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 source tree.
4 */
5 //config:config MAN
6 //config: bool "man (26 kb)"
7 //config: default y
8 //config: help
9 //config: Format and display manual pages.
10
11 //applet:IF_MAN(APPLET(man, BB_DIR_USR_BIN, BB_SUID_DROP))
12
13 //kbuild:lib-$(CONFIG_MAN) += man.o
14
15 //usage:#define man_trivial_usage
16 //usage: "[-aw] [SECTION] MANPAGE[.SECTION]..."
17 //usage:#define man_full_usage "\n\n"
18 //usage: "Display manual page\n"
19 //usage: "\n -a Display all pages"
20 //usage: "\n -w Show page locations"
21 //usage: "\n"
22 //usage: "\n$COLUMNS overrides output width"
23
24 #include "libbb.h"
25 #include "common_bufsiz.h"
26
27 enum {
28 OPT_a = 1, /* all */
29 OPT_w = 2, /* print path */
30 };
31
32 /* This is what I see on my desktop system being executed:
33 (
34 echo ".ll 12.4i"
35 echo ".nr LL 12.4i"
36 echo ".pl 1100i"
37 gunzip -c '/usr/man/man1/bzip2.1.gz'
38 echo ".\\\""
39 echo ".pl \n(nlu+10"
40 ) | gtbl | nroff -Tlatin1 -mandoc | less
41
42 Some systems use -Tascii.
43
44 On another system I see this:
45
46 ... | tbl | nroff -mandoc -rLL=<NNN>n -rLT=<NNN>n -Tutf8 | less
47
48 where <NNN> is screen width minus 5.
49 Replacing "DEFINE nroff nroff -mandoc" in /etc/man_db.conf
50 changes "nroff -mandoc" part; -rLL=<NNN>n, -rLT=<NNN>n and -Tutf8 parts are
51 appended to the user-specified command.
52
53 Redirecting to a pipe or file sets GROFF_NO_SGR=1 to prevent color escapes,
54 and uses "col -b -p -x" instead of pager, this filters out backspace
55 and underscore tricks.
56 */
57
58 struct globals {
59 const char *col;
60 const char *tbl;
61 const char *nroff;
62 const char *pager;
63 } FIX_ALIASING;
64 #define G (*(struct globals*)bb_common_bufsiz1)
65 #define INIT_G() do { \
66 setup_common_bufsiz(); \
67 G.col = "col"; \
68 G.tbl = "tbl"; \
69 /* Removed -Tlatin1. Assuming system nroff has suitable default */ \
70 G.nroff = "nroff -mandoc"; \
71 G.pager = ENABLE_LESS ? "less" : "more"; \
72 } while (0)
73
74 static int show_manpage(char *man_filename, int man, int level);
75
run_pipe(char * man_filename,int man,int level)76 static int run_pipe(char *man_filename, int man, int level)
77 {
78 char *cmd;
79
80 /* Prevent man page link loops */
81 if (level > 10)
82 return 0;
83
84 if (access(man_filename, R_OK) != 0)
85 return 0;
86
87 if (option_mask32 & OPT_w) {
88 puts(man_filename);
89 return 1;
90 }
91
92 if (man) { /* man page, not cat page */
93 /* Is this a link to another manpage? */
94 /* The link has the following on the first line: */
95 /* ".so another_man_page" */
96
97 struct stat sb;
98 char *line;
99 char *linkname, *p;
100
101 /* On my system:
102 * man1/genhostid.1.gz: 203 bytes - smallest real manpage
103 * man2/path_resolution.2.gz: 114 bytes - largest link
104 */
105 xstat(man_filename, &sb);
106 if (sb.st_size > 300) /* err on the safe side */
107 goto ordinary_manpage;
108
109 line = xmalloc_open_zipped_read_close(man_filename, NULL);
110 if (!line || !is_prefixed_with(line, ".so ")) {
111 free(line);
112 goto ordinary_manpage;
113 }
114 /* Example: man2/path_resolution.2.gz contains
115 * ".so man7/path_resolution.7\n<junk>"
116 */
117 *strchrnul(line, '\n') = '\0';
118 linkname = skip_whitespace(&line[4]);
119
120 /* If link has no slashes, we just replace man page name.
121 * If link has slashes (however many), we go back *once*.
122 * ".so zzz/ggg/page.3" does NOT go back two levels. */
123 p = strrchr(man_filename, '/');
124 if (!p)
125 goto ordinary_manpage;
126 *p = '\0';
127 if (strchr(linkname, '/')) {
128 p = strrchr(man_filename, '/');
129 if (!p)
130 goto ordinary_manpage;
131 *p = '\0';
132 }
133
134 /* Links do not have .gz extensions, even if manpage
135 * is compressed */
136 man_filename = xasprintf("%s/%s", man_filename, linkname);
137 free(line);
138 /* Note: we leak "new" man_filename string as well... */
139 if (show_manpage(man_filename, man, level + 1))
140 return 1;
141 /* else: show the link, it's better than nothing */
142 }
143
144 ordinary_manpage:
145 close(STDIN_FILENO);
146 open_zipped(man_filename, /*fail_if_not_compressed:*/ 0); /* guaranteed to use fd 0 (STDIN_FILENO) */
147 if (man) {
148 int w = get_terminal_width(-1);
149 if (w > 10)
150 w -= 2;
151 /* "2>&1" is added so that nroff errors are shown in pager too.
152 * Otherwise it may show just empty screen.
153 */
154 cmd = xasprintf("%s | %s -rLL=%un -rLT=%un 2>&1 | %s",
155 G.tbl, G.nroff, w, w,
156 G.pager);
157 } else {
158 cmd = xstrdup(G.pager);
159 }
160 system(cmd);
161 free(cmd);
162 return 1;
163 }
164
165 /* man_filename is of the form "/dir/dir/dir/name.s" */
show_manpage(char * man_filename,int man,int level)166 static int show_manpage(char *man_filename, int man, int level)
167 {
168 #if SEAMLESS_COMPRESSION
169 /* We leak this allocation... */
170 char *filename_with_zext = xasprintf("%s.lzma", man_filename);
171 char *ext = strrchr(filename_with_zext, '.') + 1;
172 #endif
173
174 #if ENABLE_FEATURE_SEAMLESS_LZMA
175 if (run_pipe(filename_with_zext, man, level))
176 return 1;
177 #endif
178 #if ENABLE_FEATURE_SEAMLESS_XZ
179 strcpy(ext, "xz");
180 if (run_pipe(filename_with_zext, man, level))
181 return 1;
182 #endif
183 #if ENABLE_FEATURE_SEAMLESS_BZ2
184 strcpy(ext, "bz2");
185 if (run_pipe(filename_with_zext, man, level))
186 return 1;
187 #endif
188 #if ENABLE_FEATURE_SEAMLESS_GZ
189 strcpy(ext, "gz");
190 if (run_pipe(filename_with_zext, man, level))
191 return 1;
192 #endif
193
194 return run_pipe(man_filename, man, level);
195 }
196
add_MANPATH(char ** man_path_list,int * count_mp,char * path)197 static char **add_MANPATH(char **man_path_list, int *count_mp, char *path)
198 {
199 if (path) while (*path) {
200 char *next_path;
201 char **path_element;
202
203 next_path = strchr(path, ':');
204 if (next_path) {
205 if (next_path == path) /* "::"? */
206 goto next;
207 *next_path = '\0';
208 }
209 /* Do we already have path? */
210 path_element = man_path_list;
211 if (path_element) while (*path_element) {
212 if (strcmp(*path_element, path) == 0) {
213 goto skip;
214 }
215 path_element++;
216 }
217 man_path_list = xrealloc_vector(man_path_list, 4, *count_mp);
218 man_path_list[*count_mp] = xstrdup(path);
219 (*count_mp)++;
220 /* man_path_list is NULL terminated */
221 /* man_path_list[*count_mp] = NULL; - xrealloc_vector did it */
222 skip:
223 if (!next_path)
224 break;
225 /* "path" may be a result of getenv(), be nice and don't mangle it */
226 *next_path = ':';
227 next:
228 path = next_path + 1;
229 }
230 return man_path_list;
231 }
232
if_redefined(const char * var,const char * key,const char * line)233 static const char *if_redefined(const char *var, const char *key, const char *line)
234 {
235 if (!is_prefixed_with(line, key))
236 return var;
237 line += strlen(key);
238 if (!isspace(line[0]))
239 return var;
240 return xstrdup(skip_whitespace(line));
241 }
242
is_section_name(const char * sections,const char * str)243 static int is_section_name(const char *sections, const char *str)
244 {
245 const char *s = strstr(sections, str);
246 if (s) {
247 int l = strlen(str);
248 return (s[l] == ':' || s[l] == '\0');
249 }
250 return 0;
251 }
252
253 int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
man_main(int argc UNUSED_PARAM,char ** argv)254 int man_main(int argc UNUSED_PARAM, char **argv)
255 {
256 parser_t *parser;
257 char *conf_sec_list;
258 char *sec_list;
259 char **man_path_list;
260 int count_mp;
261 int opt, not_found;
262 char *token[2];
263
264 INIT_G();
265
266 opt = getopt32(argv, "^+" "aw" "\0" "-1"/*at least one arg*/);
267 argv += optind;
268
269 conf_sec_list = xstrdup("0p:1:1p:2:3:3p:4:5:6:7:8:9");
270
271 count_mp = 0;
272 man_path_list = add_MANPATH(NULL, &count_mp,
273 getenv("MANDATORY_MANPATH"+10) /* "MANPATH" */
274 );
275 /* Parse man.conf[ig] or man_db.conf */
276 /* man version 1.6f uses man.config */
277 /* man-db implementation of man uses man_db.conf */
278 parser = config_open2("/etc/man.config", fopen_for_read);
279 if (!parser)
280 parser = config_open2("/etc/man.conf", fopen_for_read);
281 if (!parser)
282 parser = config_open2("/etc/man_db.conf", fopen_for_read);
283
284 while (config_read(parser, token, 2, 0, "# \t", PARSE_NORMAL)) {
285 if (!token[1])
286 continue;
287 if (strcmp("DEFINE", token[0]) == 0) {
288 G.col = if_redefined(G.col , "col", token[1]);
289 G.tbl = if_redefined(G.tbl , "tbl", token[1]);
290 G.nroff = if_redefined(G.nroff, "nroff", token[1]);
291 G.pager = if_redefined(G.pager, "pager", token[1]);
292 } else
293 if (strcmp("MANDATORY_MANPATH"+10, token[0]) == 0 /* "MANPATH"? */
294 || strcmp("MANDATORY_MANPATH", token[0]) == 0
295 ) {
296 man_path_list = add_MANPATH(man_path_list, &count_mp, token[1]);
297 }
298 if (strcmp("MANSECT", token[0]) == 0) {
299 free(conf_sec_list);
300 conf_sec_list = xstrdup(token[1]);
301 }
302 }
303 config_close(parser);
304
305 if (!man_path_list) {
306 static const char *const mpl[] = { "/usr/man", "/usr/share/man", NULL };
307 man_path_list = (char**)mpl;
308 /*count_mp = 2; - not used below anyway */
309 }
310
311 {
312 /* environment overrides setting from man.config */
313 char *env_pager = getenv("MANPAGER");
314 if (!env_pager)
315 env_pager = getenv("PAGER");
316 if (env_pager)
317 G.pager = env_pager;
318 }
319
320 if (!isatty(STDOUT_FILENO)) {
321 putenv((char*)"GROFF_NO_SGR=1");
322 G.pager = xasprintf("%s -b -p -x", G.col);
323 }
324
325 /* is 1st ARG a SECTION? */
326 sec_list = conf_sec_list;
327 if (is_section_name(conf_sec_list, *argv) && argv[1]) {
328 /* yes */
329 sec_list = *argv++;
330 }
331
332 not_found = 0;
333 do { /* for each argv[] */
334 const char *cur_path;
335 int cur_mp;
336 int found = 0;
337
338 if (strchr(*argv, '/')) {
339 found = show_manpage(*argv, /*man:*/ 1, 0);
340 goto check_found;
341 }
342
343 /* for each MANPATH */
344 cur_mp = 0;
345 while ((cur_path = man_path_list[cur_mp++]) != NULL) {
346 const char *cur_sect = sec_list;
347
348 /* is MANPAGE of the form NAME.SECTION? */
349 char *sect_ext = strrchr(*argv, '.');
350 if (sect_ext && is_section_name(conf_sec_list, sect_ext + 1)) {
351 *sect_ext = '\0';
352 cur_sect = sect_ext + 1;
353 }
354
355 do { /* for each SECTION in cur_sect */
356 char *next_sect = strchrnul(cur_sect, ':');
357 int sect_len = next_sect - cur_sect;
358 char *man_filename;
359 int cat0man1 = 0;
360
361 /* Search for cat, then man page */
362 while (cat0man1 < 2) {
363 int found_here;
364 man_filename = xasprintf("%s/%s%.*s/%s.%.*s",
365 cur_path,
366 "cat\0man" + (cat0man1 * 4),
367 sect_len, cur_sect,
368 *argv,
369 sect_len, cur_sect);
370 found_here = show_manpage(man_filename, cat0man1, 0);
371 found |= found_here;
372 cat0man1 += found_here + 1;
373 free(man_filename);
374 }
375
376 if (found && !(opt & OPT_a))
377 goto next_arg;
378 cur_sect = next_sect;
379 while (*cur_sect == ':')
380 cur_sect++;
381 } while (*cur_sect);
382
383 if (sect_ext) *sect_ext = '.';
384 }
385 check_found:
386 if (!found) {
387 bb_error_msg("no manual entry for '%s'", *argv);
388 not_found = 1;
389 }
390 next_arg:
391 argv++;
392 } while (*argv);
393
394 return not_found;
395 }
396