Blame libio/iogetdelim.c

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/* Copyright (C) 1994-2018 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <http://www.gnu.org/licenses/>.
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   As a special exception, if you link the code in this file with
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   files compiled with a GNU compiler to produce an executable,
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   that does not cause the resulting executable to be covered by
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   the GNU Lesser General Public License.  This exception does not
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   however invalidate any other reasons why the executable file
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   might be covered by the GNU Lesser General Public License.
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   This exception applies to code released by its copyright holders
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   in files containing the exception.  */
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#include <stdlib.h>
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#include "libioP.h"
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#include <string.h>
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#include <errno.h>
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#include <limits.h>
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/* Read up to (and including) a TERMINATOR from FP into *LINEPTR
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   (and null-terminate it).  *LINEPTR is a pointer returned from malloc (or
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   NULL), pointing to *N characters of space.  It is realloc'ed as
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   necessary.  Returns the number of characters read (not including the
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   null terminator), or -1 on error or EOF.  */
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ssize_t
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_IO_getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
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{
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  ssize_t result;
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  ssize_t cur_len = 0;
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  ssize_t len;
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  if (lineptr == NULL || n == NULL)
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    {
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      __set_errno (EINVAL);
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      return -1;
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    }
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  CHECK_FILE (fp, -1);
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  _IO_acquire_lock (fp);
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  if (_IO_ferror_unlocked (fp))
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    {
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      result = -1;
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      goto unlock_return;
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    }
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  if (*lineptr == NULL || *n == 0)
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    {
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      *n = 120;
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      *lineptr = (char *) malloc (*n);
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      if (*lineptr == NULL)
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	{
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	  result = -1;
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	  goto unlock_return;
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	}
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    }
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  len = fp->_IO_read_end - fp->_IO_read_ptr;
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  if (len <= 0)
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    {
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      if (__underflow (fp) == EOF)
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	{
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	  result = -1;
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	  goto unlock_return;
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	}
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      len = fp->_IO_read_end - fp->_IO_read_ptr;
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    }
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  for (;;)
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    {
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      size_t needed;
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      char *t;
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      t = (char *) memchr ((void *) fp->_IO_read_ptr, delimiter, len);
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      if (t != NULL)
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	len = (t - fp->_IO_read_ptr) + 1;
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      if (__glibc_unlikely (len >= SSIZE_MAX - cur_len))
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	{
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	  __set_errno (EOVERFLOW);
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	  result = -1;
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	  goto unlock_return;
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	}
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      /* Make enough space for len+1 (for final NUL) bytes.  */
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      needed = cur_len + len + 1;
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      if (needed > *n)
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	{
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	  char *new_lineptr;
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	  if (needed < 2 * *n)
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	    needed = 2 * *n;  /* Be generous. */
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	  new_lineptr = (char *) realloc (*lineptr, needed);
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	  if (new_lineptr == NULL)
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	    {
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	      result = -1;
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	      goto unlock_return;
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	    }
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	  *lineptr = new_lineptr;
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	  *n = needed;
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	}
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      memcpy (*lineptr + cur_len, (void *) fp->_IO_read_ptr, len);
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      fp->_IO_read_ptr += len;
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      cur_len += len;
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      if (t != NULL || __underflow (fp) == EOF)
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	break;
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      len = fp->_IO_read_end - fp->_IO_read_ptr;
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    }
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  (*lineptr)[cur_len] = '\0';
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  result = cur_len;
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unlock_return:
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  _IO_release_lock (fp);
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  return result;
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}
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weak_alias (_IO_getdelim, __getdelim)
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weak_alias (_IO_getdelim, getdelim)