[PATCH 1/4] Sync canonicalize with gnulib [BZ #10635]
Adhemerval Zanella
adhemerval.zanella@linaro.org
Thu Sep 10 15:19:12 GMT 2020
It sync with gnulib version 44358d4d165b with the following exceptions:
- All the logic to which __getcwd use.
- MAXSYMLINKS define (glibc already handles it on eloop-threshold.h).
- The pathmax.h logic to handle //path (neither Linux nor Hurd makes
this distinction).
- Don't explict set ENOMEM on malloc failure (it is already handled
by malloc itself).
- The usage of malloca.h routines.
Checked on x86_64-linux-gnu
---
stdlib/canonicalize.c | 244 +++++++++++++++++++++++-------------------
1 file changed, 131 insertions(+), 113 deletions(-)
diff --git a/stdlib/canonicalize.c b/stdlib/canonicalize.c
index cbd885a3c5..c58439b3fd 100644
--- a/stdlib/canonicalize.c
+++ b/stdlib/canonicalize.c
@@ -16,8 +16,9 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <assert.h>
#include <stdlib.h>
+
+#include <alloca.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
@@ -29,10 +30,10 @@
#include <shlib-compat.h>
/* Return the canonical absolute name of file NAME. A canonical name
- does not contain any `.', `..' components nor any repeated path
+ does not contain any ".", ".." components nor any repeated path
separators ('/') or symlinks. All path components must exist. If
RESOLVED is null, the result is malloc'd; otherwise, if the
- canonical name is PATH_MAX chars or more, returns null with `errno'
+ canonical name is PATH_MAX chars or more, returns null with 'errno'
set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
returns the name in RESOLVED. If the name cannot be resolved and
RESOLVED is non-NULL, it contains the path of the first component
@@ -50,9 +51,9 @@ __realpath (const char *name, char *resolved)
if (name == NULL)
{
/* As per Single Unix Specification V2 we must return an error if
- either parameter is a null pointer. We extend this to allow
- the RESOLVED parameter to be NULL in case the we are expected to
- allocate the room for the return value. */
+ either parameter is a null pointer. We extend this to allow
+ the RESOLVED parameter to be NULL in case the we are expected to
+ allocate the room for the return value. */
__set_errno (EINVAL);
return NULL;
}
@@ -60,7 +61,7 @@ __realpath (const char *name, char *resolved)
if (name[0] == '\0')
{
/* As per Single Unix Specification V2 we must return an error if
- the name argument points to an empty string. */
+ the name argument points to an empty string. */
__set_errno (ENOENT);
return NULL;
}
@@ -70,152 +71,169 @@ __realpath (const char *name, char *resolved)
#else
path_max = __pathconf (name, _PC_PATH_MAX);
if (path_max <= 0)
- path_max = 1024;
+ path_max = 8192;
#endif
if (resolved == NULL)
{
rpath = malloc (path_max);
if (rpath == NULL)
- return NULL;
+ return NULL;
}
else
rpath = resolved;
rpath_limit = rpath + path_max;
+
if (name[0] != '/')
{
if (!__getcwd (rpath, path_max))
- {
- rpath[0] = '\0';
- goto error;
- }
- dest = __rawmemchr (rpath, '\0');
+ {
+ rpath[0] = '\0';
+ goto error;
+ }
+ dest = strchr (rpath, '\0');
}
else
{
- rpath[0] = '/';
- dest = rpath + 1;
+ dest = rpath;
+ *dest++ = '/';
}
+ start = name;
- for (start = end = name; *start; start = end)
+ for (end = start; *start; start = end)
{
+#ifdef _LIBC
struct stat64 st;
- int n;
+#else
+ struct stat st;
+#endif
/* Skip sequence of multiple path-separators. */
while (*start == '/')
- ++start;
+ ++start;
/* Find end of path component. */
for (end = start; *end && *end != '/'; ++end)
- /* Nothing. */;
+ /* Nothing. */;
if (end - start == 0)
- break;
+ break;
else if (end - start == 1 && start[0] == '.')
- /* nothing */;
+ /* nothing */;
else if (end - start == 2 && start[0] == '.' && start[1] == '.')
- {
- /* Back up to previous component, ignore if at root already. */
- if (dest > rpath + 1)
- while ((--dest)[-1] != '/');
- }
+ {
+ /* Back up to previous component, ignore if at root already. */
+ if (dest > rpath + 1)
+ for (--dest; dest > rpath && dest[-1] != '/'; --dest)
+ continue;
+ }
else
- {
- size_t new_size;
-
- if (dest[-1] != '/')
- *dest++ = '/';
-
- if (dest + (end - start) >= rpath_limit)
- {
- ptrdiff_t dest_offset = dest - rpath;
- char *new_rpath;
-
- if (resolved)
- {
- __set_errno (ENAMETOOLONG);
- if (dest > rpath + 1)
- dest--;
- *dest = '\0';
- goto error;
- }
- new_size = rpath_limit - rpath;
- if (end - start + 1 > path_max)
- new_size += end - start + 1;
- else
- new_size += path_max;
- new_rpath = (char *) realloc (rpath, new_size);
- if (new_rpath == NULL)
- goto error;
- rpath = new_rpath;
- rpath_limit = rpath + new_size;
-
- dest = rpath + dest_offset;
- }
-
- dest = __mempcpy (dest, start, end - start);
- *dest = '\0';
-
- if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
- goto error;
-
- if (S_ISLNK (st.st_mode))
- {
- char *buf = __alloca (path_max);
- size_t len;
-
- if (++num_links > __eloop_threshold ())
- {
- __set_errno (ELOOP);
- goto error;
- }
-
- n = __readlink (rpath, buf, path_max - 1);
- if (n < 0)
- goto error;
- buf[n] = '\0';
-
- if (!extra_buf)
- extra_buf = __alloca (path_max);
-
- len = strlen (end);
- if (path_max - n <= len)
- {
- __set_errno (ENAMETOOLONG);
- goto error;
- }
-
- /* 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 = rpath + 1; /* It's an absolute symlink */
- else
- /* Back up to previous component, ignore if at root already: */
- if (dest > rpath + 1)
- while ((--dest)[-1] != '/');
- }
- else if (!S_ISDIR (st.st_mode) && *end != '\0')
- {
- __set_errno (ENOTDIR);
- goto error;
- }
- }
+ {
+ size_t new_size;
+
+ if (dest[-1] != '/')
+ *dest++ = '/';
+
+ if (dest + (end - start) >= rpath_limit)
+ {
+ ptrdiff_t dest_offset = dest - rpath;
+ char *new_rpath;
+
+ if (resolved)
+ {
+ __set_errno (ENAMETOOLONG);
+ if (dest > rpath + 1)
+ dest--;
+ *dest = '\0';
+ goto error;
+ }
+ new_size = rpath_limit - rpath;
+ if (end - start + 1 > path_max)
+ new_size += end - start + 1;
+ else
+ new_size += path_max;
+ new_rpath = (char *) realloc (rpath, new_size);
+ if (new_rpath == NULL)
+ goto error;
+ rpath = new_rpath;
+ rpath_limit = rpath + new_size;
+
+ dest = rpath + dest_offset;
+ }
+
+ dest = __mempcpy (dest, start, end - start);
+ *dest = '\0';
+
+ if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
+ goto error;
+
+ if (S_ISLNK (st.st_mode))
+ {
+ char *buf = __alloca (path_max);
+ size_t len;
+ ssize_t n;
+
+ if (++num_links > __eloop_threshold ())
+ {
+ __set_errno (ELOOP);
+ goto error;
+ }
+
+ n = __readlink (rpath, buf, path_max - 1);
+ if (n < 0)
+ goto error;
+ buf[n] = '\0';
+
+ if (!extra_buf)
+ extra_buf = __alloca (path_max);
+
+ len = strlen (end);
+ /* Check that n + len + 1 doesn't overflow and is <= path_max. */
+ if (n >= SIZE_MAX - len || n + len >= path_max)
+ {
+ __set_errno (ENAMETOOLONG);
+ goto error;
+ }
+
+ /* 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 = rpath;
+ *dest++ = '/'; /* It's an absolute symlink */
+ }
+ else
+ {
+ /* Back up to previous component, ignore if at root
+ already: */
+ if (dest > rpath + 1)
+ for (--dest; dest > rpath && dest[-1] != '/'; --dest)
+ continue;
+ }
+ }
+ else if (!S_ISDIR (st.st_mode) && *end != '\0')
+ {
+ __set_errno (ENOTDIR);
+ goto error;
+ }
+ }
}
if (dest > rpath + 1 && dest[-1] == '/')
--dest;
*dest = '\0';
- assert (resolved == NULL || resolved == rpath);
return rpath;
error:
- assert (resolved == NULL || resolved == rpath);
- if (resolved == NULL)
- free (rpath);
+ {
+ int saved_errno = errno;
+ if (resolved == NULL)
+ free (rpath);
+ __set_errno (saved_errno);
+ }
return NULL;
}
libc_hidden_def (__realpath)
--
2.25.1
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