1 /* vi: set sw=4 ts=4: */
2 /*
3 * config file parser helper
4 *
5 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 * Also for use in uClibc (http://uclibc.org/) licensed under LGPLv2.1 or later.
9 */
10
11 /* Uncomment to enable test applet */
12 ////config:config PARSE
13 ////config: bool "Uniform config file parser debugging applet: parse"
14 ////config: default n
15 ////config: help
16 ////config: Typical usage of parse API:
17 ////config: char *t[3];
18 ////config: parser_t *p = config_open(filename);
19 ////config: while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
20 ////config: bb_error_msg("TOKENS: '%s''%s''%s'", t[0], t[1], t[2]);
21 ////config: }
22 ////config: config_close(p);
23
24 ////applet:IF_PARSE(APPLET(parse, BB_DIR_USR_BIN, BB_SUID_DROP))
25
26 //kbuild:lib-y += parse_config.o
27
28 //usage:#define parse_trivial_usage
29 //usage: "[-x] [-n MAXTOKENS] [-m MINTOKENS] [-d DELIMS] [-f FLAGS] FILE..."
30 //usage:#define parse_full_usage "\n\n"
31 //usage: " -x Suppress output (for benchmarking)"
32
33 #include "libbb.h"
34
35 #if defined ENABLE_PARSE && ENABLE_PARSE
36 int parse_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
parse_main(int argc UNUSED_PARAM,char ** argv)37 int parse_main(int argc UNUSED_PARAM, char **argv)
38 {
39 const char *delims = "# \t";
40 char **t;
41 unsigned flags = PARSE_NORMAL;
42 int mintokens = 0, ntokens = 128;
43 unsigned noout;
44
45 noout = 1 & getopt32(argv, "^" "xn:+m:+d:f:+" "\0" "-1",
46 &ntokens, &mintokens, &delims, &flags
47 );
48 //argc -= optind;
49 argv += optind;
50
51 t = xmalloc(sizeof(t[0]) * ntokens);
52 while (*argv) {
53 int n;
54 parser_t *p = config_open(*argv);
55 while ((n = config_read(p, t, ntokens, mintokens, delims, flags)) != 0) {
56 if (!noout) {
57 for (int i = 0; i < n; ++i)
58 printf("[%s]", t[i]);
59 puts("");
60 }
61 }
62 config_close(p);
63 argv++;
64 }
65 return EXIT_SUCCESS;
66 }
67 #endif
68
config_open2(const char * filename,FILE * FAST_FUNC (* fopen_func)(const char * path))69 parser_t* FAST_FUNC config_open2(const char *filename, FILE* FAST_FUNC (*fopen_func)(const char *path))
70 {
71 FILE* fp;
72 parser_t *parser;
73
74 fp = fopen_func(filename);
75 if (!fp)
76 return NULL;
77 parser = xzalloc(sizeof(*parser));
78 parser->fp = fp;
79 return parser;
80 }
81
config_open(const char * filename)82 parser_t* FAST_FUNC config_open(const char *filename)
83 {
84 return config_open2(filename, fopen_or_warn_stdin);
85 }
86
config_close(parser_t * parser)87 void FAST_FUNC config_close(parser_t *parser)
88 {
89 if (parser) {
90 if (PARSE_KEEP_COPY) /* compile-time constant */
91 free(parser->data);
92 fclose(parser->fp);
93 free(parser->line);
94 free(parser->nline);
95 free(parser);
96 }
97 }
98
99 /* This function reads an entire line from a text file,
100 * up to a newline, exclusive.
101 * Trailing '\' is recognized as line continuation.
102 * Returns -1 if EOF/error.
103 */
get_line_with_continuation(parser_t * parser)104 static int get_line_with_continuation(parser_t *parser)
105 {
106 ssize_t len, nlen;
107 char *line;
108
109 len = getline(&parser->line, &parser->line_alloc, parser->fp);
110 if (len <= 0)
111 return len;
112
113 line = parser->line;
114 for (;;) {
115 parser->lineno++;
116 if (line[len - 1] == '\n')
117 len--;
118 if (len == 0 || line[len - 1] != '\\')
119 break;
120 len--;
121
122 nlen = getline(&parser->nline, &parser->nline_alloc, parser->fp);
123 if (nlen <= 0)
124 break;
125
126 if (parser->line_alloc < len + nlen + 1) {
127 parser->line_alloc = len + nlen + 1;
128 line = parser->line = xrealloc(line, parser->line_alloc);
129 }
130 memcpy(&line[len], parser->nline, nlen);
131 len += nlen;
132 }
133
134 line[len] = '\0';
135 return len;
136 }
137
138
139 /*
140 0. If parser is NULL return 0.
141 1. Read a line from config file. If nothing to read then return 0.
142 Handle continuation character. Advance lineno for each physical line.
143 Discard everything past comment character.
144 2. if PARSE_TRIM is set (default), remove leading and trailing delimiters.
145 3. If resulting line is empty goto 1.
146 4. Look for first delimiter. If !PARSE_COLLAPSE or !PARSE_TRIM is set then
147 remember the token as empty.
148 5. Else (default) if number of seen tokens is equal to max number of tokens
149 (token is the last one) and PARSE_GREEDY is set then the remainder
150 of the line is the last token.
151 Else (token is not last or PARSE_GREEDY is not set) just replace
152 first delimiter with '\0' thus delimiting the token.
153 6. Advance line pointer past the end of token. If number of seen tokens
154 is less than required number of tokens then goto 4.
155 7. Check the number of seen tokens is not less the min number of tokens.
156 Complain or die otherwise depending on PARSE_MIN_DIE.
157 8. Return the number of seen tokens.
158
159 mintokens > 0 make config_read() print error message if less than mintokens
160 (but more than 0) are found. Empty lines are always skipped (not warned about).
161 */
162 #undef config_read
config_read(parser_t * parser,char ** tokens,unsigned flags,const char * delims)163 int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const char *delims)
164 {
165 char *line, *p;
166 int ntokens, mintokens;
167 int t;
168 char alt_comment_ch;
169
170 if (!parser)
171 return 0;
172
173 alt_comment_ch = '\0';
174 if (flags & PARSE_ALT_COMMENTS)
175 alt_comment_ch = *delims++;
176
177 ntokens = (uint8_t)flags;
178 mintokens = (uint8_t)(flags >> 8);
179
180 again:
181 memset(tokens, 0, sizeof(tokens[0]) * ntokens);
182
183 /* Read one line (handling continuations with backslash) */
184 if (get_line_with_continuation(parser) < 0)
185 return 0;
186
187 line = parser->line;
188
189 /* Skip token in the start of line? */
190 if (flags & PARSE_TRIM)
191 line += strspn(line, delims + 1);
192
193 p = line;
194 if (flags & PARSE_WS_COMMENTS)
195 p = skip_whitespace(p);
196 if (p[0] == '\0' || p[0] == delims[0] || p[0] == alt_comment_ch)
197 goto again;
198
199 if (flags & PARSE_KEEP_COPY) {
200 free(parser->data);
201 parser->data = xstrdup(line);
202 }
203
204 /* Tokenize the line */
205 t = 0;
206 do {
207 /* Pin token */
208 tokens[t] = line;
209
210 /* Combine remaining arguments? */
211 if ((t != (ntokens-1)) || !(flags & PARSE_GREEDY)) {
212 /* Vanilla token, find next delimiter */
213 line += strcspn(line, (delims[0] && (flags & PARSE_EOL_COMMENTS)) ? delims : delims + 1);
214 } else {
215 /* Combining, find comment char if any */
216 line = strchrnul(line, (flags & PARSE_EOL_COMMENTS) ? delims[0] : '\0');
217
218 /* Trim any extra delimiters from the end */
219 if (flags & PARSE_TRIM) {
220 while (strchr(delims + 1, line[-1]) != NULL)
221 line--;
222 }
223 }
224
225 /* Token not terminated? */
226 if ((flags & PARSE_EOL_COMMENTS) && *line == delims[0])
227 *line = '\0'; /* ends with comment char: this line is done */
228 else if (*line != '\0')
229 *line++ = '\0'; /* token is done, continue parsing line */
230
231 #if 0 /* unused so far */
232 if (flags & PARSE_ESCAPE) {
233 strcpy_and_process_escape_sequences(tokens[t], tokens[t]);
234 }
235 #endif
236 /* Skip possible delimiters */
237 if (flags & PARSE_COLLAPSE)
238 line += strspn(line, delims + 1);
239
240 t++;
241 } while (*line && *line != delims[0] && t < ntokens);
242
243 if (t < mintokens) {
244 bb_error_msg("bad line %u: %d tokens found, %d needed",
245 parser->lineno, t, mintokens);
246 if (flags & PARSE_MIN_DIE)
247 xfunc_die();
248 goto again;
249 }
250
251 return t;
252 }
253