contrib/tcsh-6/tw.help.c

   1 /* $Header: /p/tcsh/cvsroot/tcsh/tw.help.c,v 3.27 2006/08/24 20:56:31 christos Exp $ */
   2 /* tw.help.c: actually look up and print documentation on a file.
   3  *            Look down the path for an appropriate file, then print it.
   4  *            Note that the printing is NOT PAGED.  This is because the
   5  *            function is NOT meant to look at manual pages, it only does so
   6  *            if there is no .help file to look in.
   7  */
   8 /*-
   9  * Copyright (c) 1980, 1991 The Regents of the University of California.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36 #include "sh.h"
  37
  38 RCSID("$tcsh: tw.help.c,v 3.27 2006/08/24 20:56:31 christos Exp $")
  39
  40 #include "tw.h"
  41 #include "tc.h"
  42
  43
  44 static int f = -1;
  45 static  void             cleanf         (int);
  46 static  Char            *skipslist      (Char *);
  47 static  void             nextslist      (const Char *, Char *);
  48
  49 static const char *const h_ext[] = {
  50     ".help", ".1", ".8", ".6", "", NULL
  51 };
  52
  53 void
  54 do_help(const Char *command)
  55 {
  56     Char   *name, *cmd_p;
  57
  58     /* trim off the whitespace at the beginning */
  59     while (*command == ' ' || *command == '\t')
  60         command++;
  61
  62     /* copy the string to a safe place */
  63     name = Strsave(command);
  64     cleanup_push(name, xfree);
  65
  66     /* trim off the whitespace that may be at the end */
  67     for (cmd_p = name;
  68          *cmd_p != ' ' && *cmd_p != '\t' && *cmd_p != '\0'; cmd_p++)
  69         continue;
  70     *cmd_p = '\0';
  71
  72     /* if nothing left, return */
  73     if (*name == '\0') {
  74         cleanup_until(name);
  75         return;
  76     }
  77
  78     if (adrof1(STRhelpcommand, &aliases)) {     /* if we have an alias */
  79         jmp_buf_t osetexit;
  80         size_t omark;
  81
  82         getexit(osetexit);      /* make sure to come back here */
  83         omark = cleanup_push_mark();
  84         if (setexit() == 0)
  85             aliasrun(2, STRhelpcommand, name);  /* then use it. */
  86         cleanup_pop_mark(omark);
  87         resexit(osetexit);      /* and finish up */
  88     }
  89     else {                      /* else cat something to them */
  90         Char *thpath, *hpath;   /* The environment parameter */
  91         Char *curdir;           /* Current directory being looked at */
  92         struct Strbuf full = Strbuf_INIT;
  93
  94         /* got is, now "cat" the file based on the path $HPATH */
  95
  96         hpath = str2short(getenv(SEARCHLIST));
  97         if (hpath == NULL)
  98             hpath = str2short(DEFAULTLIST);
  99         thpath = hpath = Strsave(hpath);
 100         cleanup_push(thpath, xfree);
 101         curdir = xmalloc((Strlen(thpath) + 1) * sizeof (*curdir));
 102         cleanup_push(curdir, xfree);
 103         cleanup_push(&full, Strbuf_cleanup);
 104
 105         for (;;) {
 106             const char *const *sp;
 107             size_t ep;
 108
 109             if (!*hpath) {
 110                 xprintf(CGETS(29, 1, "No help file for %S\n"), name);
 111                 break;
 112             }
 113             nextslist(hpath, curdir);
 114             hpath = skipslist(hpath);
 115
 116             /*
 117              * now make the full path name - try first /bar/foo.help, then
 118              * /bar/foo.1, /bar/foo.8, then finally /bar/foo.6.  This is so
 119              * that you don't spit a binary at the tty when $HPATH == $PATH.
 120              */
 121             full.len = 0;
 122             Strbuf_append(&full, curdir);
 123             Strbuf_append(&full, STRslash);
 124             Strbuf_append(&full, name);
 125             ep = full.len;
 126             for (sp = h_ext; *sp; sp++) {
 127                 full.len = ep;
 128                 Strbuf_append(&full, str2short(*sp));
 129                 Strbuf_terminate(&full);
 130                 if ((f = xopen(short2str(full.s), O_RDONLY|O_LARGEFILE)) != -1)
 131                     break;
 132             }
 133             if (f != -1) {
 134                 unsigned char buf[512];
 135                 sigset_t oset, set;
 136                 struct sigaction osa, sa;
 137                 ssize_t len;
 138
 139                 /* so cat it to the terminal */
 140                 cleanup_push(&f, open_cleanup);
 141                 sa.sa_handler = cleanf;
 142                 sigemptyset(&sa.sa_mask);
 143                 sa.sa_flags = 0;
 144                 (void)sigaction(SIGINT, &sa, &osa);
 145                 cleanup_push(&osa, sigint_cleanup);
 146                 (void)sigprocmask(SIG_UNBLOCK, &set, &oset);
 147                 cleanup_push(&oset, sigprocmask_cleanup);
 148                 while ((len = xread(f, buf, sizeof(buf))) > 0)
 149                     (void) xwrite(SHOUT, buf, len);
 150                 cleanup_until(&f);
 151 #ifdef convex
 152                 /* print error in case file is migrated */
 153                 if (len == -1)
 154                     stderror(ERR_SYSTEM, progname, strerror(errno));
 155 #endif /* convex */
 156                 break;
 157             }
 158         }
 159     }
 160     cleanup_until(name);
 161 }
 162
 163 static void
 164 /*ARGSUSED*/
 165 cleanf(int snum)
 166 {
 167     USE(snum);
 168     if (f != -1)
 169         xclose(f);
 170     f = -1;
 171 }
 172
 173 /* these next two are stolen from CMU's man(1) command for looking down
 174  * paths.  they are prety straight forward. */
 175
 176 /*
 177  * nextslist takes a search list and copies the next path in it
 178  * to np.  A null search list entry is expanded to ".".
 179  * If there are no entries in the search list, then np will point
 180  * to a null string.
 181  */
 182
 183 static void
 184 nextslist(const Char *sl, Char *np)
 185 {
 186     if (!*sl)
 187         *np = '\000';
 188     else if (*sl == ':') {
 189         *np++ = '.';
 190         *np = '\000';
 191     }
 192     else {
 193         while (*sl && *sl != ':')
 194             *np++ = *sl++;
 195         *np = '\000';
 196     }
 197 }
 198
 199 /*
 200  * skipslist returns the pointer to the next entry in the search list.
 201  */
 202
 203 static Char *
 204 skipslist(Char *sl)
 205 {
 206     while (*sl && *sl++ != ':')
 207         continue;
 208     return (sl);
 209 }