libio/iogetdelim.c

   1 /* Copyright (C) 1994-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.
  17
  18    As a special exception, if you link the code in this file with
  19    files compiled with a GNU compiler to produce an executable,
  20    that does not cause the resulting executable to be covered by
  21    the GNU Lesser General Public License.  This exception does not
  22    however invalidate any other reasons why the executable file
  23    might be covered by the GNU Lesser General Public License.
  24    This exception applies to code released by its copyright holders
  25    in files containing the exception.  */
  26
  27 #include <stdlib.h>
  28 #include "libioP.h"
  29 #include <string.h>
  30 #include <errno.h>
  31 #include <limits.h>
  32
  33 /* Read up to (and including) a TERMINATOR from FP into *LINEPTR
  34    (and null-terminate it).  *LINEPTR is a pointer returned from malloc (or
  35    NULL), pointing to *N characters of space.  It is realloc'ed as
  36    necessary.  Returns the number of characters read (not including the
  37    null terminator), or -1 on error or EOF.  */
  38
  39 _IO_ssize_t
  40 _IO_getdelim (lineptr, n, delimiter, fp)
  41      char **lineptr;
  42      _IO_size_t *n;
  43      int delimiter;
  44      _IO_FILE *fp;
  45 {
  46   _IO_ssize_t result;
  47   _IO_ssize_t cur_len = 0;
  48   _IO_ssize_t len;
  49
  50   if (lineptr == NULL || n == NULL)
  51     {
  52       MAYBE_SET_EINVAL;
  53       return -1;
  54     }
  55   CHECK_FILE (fp, -1);
  56   _IO_acquire_lock (fp);
  57   if (_IO_ferror_unlocked (fp))
  58     {
  59       result = -1;
  60       goto unlock_return;
  61     }
  62
  63   if (*lineptr == NULL || *n == 0)
  64     {
  65       *n = 120;
  66       *lineptr = (char *) malloc (*n);
  67       if (*lineptr == NULL)
  68         {
  69           result = -1;
  70           goto unlock_return;
  71         }
  72     }
  73
  74   len = fp->_IO_read_end - fp->_IO_read_ptr;
  75   if (len <= 0)
  76     {
  77       if (__underflow (fp) == EOF)
  78         {
  79           result = -1;
  80           goto unlock_return;
  81         }
  82       len = fp->_IO_read_end - fp->_IO_read_ptr;
  83     }
  84
  85   for (;;)
  86     {
  87       _IO_size_t needed;
  88       char *t;
  89       t = (char *) memchr ((void *) fp->_IO_read_ptr, delimiter, len);
  90       if (t != NULL)
  91         len = (t - fp->_IO_read_ptr) + 1;
  92       if (__glibc_unlikely (len >= SSIZE_MAX - cur_len))
  93         {
  94           __set_errno (EOVERFLOW);
  95           result = -1;
  96           goto unlock_return;
  97         }
  98       /* Make enough space for len+1 (for final NUL) bytes.  */
  99       needed = cur_len + len + 1;
 100       if (needed > *n)
 101         {
 102           char *new_lineptr;
 103
 104           if (needed < 2 * *n)
 105             needed = 2 * *n;  /* Be generous. */
 106           new_lineptr = (char *) realloc (*lineptr, needed);
 107           if (new_lineptr == NULL)
 108             {
 109               result = -1;
 110               goto unlock_return;
 111             }
 112           *lineptr = new_lineptr;
 113           *n = needed;
 114         }
 115       memcpy (*lineptr + cur_len, (void *) fp->_IO_read_ptr, len);
 116       fp->_IO_read_ptr += len;
 117       cur_len += len;
 118       if (t != NULL || __underflow (fp) == EOF)
 119         break;
 120       len = fp->_IO_read_end - fp->_IO_read_ptr;
 121     }
 122   (*lineptr)[cur_len] = '\0';
 123   result = cur_len;
 124
 125 unlock_return:
 126   _IO_release_lock (fp);
 127   return result;
 128 }
 129
 130 #ifdef weak_alias
 131 weak_alias (_IO_getdelim, __getdelim)
 132 weak_alias (_IO_getdelim, getdelim)
 133 #endif