busybox/miscutils/man.c

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/* 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:
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(
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)
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{
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);
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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)
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{
int len;
if (run_pipe("bunzip2 -c", pager, man_filename, man))
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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))
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return 1;
man_filename[len - 3] = '\0'; /* ".gz" -> "" */
if (run_pipe(STR_cat, pager, man_filename, man))
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return 1;
return 0;
}
int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int man_main(int argc UNUSED_PARAM, char **argv)
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{
FILE *cf;
const char *pager;
char **man_path_list;
char *sec_list;
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char *cur_path, *cur_sect;
char *line, *value;
int count_mp, cur_mp;
int opt, not_found;
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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++;
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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;
man_path_list = xrealloc_vector(man_path_list, 4, count_mp);
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}
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;
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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))
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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;
}
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next_arg:
argv++;
} while (*argv);
return not_found;
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}