contrib/tcsh/tw.help.c

   1 /* $Header: /src/pub/tcsh/tw.help.c,v 3.18 2002/03/08 17:36:47 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("$Id: tw.help.c,v 3.18 2002/03/08 17:36:47 christos Exp $")
  39
  40 #include "tw.h"
  41 #include "tc.h"
  42
  43
  44 static int f = -1;
  45 static  sigret_t         cleanf         __P((int));
  46 static  Char            *skipslist      __P((Char *));
  47 static  void             nextslist      __P((Char *, Char *));
  48
  49 static char *h_ext[] = {
  50     ".help", ".1", ".8", ".6", "", NULL
  51 };
  52
  53 void
  54 do_help(command)
  55     Char   *command;
  56 {
  57     Char    name[FILSIZ + 1];
  58     Char   *cmd_p, *ep;
  59     char  **sp;
  60
  61     signalfun_t orig_intr;
  62     Char    curdir[MAXPATHLEN]; /* Current directory being looked at */
  63     register Char *hpath;       /* The environment parameter */
  64     Char    full[MAXPATHLEN];
  65     char    buf[512];           /* full path name and buffer for read */
  66     int     len;                /* length of read buffer */
  67     Char   *thpath;
  68
  69
  70     /* trim off the whitespace at the beginning */
  71     for (cmd_p = command; *cmd_p == ' ' || *cmd_p == '\t'; cmd_p++)
  72         continue;
  73
  74     /* copy the string to a safe place */
  75     copyn(name, cmd_p, FILSIZ + 1);
  76
  77     /* trim off the whitespace that may be at the end */
  78     for (cmd_p = name;
  79          *cmd_p != ' ' && *cmd_p != '\t' && *cmd_p != '\0'; cmd_p++)
  80         continue;
  81     *cmd_p = '\0';
  82
  83     /* if nothing left, return */
  84     if (*name == '\0')
  85         return;
  86
  87     if (adrof1(STRhelpcommand, &aliases)) {     /* if we have an alias */
  88         jmp_buf_t osetexit;
  89
  90         getexit(osetexit);      /* make sure to come back here */
  91         if (setexit() == 0)
  92             aliasrun(2, STRhelpcommand, name);  /* then use it. */
  93         resexit(osetexit);      /* and finish up */
  94     }
  95     else {                      /* else cat something to them */
  96         /* got is, now "cat" the file based on the path $HPATH */
  97
  98         hpath = str2short(getenv(SEARCHLIST));
  99         if (hpath == NULL)
 100             hpath = str2short(DEFAULTLIST);
 101         thpath = hpath = Strsave(hpath);
 102
 103         for (;;) {
 104             if (!*hpath) {
 105                 xprintf(CGETS(29, 1, "No help file for %S\n"), name);
 106                 break;
 107             }
 108             nextslist(hpath, curdir);
 109             hpath = skipslist(hpath);
 110
 111             /*
 112              * now make the full path name - try first /bar/foo.help, then
 113              * /bar/foo.1, /bar/foo.8, then finally /bar/foo.6.  This is so
 114              * that you don't spit a binary at the tty when $HPATH == $PATH.
 115              */
 116             copyn(full, curdir, (int) (sizeof(full) / sizeof(Char)));
 117             catn(full, STRslash, (int) (sizeof(full) / sizeof(Char)));
 118             catn(full, name, (int) (sizeof(full) / sizeof(Char)));
 119             ep = &full[Strlen(full)];
 120             for (sp = h_ext; *sp; sp++) {
 121                 *ep = '\0';
 122                 catn(full, str2short(*sp), (int) (sizeof(full) / sizeof(Char)));
 123                 if ((f = open(short2str(full), O_RDONLY)) != -1)
 124                     break;
 125             }
 126             if (f != -1) {
 127                 /* so cat it to the terminal */
 128                 orig_intr = (signalfun_t) sigset(SIGINT, cleanf);
 129                 while (f != -1 && (len = read(f, (char *) buf, 512)) > 0)
 130                     (void) write(SHOUT, (char *) buf, (size_t) len);
 131 #ifdef convex
 132                 /* print error in case file is migrated */
 133                 if (len == -1)
 134                     stderror(ERR_SYSTEM, progname, strerror(errno));
 135 #endif /* convex */
 136                 (void) sigset(SIGINT, orig_intr);
 137                 if (f != -1)
 138                     (void) close(f);
 139                 break;
 140             }
 141         }
 142         xfree((ptr_t) thpath);
 143     }
 144 }
 145
 146 static  sigret_t
 147 /*ARGSUSED*/
 148 cleanf(snum)
 149 int snum;
 150 {
 151     USE(snum);
 152 #ifdef UNRELSIGS
 153     if (snum)
 154         (void) sigset(SIGINT, cleanf);
 155 #endif /* UNRELSIGS */
 156     if (f != -1)
 157         (void) close(f);
 158     f = -1;
 159 #ifndef SIGVOID
 160     return (snum);
 161 #endif
 162 }
 163
 164 /* these next two are stolen from CMU's man(1) command for looking down
 165  * paths.  they are prety straight forward. */
 166
 167 /*
 168  * nextslist takes a search list and copies the next path in it
 169  * to np.  A null search list entry is expanded to ".".
 170  * If there are no entries in the search list, then np will point
 171  * to a null string.
 172  */
 173
 174 static void
 175 nextslist(sl, np)
 176     register Char *sl;
 177     register Char *np;
 178 {
 179     if (!*sl)
 180         *np = '\000';
 181     else if (*sl == ':') {
 182         *np++ = '.';
 183         *np = '\000';
 184     }
 185     else {
 186         while (*sl && *sl != ':')
 187             *np++ = *sl++;
 188         *np = '\000';
 189     }
 190 }
 191
 192 /*
 193  * skipslist returns the pointer to the next entry in the search list.
 194  */
 195
 196 static Char *
 197 skipslist(sl)
 198     register Char *sl;
 199 {
 200     while (*sl && *sl++ != ':')
 201         continue;
 202     return (sl);
 203 }