miscutils/man.c

   1 /* mini man implementation for busybox
   2  * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
   3  * Licensed under GPLv2, see file LICENSE in this tarball for details.
   4  */
   5
   6 #include "libbb.h"
   7
   8 enum {
   9         OPT_a = 1, /* all */
  10         OPT_w = 2, /* print path */
  11 };
  12
  13 /* This is what I see on my desktop system being executed:
  14
  15 (
  16 echo ".ll 12.4i"
  17 echo ".nr LL 12.4i"
  18 echo ".pl 1100i"
  19 gunzip -c '/usr/man/man1/bzip2.1.gz'
  20 echo ".\\\""
  21 echo ".pl \n(nlu+10"
  22 ) | gtbl | nroff -Tlatin1 -mandoc | less
  23
  24 */
  25
  26 static int run_pipe(const char *unpacker, const char *pager, char *man_filename)
  27 {
  28         char *cmd;
  29
  30         if (access(man_filename, R_OK) != 0)
  31                 return 0;
  32
  33         if (option_mask32 & OPT_w) {
  34                 puts(man_filename);
  35                 return 1;
  36         }
  37
  38         cmd = xasprintf("%s '%s' | gtbl | nroff -Tlatin1 -mandoc | %s",
  39                         unpacker, man_filename, pager);
  40         system(cmd);
  41         free(cmd);
  42         return 1;
  43 }
  44
  45 /* man_filename is of the form "/dir/dir/dir/name.s.bz2" */
  46 static int show_manpage(const char *pager, char *man_filename)
  47 {
  48         int len;
  49
  50         if (run_pipe("bunzip2 -c", pager, man_filename))
  51                 return 1;
  52
  53         len = strlen(man_filename) - 1;
  54
  55         man_filename[len] = '\0'; /* ".bz2" -> ".gz" */
  56         man_filename[len - 2] = 'g';
  57         if (run_pipe("gunzip -c", pager, man_filename))
  58                 return 1;
  59
  60         man_filename[len - 3] = '\0'; /* ".gz" -> "" */
  61         if (run_pipe("cat", pager, man_filename))
  62                 return 1;
  63
  64         return 0;
  65 }
  66
  67 int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  68 int man_main(int argc ATTRIBUTE_UNUSED, char **argv)
  69 {
  70         FILE *cf;
  71         const char *pager;
  72         char **man_path_list;
  73         char *sec_list;
  74         char *cur_path, *cur_sect;
  75         char *line, *value;
  76         int count_mp, alloc_mp, cur_mp;
  77         int opt, not_found;
  78
  79         opt_complementary = "-1"; /* at least one argument */
  80         opt = getopt32(argv, "+aw");
  81         argv += optind;
  82
  83         sec_list = xstrdup("1:2:3:4:5:6:7:8:9");
  84         alloc_mp = 10;
  85         man_path_list = xmalloc(10 * sizeof(man_path_list[0]));
  86         count_mp = 0;
  87         man_path_list[0] = xstrdup(getenv("MANPATH"));
  88         if (man_path_list[0])
  89                 count_mp++;
  90         pager = getenv("MANPAGER");
  91         if (!pager) {
  92                 pager = getenv("PAGER");
  93                 if (!pager)
  94                         pager = "more";
  95         }
  96
  97         /* Parse man.conf */
  98         cf = fopen_or_warn("/etc/man.conf", "r");
  99         if (cf) {
 100                 /* go through man configuration file and search relevant paths, sections */
 101                 while ((line = xmalloc_fgetline(cf)) != NULL) {
 102                         trim(line); /* remove whitespace at the beginning/end */
 103                         if (isspace(line[7])) {
 104                                 line[7] = '\0';
 105                                 value = skip_whitespace(&line[8]);
 106                                 *skip_non_whitespace(value) = '\0';
 107                                 if (strcmp("MANPATH", line) == 0) {
 108                                         man_path_list[count_mp] = xstrdup(value);
 109                                         count_mp++;
 110                                         if (alloc_mp == count_mp) {
 111                                                 alloc_mp += 10;
 112                                                 man_path_list = xrealloc(man_path_list, alloc_mp * sizeof(man_path_list[0]));
 113                                         }
 114                                         /* thus man_path_list is always NULL terminated */
 115                                 }
 116                                 if (strcmp("MANSECT", line) == 0) {
 117                                         free(sec_list);
 118                                         sec_list = xstrdup(value);
 119                                 }
 120                         }
 121                         free(line);
 122                 }
 123                 fclose(cf);
 124         }
 125
 126         not_found = 0;
 127         do { /* for each argv[] */
 128                 int found = 0;
 129                 cur_mp = 0;
 130                 while ((cur_path = man_path_list[cur_mp++]) != NULL) {
 131                         /* for each MANPATH */
 132                         do { /* for each MANPATH item */
 133                                 char *next_path = strchrnul(cur_path, ':');
 134                                 int path_len = next_path - cur_path;
 135                                 cur_sect = sec_list;
 136                                 do { /* for each section */
 137                                         char *next_sect = strchrnul(cur_sect, ':');
 138                                         int sect_len = next_sect - cur_sect;
 139
 140                                         char *man_filename = xasprintf("%.*s/man%.*s/%s.%.*s" ".bz2",
 141                                                                 path_len, cur_path,
 142                                                                 sect_len, cur_sect,
 143                                                                 *argv,
 144                                                                 sect_len, cur_sect);
 145                                         found |= show_manpage(pager, man_filename);
 146                                         free(man_filename);
 147                                         if (found && !(opt & OPT_a))
 148                                                 goto next_arg;
 149                                         cur_sect = next_sect;
 150                                         while (*cur_sect == ':')
 151                                                 cur_sect++;
 152                                 } while (*cur_sect);
 153                                 cur_path = next_path;
 154                                 while (*cur_path == ':')
 155                                         cur_path++;
 156                         } while (*cur_path);
 157                 }
 158                 if (!found) {
 159                         bb_error_msg("no manual entry for '%s'", *argv);
 160                         not_found = 1;
 161                 }
 162  next_arg:
 163                 argv++;
 164         } while (*argv);
 165
 166         return not_found;
 167 }