busybox/libbb/xfuncs.c

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/* 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.
*
* TODO: move xmalloc() and xatonum() here.
*/
#include "libbb.h"
/* Turn on nonblocking I/O on a fd */
int FAST_FUNC ndelay_on(int fd)
{
return fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
}
int FAST_FUNC ndelay_off(int fd)
{
return fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK);
}
int FAST_FUNC close_on_exec_on(int fd)
{
return fcntl(fd, F_SETFD, FD_CLOEXEC);
}
char* FAST_FUNC strncpy_IFNAMSIZ(char *dst, const char *src)
{
#ifndef IFNAMSIZ
enum { IFNAMSIZ = 16 };
#endif
return strncpy(dst, src, IFNAMSIZ);
}
// Convert unsigned integer to ascii, writing into supplied buffer.
// A truncated result contains the first few digits of the result ala strncpy.
// Returns a pointer past last generated digit, does _not_ store NUL.
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void BUG_sizeof_unsigned_not_4(void);
char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
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unsigned i, out, res;
if (sizeof(unsigned) != 4)
BUG_sizeof_unsigned_not_4();
if (buflen) {
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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;
}
}
}
return buf;
}
/* Convert signed integer to ascii, like utoa_to_buf() */
char* FAST_FUNC itoa_to_buf(int n, char *buf, unsigned buflen)
{
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if (buflen && n < 0) {
n = -n;
*buf++ = '-';
buflen--;
}
return 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.
// It so happens that sizeof(int) * 3 is enough for 32+ bits.
// (sizeof(int) * 3 + 2 is correct for any width, even 8-bit)
static char local_buf[sizeof(int) * 3];
// Convert unsigned integer to ascii using a static buffer (returned).
char* FAST_FUNC utoa(unsigned n)
{
*(utoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';
return local_buf;
}
/* Convert signed integer to ascii using a static buffer (returned). */
char* FAST_FUNC itoa(int n)
{
*(itoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';
return local_buf;
}
/* Emit a string of hex representation of bytes */
char* FAST_FUNC bin2hex(char *p, const char *cp, int count)
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{
while (count) {
unsigned char c = *cp++;
/* put lowercase hex digits */
*p++ = 0x20 | bb_hexdigits_upcase[c >> 4];
*p++ = 0x20 | bb_hexdigits_upcase[c & 0xf];
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count--;
}
return p;
}
/* Return how long the file at fd is, if there's any way to determine it. */
#ifdef UNUSED
off_t FAST_FUNC 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;
}
#endif
char* FAST_FUNC xmalloc_ttyname(int fd)
{
char *buf = xzalloc(128);
int r = ttyname_r(fd, buf, 127);
if (r) {
free(buf);
buf = NULL;
}
return buf;
}
/* 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 FAST_FUNC get_terminal_width_height(int fd, unsigned *width, unsigned *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;
}
int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
{
return tcsetattr(STDIN_FILENO, TCSANOW, tp);
}
void FAST_FUNC generate_uuid(uint8_t *buf)
{
/* http://www.ietf.org/rfc/rfc4122.txt
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | time_low |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | time_mid | time_hi_and_version |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |clk_seq_and_variant | node (0-1) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | node (2-5) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* IOW, uuid has this layout:
* uint32_t time_low (big endian)
* uint16_t time_mid (big endian)
* uint16_t time_hi_and_version (big endian)
* version is a 4-bit field:
* 1 Time-based
* 2 DCE Security, with embedded POSIX UIDs
* 3 Name-based (MD5)
* 4 Randomly generated
* 5 Name-based (SHA-1)
* uint16_t clk_seq_and_variant (big endian)
* variant is a 3-bit field:
* 0xx Reserved, NCS backward compatibility
* 10x The variant specified in rfc4122
* 110 Reserved, Microsoft backward compatibility
* 111 Reserved for future definition
* uint8_t node[6]
*
* For version 4, these bits are set/cleared:
* time_hi_and_version & 0x0fff | 0x4000
* clk_seq_and_variant & 0x3fff | 0x8000
*/
pid_t pid;
int i;
i = open("/dev/urandom", O_RDONLY);
if (i >= 0) {
read(i, buf, 16);
close(i);
}
/* Paranoia. /dev/urandom may be missing.
* rand() is guaranteed to generate at least [0, 2^15) range,
* but lowest bits in some libc are not so "random". */
srand(monotonic_us());
pid = getpid();
while (1) {
for (i = 0; i < 16; i++)
buf[i] ^= rand() >> 5;
if (pid == 0)
break;
srand(pid);
pid = 0;
}
/* version = 4 */
buf[4 + 2 ] = (buf[4 + 2 ] & 0x0f) | 0x40;
/* variant = 10x */
buf[4 + 2 + 2] = (buf[4 + 2 + 2] & 0x3f) | 0x80;
}