SYS_POLL_H
	#include <sys/poll.h>
	#endif

	#include "syscall.h"

	#define NumElem(a) (int)(sizeof(a) / sizeof((a)[0]))

	#define MAXSELECTED 256 /* max number of "selected" paths */
	static const char selected[MAXSELECTED]; / paths selected for tracing */

	/*
	* Return true if specified path matches one that we're tracing.
	*/
	static int
	pathmatch(const char *path)
	{
	int i;

	for (i = 0; i < NumElem(selected); ++i)
	{
	if (selected[i] == NULL)
	return 0;
	if (!strcmp(path, selected[i]))
	return 1;
	}
	return 0;
	}

	/*
	* Return true if specified path (in user-space) matches.
	*/
	static int
	upathmatch(struct tcb *tcp, unsigned long upath)
	{
	char path[PATH_MAX + 1];

	return umovestr(tcp, upath, sizeof path, path) == 0 &&
	pathmatch(path);
	}

	/*
	* Return true if specified fd maps to a path we're tracing.
	*/
	static int
	fdmatch(struct tcb *tcp, int fd)
	{
	const char *path = getfdpath(tcp, fd);

	return path && pathmatch(path);
	}

	/*
	* Add a path to the set we're tracing.
	* Secifying NULL will delete all paths.
	*/
	static int
	storepath(const char *path)
	{
	int i;

	if (path == NULL)
	{
	for (i = 0; i < NumElem(selected); ++i)
	if (selected[i])
	{
	free((char *) selected[i]);
	selected[i] = NULL;
	}
	return 0;
	}

	for (i = 0; i < NumElem(selected); ++i)
	if (!selected[i])
	{
	selected[i] = path;
	return 0;
	}

	fprintf(stderr, "Max trace paths exceeded, only using first %d\n",
	NumElem(selected));
	return -1;
	}

	/*
	* Get path associated with fd.
	*/
	const char getfdpath(struct tcb tcp, int fd)
	{
	#ifdef LINUX
	static char path[PATH_MAX+1];
	char linkpath[64];
	ssize_t n;

	if (fd < 0)
	return NULL;

	snprintf(linkpath, sizeof linkpath, "/proc/%d/fd/%d", tcp->pid, fd);
	n = readlink(linkpath, path, (sizeof path) - 1);
	if (n <= 0)
	return NULL;
	path[n] = '\0';
	return path;
	#else
	return NULL;
	#endif
	}

	/*
	* Add a path to the set we're tracing. Also add the canonicalized
	* version of the path. Secifying NULL will delete all paths.
	*/
	int
	pathtrace_select(const char *path)
	{
	char *rpath;

	if (path == NULL)
	return storepath(path);

	if (storepath(path))
	return -1;

	rpath = realpath(path, NULL);

	if (rpath == NULL)
	return 0;

	/* if realpath and specified path are same, we're done */
	if (!strcmp(path, rpath))
	{
	free(rpath);
	return 0;
	}

	fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
	path, rpath);
	return storepath(rpath);
	}

	/*
	* Return true if syscall accesses a selected path
	* (or if no paths have been specified for tracing).
	*/
	int
	pathtrace_match(struct tcb *tcp)
	{
	const struct sysent *s;

	if (selected[0] == NULL)
	return 1;

	s = &sysent[tcp->scno];

	if (!(s->sys_flags & (TRACE_FILE \| TRACE_DESC)))
	return 0;

	/*
	* Check for special cases where we need to do something
	* other than test arg[0].
	*/

	#ifdef LINUX

	if (s->sys_func == sys_dup2 \|\|
	s->sys_func == sys_dup3 \|\|
	s->sys_func == sys_sendfile \|\|
	s->sys_func == sys_sendfile64 \|\|
	!strcmp(s->sys_name, "tee"))
	{
	/* fd, fd */
	return fdmatch(tcp, tcp->u_arg[0]) \|\|
	fdmatch(tcp, tcp->u_arg[1]);
	}

	if (s->sys_func == sys_inotify_add_watch \|\|
	s->sys_func == sys_faccessat \|\|
	s->sys_func == sys_fchmodat \|\|
	s->sys_func == sys_futimesat \|\|
	s->sys_func == sys_mkdirat \|\|
	s->sys_func == sys_unlinkat \|\|
	s->sys_func == sys_newfstatat \|\|
	s->sys_func == sys_mknodat \|\|
	s->sys_func == sys_openat \|\|
	s->sys_func == sys_readlinkat \|\|
	s->sys_func == sys_utimensat \|\|
	s->sys_func == sys_fchownat \|\|
	s->sys_func == sys_pipe2)
	{
	/* fd, path */
	return fdmatch(tcp, tcp->u_arg[0]) \|\|
	upathmatch(tcp, tcp->u_arg[1]);
	}

	if (s->sys_func == sys_link \|\|
	s->sys_func == sys_pivotroot \|\|
	s->sys_func == sys_rename \|\|
	s->sys_func == sys_symlink \|\|
	s->sys_func == sys_mount)
	{
	/* path, path */
	return upathmatch(tcp, tcp->u_arg[0]) \|\|
	upathmatch(tcp, tcp->u_arg[1]);
	}

	if (s->sys_func == sys_renameat \|\|
	s->sys_func == sys_linkat)
	{
	/* fd, path, fd, path */
	return fdmatch(tcp, tcp->u_arg[0]) \|\|
	fdmatch(tcp, tcp->u_arg[2]) \|\|
	upathmatch(tcp, tcp->u_arg[1]) \|\|
	upathmatch(tcp, tcp->u_arg[3]);
	}

	if (s->sys_func == sys_old_mmap \|\| s->sys_func == sys_mmap)
	{
	/* x, x, x, x, fd */
	return fdmatch(tcp, tcp->u_arg[4]);
	}

	if (s->sys_func == sys_symlinkat)
	{
	/* path, fd, path */
	return fdmatch(tcp, tcp->u_arg[1]) \|\|
	upathmatch(tcp, tcp->u_arg[0]) \|\|
	upathmatch(tcp, tcp->u_arg[2]);
	}

	if (!strcmp(s->sys_name, "splice"))
	{
	/* fd, x, fd, x, x */
	return fdmatch(tcp, tcp->u_arg[0]) \|\|
	fdmatch(tcp, tcp->u_arg[2]);
	}

	if (s->sys_func == sys_epoll_ctl)
	{
	/* x, x, fd, x */
	return fdmatch(tcp, tcp->u_arg[2]);
	}

	if (s->sys_func == sys_select \|\|
	s->sys_func == sys_oldselect \|\|
	s->sys_func == sys_pselect6)
	{
	int i, j, nfds;
	long *args, oldargs[5];
	unsigned fdsize;
	fd_set *fds;

	if (s->sys_func == sys_oldselect)
	{
	if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
	(char*) oldargs) < 0)
	{
	fprintf(stderr, "umoven() failed\n");
	return 0;
	}
	args = oldargs;
	} else
	args = tcp->u_arg;

	nfds = args[0];
	fdsize = ((((nfds + 7) / 8) + sizeof(long) - 1)
	& -sizeof(long));
	fds = malloc(fdsize);

	if (fds == NULL)
	{
	fprintf(stderr, "out of memory\n");
	return 0;
	}

	for (i = 1; i <= 3; ++i)
	{
	if (args[i] == 0)
	continue;

	if (umoven(tcp, args[i], fdsize, (char *) fds) < 0)
	{
	fprintf(stderr, "umoven() failed\n");
	continue;
	}

	for (j = 0; j < nfds; ++j)
	if (FD_ISSET(j, fds) && fdmatch(tcp, j))
	{
	free(fds);
	return 1;
	}
	}
	free(fds);
	return 0;
	}

	if (s->sys_func == sys_poll \|\|
	s->sys_func == sys_ppoll)
	{
	struct pollfd fds;
	unsigned nfds;
	unsigned long start, cur, end;

	start = tcp->u_arg[0];
	nfds = tcp->u_arg[1];

	end = start + sizeof(fds) * nfds;

	if (nfds == 0 \|\| end < start)
	return 0;

	for (cur = start; cur < end; cur += sizeof(fds))
	if ((umoven(tcp, cur, sizeof fds, (char *) &fds) == 0)
	&& fdmatch(tcp, fds.fd))
	return 1;

	return 0;
	}

	if (s->sys_func == printargs \|\|
	s->sys_func == sys_pipe \|\|
	s->sys_func == sys_pipe2 \|\|
	s->sys_func == sys_eventfd2 \|\|
	s->sys_func == sys_eventfd \|\|
	s->sys_func == sys_inotify_init1 \|\|
	s->sys_func == sys_timerfd_create \|\|
	s->sys_func == sys_timerfd_settime \|\|
	s->sys_func == sys_timerfd_gettime \|\|
	s->sys_func == sys_epoll_create \|\|
	!strcmp(s->sys_name, "fanotify_init"))
	{
	/*
	* These have TRACE_FILE or TRACE_DESCRIPTOR set, but they
	* don't have any file descriptor or path args to test.
	*/
	return 0;
	}
	#else
	#warning "path tracing only using arg[0]"
	#endif

	/*
	* Our fallback position for calls that haven't already
	* been handled is to just check arg[0].
	*/

	if (s->sys_flags & TRACE_FILE)
	return upathmatch(tcp, tcp->u_arg[0]);

	if (s->sys_flags & TRACE_DESC)
	return fdmatch(tcp, tcp->u_arg[0]);

	return 0;
	}