help.c revision f404167dda29a59d2be2882328aeb074b9899669 
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#include "config.h"
15#ifdef HAVE_UNISTD_H
16#include <unistd.h>
17#endif
18#ifdef HAVE_STDLIB_H
19#include <stdlib.h>
20#endif
21#ifdef HAVE_ERRNO_H
22#include <errno.h>
23#else
24extern int errno;
25#endif
26#include <fcntl.h>
27#include <sys/param.h>
28#include <sys/types.h>
29#include <sys/file.h>
30#ifdef NEED_SYS_FCNTL_H
31/* just for O_* */
32#include <sys/fcntl.h>
33#endif
34#ifdef HAVE_SYS_WAIT_H
35#include <sys/wait.h>
36#endif
37#include "ss_internal.h"
38
39void ss_help(int argc, char const * const *argv, int sci_idx, pointer info_ptr)
40{
41    char *buffer;
42    char const *request_name;
43    int code;
44    int fd, child;
45    register int idx;
46    register ss_data *info;
47
48    request_name = ss_current_request(sci_idx, &code);
49    if (code != 0) {
50	ss_perror(sci_idx, code, "");
51	return;		/* no ss_abort_line, if invalid invocation */
52    }
53    if (argc == 1) {
54	ss_list_requests(argc, argv, sci_idx, info_ptr);
55	return;
56    }
57    else if (argc != 2) {
58	/* should do something better than this */
59	buffer = malloc(80+2*strlen(request_name));
60	if (!buffer) {
61		ss_perror(sci_idx, 0,
62			  "couldn't allocate memory to print usage message");
63		return;
64	}
65	sprintf(buffer, "usage:\n\t%s [topic|command]\nor\t%s\n",
66		request_name, request_name);
67	ss_perror(sci_idx, 0, buffer);
68	free(buffer);
69	return;
70    }
71    info = ss_info(sci_idx);
72    if (info->info_dirs == (char **)NULL) {
73	ss_perror(sci_idx, SS_ET_NO_INFO_DIR, (char *)NULL);
74	return;
75    }
76    if (info->info_dirs[0] == (char *)NULL) {
77	ss_perror(sci_idx, SS_ET_NO_INFO_DIR, (char *)NULL);
78	return;
79    }
80    for (fd = -1, idx = 0; info->info_dirs[idx] != (char *)NULL; idx++) {
81        buffer = malloc(strlen (info->info_dirs[idx]) + 1 +
82			strlen (argv[1]) + 6);
83	if (!buffer) {
84	    ss_perror(sci_idx, 0,
85		      "couldn't allocate memory for help filename");
86	    return;
87	}
88	(void) strcpy(buffer, info->info_dirs[idx]);
89	(void) strcat(buffer, "/");
90	(void) strcat(buffer, argv[1]);
91	(void) strcat(buffer, ".info");
92	fd = open(buffer, O_RDONLY);
93	free(buffer);
94	if (fd >= 0)
95	    break;
96    }
97    if (fd < 0) {
98#define MSG "No info found for "
99        char *buf = malloc(strlen (MSG) + strlen (argv[1]) + 1);
100	strcpy(buf, MSG);
101	strcat(buf, argv[1]);
102	ss_perror(sci_idx, 0, buf);
103	free(buf);
104	return;
105    }
106    switch (child = fork()) {
107    case -1:
108	ss_perror(sci_idx, errno, "Can't fork for pager");
109	(void) close(fd);
110	return;
111    case 0:
112	(void) dup2(fd, 0); /* put file on stdin */
113	ss_page_stdin();
114    default:
115	(void) close(fd); /* what can we do if it fails? */
116	while (wait(NULL) != child) {
117	    /* do nothing if wrong pid */
118	};
119    }
120}
121
122#ifndef HAVE_DIRENT_H
123#include <sys/dir.h>
124#else
125#include <dirent.h>
126#endif
127
128void ss_add_info_dir(int sci_idx, char *info_dir, int *code_ptr)
129{
130    register ss_data *info;
131    DIR *d;
132    int n_dirs;
133    register char **dirs;
134
135    info = ss_info(sci_idx);
136    if (info_dir == NULL || *info_dir == '\0') {
137	*code_ptr = SS_ET_NO_INFO_DIR;
138	return;
139    }
140    if ((d = opendir(info_dir)) == (DIR *)NULL) {
141	*code_ptr = errno;
142	return;
143    }
144    closedir(d);
145    dirs = info->info_dirs;
146    for (n_dirs = 0; dirs[n_dirs] != (char *)NULL; n_dirs++)
147	;		/* get number of non-NULL dir entries */
148    dirs = (char **)realloc((char *)dirs,
149			    (unsigned)(n_dirs + 2)*sizeof(char *));
150    if (dirs == (char **)NULL) {
151	info->info_dirs = (char **)NULL;
152	*code_ptr = errno;
153	return;
154    }
155    info->info_dirs = dirs;
156    dirs[n_dirs + 1] = (char *)NULL;
157    dirs[n_dirs] = malloc((unsigned)strlen(info_dir)+1);
158    strcpy(dirs[n_dirs], info_dir);
159    *code_ptr = 0;
160}
161
162void ss_delete_info_dir(int sci_idx, char *info_dir, int *code_ptr)
163{
164    register char **i_d;
165    register char **info_dirs;
166
167    info_dirs = ss_info(sci_idx)->info_dirs;
168    for (i_d = info_dirs; *i_d; i_d++) {
169	if (!strcmp(*i_d, info_dir)) {
170	    while (*i_d) {
171		*i_d = *(i_d+1);
172		i_d++;
173	    }
174	    *code_ptr = 0;
175	    return;
176	}
177    }
178    *code_ptr = SS_ET_NO_INFO_DIR;
179}
180