1  /* Copyright (C) 1994-2023 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     <https://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  ssize_t
      40  __getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
      41  {
      42    ssize_t result;
      43    ssize_t cur_len = 0;
      44    ssize_t len;
      45  
      46    CHECK_FILE (fp, -1);
      47    _IO_acquire_lock (fp);
      48    if (_IO_ferror_unlocked (fp))
      49      {
      50        result = -1;
      51        goto unlock_return;
      52      }
      53  
      54    if (lineptr == NULL || n == NULL)
      55      {
      56        __set_errno (EINVAL);
      57        fseterr_unlocked (fp);
      58        result = -1;
      59        goto unlock_return;
      60      }
      61  
      62    if (*lineptr == NULL || *n == 0)
      63      {
      64        *n = 120;
      65        *lineptr = (char *) malloc (*n);
      66        if (*lineptr == NULL)
      67  	{
      68  	  fseterr_unlocked (fp);
      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        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  	  fseterr_unlocked (fp);
      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  	      fseterr_unlocked (fp);
     111  	      result = -1;
     112  	      goto unlock_return;
     113  	    }
     114  	  *lineptr = new_lineptr;
     115  	  *n = needed;
     116  	}
     117        memcpy (*lineptr + cur_len, (void *) fp->_IO_read_ptr, len);
     118        fp->_IO_read_ptr += len;
     119        cur_len += len;
     120        if (t != NULL || __underflow (fp) == EOF)
     121  	break;
     122        len = fp->_IO_read_end - fp->_IO_read_ptr;
     123      }
     124    (*lineptr)[cur_len] = '\0';
     125    result = cur_len;
     126  
     127  unlock_return:
     128    _IO_release_lock (fp);
     129    return result;
     130  }
     131  libc_hidden_def (__getdelim)
     132  weak_alias (__getdelim, getdelim)