1/*
2 * Create a squashfs filesystem.  This is a highly compressed read only
3 * filesystem.
4 *
5 * Copyright (c) 2012
6 * Phillip Lougher <phillip@squashfs.org.uk>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2,
11 * or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 *
22 * read_file.c
23 */
24
25#include <stdio.h>
26#include <stdlib.h>
27#include <string.h>
28#include <ctype.h>
29#include <errno.h>
30
31#include "error.h"
32
33#define TRUE 1
34#define FALSE 0
35#define MAX_LINE 16384
36
37/*
38 * Read file, passing each line to parse_line() for
39 * parsing.
40 *
41 * Lines can be split across multiple lines using "\".
42 *
43 * Blank lines and comment lines indicated by # are supported.
44 */
45int read_file(char *filename, char *type, int (parse_line)(char *))
46{
47	FILE *fd;
48	char *def, *err, *line = NULL;
49	int res, size = 0;
50
51	fd = fopen(filename, "r");
52	if(fd == NULL) {
53		ERROR("Could not open %s device file \"%s\" because %s\n",
54			type, filename, strerror(errno));
55		return FALSE;
56	}
57
58	while(1) {
59		int total = 0;
60
61		while(1) {
62			int len;
63
64			if(total + (MAX_LINE + 1) > size) {
65				line = realloc(line, size += (MAX_LINE + 1));
66				if(line == NULL)
67					MEM_ERROR();
68			}
69
70			err = fgets(line + total, MAX_LINE + 1, fd);
71			if(err == NULL)
72				break;
73
74			len = strlen(line + total);
75			total += len;
76
77			if(len == MAX_LINE && line[total - 1] != '\n') {
78				/* line too large */
79				ERROR("Line too long when reading "
80					"%s file \"%s\", larger than "
81					"%d bytes\n", type, filename, MAX_LINE);
82				goto failed;
83			}
84
85			/*
86			 * Remove '\n' terminator if it exists (the last line
87			 * in the file may not be '\n' terminated)
88			 */
89			if(len && line[total - 1] == '\n') {
90				line[-- total] = '\0';
91				len --;
92			}
93
94			/*
95			 * If no line continuation then jump out to
96			 * process line.  Note, we have to be careful to
97			 * check for "\\" (backslashed backslash) and to
98			 * ensure we don't look at the previous line
99			 */
100			if(len == 0 || line[total - 1] != '\\' || (len >= 2 &&
101					strcmp(line + total - 2, "\\\\") == 0))
102				break;
103			else
104				total --;
105		}
106
107		if(err == NULL) {
108			if(ferror(fd)) {
109                		ERROR("Reading %s file \"%s\" failed "
110					"because %s\n", type, filename,
111					strerror(errno));
112				goto failed;
113			}
114
115			/*
116			 * At EOF, normally we'll be finished, but, have to
117			 * check for special case where we had "\" line
118			 * continuation and then hit EOF immediately afterwards
119			 */
120			if(total == 0)
121				break;
122			else
123				line[total] = '\0';
124		}
125
126		/* Skip any leading whitespace */
127		for(def = line; isspace(*def); def ++);
128
129		/* if line is now empty after skipping characters, skip it */
130		if(*def == '\0')
131			continue;
132
133		/* if comment line, skip */
134		if(*def == '#')
135			continue;
136
137		res = parse_line(def);
138		if(res == FALSE)
139			goto failed;
140	}
141
142	fclose(fd);
143	free(line);
144	return TRUE;
145
146failed:
147	fclose(fd);
148	free(line);
149	return FALSE;
150}
151