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util.c
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util.c
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/*
* Utility routines used in rsync.
*
* Copyright (C) 1996-2000 Andrew Tridgell
* Copyright (C) 1996 Paul Mackerras
* Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
* Copyright (C) 2003-2009 Wayne Davison
*
* 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 3 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, visit the http://fsf.org website.
*/
#include "rsync.h"
#include "ifuncs.h"
#include "itypes.h"
#include "inums.h"
extern int module_id;
extern int modify_window;
extern int relative_paths;
extern int preserve_times;
extern int preserve_xattrs;
extern char *module_dir;
extern unsigned int module_dirlen;
extern char *partial_dir;
extern filter_rule_list daemon_filter_list;
int sanitize_paths = 0;
char curr_dir[MAXPATHLEN];
unsigned int curr_dir_len;
int curr_dir_depth; /* This is only set for a sanitizing daemon. */
/* Set a fd into nonblocking mode. */
void set_nonblocking(int fd)
{
int val;
if ((val = fcntl(fd, F_GETFL)) == -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)) == -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;
#ifdef 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(const char *prefix, char **cmd)
{
rprintf(FCLIENT, "%s ", prefix);
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(FCLIENT, "\"%s\" ", *cmd);
} else {
rprintf(FCLIENT, "%s ", *cmd);
}
}
rprintf(FCLIENT, "\n");
}
NORETURN void out_of_memory(const char *str)
{
rprintf(FERROR, "ERROR: out of memory in %s [%s]\n", str, who_am_i());
exit_cleanup(RERR_MALLOC);
}
NORETURN void overflow_exit(const char *str)
{
rprintf(FERROR, "ERROR: buffer overflow in %s [%s]\n", str, who_am_i());
exit_cleanup(RERR_MALLOC);
}
/* This returns 0 for success, 1 for a symlink if symlink time-setting
* is not possible, or -1 for any other error. */
int set_modtime(const char *fname, time_t modtime, uint32 mod_nsec, mode_t mode)
{
static int switch_step = 0;
if (DEBUG_GTE(TIME, 1)) {
rprintf(FINFO, "set modtime of %s to (%ld) %s",
fname, (long)modtime,
asctime(localtime(&modtime)));
}
switch (switch_step) {
#ifdef HAVE_UTIMENSAT
#include "case_N.h"
if (do_utimensat(fname, modtime, mod_nsec) == 0)
break;
if (errno != ENOSYS)
return -1;
switch_step++;
/* FALLTHROUGH */
#endif
#ifdef HAVE_LUTIMES
#include "case_N.h"
if (do_lutimes(fname, modtime, mod_nsec) == 0)
break;
if (errno != ENOSYS)
return -1;
switch_step++;
/* FALLTHROUGH */
#endif
#include "case_N.h"
switch_step++;
if (preserve_times & PRESERVE_LINK_TIMES) {
preserve_times &= ~PRESERVE_LINK_TIMES;
if (S_ISLNK(mode))
return 1;
}
/* FALLTHROUGH */
#include "case_N.h"
#ifdef HAVE_UTIMES
if (do_utimes(fname, modtime, mod_nsec) == 0)
break;
#else
if (do_utime(fname, modtime, mod_nsec) == 0)
break;
#endif
return -1;
}
return 0;
}
/* Create any necessary directories in fname. Any missing directories are
* created with default permissions. Returns < 0 on error, or the number
* of directories created. */
int make_path(char *fname, int flags)
{
char *end, *p;
int ret = 0;
if (flags & MKP_SKIP_SLASH) {
while (*fname == '/')
fname++;
}
while (*fname == '.' && fname[1] == '/')
fname += 2;
if (flags & MKP_DROP_NAME) {
end = strrchr(fname, '/');
if (!end)
return 0;
*end = '\0';
} else
end = fname + strlen(fname);
/* Try to find an existing dir, starting from the deepest dir. */
for (p = end; ; ) {
if (do_mkdir(fname, ACCESSPERMS) == 0) {
ret++;
break;
}
if (errno != ENOENT) {
if (errno != EEXIST)
ret = -ret - 1;
break;
}
while (1) {
if (p == fname) {
ret = -ret - 1;
goto double_break;
}
if (*--p == '/') {
if (p == fname) {
ret = -ret - 1; /* impossible... */
goto double_break;
}
*p = '\0';
break;
}
}
}
double_break:
/* Make all the dirs that we didn't find on the way here. */
while (p != end) {
*p = '/';
p += strlen(p);
if (ret < 0) /* Skip mkdir on error, but keep restoring the path. */
continue;
if (do_mkdir(fname, ACCESSPERMS) < 0)
ret = -ret - 1;
else
ret++;
}
if (flags & MKP_DROP_NAME)
*end = '/';
return ret;
}
/**
* 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.
*/
int full_write(int desc, const char *ptr, size_t len)
{
int total_written;
total_written = 0;
while (len > 0) {
int written = write(desc, ptr, len);
if (written < 0) {
if (errno == EINTR)
continue;
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;
do {
n_chars = read(desc, ptr, len);
} while (n_chars < 0 && errno == EINTR);
return n_chars;
}
/* Copy a file. If ofd < 0, copy_file unlinks and opens the "dest" file.
* Otherwise, it just writes to and closes the provided file descriptor.
* In either case, if --xattrs are being preserved, the dest file will
* have its xattrs set from the source file.
*
* This is used in conjunction with the --temp-dir, --backup, and
* --copy-dest options. */
int copy_file(const char *source, const char *dest, int ofd, mode_t mode)
{
int ifd;
char buf[1024 * 8];
int len; /* Number of bytes read into `buf'. */
if ((ifd = do_open(source, O_RDONLY, 0)) < 0) {
int save_errno = errno;
rsyserr(FERROR_XFER, errno, "open %s", full_fname(source));
errno = save_errno;
return -1;
}
if (ofd < 0) {
if (robust_unlink(dest) && errno != ENOENT) {
int save_errno = errno;
rsyserr(FERROR_XFER, errno, "unlink %s", full_fname(dest));
errno = save_errno;
return -1;
}
#ifdef SUPPORT_XATTRS
if (preserve_xattrs)
mode |= S_IWUSR;
#endif
mode &= INITACCESSPERMS;
if ((ofd = do_open(dest, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, mode)) < 0) {
int save_errno = errno;
rsyserr(FERROR_XFER, save_errno, "open %s", full_fname(dest));
close(ifd);
errno = save_errno;
return -1;
}
}
while ((len = safe_read(ifd, buf, sizeof buf)) > 0) {
if (full_write(ofd, buf, len) < 0) {
int save_errno = errno;
rsyserr(FERROR_XFER, errno, "write %s", full_fname(dest));
close(ifd);
close(ofd);
errno = save_errno;
return -1;
}
}
if (len < 0) {
int save_errno = errno;
rsyserr(FERROR_XFER, errno, "read %s", full_fname(source));
close(ifd);
close(ofd);
errno = save_errno;
return -1;
}
if (close(ifd) < 0) {
rsyserr(FWARNING, errno, "close failed on %s",
full_fname(source));
}
if (close(ofd) < 0) {
int save_errno = errno;
rsyserr(FERROR_XFER, errno, "close failed on %s",
full_fname(dest));
errno = save_errno;
return -1;
}
#ifdef SUPPORT_XATTRS
if (preserve_xattrs)
copy_xattrs(source, dest);
#endif
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(const 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;
if ((pos = strlcpy(path, fname, MAXPATHLEN)) >= MAXPATHLEN)
pos = MAXPATHLEN - 1;
while (pos > 0 && path[pos-1] != '/')
pos--;
pos += strlcpy(path+pos, ".rsync", MAXPATHLEN-pos);
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 {
snprintf(&path[pos], MAX_RENAMES_DIGITS+1, "%03d", counter);
if (++counter >= MAX_RENAMES)
counter = 1;
} while ((rc = access(path, 0)) == 0 && counter != start);
if (INFO_GTE(MISC, 1)) {
rprintf(FWARNING, "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
}
/* Returns 0 on successful rename, 1 if we successfully copied the file
* across filesystems, -2 if copy_file() failed, and -1 on other errors.
* If partialptr is not NULL and we need to do a copy, copy the file into
* the active partial-dir instead of over the destination file. */
int robust_rename(const char *from, const char *to, const char *partialptr,
int mode)
{
int tries = 4;
while (tries--) {
if (do_rename(from, to) == 0)
return 0;
switch (errno) {
#ifdef ETXTBSY
case ETXTBSY:
if (robust_unlink(to) != 0) {
errno = ETXTBSY;
return -1;
}
errno = ETXTBSY;
break;
#endif
case EXDEV:
if (partialptr) {
if (!handle_partial_dir(partialptr,PDIR_CREATE))
return -2;
to = partialptr;
}
if (copy_file(from, to, -1, mode) != 0)
return -2;
do_unlink(from);
return 1;
default:
return -1;
}
}
return -1;
}
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);
}
}
/** 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;
}
#define ENSURE_MEMSPACE(buf, type, sz, req) \
if ((req) > sz && !(buf = realloc_array(buf, type, sz = MAX(sz * 2, req)))) \
out_of_memory("glob_expand")
static inline void call_glob_match(const char *name, int len, int from_glob,
char *arg, int abpos, int fbpos);
static struct glob_data {
char *arg_buf, *filt_buf, **argv;
int absize, fbsize, maxargs, argc;
} glob;
static void glob_match(char *arg, int abpos, int fbpos)
{
int len;
char *slash;
while (*arg == '.' && arg[1] == '/') {
if (fbpos < 0) {
ENSURE_MEMSPACE(glob.filt_buf, char, glob.fbsize, glob.absize);
memcpy(glob.filt_buf, glob.arg_buf, abpos + 1);
fbpos = abpos;
}
ENSURE_MEMSPACE(glob.arg_buf, char, glob.absize, abpos + 3);
glob.arg_buf[abpos++] = *arg++;
glob.arg_buf[abpos++] = *arg++;
glob.arg_buf[abpos] = '\0';
}
if ((slash = strchr(arg, '/')) != NULL) {
*slash = '\0';
len = slash - arg;
} else
len = strlen(arg);
if (strpbrk(arg, "*?[")) {
struct dirent *di;
DIR *d;
if (!(d = opendir(abpos ? glob.arg_buf : ".")))
return;
while ((di = readdir(d)) != NULL) {
char *dname = d_name(di);
if (dname[0] == '.' && (dname[1] == '\0'
|| (dname[1] == '.' && dname[2] == '\0')))
continue;
if (!wildmatch(arg, dname))
continue;
call_glob_match(dname, strlen(dname), 1,
slash ? arg + len + 1 : NULL,
abpos, fbpos);
}
closedir(d);
} else {
call_glob_match(arg, len, 0,
slash ? arg + len + 1 : NULL,
abpos, fbpos);
}
if (slash)
*slash = '/';
}
static inline void call_glob_match(const char *name, int len, int from_glob,
char *arg, int abpos, int fbpos)
{
char *use_buf;
ENSURE_MEMSPACE(glob.arg_buf, char, glob.absize, abpos + len + 2);
memcpy(glob.arg_buf + abpos, name, len);
abpos += len;
glob.arg_buf[abpos] = '\0';
if (fbpos >= 0) {
ENSURE_MEMSPACE(glob.filt_buf, char, glob.fbsize, fbpos + len + 2);
memcpy(glob.filt_buf + fbpos, name, len);
fbpos += len;
glob.filt_buf[fbpos] = '\0';
use_buf = glob.filt_buf;
} else
use_buf = glob.arg_buf;
if (from_glob || (arg && len)) {
STRUCT_STAT st;
int is_dir;
if (do_stat(glob.arg_buf, &st) != 0)
return;
is_dir = S_ISDIR(st.st_mode) != 0;
if (arg && !is_dir)
return;
if (daemon_filter_list.head
&& check_filter(&daemon_filter_list, FLOG, use_buf, is_dir) < 0)
return;
}
if (arg) {
glob.arg_buf[abpos++] = '/';
glob.arg_buf[abpos] = '\0';
if (fbpos >= 0) {
glob.filt_buf[fbpos++] = '/';
glob.filt_buf[fbpos] = '\0';
}
glob_match(arg, abpos, fbpos);
} else {
ENSURE_MEMSPACE(glob.argv, char *, glob.maxargs, glob.argc + 1);
if (!(glob.argv[glob.argc++] = strdup(glob.arg_buf)))
out_of_memory("glob_match");
}
}
/* This routine performs wild-card expansion of the pathname in "arg". Any
* daemon-excluded files/dirs will not be matched by the wildcards. Returns 0
* if a wild-card string is the only returned item (due to matching nothing). */
int glob_expand(const char *arg, char ***argv_p, int *argc_p, int *maxargs_p)
{
int ret, save_argc;
char *s;
if (!arg) {
if (glob.filt_buf)
free(glob.filt_buf);
free(glob.arg_buf);
memset(&glob, 0, sizeof glob);
return -1;
}
if (sanitize_paths)
s = sanitize_path(NULL, arg, "", 0, SP_KEEP_DOT_DIRS);
else {
s = strdup(arg);
if (!s)
out_of_memory("glob_expand");
clean_fname(s, CFN_KEEP_DOT_DIRS
| CFN_KEEP_TRAILING_SLASH
| CFN_COLLAPSE_DOT_DOT_DIRS);
}
ENSURE_MEMSPACE(glob.arg_buf, char, glob.absize, MAXPATHLEN);
*glob.arg_buf = '\0';
glob.argc = save_argc = *argc_p;
glob.argv = *argv_p;
glob.maxargs = *maxargs_p;
ENSURE_MEMSPACE(glob.argv, char *, glob.maxargs, 100);
glob_match(s, 0, -1);
/* The arg didn't match anything, so add the failed arg to the list. */
if (glob.argc == save_argc) {
ENSURE_MEMSPACE(glob.argv, char *, glob.maxargs, glob.argc + 1);
glob.argv[glob.argc++] = s;
ret = 0;
} else {
free(s);
ret = 1;
}
*maxargs_p = glob.maxargs;
*argv_p = glob.argv;
*argc_p = glob.argc;
return ret;
}
/* This routine is only used in daemon mode. */
void glob_expand_module(char *base1, char *arg, char ***argv_p, int *argc_p, int *maxargs_p)
{
char *p, *s;
char *base = base1;
int base_len = strlen(base);
if (!arg || !*arg)
return;
if (strncmp(arg, base, base_len) == 0)
arg += base_len;
if (!(arg = strdup(arg)))
out_of_memory("glob_expand_module");
if (asprintf(&base," %s/", base1) <= 0)
out_of_memory("glob_expand_module");
base_len++;
for (s = arg; *s; s = p + base_len) {
if ((p = strstr(s, base)) != NULL)
*p = '\0'; /* split it at this point */
glob_expand(s, argv_p, argc_p, maxargs_p);
if (!p)
break;
}
free(arg);
free(base);
}
/**
* Convert a string to lower case
**/
void strlower(char *s)
{
while (*s) {
if (isUpper(s))
*s = toLower(s);
s++;
}
}
/* Join strings p1 & p2 into "dest" with a guaranteed '/' between them. (If
* p1 ends with a '/', no extra '/' is inserted.) Returns the length of both
* strings + 1 (if '/' was inserted), regardless of whether the null-terminated
* string fits into destsize. */
size_t pathjoin(char *dest, size_t destsize, const char *p1, const char *p2)
{
size_t len = strlcpy(dest, p1, destsize);
if (len < destsize - 1) {
if (!len || dest[len-1] != '/')
dest[len++] = '/';
if (len < destsize - 1)
len += strlcpy(dest + len, p2, destsize - len);
else {
dest[len] = '\0';
len += strlen(p2);
}
}
else
len += strlen(p2) + 1; /* Assume we'd insert a '/'. */
return len;
}
/* Join any number of strings together, putting them in "dest". The return
* value is the length of all the strings, regardless of whether the null-
* terminated whole fits in destsize. Your list of string pointers must end
* with a NULL to indicate the end of the list. */
size_t stringjoin(char *dest, size_t destsize, ...)
{
va_list ap;
size_t len, ret = 0;
const char *src;
va_start(ap, destsize);
while (1) {
if (!(src = va_arg(ap, const char *)))
break;
len = strlen(src);
ret += len;
if (destsize > 1) {
if (len >= destsize)
len = destsize - 1;
memcpy(dest, src, len);
destsize -= len;
dest += len;
}
}
*dest = '\0';
va_end(ap);
return ret;
}
int count_dir_elements(const char *p)
{
int cnt = 0, new_component = 1;
while (*p) {
if (*p++ == '/')
new_component = (*p != '.' || (p[1] != '/' && p[1] != '\0'));
else if (new_component) {
new_component = 0;
cnt++;
}
}
return cnt;
}
/* Turns multiple adjacent slashes into a single slash (possible exception:
* the preserving of two leading slashes at the start), drops all leading or
* interior "." elements unless CFN_KEEP_DOT_DIRS is flagged. Will also drop
* a trailing '.' after a '/' if CFN_DROP_TRAILING_DOT_DIR is flagged, removes
* a trailing slash (perhaps after removing the aforementioned dot) unless
* CFN_KEEP_TRAILING_SLASH is flagged, and will also collapse ".." elements
* (except at the start) if CFN_COLLAPSE_DOT_DOT_DIRS is flagged. If the
* resulting name would be empty, returns ".". */
unsigned int clean_fname(char *name, int flags)
{
char *limit = name - 1, *t = name, *f = name;
int anchored;
if (!name)
return 0;
if ((anchored = *f == '/') != 0) {
*t++ = *f++;
#ifdef __CYGWIN__
/* If there are exactly 2 slashes at the start, preserve
* them. Would break daemon excludes unless the paths are
* really treated differently, so used this sparingly. */
if (*f == '/' && f[1] != '/')
*t++ = *f++;
#endif
} else if (flags & CFN_KEEP_DOT_DIRS && *f == '.' && f[1] == '/') {
*t++ = *f++;
*t++ = *f++;
}
while (*f) {
/* discard extra slashes */
if (*f == '/') {
f++;
continue;
}
if (*f == '.') {
/* discard interior "." dirs */
if (f[1] == '/' && !(flags & CFN_KEEP_DOT_DIRS)) {
f += 2;
continue;
}
if (f[1] == '\0' && flags & CFN_DROP_TRAILING_DOT_DIR)
break;
/* collapse ".." dirs */
if (flags & CFN_COLLAPSE_DOT_DOT_DIRS
&& f[1] == '.' && (f[2] == '/' || !f[2])) {
char *s = t - 1;
if (s == name && anchored) {
f += 2;
continue;
}
while (s > limit && *--s != '/') {}
if (s != t - 1 && (s < name || *s == '/')) {
t = s + 1;
f += 2;
continue;
}
limit = t + 2;
}
}
while (*f && (*t++ = *f++) != '/') {}
}
if (t > name+anchored && t[-1] == '/' && !(flags & CFN_KEEP_TRAILING_SLASH))
t--;
if (t == name)
*t++ = '.';
*t = '\0';
return t - name;
}
/* Make path appear as if a chroot had occurred. This handles a leading
* "/" (either removing it or expanding it) and any leading or embedded
* ".." components that attempt to escape past the module's top dir.
*
* If dest is NULL, a buffer is allocated to hold the result. It is legal
* to call with the dest and the path (p) pointing to the same buffer, but
* rootdir will be ignored to avoid expansion of the string.
*
* The rootdir string contains a value to use in place of a leading slash.
* Specify NULL to get the default of "module_dir".
*
* The depth var is a count of how many '..'s to allow at the start of the
* path.
*
* We also clean the path in a manner similar to clean_fname() but with a
* few differences:
*
* Turns multiple adjacent slashes into a single slash, gets rid of "." dir
* elements (INCLUDING a trailing dot dir), PRESERVES a trailing slash, and
* ALWAYS collapses ".." elements (except for those at the start of the
* string up to "depth" deep). If the resulting name would be empty,
* change it into a ".". */
char *sanitize_path(char *dest, const char *p, const char *rootdir, int depth,
int flags)
{
char *start, *sanp;
int rlen = 0, drop_dot_dirs = !relative_paths || !(flags & SP_KEEP_DOT_DIRS);
if (dest != p) {
int plen = strlen(p);
if (*p == '/') {
if (!rootdir)
rootdir = module_dir;
rlen = strlen(rootdir);
depth = 0;
p++;
}
if (dest) {
if (rlen + plen + 1 >= MAXPATHLEN)
return NULL;
} else if (!(dest = new_array(char, rlen + plen + 1)))
out_of_memory("sanitize_path");
if (rlen) {
memcpy(dest, rootdir, rlen);
if (rlen > 1)
dest[rlen++] = '/';
}
}
if (drop_dot_dirs) {
while (*p == '.' && p[1] == '/')
p += 2;
}
start = sanp = dest + rlen;
/* This loop iterates once per filename component in p, pointing at
* the start of the name (past any prior slash) for each iteration. */
while (*p) {
/* discard leading or extra slashes */
if (*p == '/') {
p++;
continue;
}
if (drop_dot_dirs) {
if (*p == '.' && (p[1] == '/' || p[1] == '\0')) {
/* skip "." component */
p++;
continue;
}
}
if (*p == '.' && p[1] == '.' && (p[2] == '/' || p[2] == '\0')) {
/* ".." component followed by slash or end */
if (depth <= 0 || sanp != start) {
p += 2;
if (sanp != start) {
/* back up sanp one level */
--sanp; /* now pointing at slash */
while (sanp > start && sanp[-1] != '/')
sanp--;
}
continue;
}
/* allow depth levels of .. at the beginning */
depth--;
/* move the virtual beginning to leave the .. alone */
start = sanp + 3;
}
/* copy one component through next slash */
while (*p && (*sanp++ = *p++) != '/') {}
}
if (sanp == dest) {
/* ended up with nothing, so put in "." component */
*sanp++ = '.';
}
*sanp = '\0';
return dest;
}
/* Like chdir(), but it keeps track of the current directory (in the
* global "curr_dir"), and ensures that the path size doesn't overflow.
* Also cleans the path using the clean_fname() function. */
int change_dir(const char *dir, int set_path_only)
{
static int initialised;
unsigned int len;
if (!initialised) {