Ventoy/SQUASHFS/squashfs-tools-4.4/squashfs-tools/read_file.c

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2020-04-04 12:07:50 -04:00
/*
* Create a squashfs filesystem. This is a highly compressed read only
* filesystem.
*
* Copyright (c) 2012
* Phillip Lougher <phillip@squashfs.org.uk>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* read_file.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include "error.h"
#define TRUE 1
#define FALSE 0
#define MAX_LINE 16384
/*
* Read file, passing each line to parse_line() for
* parsing.
*
* Lines can be split across multiple lines using "\".
*
* Blank lines and comment lines indicated by # are supported.
*/
int read_file(char *filename, char *type, int (parse_line)(char *))
{
FILE *fd;
char *def, *err, *line = NULL;
int res, size = 0;
fd = fopen(filename, "r");
if(fd == NULL) {
ERROR("Could not open %s device file \"%s\" because %s\n",
type, filename, strerror(errno));
return FALSE;
}
while(1) {
int total = 0;
while(1) {
int len;
if(total + (MAX_LINE + 1) > size) {
line = realloc(line, size += (MAX_LINE + 1));
if(line == NULL)
MEM_ERROR();
}
err = fgets(line + total, MAX_LINE + 1, fd);
if(err == NULL)
break;
len = strlen(line + total);
total += len;
if(len == MAX_LINE && line[total - 1] != '\n') {
/* line too large */
ERROR("Line too long when reading "
"%s file \"%s\", larger than "
"%d bytes\n", type, filename, MAX_LINE);
goto failed;
}
/*
* Remove '\n' terminator if it exists (the last line
* in the file may not be '\n' terminated)
*/
if(len && line[total - 1] == '\n') {
line[-- total] = '\0';
len --;
}
/*
* If no line continuation then jump out to
* process line. Note, we have to be careful to
* check for "\\" (backslashed backslash) and to
* ensure we don't look at the previous line
*/
if(len == 0 || line[total - 1] != '\\' || (len >= 2 &&
strcmp(line + total - 2, "\\\\") == 0))
break;
else
total --;
}
if(err == NULL) {
if(ferror(fd)) {
ERROR("Reading %s file \"%s\" failed "
"because %s\n", type, filename,
strerror(errno));
goto failed;
}
/*
* At EOF, normally we'll be finished, but, have to
* check for special case where we had "\" line
* continuation and then hit EOF immediately afterwards
*/
if(total == 0)
break;
else
line[total] = '\0';
}
/* Skip any leading whitespace */
for(def = line; isspace(*def); def ++);
/* if line is now empty after skipping characters, skip it */
if(*def == '\0')
continue;
/* if comment line, skip */
if(*def == '#')
continue;
res = parse_line(def);
if(res == FALSE)
goto failed;
}
fclose(fd);
free(line);
return TRUE;
failed:
fclose(fd);
free(line);
return FALSE;
}