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path: root/miscutils/man.c (plain)
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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"
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-$(CONFIG_MAN) += man.o
14
15//usage:#define man_trivial_usage
16//usage: "[-aw] [MANPAGE]..."
17//usage:#define man_full_usage "\n\n"
18//usage: "Format and display manual page\n"
19//usage: "\n -a Display all pages"
20//usage: "\n -w Show page locations"
21//usage: "\n"
22//usage: "\n$COLUMNS overrides output width"
23
24#include "libbb.h"
25#include "common_bufsiz.h"
26
27enum {
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(
34echo ".ll 12.4i"
35echo ".nr LL 12.4i"
36echo ".pl 1100i"
37gunzip -c '/usr/man/man1/bzip2.1.gz'
38echo ".\\\""
39echo ".pl \n(nlu+10"
40) | gtbl | nroff -Tlatin1 -mandoc | less
41
42Some systems use -Tascii.
43
44On another system I see this:
45
46... | tbl | nroff -mandoc -rLL=<NNN>n -rLT=<NNN>n -Tutf8 | less
47
48where <NNN> is screen width minus 5.
49Replacing "DEFINE nroff nroff -mandoc" in /etc/man_db.conf
50changes "nroff -mandoc" part; -rLL=<NNN>n, -rLT=<NNN>n and -Tutf8 parts are
51appended to the user-specified command.
52
53Redirecting to a pipe or file sets GROFF_NO_SGR=1 to prevent color escapes,
54and uses "col -b -p -x" instead of pager, this filters out backspace
55and underscore tricks.
56*/
57
58struct 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
74static int show_manpage(char *man_filename, int man, int level);
75
76static 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" */
166static 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
197static 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 path_element++;
215 }
216 man_path_list = xrealloc_vector(man_path_list, 4, *count_mp);
217 man_path_list[*count_mp] = xstrdup(path);
218 (*count_mp)++;
219 /* man_path_list is NULL terminated */
220 /* man_path_list[*count_mp] = NULL; - xrealloc_vector did it */
221 skip:
222 if (!next_path)
223 break;
224 /* "path" may be a result of getenv(), be nice and don't mangle it */
225 *next_path = ':';
226 next:
227 path = next_path + 1;
228 }
229 return man_path_list;
230}
231
232static const char *if_redefined(const char *var, const char *key, const char *line)
233{
234 if (!is_prefixed_with(line, key))
235 return var;
236 line += strlen(key);
237 if (!isspace(line[0]))
238 return var;
239 return xstrdup(skip_whitespace(line));
240}
241
242int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
243int man_main(int argc UNUSED_PARAM, char **argv)
244{
245 parser_t *parser;
246 char *sec_list;
247 char *cur_path, *cur_sect;
248 char **man_path_list;
249 int count_mp;
250 int cur_mp;
251 int opt, not_found;
252 char *token[2];
253
254 INIT_G();
255
256 opt_complementary = "-1"; /* at least one argument */
257 opt = getopt32(argv, "+aw");
258 argv += optind;
259
260 sec_list = xstrdup("0p:1:1p:2:3:3p:4:5:6:7:8:9");
261
262 count_mp = 0;
263 man_path_list = add_MANPATH(NULL, &count_mp,
264 getenv("MANDATORY_MANPATH"+10) /* "MANPATH" */
265 );
266 if (!man_path_list) {
267 /* default, may be overridden by /etc/man.conf */
268 man_path_list = xzalloc(2 * sizeof(man_path_list[0]));
269 man_path_list[0] = (char*)"/usr/man";
270 /* count_mp stays 0.
271 * Thus, man.conf will overwrite man_path_list[0]
272 * if a path is defined there.
273 */
274 }
275
276 /* Parse man.conf[ig] or man_db.conf */
277 /* man version 1.6f uses man.config */
278 /* man-db implementation of man uses man_db.conf */
279 parser = config_open2("/etc/man.config", fopen_for_read);
280 if (!parser)
281 parser = config_open2("/etc/man.conf", fopen_for_read);
282 if (!parser)
283 parser = config_open2("/etc/man_db.conf", fopen_for_read);
284
285 while (config_read(parser, token, 2, 0, "# \t", PARSE_NORMAL)) {
286 if (!token[1])
287 continue;
288 if (strcmp("DEFINE", token[0]) == 0) {
289 G.col = if_redefined(G.tbl , "col", token[1]);
290 G.tbl = if_redefined(G.tbl , "tbl", token[1]);
291 G.nroff = if_redefined(G.nroff, "nroff", token[1]);
292 G.pager = if_redefined(G.pager, "pager", token[1]);
293 } else
294 if (strcmp("MANDATORY_MANPATH"+10, token[0]) == 0 /* "MANPATH"? */
295 || strcmp("MANDATORY_MANPATH", token[0]) == 0
296 ) {
297 man_path_list = add_MANPATH(man_path_list, &count_mp, token[1]);
298 }
299 if (strcmp("MANSECT", token[0]) == 0) {
300 free(sec_list);
301 sec_list = xstrdup(token[1]);
302 }
303 }
304 config_close(parser);
305
306 {
307 /* environment overrides setting from man.config */
308 char *env_pager = getenv("MANPAGER");
309 if (!env_pager)
310 env_pager = getenv("PAGER");
311 if (env_pager)
312 G.pager = env_pager;
313 }
314
315 if (!isatty(STDOUT_FILENO)) {
316 putenv((char*)"GROFF_NO_SGR=1");
317 G.pager = xasprintf("%s -b -p -x", G.col);
318 }
319
320 not_found = 0;
321 do { /* for each argv[] */
322 int found = 0;
323 cur_mp = 0;
324
325 if (strchr(*argv, '/')) {
326 found = show_manpage(*argv, /*man:*/ 1, 0);
327 goto check_found;
328 }
329 while ((cur_path = man_path_list[cur_mp++]) != NULL) {
330 /* for each MANPATH */
331 cur_sect = sec_list;
332 do { /* for each section */
333 char *next_sect = strchrnul(cur_sect, ':');
334 int sect_len = next_sect - cur_sect;
335 char *man_filename;
336 int cat0man1 = 0;
337
338 /* Search for cat, then man page */
339 while (cat0man1 < 2) {
340 int found_here;
341 man_filename = xasprintf("%s/%s%.*s/%s.%.*s",
342 cur_path,
343 "cat\0man" + (cat0man1 * 4),
344 sect_len, cur_sect,
345 *argv,
346 sect_len, cur_sect);
347 found_here = show_manpage(man_filename, cat0man1, 0);
348 found |= found_here;
349 cat0man1 += found_here + 1;
350 free(man_filename);
351 }
352
353 if (found && !(opt & OPT_a))
354 goto next_arg;
355 cur_sect = next_sect;
356 while (*cur_sect == ':')
357 cur_sect++;
358 } while (*cur_sect);
359 }
360 check_found:
361 if (!found) {
362 bb_error_msg("no manual entry for '%s'", *argv);
363 not_found = 1;
364 }
365 next_arg:
366 argv++;
367 } while (*argv);
368
369 return not_found;
370}
371
generated by cgit at 2024-05-16 02:39:08 (GMT)