Update to most recent Gnulib

[pspp-builds.git] / src / data / make-file.c

diff --git a/src/data/make-file.c b/src/data/make-file.c
index 051905b821ad0fbd3ec5a8329c8e817be6550816..f5cda498a89358662965a01c2b5e44a39c5a707b 100644 (file)
--- a/src/data/make-file.c
+++ b/src/data/make-file.c
@@ -16,14 +16,20 @@
 
 #include <config.h>
 #include <assert.h>
+#include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <stdio.h>
-#include "file-name.h"
-#include "make-file.h"
+#include <sys/stat.h>
+
+#include <data/file-name.h>
+#include <data/make-file.h>
+#include <libpspp/ll.h>
 #include <libpspp/message.h>
 
+#include "fatal-signal.h"
+#include "tempname.h"
 #include "xalloc.h"
 
 #include "gettext.h"
@@ -105,7 +111,197 @@ make_unique_file_stream (FILE **fp, char **file_name)
 
   return 1;
 }
+\f
+struct replace_file
+  {
+    struct ll ll;
+    char *file_name;
+    char *tmp_name;
+  };
+
+static struct ll_list all_files = LL_INITIALIZER (all_files);
+
+static void free_replace_file (struct replace_file *);
+static void unlink_replace_files (void);
+
+struct replace_file *
+replace_file_start (const char *file_name, const char *mode,
+                    mode_t permissions, FILE **fp, char **tmp_name)
+{
+  static bool registered;
+  struct stat s;
+  struct replace_file *rf;
+  int fd;
+
+  /* If FILE_NAME represents a special file, write to it directly
+     instead of trying to replace it. */
+  if (stat (file_name, &s) == 0 && !S_ISREG (s.st_mode))
+    {
+      /* Open file descriptor. */
+      fd = open (file_name, O_WRONLY);
+      if (fd < 0)
+        {
+          msg (ME, _("Opening %s for writing: %s."),
+               file_name, strerror (errno));
+          return NULL;
+        }
+
+      /* Open file as stream. */
+      *fp = fdopen (fd, mode);
+      if (*fp == NULL)
+        {
+          msg (ME, _("Opening stream for %s: %s."),
+               file_name, strerror (errno));
+          close (fd);
+          return NULL;
+        }
+
+      rf = xmalloc (sizeof *rf);
+      rf->file_name = NULL;
+      rf->tmp_name = xstrdup (file_name);
+      if (tmp_name != NULL)
+        *tmp_name = rf->tmp_name;
+      return rf;
+    }
+
+  if (!registered)
+    {
+      at_fatal_signal (unlink_replace_files);
+      registered = true;
+    }
+  block_fatal_signals ();
+
+  rf = xmalloc (sizeof *rf);
+  rf->file_name = xstrdup (file_name);
+  for (;;)
+    {
+      /* Generate unique temporary file name. */
+      rf->tmp_name = xasprintf ("%s.tmpXXXXXX", file_name);
+      if (gen_tempname (rf->tmp_name, 0600, GT_NOCREATE) < 0)
+        {
+          msg (ME, _("Creating temporary file to replace %s: %s."),
+               rf->file_name, strerror (errno));
+          goto error;
+        }
+
+      /* Create file by that name. */
+      fd = open (rf->tmp_name, O_WRONLY | O_CREAT | O_EXCL | O_BINARY, permissions);
+      if (fd >= 0)
+        break;
+      if (errno != EEXIST)
+        {
+          msg (ME, _("Creating temporary file %s: %s."),
+               rf->tmp_name, strerror (errno));
+          goto error;
+        }
+      free (rf->tmp_name);
+    }
+
+
+  /* Open file as stream. */
+  *fp = fdopen (fd, mode);
+  if (*fp == NULL)
+    {
+      msg (ME, _("Opening stream for temporary file %s: %s."),
+           rf->tmp_name, strerror (errno));
+      close (fd);
+      unlink (rf->tmp_name);
+      goto error;
+    }
+
+  /* Register file for deletion. */
+  ll_push_head (&all_files, &rf->ll);
+  unblock_fatal_signals ();
+
+  if (tmp_name != NULL)
+    *tmp_name = rf->tmp_name;
+
+  return rf;
+
+error:
+  unblock_fatal_signals ();
+  free_replace_file (rf);
+  *fp = NULL;
+  if (tmp_name != NULL)
+    *tmp_name = NULL;
+  return NULL;
+}
 
+bool
+replace_file_commit (struct replace_file *rf)
+{
+  bool ok = true;
 
+  if (rf->file_name != NULL)
+    {
+      int save_errno;
 
+      block_fatal_signals ();
+      ok = rename (rf->tmp_name, rf->file_name) == 0;
+      save_errno = errno;
+      ll_remove (&rf->ll);
+      unblock_fatal_signals ();
 
+      if (!ok)
+        msg (ME, _("Replacing %s by %s: %s."),
+             rf->tmp_name, rf->file_name, strerror (save_errno));
+    }
+  else
+    {
+      /* Special file: no temporary file to rename. */
+    }
+  free_replace_file (rf);
+
+  return ok;
+}
+
+bool
+replace_file_abort (struct replace_file *rf)
+{
+  bool ok = true;
+
+  if (rf->file_name != NULL)
+    {
+      int save_errno;
+
+      block_fatal_signals ();
+      ok = unlink (rf->tmp_name) == 0;
+      save_errno = errno;
+      ll_remove (&rf->ll);
+      unblock_fatal_signals ();
+
+      if (!ok)
+        msg (ME, _("Removing %s: %s."), rf->tmp_name, strerror (save_errno));
+    }
+  else
+    {
+      /* Special file: no temporary file to unlink. */
+    }
+  free_replace_file (rf);
+
+  return ok;
+}
+
+static void
+free_replace_file (struct replace_file *rf)
+{
+  free (rf->file_name);
+  free (rf->tmp_name);
+  free (rf);
+}
+
+static void
+unlink_replace_files (void)
+{
+  struct replace_file *rf;
+
+  block_fatal_signals ();
+  ll_for_each (rf, struct replace_file, ll, &all_files)
+    {
+      /* We don't free_replace_file(RF) because calling free is unsafe
+         from an asynchronous signal handler. */
+      unlink (rf->tmp_name);
+      fflush (stdout);
+    }
+  unblock_fatal_signals ();
+}