busybox/libbb/xfuncs.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 Denis Vlasenko
 *
 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
 */

#include "busybox.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.
 */
// Die if we can't allocate size bytes of memory.
void *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 *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 *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 * 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 * 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 *xfopen(const char *path, const char *mode)
{
	FILE *fp = fopen(path, mode);
	if (fp == NULL)
		bb_perror_msg_and_die("%s", path);
	return fp;
}

// Die if we can't open an existing file and return an fd.
int xopen(const char *pathname, int flags)
{
	//if (ENABLE_DEBUG && (flags & O_CREAT))
	//	bb_error_msg_and_die("xopen() with O_CREAT");

	return xopen3(pathname, flags, 0666);
}

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

	ret = open(pathname, flags, mode);
	if (ret < 0) {
		bb_perror_msg_and_die("%s", pathname);
	}
	return ret;
}

// Turn on nonblocking I/O on a fd
int ndelay_on(int fd)
{
	return fcntl(fd,F_SETFL,fcntl(fd,F_GETFL,0) | O_NONBLOCK);
}

int ndelay_off(int fd)
{
	return fcntl(fd,F_SETFL,fcntl(fd,F_GETFL,0) & ~O_NONBLOCK);
}

// Die with an error message if we can't write the entire buffer.
void xwrite(int fd, const void *buf, size_t count)
{
	if (count) {
		ssize_t size = full_write(fd, buf, count);
		if (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 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 die_if_ferror(FILE *fp, const char *fn)
{
	if (ferror(fp)) {
		bb_error_msg_and_die("%s: I/O error", fn);
	}
}

// Die with an error message if stdout has ferror set.
void 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 xfflush_stdout(void)
{
	if (fflush(stdout)) {
		bb_perror_msg_and_die(bb_msg_standard_output);
	}
}

// This does a fork/exec in one call, using vfork().  Return PID of new child,
// -1 for failure.  Runs argv[0], searching path if that has no / in it.
pid_t spawn(char **argv)
{
	/* Why static? */
	static int failed;
	pid_t pid;
	void *app = ENABLE_FEATURE_SH_STANDALONE_SHELL ? find_applet_by_name(argv[0]) : 0;

	// Be nice to nommu machines.
	failed = 0;
	pid = vfork();
	if (pid < 0) return pid;
	if (!pid) {
		execvp(app ? CONFIG_BUSYBOX_EXEC_PATH : *argv, argv);

		// We're sharing a stack with blocked parent, let parent know we failed
		// and then exit to unblock parent (but don't run atexit() stuff, which
		// would screw up parent.)

		failed = errno;
		_exit(0);
	}
	if (failed) {
		errno = failed;
		return -1;
	}
	return pid;
}

// Die with an error message if we can't spawn a child process.
pid_t xspawn(char **argv)
{
	pid_t pid = spawn(argv);
	if (pid < 0) bb_perror_msg_and_die("%s", *argv);
	return pid;
}

// Wait for the specified child PID to exit, returning child's error return.
int wait4pid(int pid)
{
	int status;

	if (pid == -1 || waitpid(pid, &status, 0) == -1) return -1;
	if (WIFEXITED(status)) return WEXITSTATUS(status);
	if (WIFSIGNALED(status)) return WTERMSIG(status);
	return 0;
}

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

// Converts unsigned long long value into compact 4-char
// representation. Examples: "1234", "1.2k", " 27M", "123T"
// Fifth char is always '\0'
void smart_ulltoa5(unsigned long long ul, char buf[5])
{
	char *fmt;
	char c;
	unsigned v,idx = 0;
	ul *= 10;
	if (ul > 9999*10) { // do not scale if 9999 or less
		while (ul >= 10000) {
			ul /= 1024;
			idx++;
		}
	}
	v = ul; // ullong divisions are expensive, avoid them

	fmt = " 123456789";
	if (!idx) {		// 9999 or less: use 1234 format
		c = buf[0] = " 123456789"[v/10000];
		if (c!=' ') fmt = "0123456789";
		c = buf[1] = fmt[v/1000%10];
		if (c!=' ') fmt = "0123456789";
		buf[2] = fmt[v/100%10];
		buf[3] = "0123456789"[v/10%10];
	} else {
		if (v>=10*10) {	// scaled value is >=10: use 123M format
			c = buf[0] = " 123456789"[v/1000];
			if (c!=' ') fmt = "0123456789";
			buf[1] = fmt[v/100%10];
			buf[2] = "0123456789"[v/10%10];
		} else {	// scaled value is <10: use 1.2M format
			buf[0] = "0123456789"[v/10];
			buf[1] = '.';
			buf[2] = "0123456789"[v%10];
		}
		// see http://en.wikipedia.org/wiki/Tera
		buf[3] = " kMGTPEZY"[idx];
	}
	buf[4] = '\0';
}

// Convert unsigned integer to ascii, writing into supplied buffer.  A
// truncated result is always null terminated (unless buflen is 0), and
// contains the first few digits of the result ala strncpy.
void BUG_sizeof_unsigned_not_4(void);
void utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
	unsigned i, out, res;
	if (sizeof(unsigned) != 4)
		BUG_sizeof_unsigned_not_4();
	if (buflen) {
		out = 0;
		for (i = 1000000000; i; i /= 10) {
			res = n / i;
			if (res || out || i == 1) {
				if (!--buflen) break;
				out++;
				n -= res*i;
				*buf++ = '0' + res;
			}
		}
		*buf = '\0';
	}
}

// Convert signed integer to ascii, like utoa_to_buf()
void itoa_to_buf(int n, char *buf, unsigned buflen)
{
	if (buflen && n<0) {
		n = -n;
		*buf++ = '-';
		buflen--;
	}
	utoa_to_buf((unsigned)n, buf, buflen);
}

// The following two functions use a static buffer, so calling either one a
// second time will overwrite previous results.
//
// The largest 32 bit integer is -2 billion plus null terminator, or 12 bytes.
// Int should always be 32 bits on any remotely Unix-like system, see
// http://www.unix.org/whitepapers/64bit.html for the reasons why.

static char local_buf[12];

// Convert unsigned integer to ascii using a static buffer (returned).
char *utoa(unsigned n)
{
	utoa_to_buf(n, local_buf, sizeof(local_buf));

	return local_buf;
}

// Convert signed integer to ascii using a static buffer (returned).
char *itoa(int n)
{
	itoa_to_buf(n, local_buf, sizeof(local_buf));

	return local_buf;
}

// Emit a string of hex representation of bytes
char *bin2hex(char *p, const char *cp, int count)
{
	while (count) {
		unsigned char c = *cp++;
		/* put lowercase hex digits */
		*p++ = 0x20 | bb_hexdigits_upcase[c >> 4];
		*p++ = 0x20 | bb_hexdigits_upcase[c & 0xf];
		count--;
	}
	return p;
}

// 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 xsetgid(gid_t gid)
{
	if (setgid(gid)) bb_error_msg_and_die("setgid");
}

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

// Return how long the file at fd is, if there's any way to determine it.
off_t fdlength(int fd)
{
	off_t bottom = 0, top = 0, pos;
	long size;

	// If the ioctl works for this, return it.

	if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;

	// FIXME: explain why lseek(SEEK_END) is not used here!

	// If not, do a binary search for the last location we can read.  (Some
	// block devices don't do BLKGETSIZE right.)

	do {
		char temp;

		pos = bottom + (top - bottom) / 2;

		// If we can read from the current location, it's bigger.

		if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
			if (bottom == top) bottom = top = (top+1) * 2;
			else bottom = pos;

		// If we can't, it's smaller.

		} else {
			if (bottom == top) {
				if (!top) return 0;
				bottom = top/2;
			}
			else top = pos;
		}
	} while (bottom + 1 != top);

	return pos + 1;
}

// Die with an error message if we can't malloc() enough space and do an
// sprintf() into that space.
char *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 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);
	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) {
		full_write(fd, string_ptr, r);
		free(string_ptr);
	}
	return r;
}
#endif

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

	fclose(file);
}

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

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

	if ((dp = opendir(path)) == NULL) {
		bb_perror_msg("cannot open '%s'", path);
		return NULL;
	}
	return dp;
}

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

	if ((dp = opendir(path)) == NULL)
		bb_perror_msg_and_die("cannot open '%s'", path);
	return dp;
}

#ifndef BB_NOMMU
// Die with an error message if we can't daemonize.
void xdaemon(int nochdir, int noclose)
{
	if (daemon(nochdir, noclose))
		bb_perror_msg_and_die("daemon");
}
#endif

void bb_sanitize_stdio_maybe_daemonize(int daemonize)
{
	int fd;
	/* Mega-paranoid */
	fd = xopen(bb_dev_null, O_RDWR);
	while (fd < 2)
		fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
	if (daemonize) {
		pid_t pid = fork();
		if (pid < 0) /* wtf? */
			bb_perror_msg_and_die("fork");
		if (pid) /* parent */
			exit(0);
    		/* child */
		/* if daemonizing, make sure we detach from stdio */
		setsid();
		dup2(fd, 0);
		dup2(fd, 1);
		dup2(fd, 2);
	}
	while (fd > 2)
		close(fd--); /* close everything after fd#2 */
}
void bb_sanitize_stdio(void)
{
	bb_sanitize_stdio_maybe_daemonize(0);
}
void bb_daemonize(void)
{
	bb_sanitize_stdio_maybe_daemonize(1);
}

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

	if (r < 0) bb_perror_msg_and_die("socket");

	return r;
}

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

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

/* It is perfectly ok to pass in a NULL for either width or for
 * height, in which case that value will not be set.  */
int get_terminal_width_height(int fd, int *width, int *height)
{
	struct winsize win = { 0, 0, 0, 0 };
	int ret = ioctl(fd, TIOCGWINSZ, &win);

	if (height) {
		if (!win.ws_row) {
			char *s = getenv("LINES");
			if (s) win.ws_row = atoi(s);
		}
		if (win.ws_row <= 1 || win.ws_row >= 30000)
			win.ws_row = 24;
		*height = (int) win.ws_row;
	}

	if (width) {
		if (!win.ws_col) {
			char *s = getenv("COLUMNS");
			if (s) win.ws_col = atoi(s);
		}
		if (win.ws_col <= 1 || win.ws_col >= 30000)
			win.ws_col = 80;
		*width = (int) win.ws_col;
	}

	return ret;
}
1	niro	532	/* 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 Denis Vlasenko
8			*
9			* Licensed under GPL version 2, see file LICENSE in this tarball for details.
10			*/
11
12			#include "busybox.h"
13
14			/* All the functions starting with "x" call bb_error_msg_and_die() if they
15			* fail, so callers never need to check for errors. If it returned, it
16			* succeeded. */
17
18			#ifndef DMALLOC
19			/* dmalloc provides variants of these that do abort() on failure.
20			* Since dmalloc's prototypes overwrite the impls here as they are
21			* included after these prototypes in libbb.h, all is well.
22			*/
23			// Die if we can't allocate size bytes of memory.
24			void *xmalloc(size_t size)
25			{
26			void *ptr = malloc(size);
27			if (ptr == NULL && size != 0)
28			bb_error_msg_and_die(bb_msg_memory_exhausted);
29			return ptr;
30			}
31
32			// Die if we can't resize previously allocated memory. (This returns a pointer
33			// to the new memory, which may or may not be the same as the old memory.
34			// It'll copy the contents to a new chunk and free the old one if necessary.)
35			void xrealloc(void ptr, size_t size)
36			{
37			ptr = realloc(ptr, size);
38			if (ptr == NULL && size != 0)
39			bb_error_msg_and_die(bb_msg_memory_exhausted);
40			return ptr;
41			}
42			#endif /* DMALLOC */
43
44			// Die if we can't allocate and zero size bytes of memory.
45			void *xzalloc(size_t size)
46			{
47			void *ptr = xmalloc(size);
48			memset(ptr, 0, size);
49			return ptr;
50			}
51
52			// Die if we can't copy a string to freshly allocated memory.
53			char * xstrdup(const char *s)
54			{
55			char *t;
56
57			if (s == NULL)
58			return NULL;
59
60			t = strdup(s);
61
62			if (t == NULL)
63			bb_error_msg_and_die(bb_msg_memory_exhausted);
64
65			return t;
66			}
67
68			// Die if we can't allocate n+1 bytes (space for the null terminator) and copy
69			// the (possibly truncated to length n) string into it.
70			char * xstrndup(const char *s, int n)
71			{
72			int m;
73			char *t;
74
75			if (ENABLE_DEBUG && s == NULL)
76			bb_error_msg_and_die("xstrndup bug");
77
78			/* We can just xmalloc(n+1) and strncpy into it, */
79			/* but think about xstrndup("abc", 10000) wastage! */
80			m = n;
81			t = (char*) s;
82			while (m) {
83			if (!*t) break;
84			m--;
85			t++;
86			}
87			n -= m;
88			t = xmalloc(n + 1);
89			t[n] = '\0';
90
91			return memcpy(t, s, n);
92			}
93
94			// Die if we can't open a file and return a FILE * to it.
95			// Notice we haven't got xfread(), This is for use with fscanf() and friends.
96			FILE xfopen(const char path, const char *mode)
97			{
98			FILE *fp = fopen(path, mode);
99			if (fp == NULL)
100			bb_perror_msg_and_die("%s", path);
101			return fp;
102			}
103
104			// Die if we can't open an existing file and return an fd.
105			int xopen(const char *pathname, int flags)
106			{
107			//if (ENABLE_DEBUG && (flags & O_CREAT))
108			// bb_error_msg_and_die("xopen() with O_CREAT");
109
110			return xopen3(pathname, flags, 0666);
111			}
112
113			// Die if we can't open a new file and return an fd.
114			int xopen3(const char *pathname, int flags, int mode)
115			{
116			int ret;
117
118			ret = open(pathname, flags, mode);
119			if (ret < 0) {
120			bb_perror_msg_and_die("%s", pathname);
121			}
122			return ret;
123			}
124
125			// Turn on nonblocking I/O on a fd
126			int ndelay_on(int fd)
127			{
128			return fcntl(fd,F_SETFL,fcntl(fd,F_GETFL,0) \| O_NONBLOCK);
129			}
130
131			int ndelay_off(int fd)
132			{
133			return fcntl(fd,F_SETFL,fcntl(fd,F_GETFL,0) & ~O_NONBLOCK);
134			}
135
136			// Die with an error message if we can't write the entire buffer.
137			void xwrite(int fd, const void *buf, size_t count)
138			{
139			if (count) {
140			ssize_t size = full_write(fd, buf, count);
141			if (size != count)
142			bb_error_msg_and_die("short write");
143			}
144			}
145
146			// Die with an error message if we can't lseek to the right spot.
147			off_t xlseek(int fd, off_t offset, int whence)
148			{
149			off_t off = lseek(fd, offset, whence);
150			if (off == (off_t)-1) {
151			if (whence == SEEK_SET)
152			bb_perror_msg_and_die("lseek(%"OFF_FMT"u)", offset);
153			bb_perror_msg_and_die("lseek");
154			}
155			return off;
156			}
157
158			// Die with supplied filename if this FILE * has ferror set.
159			void die_if_ferror(FILE fp, const char fn)
160			{
161			if (ferror(fp)) {
162			bb_error_msg_and_die("%s: I/O error", fn);
163			}
164			}
165
166			// Die with an error message if stdout has ferror set.
167			void die_if_ferror_stdout(void)
168			{
169			die_if_ferror(stdout, bb_msg_standard_output);
170			}
171
172			// Die with an error message if we have trouble flushing stdout.
173			void xfflush_stdout(void)
174			{
175			if (fflush(stdout)) {
176			bb_perror_msg_and_die(bb_msg_standard_output);
177			}
178			}
179
180			// This does a fork/exec in one call, using vfork(). Return PID of new child,
181			// -1 for failure. Runs argv[0], searching path if that has no / in it.
182			pid_t spawn(char **argv)
183			{
184			/* Why static? */
185			static int failed;
186			pid_t pid;
187			void *app = ENABLE_FEATURE_SH_STANDALONE_SHELL ? find_applet_by_name(argv[0]) : 0;
188
189			// Be nice to nommu machines.
190			failed = 0;
191			pid = vfork();
192			if (pid < 0) return pid;
193			if (!pid) {
194			execvp(app ? CONFIG_BUSYBOX_EXEC_PATH : *argv, argv);
195
196			// We're sharing a stack with blocked parent, let parent know we failed
197			// and then exit to unblock parent (but don't run atexit() stuff, which
198			// would screw up parent.)
199
200			failed = errno;
201			_exit(0);
202			}
203			if (failed) {
204			errno = failed;
205			return -1;
206			}
207			return pid;
208			}
209
210			// Die with an error message if we can't spawn a child process.
211			pid_t xspawn(char **argv)
212			{
213			pid_t pid = spawn(argv);
214			if (pid < 0) bb_perror_msg_and_die("%s", *argv);
215			return pid;
216			}
217
218			// Wait for the specified child PID to exit, returning child's error return.
219			int wait4pid(int pid)
220			{
221			int status;
222
223			if (pid == -1 \|\| waitpid(pid, &status, 0) == -1) return -1;
224			if (WIFEXITED(status)) return WEXITSTATUS(status);
225			if (WIFSIGNALED(status)) return WTERMSIG(status);
226			return 0;
227			}
228
229			void xsetenv(const char key, const char value)
230			{
231			if (setenv(key, value, 1))
232			bb_error_msg_and_die(bb_msg_memory_exhausted);
233			}
234
235			// Converts unsigned long long value into compact 4-char
236			// representation. Examples: "1234", "1.2k", " 27M", "123T"
237			// Fifth char is always '\0'
238			void smart_ulltoa5(unsigned long long ul, char buf[5])
239			{
240			char *fmt;
241			char c;
242			unsigned v,idx = 0;
243			ul *= 10;
244			if (ul > 9999*10) { // do not scale if 9999 or less
245			while (ul >= 10000) {
246			ul /= 1024;
247			idx++;
248			}
249			}
250			v = ul; // ullong divisions are expensive, avoid them
251
252			fmt = " 123456789";
253			if (!idx) { // 9999 or less: use 1234 format
254			c = buf[0] = " 123456789"[v/10000];
255			if (c!=' ') fmt = "0123456789";
256			c = buf[1] = fmt[v/1000%10];
257			if (c!=' ') fmt = "0123456789";
258			buf[2] = fmt[v/100%10];
259			buf[3] = "0123456789"[v/10%10];
260			} else {
261			if (v>=10*10) { // scaled value is >=10: use 123M format
262			c = buf[0] = " 123456789"[v/1000];
263			if (c!=' ') fmt = "0123456789";
264			buf[1] = fmt[v/100%10];
265			buf[2] = "0123456789"[v/10%10];
266			} else { // scaled value is <10: use 1.2M format
267			buf[0] = "0123456789"[v/10];
268			buf[1] = '.';
269			buf[2] = "0123456789"[v%10];
270			}
271			// see http://en.wikipedia.org/wiki/Tera
272			buf[3] = " kMGTPEZY"[idx];
273			}
274			buf[4] = '\0';
275			}
276
277			// Convert unsigned integer to ascii, writing into supplied buffer. A
278			// truncated result is always null terminated (unless buflen is 0), and
279			// contains the first few digits of the result ala strncpy.
280			void BUG_sizeof_unsigned_not_4(void);
281			void utoa_to_buf(unsigned n, char *buf, unsigned buflen)
282			{
283			unsigned i, out, res;
284			if (sizeof(unsigned) != 4)
285			BUG_sizeof_unsigned_not_4();
286			if (buflen) {
287			out = 0;
288			for (i = 1000000000; i; i /= 10) {
289			res = n / i;
290			if (res \|\| out \|\| i == 1) {
291			if (!--buflen) break;
292			out++;
293			n -= res*i;
294			*buf++ = '0' + res;
295			}
296			}
297			*buf = '\0';
298			}
299			}
300
301			// Convert signed integer to ascii, like utoa_to_buf()
302			void itoa_to_buf(int n, char *buf, unsigned buflen)
303			{
304			if (buflen && n<0) {
305			n = -n;
306			*buf++ = '-';
307			buflen--;
308			}
309			utoa_to_buf((unsigned)n, buf, buflen);
310			}
311
312			// The following two functions use a static buffer, so calling either one a
313			// second time will overwrite previous results.
314			//
315			// The largest 32 bit integer is -2 billion plus null terminator, or 12 bytes.
316			// Int should always be 32 bits on any remotely Unix-like system, see
317			// http://www.unix.org/whitepapers/64bit.html for the reasons why.
318
319			static char local_buf[12];
320
321			// Convert unsigned integer to ascii using a static buffer (returned).
322			char *utoa(unsigned n)
323			{
324			utoa_to_buf(n, local_buf, sizeof(local_buf));
325
326			return local_buf;
327			}
328
329			// Convert signed integer to ascii using a static buffer (returned).
330			char *itoa(int n)
331			{
332			itoa_to_buf(n, local_buf, sizeof(local_buf));
333
334			return local_buf;
335			}
336
337			// Emit a string of hex representation of bytes
338			char bin2hex(char p, const char *cp, int count)
339			{
340			while (count) {
341			unsigned char c = *cp++;
342			/* put lowercase hex digits */
343			*p++ = 0x20 \| bb_hexdigits_upcase[c >> 4];
344			*p++ = 0x20 \| bb_hexdigits_upcase[c & 0xf];
345			count--;
346			}
347			return p;
348			}
349
350			// Die with an error message if we can't set gid. (Because resource limits may
351			// limit this user to a given number of processes, and if that fills up the
352			// setgid() will fail and we'll _still_be_root_, which is bad.)
353			void xsetgid(gid_t gid)
354			{
355			if (setgid(gid)) bb_error_msg_and_die("setgid");
356			}
357
358			// Die with an error message if we can't set uid. (See xsetgid() for why.)
359			void xsetuid(uid_t uid)
360			{
361			if (setuid(uid)) bb_error_msg_and_die("setuid");
362			}
363
364			// Return how long the file at fd is, if there's any way to determine it.
365			off_t fdlength(int fd)
366			{
367			off_t bottom = 0, top = 0, pos;
368			long size;
369
370			// If the ioctl works for this, return it.
371
372			if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
373
374			// FIXME: explain why lseek(SEEK_END) is not used here!
375
376			// If not, do a binary search for the last location we can read. (Some
377			// block devices don't do BLKGETSIZE right.)
378
379			do {
380			char temp;
381
382			pos = bottom + (top - bottom) / 2;
383
384			// If we can read from the current location, it's bigger.
385
386			if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
387			if (bottom == top) bottom = top = (top+1) * 2;
388			else bottom = pos;
389
390			// If we can't, it's smaller.
391
392			} else {
393			if (bottom == top) {
394			if (!top) return 0;
395			bottom = top/2;
396			}
397			else top = pos;
398			}
399			} while (bottom + 1 != top);
400
401			return pos + 1;
402			}
403
404			// Die with an error message if we can't malloc() enough space and do an
405			// sprintf() into that space.
406			char xasprintf(const char format, ...)
407			{
408			va_list p;
409			int r;
410			char *string_ptr;
411
412			#if 1
413			// GNU extension
414			va_start(p, format);
415			r = vasprintf(&string_ptr, format, p);
416			va_end(p);
417			#else
418			// Bloat for systems that haven't got the GNU extension.
419			va_start(p, format);
420			r = vsnprintf(NULL, 0, format, p);
421			va_end(p);
422			string_ptr = xmalloc(r+1);
423			va_start(p, format);
424			r = vsnprintf(string_ptr, r+1, format, p);
425			va_end(p);
426			#endif
427
428			if (r < 0) bb_error_msg_and_die(bb_msg_memory_exhausted);
429			return string_ptr;
430			}
431
432			#if 0 /* If we will ever meet a libc which hasn't [f]dprintf... */
433			int fdprintf(int fd, const char *format, ...)
434			{
435			va_list p;
436			int r;
437			char *string_ptr;
438
439			#if 1
440			// GNU extension
441			va_start(p, format);
442			r = vasprintf(&string_ptr, format, p);
443			va_end(p);
444			#else
445			// Bloat for systems that haven't got the GNU extension.
446			va_start(p, format);
447			r = vsnprintf(NULL, 0, format, p);
448			va_end(p);
449			string_ptr = xmalloc(r+1);
450			va_start(p, format);
451			r = vsnprintf(string_ptr, r+1, format, p);
452			va_end(p);
453			#endif
454
455			if (r >= 0) {
456			full_write(fd, string_ptr, r);
457			free(string_ptr);
458			}
459			return r;
460			}
461			#endif
462
463			// Die with an error message if we can't copy an entire FILE * to stdout, then
464			// close that file.
465			void xprint_and_close_file(FILE *file)
466			{
467			fflush(stdout);
468			// copyfd outputs error messages for us.
469			if (bb_copyfd_eof(fileno(file), 1) == -1)
470			exit(xfunc_error_retval);
471
472			fclose(file);
473			}
474
475			// Die if we can't chdir to a new path.
476			void xchdir(const char *path)
477			{
478			if (chdir(path))
479			bb_perror_msg_and_die("chdir(%s)", path);
480			}
481
482			// Print a warning message if opendir() fails, but don't die.
483			DIR warn_opendir(const char path)
484			{
485			DIR *dp;
486
487			if ((dp = opendir(path)) == NULL) {
488			bb_perror_msg("cannot open '%s'", path);
489			return NULL;
490			}
491			return dp;
492			}
493
494			// Die with an error message if opendir() fails.
495			DIR xopendir(const char path)
496			{
497			DIR *dp;
498
499			if ((dp = opendir(path)) == NULL)
500			bb_perror_msg_and_die("cannot open '%s'", path);
501			return dp;
502			}
503
504			#ifndef BB_NOMMU
505			// Die with an error message if we can't daemonize.
506			void xdaemon(int nochdir, int noclose)
507			{
508			if (daemon(nochdir, noclose))
509			bb_perror_msg_and_die("daemon");
510			}
511			#endif
512
513			void bb_sanitize_stdio_maybe_daemonize(int daemonize)
514			{
515			int fd;
516			/* Mega-paranoid */
517			fd = xopen(bb_dev_null, O_RDWR);
518			while (fd < 2)
519			fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
520			if (daemonize) {
521			pid_t pid = fork();
522			if (pid < 0) /* wtf? */
523			bb_perror_msg_and_die("fork");
524			if (pid) /* parent */
525			exit(0);
526			/* child */
527			/* if daemonizing, make sure we detach from stdio */
528			setsid();
529			dup2(fd, 0);
530			dup2(fd, 1);
531			dup2(fd, 2);
532			}
533			while (fd > 2)
534			close(fd--); /* close everything after fd#2 */
535			}
536			void bb_sanitize_stdio(void)
537			{
538			bb_sanitize_stdio_maybe_daemonize(0);
539			}
540			void bb_daemonize(void)
541			{
542			bb_sanitize_stdio_maybe_daemonize(1);
543			}
544
545			// Die with an error message if we can't open a new socket.
546			int xsocket(int domain, int type, int protocol)
547			{
548			int r = socket(domain, type, protocol);
549
550			if (r < 0) bb_perror_msg_and_die("socket");
551
552			return r;
553			}
554
555			// Die with an error message if we can't bind a socket to an address.
556			void xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
557			{
558			if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
559			}
560
561			// Die with an error message if we can't listen for connections on a socket.
562			void xlisten(int s, int backlog)
563			{
564			if (listen(s, backlog)) bb_perror_msg_and_die("listen");
565			}
566
567			// xstat() - a stat() which dies on failure with meaningful error message
568			void xstat(char name, struct stat stat_buf)
569			{
570			if (stat(name, stat_buf))
571			bb_perror_msg_and_die("can't stat '%s'", name);
572			}
573
574			/* It is perfectly ok to pass in a NULL for either width or for
575			* height, in which case that value will not be set. */
576			int get_terminal_width_height(int fd, int width, int height)
577			{
578			struct winsize win = { 0, 0, 0, 0 };
579			int ret = ioctl(fd, TIOCGWINSZ, &win);
580
581			if (height) {
582			if (!win.ws_row) {
583			char *s = getenv("LINES");
584			if (s) win.ws_row = atoi(s);
585			}
586			if (win.ws_row <= 1 \|\| win.ws_row >= 30000)
587			win.ws_row = 24;
588			*height = (int) win.ws_row;
589			}
590
591			if (width) {
592			if (!win.ws_col) {
593			char *s = getenv("COLUMNS");
594			if (s) win.ws_col = atoi(s);
595			}
596			if (win.ws_col <= 1 \|\| win.ws_col >= 30000)
597			win.ws_col = 80;
598			*width = (int) win.ws_col;
599			}
600
601			return ret;
602			}