summaryrefslogtreecommitdiffhomepage
path: root/miscutils/man.c
blob: 3685be7b66126537c5870dcd023f5f688f71123e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
/* mini man implementation for busybox
 * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
 * Licensed under GPLv2, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

enum {
	OPT_a = 1, /* all */
	OPT_w = 2, /* print path */
};

/* This is what I see on my desktop system being executed:

(
echo ".ll 12.4i"
echo ".nr LL 12.4i"
echo ".pl 1100i"
gunzip -c '/usr/man/man1/bzip2.1.gz'
echo ".\\\""
echo ".pl \n(nlu+10"
) | gtbl | nroff -Tlatin1 -mandoc | less

*/

/* Trick gcc to reuse "cat" string. */
#define STR_catNULmanNUL "cat\0man"
#define STR_cat          "cat\0man"

static int run_pipe(const char *unpacker, const char *pager, char *man_filename, int man)
{
	char *cmd;

	if (access(man_filename, R_OK) != 0)
		return 0;

	if (option_mask32 & OPT_w) {
		puts(man_filename);
		return 1;
	}

	/* "2>&1" is added so that nroff errors are shown in pager too.
	 * Otherwise it may show just empty screen */
	cmd = xasprintf(
		man ? "%s '%s' | gtbl | nroff -Tlatin1 -mandoc 2>&1 | %s"
		    : "%s '%s' | %s",
		unpacker, man_filename, pager);
	system(cmd);
	free(cmd);
	return 1;
}

/* man_filename is of the form "/dir/dir/dir/name.s.bz2" */
static int show_manpage(const char *pager, char *man_filename, int man)
{
	int len;

	if (run_pipe("bunzip2 -c", pager, man_filename, man))
		return 1;

	len = strlen(man_filename) - 1;

	man_filename[len] = '\0'; /* ".bz2" -> ".gz" */
	man_filename[len - 2] = 'g';
	if (run_pipe("gunzip -c", pager, man_filename, man))
		return 1;

	man_filename[len - 3] = '\0'; /* ".gz" -> "" */
	if (run_pipe(STR_cat, pager, man_filename, man))
		return 1;

	return 0;
}

int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int man_main(int argc UNUSED_PARAM, char **argv)
{
	FILE *cf;
	const char *pager;
	char **man_path_list;
	char *sec_list;
	char *cur_path, *cur_sect;
	char *line, *value;
	int count_mp, cur_mp;
	int opt, not_found;

	opt_complementary = "-1"; /* at least one argument */
	opt = getopt32(argv, "+aw");
	argv += optind;

	sec_list = xstrdup("1:2:3:4:5:6:7:8:9");
	/* Last valid man_path_list[] is [0x10] */
	man_path_list = xzalloc(0x11 * sizeof(man_path_list[0]));
	count_mp = 0;
	man_path_list[0] = xstrdup(getenv("MANPATH"));
	if (man_path_list[0])
		count_mp++;
	pager = getenv("MANPAGER");
	if (!pager) {
		pager = getenv("PAGER");
		if (!pager)
			pager = "more";
	}

	/* Parse man.conf */
	cf = fopen_or_warn("/etc/man.conf", "r");
	if (cf) {
		/* go through man configuration file and search relevant paths, sections */
		while ((line = xmalloc_fgetline(cf)) != NULL) {
			trim(line); /* remove whitespace at the beginning/end */
			if (isspace(line[7])) {
				line[7] = '\0';
				value = skip_whitespace(&line[8]);
				*skip_non_whitespace(value) = '\0';
				if (strcmp("MANPATH", line) == 0) {
					man_path_list[count_mp] = xstrdup(value);
					count_mp++;
					/* man_path_list is NULL terminated */
					man_path_list[count_mp] = NULL;
					if (!(count_mp & 0xf)) { /* 0x10, 0x20 etc */
						/* so that last valid man_path_list[] is [count_mp + 0x10] */
						man_path_list = xrealloc(man_path_list,
							(count_mp + 0x11) * sizeof(man_path_list[0]));
					}
				}
				if (strcmp("MANSECT", line) == 0) {
					free(sec_list);
					sec_list = xstrdup(value);
				}
			}
			free(line);
		}
		fclose(cf);
	}

// TODO: my man3/getpwuid.3.gz contains just one line:
// .so man3/getpwnam.3
// (and I _dont_ have man3/getpwnam.3, I have man3/getpwnam.3.gz)
// need to support this...

	not_found = 0;
	do { /* for each argv[] */
		int found = 0;
		cur_mp = 0;
		while ((cur_path = man_path_list[cur_mp++]) != NULL) {
			/* for each MANPATH */
			do { /* for each MANPATH item */
				char *next_path = strchrnul(cur_path, ':');
				int path_len = next_path - cur_path;
				cur_sect = sec_list;
				do { /* for each section */
					char *next_sect = strchrnul(cur_sect, ':');
					int sect_len = next_sect - cur_sect;
					char *man_filename;
					int cat0man1 = 0;

					/* Search for cat, then man page */
					while (cat0man1 < 2) {
						int found_here;
						man_filename = xasprintf("%.*s/%s%.*s/%s.%.*s" ".bz2",
								path_len, cur_path,
								STR_catNULmanNUL + cat0man1 * 4,
								sect_len, cur_sect,
								*argv,
								sect_len, cur_sect);
						found_here = show_manpage(pager, man_filename, cat0man1);
						found |= found_here;
						cat0man1 += found_here + 1;
						free(man_filename);
					}

					if (found && !(opt & OPT_a))
						goto next_arg;
					cur_sect = next_sect;
					while (*cur_sect == ':')
						cur_sect++;
				} while (*cur_sect);
				cur_path = next_path;
				while (*cur_path == ':')
					cur_path++;
			} while (*cur_path);
		}
		if (!found) {
			bb_error_msg("no manual entry for '%s'", *argv);
			not_found = 1;
		}
 next_arg:
		argv++;
	} while (*argv);

	return not_found;
}