Adding upstream version 8.32.upstream/8.32upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 355 insertions, 0 deletions

diff --git a/lib/canonicalize.c b/lib/canonicalize.c
new file mode 100644
index 0000000..67fc76e
--- /dev/null
+++ b/lib/canonicalize.c
@@ -0,0 +1,355 @@
+/* Return the canonical absolute name of a given file.
+   Copyright (C) 1996-2020 Free Software Foundation, Inc.
+
+   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, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include "canonicalize.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "areadlink.h"
+#include "file-set.h"
+#include "hash-triple.h"
+#include "pathmax.h"
+#include "xalloc.h"
+#include "xgetcwd.h"
+#include "dosname.h"
+
+#define MULTIPLE_BITS_SET(i) (((i) & ((i) - 1)) != 0)
+
+/* In this file, we cannot handle file names longer than PATH_MAX.
+   On systems with no file name length limit, use a fallback.  */
+#ifndef PATH_MAX
+# define PATH_MAX 8192
+#endif
+
+#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
+# define DOUBLE_SLASH_IS_DISTINCT_ROOT 0
+#endif
+
+#if ISSLASH ('\\')
+# define SLASHES "/\\"
+#else
+# define SLASHES "/"
+#endif
+
+#if !((HAVE_CANONICALIZE_FILE_NAME && FUNC_REALPATH_WORKS)      \
+      || GNULIB_CANONICALIZE_LGPL)
+/* Return the canonical absolute name of file NAME.  A canonical name
+   does not contain any ".", ".." components nor any repeated file name
+   separators ('/') or symlinks.  All components must exist.
+   The result is malloc'd.  */
+
+char *
+canonicalize_file_name (const char *name)
+{
+  return canonicalize_filename_mode (name, CAN_EXISTING);
+}
+#endif /* !HAVE_CANONICALIZE_FILE_NAME */
+
+/* Return true if we've already seen the triple, <FILENAME, dev, ino>.
+   If *HT is not initialized, initialize it.  */
+static bool
+seen_triple (Hash_table **ht, char const *filename, struct stat const *st)
+{
+  if (*ht == NULL)
+    {
+      size_t initial_capacity = 7;
+      *ht = hash_initialize (initial_capacity,
+                            NULL,
+                            triple_hash,
+                            triple_compare_ino_str,
+                            triple_free);
+      if (*ht == NULL)
+        xalloc_die ();
+    }
+
+  if (seen_file (*ht, filename, st))
+    return true;
+
+  record_file (*ht, filename, st);
+  return false;
+}
+
+/* Return the canonical absolute name of file NAME, while treating
+   missing elements according to CAN_MODE.  A canonical name
+   does not contain any ".", ".." components nor any repeated file name
+   separators ('/') or, depending on other CAN_MODE flags, symlinks.
+   Whether components must exist or not depends on canonicalize mode.
+   The result is malloc'd.  */
+
+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;
+  Hash_table *ht = NULL;
+  int saved_errno;
+  int can_flags = can_mode & ~CAN_MODE_MASK;
+  bool logical = can_flags & CAN_NOLINKS;
+  size_t prefix_len;
+
+  can_mode &= CAN_MODE_MASK;
+
+  if (MULTIPLE_BITS_SET (can_mode))
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  if (name == NULL)
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  if (name[0] == '\0')
+    {
+      errno = ENOENT;
+      return NULL;
+    }
+
+  /* This is always zero for Posix hosts, but can be 2 for MS-Windows
+     and MS-DOS X:/foo/bar file names.  */
+  prefix_len = FILE_SYSTEM_PREFIX_LEN (name);
+
+  if (!IS_ABSOLUTE_FILE_NAME (name))
+    {
+      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;
+        }
+      start = name;
+      prefix_len = FILE_SYSTEM_PREFIX_LEN (rname);
+    }
+  else
+    {
+      rname = xmalloc (PATH_MAX);
+      rname_limit = rname + PATH_MAX;
+      dest = rname;
+      if (prefix_len)
+        {
+          memcpy (rname, name, prefix_len);
+          dest += prefix_len;
+        }
+      *dest++ = '/';
+      if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
+        {
+          if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len)
+            *dest++ = '/';
+          *dest = '\0';
+        }
+      start = name + prefix_len;
+    }
+
+  for ( ; *start; start = end)
+    {
+      /* Skip sequence of multiple file name separators.  */
+      while (ISSLASH (*start))
+        ++start;
+
+      /* Find end of component.  */
+      for (end = start; *end && !ISSLASH (*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 + prefix_len + 1)
+            for (--dest; dest > rname && !ISSLASH (dest[-1]); --dest)
+              continue;
+          if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1
+              && !prefix_len && ISSLASH (*dest) && !ISSLASH (dest[1]))
+            dest++;
+        }
+      else
+        {
+          struct stat st;
+
+          if (!ISSLASH (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 (logical && (can_mode == CAN_MISSING))
+            {
+              /* Avoid the stat in this case as it's inconsequential.
+                 i.e. we're neither resolving symlinks or testing
+                 component existence.  */
+              st.st_mode = 0;
+            }
+          else if ((logical ? stat (rname, &st) : lstat (rname, &st)) != 0)
+            {
+              /* FIXME: If errno == EOVERFLOW here, the entry exists.  */
+              saved_errno = errno;
+              if (can_mode == CAN_EXISTING)
+                goto error;
+              if (can_mode == CAN_ALL_BUT_LAST)
+                {
+                  if (end[strspn (end, SLASHES)] || saved_errno != ENOENT)
+                    goto error;
+                  continue;
+                }
+              st.st_mode = 0;
+            }
+
+          if (S_ISLNK (st.st_mode))
+            {
+              char *buf;
+              size_t n, len;
+
+              /* Detect loops.  We cannot use the cycle-check module here,
+                 since it's actually possible to encounter the same symlink
+                 more than once in a given traversal.  However, encountering
+                 the same symlink,NAME pair twice does indicate a loop.  */
+              if (seen_triple (&ht, name, &st))
+                {
+                  if (can_mode == CAN_MISSING)
+                    continue;
+                  saved_errno = ELOOP;
+                  goto error;
+                }
+
+              buf = areadlink_with_size (rname, st.st_size);
+              if (!buf)
+                {
+                  if (can_mode == CAN_MISSING && errno != ENOMEM)
+                    continue;
+                  saved_errno = errno;
+                  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 (IS_ABSOLUTE_FILE_NAME (buf))
+                {
+                  size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf);
+
+                  if (pfxlen)
+                    memcpy (rname, buf, pfxlen);
+                  dest = rname + pfxlen;
+                  *dest++ = '/'; /* It's an absolute symlink */
+                  if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
+                    {
+                      if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen)
+                        *dest++ = '/';
+                      *dest = '\0';
+                    }
+                  /* Install the new prefix to be in effect hereafter.  */
+                  prefix_len = pfxlen;
+                }
+              else
+                {
+                  /* Back up to previous component, ignore if at root
+                     already: */
+                  if (dest > rname + prefix_len + 1)
+                    for (--dest; dest > rname && !ISSLASH (dest[-1]); --dest)
+                      continue;
+                  if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1
+                      && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len)
+                    dest++;
+                }
+
+              free (buf);
+            }
+          else
+            {
+              if (!S_ISDIR (st.st_mode) && *end && (can_mode != CAN_MISSING))
+                {
+                  saved_errno = ENOTDIR;
+                  goto error;
+                }
+            }
+        }
+    }
+  if (dest > rname + prefix_len + 1 && ISSLASH (dest[-1]))
+    --dest;
+  if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1 && !prefix_len
+      && ISSLASH (*dest) && !ISSLASH (dest[1]))
+    dest++;
+  *dest = '\0';
+  if (rname_limit != dest + 1)
+    rname = xrealloc (rname, dest - rname + 1);
+
+  free (extra_buf);
+  if (ht)
+    hash_free (ht);
+  return rname;
+
+error:
+  free (extra_buf);
+  free (rname);
+  if (ht)
+    hash_free (ht);
+  errno = saved_errno;
+  return NULL;
+}