/* 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 */
void FAST_FUNC ndelay_on(int fd)
{
        int flags = fcntl(fd, F_GETFL);
        if (flags & O_NONBLOCK)
                return;
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
}

void FAST_FUNC ndelay_off(int fd)
{
        int flags = fcntl(fd, F_GETFL);
        if (!(flags & O_NONBLOCK))
                return;
        fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
}

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.
 */
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, 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;
}

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;
}