-/* full-write.c -- an interface to write that retries after interrupts
- Copyright (C) 1993, 1994 Free Software Foundation, Inc.
+/* An interface to read and write that retries (if necessary) until complete.
- This program is free software; you can redistribute it and/or modify
+ Copyright (C) 1993-1994, 1997-2006, 2009-2011 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 2, or (at your option)
- any later version.
+ 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
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., 675 Mass Ave, Cambridge, MA 02139, USA.
-
- Copied largely from GNU C's cccp.c.
- */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#ifdef HAVE_CONFIG_H
#include <config.h>
-#endif
-
-#include <sys/types.h>
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
+/* Specification. */
+#ifdef FULL_READ
+# include "full-read.h"
+#else
+# include "full-write.h"
#endif
#include <errno.h>
-#ifndef errno
-extern int errno;
+
+#ifdef FULL_READ
+# include "safe-read.h"
+# define safe_rw safe_read
+# define full_rw full_read
+# undef const
+# define const /* empty */
+#else
+# include "safe-write.h"
+# define safe_rw safe_write
+# define full_rw full_write
#endif
-/* Write LEN bytes at PTR to descriptor DESC, retrying if interrupted.
- Return LEN upon success, write's (negative) error code otherwise. */
+#ifdef FULL_READ
+/* Set errno to zero upon EOF. */
+# define ZERO_BYTE_TRANSFER_ERRNO 0
+#else
+/* Some buggy drivers return 0 when one tries to write beyond
+ a device's end. (Example: Linux 1.2.13 on /dev/fd0.)
+ Set errno to ENOSPC so they get a sensible diagnostic. */
+# define ZERO_BYTE_TRANSFER_ERRNO ENOSPC
+#endif
-int
-full_write (desc, ptr, len)
- int desc;
- char *ptr;
- size_t len;
+/* Write(read) COUNT bytes at BUF to(from) descriptor FD, retrying if
+ interrupted or if a partial write(read) occurs. Return the number
+ of bytes transferred.
+ When writing, set errno if fewer than COUNT bytes are written.
+ When reading, if fewer than COUNT bytes are read, you must examine
+ errno to distinguish failure from EOF (errno == 0). */
+size_t
+full_rw (int fd, const void *buf, size_t count)
{
- int total_written;
+ size_t total = 0;
+ const char *ptr = (const char *) buf;
- total_written = 0;
- while (len > 0)
+ while (count > 0)
{
- int written = write (desc, ptr, len);
- if (written < 0)
- {
-#ifdef EINTR
- if (errno == EINTR)
- continue;
-#endif
- return written;
- }
- total_written += written;
- ptr += written;
- len -= written;
+ size_t n_rw = safe_rw (fd, ptr, count);
+ if (n_rw == (size_t) -1)
+ break;
+ if (n_rw == 0)
+ {
+ errno = ZERO_BYTE_TRANSFER_ERRNO;
+ break;
+ }
+ total += n_rw;
+ ptr += n_rw;
+ count -= n_rw;
}
- return total_written;
+
+ return total;
}