busybox/applets/applets.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) tons of folks.  Tracking down who wrote what
 * isn't something I'm going to worry about...  If you wrote something
 * here, please feel free to acknowledge your work.
 *
 * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
 * Permission has been granted to redistribute this code under the GPL.
 *
 * Licensed under GPLv2 or later, see file License in this tarball for details.
 */

#include "busybox.h"
#include <assert.h>

/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
#if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
#warning Static linking against glibc produces buggy executables
#warning (glibc does not cope well with ld --gc-sections).
#warning See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
#warning Note that glibc is unsuitable for static linking anyway.
#warning If you still want to do it, remove -Wl,--gc-sections
#warning from top-level Makefile and remove this warning.
#endif

#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
static const char usage_messages[] =
#define MAKE_USAGE
#include "usage.h"
#include "applets.h"
;
#undef MAKE_USAGE
#else
#define usage_messages 0
#endif /* ENABLE_SHOW_USAGE */

#undef APPLET
#undef APPLET_NOUSAGE
#undef PROTOTYPES
#include "applets.h"

static struct BB_applet *applet_using;

/* The -1 arises because of the {0,NULL,0,-1} entry above. */
const unsigned short NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);


#ifdef CONFIG_FEATURE_SUID_CONFIG

#include <ctype.h>

#define CONFIG_FILE "/etc/busybox.conf"

/* applets [] is const, so we have to define this "override" structure */
static struct BB_suid_config
{
	struct BB_applet *m_applet;

	uid_t m_uid;
	gid_t m_gid;
	mode_t m_mode;

	struct BB_suid_config *m_next;
} *suid_config;

static int suid_cfg_readable;

/* check if u is member of group g */
static int ingroup(uid_t u, gid_t g)
{
	struct group *grp = getgrgid(g);

	if (grp) {
		char **mem;

		for (mem = grp->gr_mem; *mem; mem++) {
			struct passwd *pwd = getpwnam(*mem);

			if (pwd && (pwd->pw_uid == u))
				return 1;
		}
	}
	return 0;
}

/* This should probably be a libbb routine.  In that case,
 * I'd probably rename it to something like bb_trimmed_slice.
 */
static char *get_trimmed_slice(char *s, char *e)
{
	/* First, consider the value at e to be nul and back up until we
	 * reach a non-space char.  Set the char after that (possibly at
	 * the original e) to nul. */
	while (e-- > s) {
		if (!isspace(*e)) {
			break;
		}
	}
	e[1] = 0;

	/* Next, advance past all leading space and return a ptr to the
	 * first non-space char; possibly the terminating nul. */
	return skip_whitespace(s);
}


#define parse_error(x)  { err=x; goto pe_label; }

/* Don't depend on the tools to combine strings. */
static const char config_file[] = CONFIG_FILE;

/* There are 4 chars + 1 nul for each of user/group/other. */
static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";

/* We don't supply a value for the nul, so an index adjustment is
 * necessary below.  Also, we use unsigned short here to save some
 * space even though these are really mode_t values. */
static const unsigned short mode_mask[] = {
	/*  SST         sst                 xxx   --- */
	S_ISUID,    S_ISUID|S_IXUSR,    S_IXUSR,    0,	/* user */
	S_ISGID,    S_ISGID|S_IXGRP,    S_IXGRP,    0,	/* group */
	0,          S_IXOTH,            S_IXOTH,    0	/* other */
};

static void parse_config_file(void)
{
	struct BB_suid_config *sct_head;
	struct BB_suid_config *sct;
	struct BB_applet *applet;
	FILE *f;
	char *err;
	char *s;
	char *e;
	int i, lc, section;
	char buffer[256];
	struct stat st;

	assert(!suid_config);		/* Should be set to NULL by bss init. */

	if ((stat(config_file, &st) != 0)			/* No config file? */
		|| !S_ISREG(st.st_mode)					/* Not a regular file? */
		|| (st.st_uid != 0)						/* Not owned by root? */
		|| (st.st_mode & (S_IWGRP | S_IWOTH))	/* Writable by non-root? */
		|| !(f = fopen(config_file, "r"))		/* Cannot open? */
		) {
		return;
	}

	suid_cfg_readable = 1;
	sct_head = NULL;
	section = lc = 0;

	do {
		s = buffer;

		if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
			if (ferror(f)) {   /* Make sure it wasn't a read error. */
				parse_error("reading");
			}
			fclose(f);
			suid_config = sct_head;	/* Success, so set the pointer. */
			return;
		}

		lc++;					/* Got a (partial) line. */

		/* If a line is too long for our buffer, we consider it an error.
		 * The following test does mistreat one corner case though.
		 * If the final line of the file does not end with a newline and
		 * yet exactly fills the buffer, it will be treated as too long
		 * even though there isn't really a problem.  But it isn't really
		 * worth adding code to deal with such an unlikely situation, and
		 * we do err on the side of caution.  Besides, the line would be
		 * too long if it did end with a newline. */
		if (!strchr(s, '\n') && !feof(f)) {
			parse_error("line too long");
		}

		/* Trim leading and trailing whitespace, ignoring comments, and
		 * check if the resulting string is empty. */
		if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) {
			continue;
		}

		/* Check for a section header. */

		if (*s == '[') {
			/* Unlike the old code, we ignore leading and trailing
			 * whitespace for the section name.  We also require that
			 * there are no stray characters after the closing bracket. */
			if (!(e = strchr(s, ']'))	/* Missing right bracket? */
				|| e[1]					/* Trailing characters? */
				|| !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
				) {
				parse_error("section header");
			}
			/* Right now we only have one section so just check it.
			 * If more sections are added in the future, please don't
			 * resort to cascading ifs with multiple strcasecmp calls.
			 * That kind of bloated code is all too common.  A loop
			 * and a string table would be a better choice unless the
			 * number of sections is very small. */
			if (strcasecmp(s, "SUID") == 0) {
				section = 1;
				continue;
			}
			section = -1;	/* Unknown section so set to skip. */
			continue;
		}

		/* Process sections. */

		if (section == 1) {		/* SUID */
			/* Since we trimmed leading and trailing space above, we're
			 * now looking for strings of the form
			 *    <key>[::space::]*=[::space::]*<value>
			 * where both key and value could contain inner whitespace. */

			/* First get the key (an applet name in our case). */
			if (!!(e = strchr(s, '='))) {
				s = get_trimmed_slice(s, e);
			}
			if (!e || !*s) {	/* Missing '=' or empty key. */
				parse_error("keyword");
			}

			/* Ok, we have an applet name.  Process the rhs if this
			 * applet is currently built in and ignore it otherwise.
			 * Note: This can hide config file bugs which only pop
			 * up when the busybox configuration is changed. */
			if ((applet = find_applet_by_name(s))) {
				/* Note: We currently don't check for duplicates!
				 * The last config line for each applet will be the
				 * one used since we insert at the head of the list.
				 * I suppose this could be considered a feature. */
				sct = xmalloc(sizeof(struct BB_suid_config));
				sct->m_applet = applet;
				sct->m_mode = 0;
				sct->m_next = sct_head;
				sct_head = sct;

				/* Get the specified mode. */

				e = skip_whitespace(e+1);

				for (i=0 ; i < 3 ; i++) {
					const char *q;
					if (!*(q = strchrnul(mode_chars + 5*i, *e++))) {
						parse_error("mode");
					}
					/* Adjust by -i to account for nul. */
					sct->m_mode |= mode_mask[(q - mode_chars) - i];
				}

				/* Now get the the user/group info. */

				s = skip_whitespace(e);

				/* Note: We require whitespace between the mode and the
				 * user/group info. */
				if ((s == e) || !(e = strchr(s, '.'))) {
					parse_error("<uid>.<gid>");
				}
				*e++ = 0;

				/* We can't use get_ug_id here since it would exit()
				 * if a uid or gid was not found.  Oh well... */
				{
					char *e2;

					sct->m_uid = strtoul(s, &e2, 10);
					if (*e2 || (s == e2)) {
						struct passwd *pwd = getpwnam(s);
						if (!pwd) {
							parse_error("user");
						}
						sct->m_uid = pwd->pw_uid;
					}

					sct->m_gid = strtoul(e, &e2, 10);
					if (*e2 || (e == e2)) {
						struct group *grp;
						if (!(grp = getgrnam(e))) {
							parse_error("group");
						}
						sct->m_gid = grp->gr_gid;
					}
				}
			}
			continue;
		}

		/* Unknown sections are ignored. */

		/* Encountering configuration lines prior to seeing a
		 * section header is treated as an error.  This is how
		 * the old code worked, but it may not be desirable.
		 * We may want to simply ignore such lines in case they
		 * are used in some future version of busybox. */
		if (!section) {
			parse_error("keyword outside section");
		}

	} while (1);

 pe_label:
	fprintf(stderr, "Parse error in %s, line %d: %s\n",
			config_file, lc, err);

	fclose(f);
	/* Release any allocated memory before returning. */
	while (sct_head) {
		sct = sct_head->m_next;
		free(sct_head);
		sct_head = sct;
	}
	return;
}

#else
#define parse_config_file() ((void)0)
#endif /* CONFIG_FEATURE_SUID_CONFIG */

#ifdef CONFIG_FEATURE_SUID
static void check_suid(struct BB_applet *applet)
{
	uid_t ruid = getuid();               /* real [ug]id */
	uid_t rgid = getgid();

#ifdef CONFIG_FEATURE_SUID_CONFIG
	if (suid_cfg_readable) {
		struct BB_suid_config *sct;

		for (sct = suid_config; sct; sct = sct->m_next) {
			if (sct->m_applet == applet)
				break;
		}
		if (sct) {
			mode_t m = sct->m_mode;

			if (sct->m_uid == ruid)
				/* same uid */
				m >>= 6;
			else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
				/* same group / in group */
				m >>= 3;

			if (!(m & S_IXOTH))           /* is x bit not set ? */
				bb_error_msg_and_die("you have no permission to run this applet!");

			if (sct->m_gid != 0) {
				/* _both_ have to be set for sgid */
				if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
					xsetgid(sct->m_gid);
				} else xsetgid(rgid); /* no sgid -> drop */
			}
			if (sct->m_uid != 0) {
				if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
				else xsetuid(ruid); /* no suid -> drop */
			}
		} else {
			/* default: drop all privileges */
			xsetgid(rgid);
			xsetuid(ruid);
		}
		return;
	} else {
#ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
		static int onetime = 0;

		if (!onetime) {
			onetime = 1;
			fprintf(stderr, "Using fallback suid method\n");
		}
#endif
	}
#endif

	if (applet->need_suid == _BB_SUID_ALWAYS) {
		if (geteuid()) bb_error_msg_and_die("applet requires root privileges!");
	} else if (applet->need_suid == _BB_SUID_NEVER) {
		xsetgid(rgid);                          /* drop all privileges */
		xsetuid(ruid);
	}
}
#else
#define check_suid(x)
#endif /* CONFIG_FEATURE_SUID */


#ifdef CONFIG_FEATURE_COMPRESS_USAGE

#include "usage_compressed.h"
#include "unarchive.h"

static const char *unpack_usage_messages(void)
{
	int input[2], output[2], pid;
	char *buf;

	if(pipe(input) < 0 || pipe(output) < 0)
		exit(1);

	pid = fork();
	switch (pid) {
	case -1: /* error */
		exit(1);
	case 0: /* child */
		close(input[1]);
		close(output[0]);
		uncompressStream(input[0], output[1]);
		exit(0);
	}
	/* parent */

	close(input[0]);
	close(output[1]);
	pid = fork();
	switch (pid) {
	case -1: /* error */
		exit(1);
	case 0: /* child */
		full_write(input[1], packed_usage, sizeof(packed_usage));
		exit(0);
	}
	/* parent */
	close(input[1]);

	buf = xmalloc(SIZEOF_usage_messages);
	full_read(output[0], buf, SIZEOF_usage_messages);
	return buf;
}

#else
#define unpack_usage_messages() usage_messages
#endif /* ENABLE_FEATURE_COMPRESS_USAGE */

void bb_show_usage(void)
{
	if (ENABLE_SHOW_USAGE) {
		const char *format_string;
		const char *usage_string = unpack_usage_messages();
		int i;

		for (i = applet_using - applets; i > 0;)
			if (!*usage_string++) --i;

		format_string = "%s\n\nUsage: %s %s\n\n";
		if (*usage_string == '\b')
			format_string = "%s\n\nNo help available.\n\n";
		fprintf(stderr, format_string, bb_msg_full_version,
			applet_using->name, usage_string);
	}

	exit(xfunc_error_retval);
}

static int applet_name_compare(const void *name, const void *vapplet)
{
	const struct BB_applet *applet = vapplet;

	return strcmp(name, applet->name);
}

struct BB_applet *find_applet_by_name(const char *name)
{
	return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
				applet_name_compare);
}

void run_applet_by_name(const char *name, int argc, char **argv)
{
	if (ENABLE_FEATURE_SUID_CONFIG)
		parse_config_file();

	if (!strncmp(name, "busybox", 7))
		exit(busybox_main(argc, argv));
	/* Do a binary search to find the applet entry given the name. */
	applet_using = find_applet_by_name(name);
	if (applet_using) {
		applet_name = applet_using->name;
		if (argc == 2 && !strcmp(argv[1], "--help"))
			bb_show_usage();
		if (ENABLE_FEATURE_SUID)
			check_suid(applet_using);
		exit(applet_using->main(argc, argv));
	}
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Utility routines.
4	*
5	* Copyright (C) tons of folks. Tracking down who wrote what
6	* isn't something I'm going to worry about... If you wrote something
7	* here, please feel free to acknowledge your work.
8	*
9	* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
10	* Permission has been granted to redistribute this code under the GPL.
11	*
12	* Licensed under GPLv2 or later, see file License in this tarball for details.
13	*/
14
15	#include "busybox.h"
16	#include <assert.h>
17
18	/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
19	#if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
20	#warning Static linking against glibc produces buggy executables
21	#warning (glibc does not cope well with ld --gc-sections).
22	#warning See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
23	#warning Note that glibc is unsuitable for static linking anyway.
24	#warning If you still want to do it, remove -Wl,--gc-sections
25	#warning from top-level Makefile and remove this warning.
26	#endif
27
28	#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
29	static const char usage_messages[] =
30	#define MAKE_USAGE
31	#include "usage.h"
32	#include "applets.h"
33	;
34	#undef MAKE_USAGE
35	#else
36	#define usage_messages 0
37	#endif /* ENABLE_SHOW_USAGE */
38
39	#undef APPLET
40	#undef APPLET_NOUSAGE
41	#undef PROTOTYPES
42	#include "applets.h"
43
44	static struct BB_applet *applet_using;
45
46	/* The -1 arises because of the {0,NULL,0,-1} entry above. */
47	const unsigned short NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);
48
49
50	#ifdef CONFIG_FEATURE_SUID_CONFIG
51
52	#include <ctype.h>
53
54	#define CONFIG_FILE "/etc/busybox.conf"
55
56	/* applets [] is const, so we have to define this "override" structure */
57	static struct BB_suid_config
58	{
59	struct BB_applet *m_applet;
60
61	uid_t m_uid;
62	gid_t m_gid;
63	mode_t m_mode;
64
65	struct BB_suid_config *m_next;
66	} *suid_config;
67
68	static int suid_cfg_readable;
69
70	/* check if u is member of group g */
71	static int ingroup(uid_t u, gid_t g)
72	{
73	struct group *grp = getgrgid(g);
74
75	if (grp) {
76	char **mem;
77
78	for (mem = grp->gr_mem; *mem; mem++) {
79	struct passwd pwd = getpwnam(mem);
80
81	if (pwd && (pwd->pw_uid == u))
82	return 1;
83	}
84	}
85	return 0;
86	}
87
88	/* This should probably be a libbb routine. In that case,
89	* I'd probably rename it to something like bb_trimmed_slice.
90	*/
91	static char get_trimmed_slice(char s, char *e)
92	{
93	/* First, consider the value at e to be nul and back up until we
94	* reach a non-space char. Set the char after that (possibly at
95	* the original e) to nul. */
96	while (e-- > s) {
97	if (!isspace(*e)) {
98	break;
99	}
100	}
101	e[1] = 0;
102
103	/* Next, advance past all leading space and return a ptr to the
104	* first non-space char; possibly the terminating nul. */
105	return skip_whitespace(s);
106	}
107
108
109	#define parse_error(x) { err=x; goto pe_label; }
110
111	/* Don't depend on the tools to combine strings. */
112	static const char config_file[] = CONFIG_FILE;
113
114	/* There are 4 chars + 1 nul for each of user/group/other. */
115	static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
116
117	/* We don't supply a value for the nul, so an index adjustment is
118	* necessary below. Also, we use unsigned short here to save some
119	* space even though these are really mode_t values. */
120	static const unsigned short mode_mask[] = {
121	/* SST sst xxx --- */
122	S_ISUID, S_ISUID\|S_IXUSR, S_IXUSR, 0, /* user */
123	S_ISGID, S_ISGID\|S_IXGRP, S_IXGRP, 0, /* group */
124	0, S_IXOTH, S_IXOTH, 0 /* other */
125	};
126
127	static void parse_config_file(void)
128	{
129	struct BB_suid_config *sct_head;
130	struct BB_suid_config *sct;
131	struct BB_applet *applet;
132	FILE *f;
133	char *err;
134	char *s;
135	char *e;
136	int i, lc, section;
137	char buffer[256];
138	struct stat st;
139
140	assert(!suid_config); /* Should be set to NULL by bss init. */
141
142	if ((stat(config_file, &st) != 0) /* No config file? */
143	\|\| !S_ISREG(st.st_mode) /* Not a regular file? */
144	\|\| (st.st_uid != 0) /* Not owned by root? */
145	\|\| (st.st_mode & (S_IWGRP \| S_IWOTH)) /* Writable by non-root? */
146	\|\| !(f = fopen(config_file, "r")) /* Cannot open? */
147	) {
148	return;
149	}
150
151	suid_cfg_readable = 1;
152	sct_head = NULL;
153	section = lc = 0;
154
155	do {
156	s = buffer;
157
158	if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
159	if (ferror(f)) { /* Make sure it wasn't a read error. */
160	parse_error("reading");
161	}
162	fclose(f);
163	suid_config = sct_head; /* Success, so set the pointer. */
164	return;
165	}
166
167	lc++; /* Got a (partial) line. */
168
169	/* If a line is too long for our buffer, we consider it an error.
170	* The following test does mistreat one corner case though.
171	* If the final line of the file does not end with a newline and
172	* yet exactly fills the buffer, it will be treated as too long
173	* even though there isn't really a problem. But it isn't really
174	* worth adding code to deal with such an unlikely situation, and
175	* we do err on the side of caution. Besides, the line would be
176	* too long if it did end with a newline. */
177	if (!strchr(s, '\n') && !feof(f)) {
178	parse_error("line too long");
179	}
180
181	/* Trim leading and trailing whitespace, ignoring comments, and
182	* check if the resulting string is empty. */
183	if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) {
184	continue;
185	}
186
187	/* Check for a section header. */
188
189	if (*s == '[') {
190	/* Unlike the old code, we ignore leading and trailing
191	* whitespace for the section name. We also require that
192	* there are no stray characters after the closing bracket. */
193	if (!(e = strchr(s, ']')) /* Missing right bracket? */
194	\|\| e[1] /* Trailing characters? */
195	\|\| !(s = get_trimmed_slice(s+1, e)) / Missing name? */
196	) {
197	parse_error("section header");
198	}
199	/* Right now we only have one section so just check it.
200	* If more sections are added in the future, please don't
201	* resort to cascading ifs with multiple strcasecmp calls.
202	* That kind of bloated code is all too common. A loop
203	* and a string table would be a better choice unless the
204	* number of sections is very small. */
205	if (strcasecmp(s, "SUID") == 0) {
206	section = 1;
207	continue;
208	}
209	section = -1; /* Unknown section so set to skip. */
210	continue;
211	}
212
213	/* Process sections. */
214
215	if (section == 1) { /* SUID */
216	/* Since we trimmed leading and trailing space above, we're
217	* now looking for strings of the form
218	* <key>[::space::]=[::space::]<value>
219	* where both key and value could contain inner whitespace. */
220
221	/* First get the key (an applet name in our case). */
222	if (!!(e = strchr(s, '='))) {
223	s = get_trimmed_slice(s, e);
224	}
225	if (!e \|\| !s) { / Missing '=' or empty key. */
226	parse_error("keyword");
227	}
228
229	/* Ok, we have an applet name. Process the rhs if this
230	* applet is currently built in and ignore it otherwise.
231	* Note: This can hide config file bugs which only pop
232	* up when the busybox configuration is changed. */
233	if ((applet = find_applet_by_name(s))) {
234	/* Note: We currently don't check for duplicates!
235	* The last config line for each applet will be the
236	* one used since we insert at the head of the list.
237	* I suppose this could be considered a feature. */
238	sct = xmalloc(sizeof(struct BB_suid_config));
239	sct->m_applet = applet;
240	sct->m_mode = 0;
241	sct->m_next = sct_head;
242	sct_head = sct;
243
244	/* Get the specified mode. */
245
246	e = skip_whitespace(e+1);
247
248	for (i=0 ; i < 3 ; i++) {
249	const char *q;
250	if (!(q = strchrnul(mode_chars + 5i, *e++))) {
251	parse_error("mode");
252	}
253	/* Adjust by -i to account for nul. */
254	sct->m_mode \|= mode_mask[(q - mode_chars) - i];
255	}
256
257	/* Now get the the user/group info. */
258
259	s = skip_whitespace(e);
260
261	/* Note: We require whitespace between the mode and the
262	* user/group info. */
263	if ((s == e) \|\| !(e = strchr(s, '.'))) {
264	parse_error("<uid>.<gid>");
265	}
266	*e++ = 0;
267
268	/* We can't use get_ug_id here since it would exit()
269	* if a uid or gid was not found. Oh well... */
270	{
271	char *e2;
272
273	sct->m_uid = strtoul(s, &e2, 10);
274	if (*e2 \|\| (s == e2)) {
275	struct passwd *pwd = getpwnam(s);
276	if (!pwd) {
277	parse_error("user");
278	}
279	sct->m_uid = pwd->pw_uid;
280	}
281
282	sct->m_gid = strtoul(e, &e2, 10);
283	if (*e2 \|\| (e == e2)) {
284	struct group *grp;
285	if (!(grp = getgrnam(e))) {
286	parse_error("group");
287	}
288	sct->m_gid = grp->gr_gid;
289	}
290	}
291	}
292	continue;
293	}
294
295	/* Unknown sections are ignored. */
296
297	/* Encountering configuration lines prior to seeing a
298	* section header is treated as an error. This is how
299	* the old code worked, but it may not be desirable.
300	* We may want to simply ignore such lines in case they
301	* are used in some future version of busybox. */
302	if (!section) {
303	parse_error("keyword outside section");
304	}
305
306	} while (1);
307
308	pe_label:
309	fprintf(stderr, "Parse error in %s, line %d: %s\n",
310	config_file, lc, err);
311
312	fclose(f);
313	/* Release any allocated memory before returning. */
314	while (sct_head) {
315	sct = sct_head->m_next;
316	free(sct_head);
317	sct_head = sct;
318	}
319	return;
320	}
321
322	#else
323	#define parse_config_file() ((void)0)
324	#endif /* CONFIG_FEATURE_SUID_CONFIG */
325
326	#ifdef CONFIG_FEATURE_SUID
327	static void check_suid(struct BB_applet *applet)
328	{
329	uid_t ruid = getuid(); /* real [ug]id */
330	uid_t rgid = getgid();
331
332	#ifdef CONFIG_FEATURE_SUID_CONFIG
333	if (suid_cfg_readable) {
334	struct BB_suid_config *sct;
335
336	for (sct = suid_config; sct; sct = sct->m_next) {
337	if (sct->m_applet == applet)
338	break;
339	}
340	if (sct) {
341	mode_t m = sct->m_mode;
342
343	if (sct->m_uid == ruid)
344	/* same uid */
345	m >>= 6;
346	else if ((sct->m_gid == rgid) \|\| ingroup(ruid, sct->m_gid))
347	/* same group / in group */
348	m >>= 3;
349
350	if (!(m & S_IXOTH)) /* is x bit not set ? */
351	bb_error_msg_and_die("you have no permission to run this applet!");
352
353	if (sct->m_gid != 0) {
354	/* _both_ have to be set for sgid */
355	if ((sct->m_mode & (S_ISGID \| S_IXGRP)) == (S_ISGID \| S_IXGRP)) {
356	xsetgid(sct->m_gid);
357	} else xsetgid(rgid); /* no sgid -> drop */
358	}
359	if (sct->m_uid != 0) {
360	if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
361	else xsetuid(ruid); /* no suid -> drop */
362	}
363	} else {
364	/* default: drop all privileges */
365	xsetgid(rgid);
366	xsetuid(ruid);
367	}
368	return;
369	} else {
370	#ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
371	static int onetime = 0;
372
373	if (!onetime) {
374	onetime = 1;
375	fprintf(stderr, "Using fallback suid method\n");
376	}
377	#endif
378	}
379	#endif
380
381	if (applet->need_suid == _BB_SUID_ALWAYS) {
382	if (geteuid()) bb_error_msg_and_die("applet requires root privileges!");
383	} else if (applet->need_suid == _BB_SUID_NEVER) {
384	xsetgid(rgid); /* drop all privileges */
385	xsetuid(ruid);
386	}
387	}
388	#else
389	#define check_suid(x)
390	#endif /* CONFIG_FEATURE_SUID */
391
392
393
394	#ifdef CONFIG_FEATURE_COMPRESS_USAGE
395
396	#include "usage_compressed.h"
397	#include "unarchive.h"
398
399	static const char *unpack_usage_messages(void)
400	{
401	int input[2], output[2], pid;
402	char *buf;
403
404	if(pipe(input) < 0 \|\| pipe(output) < 0)
405	exit(1);
406
407	pid = fork();
408	switch (pid) {
409	case -1: /* error */
410	exit(1);
411	case 0: /* child */
412	close(input[1]);
413	close(output[0]);
414	uncompressStream(input[0], output[1]);
415	exit(0);
416	}
417	/* parent */
418
419	close(input[0]);
420	close(output[1]);
421	pid = fork();
422	switch (pid) {
423	case -1: /* error */
424	exit(1);
425	case 0: /* child */
426	full_write(input[1], packed_usage, sizeof(packed_usage));
427	exit(0);
428	}
429	/* parent */
430	close(input[1]);
431
432	buf = xmalloc(SIZEOF_usage_messages);
433	full_read(output[0], buf, SIZEOF_usage_messages);
434	return buf;
435	}
436
437	#else
438	#define unpack_usage_messages() usage_messages
439	#endif /* ENABLE_FEATURE_COMPRESS_USAGE */
440
441	void bb_show_usage(void)
442	{
443	if (ENABLE_SHOW_USAGE) {
444	const char *format_string;
445	const char *usage_string = unpack_usage_messages();
446	int i;
447
448	for (i = applet_using - applets; i > 0;)
449	if (!*usage_string++) --i;
450
451	format_string = "%s\n\nUsage: %s %s\n\n";
452	if (*usage_string == '\b')
453	format_string = "%s\n\nNo help available.\n\n";
454	fprintf(stderr, format_string, bb_msg_full_version,
455	applet_using->name, usage_string);
456	}
457
458	exit(xfunc_error_retval);
459	}
460
461	static int applet_name_compare(const void name, const void vapplet)
462	{
463	const struct BB_applet *applet = vapplet;
464
465	return strcmp(name, applet->name);
466	}
467
468	struct BB_applet find_applet_by_name(const char name)
469	{
470	return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
471	applet_name_compare);
472	}
473
474	void run_applet_by_name(const char name, int argc, char *argv)
475	{
476	if (ENABLE_FEATURE_SUID_CONFIG)
477	parse_config_file();
478
479	if (!strncmp(name, "busybox", 7))
480	exit(busybox_main(argc, argv));
481	/* Do a binary search to find the applet entry given the name. */
482	applet_using = find_applet_by_name(name);
483	if (applet_using) {
484	applet_name = applet_using->name;
485	if (argc == 2 && !strcmp(argv[1], "--help"))
486	bb_show_usage();
487	if (ENABLE_FEATURE_SUID)
488	check_suid(applet_using);
489	exit(applet_using->main(argc, argv));
490	}
491	}