1 | /* mini man implementation for busybox
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2 | * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
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3 | * Licensed under GPLv2, see file LICENSE in this source tree.
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4 | */
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5 |
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6 | //usage:#define man_trivial_usage
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7 | //usage: "[-aw] [MANPAGE]..."
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8 | //usage:#define man_full_usage "\n\n"
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9 | //usage: "Format and display manual page\n"
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10 | //usage: "\n -a Display all pages"
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11 | //usage: "\n -w Show page locations"
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12 |
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13 | #include "libbb.h"
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14 |
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15 | enum {
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16 | OPT_a = 1, /* all */
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17 | OPT_w = 2, /* print path */
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18 | };
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19 |
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20 | /* This is what I see on my desktop system being executed:
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21 |
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22 | (
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23 | echo ".ll 12.4i"
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24 | echo ".nr LL 12.4i"
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25 | echo ".pl 1100i"
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26 | gunzip -c '/usr/man/man1/bzip2.1.gz'
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27 | echo ".\\\""
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28 | echo ".pl \n(nlu+10"
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29 | ) | gtbl | nroff -Tlatin1 -mandoc | less
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30 |
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31 | */
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32 |
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33 | static int show_manpage(const char *pager, char *man_filename, int man, int level);
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34 |
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35 | static int run_pipe(const char *pager, char *man_filename, int man, int level)
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36 | {
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37 | char *cmd;
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38 |
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39 | /* Prevent man page link loops */
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40 | if (level > 10)
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41 | return 0;
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42 |
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43 | if (access(man_filename, R_OK) != 0)
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44 | return 0;
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45 |
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46 | if (option_mask32 & OPT_w) {
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47 | puts(man_filename);
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48 | return 1;
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49 | }
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50 |
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51 | if (man) { /* man page, not cat page */
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52 | /* Is this a link to another manpage? */
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53 | /* The link has the following on the first line: */
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54 | /* ".so another_man_page" */
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55 |
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56 | struct stat sb;
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57 | char *line;
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58 | char *linkname, *p;
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59 |
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60 | /* On my system:
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61 | * man1/genhostid.1.gz: 203 bytes - smallest real manpage
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62 | * man2/path_resolution.2.gz: 114 bytes - largest link
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63 | */
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64 | xstat(man_filename, &sb);
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65 | if (sb.st_size > 300) /* err on the safe side */
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66 | goto ordinary_manpage;
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67 |
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68 | line = xmalloc_open_zipped_read_close(man_filename, NULL);
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69 | if (!line || strncmp(line, ".so ", 4) != 0) {
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70 | free(line);
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71 | goto ordinary_manpage;
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72 | }
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73 | /* Example: man2/path_resolution.2.gz contains
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74 | * ".so man7/path_resolution.7\n<junk>"
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75 | */
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76 | *strchrnul(line, '\n') = '\0';
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77 | linkname = skip_whitespace(&line[4]);
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78 |
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79 | /* If link has no slashes, we just replace man page name.
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80 | * If link has slashes (however many), we go back *once*.
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81 | * ".so zzz/ggg/page.3" does NOT go back two levels. */
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82 | p = strrchr(man_filename, '/');
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83 | if (!p)
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84 | goto ordinary_manpage;
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85 | *p = '\0';
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86 | if (strchr(linkname, '/')) {
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87 | p = strrchr(man_filename, '/');
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88 | if (!p)
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89 | goto ordinary_manpage;
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90 | *p = '\0';
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91 | }
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92 |
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93 | /* Links do not have .gz extensions, even if manpage
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94 | * is compressed */
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95 | man_filename = xasprintf("%s/%s", man_filename, linkname);
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96 | free(line);
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97 | /* Note: we leak "new" man_filename string as well... */
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98 | if (show_manpage(pager, man_filename, man, level + 1))
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99 | return 1;
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100 | /* else: show the link, it's better than nothing */
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101 | }
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102 |
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103 | ordinary_manpage:
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104 | close(STDIN_FILENO);
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105 | open_zipped(man_filename); /* guaranteed to use fd 0 (STDIN_FILENO) */
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106 | /* "2>&1" is added so that nroff errors are shown in pager too.
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107 | * Otherwise it may show just empty screen */
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108 | cmd = xasprintf(
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109 | man ? "gtbl | nroff -Tlatin1 -mandoc 2>&1 | %s"
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110 | : "%s",
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111 | pager);
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112 | system(cmd);
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113 | free(cmd);
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114 | return 1;
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115 | }
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116 |
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117 | /* man_filename is of the form "/dir/dir/dir/name.s" */
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118 | static int show_manpage(const char *pager, char *man_filename, int man, int level)
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119 | {
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120 | #if SEAMLESS_COMPRESSION
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121 | /* We leak this allocation... */
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122 | char *filename_with_zext = xasprintf("%s.lzma", man_filename);
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123 | char *ext = strrchr(filename_with_zext, '.') + 1;
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124 | #endif
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125 |
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126 | #if ENABLE_FEATURE_SEAMLESS_LZMA
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127 | if (run_pipe(pager, filename_with_zext, man, level))
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128 | return 1;
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129 | #endif
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130 | #if ENABLE_FEATURE_SEAMLESS_XZ
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131 | strcpy(ext, "xz");
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132 | if (run_pipe(pager, filename_with_zext, man, level))
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133 | return 1;
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134 | #endif
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135 | #if ENABLE_FEATURE_SEAMLESS_BZ2
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136 | strcpy(ext, "bz2");
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137 | if (run_pipe(pager, filename_with_zext, man, level))
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138 | return 1;
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139 | #endif
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140 | #if ENABLE_FEATURE_SEAMLESS_GZ
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141 | strcpy(ext, "gz");
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142 | if (run_pipe(pager, filename_with_zext, man, level))
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143 | return 1;
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144 | #endif
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145 |
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146 | return run_pipe(pager, man_filename, man, level);
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147 | }
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148 |
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149 | int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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150 | int man_main(int argc UNUSED_PARAM, char **argv)
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151 | {
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152 | parser_t *parser;
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153 | const char *pager;
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154 | char **man_path_list;
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155 | char *sec_list;
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156 | char *cur_path, *cur_sect;
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157 | int count_mp, cur_mp;
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158 | int opt, not_found;
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159 | char *token[2];
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160 |
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161 | opt_complementary = "-1"; /* at least one argument */
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162 | opt = getopt32(argv, "+aw");
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163 | argv += optind;
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164 |
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165 | sec_list = xstrdup("1:2:3:4:5:6:7:8:9");
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166 | /* Last valid man_path_list[] is [0x10] */
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167 | count_mp = 0;
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168 | man_path_list = xzalloc(0x11 * sizeof(man_path_list[0]));
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169 | man_path_list[0] = getenv("MANPATH");
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170 | if (!man_path_list[0]) /* default, may be overridden by /etc/man.conf */
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171 | man_path_list[0] = (char*)"/usr/man";
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172 | else
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173 | count_mp++;
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174 | pager = getenv("MANPAGER");
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175 | if (!pager) {
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176 | pager = getenv("PAGER");
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177 | if (!pager)
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178 | pager = "more";
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179 | }
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180 |
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181 | /* Parse man.conf[ig] or man_db.conf */
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182 | /* man version 1.6f uses man.config */
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183 | /* man-db implementation of man uses man_db.conf */
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184 | parser = config_open2("/etc/man.config", fopen_for_read);
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185 | if (!parser)
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186 | parser = config_open2("/etc/man.conf", fopen_for_read);
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187 | if (!parser)
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188 | parser = config_open2("/etc/man_db.conf", fopen_for_read);
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189 |
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190 | while (config_read(parser, token, 2, 0, "# \t", PARSE_NORMAL)) {
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191 | if (!token[1])
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192 | continue;
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193 | if (strcmp("MANDATORY_MANPATH"+10, token[0]) == 0 /* "MANPATH"? */
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194 | || strcmp("MANDATORY_MANPATH", token[0]) == 0
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195 | ) {
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196 | char *path = token[1];
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197 | while (*path) {
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198 | char *next_path;
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199 | char **path_element;
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200 |
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201 | next_path = strchr(path, ':');
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202 | if (next_path) {
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203 | *next_path = '\0';
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204 | if (next_path++ == path) /* "::"? */
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205 | goto next;
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206 | }
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207 | /* Do we already have path? */
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208 | path_element = man_path_list;
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209 | while (*path_element) {
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210 | if (strcmp(*path_element, path) == 0)
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211 | goto skip;
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212 | path_element++;
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213 | }
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214 | man_path_list = xrealloc_vector(man_path_list, 4, count_mp);
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215 | man_path_list[count_mp] = xstrdup(path);
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216 | count_mp++;
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217 | /* man_path_list is NULL terminated */
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218 | /*man_path_list[count_mp] = NULL; - xrealloc_vector did it */
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219 | skip:
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220 | if (!next_path)
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221 | break;
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222 | next:
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223 | path = next_path;
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224 | }
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225 | }
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226 | if (strcmp("MANSECT", token[0]) == 0) {
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227 | free(sec_list);
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228 | sec_list = xstrdup(token[1]);
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229 | }
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230 | }
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231 | config_close(parser);
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232 |
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233 | not_found = 0;
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234 | do { /* for each argv[] */
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235 | int found = 0;
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236 | cur_mp = 0;
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237 |
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238 | if (strchr(*argv, '/')) {
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239 | found = show_manpage(pager, *argv, /*man:*/ 1, 0);
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240 | goto check_found;
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241 | }
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242 | while ((cur_path = man_path_list[cur_mp++]) != NULL) {
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243 | /* for each MANPATH */
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244 | cur_sect = sec_list;
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245 | do { /* for each section */
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246 | char *next_sect = strchrnul(cur_sect, ':');
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247 | int sect_len = next_sect - cur_sect;
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248 | char *man_filename;
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249 | int cat0man1 = 0;
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250 |
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251 | /* Search for cat, then man page */
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252 | while (cat0man1 < 2) {
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253 | int found_here;
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254 | man_filename = xasprintf("%s/%s%.*s/%s.%.*s",
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255 | cur_path,
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256 | "cat\0man" + (cat0man1 * 4),
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257 | sect_len, cur_sect,
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258 | *argv,
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259 | sect_len, cur_sect);
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260 | found_here = show_manpage(pager, man_filename, cat0man1, 0);
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261 | found |= found_here;
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262 | cat0man1 += found_here + 1;
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263 | free(man_filename);
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264 | }
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265 |
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266 | if (found && !(opt & OPT_a))
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267 | goto next_arg;
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268 | cur_sect = next_sect;
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269 | while (*cur_sect == ':')
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270 | cur_sect++;
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271 | } while (*cur_sect);
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272 | }
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273 | check_found:
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274 | if (!found) {
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275 | bb_error_msg("no manual entry for '%s'", *argv);
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276 | not_found = 1;
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277 | }
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278 | next_arg:
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279 | argv++;
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280 | } while (*argv);
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281 |
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282 | return not_found;
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283 | }
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