contrib/tcsh-6/tw.help.c

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