Adding upstream version 1.21.3.upstream/1.21.3upstream

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

1 files changed, 489 insertions, 0 deletions

diff --git a/lib/canonicalize.c b/lib/canonicalize.c
new file mode 100644
index 0000000..eaf18c6
--- /dev/null
+++ b/lib/canonicalize.c
@@ -0,0 +1,489 @@
+/* Return the canonical absolute name of a given file.
+   Copyright (C) 1996-2022 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 <fcntl.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <filename.h>
+#include <idx.h>
+#include <intprops.h>
+#include <scratch_buffer.h>
+
+#include "attribute.h"
+#include "file-set.h"
+#include "hash-triple.h"
+#include "xalloc.h"
+
+/* Suppress bogus GCC -Wmaybe-uninitialized warnings.  */
+#if defined GCC_LINT || defined lint
+# define IF_LINT(Code) Code
+#else
+# define IF_LINT(Code) /* empty */
+#endif
+
+#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
+# define DOUBLE_SLASH_IS_DISTINCT_ROOT false
+#endif
+
+#if ISSLASH ('\\')
+# define SLASHES "/\\"
+#else
+# define SLASHES "/"
+#endif
+
+/* Return true if FILE's existence can be shown, false (setting errno)
+   otherwise.  Follow symbolic links.  */
+static bool
+file_accessible (char const *file)
+{
+# if HAVE_FACCESSAT
+  return faccessat (AT_FDCWD, file, F_OK, AT_EACCESS) == 0;
+# else
+  struct stat st;
+  return stat (file, &st) == 0 || errno == EOVERFLOW;
+# endif
+}
+
+/* True if concatenating END as a suffix to a file name means that the
+   code needs to check that the file name is that of a searchable
+   directory, since the canonicalize_filename_mode_stk code won't
+   check this later anyway when it checks an ordinary file name
+   component within END.  END must either be empty, or start with a
+   slash.  */
+
+static bool _GL_ATTRIBUTE_PURE
+suffix_requires_dir_check (char const *end)
+{
+  /* If END does not start with a slash, the suffix is OK.  */
+  while (ISSLASH (*end))
+    {
+      /* Two or more slashes act like a single slash.  */
+      do
+        end++;
+      while (ISSLASH (*end));
+
+      switch (*end++)
+        {
+        default: return false;  /* An ordinary file name component is OK.  */
+        case '\0': return true; /* Trailing "/" is trouble.  */
+        case '.': break;        /* Possibly "." or "..".  */
+        }
+      /* Trailing "/.", or "/.." even if not trailing, is trouble.  */
+      if (!*end || (*end == '.' && (!end[1] || ISSLASH (end[1]))))
+        return true;
+    }
+
+  return false;
+}
+
+/* Append this to a file name to test whether it is a searchable directory.
+   On POSIX platforms "/" suffices, but "/./" is sometimes needed on
+   macOS 10.13 <https://bugs.gnu.org/30350>, and should also work on
+   platforms like AIX 7.2 that need at least "/.".  */
+
+#ifdef LSTAT_FOLLOWS_SLASHED_SYMLINK
+static char const dir_suffix[] = "/";
+#else
+static char const dir_suffix[] = "/./";
+#endif
+
+/* Return true if DIR is a searchable dir, false (setting errno) otherwise.
+   DIREND points to the NUL byte at the end of the DIR string.
+   Store garbage into DIREND[0 .. strlen (dir_suffix)].  */
+
+static bool
+dir_check (char *dir, char *dirend)
+{
+  strcpy (dirend, dir_suffix);
+  return file_accessible (dir);
+}
+
+#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 */
+
+static bool
+multiple_bits_set (canonicalize_mode_t i)
+{
+  return (i & (i - 1)) != 0;
+}
+
+/* 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)
+    {
+      idx_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;
+}
+
+
+/* Act like canonicalize_filename_mode (see below), with an additional argument
+   rname_buf that can be used as temporary storage.
+
+   If GCC_LINT is defined, do not inline this function with GCC 10.1
+   and later, to avoid creating a pointer to the stack that GCC
+   -Wreturn-local-addr incorrectly complains about.  See:
+   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93644
+   Although the noinline attribute can hurt performance a bit, no better way
+   to pacify GCC is known; even an explicit #pragma does not pacify GCC.
+   When the GCC bug is fixed this workaround should be limited to the
+   broken GCC versions.  */
+#if _GL_GNUC_PREREQ (10, 1)
+# if defined GCC_LINT || defined lint
+__attribute__ ((__noinline__))
+# elif __OPTIMIZE__ && !__NO_INLINE__
+#  define GCC_BOGUS_WRETURN_LOCAL_ADDR
+# endif
+#endif
+static char *
+canonicalize_filename_mode_stk (const char *name, canonicalize_mode_t can_mode,
+                                struct scratch_buffer *rname_buf)
+{
+  char *dest;
+  char const *start;
+  char const *end;
+  Hash_table *ht = NULL;
+  bool logical = (can_mode & CAN_NOLINKS) != 0;
+  int num_links = 0;
+
+  canonicalize_mode_t can_exist = can_mode & CAN_MODE_MASK;
+  if (multiple_bits_set (can_exist))
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  if (name == NULL)
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  if (name[0] == '\0')
+    {
+      errno = ENOENT;
+      return NULL;
+    }
+
+  struct scratch_buffer extra_buffer, link_buffer;
+  scratch_buffer_init (&extra_buffer);
+  scratch_buffer_init (&link_buffer);
+  scratch_buffer_init (rname_buf);
+  char *rname_on_stack = rname_buf->data;
+  char *rname = rname_on_stack;
+  bool end_in_extra_buffer = false;
+  bool failed = true;
+
+  /* This is always zero for Posix hosts, but can be 2 for MS-Windows
+     and MS-DOS X:/foo/bar file names.  */
+  idx_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name);
+
+  if (!IS_ABSOLUTE_FILE_NAME (name))
+    {
+      while (!getcwd (rname, rname_buf->length))
+        {
+          switch (errno)
+            {
+            case ERANGE:
+              if (scratch_buffer_grow (rname_buf))
+                break;
+              FALLTHROUGH;
+            case ENOMEM:
+              xalloc_die ();
+
+            default:
+              dest = rname;
+              goto error;
+            }
+          rname = rname_buf->data;
+        }
+      dest = rawmemchr (rname, '\0');
+      start = name;
+      prefix_len = FILE_SYSTEM_PREFIX_LEN (rname);
+    }
+  else
+    {
+      dest = mempcpy (rname, name, prefix_len);
+      *dest++ = '/';
+      if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
+        {
+          if (prefix_len == 0 /* implies ISSLASH (name[0]) */
+              && ISSLASH (name[1]) && !ISSLASH (name[2]))
+            {
+              *dest++ = '/';
+#if defined _WIN32 && !defined __CYGWIN__
+              /* For UNC file names '\\server\path\to\file', extend the prefix
+                 to include the server: '\\server\'.  */
+              {
+                idx_t i;
+                for (i = 2; name[i] != '\0' && !ISSLASH (name[i]); )
+                  i++;
+                if (name[i] != '\0' /* implies ISSLASH (name[i]) */
+                    && i + 1 < rname_buf->length)
+                  {
+                    prefix_len = i;
+                    memcpy (dest, name + 2, i - 2 + 1);
+                    dest += i - 2 + 1;
+                  }
+                else
+                  {
+                    /* Either name = '\\server'; this is an invalid file name.
+                       Or name = '\\server\...' and server is more than
+                       rname_buf->length - 4 bytes long.  In either
+                       case, stop the UNC processing.  */
+                  }
+              }
+#endif
+            }
+          *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.  */;
+
+      /* Length of this file name component; it can be zero if a file
+         name ends in '/'.  */
+      idx_t startlen = end - start;
+
+      if (startlen == 0)
+        break;
+      else if (startlen == 1 && start[0] == '.')
+        /* nothing */;
+      else if (startlen == 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
+        {
+          if (!ISSLASH (dest[-1]))
+            *dest++ = '/';
+
+          while (rname + rname_buf->length - dest
+                 < startlen + sizeof dir_suffix)
+            {
+              idx_t dest_offset = dest - rname;
+              if (!scratch_buffer_grow_preserve (rname_buf))
+                xalloc_die ();
+              rname = rname_buf->data;
+              dest = rname + dest_offset;
+            }
+
+          dest = mempcpy (dest, start, startlen);
+          *dest = '\0';
+
+          char *buf;
+          ssize_t n = -1;
+          if (!logical)
+            {
+              while (true)
+                {
+                  buf = link_buffer.data;
+                  idx_t bufsize = link_buffer.length;
+                  n = readlink (rname, buf, bufsize - 1);
+                  if (n < bufsize - 1)
+                    break;
+                  if (!scratch_buffer_grow (&link_buffer))
+                    xalloc_die ();
+                }
+            }
+          if (0 <= n)
+            {
+              /* A physical traversal and RNAME is a symbolic link.  */
+
+              if (num_links < 20)
+                num_links++;
+              else if (*start)
+                {
+                  /* Enough symlinks have been seen that it is time to
+                     worry about being in a symlink cycle.
+                     Get the device and inode of the parent directory, as
+                     pre-2017 POSIX says this info is not reliable for
+                     symlinks.  */
+                  struct stat st;
+                  dest[- startlen] = '\0';
+                  if (stat (*rname ? rname : ".", &st) != 0)
+                    goto error;
+                  dest[- startlen] = *start;
+
+                  /* Detect loops.  We cannot use the cycle-check module here,
+                     since it's possible to encounter the same parent
+                     directory more than once in a given traversal.  However,
+                     encountering the same (parentdir, START) pair twice does
+                     indicate a loop.  */
+                  if (seen_triple (&ht, start, &st))
+                    {
+                      if (can_exist == CAN_MISSING)
+                        continue;
+                      errno = ELOOP;
+                      goto error;
+                    }
+                }
+
+              buf[n] = '\0';
+
+              char *extra_buf = extra_buffer.data;
+              idx_t end_idx IF_LINT (= 0);
+              if (end_in_extra_buffer)
+                end_idx = end - extra_buf;
+              size_t len = strlen (end);
+              if (INT_ADD_OVERFLOW (len, n))
+                xalloc_die ();
+              while (extra_buffer.length <= len + n)
+                {
+                  if (!scratch_buffer_grow_preserve (&extra_buffer))
+                    xalloc_die ();
+                  extra_buf = extra_buffer.data;
+                }
+              if (end_in_extra_buffer)
+                end = extra_buf + end_idx;
+
+              /* Careful here, end may be a pointer into extra_buf... */
+              memmove (&extra_buf[n], end, len + 1);
+              name = end = memcpy (extra_buf, buf, n);
+              end_in_extra_buffer = true;
+
+              if (IS_ABSOLUTE_FILE_NAME (buf))
+                {
+                  idx_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf);
+
+                  dest = mempcpy (rname, buf, 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++;
+                }
+            }
+          else if (! (can_exist == CAN_MISSING
+                      || (suffix_requires_dir_check (end)
+                          ? dir_check (rname, dest)
+                          : !logical
+                          ? errno == EINVAL
+                          : *end || file_accessible (rname))
+                      || (can_exist == CAN_ALL_BUT_LAST
+                          && errno == ENOENT
+                          && !end[strspn (end, SLASHES)])))
+            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++;
+  failed = false;
+
+error:
+  if (ht)
+    hash_free (ht);
+  scratch_buffer_free (&extra_buffer);
+  scratch_buffer_free (&link_buffer);
+
+  if (failed)
+    {
+      scratch_buffer_free (rname_buf);
+      return NULL;
+    }
+
+  *dest++ = '\0';
+  char *result = scratch_buffer_dupfree (rname_buf, dest - rname);
+  if (!result)
+    xalloc_die ();
+  return result;
+}
+
+/* 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)
+{
+  #ifdef GCC_BOGUS_WRETURN_LOCAL_ADDR
+   #warning "GCC might issue a bogus -Wreturn-local-addr warning here."
+   #warning "See <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93644>."
+  #endif
+  struct scratch_buffer rname_buffer;
+  return canonicalize_filename_mode_stk (name, can_mode, &rname_buffer);
+}