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/* vi: set sw=4 ts=4: */
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* config file parser helper
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* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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* Also for use in uClibc (http://uclibc.org/) licensed under LGPLv2.1 or later.
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/* Uncomment to enable test applet */
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////config:config PARSE
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////config: bool "Uniform config file parser debugging applet: parse"
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////config: Typical usage of parse API:
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////config: char *t[3];
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////config: parser_t *p = config_open(filename);
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////config: while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
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////config: bb_error_msg("TOKENS: '%s''%s''%s'", t[0], t[1], t[2]);
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////config: config_close(p);
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////applet:IF_PARSE(APPLET(parse, BB_DIR_USR_BIN, BB_SUID_DROP))
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//kbuild:lib-y += parse_config.o
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//usage:#define parse_trivial_usage
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//usage: "[-x] [-n MAXTOKENS] [-m MINTOKENS] [-d DELIMS] [-f FLAGS] FILE..."
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//usage:#define parse_full_usage "\n\n"
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//usage: " -x Suppress output (for benchmarking)"
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#if defined ENABLE_PARSE && ENABLE_PARSE
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int parse_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int parse_main(int argc UNUSED_PARAM, char **argv)
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const char *delims = "# \t";
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unsigned flags = PARSE_NORMAL;
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int mintokens = 0, ntokens = 128;
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noout = 1 & getopt32(argv, "^" "xn:+m:+d:f:+" "\0" "-1",
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&ntokens, &mintokens, &delims, &flags
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t = xmalloc(sizeof(t[0]) * ntokens);
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parser_t *p = config_open(*argv);
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while ((n = config_read(p, t, ntokens, mintokens, delims, flags)) != 0) {
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for (int i = 0; i < n; ++i)
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parser_t* FAST_FUNC config_open2(const char *filename, FILE* FAST_FUNC (*fopen_func)(const char *path))
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fp = fopen_func(filename);
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parser = xzalloc(sizeof(*parser));
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parser_t* FAST_FUNC config_open(const char *filename)
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return config_open2(filename, fopen_or_warn_stdin);
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void FAST_FUNC config_close(parser_t *parser)
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if (PARSE_KEEP_COPY) /* compile-time constant */
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/* This function reads an entire line from a text file,
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* up to a newline, exclusive.
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* Trailing '\' is recognized as line continuation.
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* Returns -1 if EOF/error.
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static int get_line_with_continuation(parser_t *parser)
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len = getline(&parser->line, &parser->line_alloc, parser->fp);
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if (line[len - 1] == '\n')
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if (len == 0 || line[len - 1] != '\\')
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nlen = getline(&parser->nline, &parser->nline_alloc, parser->fp);
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if (parser->line_alloc < len + nlen + 1) {
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parser->line_alloc = len + nlen + 1;
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line = parser->line = xrealloc(line, parser->line_alloc);
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memcpy(&line[len], parser->nline, nlen);
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0. If parser is NULL return 0.
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1. Read a line from config file. If nothing to read then return 0.
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Handle continuation character. Advance lineno for each physical line.
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Discard everything past comment character.
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2. if PARSE_TRIM is set (default), remove leading and trailing delimiters.
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3. If resulting line is empty goto 1.
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4. Look for first delimiter. If !PARSE_COLLAPSE or !PARSE_TRIM is set then
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remember the token as empty.
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5. Else (default) if number of seen tokens is equal to max number of tokens
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(token is the last one) and PARSE_GREEDY is set then the remainder
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of the line is the last token.
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Else (token is not last or PARSE_GREEDY is not set) just replace
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first delimiter with '\0' thus delimiting the token.
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6. Advance line pointer past the end of token. If number of seen tokens
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is less than required number of tokens then goto 4.
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7. Check the number of seen tokens is not less the min number of tokens.
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Complain or die otherwise depending on PARSE_MIN_DIE.
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8. Return the number of seen tokens.
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mintokens > 0 make config_read() print error message if less than mintokens
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(but more than 0) are found. Empty lines are always skipped (not warned about).
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int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const char *delims)
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int ntokens, mintokens;
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alt_comment_ch = '\0';
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if (flags & PARSE_ALT_COMMENTS)
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alt_comment_ch = *delims++;
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ntokens = (uint8_t)flags;
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mintokens = (uint8_t)(flags >> 8);
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memset(tokens, 0, sizeof(tokens[0]) * ntokens);
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/* Read one line (handling continuations with backslash) */
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if (get_line_with_continuation(parser) < 0)
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/* Skip token in the start of line? */
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if (flags & PARSE_TRIM)
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line += strspn(line, delims + 1);
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if (flags & PARSE_WS_COMMENTS)
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p = skip_whitespace(p);
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if (p[0] == '\0' || p[0] == delims[0] || p[0] == alt_comment_ch)
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if (flags & PARSE_KEEP_COPY) {
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parser->data = xstrdup(line);
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/* Tokenize the line */
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/* Combine remaining arguments? */
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if ((t != (ntokens-1)) || !(flags & PARSE_GREEDY)) {
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/* Vanilla token, find next delimiter */
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line += strcspn(line, (delims[0] && (flags & PARSE_EOL_COMMENTS)) ? delims : delims + 1);
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/* Combining, find comment char if any */
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line = strchrnul(line, (flags & PARSE_EOL_COMMENTS) ? delims[0] : '\0');
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/* Trim any extra delimiters from the end */
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if (flags & PARSE_TRIM) {
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while (strchr(delims + 1, line[-1]) != NULL)
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/* Token not terminated? */
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if ((flags & PARSE_EOL_COMMENTS) && *line == delims[0])
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*line = '\0'; /* ends with comment char: this line is done */
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else if (*line != '\0')
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*line++ = '\0'; /* token is done, continue parsing line */
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#if 0 /* unused so far */
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if (flags & PARSE_ESCAPE) {
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strcpy_and_process_escape_sequences(tokens[t], tokens[t]);
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/* Skip possible delimiters */
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if (flags & PARSE_COLLAPSE)
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line += strspn(line, delims + 1);
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} while (*line && *line != delims[0] && t < ntokens);
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bb_error_msg("bad line %u: %d tokens found, %d needed",
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parser->lineno, t, mintokens);
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if (flags & PARSE_MIN_DIE)