Adding upstream version 8.32.upstream/8.32upstream

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

1 files changed, 394 insertions, 0 deletions

diff --git a/src/pwd.c b/src/pwd.c
new file mode 100644
index 0000000..4507b87
--- /dev/null
+++ b/src/pwd.c
@@ -0,0 +1,394 @@
+/* pwd - print current directory
+   Copyright (C) 1994-2020 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 <getopt.h>
+#include <stdio.h>
+#include <sys/types.h>
+
+#include "system.h"
+#include "die.h"
+#include "error.h"
+#include "quote.h"
+#include "root-dev-ino.h"
+#include "xgetcwd.h"
+
+/* The official name of this program (e.g., no 'g' prefix).  */
+#define PROGRAM_NAME "pwd"
+
+#define AUTHORS proper_name ("Jim Meyering")
+
+struct file_name
+{
+  char *buf;
+  size_t n_alloc;
+  char *start;
+};
+
+static struct option const longopts[] =
+{
+  {"logical", no_argument, NULL, 'L'},
+  {"physical", no_argument, NULL, 'P'},
+  {GETOPT_HELP_OPTION_DECL},
+  {GETOPT_VERSION_OPTION_DECL},
+  {NULL, 0, NULL, 0}
+};
+
+void
+usage (int status)
+{
+  if (status != EXIT_SUCCESS)
+    emit_try_help ();
+  else
+    {
+      printf (_("Usage: %s [OPTION]...\n"), program_name);
+      fputs (_("\
+Print the full filename of the current working directory.\n\
+\n\
+"), stdout);
+      fputs (_("\
+  -L, --logical   use PWD from environment, even if it contains symlinks\n\
+  -P, --physical  avoid all symlinks\n\
+"), stdout);
+      fputs (HELP_OPTION_DESCRIPTION, stdout);
+      fputs (VERSION_OPTION_DESCRIPTION, stdout);
+      fputs (_("\n\
+If no option is specified, -P is assumed.\n\
+"), stdout);
+      printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
+      emit_ancillary_info (PROGRAM_NAME);
+    }
+  exit (status);
+}
+
+static void
+file_name_free (struct file_name *p)
+{
+  free (p->buf);
+  free (p);
+}
+
+static struct file_name *
+file_name_init (void)
+{
+  struct file_name *p = xmalloc (sizeof *p);
+
+  /* Start with a buffer larger than PATH_MAX, but beware of systems
+     on which PATH_MAX is very large -- e.g., INT_MAX.  */
+  p->n_alloc = MIN (2 * PATH_MAX, 32 * 1024);
+
+  p->buf = xmalloc (p->n_alloc);
+  p->start = p->buf + (p->n_alloc - 1);
+  p->start[0] = '\0';
+  return p;
+}
+
+/* Prepend the name S of length S_LEN, to the growing file_name, P.  */
+static void
+file_name_prepend (struct file_name *p, char const *s, size_t s_len)
+{
+  size_t n_free = p->start - p->buf;
+  if (n_free < 1 + s_len)
+    {
+      size_t half = p->n_alloc + 1 + s_len;
+      /* Use xnmalloc+free rather than xnrealloc, since with the latter
+         we'd end up copying the data twice: once via realloc, then again
+         to align it with the end of the new buffer.  With xnmalloc, we
+         copy it only once.  */
+      char *q = xnmalloc (2, half);
+      size_t n_used = p->n_alloc - n_free;
+      p->start = q + 2 * half - n_used;
+      memcpy (p->start, p->buf + n_free, n_used);
+      free (p->buf);
+      p->buf = q;
+      p->n_alloc = 2 * half;
+    }
+
+  p->start -= 1 + s_len;
+  p->start[0] = '/';
+  memcpy (p->start + 1, s, s_len);
+}
+
+/* Return a string (malloc'd) consisting of N '/'-separated ".." components.  */
+static char *
+nth_parent (size_t n)
+{
+  char *buf = xnmalloc (3, n);
+  char *p = buf;
+
+  for (size_t i = 0; i < n; i++)
+    {
+      memcpy (p, "../", 3);
+      p += 3;
+    }
+  p[-1] = '\0';
+  return buf;
+}
+
+/* Determine the basename of the current directory, where DOT_SB is the
+   result of lstat'ing "." and prepend that to the file name in *FILE_NAME.
+   Find the directory entry in '..' that matches the dev/i-node of DOT_SB.
+   Upon success, update *DOT_SB with stat information of '..', chdir to '..',
+   and prepend "/basename" to FILE_NAME.
+   Otherwise, exit with a diagnostic.
+   PARENT_HEIGHT is the number of levels '..' is above the starting directory.
+   The first time this function is called (from the initial directory),
+   PARENT_HEIGHT is 1.  This is solely for diagnostics.
+   Exit nonzero upon error.  */
+
+static void
+find_dir_entry (struct stat *dot_sb, struct file_name *file_name,
+                size_t parent_height)
+{
+  DIR *dirp;
+  int fd;
+  struct stat parent_sb;
+  bool use_lstat;
+  bool found;
+
+  dirp = opendir ("..");
+  if (dirp == NULL)
+    die (EXIT_FAILURE, errno, _("cannot open directory %s"),
+         quote (nth_parent (parent_height)));
+
+  fd = dirfd (dirp);
+  if ((0 <= fd ? fchdir (fd) : chdir ("..")) < 0)
+    die (EXIT_FAILURE, errno, _("failed to chdir to %s"),
+         quote (nth_parent (parent_height)));
+
+  if ((0 <= fd ? fstat (fd, &parent_sb) : stat (".", &parent_sb)) < 0)
+    die (EXIT_FAILURE, errno, _("failed to stat %s"),
+         quote (nth_parent (parent_height)));
+
+  /* If parent and child directory are on different devices, then we
+     can't rely on d_ino for useful i-node numbers; use lstat instead.  */
+  use_lstat = (parent_sb.st_dev != dot_sb->st_dev);
+
+  found = false;
+  while (1)
+    {
+      struct dirent const *dp;
+      struct stat ent_sb;
+      ino_t ino;
+
+      errno = 0;
+      if ((dp = readdir_ignoring_dot_and_dotdot (dirp)) == NULL)
+        {
+          if (errno)
+            {
+              /* Save/restore errno across closedir call.  */
+              int e = errno;
+              closedir (dirp);
+              errno = e;
+
+              /* Arrange to give a diagnostic after exiting this loop.  */
+              dirp = NULL;
+            }
+          break;
+        }
+
+      ino = D_INO (dp);
+
+      if (ino == NOT_AN_INODE_NUMBER || use_lstat)
+        {
+          if (lstat (dp->d_name, &ent_sb) < 0)
+            {
+              /* Skip any entry we can't stat.  */
+              continue;
+            }
+          ino = ent_sb.st_ino;
+        }
+
+      if (ino != dot_sb->st_ino)
+        continue;
+
+      /* If we're not crossing a device boundary, then a simple i-node
+         match is enough.  */
+      if ( ! use_lstat || ent_sb.st_dev == dot_sb->st_dev)
+        {
+          file_name_prepend (file_name, dp->d_name, _D_EXACT_NAMLEN (dp));
+          found = true;
+          break;
+        }
+    }
+
+  if (dirp == NULL || closedir (dirp) != 0)
+    {
+      /* Note that this diagnostic serves for both readdir
+         and closedir failures.  */
+      die (EXIT_FAILURE, errno, _("reading directory %s"),
+           quote (nth_parent (parent_height)));
+    }
+
+  if ( ! found)
+    die (EXIT_FAILURE, 0,
+         _("couldn't find directory entry in %s with matching i-node"),
+         quote (nth_parent (parent_height)));
+
+  *dot_sb = parent_sb;
+}
+
+/* Construct the full, absolute name of the current working
+   directory and store it in *FILE_NAME.
+   The getcwd function performs nearly the same task, but is typically
+   unable to handle names longer than PATH_MAX.  This function has
+   no such limitation.  However, this function *can* fail due to
+   permission problems or a lack of memory, while GNU/Linux's getcwd
+   function works regardless of restricted permissions on parent
+   directories.  Upon failure, give a diagnostic and exit nonzero.
+
+   Note: although this function is similar to getcwd, it has a fundamental
+   difference in that it gives a diagnostic and exits upon failure.
+   I would have liked a function that did not exit, and that could be
+   used as a getcwd replacement.  Unfortunately, considering all of
+   the information the caller would require in order to produce good
+   diagnostics, it doesn't seem worth the added complexity.
+   In any case, any getcwd replacement must *not* exceed the PATH_MAX
+   limitation.  Otherwise, functions like 'chdir' would fail with
+   ENAMETOOLONG.
+
+   FIXME-maybe: if find_dir_entry fails due to permissions, try getcwd,
+   in case the unreadable directory is close enough to the root that
+   getcwd works from there.  */
+
+static void
+robust_getcwd (struct file_name *file_name)
+{
+  size_t height = 1;
+  struct dev_ino dev_ino_buf;
+  struct dev_ino *root_dev_ino = get_root_dev_ino (&dev_ino_buf);
+  struct stat dot_sb;
+
+  if (root_dev_ino == NULL)
+    die (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
+         quoteaf ("/"));
+
+  if (stat (".", &dot_sb) < 0)
+    die (EXIT_FAILURE, errno, _("failed to stat %s"), quoteaf ("."));
+
+  while (1)
+    {
+      /* If we've reached the root, we're done.  */
+      if (SAME_INODE (dot_sb, *root_dev_ino))
+        break;
+
+      find_dir_entry (&dot_sb, file_name, height++);
+    }
+
+  /* See if a leading slash is needed; file_name_prepend adds one.  */
+  if (file_name->start[0] == '\0')
+    file_name_prepend (file_name, "", 0);
+}
+
+
+/* Return PWD from the environment if it is acceptable for 'pwd -L'
+   output, otherwise NULL.  */
+static char *
+logical_getcwd (void)
+{
+  struct stat st1;
+  struct stat st2;
+  char *wd = getenv ("PWD");
+  char *p;
+
+  /* Textual validation first.  */
+  if (!wd || wd[0] != '/')
+    return NULL;
+  p = wd;
+  while ((p = strstr (p, "/.")))
+    {
+      if (!p[2] || p[2] == '/'
+          || (p[2] == '.' && (!p[3] || p[3] == '/')))
+        return NULL;
+      p++;
+    }
+
+  /* System call validation.  */
+  if (stat (wd, &st1) == 0 && stat (".", &st2) == 0 && SAME_INODE (st1, st2))
+    return wd;
+  return NULL;
+}
+
+
+int
+main (int argc, char **argv)
+{
+  char *wd;
+  /* POSIX requires a default of -L, but most scripts expect -P.
+     Currently shells default to -L, while stand-alone
+     pwd implementations default to -P.  */
+  bool logical = (getenv ("POSIXLY_CORRECT") != NULL);
+
+  initialize_main (&argc, &argv);
+  set_program_name (argv[0]);
+  setlocale (LC_ALL, "");
+  bindtextdomain (PACKAGE, LOCALEDIR);
+  textdomain (PACKAGE);
+
+  atexit (close_stdout);
+
+  while (1)
+    {
+      int c = getopt_long (argc, argv, "LP", longopts, NULL);
+      if (c == -1)
+        break;
+      switch (c)
+        {
+        case 'L':
+          logical = true;
+          break;
+        case 'P':
+          logical = false;
+          break;
+
+        case_GETOPT_HELP_CHAR;
+
+        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+        default:
+          usage (EXIT_FAILURE);
+        }
+    }
+
+  if (optind < argc)
+    error (0, 0, _("ignoring non-option arguments"));
+
+  if (logical)
+    {
+      wd = logical_getcwd ();
+      if (wd)
+        {
+          puts (wd);
+          return EXIT_SUCCESS;
+        }
+    }
+
+  wd = xgetcwd ();
+  if (wd != NULL)
+    {
+      puts (wd);
+      free (wd);
+    }
+  else
+    {
+      struct file_name *file_name = file_name_init ();
+      robust_getcwd (file_name);
+      puts (file_name->start);
+      file_name_free (file_name);
+    }
+
+  return EXIT_SUCCESS;
+}