lib/dprintf.c

   1 /* Formatted output to a file descriptor.
   2    Copyright (C) 2009-2017 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #ifdef HAVE_CONFIG_H
  18 # include <config.h>
  19 #endif
  20
  21 /* Specification.  */
  22 #include <stdio.h>
  23
  24 #include <errno.h>
  25 #include <limits.h>
  26 #include <stdarg.h>
  27 #include <stdlib.h>
  28
  29 #include "full-write.h"
  30 #include "vasnprintf.h"
  31
  32 int
  33 dprintf (int fd, const char *format, ...)
  34 {
  35   char buf[2000];
  36   char *output;
  37   size_t len;
  38   size_t lenbuf = sizeof (buf);
  39   va_list args;
  40
  41   va_start (args, format);
  42   output = vasnprintf (buf, &lenbuf, format, args);
  43   len = lenbuf;
  44   va_end (args);
  45
  46   if (!output)
  47     return -1;
  48
  49   if (full_write (fd, output, len) < len)
  50     {
  51       if (output != buf)
  52         {
  53           int saved_errno = errno;
  54           free (output);
  55           errno = saved_errno;
  56         }
  57       return -1;
  58     }
  59
  60   if (output != buf)
  61     free (output);
  62
  63   if (len > INT_MAX)
  64     {
  65       errno = EOVERFLOW;
  66       return -1;
  67     }
  68
  69   return len;
  70 }