box/libbb/full_write.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   8  */
   9
  10 #include "libbb.h"
  11
  12 /*
  13  * Write all of the supplied buffer out to a file.
  14  * This does multiple writes as necessary.
  15  * Returns the amount written, or -1 on an error.
  16  */
  17 ssize_t full_write(int fd, const void *buf, size_t len)
  18 {
  19         ssize_t cc;
  20         ssize_t total;
  21
  22         total = 0;
  23
  24         while (len) {
  25                 cc = safe_write(fd, buf, len);
  26
  27                 if (cc < 0)
  28                         return cc;      /* write() returns -1 on failure. */
  29
  30                 total += cc;
  31                 buf = ((const char *)buf) + cc;
  32                 len -= cc;
  33         }
  34
  35         return total;
  36 }