source: MondoRescue/branches/3.0/mindi-busybox/libbb/xfuncs.c@ 2899

/* 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)
{
    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.
 */
void BUG_sizeof(void);
char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
    unsigned i, out, res;

    if (buflen) {
        out = 0;
        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 = 10000000000000000000;
#endif
        else
            BUG_sizeof();
        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];

/* 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)
{
    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, pretent 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;
}

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

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;
}