/* Set up the cycle-detection machinery: */
static bool
setup_dir(FTS *fts)
{
if (fts->fts_options & (FTS_TIGHT_CYCLE_CHECK | FTS_LOGICAL)) {
enum { HT_INITIAL_SIZE = 31 };
fts->fts_cycle.ht = hash_initialize((size_t)HT_INITIAL_SIZE, NULL,
AD_hash, AD_compare, free);
if (! fts->fts_cycle.ht) {
return false;
}
} else {
fts->fts_cycle.state = (struct cycle_check_state *)malloc(sizeof *fts->fts_cycle.state);
if (! fts->fts_cycle.state) {
return false;
}
cycle_check_init(fts->fts_cycle.state);
}
return true;
}
char *
canonicalize_filename_mode (const char *name, canonicalize_mode_t can_mode)
{
char *rname, *dest, *extra_buf = NULL;
char const *start;
char const *end;
char const *rname_limit;
size_t extra_len = 0;
struct cycle_check_state cycle_state;
if (name == NULL)
{
__set_errno (EINVAL);
return NULL;
}
if (name[0] == '\0')
{
__set_errno (ENOENT);
return NULL;
}
if (name[0] != '/')
{
rname = xgetcwd ();
if (!rname)
return NULL;
dest = strchr (rname, '\0');
if (dest - rname < PATH_MAX)
{
char *p = xrealloc (rname, PATH_MAX);
dest = p + (dest - rname);
rname = p;
rname_limit = rname + PATH_MAX;
}
else
{
rname_limit = dest;
}
}
else
{
rname = xmalloc (PATH_MAX);
rname_limit = rname + PATH_MAX;
rname[0] = '/';
dest = rname + 1;
}
cycle_check_init (&cycle_state);
for (start = end = name; *start; start = end)
{
/* Skip sequence of multiple file name separators. */
while (*start == '/')
++start;
/* Find end of component. */
for (end = start; *end && *end != '/'; ++end)
/* Nothing. */;
if (end - start == 0)
break;
else if (end - start == 1 && start[0] == '.')
/* nothing */;
else if (end - start == 2 && start[0] == '.' && start[1] == '.')
{
/* Back up to previous component, ignore if at root already. */
if (dest > rname + 1)
while ((--dest)[-1] != '/');
}
else
{
struct stat st;
if (dest[-1] != '/')
*dest++ = '/';
if (dest + (end - start) >= rname_limit)
{
ptrdiff_t dest_offset = dest - rname;
size_t new_size = rname_limit - rname;
if (end - start + 1 > PATH_MAX)
new_size += end - start + 1;
else
new_size += PATH_MAX;
rname = xrealloc (rname, new_size);
rname_limit = rname + new_size;
dest = rname + dest_offset;
}
dest = memcpy (dest, start, end - start);
dest += end - start;
*dest = '\0';
if (lstat (rname, &st) != 0)
{
if (can_mode == CAN_EXISTING)
goto error;
if (can_mode == CAN_ALL_BUT_LAST && *end)
goto error;
st.st_mode = 0;
}
if (S_ISLNK (st.st_mode))
{
char *buf;
size_t n, len;
if (cycle_check (&cycle_state, &st))
{
__set_errno (ELOOP);
if (can_mode == CAN_MISSING)
continue;
else
goto error;
}
buf = xreadlink (rname, st.st_size);
if (!buf)
{
if (can_mode == CAN_MISSING)
continue;
else
goto error;
}
n = strlen (buf);
len = strlen (end);
if (!extra_len)
{
extra_len =
((n + len + 1) > PATH_MAX) ? (n + len + 1) : PATH_MAX;
extra_buf = xmalloc (extra_len);
}
else if ((n + len + 1) > extra_len)
{
extra_len = n + len + 1;
extra_buf = xrealloc (extra_buf, extra_len);
}
/* Careful here, end may be a pointer into extra_buf... */
memmove (&extra_buf[n], end, len + 1);
name = end = memcpy (extra_buf, buf, n);
if (buf[0] == '/')
dest = rname + 1; /* It's an absolute symlink */
else
/* Back up to previous component, ignore if at root already: */
if (dest > rname + 1)
while ((--dest)[-1] != '/');
free (buf);
}
else
{
if (!S_ISDIR (st.st_mode) && *end && (can_mode != CAN_MISSING))
{
errno = ENOTDIR;
goto error;
}
}
}
}
if (dest > rname + 1 && dest[-1] == '/')
--dest;
*dest = '\0';
free (extra_buf);
return rname;
error:
free (extra_buf);
free (rname);
return NULL;
}