dc: fix "dc does_not_exist" SEGVing
[oweals/busybox.git] / miscutils / man.c
index 51baceb165a25b5a2e79a35e68efdfdc6f4aeae5..ba6bb4c01f6df7a2570a37fbab53594cd3e63921 100644 (file)
@@ -2,6 +2,15 @@
  * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
  * Licensed under GPLv2, see file LICENSE in this source tree.
  */
+//config:config MAN
+//config:      bool "man (27 kb)"
+//config:      default y
+//config:      help
+//config:      Format and display manual pages.
+
+//applet:IF_MAN(APPLET(man, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_MAN) += man.o
 
 //usage:#define man_trivial_usage
 //usage:       "[-aw] [MANPAGE]..."
@@ -9,8 +18,11 @@
 //usage:       "Format and display manual page\n"
 //usage:     "\n       -a      Display all pages"
 //usage:     "\n       -w      Show page locations"
+//usage:     "\n"
+//usage:     "\n$COLUMNS overrides output width"
 
 #include "libbb.h"
+#include "common_bufsiz.h"
 
 enum {
        OPT_a = 1, /* all */
@@ -18,7 +30,6 @@ enum {
 };
 
 /* This is what I see on my desktop system being executed:
-
 (
 echo ".ll 12.4i"
 echo ".nr LL 12.4i"
@@ -28,11 +39,41 @@ echo ".\\\""
 echo ".pl \n(nlu+10"
 ) | gtbl | nroff -Tlatin1 -mandoc | less
 
-*/
+Some systems use -Tascii.
+
+On another system I see this:
 
-static int show_manpage(const char *pager, char *man_filename, int man, int level);
+... | tbl | nroff -mandoc -rLL=<NNN>n -rLT=<NNN>n -Tutf8 | less
 
-static int run_pipe(const char *pager, char *man_filename, int man, int level)
+where <NNN> is screen width minus 5.
+Replacing "DEFINE nroff nroff -mandoc" in /etc/man_db.conf
+changes "nroff -mandoc" part; -rLL=<NNN>n, -rLT=<NNN>n and -Tutf8 parts are
+appended to the user-specified command.
+
+Redirecting to a pipe or file sets GROFF_NO_SGR=1 to prevent color escapes,
+and uses "col -b -p -x" instead of pager, this filters out backspace
+and underscore tricks.
+*/
+
+struct globals {
+       const char *col;
+       const char *tbl;
+       const char *nroff;
+       const char *pager;
+} FIX_ALIASING;
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() do { \
+       setup_common_bufsiz(); \
+       G.col = "col"; \
+       G.tbl = "tbl"; \
+       /* Removed -Tlatin1. Assuming system nroff has suitable default */ \
+       G.nroff = "nroff -mandoc"; \
+       G.pager = ENABLE_LESS ? "less" : "more"; \
+} while (0)
+
+static int show_manpage(char *man_filename, int man, int level);
+
+static int run_pipe(char *man_filename, int man, int level)
 {
        char *cmd;
 
@@ -66,7 +107,7 @@ static int run_pipe(const char *pager, char *man_filename, int man, int level)
                        goto ordinary_manpage;
 
                line = xmalloc_open_zipped_read_close(man_filename, NULL);
-               if (!line || strncmp(line, ".so ", 4) != 0) {
+               if (!line || !is_prefixed_with(line, ".so ")) {
                        free(line);
                        goto ordinary_manpage;
                }
@@ -95,27 +136,34 @@ static int run_pipe(const char *pager, char *man_filename, int man, int level)
                man_filename = xasprintf("%s/%s", man_filename, linkname);
                free(line);
                /* Note: we leak "new" man_filename string as well... */
-               if (show_manpage(pager, man_filename, man, level + 1))
+               if (show_manpage(man_filename, man, level + 1))
                        return 1;
                /* else: show the link, it's better than nothing */
        }
 
  ordinary_manpage:
        close(STDIN_FILENO);
-       open_zipped(man_filename); /* guaranteed to use fd 0 (STDIN_FILENO) */
-       /* "2>&1" is added so that nroff errors are shown in pager too.
-        * Otherwise it may show just empty screen */
-       cmd = xasprintf(
-               man ? "gtbl | nroff -Tlatin1 -mandoc 2>&1 | %s"
-                   : "%s",
-               pager);
+       open_zipped(man_filename, /*fail_if_not_compressed:*/ 0); /* guaranteed to use fd 0 (STDIN_FILENO) */
+       if (man) {
+               int w = get_terminal_width(-1);
+               if (w > 10)
+                       w -= 2;
+               /* "2>&1" is added so that nroff errors are shown in pager too.
+                * Otherwise it may show just empty screen.
+                */
+               cmd = xasprintf("%s | %s -rLL=%un -rLT=%un 2>&1 | %s",
+                               G.tbl, G.nroff, w, w,
+                               G.pager);
+       } else {
+               cmd = xstrdup(G.pager);
+       }
        system(cmd);
        free(cmd);
        return 1;
 }
 
 /* man_filename is of the form "/dir/dir/dir/name.s" */
-static int show_manpage(const char *pager, char *man_filename, int man, int level)
+static int show_manpage(char *man_filename, int man, int level)
 {
 #if SEAMLESS_COMPRESSION
        /* We leak this allocation... */
@@ -124,53 +172,105 @@ static int show_manpage(const char *pager, char *man_filename, int man, int leve
 #endif
 
 #if ENABLE_FEATURE_SEAMLESS_LZMA
-       if (run_pipe(pager, filename_with_zext, man, level))
+       if (run_pipe(filename_with_zext, man, level))
                return 1;
 #endif
 #if ENABLE_FEATURE_SEAMLESS_XZ
        strcpy(ext, "xz");
-       if (run_pipe(pager, filename_with_zext, man, level))
+       if (run_pipe(filename_with_zext, man, level))
                return 1;
 #endif
 #if ENABLE_FEATURE_SEAMLESS_BZ2
        strcpy(ext, "bz2");
-       if (run_pipe(pager, filename_with_zext, man, level))
+       if (run_pipe(filename_with_zext, man, level))
                return 1;
 #endif
 #if ENABLE_FEATURE_SEAMLESS_GZ
        strcpy(ext, "gz");
-       if (run_pipe(pager, filename_with_zext, man, level))
+       if (run_pipe(filename_with_zext, man, level))
                return 1;
 #endif
 
-       return run_pipe(pager, man_filename, man, level);
+       return run_pipe(man_filename, man, level);
+}
+
+static char **add_MANPATH(char **man_path_list, int *count_mp, char *path)
+{
+       if (path) while (*path) {
+               char *next_path;
+               char **path_element;
+
+               next_path = strchr(path, ':');
+               if (next_path) {
+                       if (next_path == path) /* "::"? */
+                               goto next;
+                       *next_path = '\0';
+               }
+               /* Do we already have path? */
+               path_element = man_path_list;
+               if (path_element) while (*path_element) {
+                       if (strcmp(*path_element, path) == 0)
+                               goto skip;
+                       path_element++;
+               }
+               man_path_list = xrealloc_vector(man_path_list, 4, *count_mp);
+               man_path_list[*count_mp] = xstrdup(path);
+               (*count_mp)++;
+               /* man_path_list is NULL terminated */
+               /* man_path_list[*count_mp] = NULL; - xrealloc_vector did it */
+ skip:
+               if (!next_path)
+                       break;
+               /* "path" may be a result of getenv(), be nice and don't mangle it */
+               *next_path = ':';
+ next:
+               path = next_path + 1;
+       }
+       return man_path_list;
+}
+
+static const char *if_redefined(const char *var, const char *key, const char *line)
+{
+       if (!is_prefixed_with(line, key))
+               return var;
+       line += strlen(key);
+       if (!isspace(line[0]))
+               return var;
+       return xstrdup(skip_whitespace(line));
 }
 
 int man_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int man_main(int argc UNUSED_PARAM, char **argv)
 {
        parser_t *parser;
-       const char *pager = ENABLE_LESS ? "less" : "more";
-       char **man_path_list;
        char *sec_list;
        char *cur_path, *cur_sect;
-       int count_mp, cur_mp;
+       char **man_path_list;
+       int count_mp;
+       int cur_mp;
        int opt, not_found;
        char *token[2];
 
-       opt_complementary = "-1"; /* at least one argument */
-       opt = getopt32(argv, "+aw");
+       INIT_G();
+
+       opt = getopt32(argv, "^+" "aw" "\0" "-1"/*at least one arg*/);
        argv += optind;
 
        sec_list = xstrdup("0p:1:1p:2:3:3p:4:5:6:7:8:9");
-       /* Last valid man_path_list[] is [0x10] */
+
        count_mp = 0;
-       man_path_list = xzalloc(0x11 * sizeof(man_path_list[0]));
-       man_path_list[0] = getenv("MANPATH");
-       if (!man_path_list[0]) /* default, may be overridden by /etc/man.conf */
+       man_path_list = add_MANPATH(NULL, &count_mp,
+                       getenv("MANDATORY_MANPATH"+10) /* "MANPATH" */
+       );
+       if (!man_path_list) {
+               /* default, may be overridden by /etc/man.conf */
+               man_path_list = xzalloc(2 * sizeof(man_path_list[0]));
                man_path_list[0] = (char*)"/usr/man";
-       else
-               count_mp++;
+               /* count_mp stays 0.
+                * Thus, man.conf will overwrite man_path_list[0]
+                * if a path is defined there.
+                */
+       }
 
        /* Parse man.conf[ig] or man_db.conf */
        /* man version 1.6f uses man.config */
@@ -185,42 +285,15 @@ int man_main(int argc UNUSED_PARAM, char **argv)
                if (!token[1])
                        continue;
                if (strcmp("DEFINE", token[0]) == 0) {
-                       if (strncmp("pager", token[1], 5) == 0) {
-                               pager = xstrdup(skip_whitespace(token[1]) + 5);
-                       }
+                       G.col   = if_redefined(G.tbl  , "col",   token[1]);
+                       G.tbl   = if_redefined(G.tbl  , "tbl",   token[1]);
+                       G.nroff = if_redefined(G.nroff, "nroff", token[1]);
+                       G.pager = if_redefined(G.pager, "pager", token[1]);
                } else
                if (strcmp("MANDATORY_MANPATH"+10, token[0]) == 0 /* "MANPATH"? */
                 || strcmp("MANDATORY_MANPATH", token[0]) == 0
                ) {
-                       char *path = token[1];
-                       while (*path) {
-                               char *next_path;
-                               char **path_element;
-
-                               next_path = strchr(path, ':');
-                               if (next_path) {
-                                       *next_path = '\0';
-                                       if (next_path++ == path) /* "::"? */
-                                               goto next;
-                               }
-                               /* Do we already have path? */
-                               path_element = man_path_list;
-                               while (*path_element) {
-                                       if (strcmp(*path_element, path) == 0)
-                                               goto skip;
-                                       path_element++;
-                               }
-                               man_path_list = xrealloc_vector(man_path_list, 4, count_mp);
-                               man_path_list[count_mp] = xstrdup(path);
-                               count_mp++;
-                               /* man_path_list is NULL terminated */
-                               /*man_path_list[count_mp] = NULL; - xrealloc_vector did it */
- skip:
-                               if (!next_path)
-                                       break;
- next:
-                               path = next_path;
-                       }
+                       man_path_list = add_MANPATH(man_path_list, &count_mp, token[1]);
                }
                if (strcmp("MANSECT", token[0]) == 0) {
                        free(sec_list);
@@ -235,7 +308,12 @@ int man_main(int argc UNUSED_PARAM, char **argv)
                if (!env_pager)
                        env_pager = getenv("PAGER");
                if (env_pager)
-                       pager = env_pager;
+                       G.pager = env_pager;
+       }
+
+       if (!isatty(STDOUT_FILENO)) {
+               putenv((char*)"GROFF_NO_SGR=1");
+               G.pager = xasprintf("%s -b -p -x", G.col);
        }
 
        not_found = 0;
@@ -244,7 +322,7 @@ int man_main(int argc UNUSED_PARAM, char **argv)
                cur_mp = 0;
 
                if (strchr(*argv, '/')) {
-                       found = show_manpage(pager, *argv, /*man:*/ 1, 0);
+                       found = show_manpage(*argv, /*man:*/ 1, 0);
                        goto check_found;
                }
                while ((cur_path = man_path_list[cur_mp++]) != NULL) {
@@ -265,7 +343,7 @@ int man_main(int argc UNUSED_PARAM, char **argv)
                                                        sect_len, cur_sect,
                                                        *argv,
                                                        sect_len, cur_sect);
-                                       found_here = show_manpage(pager, man_filename, cat0man1, 0);
+                                       found_here = show_manpage(man_filename, cat0man1, 0);
                                        found |= found_here;
                                        cat0man1 += found_here + 1;
                                        free(man_filename);