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
do_help(const Char * command)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*/
cleanf(int snum)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
nextslist(const Char * sl,Char * np)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 *
skipslist(Char * sl)200 skipslist(Char *sl)
201 {
202 while (*sl && *sl++ != ':')
203 continue;
204 return (sl);
205 }
206