xrdp/common/string_calls.c

/**
 * xrdp: A Remote Desktop Protocol server.
 *
 * Copyright (C) Jay Sorg 2004-2020
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * generic string handling calls
 */

#if defined(HAVE_CONFIG_H)
#include "config_ac.h"
#endif
#include <signal.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <ctype.h>

#include "log.h"
#include "os_calls.h"
#include "string_calls.h"
#include "defines.h"
#include "unicode_defines.h"

unsigned int
g_format_info_string(char *dest, unsigned int len,
                     const char *format,
                     const struct info_string_tag map[])
{
    unsigned int result = 0;
    const char *copy_from;  /* Data to add to output */
    unsigned int copy_len;  /* Length of above */
    unsigned int skip;      /* Date to skip over in format string */
    const char *p;
    const struct info_string_tag *m;

    for ( ; *format != '\0'; format += skip)
    {
        if (*format == '%')
        {
            char ch = *(format + 1);
            if (ch == '%')
            {
                /* '%%' in format - replace with single '%' */
                copy_from = format;
                copy_len = 1;
                skip = 2;
            }
            else if (ch == '\0')
            {
                /* Percent at end of string - ignore */
                copy_from = NULL;
                copy_len = 0;
                skip = 1;
            }
            else
            {
                /* Look up the character in the map, assuming failure */
                copy_from = NULL;
                copy_len = 0;
                skip = 2;

                for (m = map ; m->ch != '\0' ; ++m)
                {
                    if (ch == m->ch)
                    {
                        copy_from = m->val;
                        copy_len = strlen(copy_from);
                        break;
                    }
                }
            }
        }
        else if ((p = strchr(format, '%')) != NULL)
        {
            /* Copy up to the next '%' */
            copy_from = format;
            copy_len = p - format;
            skip = copy_len;
        }
        else
        {
            /* Copy the rest of the format string */
            copy_from = format;
            copy_len = strlen(format);
            skip = copy_len;
        }

        /* Update the result before any truncation */
        result += copy_len;

        /* Do we have room in the output buffer for any more data? We
         * must always write a terminator if possible */
        if (len > 1)
        {
            if (copy_len > (len - 1))
            {
                copy_len = len - 1;
            }
            memcpy(dest, copy_from, copy_len);
            dest += copy_len;
            len -= copy_len;
        }
    }

    /* Room for a terminator? */
    if (len > 0)
    {
        *dest = '\0';
    }

    return result;
}

/******************************************************************************/
const char *
g_bool2text(int value)
{
    return value ? "true" : "false";
}

/*****************************************************************************/
int
g_text2bool(const char *s)
{
    if ( (g_atoi(s) != 0) ||
            (0 == g_strcasecmp(s, "true")) ||
            (0 == g_strcasecmp(s, "on")) ||
            (0 == g_strcasecmp(s, "yes")))
    {
        return 1;
    }
    return 0;
}

/*****************************************************************************/
int
g_get_display_num_from_display(const char *display_text)
{
    int rv = -1;
    const char *p;

    /* Skip over the hostname part of the DISPLAY */
    if (display_text != NULL && (p = strchr(display_text, ':')) != NULL)
    {
        ++p; /* Skip the ':' */

        /* Cater for the (still supported) double-colon. See
         * https://www.x.org/releases/X11R7.7/doc/libX11/libX11/libX11.html */
        if (*p == ':')
        {
            ++p;
        }

        /* Check it starts with a digit, to avoid oddities like DISPLAY=":zz.0"
         * being parsed successfully */
        if (isdigit(*p))
        {
            rv = g_atoi(p);
        }
    }

    return rv;
}

/*****************************************************************************/
/* returns length of text */
int
g_strlen(const char *text)
{
    if (text == NULL)
    {
        return 0;
    }

    return strlen(text);
}

/*****************************************************************************/
/* locates char in text */
char *
g_strchr(const char *text, int c)
{
    if (text == NULL)
    {
        return 0;
    }

    /* Cast needed to compile with C++ */
    return (char *)strchr(text, c);
}

/*****************************************************************************/
/* locates char in text */
char *
g_strrchr(const char *text, int c)
{
    if (text == NULL)
    {
        return 0;
    }

    /* Cast needed to compile with C++ */
    return (char *)strrchr(text, c);
}

/*****************************************************************************/
/* locates char in text with length */
char *
g_strnchr(const char *text, int c, int len)
{
    if (text == NULL || len <= 0)
    {
        return NULL;
    }

    return (char *)memchr(text, c, len);
}

/*****************************************************************************/
/* returns dest */
char *
g_strcpy(char *dest, const char *src)
{
    if (src == 0 && dest != 0)
    {
        dest[0] = 0;
        return dest;
    }

    if (dest == 0 || src == 0)
    {
        return 0;
    }

    return strcpy(dest, src);
}

/*****************************************************************************/
/* returns dest */
char *
g_strncpy(char *dest, const char *src, int len)
{
    char *rv;

    if (src == 0 && dest != 0)
    {
        dest[0] = 0;
        return dest;
    }

    if (dest == 0 || src == 0)
    {
        return 0;
    }

    rv = strncpy(dest, src, len);
    dest[len] = 0;
    return rv;
}

/*****************************************************************************/
/* returns dest */
char *
g_strcat(char *dest, const char *src)
{
    if (dest == 0 || src == 0)
    {
        return dest;
    }

    return strcat(dest, src);
}

/*****************************************************************************/
/* returns dest */
char *
g_strncat(char *dest, const char *src, int len)
{
    if (dest == 0 || src == 0)
    {
        return dest;
    }

    return strncat(dest, src, len);
}

/*****************************************************************************/
/* if in = 0, return 0 else return newly alloced copy of in */
char *
g_strdup(const char *in)
{
    int len;
    char *p;

    if (in == 0)
    {
        return 0;
    }

    len = g_strlen(in);
    p = (char *)g_malloc(len + 1, 0);

    if (p != NULL)
    {
        g_strcpy(p, in);
    }

    return p;
}

/*****************************************************************************/
/* if in = 0, return 0 else return newly alloced copy of input string
 * if the input string is larger than maxlen the returned string will be
 * truncated. All strings returned will include null termination*/
char *
g_strndup(const char *in, const unsigned int maxlen)
{
    unsigned int len;
    char *p;

    if (in == 0)
    {
        return 0;
    }

    len = g_strlen(in);

    if (len > maxlen)
    {
        len = maxlen - 1;
    }

    p = (char *)g_malloc(len + 2, 0);

    if (p != NULL)
    {
        g_strncpy(p, in, len + 1);
    }

    return p;
}

/*****************************************************************************/
int
g_strcmp(const char *c1, const char *c2)
{
    return strcmp(c1, c2);
}

/*****************************************************************************/
int
g_strncmp(const char *c1, const char *c2, int len)
{
    return strncmp(c1, c2, len);
}

/*****************************************************************************/
/* compare up to delim */
int
g_strncmp_d(const char *s1, const char *s2, const char delim, int n)
{
    char c1;
    char c2;

    c1 = 0;
    c2 = 0;
    while (n > 0)
    {
        c1 = *(s1++);
        c2 = *(s2++);
        if ((c1 == 0) || (c1 != c2) || (c1 == delim) || (c2 == delim))
        {
            return c1 - c2;
        }
        n--;
    }
    return c1 - c2;
}

/*****************************************************************************/
int
g_strcasecmp(const char *c1, const char *c2)
{
#if defined(_WIN32)
    return stricmp(c1, c2);
#else
    return strcasecmp(c1, c2);
#endif
}

/*****************************************************************************/
int
g_strncasecmp(const char *c1, const char *c2, int len)
{
#if defined(_WIN32)
    return strnicmp(c1, c2, len);
#else
    return strncasecmp(c1, c2, len);
#endif
}

/*****************************************************************************/
int
g_atoi(const char *str)
{
    if (str == 0)
    {
        return 0;
    }

    return atoi(str);
}

/*****************************************************************************/
/* As g_atoi() but allows for hexadecimal too */
int
g_atoix(const char *str)
{
    int base = 10;
    if (str == NULL)
    {
        str = "0";
    }

    while (isspace(*str))
    {
        ++str;
    }

    if (*str == '0' && tolower(*(str + 1)) == 'x')
    {
        str += 2;
        base = 16;
    }
    return strtol(str, NULL, base);
}

/*****************************************************************************/
int
g_htoi(char *str)
{
    int len;
    int index;
    int rv;
    int val;
    int shift;

    rv = 0;
    len = strlen(str);
    index = len - 1;
    shift = 0;

    while (index >= 0)
    {
        val = 0;

        switch (str[index])
        {
            case '1':
                val = 1;
                break;
            case '2':
                val = 2;
                break;
            case '3':
                val = 3;
                break;
            case '4':
                val = 4;
                break;
            case '5':
                val = 5;
                break;
            case '6':
                val = 6;
                break;
            case '7':
                val = 7;
                break;
            case '8':
                val = 8;
                break;
            case '9':
                val = 9;
                break;
            case 'a':
            case 'A':
                val = 10;
                break;
            case 'b':
            case 'B':
                val = 11;
                break;
            case 'c':
            case 'C':
                val = 12;
                break;
            case 'd':
            case 'D':
                val = 13;
                break;
            case 'e':
            case 'E':
                val = 14;
                break;
            case 'f':
            case 'F':
                val = 15;
                break;
        }

        rv = rv | (val << shift);
        index--;
        shift += 4;
    }

    return rv;
}

/*****************************************************************************/
/* returns number of bytes copied into out_str */
int
g_bytes_to_hexstr(const void *bytes, int num_bytes, char *out_str,
                  int bytes_out_str)
{
    int rv;
    int index;
    char *lout_str;
    const tui8 *lbytes;

    rv = 0;
    lbytes = (const tui8 *) bytes;
    lout_str = out_str;
    for (index = 0; index < num_bytes; index++)
    {
        if (bytes_out_str < 3)
        {
            break;
        }
        g_snprintf(lout_str, bytes_out_str, "%2.2x", lbytes[index]);
        lout_str += 2;
        bytes_out_str -= 2;
        rv += 2;
    }
    return rv;
}

/*****************************************************************************/
/* convert a byte array into a hex dump */
char *
g_bytes_to_hexdump(const char *src, int len)
{
    unsigned char *line;
    int i;
    int dump_number_lines;
    int dump_line_length;
    int dump_length;
    int dump_offset;
    int thisline;
    int offset;
    char *dump_buffer;

#define HEX_DUMP_SOURCE_BYTES_PER_LINE (16)
#ifdef _WIN32
#define HEX_DUMP_NEWLINE_SIZE (2)
#else
#ifdef _MACOS
#define HEX_DUMP_NEWLINE_SIZE (1)
#else
#define HEX_DUMP_NEWLINE_SIZE (1)
#endif
#endif

    dump_line_length = (4 + 3             /* = 4 offset + 3 space */
                        + ((2 + 1) * HEX_DUMP_SOURCE_BYTES_PER_LINE)  /* + (2 hex char + 1 space) per source byte */
                        + 2 /* + 2 space */
                        + HEX_DUMP_SOURCE_BYTES_PER_LINE
                        + HEX_DUMP_NEWLINE_SIZE);

    dump_number_lines = (len / HEX_DUMP_SOURCE_BYTES_PER_LINE) + 1; /* +1 to round up */
    dump_length = (dump_number_lines * dump_line_length   /* hex dump lines */
                   + 1);    /* terminating NULL */
    dump_buffer = (char *)g_malloc(dump_length, 1);
    if (dump_buffer == NULL)
    {
        LOG_DEVEL(LOG_LEVEL_WARNING,
                  "Failed to allocate buffer for hex dump of size %d",
                  dump_length);
        return NULL;
    }

    line = (unsigned char *)src;
    offset = 0;
    dump_offset = 0;

    while (offset < len)
    {
        g_sprintf(dump_buffer + dump_offset, "%04x   ", offset);
        dump_offset += 7;
        thisline = len - offset;

        if (thisline > HEX_DUMP_SOURCE_BYTES_PER_LINE)
        {
            thisline = HEX_DUMP_SOURCE_BYTES_PER_LINE;
        }

        for (i = 0; i < thisline; i++)
        {
            g_sprintf(dump_buffer + dump_offset, "%02x ", line[i]);
            dump_offset += 3;
        }

        for (; i < HEX_DUMP_SOURCE_BYTES_PER_LINE; i++)
        {
            dump_buffer[dump_offset++] = ' ';
            dump_buffer[dump_offset++] = ' ';
            dump_buffer[dump_offset++] = ' ';
        }

        dump_buffer[dump_offset++] = ' ';
        dump_buffer[dump_offset++] = ' ';

        for (i = 0; i < thisline; i++)
        {
            dump_buffer[dump_offset++] = (line[i] >= 0x20 && line[i] < 0x7f) ? line[i] : '.';
        }

        for (; i < HEX_DUMP_SOURCE_BYTES_PER_LINE; i++)
        {
            dump_buffer[dump_offset++] = ' ';
        }

#ifdef _WIN32
        dump_buffer[dump_offset++] = '\r';
        dump_buffer[dump_offset++] = '\n';
#else
#ifdef _MACOS
        dump_buffer[dump_offset++] = '\r';
#else
        dump_buffer[dump_offset++] = '\n';
#endif
#endif
        offset += thisline;
        line += thisline;


        if (dump_offset % dump_line_length != 0)
        {
            LOG_DEVEL(LOG_LEVEL_WARNING,
                      "BUG: dump_offset (%d) at the end of a line is not a "
                      "multiple of the line length (%d)",
                      dump_offset, dump_line_length);
        }

    }
    if (dump_offset > dump_length)
    {
        LOG_DEVEL(LOG_LEVEL_WARNING,
                  "BUG: dump_offset (%d) is larger than the dump_buffer length (%d)",
                  dump_offset, dump_length);
        dump_buffer[0] = '\0';
        return dump_buffer;
    }

    /* replace the last new line with the end of the string since log_message
       will add a new line */
    dump_buffer[dump_offset - HEX_DUMP_NEWLINE_SIZE] = '\0';
    return dump_buffer;
}

/*****************************************************************************/
int
g_pos(const char *str, const char *to_find)
{
    const char *pp;

    pp = strstr(str, to_find);

    if (pp == 0)
    {
        return -1;
    }

    return (pp - str);
}

/*****************************************************************************/

char *
g_strstr(const char *haystack, const char *needle)
{
    if (haystack == NULL || needle == NULL)
    {
        return NULL;
    }

    /* Cast needed to compile with C++ */
    return (char *)strstr(haystack, needle);
}

/*****************************************************************************/
/* returns error */
int
g_strtrim(char *str, int trim_flags)
{
    int rv = 0;
    int index;
    int j;

    switch (trim_flags)
    {
        case 4: /* trim through */

            j = 0;
            for (index = 0; str[index] != '\0'; index++)
            {
                if (str[index] > ' ')
                {
                    str[j++] = str[index];
                }
            }

            str[j] = '\0';
            break;

        case 3: /* trim both */
            rv = g_strtrim(str, 1) || g_strtrim(str, 2);
            break;

        case 2: /* trim right */
            index = strlen(str);
            while (index > 0 && str[index - 1] <= ' ')
            {
                --index;
            }
            str[index] = '\0';
            break;

        case 1: /* trim left */
            index = 0;
            while (str[index] != '\0' && str[index] <= ' ')
            {
                ++index;
            }
            if (index > 0)
            {
                memmove(str, str + index, strlen(str) + 1 - index);
            }
            break;

        default:
            rv = 1;
    }

    return rv;
}

/*****************************************************************************/
char *
g_strnjoin(char *dest, int dest_len, const char *joiner, const char *src[], int src_len)
{
    int len = 0;
    int joiner_len;
    int i = 0;
    int dest_remaining;
    char *dest_pos = dest;
    char *dest_end;

    if (dest == NULL || dest_len < 1)
    {
        return dest;
    }
    if (src == NULL || src_len < 1)
    {
        dest[0] = '\0';
        return dest;
    }

    dest[0] = '\0';
    dest_end = dest + dest_len - 1;
    joiner_len = g_strlen(joiner);
    for (i = 0; i < src_len - 1 && dest_pos < dest_end; i++)
    {
        len = g_strlen(src[i]);
        dest_remaining = dest_end - dest_pos;
        g_strncat(dest_pos, src[i], dest_remaining);
        dest_pos += MIN(len, dest_remaining);

        if (dest_pos < dest_end)
        {
            dest_remaining = dest_end - dest_pos;
            g_strncat(dest_pos, joiner, dest_remaining);
            dest_pos += MIN(joiner_len, dest_remaining);
        }
    }

    if (i == src_len - 1 && dest_pos < dest_end)
    {
        g_strncat(dest_pos, src[i], dest_end - dest_pos);
    }

    return dest;
}

/*****************************************************************************/
int
g_bitmask_to_str(int bitmask, const struct bitmask_string bitdefs[],
                 char delim, char *buff, int bufflen)
{
    int rlen = 0; /* Returned length */

    if (bufflen <= 0) /* Caller error */
    {
        rlen = -1;
    }
    else
    {
        char *p = buff;
        /* Find the last writeable character in the buffer */
        const char *last = buff + (bufflen - 1);

        const struct bitmask_string *b;

        for (b = &bitdefs[0] ; b->mask != 0; ++b)
        {
            if ((bitmask & b->mask) != 0)
            {
                if (p > buff)
                {
                    /* Not first item - append separator */
                    if (p < last)
                    {
                        *p++ = delim;
                    }
                    ++rlen;
                }

                int slen = g_strlen(b->str);
                int copylen = MIN(slen, last - p);
                g_memcpy(p, b->str, copylen);
                p += copylen;
                rlen += slen;

                /* Remove the bit so we can check for undefined bits later*/
                bitmask &= ~b->mask;
            }
        }

        if (bitmask != 0)
        {
            /* Bits left which aren't named by the user */
            if (p > buff)
            {
                if (p < last)
                {
                    *p++ = delim;
                }
                ++rlen;
            }
            /* This call will terminate the return buffer */
            rlen += g_snprintf(p, last - p + 1, "0x%x", bitmask);
        }
        else
        {
            *p = '\0';
        }
    }

    return rlen;
}

/*****************************************************************************/
int
g_str_to_bitmask(const char *str, const struct bitmask_string bitdefs[],
                 const char *delim, char *unrecognised, int unrecognised_len)
{
    char *properties = NULL;
    char *p = NULL;
    int mask = 0;

    if (unrecognised_len < 1)
    {
        /* No space left to tell unrecognised tokens */
        return 0;
    }
    if (!unrecognised)
    {
        return 0;
    }
    /* ensure not to return with uninitialized buffer */
    unrecognised[0] = '\0';
    if (!str || !bitdefs || !delim)
    {
        return 0;
    }
    properties = g_strdup(str);
    if (!properties)
    {
        return 0;
    }
    p = strtok(properties, delim);
    while (p != NULL)
    {
        g_strtrim(p, 3);
        const struct bitmask_string *b;
        int found = 0;
        for (b = &bitdefs[0] ; b->str != NULL; ++b)
        {
            if (0 == g_strcasecmp(p, b->str))
            {
                mask |= b->mask;
                found = 1;
                break;
            }
        }
        if (found == 0)
        {
            int length = g_strlen(unrecognised);
            if (length > 0)
            {
                /* adding ",property" */
                if (length + g_strlen(p) + 1 < unrecognised_len)
                {
                    unrecognised[length] = delim[0];
                    length += 1;
                    g_strcpy(unrecognised + length, p);
                }
            }
            else if (g_strlen(p) < unrecognised_len)
            {
                g_strcpy(unrecognised, p);
            }
        }
        p = strtok(NULL, delim);
    }

    g_free(properties);
    return mask;
}

/*****************************************************************************/
int
g_bitmask_to_charstr(int bitmask, const struct bitmask_char bitdefs[],
                     char *buff, int bufflen, int *rest)
{
    int rlen = 0; /* Returned length */

    if (bufflen <= 0) /* Caller error */
    {
        rlen = -1;
    }
    else
    {
        char *p = buff;
        /* Find the last writeable character in the buffer */
        const char *last = buff + (bufflen - 1);

        const struct bitmask_char *b;

        for (b = &bitdefs[0] ; b->c != '\0'; ++b)
        {
            if ((bitmask & b->mask) != 0)
            {
                if (p < last)
                {
                    *p++ = b->c;
                }
                ++rlen;

                /* Remove the bit so we don't report it back */
                bitmask &= ~b->mask;
            }
        }
        *p = '\0';

        if (rest != NULL)
        {
            *rest = bitmask;
        }
    }

    return rlen;
}

/*****************************************************************************/
int
g_charstr_to_bitmask(const char *str, const struct bitmask_char bitdefs[],
                     char *unrecognised, int unrecognised_len)
{
    int bitmask = 0;
    const char *cp;
    int j = 0;

    if (str != NULL && bitdefs != NULL)
    {
        for (cp = str ; *cp != '\0' ; ++cp)
        {
            const struct bitmask_char *b;
            char c = toupper(*cp);

            for (b = &bitdefs[0] ; b->c != '\0'; ++b)
            {
                if (toupper(b->c) == c)
                {
                    bitmask |= b->mask;
                    break;
                }
            }
            if (b->c == '\0')
            {
                if (unrecognised != NULL && j < (unrecognised_len - 1))
                {
                    unrecognised[j++] = *cp;
                }
            }
        }
    }

    if (unrecognised != NULL && j < unrecognised_len)
    {
        unrecognised[j] = '\0';
    }

    return bitmask;
}

/*****************************************************************************/
/*
 * Looks for a simple mapping of signal number to name
 */
static const char *
find_sig_name(int signum)
{
    typedef struct
    {
        int num;
        const char *name;
    } sig_to_name_type;

    // Map a string 'zzz' to { SIGzzz, "zzz"} for making
    // typo-free sig_to_name_type objects
#   define DEFSIG(sig) { SIG ## sig, # sig }

    // Entries in this array are taken from
    // The Single UNIX ® Specification, Version 2 (1997)
    // plus additions from specific operating systems.
    //
    // The SUS requires these to be positive integer constants with a
    // macro definition.  Note that SIGRTMIN and SIGRTMAX on Linux are
    // NOT constants, so have to be handled separately.
    static const sig_to_name_type sigmap[] =
    {
        // Names from SUS v2, in the order they are listed in that document
        // that *should* be defined everywhere
        //
        // Commented out definitions below are NOT used everywhere
        DEFSIG(ABRT), DEFSIG(ALRM), DEFSIG(FPE), DEFSIG(HUP),
        DEFSIG(ILL), DEFSIG(INT), DEFSIG(KILL), DEFSIG(PIPE),
        DEFSIG(QUIT), DEFSIG(SEGV), DEFSIG(TERM), DEFSIG(USR1),
        DEFSIG(USR2), DEFSIG(CHLD), DEFSIG(CONT), DEFSIG(STOP),
        DEFSIG(TSTP), DEFSIG(TTIN), DEFSIG(TTOU), DEFSIG(BUS),
        /* DEFSIG(POLL), */ /* DEFSIG(PROF), */ DEFSIG(SYS), DEFSIG(TRAP),
        DEFSIG(URG), DEFSIG(VTALRM), DEFSIG(XCPU), DEFSIG(XFSZ),

        // SIGPOLL and SIGPROF are marked as obselescent in 1003.1-2017,
        // Also SIGPOLL isn't in *BSD operating systems which use SIGIO
#ifdef SIGPOLL
        DEFSIG(POLL),
#endif
#ifdef SIGPROF
        DEFSIG(PROF),
#endif

        // BSD signals (from FreeBSD/OpenBSD sys/signal.h and
        // Darwin/Illumos signal.h)
#ifdef SIGEMT
        DEFSIG(EMT),
#endif
#ifdef SIGIO
        DEFSIG(IO),
#endif
#ifdef SIGWINCH
        DEFSIG(WINCH),
#endif
#ifdef SIGINFO
        DEFSIG(INFO),
#endif
#ifdef SIGTHR
        DEFSIG(THR),
#endif
#ifdef SIGLIBRT
        DEFSIG(LIBRT),
#endif
#ifdef SIGPWR
        DEFSIG(PWR),
#endif
#ifdef SIGWAITING
        DEFSIG(WAITING),
#endif
#ifdef SIGLWP
        DEFSIG(LWP),
#endif

        // Linux additions to *BSD (signal(7))
#ifdef SIGLOST
        DEFSIG(LOST),
#endif
#ifdef SIGSTKFLT
        DEFSIG(STKFLT),
#endif

        // Terminator
        {0, NULL}
#undef DEFSIG
    };

    const sig_to_name_type *p;

    for (p = &sigmap[0] ; p->name != NULL ; ++p)
    {
        if (p->num == signum)
        {
            return p->name;
        }
    }

    // These aren't constants on Linux
#ifdef SIGRTMIN
    if (signum == SIGRTMIN)
    {
        return "RTMIN";
    }
#endif
#ifdef SIGRTMAX
    if (signum == SIGRTMAX)
    {
        return "RTMAX";
    }
#endif

    return NULL;
}

/*****************************************************************************/
char *
g_sig2text(int signum, char sigstr[])
{
    if (signum >= 0)
    {
        const char *name = find_sig_name(signum);

        if (name != NULL)
        {
            g_snprintf(sigstr, MAXSTRSIGLEN, "SIG%s", name);
            return sigstr;
        }

#if defined(SIGRTMIN) && defined(SIGRTMAX)
        if (signum > SIGRTMIN && signum < SIGRTMAX)
        {
            g_snprintf(sigstr, MAXSTRSIGLEN, "SIGRTMIN+%d", signum - SIGRTMIN);
            return sigstr;
        }
#endif
    }

    // If all else fails...
    g_snprintf(sigstr, MAXSTRSIGLEN, "SIG#%d", signum);
    return sigstr;
}

/*****************************************************************************/
char32_t
utf8_get_next_char(const char **utf8str_ref, unsigned int *len_ref)
{
    /*
     * Macro used to parse a continuation character
     * @param cp Character Pointer (incremented on success)
     * @param end One character past end of input string
     * @param value The value we're constructing
     * @param finish_label Where to go in the event of an error */
#define PARSE_CONTINUATION_CHARACTER(cp, end, value, finish_label) \
    { \
        /* Error if we're out of data, or this char isn't a continuation */ \
        if (cp == end || !IS_VALID_CONTINUATION_CHAR(*cp)) \
        { \
            value = UCS_REPLACEMENT_CHARACTER; \
            goto finish_label; \
        } \
        value = (value) << 6 | (*cp & 0x3f); \
        ++cp; \
    }

    char32_t rv;

    /* Easier to work with unsigned chars and no indirection */
    const unsigned char *cp = (const unsigned char *)*utf8str_ref;
    const unsigned char *end = (len_ref != NULL) ? cp + *len_ref : cp + 6;

    if (cp == end)
    {
        return 0; // Pathological case
    }

    unsigned int c0 = *cp++;

    if (c0 < 0x80)
    {
        rv = c0;
    }
    else if (c0 < 0xc0)
    {
        /* Unexpected continuation character */
        rv = UCS_REPLACEMENT_CHARACTER;
    }
    else if (c0 < 0xe0)
    {
        /* Valid start character for sequence of length 2
         * U-00000080 – U-000007FF */
        rv = (c0 & 0x1f);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);

        if (rv < 0x80 || INVALID_UNICODE_80_TO_7FF(rv))
        {
            rv = UCS_REPLACEMENT_CHARACTER;
        }
    }
    else if (c0 < 0xf0)
    {
        /* Valid start character for sequence of length 3
         *  U-00000800 – U-0000FFFF */
        rv = (c0 & 0xf);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        if (rv < 0x800 || INVALID_UNICODE_800_TO_FFFF(rv))
        {
            rv = UCS_REPLACEMENT_CHARACTER;
        }
    }
    else if (c0 < 0xf8)
    {
        /* Valid start character for sequence of length 4
         * U-00010000 – U-0001FFFFF */
        rv = (c0 & 0x7);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        if (rv < 0x10000 || INVALID_UNICODE_10000_TO_1FFFFF(rv))
        {
            rv = UCS_REPLACEMENT_CHARACTER;
        }
    }
    else if (c0 < 0xfc)
    {
        /* Valid start character for sequence of length 5
         * U-00200000 – U-03FFFFFF */
        rv = (c0 & 0x3);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);

        // These values are currently unsupported
        rv = UCS_REPLACEMENT_CHARACTER;
    }

    else if (c0 < 0xfe)
    {
        /* Valid start character for sequence of length 6
         * U-04000000 – U-7FFFFFFF */
        rv = (c0 & 0x1);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);
        PARSE_CONTINUATION_CHARACTER(cp, end, rv, finish);

        // These values are currently unsupported
        rv = UCS_REPLACEMENT_CHARACTER;
    }
    else
    {
        // Invalid characters
        rv = UCS_REPLACEMENT_CHARACTER;
    }

finish:

    if (len_ref)
    {
        *len_ref -= ((const char *)cp - *utf8str_ref);
    }
    *utf8str_ref = (const char *)cp;

    return rv;
#undef PARSE_CONTINUATION_CHARACTER
}

/*****************************************************************************/
unsigned int
utf_char32_to_utf8(char32_t c32, char *u8str)
{
    unsigned int rv;

    if (INVALID_UNICODE(c32))
    {
        c32 = UCS_REPLACEMENT_CHARACTER;
    }

    if (c32 < 0x80)
    {
        rv = 1;
        if (u8str != NULL)
        {
            u8str[0] = (char)c32;
        }
    }
    else if (c32 < 0x800)
    {
        rv = 2;
        // 11 bits. Five in first byte, six in second
        if (u8str != NULL)
        {
            u8str[1] = (c32 & 0x3f) | 0x80;
            c32 >>= 6;
            u8str[0] = (c32 & 0x1f) | 0xc0;
        }
    }
    else if (c32 < 0xffff)
    {
        rv = 3;
        // 16 bits. Four in first byte, six in second and third
        if (u8str != NULL)
        {
            u8str[2] = (c32 & 0x3f) | 0x80;
            c32 >>= 6;
            u8str[1] = (c32 & 0x3f) | 0x80;
            c32 >>= 6;
            u8str[0] = (c32 & 0xf) | 0xe0;
        }
    }
    else
    {
        rv = 4;
        // 21 bits. Three in first byte, six in second, third and fourth
        if (u8str != NULL)
        {
            u8str[3] = (c32 & 0x3f) | 0x80;
            c32 >>= 6;
            u8str[2] = (c32 & 0x3f) | 0x80;
            c32 >>= 6;
            u8str[1] = (c32 & 0x3f) | 0x80;
            c32 >>= 6;
            u8str[0] = (c32 & 0x7) | 0xf0;
        }
    }

    return rv;
}

/*****************************************************************************/
unsigned int
utf8_char_count(const char *utf8str)
{
    unsigned int rv = 0;
    char32_t c;

    if (utf8str != NULL)
    {
        while ((c = utf8_get_next_char(&utf8str, NULL)) != 0)
        {
            ++rv;
        }
    }

    return rv;
}

/*****************************************************************************/
unsigned int
utf8_as_utf16_word_count(const char *utf8str, unsigned int len)
{
    unsigned int rv = 0;
    while (len > 0)
    {
        char32_t c = utf8_get_next_char(&utf8str, &len);
        // Characters not in the BMP (i.e. over 0xffff) need a high/low
        // surrogate pair
        rv += (c >= 0x10000) ? 2 : 1;
    }

    return rv;
}

/*****************************************************************************/
int
utf8_add_char_at(char *utf8str, unsigned int len, char32_t c32,
                 unsigned int index)
{
    int rv = 0;

    char c8[MAXLEN_UTF8_CHAR];
    unsigned int c8len = utf_char32_to_utf8(c32, c8);

    // Find out where to insert the character
    char *insert_pos = utf8str;

    while (index > 0 && *insert_pos != '\0')
    {
        utf8_get_next_char((const char **)&insert_pos, NULL);
        --index;
    }

    // Did we get to where we need to be?
    if (index == 0)
    {
        unsigned int bytes_to_move = strlen(insert_pos) + 1; // Include terminator
        // Is there room to insert the character?
        //
        //  <----------- len ---------->
        //            <--> (bytes_to_move)
        // +----------------------------+
        // |ABCDEFGHIJLMN\0             |
        // +----------------------------+
        //  ^         ^
        //  +-utf8str +-insert_pos
        //
        if ((insert_pos - utf8str) + bytes_to_move + c8len <= len)
        {
            memmove(insert_pos + c8len, insert_pos, bytes_to_move);
            memcpy(insert_pos, c8, c8len);
            rv = 1;
        }
    }

    return rv;
}

/*****************************************************************************/
char32_t
utf8_remove_char_at(char *utf8str, unsigned int index)
{
    int rv = 0;

    // Find out where to remove the character
    char *remove_pos = utf8str;

    while (index > 0)
    {
        // Any characters left in string?
        if (*remove_pos == '\0')
        {
            break;
        }

        utf8_get_next_char((const char **)&remove_pos, NULL);
        --index;
    }

    // Did we get to where we need to be?
    if (index == 0)
    {
        // Find the position after the character
        char *after_pos = remove_pos;
        rv = utf8_get_next_char((const char **)&after_pos, NULL);

        // Move everything up
        memmove(remove_pos, after_pos, strlen(after_pos) + 1);
    }

    return rv;
}