libio/iogetdelim.c

   1 /* Copyright (C) 1994,1996-1998,2001,2003,2005,2012
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 #include <stdlib.h>
  29 #include "libioP.h"
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <limits.h>
  33
  34 /* Read up to (and including) a TERMINATOR from FP into *LINEPTR
  35    (and null-terminate it).  *LINEPTR is a pointer returned from malloc (or
  36    NULL), pointing to *N characters of space.  It is realloc'ed as
  37    necessary.  Returns the number of characters read (not including the
  38    null terminator), or -1 on error or EOF.  */
  39
  40 _IO_ssize_t
  41 _IO_getdelim (lineptr, n, delimiter, fp)
  42      char **lineptr;
  43      _IO_size_t *n;
  44      int delimiter;
  45      _IO_FILE *fp;
  46 {
  47   _IO_ssize_t result;
  48   _IO_ssize_t cur_len = 0;
  49   _IO_ssize_t len;
  50
  51   if (lineptr == NULL || n == NULL)
  52     {
  53       MAYBE_SET_EINVAL;
  54       return -1;
  55     }
  56   CHECK_FILE (fp, -1);
  57   _IO_acquire_lock (fp);
  58   if (_IO_ferror_unlocked (fp))
  59     {
  60       result = -1;
  61       goto unlock_return;
  62     }
  63
  64   if (*lineptr == NULL || *n == 0)
  65     {
  66       *n = 120;
  67       *lineptr = (char *) malloc (*n);
  68       if (*lineptr == NULL)
  69         {
  70           result = -1;
  71           goto unlock_return;
  72         }
  73     }
  74
  75   len = fp->_IO_read_end - fp->_IO_read_ptr;
  76   if (len <= 0)
  77     {
  78       if (__underflow (fp) == EOF)
  79         {
  80           result = -1;
  81           goto unlock_return;
  82         }
  83       len = fp->_IO_read_end - fp->_IO_read_ptr;
  84     }
  85
  86   for (;;)
  87     {
  88       _IO_size_t needed;
  89       char *t;
  90       t = (char *) memchr ((void *) fp->_IO_read_ptr, delimiter, len);
  91       if (t != NULL)
  92         len = (t - fp->_IO_read_ptr) + 1;
  93       if (__builtin_expect (len >= SSIZE_MAX - cur_len, 0))
  94         {
  95           __set_errno (EOVERFLOW);
  96           result = -1;
  97           goto unlock_return;
  98         }
  99       /* Make enough space for len+1 (for final NUL) bytes.  */
 100       needed = cur_len + len + 1;
 101       if (needed > *n)
 102         {
 103           char *new_lineptr;
 104
 105           if (needed < 2 * *n)
 106             needed = 2 * *n;  /* Be generous. */
 107           new_lineptr = (char *) realloc (*lineptr, needed);
 108           if (new_lineptr == NULL)
 109             {
 110               result = -1;
 111               goto unlock_return;
 112             }
 113           *lineptr = new_lineptr;
 114           *n = needed;
 115         }
 116       memcpy (*lineptr + cur_len, (void *) fp->_IO_read_ptr, len);
 117       fp->_IO_read_ptr += len;
 118       cur_len += len;
 119       if (t != NULL || __underflow (fp) == EOF)
 120         break;
 121       len = fp->_IO_read_end - fp->_IO_read_ptr;
 122     }
 123   (*lineptr)[cur_len] = '\0';
 124   result = cur_len;
 125
 126 unlock_return:
 127   _IO_release_lock (fp);
 128   return result;
 129 }
 130
 131 #ifdef weak_alias
 132 weak_alias (_IO_getdelim, __getdelim)
 133 weak_alias (_IO_getdelim, getdelim)
 134 #endif