1 /* $OpenBSD: fparseln.c,v 1.5 2004/05/28 07:03:47 deraadt Exp $ */
2 /* $NetBSD: fparseln.c,v 1.7 1999/07/02 15:49:12 simonb Exp $ */
3
4 /*
5 * Copyright (c) 2009, 2010 Thorsten Glaser
6 * Copyright (c) 1997 Christos Zoulas. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30
31 #include <stdio.h>
32 #include <string.h>
33 #include <stdlib.h>
34
35 #ifdef DEBIAN
36 #define NEED_FPARSELN_DECL
37 #include "mbsdtree.h"
38 #else
39 #include "util.h"
40 #endif
41
42 __RCSID("$MirOS: src/lib/libutil/fparseln.c,v 1.4 2010/03/16 22:26:11 tg Exp $");
43
44 static int isescaped(const char *, const char *, int);
45
46 /* isescaped():
47 * Return true if the character in *p that belongs to a string
48 * that starts in *sp, is escaped by the escape character esc.
49 */
50 static int
isescaped(const char * sp,const char * p,int esc)51 isescaped(const char *sp, const char *p, int esc)
52 {
53 const char *cp;
54 size_t ne;
55
56 /* No escape character */
57 if (esc == '\0')
58 return 1;
59
60 /* Count the number of escape characters that precede ours */
61 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++)
62 continue;
63
64 /* Return true if odd number of escape characters */
65 return (ne & 1) != 0;
66 }
67
68
69 /* fparseln():
70 * Read a line from a file parsing continuations ending in \
71 * and eliminating trailing newlines, or comments starting with
72 * the comment char.
73 */
74 char *
fparseln(FILE * fp,size_t * size,size_t * lineno,const char str[3],int flags)75 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3],
76 int flags)
77 {
78 static const char dstr[3] = { '\\', '\\', '#' };
79 char *buf = NULL, *ptr, *cp, esc, con, nl, com;
80 size_t s, len = 0;
81 int cnt = 1;
82
83 if (str == NULL)
84 str = dstr;
85
86 esc = str[0];
87 con = str[1];
88 com = str[2];
89
90 /*
91 * XXX: it would be cool to be able to specify the newline character,
92 * but unfortunately, fgetln does not let us
93 */
94 nl = '\n';
95
96 while (cnt) {
97 cnt = 0;
98
99 if (lineno)
100 (*lineno)++;
101
102 if ((ptr = fgetln(fp, &s)) == NULL)
103 break;
104
105 if (s && com) { /* Check and eliminate comments */
106 for (cp = ptr; cp < ptr + s; cp++)
107 if (*cp == com && !isescaped(ptr, cp, esc)) {
108 s = cp - ptr;
109 cnt = s == 0 && buf == NULL;
110 break;
111 }
112 }
113
114 if (s && nl) { /* Check and eliminate newlines */
115 cp = &ptr[s - 1];
116
117 if (*cp == nl)
118 s--; /* forget newline */
119 }
120
121 if (s && con) { /* Check and eliminate continuations */
122 cp = &ptr[s - 1];
123
124 if (*cp == con && !isescaped(ptr, cp, esc)) {
125 s--; /* forget escape */
126 cnt = 1;
127 }
128 }
129
130 if (s == 0 && buf != NULL)
131 continue;
132
133 if ((cp = realloc(buf, len + s + 1)) == NULL) {
134 free(buf);
135 return NULL;
136 }
137 buf = cp;
138
139 (void) memcpy(buf + len, ptr, s);
140 len += s;
141 buf[len] = '\0';
142 }
143
144 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL &&
145 strchr(buf, esc) != NULL) {
146 ptr = cp = buf;
147 while (cp[0] != '\0') {
148 int skipesc;
149
150 while (cp[0] != '\0' && cp[0] != esc)
151 *ptr++ = *cp++;
152 if (cp[0] == '\0' || cp[1] == '\0')
153 break;
154
155 skipesc = 0;
156 if (cp[1] == com)
157 skipesc += (flags & FPARSELN_UNESCCOMM);
158 if (cp[1] == con)
159 skipesc += (flags & FPARSELN_UNESCCONT);
160 if (cp[1] == esc)
161 skipesc += (flags & FPARSELN_UNESCESC);
162 if (cp[1] != com && cp[1] != con && cp[1] != esc)
163 skipesc = (flags & FPARSELN_UNESCREST);
164
165 if (skipesc)
166 cp++;
167 else
168 *ptr++ = *cp++;
169 *ptr++ = *cp++;
170 }
171 *ptr = '\0';
172 len = strlen(buf);
173 }
174
175 if (size)
176 *size = len;
177 return buf;
178 }
179
180 #ifdef TEST
181
182 int main(int, char **);
183
184 int
main(argc,argv)185 main(argc, argv)
186 int argc;
187 char **argv;
188 {
189 char *ptr;
190 size_t size, line;
191
192 line = 0;
193 while ((ptr = fparseln(stdin, &size, &line, NULL,
194 FPARSELN_UNESCALL)) != NULL)
195 printf("line %d (%d) |%s|\n", line, size, ptr);
196 return 0;
197 }
198
199 /*
200
201 # This is a test
202 line 1
203 line 2 \
204 line 3 # Comment
205 line 4 \# Not comment \\\\
206
207 # And a comment \
208 line 5 \\\
209 line 6
210
211 */
212
213 #endif /* TEST */
214