man: new applet. ~600 bytes.

include/applets.h

@@ -237,6 +237,7 @@ USE_LSATTR(APPLET(lsattr, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_LSMOD(APPLET(lsmod, _BB_DIR_SBIN, _BB_SUID_NEVER))
 USE_UNLZMA(APPLET_ODDNAME(lzmacat, unlzma, _BB_DIR_USR_BIN, _BB_SUID_NEVER, lzmacat))
 USE_MAKEDEVS(APPLET(makedevs, _BB_DIR_SBIN, _BB_SUID_NEVER))
+USE_MAN(APPLET(man, _BB_DIR_SBIN, _BB_SUID_NEVER)) 
 USE_MATCHPATHCON(APPLET(matchpathcon, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))
 USE_MD5SUM(APPLET_ODDNAME(md5sum, md5_sha1_sum, _BB_DIR_USR_BIN, _BB_SUID_NEVER, md5sum))
 USE_MDEV(APPLET(mdev, _BB_DIR_SBIN, _BB_SUID_NEVER))

include/usage.h

@@ -2300,6 +2300,14 @@
        "/dev/hda[0-15]\n"
 #endif
 
+#define man_trivial_usage \
+       "[OPTION]... [MANPAGE]..."
+#define man_full_usage \
+       "Format and display manual page\n" \
+     "\nOptions:" \
+     "\n	-a      Display all pages" \
+     "\n	-w	Show page locations" \
+
 #define matchpathcon_trivial_usage \
        "[-n] [-N] [-f file_contexts_file] [-p prefix] [-V]"
 #define matchpathcon_full_usage \

miscutils/Config.in

@@ -372,6 +372,12 @@ config FEATURE_MAKEDEVS_TABLE
 
 endchoice
 
+config MAN
+	bool "man"
+	default n
+	help
+	  Format and display manual pages.
+
 config MICROCOM
 	bool "microcom"
 	default n

miscutils/Kbuild

@@ -19,6 +19,7 @@ lib-$(CONFIG_HDPARM)      += hdparm.o
 lib-$(CONFIG_LAST)        += last.o
 lib-$(CONFIG_LESS)        += less.o
 lib-$(CONFIG_MAKEDEVS)    += makedevs.o
+lib-$(CONFIG_MAN)         += man.o
 lib-$(CONFIG_MICROCOM)    += microcom.o
 lib-$(CONFIG_MOUNTPOINT)  += mountpoint.o
 lib-$(CONFIG_MT)          += mt.o

miscutils/man.c

@@ -0,0 +1,151 @@
+/* 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 deing 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
+
+*/
+
+static int run_pipe(const char *unpacker, const char *pager, char *man_filename)
+{
+	char *cmd;
+
+	if (access(man_filename, R_OK) != 0)
+		return 0;
+
+	if (option_mask32 & OPT_w) {
+		puts(man_filename);
+		return 1;
+	}
+
+	cmd = xasprintf("%s '%s' | gtbl | nroff -Tlatin1 -mandoc | %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 len;
+
+	if (run_pipe("bunzip2 -c", pager, man_filename))
+		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))
+		return 1;
+
+	man_filename[len - 3] = '\0'; /* ".gz" -> "" */
+	if (run_pipe("cat", pager, man_filename))
+		return 1;
+
+	return 0;
+}
+
+int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int man_main(int argc ATTRIBUTE_UNUSED, char **argv)
+{
+	FILE *cf;
+	const char *pager;
+	char *man_path, *sec_list;
+	char *cur_path, *cur_sect;
+	char *line, *value;
+	int opt;
+
+	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");
+	man_path = xstrdup(getenv("MANPATH"));
+	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) {
+					free(man_path);
+						man_path = xstrdup(value);
+				}
+				if (strcmp("MANSECT", line) == 0) {
+					free(sec_list);
+					sec_list = xstrdup(value);
+				}
+			}
+			free(line);
+		}
+		fclose(cf);
+	}
+
+	do { /* for each argv[] */
+		cur_path = man_path;
+		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 = xasprintf("%.*s/man%.*s/%s.%.*s" ".bz2",
+							path_len, cur_path,
+			        			sect_len, cur_sect,
+			        			*argv,
+							sect_len, cur_sect);
+				if (show_manpage(pager, man_filename)) {
+					if (!(opt & OPT_a)) {
+						goto next_arg;
+					}
+				}
+				free(man_filename);
+
+				cur_sect = next_sect;
+				while (*cur_sect == ':')
+					cur_sect++;
+			} while (*cur_sect);
+
+			cur_path = next_path;
+			while (*cur_path == ':')
+				cur_path++;
+		} while (*cur_path);
+ next_arg:
+		argv++;
+	} while (*argv);
+
+	return EXIT_SUCCESS;
+}