lib/dzprintf.c

   1 /* Formatted output to a file descriptor.
   2    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation, either version 3 of the
   7    License, or (at your option) any later version.
   8
   9    This file 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 Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser 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 <stdarg.h>
  26 #include <stdlib.h>
  27
  28 #include "full-write.h"
  29 #include "intprops.h"
  30 #include "vasnprintf.h"
  31
  32 off64_t
  33 dzprintf (int fd, const char *format, ...)
  34 {
  35   va_list args;
  36   char buf[2000];
  37   char *output;
  38   size_t len;
  39   size_t lenbuf = sizeof (buf);
  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 (len > TYPE_MAXIMUM (off64_t))
  50     {
  51       /* We could write the (huge) output, but then could not return len, as it
  52          would be negative.  Since we want to use the error code ENOMEM, it is
  53          better to treat this case as if vasnprintf had already encountered an
  54          out-of-memory situation.  */
  55       if (output != buf)
  56         free (output);
  57       errno = ENOMEM;
  58       return -1;
  59     }
  60
  61   if (full_write (fd, output, len) < len)
  62     {
  63       if (output != buf)
  64         free (output);
  65       return -1;
  66     }
  67
  68   if (output != buf)
  69     free (output);
  70
  71   return len;
  72 }