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 GPLv2, see file LICENSE in this source tree.
*/
/* 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)
{
int flags = fcntl(fd, F_GETFL);
if (flags & O_NONBLOCK)
return flags;
fcntl(fd, F_SETFL, flags | O_NONBLOCK);
return flags;
}
int FAST_FUNC ndelay_off(int fd)
{
int flags = fcntl(fd, F_GETFL);
if (!(flags & O_NONBLOCK))
return flags;
fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
return flags;
}
void FAST_FUNC close_on_exec_on(int fd)
{
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.
*/
char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
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unsigned i, out, res;
if (buflen) {
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out = 0;
BUILD_BUG_ON(sizeof(n) != 4 && sizeof(n) != 8);
if (sizeof(n) == 4)
// 2^32-1 = 4294967295
i = 1000000000;
#if UINT_MAX > 0xffffffff /* prevents warning about "const too large" */
else
if (sizeof(n) == 8)
// 2^64-1 = 18446744073709551615
i = 10000000000000000000;
#endif
for (; i; i /= 10) {
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res = n / i;
n = n % i;
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if (res || out || i == 1) {
if (--buflen == 0)
break;
out++;
*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)
{
if (!buflen)
return buf;
if (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 NUL, or 1+10+1=12 bytes.
// It so happens that sizeof(int) * 3 is enough for 32+ bit ints.
// (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) - 1)) = '\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) - 1)) = '\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;
}
/* Convert "[x]x[:][x]x[:][x]x[:][x]x" hex string to binary, no more than COUNT bytes */
char* FAST_FUNC hex2bin(char *dst, const char *str, int count)
{
errno = EINVAL;
while (*str && count) {
uint8_t val;
uint8_t c = *str++;
if (isdigit(c))
val = c - '0';
else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
val = (c|0x20) - ('a' - 10);
else
return NULL;
val <<= 4;
c = *str;
if (isdigit(c))
val |= c - '0';
else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
val |= (c|0x20) - ('a' - 10);
else if (c == ':' || c == '\0')
val >>= 4;
else
return NULL;
*dst++ = val;
if (c != '\0')
str++;
if (*str == ':')
str++;
count--;
}
errno = (*str ? ERANGE : 0);
return dst;
}
/* 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
int FAST_FUNC bb_putchar_stderr(char ch)
{
return write(STDERR_FILENO, &ch, 1);
}
ssize_t FAST_FUNC full_write1_str(const char *str)
{
return full_write(STDOUT_FILENO, str, strlen(str));
}
ssize_t FAST_FUNC full_write2_str(const char *str)
{
return full_write(STDERR_FILENO, str, strlen(str));
}
static int wh_helper(int value, int def_val, const char *env_name, int *err)
{
/* Envvars override even if "value" from ioctl is valid (>0).
* Rationale: it's impossible to guess what user wants.
* For example: "man CMD | ...": should "man" format output
* to stdout's width? stdin's width? /dev/tty's width? 80 chars?
* We _cant_ know it. If "..." saves text for e.g. email,
* then it's probably 80 chars.
* If "..." is, say, "grep -v DISCARD | $PAGER", then user
* would prefer his tty's width to be used!
*
* Since we don't know, at least allow user to do this:
* "COLUMNS=80 man CMD | ..."
*/
char *s = getenv(env_name);
if (s) {
value = atoi(s);
/* If LINES/COLUMNS are set, pretend that there is
* no error getting w/h, this prevents some ugly
* cursor tricks by our callers */
*err = 0;
}
if (value <= 1 || value >= 30000)
value = def_val;
return value;
}
/* 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;
int err;
int close_me = -1;
if (fd == -1) {
if (isatty(STDOUT_FILENO))
fd = STDOUT_FILENO;
else
if (isatty(STDERR_FILENO))
fd = STDERR_FILENO;
else
if (isatty(STDIN_FILENO))
fd = STDIN_FILENO;
else
close_me = fd = open("/dev/tty", O_RDONLY);
}
win.ws_row = 0;
win.ws_col = 0;
/* I've seen ioctl returning 0, but row/col is (still?) 0.
* We treat that as an error too. */
err = ioctl(fd, TIOCGWINSZ, &win) != 0 || win.ws_row == 0;
if (height)
*height = wh_helper(win.ws_row, 24, "LINES", &err);
if (width)
*width = wh_helper(win.ws_col, 80, "COLUMNS", &err);
if (close_me >= 0)
close(close_me);
return err;
}
int FAST_FUNC get_terminal_width(int fd)
{
unsigned width;
get_terminal_width_height(fd, &width, NULL);
return width;
}
int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
{
return tcsetattr(STDIN_FILENO, TCSANOW, tp);
}
int FAST_FUNC get_termios_and_make_raw(int fd, struct termios *newterm, struct termios *oldterm, int flags)
{
//TODO: slattach, shell read might be adapted to use this too: grep for "tcsetattr", "[VTIME] = 0"
int r;
memset(oldterm, 0, sizeof(*oldterm)); /* paranoia */
r = tcgetattr(fd, oldterm);
*newterm = *oldterm;
/* Turn off buffered input (ICANON)
* Turn off echoing (ECHO)
* and separate echoing of newline (ECHONL, normally off anyway)
*/
newterm->c_lflag &= ~(ICANON | ECHO | ECHONL);
if (flags & TERMIOS_CLEAR_ISIG) {
/* dont recognize INT/QUIT/SUSP chars */
newterm->c_lflag &= ~ISIG;
}
/* reads will block only if < 1 char is available */
newterm->c_cc[VMIN] = 1;
/* no timeout (reads block forever) */
newterm->c_cc[VTIME] = 0;
if (flags & TERMIOS_RAW_CRNL) {
/* IXON, IXOFF, and IXANY:
* IXOFF=1: sw flow control is enabled on input queue:
* tty transmits a STOP char when input queue is close to full
* and transmits a START char when input queue is nearly empty.
* IXON=1: sw flow control is enabled on output queue:
* tty will stop sending if STOP char is received,
* and resume sending if START is received, or if any char
* is received and IXANY=1.
*/
/* IXON=0: XON/XOFF chars are treated as normal chars (why we do this?) */
/* dont convert CR to NL on input */
newterm->c_iflag &= ~(IXON | ICRNL);
/* dont convert NL to CR+NL on output */
newterm->c_oflag &= ~(ONLCR);
/* Maybe clear more c_oflag bits? Usually, only OPOST and ONLCR are set.
* OPOST Enable output processing (reqd for OLCUC and *NL* bits to work)
* OLCUC Map lowercase characters to uppercase on output.
* OCRNL Map CR to NL on output.
* ONOCR Don't output CR at column 0.
* ONLRET Don't output CR.
*/
}
if (flags & TERMIOS_RAW_INPUT) {
#ifndef IMAXBEL
# define IMAXBEL 0
#endif
#ifndef IUCLC
# define IUCLC 0
#endif
#ifndef IXANY
# define IXANY 0
#endif
/* IXOFF=0: disable sending XON/XOFF if input buf is full */
/* IXON=0: input XON/XOFF chars are not special */
/* dont convert anything on input */
newterm->c_iflag &= ~(IXOFF|IXON|IXANY|BRKINT|INLCR|ICRNL|IUCLC|IMAXBEL);
}
return r;
}
int FAST_FUNC set_termios_to_raw(int fd, struct termios *oldterm, int flags)
{
struct termios newterm;
get_termios_and_make_raw(fd, &newterm, oldterm, flags);
return tcsetattr(fd, TCSANOW, &newterm);
}
pid_t FAST_FUNC safe_waitpid(pid_t pid, int *wstat, int options)
{
pid_t r;
do
r = waitpid(pid, wstat, options);
while ((r == -1) && (errno == EINTR));
return r;
}
pid_t FAST_FUNC wait_any_nohang(int *wstat)
{
return safe_waitpid(-1, wstat, WNOHANG);
}
// Wait for the specified child PID to exit, returning child's error return.
int FAST_FUNC wait4pid(pid_t pid)
{
int status;
if (pid <= 0) {
/*errno = ECHILD; -- wrong. */
/* we expect errno to be already set from failed [v]fork/exec */
return -1;
}
if (safe_waitpid(pid, &status, 0) == -1)
return -1;
if (WIFEXITED(status))
return WEXITSTATUS(status);
if (WIFSIGNALED(status))
return WTERMSIG(status) + 0x180;
return 0;
}
// Useful when we do know that pid is valid, and we just want to wait
// for it to exit. Not existing pid is fatal. waitpid() status is not returned.
int FAST_FUNC wait_for_exitstatus(pid_t pid)
{
int exit_status, n;
n = safe_waitpid(pid, &exit_status, 0);
if (n < 0)
bb_perror_msg_and_die("waitpid");
return exit_status;
}