A test suite that calls unsafe_symlink() directly to see how it

[rsync/rsync.git] / util.c

/*  -*- c-file-style: "linux" -*-
 * 
 * Copyright (C) 1996-2000 by Andrew Tridgell 
 * Copyright (C) Paul Mackerras 1996
 * Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/**
 * @file
 *
 * Utilities used in rsync 
 **/

#include "rsync.h"

extern int verbose;

int sanitize_paths = 0;



/**
 * Set a fd into nonblocking mode
 **/
void set_nonblocking(int fd)
{
	int val;

	if ((val = fcntl(fd, F_GETFL, 0)) == -1)
		return;
	if (!(val & NONBLOCK_FLAG)) {
		val |= NONBLOCK_FLAG;
		fcntl(fd, F_SETFL, val);
	}
}

/**
 * Set a fd into blocking mode
 **/
void set_blocking(int fd)
{
	int val;

	if ((val = fcntl(fd, F_GETFL, 0)) == -1)
		return;
	if (val & NONBLOCK_FLAG) {
		val &= ~NONBLOCK_FLAG;
		fcntl(fd, F_SETFL, val);
	}
}


/**
 * Create a file descriptor pair - like pipe() but use socketpair if
 * possible (because of blocking issues on pipes).
 * 
 * Always set non-blocking.
 */
int fd_pair(int fd[2])
{
	int ret;

#if HAVE_SOCKETPAIR
	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
#else
	ret = pipe(fd);
#endif

	if (ret == 0) {
		set_nonblocking(fd[0]);
		set_nonblocking(fd[1]);
	}

	return ret;
}


void print_child_argv(char **cmd)
{
	rprintf(FINFO, "opening connection using ");
	for (; *cmd; cmd++) {
		/* Look for characters that ought to be quoted.  This
		* is not a great quoting algorithm, but it's
		* sufficient for a log message. */
		if (strspn(*cmd, "abcdefghijklmnopqrstuvwxyz"
			   "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
			   "0123456789"
			   ",.-_=+@/") != strlen(*cmd)) {
			rprintf(FINFO, "\"%s\" ", *cmd);
		} else {
			rprintf(FINFO, "%s ", *cmd);
		}
	}
	rprintf(FINFO, "\n");
}


void out_of_memory(char *str)
{
  rprintf(FERROR,"ERROR: out of memory in %s\n",str);
  exit_cleanup(RERR_MALLOC);
}

void overflow(char *str)
{
  rprintf(FERROR,"ERROR: buffer overflow in %s\n",str);
  exit_cleanup(RERR_MALLOC);
}



int set_modtime(char *fname, time_t modtime)
{
	extern int dry_run;
	if (dry_run)
		return 0;

	if (verbose > 2) {
		rprintf(FINFO, "set modtime of %s to (%ld) %s",
			fname, (long) modtime,
			asctime(localtime(&modtime)));
	}
	
	{
#ifdef HAVE_UTIMBUF
		struct utimbuf tbuf;  
		tbuf.actime = time(NULL);
		tbuf.modtime = modtime;
		return utime(fname,&tbuf);
#elif defined(HAVE_UTIME)
		time_t t[2];
		t[0] = time(NULL);
		t[1] = modtime;
		return utime(fname,t);
#else
		struct timeval t[2];
		t[0].tv_sec = time(NULL);
		t[0].tv_usec = 0;
		t[1].tv_sec = modtime;
		t[1].tv_usec = 0;
		return utimes(fname,t);
#endif
	}
}


/**
   Create any necessary directories in fname. Unfortunately we don't know
   what perms to give the directory when this is called so we need to rely
   on the umask
**/
int create_directory_path(char *fname, int base_umask)
{
	char *p;

	while (*fname == '/') fname++;
	while (strncmp(fname,"./",2)==0) fname += 2;

	p = fname;
	while ((p=strchr(p,'/'))) {
		*p = 0;
		do_mkdir(fname, 0777 & ~base_umask); 
		*p = '/';
		p++;
	}
	return 0;
}


/**
 * Write @p len bytes at @p ptr to descriptor @p desc, retrying if
 * interrupted.
 *
 * @retval len upon success
 *
 * @retval <0 write's (negative) error code
 *
 * Derived from GNU C's cccp.c.
 */
static int full_write(int desc, char *ptr, size_t len)
{
	int total_written;
	
	total_written = 0;
	while (len > 0) {
		int written = write (desc, ptr, len);
		if (written < 0)  {
#ifdef EINTR
			if (errno == EINTR)
				continue;
#endif
			return written;
		}
		total_written += written;
		ptr += written;
		len -= written;
	}
	return total_written;
}


/**
 * Read @p len bytes at @p ptr from descriptor @p desc, retrying if
 * interrupted.
 *
 * @retval >0 the actual number of bytes read
 *
 * @retval 0 for EOF
 *
 * @retval <0 for an error.
 *
 * Derived from GNU C's cccp.c. */
static int safe_read(int desc, char *ptr, size_t len)
{
	int n_chars;
 
	if (len == 0)
		return len;
 
#ifdef EINTR
	do {
		n_chars = read(desc, ptr, len);
	} while (n_chars < 0 && errno == EINTR);
#else
	n_chars = read(desc, ptr, len);
#endif
 
	return n_chars;
}


/** Copy a file.
 *
 * This is used in conjunction with the --temp-dir option */
int copy_file(char *source, char *dest, mode_t mode)
{
	int ifd;
	int ofd;
	char buf[1024 * 8];
	int len;   /* Number of bytes read into `buf'. */

	ifd = do_open(source, O_RDONLY, 0);
	if (ifd == -1) {
		rprintf(FERROR,"open %s: %s\n",
			source,strerror(errno));
		return -1;
	}

	if (robust_unlink(dest) && errno != ENOENT) {
		rprintf(FERROR,"unlink %s: %s\n",
			dest,strerror(errno));
		return -1;
	}

	ofd = do_open(dest, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, mode);
	if (ofd == -1) {
		rprintf(FERROR,"open %s: %s\n",
			dest,strerror(errno));
		close(ifd);
		return -1;
	}

	while ((len = safe_read(ifd, buf, sizeof(buf))) > 0) {
		if (full_write(ofd, buf, len) < 0) {
			rprintf(FERROR,"write %s: %s\n",
				dest,strerror(errno));
			close(ifd);
			close(ofd);
			return -1;
		}
	}

	close(ifd);
	close(ofd);

	if (len < 0) {
		rprintf(FERROR,"read %s: %s\n",
			source,strerror(errno));
		return -1;
	}

	return 0;
}

/* MAX_RENAMES should be 10**MAX_RENAMES_DIGITS */
#define MAX_RENAMES_DIGITS 3
#define MAX_RENAMES 1000

/**
 * 
  Robust unlink: some OS'es (HPUX) refuse to unlink busy files, so
  rename to <path>/.rsyncNNN instead.
  
  Note that successive rsync runs will shuffle the filenames around a
  bit as long as the file is still busy; this is because this function
  does not know if the unlink call is due to a new file coming in, or
  --delete trying to remove old .rsyncNNN files, hence it renames it
  each time.
*/
int robust_unlink(char *fname)
{
#ifndef ETXTBSY
	return do_unlink(fname);
#else
	static int counter = 1;
	int rc, pos, start;
	char path[MAXPATHLEN];

	rc = do_unlink(fname);
	if ((rc == 0) || (errno != ETXTBSY))
		return rc;

	strlcpy(path, fname, MAXPATHLEN);

	pos = strlen(path);
	while((path[--pos] != '/') && (pos >= 0))
		;
	++pos;
	strlcpy(&path[pos], ".rsync", MAXPATHLEN-pos);
	pos += sizeof(".rsync")-1;

	if (pos > (MAXPATHLEN-MAX_RENAMES_DIGITS-1)) {
		errno = ETXTBSY;
		return -1;
	}

	/* start where the last one left off to reduce chance of clashes */
	start = counter;
	do {
		sprintf(&path[pos], "%03d", counter);
		if (++counter >= MAX_RENAMES)
			counter = 1;
	} while (((rc = access(path, 0)) == 0) && (counter != start));

	if (verbose > 0)
		rprintf(FINFO,"renaming %s to %s because of text busy\n",
					    fname, path);

	/* maybe we should return rename()'s exit status? Nah. */
	if (do_rename(fname, path) != 0) {
		errno = ETXTBSY;
		return -1;
	}
	return 0;
#endif
}

int robust_rename(char *from, char *to)
{
#ifndef ETXTBSY
	return do_rename(from, to);
#else
	int rc = do_rename(from, to);
	if ((rc == 0) || (errno != ETXTBSY))
		return rc;
	if (robust_unlink(to) != 0)
		return -1;
	return do_rename(from, to);
#endif
}


static pid_t all_pids[10];
static int num_pids;

/** Fork and record the pid of the child. **/
pid_t do_fork(void)
{
	pid_t newpid = fork();
	
	if (newpid != 0  &&  newpid != -1) {
		all_pids[num_pids++] = newpid;
	}
	return newpid;
}

/**
 * Kill all children.
 *
 * @todo It would be kind of nice to make sure that they are actually
 * all our children before we kill them, because their pids may have
 * been recycled by some other process.  Perhaps when we wait for a
 * child, we should remove it from this array.  Alternatively we could
 * perhaps use process groups, but I think that would not work on
 * ancient Unix versions that don't support them.
 **/
void kill_all(int sig)
{
	int i;

	for (i = 0; i < num_pids; i++) {
		/* Let's just be a little careful where we
		 * point that gun, hey?  See kill(2) for the
		 * magic caused by negative values. */
		pid_t p = all_pids[i];

		if (p == getpid())
			continue;
		if (p <= 0)
			continue;

		kill(p, sig);
	}
}


/** Turn a user name into a uid */
int name_to_uid(char *name, uid_t *uid)
{
	struct passwd *pass;
	if (!name || !*name) return 0;
	pass = getpwnam(name);
	if (pass) {
		*uid = pass->pw_uid;
		return 1;
	}
	return 0;
}

/** Turn a group name into a gid */
int name_to_gid(char *name, gid_t *gid)
{
	struct group *grp;
	if (!name || !*name) return 0;
	grp = getgrnam(name);
	if (grp) {
		*gid = grp->gr_gid;
		return 1;
	}
	return 0;
}


/** Lock a byte range in a open file */
int lock_range(int fd, int offset, int len)
{
	struct flock lock;

	lock.l_type = F_WRLCK;
	lock.l_whence = SEEK_SET;
	lock.l_start = offset;
	lock.l_len = len;
	lock.l_pid = 0;
	
	return fcntl(fd,F_SETLK,&lock) == 0;
}


static void glob_expand_one(char *s, char **argv, int *argc, int maxargs)
{
#if !(defined(HAVE_GLOB) && defined(HAVE_GLOB_H))
	if (!*s) s = ".";
	argv[*argc] = strdup(s);
	(*argc)++;
	return;
#else
	extern int sanitize_paths;
	glob_t globbuf;
	int i;

	if (!*s) s = ".";

	argv[*argc] = strdup(s);
	if (sanitize_paths) {
		sanitize_path(argv[*argc], NULL);
	}

	memset(&globbuf, 0, sizeof(globbuf));
	glob(argv[*argc], 0, NULL, &globbuf);
	if (globbuf.gl_pathc == 0) {
		(*argc)++;
		globfree(&globbuf);
		return;
	}
	for (i=0; i<(maxargs - (*argc)) && i < (int) globbuf.gl_pathc;i++) {
		if (i == 0) free(argv[*argc]);
		argv[(*argc) + i] = strdup(globbuf.gl_pathv[i]);
		if (!argv[(*argc) + i]) out_of_memory("glob_expand");
	}
	globfree(&globbuf);
	(*argc) += i;
#endif
}

void glob_expand(char *base1, char **argv, int *argc, int maxargs)
{
	char *s = argv[*argc];
	char *p, *q;
	char *base = base1;

	if (!s || !*s) return;

	if (strncmp(s, base, strlen(base)) == 0) {
		s += strlen(base);
	}

	s = strdup(s);
	if (!s) out_of_memory("glob_expand");

	if (asprintf(&base," %s/", base1) <= 0) out_of_memory("glob_expand");

	q = s;
	while ((p = strstr(q,base)) && ((*argc) < maxargs)) {
		/* split it at this point */
		*p = 0;
		glob_expand_one(q, argv, argc, maxargs);
		q = p+strlen(base);
	}

	if (*q && (*argc < maxargs)) glob_expand_one(q, argv, argc, maxargs);

	free(s);
	free(base);
}

/**
 * Convert a string to lower case
 **/
void strlower(char *s)
{
	while (*s) {
		if (isupper(*s)) *s = tolower(*s);
		s++;
	}
}

void *Realloc(void *p, int size)
{
	if (!p) return (void *)malloc(size);
	return (void *)realloc(p, size);
}


void clean_fname(char *name)
{
	char *p;
	int l;
	int modified = 1;

	if (!name) return;

	while (modified) {
		modified = 0;

		if ((p=strstr(name,"/./"))) {
			modified = 1;
			while (*p) {
				p[0] = p[2];
				p++;
			}
		}

		if ((p=strstr(name,"//"))) {
			modified = 1;
			while (*p) {
				p[0] = p[1];
				p++;
			}
		}

		if (strncmp(p=name,"./",2) == 0) {      
			modified = 1;
			do {
				p[0] = p[2];
			} while (*p++);
		}

		l = strlen(p=name);
		if (l > 1 && p[l-1] == '/') {
			modified = 1;
			p[l-1] = 0;
		}
	}
}

/**
 * Make path appear as if a chroot had occurred:
 *
 *    1. remove leading "/" (or replace with "." if at end)
 *    2. remove leading ".." components (except those allowed by "reldir")
 *    3. delete any other "<dir>/.." (recursively)
 *
 * Can only shrink paths, so sanitizes in place.
 *
 * While we're at it, remove double slashes and "." components like
 *   clean_fname does(), but DON'T remove a trailing slash because that
 *   is sometimes significant on command line arguments.
 *
 * If "reldir" is non-null, it is a sanitized directory that the path will be
 *    relative to, so allow as many ".." at the beginning of the path as
 *    there are components in reldir.  This is used for symbolic link targets.
 *    If reldir is non-null and the path began with "/", to be completely like
 *    a chroot we should add in depth levels of ".." at the beginning of the
 *    path, but that would blow the assumption that the path doesn't grow and
 *    it is not likely to end up being a valid symlink anyway, so just do
 *    the normal removal of the leading "/" instead.
 *
 * Contributed by Dave Dykstra <dwd@bell-labs.com>
 */
void sanitize_path(char *p, char *reldir)
{
	char *start, *sanp;
	int depth = 0;
	int allowdotdot = 0;

	if (reldir) {
		depth++;
		while (*reldir) {
			if (*reldir++ == '/') {
				depth++;
			}
		}
	}
	start = p;
	sanp = p;
	while (*p == '/') {
		/* remove leading slashes */
		p++;
	}
	while (*p != '\0') {
		/* this loop iterates once per filename component in p.
		 * both p (and sanp if the original had a slash) should
		 * always be left pointing after a slash
		 */
		if ((*p == '.') && ((*(p+1) == '/') || (*(p+1) == '\0'))) {
			/* skip "." component */
			while (*++p == '/') {
				/* skip following slashes */
				;
			}
			continue;
		}
		allowdotdot = 0;
		if ((*p == '.') && (*(p+1) == '.') &&
			    ((*(p+2) == '/') || (*(p+2) == '\0'))) {
			/* ".." component followed by slash or end */
			if ((depth > 0) && (sanp == start)) {
				/* allow depth levels of .. at the beginning */
				--depth;
				allowdotdot = 1;
			} else {
				p += 2;
				if (*p == '/')
					p++;
				if (sanp != start) {
					/* back up sanp one level */
					--sanp; /* now pointing at slash */
					while ((sanp > start) && (*(sanp - 1) != '/')) {
						/* skip back up to slash */
						sanp--;
					}
				}
				continue;
			}
		}
		while (1) {
			/* copy one component through next slash */
			*sanp++ = *p++;
			if ((*p == '\0') || (*(p-1) == '/')) {
				while (*p == '/') {
					/* skip multiple slashes */
					p++;
				}
				break;
			}
		}
		if (allowdotdot) {
			/* move the virtual beginning to leave the .. alone */
			start = sanp;
		}
	}
	if ((sanp == start) && !allowdotdot) {
		/* ended up with nothing, so put in "." component */
		/*
		 * note that the !allowdotdot doesn't prevent this from
		 *  happening in all allowed ".." situations, but I didn't
		 *  think it was worth putting in an extra variable to ensure
		 *  it since an extra "." won't hurt in those situations.
		 */
		*sanp++ = '.';
	}
	*sanp = '\0';
}


static char curr_dir[MAXPATHLEN];

/** like chdir() but can be reversed with pop_dir() if save is set. It
   is also much faster as it remembers where we have been */
char *push_dir(char *dir, int save)
{
	char *ret = curr_dir;
	static int initialised;

	if (!initialised) {
		initialised = 1;
		getcwd(curr_dir, sizeof(curr_dir)-1);
	}

	if (!dir) return NULL; /* this call was probably just to initialize */

	if (chdir(dir)) return NULL;

	if (save) {
		ret = strdup(curr_dir);
	}

	if (*dir == '/') {
		strlcpy(curr_dir, dir, sizeof(curr_dir));
	} else {
		strlcat(curr_dir,"/", sizeof(curr_dir));
		strlcat(curr_dir,dir, sizeof(curr_dir));
	}

	clean_fname(curr_dir);

	return ret;
}

/** Reverse a push_dir call */
int pop_dir(char *dir)
{
	int ret;

	ret = chdir(dir);
	if (ret) {
		free(dir);
		return ret;
	}

	strlcpy(curr_dir, dir, sizeof(curr_dir));

	free(dir);

	return 0;
}

/** We need to supply our own strcmp function for file list comparisons
   to ensure that signed/unsigned usage is consistent between machines. */
int u_strcmp(const char *cs1, const char *cs2)
{
	const uchar *s1 = (const uchar *)cs1;
	const uchar *s2 = (const uchar *)cs2;

	while (*s1 && *s2 && (*s1 == *s2)) {
		s1++; s2++;
	}
	
	return (int)*s1 - (int)*s2;
}



/**
 * Determine if a symlink points outside the current directory tree.
 * This is considered "unsafe" because e.g. when mirroring somebody
 * else's machine it might allow them to establish a symlink to
 * /etc/passwd, and then read it through a web server.
 *
 * @param dest Target of the symlink in question.
 *
 * @param src Top source directory currently applicable.  Basically this
 * is the first parameter to rsync in a simple invocation, but it's
 * modified by flist.c in slightly complex ways.
 *
 * @retval True if unsafe
 * @retval False is unsafe
 **/
int unsafe_symlink(char *dest, char *src)
{
	char *tok;
	int depth = 0;

	/* all absolute and null symlinks are unsafe */
	if (!dest || !(*dest) || (*dest == '/')) return 1;

	src = strdup(src);
	if (!src) out_of_memory("unsafe_symlink");

	/* find out what our safety margin is */
	for (tok=strtok(src,"/"); tok; tok=strtok(NULL,"/")) {
		if (strcmp(tok,"..") == 0) {
			depth=0;
		} else if (strcmp(tok,".") == 0) {
			/* nothing */
		} else {
			depth++;
		}
	}
	free(src);

	/* drop by one to account for the filename portion */
	depth--;

	dest = strdup(dest);
	if (!dest) out_of_memory("unsafe_symlink");

	for (tok=strtok(dest,"/"); tok; tok=strtok(NULL,"/")) {
		if (strcmp(tok,"..") == 0) {
			depth--;
		} else if (strcmp(tok,".") == 0) {
			/* nothing */
		} else {
			depth++;
		}
		/* if at any point we go outside the current directory then
		   stop - it is unsafe */
		if (depth < 0) break;
	}

	free(dest);
	return (depth < 0);
}


/**
   Return the date and time as a string
*/
char *timestring(time_t t)
{
	static char TimeBuf[200];
	struct tm *tm = localtime(&t);

#ifdef HAVE_STRFTIME
	strftime(TimeBuf,sizeof(TimeBuf)-1,"%Y/%m/%d %T",tm);
#else
	strlcpy(TimeBuf, asctime(tm), sizeof(TimeBuf));
#endif

	if (TimeBuf[strlen(TimeBuf)-1] == '\n') {
		TimeBuf[strlen(TimeBuf)-1] = 0;
	}

	return(TimeBuf);
}


/**
 * Sleep for a specified number of milliseconds.
 *
 * Always returns TRUE.  (In the future it might return FALSE if
 * interrupted.)
 **/
int msleep(int t)
{
	int tdiff=0;
	struct timeval tval,t1,t2;  

	gettimeofday(&t1, NULL);
	gettimeofday(&t2, NULL);
  
	while (tdiff < t) {
		tval.tv_sec = (t-tdiff)/1000;
		tval.tv_usec = 1000*((t-tdiff)%1000);
 
		errno = 0;
		select(0,NULL,NULL, NULL, &tval);

		gettimeofday(&t2, NULL);
		tdiff = (t2.tv_sec - t1.tv_sec)*1000 + 
			(t2.tv_usec - t1.tv_usec)/1000;
	}

	return True;
}


/**
 * Determine if two file modification times are equivalent (either
 * exact or in the modification timestamp window established by
 * --modify-window).
 *
 * @retval 0 if the times should be treated as the same
 *
 * @retval +1 if the first is later
 *
 * @retval -1 if the 2nd is later
 **/
int cmp_modtime(time_t file1, time_t file2)
{
	extern int modify_window;

	if (file2 > file1) {
		if (file2 - file1 <= modify_window) return 0;
		return -1;
	}
	if (file1 - file2 <= modify_window) return 0;
	return 1;
}


#ifdef __INSURE__XX
#include <dlfcn.h>

/**
   This routine is a trick to immediately catch errors when debugging
   with insure. A xterm with a gdb is popped up when insure catches
   a error. It is Linux specific.
**/
int _Insure_trap_error(int a1, int a2, int a3, int a4, int a5, int a6)
{
	static int (*fn)();
	int ret;
	char *cmd;

	asprintf(&cmd, "/usr/X11R6/bin/xterm -display :0 -T Panic -n Panic -e /bin/sh -c 'cat /tmp/ierrs.*.%d ; gdb /proc/%d/exe %d'", 
		getpid(), getpid(), getpid());

	if (!fn) {
		static void *h;
		h = dlopen("/usr/local/parasoft/insure++lite/lib.linux2/libinsure.so", RTLD_LAZY);
		fn = dlsym(h, "_Insure_trap_error");
	}

	ret = fn(a1, a2, a3, a4, a5, a6);

	system(cmd);

	free(cmd);

	return ret;
}
#endif