help.c revision d2021de5cf94d7a55181004beee296b310901718 
1/*
2 * Copyright 1987, 1988 by MIT Student Information Processing Board
3 *
4 * Permission to use, copy, modify, and distribute this software and
5 * its documentation for any purpose is hereby granted, provided that
6 * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in
7 * advertising or publicity pertaining to distribution of the software
8 * without specific, written prior permission.  M.I.T. and the
9 * M.I.T. S.I.P.B. make no representations about the suitability of
10 * this software for any purpose.  It is provided "as is" without
11 * express or implied warranty.
12 */
13
14#ifdef HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17#ifdef HAVE_STDLIB_H
18#include <stdlib.h>
19#endif
20#ifdef HAVE_ERRNO_H
21#include <errno.h>
22#else
23extern int errno;
24#endif
25#include <fcntl.h>
26#include <sys/param.h>
27#include <sys/types.h>
28#include <sys/file.h>
29#ifdef NEED_SYS_FCNTL_H
30/* just for O_* */
31#include <sys/fcntl.h>
32#endif
33#ifdef HAVE_SYS_WAIT_H
34#include <sys/wait.h>
35#endif
36#include "ss_internal.h"
37
38void ss_help (argc, argv, sci_idx, info_ptr)
39    int argc;
40    char const * const *argv;
41    int sci_idx;
42    pointer info_ptr;
43{
44    char *buffer;
45    char const *request_name;
46    int code;
47    int fd, child;
48    register int idx;
49    register ss_data *info;
50
51    request_name = ss_current_request(sci_idx, &code);
52    if (code != 0) {
53	ss_perror(sci_idx, code, "");
54	return;		/* no ss_abort_line, if invalid invocation */
55    }
56    if (argc == 1) {
57	ss_list_requests(argc, argv, sci_idx, info_ptr);
58	return;
59    }
60    else if (argc != 2) {
61	/* should do something better than this */
62	buffer = malloc(80+2*strlen(request_name));
63	if (!buffer) {
64		ss_perror(sci_idx, 0,
65			  "couldn't allocate memory to print usage message");
66		return;
67	}
68	sprintf(buffer, "usage:\n\t%s [topic|command]\nor\t%s\n",
69		request_name, request_name);
70	ss_perror(sci_idx, 0, buffer);
71	free(buffer);
72	return;
73    }
74    info = ss_info(sci_idx);
75    if (info->info_dirs == (char **)NULL) {
76	ss_perror(sci_idx, SS_ET_NO_INFO_DIR, (char *)NULL);
77	return;
78    }
79    if (info->info_dirs[0] == (char *)NULL) {
80	ss_perror(sci_idx, SS_ET_NO_INFO_DIR, (char *)NULL);
81	return;
82    }
83    for (fd = -1, idx = 0; info->info_dirs[idx] != (char *)NULL; idx++) {
84        buffer = malloc(strlen (info->info_dirs[idx]) + 1 +
85			strlen (argv[1]) + 6);
86	if (!buffer) {
87	    ss_perror(sci_idx, 0,
88		      "couldn't allocate memory for help filename");
89	    return;
90	}
91	(void) strcpy(buffer, info->info_dirs[idx]);
92	(void) strcat(buffer, "/");
93	(void) strcat(buffer, argv[1]);
94	(void) strcat(buffer, ".info");
95	fd = open(buffer, O_RDONLY);
96	free(buffer);
97	if (fd >= 0)
98	    break;
99    }
100    if (fd < 0) {
101#define MSG "No info found for "
102        char *buf = malloc(strlen (MSG) + strlen (argv[1]) + 1);
103	strcpy(buf, MSG);
104	strcat(buf, argv[1]);
105	ss_perror(sci_idx, 0, buf);
106	free(buf);
107	return;
108    }
109    switch (child = fork()) {
110    case -1:
111	ss_perror(sci_idx, errno, "Can't fork for pager");
112	return;
113    case 0:
114	(void) dup2(fd, 0); /* put file on stdin */
115	ss_page_stdin();
116    default:
117	(void) close(fd); /* what can we do if it fails? */
118	while (wait(0) != child) {
119	    /* do nothing if wrong pid */
120	};
121    }
122}
123
124#ifndef HAVE_DIRENT_H
125#include <sys/dir.h>
126#else
127#include <dirent.h>
128#endif
129
130void ss_add_info_dir(sci_idx, info_dir, code_ptr)
131    int sci_idx;
132    char *info_dir;
133    int *code_ptr;
134{
135    register ss_data *info;
136    DIR *d;
137    int n_dirs;
138    register char **dirs;
139
140    info = ss_info(sci_idx);
141    if (info_dir == NULL || *info_dir == '\0') {
142	*code_ptr = SS_ET_NO_INFO_DIR;
143	return;
144    }
145    if ((d = opendir(info_dir)) == (DIR *)NULL) {
146	*code_ptr = errno;
147	return;
148    }
149    closedir(d);
150    dirs = info->info_dirs;
151    for (n_dirs = 0; dirs[n_dirs] != (char *)NULL; n_dirs++)
152	;		/* get number of non-NULL dir entries */
153    dirs = (char **)realloc((char *)dirs,
154			    (unsigned)(n_dirs + 2)*sizeof(char *));
155    if (dirs == (char **)NULL) {
156	info->info_dirs = (char **)NULL;
157	*code_ptr = errno;
158	return;
159    }
160    info->info_dirs = dirs;
161    dirs[n_dirs + 1] = (char *)NULL;
162    dirs[n_dirs] = malloc((unsigned)strlen(info_dir)+1);
163    strcpy(dirs[n_dirs], info_dir);
164    *code_ptr = 0;
165}
166
167void ss_delete_info_dir(sci_idx, info_dir, code_ptr)
168    int sci_idx;
169    char *info_dir;
170    int *code_ptr;
171{
172    register char **i_d;
173    register char **info_dirs;
174
175    info_dirs = ss_info(sci_idx)->info_dirs;
176    for (i_d = info_dirs; *i_d; i_d++) {
177	if (!strcmp(*i_d, info_dir)) {
178	    while (*i_d) {
179		*i_d = *(i_d+1);
180		i_d++;
181	    }
182	    *code_ptr = 0;
183	    return;
184	}
185    }
186    *code_ptr = SS_ET_NO_INFO_DIR;
187}
188