Subroutine for copying regular files.

1 files changed, 115 insertions, 0 deletions

diff --git a/lib/copy-file.c b/lib/copy-file.c
new file mode 100644
index 0000000..130ef66
--- /dev/null
+++ b/lib/copy-file.c
@@ -0,0 +1,115 @@
+/* Copying of files.
+   Copyright (C) 2001 Free Software Foundation, Inc.
+   Written by Bruno Haible <haible@clisp.cons.org>, 2001.
+
+   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 2, 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, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+/* Specification.  */
+#include "copy-file.h"
+
+#include <errno.h>
+#include <fcntl.h>
+
+#if HAVE_UTIME || HAVE_UTIMES
+# include <utime.h>
+#endif
+
+#include "error.h"
+#include "full-write.h"
+#include "system.h"
+#include "libgettext.h"
+
+#define _(str) gettext (str)
+
+/* On reasonable systems, binary I/O is the default.  */
+#ifndef O_BINARY
+# define O_BINARY 0
+#endif
+
+void
+copy_file (src_filename, dest_filename)
+     const char *src_filename;
+     const char *dest_filename;
+{
+  int src_fd;
+  struct stat statbuf;
+  int mode;
+  int dest_fd;
+  char buf[4096];
+  const int buf_size = sizeof (buf);
+
+  src_fd = open (src_filename, O_RDONLY | O_BINARY);
+  if (src_fd < 0 || fstat (src_fd, &statbuf) < 0)
+    error (EXIT_FAILURE, errno, _("error while opening \"%s\" for reading"),
+	   src_filename);
+
+  mode = statbuf.st_mode & 07777;
+
+  dest_fd = open (dest_filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0600);
+  if (dest_fd < 0)
+    error (EXIT_FAILURE, errno, _("cannot open backup file \"%s\" for writing"),
+	   dest_filename);
+
+  /* Copy the file contents.  */
+  for (;;)
+    {
+      ssize_t n_read = read (src_fd, buf, buf_size);
+      if (n_read < 0)
+	{
+#ifdef EINTR
+	  if (errno == EINTR)
+	    continue;
+#endif
+	  error (EXIT_FAILURE, errno, _("error reading \"%s\""), src_filename);
+	}
+      if (n_read == 0)
+	break;
+
+      if (full_write (dest_fd, buf, n_read) < 0)
+	error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
+    }
+
+  if (close (dest_fd) < 0)
+    error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
+  if (close (src_fd) < 0)
+    error (EXIT_FAILURE, errno, _("error after reading \"%s\""), src_filename);
+
+  /* Preserve the access and modification times.  */
+#if HAVE_UTIME
+  {
+    struct utimbuf ut;
+
+    ut.actime = statbuf.st_atime;
+    ut.modtime = statbuf.st_mtime;
+    utime (dest_filename, &ut);
+  }
+#elif HAVE_UTIMES
+  {
+    struct timeval ut[2];
+
+    ut[0].tv_sec = statbuf.st_atime; ut[0].tv_usec = 0;
+    ut[1].tv_sec = statbuf.st_mtime; ut[1].tv_usec = 0;
+    utimes (dest_filename, &ut);
+  }
+#endif
+
+  /* Preserve the access permissions.  */
+  chmod (dest_filename, mode);
+}