Home | History | Annotate | Download | only in lib 
      1 /* getdelim.c --- Implementation of replacement getdelim function.
      2    Copyright (C) 1994, 1996-1998, 2001, 2003, 2005-2012 Free Software
      3    Foundation, Inc.
      4 
      5    This program is free software; you can redistribute it and/or
      6    modify it under the terms of the GNU General Public License as
      7    published by the Free Software Foundation; either version 3, or (at
      8    your option) any later version.
      9 
     10    This program is distributed in the hope that it will be useful, but
     11    WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13    General Public License for more details.
     14 
     15    You should have received a copy of the GNU General Public License
     16    along with this program; if not, see <http://www.gnu.org/licenses/>.  */
     17 
     18 /* Ported from glibc by Simon Josefsson. */
     19 
     20 #include <config.h>
     21 
     22 /* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
     23    optimizes away the lineptr == NULL || n == NULL || fp == NULL tests below.  */
     24 #define _GL_ARG_NONNULL(params)
     25 
     26 #include <stdio.h>
     27 
     28 #include <limits.h>
     29 #include <stdint.h>
     30 #include <stdlib.h>
     31 #include <errno.h>
     32 
     33 #ifndef SSIZE_MAX
     34 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
     35 #endif
     36 
     37 #if USE_UNLOCKED_IO
     38 # include "unlocked-io.h"
     39 # define getc_maybe_unlocked(fp)        getc(fp)
     40 #elif !HAVE_FLOCKFILE || !HAVE_FUNLOCKFILE || !HAVE_DECL_GETC_UNLOCKED
     41 # undef flockfile
     42 # undef funlockfile
     43 # define flockfile(x) ((void) 0)
     44 # define funlockfile(x) ((void) 0)
     45 # define getc_maybe_unlocked(fp)        getc(fp)
     46 #else
     47 # define getc_maybe_unlocked(fp)        getc_unlocked(fp)
     48 #endif
     49 
     50 /* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
     51    NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
     52    NULL), pointing to *N characters of space.  It is realloc'ed as
     53    necessary.  Returns the number of characters read (not including
     54    the null terminator), or -1 on error or EOF.  */
     55 
     56 ssize_t
     57 getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
     58 {
     59   ssize_t result;
     60   size_t cur_len = 0;
     61 
     62   if (lineptr == NULL || n == NULL || fp == NULL)
     63     {
     64       errno = EINVAL;
     65       return -1;
     66     }
     67 
     68   flockfile (fp);
     69 
     70   if (*lineptr == NULL || *n == 0)
     71     {
     72       char *new_lineptr;
     73       *n = 120;
     74       new_lineptr = (char *) realloc (*lineptr, *n);
     75       if (new_lineptr == NULL)
     76         {
     77           result = -1;
     78           goto unlock_return;
     79         }
     80       *lineptr = new_lineptr;
     81     }
     82 
     83   for (;;)
     84     {
     85       int i;
     86 
     87       i = getc_maybe_unlocked (fp);
     88       if (i == EOF)
     89         {
     90           result = -1;
     91           break;
     92         }
     93 
     94       /* Make enough space for len+1 (for final NUL) bytes.  */
     95       if (cur_len + 1 >= *n)
     96         {
     97           size_t needed_max =
     98             SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
     99           size_t needed = 2 * *n + 1;   /* Be generous. */
    100           char *new_lineptr;
    101 
    102           if (needed_max < needed)
    103             needed = needed_max;
    104           if (cur_len + 1 >= needed)
    105             {
    106               result = -1;
    107               errno = EOVERFLOW;
    108               goto unlock_return;
    109             }
    110 
    111           new_lineptr = (char *) realloc (*lineptr, needed);
    112           if (new_lineptr == NULL)
    113             {
    114               result = -1;
    115               goto unlock_return;
    116             }
    117 
    118           *lineptr = new_lineptr;
    119           *n = needed;
    120         }
    121 
    122       (*lineptr)[cur_len] = i;
    123       cur_len++;
    124 
    125       if (i == delimiter)
    126         break;
    127     }
    128   (*lineptr)[cur_len] = '\0';
    129   result = cur_len ? cur_len : result;
    130 
    131  unlock_return:
    132   funlockfile (fp); /* doesn't set errno */
    133 
    134   return result;
    135 }
    136