1/* vi: set sw=4 ts=4: */
2/*
3 * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
4 *
5 * Copyright 1999 George Staikos
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 *
9 * Changelog:
10 *	v1.01:
11 *		- added -p <preload> to preload values from a file
12 *	v1.01.1
13 *		- busybox applet aware by <solar@gentoo.org>
14 *
15 */
16
17#include "libbb.h"
18
19/*
20 *    Function Prototypes
21 */
22static int sysctl_read_setting(const char *setting, int output);
23static int sysctl_write_setting(const char *setting, int output);
24static int sysctl_preload_file(const char *filename, int output);
25static int sysctl_display_all(const char *path, int output, int show_table);
26
27/*
28 *    Globals...
29 */
30static const char PROC_PATH[] ALIGN1 = "/proc/sys/";
31static const char DEFAULT_PRELOAD[] ALIGN1 = "/etc/sysctl.conf";
32
33/* error messages */
34static const char ERR_UNKNOWN_PARAMETER[] ALIGN1 =
35	"error: Unknown parameter '%s'\n";
36static const char ERR_MALFORMED_SETTING[] ALIGN1 =
37	"error: Malformed setting '%s'\n";
38static const char ERR_NO_EQUALS[] ALIGN1 =
39	"error: '%s' must be of the form name=value\n";
40static const char ERR_INVALID_KEY[] ALIGN1 =
41	"error: '%s' is an unknown key\n";
42static const char ERR_UNKNOWN_WRITING[] ALIGN1 =
43	"error: unknown error %d setting key '%s'\n";
44static const char ERR_UNKNOWN_READING[] ALIGN1 =
45	"error: unknown error %d reading key '%s'\n";
46static const char ERR_PERMISSION_DENIED[] ALIGN1 =
47	"error: permission denied on key '%s'\n";
48static const char ERR_PRELOAD_FILE[] ALIGN1 =
49	"error: cannot open preload file '%s'\n";
50static const char WARN_BAD_LINE[] ALIGN1 =
51	"warning: %s(%d): invalid syntax, continuing...\n";
52
53
54static void dwrite_str(int fd, const char *buf)
55{
56	write(fd, buf, strlen(buf));
57}
58
59/*
60 *    sysctl_main()...
61 */
62int sysctl_main(int argc, char **argv);
63int sysctl_main(int argc, char **argv)
64{
65	int retval = 0;
66	int output = 1;
67	int write_mode = 0;
68	int switches_allowed = 1;
69
70	if (argc < 2)
71		bb_show_usage();
72
73	argv++;
74
75	for (; argv && *argv && **argv; argv++) {
76		if (switches_allowed && **argv == '-') {	/* we have a switch */
77			switch ((*argv)[1]) {
78			case 'n':
79				output = 0;
80				break;
81			case 'w':
82				write_mode = 1;
83				switches_allowed = 0;
84				break;
85			case 'p':
86				argv++;
87				return
88					sysctl_preload_file(((argv && *argv
89										  && **argv) ? *argv :
90										 DEFAULT_PRELOAD), output);
91			case 'a':
92			case 'A':
93				switches_allowed = 0;
94				return sysctl_display_all(PROC_PATH, output,
95										  ((*argv)[1] == 'a') ? 0 : 1);
96			case 'h':
97			case '?':
98				bb_show_usage();
99			default:
100				bb_error_msg(ERR_UNKNOWN_PARAMETER, *argv);
101				bb_show_usage();
102			}
103		} else {
104			switches_allowed = 0;
105			if (write_mode)
106				retval = sysctl_write_setting(*argv, output);
107			else
108				sysctl_read_setting(*argv, output);
109		}
110	}
111	return retval;
112}						/* end sysctl_main() */
113
114
115
116/*
117 *     sysctl_preload_file
118 *	preload the sysctl's from a conf file
119 *           - we parse the file and then reform it (strip out whitespace)
120 */
121#define PRELOAD_BUF 256
122
123int sysctl_preload_file(const char *filename, int output)
124{
125	int lineno = 0;
126	char oneline[PRELOAD_BUF];
127	char buffer[PRELOAD_BUF];
128	char *name, *value, *ptr;
129	FILE *fp = NULL;
130
131	if (!filename || ((fp = fopen(filename, "r")) == NULL)) {
132		bb_error_msg_and_die(ERR_PRELOAD_FILE, filename);
133	}
134
135	while (fgets(oneline, sizeof(oneline) - 1, fp)) {
136		oneline[sizeof(oneline) - 1] = '\0';
137		lineno++;
138		trim(oneline);
139		ptr = (char *) oneline;
140
141		if (*ptr == '#' || *ptr == ';')
142			continue;
143
144		if (strlen(ptr) < 2)
145			continue;
146
147		name = strtok(ptr, "=");
148		if (!name || !*name) {
149			bb_error_msg(WARN_BAD_LINE, filename, lineno);
150			continue;
151		}
152
153		trim(name);
154
155		value = strtok(NULL, "\n\r");
156		if (!value || !*value) {
157			bb_error_msg(WARN_BAD_LINE, filename, lineno);
158			continue;
159		}
160
161		while ((*value == ' ' || *value == '\t') && *value != 0)
162			value++;
163		/* safe because sizeof(oneline) == sizeof(buffer) */
164		sprintf(buffer, "%s=%s", name, value);
165		sysctl_write_setting(buffer, output);
166	}
167	fclose(fp);
168	return 0;
169}						/* end sysctl_preload_file() */
170
171
172/*
173 *     Write a single sysctl setting
174 */
175int sysctl_write_setting(const char *setting, int output)
176{
177	int retval = 0;
178	const char *name = setting;
179	const char *value;
180	const char *equals;
181	char *tmpname, *outname, *cptr;
182	int fd = -1;
183
184	if (!name)			/* probably dont' want to display this  err */
185		return 0;
186
187	if (!(equals = strchr(setting, '='))) {
188		bb_error_msg(ERR_NO_EQUALS, setting);
189		return -1;
190	}
191
192	value = equals + sizeof(char);	/* point to the value in name=value */
193
194	if (!*name || !*value || name == equals) {
195		bb_error_msg(ERR_MALFORMED_SETTING, setting);
196		return -2;
197	}
198
199	tmpname = xasprintf("%s%.*s", PROC_PATH, (int)(equals - name), name);
200	outname = xstrdup(tmpname + strlen(PROC_PATH));
201
202	while ((cptr = strchr(tmpname, '.')) != NULL)
203		*cptr = '/';
204
205	while ((cptr = strchr(outname, '/')) != NULL)
206		*cptr = '.';
207
208	fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
209	if (fd < 0) {
210		switch (errno) {
211		case ENOENT:
212			bb_error_msg(ERR_INVALID_KEY, outname);
213			break;
214		case EACCES:
215			bb_perror_msg(ERR_PERMISSION_DENIED, outname);
216			break;
217		default:
218			bb_error_msg(ERR_UNKNOWN_WRITING, errno, outname);
219			break;
220		}
221		retval = -1;
222	} else {
223		dwrite_str(fd, value);
224		close(fd);
225		if (output) {
226			dwrite_str(STDOUT_FILENO, outname);
227			dwrite_str(STDOUT_FILENO, " = ");
228		}
229		dwrite_str(STDOUT_FILENO, value);
230		dwrite_str(STDOUT_FILENO, "\n");
231	}
232
233	/* cleanup */
234	free(tmpname);
235	free(outname);
236	return retval;
237}						/* end sysctl_write_setting() */
238
239
240/*
241 *     Read a sysctl setting
242 *
243 */
244int sysctl_read_setting(const char *setting, int output)
245{
246	int retval = 0;
247	char *tmpname, *outname, *cptr;
248	char inbuf[1025];
249	const char *name = setting;
250	FILE *fp;
251
252	if (!setting || !*setting)
253		bb_error_msg(ERR_INVALID_KEY, setting);
254
255	tmpname = concat_path_file(PROC_PATH, name);
256	outname = xstrdup(tmpname + strlen(PROC_PATH));
257
258	while ((cptr = strchr(tmpname, '.')) != NULL)
259		*cptr = '/';
260	while ((cptr = strchr(outname, '/')) != NULL)
261		*cptr = '.';
262
263	if ((fp = fopen(tmpname, "r")) == NULL) {
264		switch (errno) {
265		case ENOENT:
266			bb_error_msg(ERR_INVALID_KEY, outname);
267			break;
268		case EACCES:
269			bb_error_msg(ERR_PERMISSION_DENIED, outname);
270			break;
271		default:
272			bb_error_msg(ERR_UNKNOWN_READING, errno, outname);
273			break;
274		}
275		retval = -1;
276	} else {
277		while (fgets(inbuf, sizeof(inbuf) - 1, fp)) {
278			if (output) {
279				dwrite_str(STDOUT_FILENO, outname);
280				dwrite_str(STDOUT_FILENO, " = ");
281			}
282			dwrite_str(STDOUT_FILENO, inbuf);
283		}
284		fclose(fp);
285	}
286
287	free(tmpname);
288	free(outname);
289	return retval;
290}						/* end sysctl_read_setting() */
291
292
293
294/*
295 *     Display all the sysctl settings
296 *
297 */
298int sysctl_display_all(const char *path, int output, int show_table)
299{
300	int retval = 0;
301	int retval2;
302	DIR *dp;
303	struct dirent *de;
304	char *tmpdir;
305	struct stat ts;
306
307	dp = opendir(path);
308	if (!dp) {
309		retval = -1;
310	} else {
311		while ((de = readdir(dp)) != NULL) {
312			tmpdir = concat_subpath_file(path, de->d_name);
313			if (tmpdir == NULL)
314				continue;
315			retval2 = stat(tmpdir, &ts);
316			if (retval2 != 0)
317				bb_perror_msg(tmpdir);
318			else {
319				if (S_ISDIR(ts.st_mode)) {
320					sysctl_display_all(tmpdir, output, show_table);
321				} else
322					retval |=
323						sysctl_read_setting(tmpdir + strlen(PROC_PATH),
324											output);
325
326			}
327			free(tmpdir);
328		}				/* end while */
329		closedir(dp);
330	}
331
332	return retval;
333}						/* end sysctl_display_all() */
334