/* $OpenBSD: strerror_r.c,v 1.13 2016/10/19 16:26:16 bluhm Exp $ */
/* Public Domain <marc@snafu.org> */

#include <errno.h>
#include <limits.h>
#include <signal.h>
#include <string.h>

static size_t
__digits10(unsigned int num)
{
        size_t i = 0;

        do {
                num /= 10;
                i++;
        } while (num != 0);

        return i;
}

static int
__itoa(int num, int sign, char *buffer, size_t start, size_t end)
{
        size_t pos;
        unsigned int a;
        int neg;

        if (sign && num < 0) {
                a = -num;
                neg = 1;
        }
        else {
                a = num;
                neg = 0;
        }

        pos = start + __digits10(a);
        if (neg)
            pos++;

        if (pos < end)
                buffer[pos] = '\0';
        else
                return ERANGE;
        pos--;
        do {
                buffer[pos] = (a % 10) + '0';
                pos--;
                a /= 10;
        } while (a != 0);
        if (neg)
                buffer[pos] = '-';
        return 0;
}


static int
__num2string(int num, int sign, int setid, char *buf, size_t buflen,
    const char * const list[], size_t max, const char *def)
{
        int ret = 0;
        size_t len;

        if (0 <= num && num < max) {
                len = strlcpy(buf, list[num], buflen);
                if (len >= buflen)
                        ret = ERANGE;
        } else {
                len = strlcpy(buf, def, buflen);
                if (len >= buflen)
                        ret = ERANGE;
                else {
                        ret = __itoa(num, sign, buf, len, buflen);
                        if (ret == 0)
                                ret = EINVAL;
                }
        }

        return ret;
}

#define UPREFIX "Unknown error: "

int
strerror_r(int errnum, char *strerrbuf, size_t buflen)
{
        int ret_errno;

        ret_errno = __num2string(errnum, 1, 1, strerrbuf, buflen,
            sys_errlist, sys_nerr, UPREFIX);

        if (ret_errno)
                errno = ret_errno;
        return (ret_errno);
}
DEF_WEAK(strerror_r);

#define USIGPREFIX "Unknown signal: "

char *
__strsignal(int num, char *buf)
{
        __num2string(num, 0, 2, buf, NL_TEXTMAX, sys_siglist, NSIG,
            USIGPREFIX);
        return buf;
}