hush/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 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"

#ifndef __GNO__
/* 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;
}
#endif

#ifdef __GNO__

# undef close
# undef fclose
# undef dup2

# define N_CLOEXEC_ENT 4
static struct cloexec_ent cloexec_table[N_CLOEXEC_ENT];

struct cloexec_ent *get_cloexec_ent(pid_t pid)
{
	int i;
	for (i = 0; i < N_CLOEXEC_ENT; i++) {
		if (cloexec_table[i].pid == pid)
			return &cloexec_table[i];
	}
	return NULL;
}

int new_cloexec_ent(uint32_t initial_mask)
{
	int i;
	int newpid = getpid();
	
	/* Find an entry that doesn't correspond to an active process */
	for (i = 0; i < N_CLOEXEC_ENT; i++) {
		int pid = cloexec_table[i].pid;
		if (pid == 0 || pid == newpid)
			break;
		if (_getpgrp(pid) == -1 && errno == ESRCH)
			break;
	}
	
	if (i == N_CLOEXEC_ENT)
		return -1;
	
	cloexec_table[i].pid = newpid;
	cloexec_table[i].cloexec_mask = initial_mask;
	return 0;
}

void close_cloexec_fds(void)
{
	int fd;
	struct cloexec_ent *ent = get_cloexec_ent(getpid());
	if (ent == NULL)
		return;
	for (fd = 0; fd < 32; fd++) {
		if (ent->cloexec_mask & (1L << fd)) {
			close(fd);
		}
	}
	
	/* Free the entry (since we're about to exec) */
	ent->pid = 0;
}

void close_on_exec_on(int fd)
{
	struct cloexec_ent *ent = get_cloexec_ent(getpid());
	if (ent == NULL || fd < 0 || fd >= 32)
		return;
	ent->cloexec_mask |= (1L << fd);
}

void close_on_exec_off(int fd)
{
	struct cloexec_ent *ent = get_cloexec_ent(getpid());
	if (ent == NULL || fd < 0 || fd >= 32)
		return;
	ent->cloexec_mask &= ~(1L << fd);
}

int close_wrapper(int fd)
{
	int result = close(fd);
	if (result == 0)
		close_on_exec_off(fd);
	return result;
}

int fclose_wrapper(FILE *stream)
{
	int fd = fileno(stream);
	int result = fclose(stream);
	if (result == 0)
		close_on_exec_off(fd);
	return result;
}

int dup2_wrapper(int fd, int fd2)
{
	int result = dup2(fd, fd2);
	if (result == 0 && fd != fd2)
		close_on_exec_off(fd2);
	return result;
}

# define close(fd) close_wrapper(fd)
# define fclose(stream) fclose_wrapper(stream)
# define dup2(fd, fd2) dup2_wrapper(fd, fd2)

#else

void FAST_FUNC close_on_exec_on(int fd)
{
	fcntl(fd, F_SETFD, FD_CLOEXEC);
}

#endif

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)
{
	unsigned i, out, res;

	if (buflen) {
		out = 0;
		if (sizeof(n) == 2)
		// 2^16-1 = 65535
			i = 10000;
		else
		if (sizeof(n) == 4)
		// 2^32-1 = 4294967295
			i = 1000000000;
#if UINT_MAX > 4294967295 /* prevents warning about "const too large" */
		else
		if (sizeof(n) == 8)
		// 2^64-1 = 18446744073709551615
			i = 10 ** 19;
#endif
		else
			bb_error_msg_and_die("Unsupported sizeof(unsigned)");
		for (; i; i /= 10) {
			res = n / i;
			n = n % i;
			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 + 2];

/* 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)
{
	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;
}

/* 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)
{
#ifdef __GNO__
	if (ch == '\n')
		ch = '\r';
#endif
	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)
{
	if (value == 0) {
		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;

	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);
	return err;
}

#ifndef __GNO__
int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
{
	return tcsetattr(STDIN_FILENO, TCSANOW, tp);
}
#endif

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;
}