Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 177 insertions, 0 deletions

diff --git a/REORG.TODO/elf/chroot_canon.c b/REORG.TODO/elf/chroot_canon.c
new file mode 100644
index 0000000000..78cd6f4a5e
--- /dev/null
+++ b/REORG.TODO/elf/chroot_canon.c
@@ -0,0 +1,177 @@
+/* Return the canonical absolute name of a given file inside chroot.
+   Copyright (C) 1996-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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; version 2 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 <http://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include <eloop-threshold.h>
+#include <ldconfig.h>
+
+#ifndef PATH_MAX
+#define PATH_MAX 1024
+#endif
+
+/* Return the canonical absolute name of file NAME as if chroot(CHROOT) was
+   done first.  A canonical name does not contain any `.', `..' components
+   nor any repeated path separators ('/') or symlinks.  All path components
+   must exist and NAME must be absolute filename.  The result is malloc'd.
+   The returned name includes the CHROOT prefix.  */
+
+char *
+chroot_canon (const char *chroot, const char *name)
+{
+  char *rpath;
+  char *dest;
+  char *extra_buf = NULL;
+  char *rpath_root;
+  const char *start;
+  const char *end;
+  const char *rpath_limit;
+  int num_links = 0;
+  size_t chroot_len = strlen (chroot);
+
+  if (chroot_len < 1)
+    {
+      __set_errno (EINVAL);
+      return NULL;
+    }
+
+  rpath = xmalloc (chroot_len + PATH_MAX);
+
+  rpath_limit = rpath + chroot_len + PATH_MAX;
+
+  rpath_root = (char *) mempcpy (rpath, chroot, chroot_len) - 1;
+  if (*rpath_root != '/')
+    *++rpath_root = '/';
+  dest = rpath_root + 1;
+
+  for (start = end = name; *start; start = end)
+    {
+      struct stat64 st;
+
+      /* Skip sequence of multiple path-separators.  */
+      while (*start == '/')
+	++start;
+
+      /* Find end of path 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 > rpath_root + 1)
+	    while ((--dest)[-1] != '/');
+	}
+      else
+	{
+	  size_t new_size;
+
+	  if (dest[-1] != '/')
+	    *dest++ = '/';
+
+	  if (dest + (end - start) >= rpath_limit)
+	    {
+	      ptrdiff_t dest_offset = dest - rpath;
+	      char *new_rpath;
+
+	      new_size = rpath_limit - rpath;
+	      if (end - start + 1 > PATH_MAX)
+		new_size += end - start + 1;
+	      else
+		new_size += PATH_MAX;
+	      new_rpath = (char *) xrealloc (rpath, new_size);
+	      rpath = new_rpath;
+	      rpath_limit = rpath + new_size;
+
+	      dest = rpath + dest_offset;
+	    }
+
+	  dest = mempcpy (dest, start, end - start);
+	  *dest = '\0';
+
+	  if (lstat64 (rpath, &st) < 0)
+	    {
+	      if (*end == '\0')
+		goto done;
+	      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;
+		}
+
+	      ssize_t n = readlink (rpath, buf, PATH_MAX - 1);
+	      if (n < 0)
+		{
+		  if (*end == '\0')
+		    goto done;
+		  goto error;
+		}
+	      buf[n] = '\0';
+
+	      if (!extra_buf)
+		extra_buf = alloca (PATH_MAX);
+
+	      len = strlen (end);
+	      if (len >= PATH_MAX - n)
+		{
+		  __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_root + 1;	/* It's an absolute symlink */
+	      else
+		/* Back up to previous component, ignore if at root already: */
+		if (dest > rpath_root + 1)
+		  while ((--dest)[-1] != '/');
+	    }
+	}
+    }
+ done:
+  if (dest > rpath_root + 1 && dest[-1] == '/')
+    --dest;
+  *dest = '\0';
+
+  return rpath;
+
+ error:
+  free (rpath);
+  return NULL;
+}