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128 lines
3.9 KiB
C
128 lines
3.9 KiB
C
/* xreadline.c - fgets replacement function
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* Copyright (C) 1999, 2004 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of either
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*
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* - the GNU Lesser General Public License as published by the Free
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* Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* or
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*
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* - the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* or both in parallel, as here.
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*
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* This file 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "util.h"
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/* Same as fgets() but if the provided buffer is too short a larger
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one will be allocated. This is similar to getline. A line is
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considered a byte stream ending in a LF.
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If MAX_LENGTH is not NULL, it shall point to a value with the
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maximum allowed allocation.
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Returns the length of the line. EOF is indicated by a line of
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length zero. A truncated line is indicated by setting the value at
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MAX_LENGTH to 0. If the returned value is less then 0 not enough
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memory was enable and ERRNO is set accordingly.
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If a line has been truncated, the file pointer is moved forward to
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the end of the line so that the next read starts with the next
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line. Note that MAX_LENGTH must be re-initialzied in this case.
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Note: The returned buffer is allocated with enough extra space to
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append a CR,LF,Nul
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*/
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ssize_t
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read_line (FILE *fp,
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char **addr_of_buffer, size_t *length_of_buffer,
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size_t *max_length)
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{
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int c;
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char *buffer = *addr_of_buffer;
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size_t length = *length_of_buffer;
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size_t nbytes = 0;
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size_t maxlen = max_length? *max_length : 0;
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char *p;
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if (!buffer)
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{ /* No buffer given - allocate a new one. */
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length = 256;
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buffer = xtrymalloc (length);
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*addr_of_buffer = buffer;
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if (!buffer)
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{
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*length_of_buffer = 0;
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if (max_length)
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*max_length = 0;
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return -1;
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}
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*length_of_buffer = length;
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}
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length -= 3; /* Reserve 3 bytes for CR,LF,EOL. */
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p = buffer;
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while ((c = getc (fp)) != EOF)
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{
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if (nbytes == length)
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{ /* Enlarge the buffer. */
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if (maxlen && length > maxlen) /* But not beyond our limit. */
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{
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/* Skip the rest of the line. */
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while (c != '\n' && (c=getc (fp)) != EOF)
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;
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*p++ = '\n'; /* Always append a LF (we reserved some space). */
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nbytes++;
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if (max_length)
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*max_length = 0; /* Indicate truncation. */
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break; /* the while loop. */
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}
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length += 3; /* Adjust for the reserved bytes. */
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length += length < 1024? 256 : 1024;
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*addr_of_buffer = xtryrealloc (buffer, length);
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if (!*addr_of_buffer)
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{
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int save_errno = errno;
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xfree (buffer);
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*length_of_buffer = 0;
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if (max_length)
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*max_length = 0;
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gpg_err_set_errno (save_errno);
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return -1;
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}
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buffer = *addr_of_buffer;
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*length_of_buffer = length;
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length -= 3;
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p = buffer + nbytes;
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}
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*p++ = c;
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nbytes++;
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if (c == '\n')
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break;
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}
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*p = 0; /* Make sure the line is a string. */
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return nbytes;
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}
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