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