busybox/libbb/xfuncs_printf.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 * Copyright (C) 2006 Rob Landley
 * Copyright (C) 2006 Denys Vlasenko
 *
 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
 */

/* We need to have separate xfuncs.c and xfuncs_printf.c because
 * with current linkers, even with section garbage collection,
 * if *.o module references any of XXXprintf functions, you pull in
 * entire printf machinery. Even if you do not use the function
 * which uses XXXprintf.
 *
 * xfuncs.c contains functions (not necessarily xfuncs)
 * which do not pull in printf, directly or indirectly.
 * xfunc_printf.c contains those which do.
 */

#include "libbb.h"


/* All the functions starting with "x" call bb_error_msg_and_die() if they
 * fail, so callers never need to check for errors.  If it returned, it
 * succeeded. */

#ifndef DMALLOC
/* dmalloc provides variants of these that do abort() on failure.
 * Since dmalloc's prototypes overwrite the impls here as they are
 * included after these prototypes in libbb.h, all is well.
 */
// Warn if we can't allocate size bytes of memory.
void* FAST_FUNC malloc_or_warn(size_t size)
{
	void *ptr = malloc(size);
	if (ptr == NULL && size != 0)
		bb_error_msg(bb_msg_memory_exhausted);
	return ptr;
}

// Die if we can't allocate size bytes of memory.
void* FAST_FUNC xmalloc(size_t size)
{
	void *ptr = malloc(size);
	if (ptr == NULL && size != 0)
		bb_error_msg_and_die(bb_msg_memory_exhausted);
	return ptr;
}

// Die if we can't resize previously allocated memory.  (This returns a pointer
// to the new memory, which may or may not be the same as the old memory.
// It'll copy the contents to a new chunk and free the old one if necessary.)
void* FAST_FUNC xrealloc(void *ptr, size_t size)
{
	ptr = realloc(ptr, size);
	if (ptr == NULL && size != 0)
		bb_error_msg_and_die(bb_msg_memory_exhausted);
	return ptr;
}
#endif /* DMALLOC */

// Die if we can't allocate and zero size bytes of memory.
void* FAST_FUNC xzalloc(size_t size)
{
	void *ptr = xmalloc(size);
	memset(ptr, 0, size);
	return ptr;
}

// Die if we can't copy a string to freshly allocated memory.
char* FAST_FUNC xstrdup(const char *s)
{
	char *t;

	if (s == NULL)
		return NULL;

	t = strdup(s);

	if (t == NULL)
		bb_error_msg_and_die(bb_msg_memory_exhausted);

	return t;
}

// Die if we can't allocate n+1 bytes (space for the null terminator) and copy
// the (possibly truncated to length n) string into it.
char* FAST_FUNC xstrndup(const char *s, int n)
{
	int m;
	char *t;

	if (ENABLE_DEBUG && s == NULL)
		bb_error_msg_and_die("xstrndup bug");

	/* We can just xmalloc(n+1) and strncpy into it, */
	/* but think about xstrndup("abc", 10000) wastage! */
	m = n;
	t = (char*) s;
	while (m) {
		if (!*t) break;
		m--;
		t++;
	}
	n -= m;
	t = xmalloc(n + 1);
	t[n] = '\0';

	return memcpy(t, s, n);
}

// Die if we can't open a file and return a FILE* to it.
// Notice we haven't got xfread(), This is for use with fscanf() and friends.
FILE* FAST_FUNC xfopen(const char *path, const char *mode)
{
	FILE *fp = fopen(path, mode);
	if (fp == NULL)
		bb_perror_msg_and_die("can't open '%s'", path);
	return fp;
}

// Die if we can't open a file and return a fd.
int FAST_FUNC xopen3(const char *pathname, int flags, int mode)
{
	int ret;

	ret = open(pathname, flags, mode);
	if (ret < 0) {
		bb_perror_msg_and_die("can't open '%s'", pathname);
	}
	return ret;
}

// Die if we can't open an existing file and return a fd.
int FAST_FUNC xopen(const char *pathname, int flags)
{
	return xopen3(pathname, flags, 0666);
}

// Warn if we can't open a file and return a fd.
int FAST_FUNC open3_or_warn(const char *pathname, int flags, int mode)
{
	int ret;

	ret = open(pathname, flags, mode);
	if (ret < 0) {
		bb_perror_msg("can't open '%s'", pathname);
	}
	return ret;
}

// Warn if we can't open a file and return a fd.
int FAST_FUNC open_or_warn(const char *pathname, int flags)
{
	return open3_or_warn(pathname, flags, 0666);
}

void FAST_FUNC xunlink(const char *pathname)
{
	if (unlink(pathname))
		bb_perror_msg_and_die("can't remove file '%s'", pathname);
}

void FAST_FUNC xrename(const char *oldpath, const char *newpath)
{
	if (rename(oldpath, newpath))
		bb_perror_msg_and_die("can't move '%s' to '%s'", oldpath, newpath);
}

int FAST_FUNC rename_or_warn(const char *oldpath, const char *newpath)
{
	int n = rename(oldpath, newpath);
	if (n)
		bb_perror_msg("can't move '%s' to '%s'", oldpath, newpath);
	return n;
}

void FAST_FUNC xpipe(int filedes[2])
{
	if (pipe(filedes))
		bb_perror_msg_and_die("can't create pipe");
}

void FAST_FUNC xdup2(int from, int to)
{
	if (dup2(from, to) != to)
		bb_perror_msg_and_die("can't duplicate file descriptor");
}

// "Renumber" opened fd
void FAST_FUNC xmove_fd(int from, int to)
{
	if (from == to)
		return;
	xdup2(from, to);
	close(from);
}

// Die with an error message if we can't write the entire buffer.
void FAST_FUNC xwrite(int fd, const void *buf, size_t count)
{
	if (count) {
		ssize_t size = full_write(fd, buf, count);
		if ((size_t)size != count)
			bb_error_msg_and_die("short write");
	}
}

// Die with an error message if we can't lseek to the right spot.
off_t FAST_FUNC xlseek(int fd, off_t offset, int whence)
{
	off_t off = lseek(fd, offset, whence);
	if (off == (off_t)-1) {
		if (whence == SEEK_SET)
			bb_perror_msg_and_die("lseek(%"OFF_FMT"u)", offset);
		bb_perror_msg_and_die("lseek");
	}
	return off;
}

// Die with supplied filename if this FILE* has ferror set.
void FAST_FUNC die_if_ferror(FILE *fp, const char *fn)
{
	if (ferror(fp)) {
		/* ferror doesn't set useful errno */
		bb_error_msg_and_die("%s: I/O error", fn);
	}
}

// Die with an error message if stdout has ferror set.
void FAST_FUNC die_if_ferror_stdout(void)
{
	die_if_ferror(stdout, bb_msg_standard_output);
}

// Die with an error message if we have trouble flushing stdout.
void FAST_FUNC xfflush_stdout(void)
{
	if (fflush(stdout)) {
		bb_perror_msg_and_die(bb_msg_standard_output);
	}
}


int FAST_FUNC bb_putchar(int ch)
{
	/* time.c needs putc(ch, stdout), not putchar(ch).
	 * it does "stdout = stderr;", but then glibc's putchar()
	 * doesn't work as expected. bad glibc, bad */
	return putc(ch, stdout);
}

/* Die with an error message if we can't copy an entire FILE* to stdout,
 * then close that file. */
void FAST_FUNC xprint_and_close_file(FILE *file)
{
	fflush(stdout);
	// copyfd outputs error messages for us.
	if (bb_copyfd_eof(fileno(file), 1) == -1)
		xfunc_die();

	fclose(file);
}

// Die with an error message if we can't malloc() enough space and do an
// sprintf() into that space.
char* FAST_FUNC xasprintf(const char *format, ...)
{
	va_list p;
	int r;
	char *string_ptr;

#if 1
	// GNU extension
	va_start(p, format);
	r = vasprintf(&string_ptr, format, p);
	va_end(p);
#else
	// Bloat for systems that haven't got the GNU extension.
	va_start(p, format);
	r = vsnprintf(NULL, 0, format, p);
	va_end(p);
	string_ptr = xmalloc(r+1);
	va_start(p, format);
	r = vsnprintf(string_ptr, r+1, format, p);
	va_end(p);
#endif

	if (r < 0)
		bb_error_msg_and_die(bb_msg_memory_exhausted);
	return string_ptr;
}

#if 0 /* If we will ever meet a libc which hasn't [f]dprintf... */
int FAST_FUNC fdprintf(int fd, const char *format, ...)
{
	va_list p;
	int r;
	char *string_ptr;

#if 1
	// GNU extension
	va_start(p, format);
	r = vasprintf(&string_ptr, format, p);
	va_end(p);
#else
	// Bloat for systems that haven't got the GNU extension.
	va_start(p, format);
	r = vsnprintf(NULL, 0, format, p) + 1;
	va_end(p);
	string_ptr = malloc(r);
	if (string_ptr) {
		va_start(p, format);
		r = vsnprintf(string_ptr, r, format, p);
		va_end(p);
	}
#endif

	if (r >= 0) {
		full_write(fd, string_ptr, r);
		free(string_ptr);
	}
	return r;
}
#endif

void FAST_FUNC xsetenv(const char *key, const char *value)
{
	if (setenv(key, value, 1))
		bb_error_msg_and_die(bb_msg_memory_exhausted);
}

// Die with an error message if we can't set gid.  (Because resource limits may
// limit this user to a given number of processes, and if that fills up the
// setgid() will fail and we'll _still_be_root_, which is bad.)
void FAST_FUNC xsetgid(gid_t gid)
{
	if (setgid(gid)) bb_perror_msg_and_die("setgid");
}

// Die with an error message if we can't set uid.  (See xsetgid() for why.)
void FAST_FUNC xsetuid(uid_t uid)
{
	if (setuid(uid)) bb_perror_msg_and_die("setuid");
}

// Die if we can't chdir to a new path.
void FAST_FUNC xchdir(const char *path)
{
	if (chdir(path))
		bb_perror_msg_and_die("chdir(%s)", path);
}

void FAST_FUNC xchroot(const char *path)
{
	if (chroot(path))
		bb_perror_msg_and_die("can't change root directory to %s", path);
}

// Print a warning message if opendir() fails, but don't die.
DIR* FAST_FUNC warn_opendir(const char *path)
{
	DIR *dp;

	dp = opendir(path);
	if (!dp)
		bb_perror_msg("can't open '%s'", path);
	return dp;
}

// Die with an error message if opendir() fails.
DIR* FAST_FUNC xopendir(const char *path)
{
	DIR *dp;

	dp = opendir(path);
	if (!dp)
		bb_perror_msg_and_die("can't open '%s'", path);
	return dp;
}

// Die with an error message if we can't open a new socket.
int FAST_FUNC xsocket(int domain, int type, int protocol)
{
	int r = socket(domain, type, protocol);

	if (r < 0) {
		/* Hijack vaguely related config option */
#if ENABLE_VERBOSE_RESOLUTION_ERRORS
		const char *s = "INET";
		if (domain == AF_PACKET) s = "PACKET";
		if (domain == AF_NETLINK) s = "NETLINK";
USE_FEATURE_IPV6(if (domain == AF_INET6) s = "INET6";)
		bb_perror_msg_and_die("socket(AF_%s)", s);
#else
		bb_perror_msg_and_die("socket");
#endif
	}

	return r;
}

// Die with an error message if we can't bind a socket to an address.
void FAST_FUNC xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
{
	if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
}

// Die with an error message if we can't listen for connections on a socket.
void FAST_FUNC xlisten(int s, int backlog)
{
	if (listen(s, backlog)) bb_perror_msg_and_die("listen");
}

/* Die with an error message if sendto failed.
 * Return bytes sent otherwise  */
ssize_t FAST_FUNC xsendto(int s, const  void *buf, size_t len, const struct sockaddr *to,
				socklen_t tolen)
{
	ssize_t ret = sendto(s, buf, len, 0, to, tolen);
	if (ret < 0) {
		if (ENABLE_FEATURE_CLEAN_UP)
			close(s);
		bb_perror_msg_and_die("sendto");
	}
	return ret;
}

// xstat() - a stat() which dies on failure with meaningful error message
void FAST_FUNC xstat(const char *name, struct stat *stat_buf)
{
	if (stat(name, stat_buf))
		bb_perror_msg_and_die("can't stat '%s'", name);
}

// selinux_or_die() - die if SELinux is disabled.
void FAST_FUNC selinux_or_die(void)
{
#if ENABLE_SELINUX
	int rc = is_selinux_enabled();
	if (rc == 0) {
		bb_error_msg_and_die("SELinux is disabled");
	} else if (rc < 0) {
		bb_error_msg_and_die("is_selinux_enabled() failed");
	}
#else
	bb_error_msg_and_die("SELinux support is disabled");
#endif
}

int FAST_FUNC ioctl_or_perror_and_die(int fd, unsigned request, void *argp, const char *fmt,...)
{
	int ret;
	va_list p;

	ret = ioctl(fd, request, argp);
	if (ret < 0) {
		va_start(p, fmt);
		bb_verror_msg(fmt, p, strerror(errno));
		/* xfunc_die can actually longjmp, so be nice */
		va_end(p);
		xfunc_die();
	}
	return ret;
}

int FAST_FUNC ioctl_or_perror(int fd, unsigned request, void *argp, const char *fmt,...)
{
	va_list p;
	int ret = ioctl(fd, request, argp);

	if (ret < 0) {
		va_start(p, fmt);
		bb_verror_msg(fmt, p, strerror(errno));
		va_end(p);
	}
	return ret;
}

#if ENABLE_IOCTL_HEX2STR_ERROR
int FAST_FUNC bb_ioctl_or_warn(int fd, unsigned request, void *argp, const char *ioctl_name)
{
	int ret;

	ret = ioctl(fd, request, argp);
	if (ret < 0)
		bb_simple_perror_msg(ioctl_name);
	return ret;
}
int FAST_FUNC bb_xioctl(int fd, unsigned request, void *argp, const char *ioctl_name)
{
	int ret;

	ret = ioctl(fd, request, argp);
	if (ret < 0)
		bb_simple_perror_msg_and_die(ioctl_name);
	return ret;
}
#else
int FAST_FUNC bb_ioctl_or_warn(int fd, unsigned request, void *argp)
{
	int ret;

	ret = ioctl(fd, request, argp);
	if (ret < 0)
		bb_perror_msg("ioctl %#x failed", request);
	return ret;
}
int FAST_FUNC bb_xioctl(int fd, unsigned request, void *argp)
{
	int ret;

	ret = ioctl(fd, request, argp);
	if (ret < 0)
		bb_perror_msg_and_die("ioctl %#x failed", request);
	return ret;
}
#endif
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Utility routines.
4	*
5	* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6	* Copyright (C) 2006 Rob Landley
7	* Copyright (C) 2006 Denys Vlasenko
8	*
9	* Licensed under GPL version 2, see file LICENSE in this tarball for details.
10	*/
11
12	/* We need to have separate xfuncs.c and xfuncs_printf.c because
13	* with current linkers, even with section garbage collection,
14	* if *.o module references any of XXXprintf functions, you pull in
15	* entire printf machinery. Even if you do not use the function
16	* which uses XXXprintf.
17	*
18	* xfuncs.c contains functions (not necessarily xfuncs)
19	* which do not pull in printf, directly or indirectly.
20	* xfunc_printf.c contains those which do.
21	*/
22
23	#include "libbb.h"
24
25
26	/* All the functions starting with "x" call bb_error_msg_and_die() if they
27	* fail, so callers never need to check for errors. If it returned, it
28	* succeeded. */
29
30	#ifndef DMALLOC
31	/* dmalloc provides variants of these that do abort() on failure.
32	* Since dmalloc's prototypes overwrite the impls here as they are
33	* included after these prototypes in libbb.h, all is well.
34	*/
35	// Warn if we can't allocate size bytes of memory.
36	void* FAST_FUNC malloc_or_warn(size_t size)
37	{
38	void *ptr = malloc(size);
39	if (ptr == NULL && size != 0)
40	bb_error_msg(bb_msg_memory_exhausted);
41	return ptr;
42	}
43
44	// Die if we can't allocate size bytes of memory.
45	void* FAST_FUNC xmalloc(size_t size)
46	{
47	void *ptr = malloc(size);
48	if (ptr == NULL && size != 0)
49	bb_error_msg_and_die(bb_msg_memory_exhausted);
50	return ptr;
51	}
52
53	// Die if we can't resize previously allocated memory. (This returns a pointer
54	// to the new memory, which may or may not be the same as the old memory.
55	// It'll copy the contents to a new chunk and free the old one if necessary.)
56	void* FAST_FUNC xrealloc(void *ptr, size_t size)
57	{
58	ptr = realloc(ptr, size);
59	if (ptr == NULL && size != 0)
60	bb_error_msg_and_die(bb_msg_memory_exhausted);
61	return ptr;
62	}
63	#endif /* DMALLOC */
64
65	// Die if we can't allocate and zero size bytes of memory.
66	void* FAST_FUNC xzalloc(size_t size)
67	{
68	void *ptr = xmalloc(size);
69	memset(ptr, 0, size);
70	return ptr;
71	}
72
73	// Die if we can't copy a string to freshly allocated memory.
74	char* FAST_FUNC xstrdup(const char *s)
75	{
76	char *t;
77
78	if (s == NULL)
79	return NULL;
80
81	t = strdup(s);
82
83	if (t == NULL)
84	bb_error_msg_and_die(bb_msg_memory_exhausted);
85
86	return t;
87	}
88
89	// Die if we can't allocate n+1 bytes (space for the null terminator) and copy
90	// the (possibly truncated to length n) string into it.
91	char* FAST_FUNC xstrndup(const char *s, int n)
92	{
93	int m;
94	char *t;
95
96	if (ENABLE_DEBUG && s == NULL)
97	bb_error_msg_and_die("xstrndup bug");
98
99	/* We can just xmalloc(n+1) and strncpy into it, */
100	/* but think about xstrndup("abc", 10000) wastage! */
101	m = n;
102	t = (char*) s;
103	while (m) {
104	if (!*t) break;
105	m--;
106	t++;
107	}
108	n -= m;
109	t = xmalloc(n + 1);
110	t[n] = '\0';
111
112	return memcpy(t, s, n);
113	}
114
115	// Die if we can't open a file and return a FILE* to it.
116	// Notice we haven't got xfread(), This is for use with fscanf() and friends.
117	FILE* FAST_FUNC xfopen(const char path, const char mode)
118	{
119	FILE *fp = fopen(path, mode);
120	if (fp == NULL)
121	bb_perror_msg_and_die("can't open '%s'", path);
122	return fp;
123	}
124
125	// Die if we can't open a file and return a fd.
126	int FAST_FUNC xopen3(const char *pathname, int flags, int mode)
127	{
128	int ret;
129
130	ret = open(pathname, flags, mode);
131	if (ret < 0) {
132	bb_perror_msg_and_die("can't open '%s'", pathname);
133	}
134	return ret;
135	}
136
137	// Die if we can't open an existing file and return a fd.
138	int FAST_FUNC xopen(const char *pathname, int flags)
139	{
140	return xopen3(pathname, flags, 0666);
141	}
142
143	// Warn if we can't open a file and return a fd.
144	int FAST_FUNC open3_or_warn(const char *pathname, int flags, int mode)
145	{
146	int ret;
147
148	ret = open(pathname, flags, mode);
149	if (ret < 0) {
150	bb_perror_msg("can't open '%s'", pathname);
151	}
152	return ret;
153	}
154
155	// Warn if we can't open a file and return a fd.
156	int FAST_FUNC open_or_warn(const char *pathname, int flags)
157	{
158	return open3_or_warn(pathname, flags, 0666);
159	}
160
161	void FAST_FUNC xunlink(const char *pathname)
162	{
163	if (unlink(pathname))
164	bb_perror_msg_and_die("can't remove file '%s'", pathname);
165	}
166
167	void FAST_FUNC xrename(const char oldpath, const char newpath)
168	{
169	if (rename(oldpath, newpath))
170	bb_perror_msg_and_die("can't move '%s' to '%s'", oldpath, newpath);
171	}
172
173	int FAST_FUNC rename_or_warn(const char oldpath, const char newpath)
174	{
175	int n = rename(oldpath, newpath);
176	if (n)
177	bb_perror_msg("can't move '%s' to '%s'", oldpath, newpath);
178	return n;
179	}
180
181	void FAST_FUNC xpipe(int filedes[2])
182	{
183	if (pipe(filedes))
184	bb_perror_msg_and_die("can't create pipe");
185	}
186
187	void FAST_FUNC xdup2(int from, int to)
188	{
189	if (dup2(from, to) != to)
190	bb_perror_msg_and_die("can't duplicate file descriptor");
191	}
192
193	// "Renumber" opened fd
194	void FAST_FUNC xmove_fd(int from, int to)
195	{
196	if (from == to)
197	return;
198	xdup2(from, to);
199	close(from);
200	}
201
202	// Die with an error message if we can't write the entire buffer.
203	void FAST_FUNC xwrite(int fd, const void *buf, size_t count)
204	{
205	if (count) {
206	ssize_t size = full_write(fd, buf, count);
207	if ((size_t)size != count)
208	bb_error_msg_and_die("short write");
209	}
210	}
211
212	// Die with an error message if we can't lseek to the right spot.
213	off_t FAST_FUNC xlseek(int fd, off_t offset, int whence)
214	{
215	off_t off = lseek(fd, offset, whence);
216	if (off == (off_t)-1) {
217	if (whence == SEEK_SET)
218	bb_perror_msg_and_die("lseek(%"OFF_FMT"u)", offset);
219	bb_perror_msg_and_die("lseek");
220	}
221	return off;
222	}
223
224	// Die with supplied filename if this FILE* has ferror set.
225	void FAST_FUNC die_if_ferror(FILE fp, const char fn)
226	{
227	if (ferror(fp)) {
228	/* ferror doesn't set useful errno */
229	bb_error_msg_and_die("%s: I/O error", fn);
230	}
231	}
232
233	// Die with an error message if stdout has ferror set.
234	void FAST_FUNC die_if_ferror_stdout(void)
235	{
236	die_if_ferror(stdout, bb_msg_standard_output);
237	}
238
239	// Die with an error message if we have trouble flushing stdout.
240	void FAST_FUNC xfflush_stdout(void)
241	{
242	if (fflush(stdout)) {
243	bb_perror_msg_and_die(bb_msg_standard_output);
244	}
245	}
246
247
248	int FAST_FUNC bb_putchar(int ch)
249	{
250	/* time.c needs putc(ch, stdout), not putchar(ch).
251	* it does "stdout = stderr;", but then glibc's putchar()
252	* doesn't work as expected. bad glibc, bad */
253	return putc(ch, stdout);
254	}
255
256	/* Die with an error message if we can't copy an entire FILE* to stdout,
257	* then close that file. */
258	void FAST_FUNC xprint_and_close_file(FILE *file)
259	{
260	fflush(stdout);
261	// copyfd outputs error messages for us.
262	if (bb_copyfd_eof(fileno(file), 1) == -1)
263	xfunc_die();
264
265	fclose(file);
266	}
267
268	// Die with an error message if we can't malloc() enough space and do an
269	// sprintf() into that space.
270	char* FAST_FUNC xasprintf(const char *format, ...)
271	{
272	va_list p;
273	int r;
274	char *string_ptr;
275
276	#if 1
277	// GNU extension
278	va_start(p, format);
279	r = vasprintf(&string_ptr, format, p);
280	va_end(p);
281	#else
282	// Bloat for systems that haven't got the GNU extension.
283	va_start(p, format);
284	r = vsnprintf(NULL, 0, format, p);
285	va_end(p);
286	string_ptr = xmalloc(r+1);
287	va_start(p, format);
288	r = vsnprintf(string_ptr, r+1, format, p);
289	va_end(p);
290	#endif
291
292	if (r < 0)
293	bb_error_msg_and_die(bb_msg_memory_exhausted);
294	return string_ptr;
295	}
296
297	#if 0 /* If we will ever meet a libc which hasn't [f]dprintf... */
298	int FAST_FUNC fdprintf(int fd, const char *format, ...)
299	{
300	va_list p;
301	int r;
302	char *string_ptr;
303
304	#if 1
305	// GNU extension
306	va_start(p, format);
307	r = vasprintf(&string_ptr, format, p);
308	va_end(p);
309	#else
310	// Bloat for systems that haven't got the GNU extension.
311	va_start(p, format);
312	r = vsnprintf(NULL, 0, format, p) + 1;
313	va_end(p);
314	string_ptr = malloc(r);
315	if (string_ptr) {
316	va_start(p, format);
317	r = vsnprintf(string_ptr, r, format, p);
318	va_end(p);
319	}
320	#endif
321
322	if (r >= 0) {
323	full_write(fd, string_ptr, r);
324	free(string_ptr);
325	}
326	return r;
327	}
328	#endif
329
330	void FAST_FUNC xsetenv(const char key, const char value)
331	{
332	if (setenv(key, value, 1))
333	bb_error_msg_and_die(bb_msg_memory_exhausted);
334	}
335
336	// Die with an error message if we can't set gid. (Because resource limits may
337	// limit this user to a given number of processes, and if that fills up the
338	// setgid() will fail and we'll _still_be_root_, which is bad.)
339	void FAST_FUNC xsetgid(gid_t gid)
340	{
341	if (setgid(gid)) bb_perror_msg_and_die("setgid");
342	}
343
344	// Die with an error message if we can't set uid. (See xsetgid() for why.)
345	void FAST_FUNC xsetuid(uid_t uid)
346	{
347	if (setuid(uid)) bb_perror_msg_and_die("setuid");
348	}
349
350	// Die if we can't chdir to a new path.
351	void FAST_FUNC xchdir(const char *path)
352	{
353	if (chdir(path))
354	bb_perror_msg_and_die("chdir(%s)", path);
355	}
356
357	void FAST_FUNC xchroot(const char *path)
358	{
359	if (chroot(path))
360	bb_perror_msg_and_die("can't change root directory to %s", path);
361	}
362
363	// Print a warning message if opendir() fails, but don't die.
364	DIR* FAST_FUNC warn_opendir(const char *path)
365	{
366	DIR *dp;
367
368	dp = opendir(path);
369	if (!dp)
370	bb_perror_msg("can't open '%s'", path);
371	return dp;
372	}
373
374	// Die with an error message if opendir() fails.
375	DIR* FAST_FUNC xopendir(const char *path)
376	{
377	DIR *dp;
378
379	dp = opendir(path);
380	if (!dp)
381	bb_perror_msg_and_die("can't open '%s'", path);
382	return dp;
383	}
384
385	// Die with an error message if we can't open a new socket.
386	int FAST_FUNC xsocket(int domain, int type, int protocol)
387	{
388	int r = socket(domain, type, protocol);
389
390	if (r < 0) {
391	/* Hijack vaguely related config option */
392	#if ENABLE_VERBOSE_RESOLUTION_ERRORS
393	const char *s = "INET";
394	if (domain == AF_PACKET) s = "PACKET";
395	if (domain == AF_NETLINK) s = "NETLINK";
396	USE_FEATURE_IPV6(if (domain == AF_INET6) s = "INET6";)
397	bb_perror_msg_and_die("socket(AF_%s)", s);
398	#else
399	bb_perror_msg_and_die("socket");
400	#endif
401	}
402
403	return r;
404	}
405
406	// Die with an error message if we can't bind a socket to an address.
407	void FAST_FUNC xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
408	{
409	if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
410	}
411
412	// Die with an error message if we can't listen for connections on a socket.
413	void FAST_FUNC xlisten(int s, int backlog)
414	{
415	if (listen(s, backlog)) bb_perror_msg_and_die("listen");
416	}
417
418	/* Die with an error message if sendto failed.
419	* Return bytes sent otherwise */
420	ssize_t FAST_FUNC xsendto(int s, const void buf, size_t len, const struct sockaddr to,
421	socklen_t tolen)
422	{
423	ssize_t ret = sendto(s, buf, len, 0, to, tolen);
424	if (ret < 0) {
425	if (ENABLE_FEATURE_CLEAN_UP)
426	close(s);
427	bb_perror_msg_and_die("sendto");
428	}
429	return ret;
430	}
431
432	// xstat() - a stat() which dies on failure with meaningful error message
433	void FAST_FUNC xstat(const char name, struct stat stat_buf)
434	{
435	if (stat(name, stat_buf))
436	bb_perror_msg_and_die("can't stat '%s'", name);
437	}
438
439	// selinux_or_die() - die if SELinux is disabled.
440	void FAST_FUNC selinux_or_die(void)
441	{
442	#if ENABLE_SELINUX
443	int rc = is_selinux_enabled();
444	if (rc == 0) {
445	bb_error_msg_and_die("SELinux is disabled");
446	} else if (rc < 0) {
447	bb_error_msg_and_die("is_selinux_enabled() failed");
448	}
449	#else
450	bb_error_msg_and_die("SELinux support is disabled");
451	#endif
452	}
453
454	int FAST_FUNC ioctl_or_perror_and_die(int fd, unsigned request, void argp, const char fmt,...)
455	{
456	int ret;
457	va_list p;
458
459	ret = ioctl(fd, request, argp);
460	if (ret < 0) {
461	va_start(p, fmt);
462	bb_verror_msg(fmt, p, strerror(errno));
463	/* xfunc_die can actually longjmp, so be nice */
464	va_end(p);
465	xfunc_die();
466	}
467	return ret;
468	}
469
470	int FAST_FUNC ioctl_or_perror(int fd, unsigned request, void argp, const char fmt,...)
471	{
472	va_list p;
473	int ret = ioctl(fd, request, argp);
474
475	if (ret < 0) {
476	va_start(p, fmt);
477	bb_verror_msg(fmt, p, strerror(errno));
478	va_end(p);
479	}
480	return ret;
481	}
482
483	#if ENABLE_IOCTL_HEX2STR_ERROR
484	int FAST_FUNC bb_ioctl_or_warn(int fd, unsigned request, void argp, const char ioctl_name)
485	{
486	int ret;
487
488	ret = ioctl(fd, request, argp);
489	if (ret < 0)
490	bb_simple_perror_msg(ioctl_name);
491	return ret;
492	}
493	int FAST_FUNC bb_xioctl(int fd, unsigned request, void argp, const char ioctl_name)
494	{
495	int ret;
496
497	ret = ioctl(fd, request, argp);
498	if (ret < 0)
499	bb_simple_perror_msg_and_die(ioctl_name);
500	return ret;
501	}
502	#else
503	int FAST_FUNC bb_ioctl_or_warn(int fd, unsigned request, void *argp)
504	{
505	int ret;
506
507	ret = ioctl(fd, request, argp);
508	if (ret < 0)
509	bb_perror_msg("ioctl %#x failed", request);
510	return ret;
511	}
512	int FAST_FUNC bb_xioctl(int fd, unsigned request, void *argp)
513	{
514	int ret;
515
516	ret = ioctl(fd, request, argp);
517	if (ret < 0)
518	bb_perror_msg_and_die("ioctl %#x failed", request);
519	return ret;
520	}
521	#endif