/* Copyright (C) 2001-2021 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/* Unix-specific routines for Ghostscript */

#ifdef __MINGW32__
#  include "windows_.h"
#endif
#include "errno_.h"
#include "pipe_.h"
#include "string_.h"
#include "time_.h"
#include "gx.h"
#include "gsexit.h"
#include "gp.h"

#ifdef HAVE_FONTCONFIG
#  include <fontconfig/fontconfig.h>
#endif

/*
 * This is the only place in Ghostscript that calls 'exit'.  Including
 * <stdlib.h> is overkill, but that's where it's declared on ANSI systems.
 * We don't have any way of detecting whether we have a standard library
 * (some GNU compilers perversely define __STDC__ but don't provide
 * an ANSI-compliant library), so we check __PROTOTYPES__ and
 * hope for the best.  We pick up getenv at the same time.
 */
#ifdef __PROTOTYPES__
#  include <stdlib.h>           /* for exit and getenv */
#else
extern void exit(int);
extern char *getenv(const char *);
#endif

#ifdef GS_DEVS_SHARED
#ifndef GS_DEVS_SHARED_DIR
#  define GS_DEVS_SHARED_DIR "/usr/lib/ghostscript/8.16"
#endif
/*
 * use shared library for drivers, always load them when starting, this
 * avoid too many modifications, and since it is supported only under linux
 * and applied as a patch (preferable).
 */
#include <sys/types.h>
#include <dirent.h>
#include <dlfcn.h>
#include <string.h>

void
gp_init(void)
{
  DIR*           dir = NULL;
  struct dirent* dirent;
  char           buff[1024];
  char*          pbuff;
  void*          handle;
  void           (*gs_shared_init)(void);

  strncpy(buff, GS_DEVS_SHARED_DIR, sizeof(buff) - 2);
  pbuff = buff + strlen(buff);
  *pbuff++ = '/'; *pbuff = '\0';

  dir = opendir(GS_DEVS_SHARED_DIR);
  if (dir == 0) return;

  while ((dirent = readdir(dir)) != 0) {
    strncpy(pbuff, dirent->d_name, sizeof(buff) - (pbuff - buff) - 1);
    if ((handle = dlopen(buff, RTLD_NOW)) != 0) {
      if ((gs_shared_init = dlsym(handle, "gs_shared_init")) != 0) {
        (*gs_shared_init)();
      } else {
      }
    }
  }

  closedir(dir);
}
#else
/* Do platform-dependent initialization. */
void
gp_init(void)
{
}
#endif

/* Do platform-dependent cleanup. */
void
gp_exit(int exit_status, int code)
{
}

/* Exit the program. */
void
gp_do_exit(int exit_status)
{
    exit(exit_status);
}

/* ------ Miscellaneous ------ */

/* Get the string corresponding to an OS error number. */
const char *
gp_strerror(int errnum)
{
#ifdef HAVE_STRERROR
    return strerror(errnum);
#else
    return NULL;
#endif
}

/* We don't have a good way to get a serial number here, so just */
/* return what we always used to: GS_SERIALNUMBER. */
int
gp_serialnumber(void)
{
    return (int)(gs_serialnumber);
}

/* read in a MacOS 'resource' from an extended attribute. */
/* we don't try to implemented this since it requires support */
/* for Apple's HFS(+) filesystem */
int
gp_read_macresource(byte *buf, const char *filename,
                    const uint type, const ushort id)
{
    return 0;
}

/* ------ Date and time ------ */

/* Read the current time (in seconds since Jan. 1, 1970) */
/* and fraction (in nanoseconds). */
void
gp_get_realtime(long *pdt)
{
    struct timeval tp;
    const char *env;

#if gettimeofday_no_timezone    /* older versions of SVR4 */
    {
        if (gettimeofday(&tp) == -1) {
            lprintf("Ghostscript: gettimeofday failed!\n");
            tp.tv_sec = tp.tv_usec = 0;
        }
    }
#else /* All other systems */
    {
        struct timezone tzp;

        if (gettimeofday(&tp, &tzp) == -1) {
            lprintf("Ghostscript: gettimeofday failed!\n");
            tp.tv_sec = tp.tv_usec = 0;
        }
    }
#endif

    env = getenv("SOURCE_DATE_EPOCH");
    if (env) {
        char *end;
        long timestamp;

        errno = 0;
        timestamp = strtol(env, &end, 10);
        if (env == end || *end || errno != 0) {
            lprintf("Ghostscript: SOURCE_DATE_EPOCH is not a number!\n");
            timestamp = 0;
        }

        tp.tv_sec = timestamp;
        tp.tv_usec = 0;

        /* We need to fix the environment timezone to get reproducible */
        /* results when parsing the result of gp_get_realtime. */
        setenv("TZ", "UTC", 1);
    }

    /* tp.tv_sec is #secs since Jan 1, 1970 */
    pdt[0] = tp.tv_sec;

    /* Some Unix systems (e.g., Interactive 3.2 r3.0) return garbage */
    /* in tp.tv_usec.  Try to filter out the worst of it here. */
    pdt[1] = tp.tv_usec >= 0 && tp.tv_usec < 1000000 ? tp.tv_usec * 1000 : 0;

#ifdef DEBUG_CLOCK
    printf("tp.tv_sec = %d  tp.tv_usec = %d  pdt[0] = %ld  pdt[1] = %ld\n",
           tp.tv_sec, tp.tv_usec, pdt[0], pdt[1]);
#endif
}

/* Read the current user CPU time (in seconds) */
/* and fraction (in nanoseconds).  */
void
gp_get_usertime(long *pdt)
{
#if use_times_for_usertime
    struct tms tms;
    long ticks;
    const long ticks_per_sec = CLK_TCK;

    times(&tms);
    ticks = tms.tms_utime + tms.tms_stime + tms.tms_cutime + tms.tms_cstime;
    pdt[0] = ticks / ticks_per_sec;
    pdt[1] = (ticks % ticks_per_sec) * (1000000000 / ticks_per_sec);
#else
    gp_get_realtime(pdt);       /* Use an approximation on other hosts.  */
#endif
}

/* ------ Screen management ------ */

/* Get the environment variable that specifies the display to use. */
const char *
gp_getenv_display(void)
{
    return getenv("DISPLAY");
}

/* ------ Printer accessing ------ */

extern gp_file *
gp_fopen_unix(const gs_memory_t *mem, const char *fname, const char *mode, int pipe);

/* Open a connection to a printer.  See gp.h for details. */
FILE *
gp_open_printer_impl(gs_memory_t *mem,
                     const char  *fname,
                     int         *binary_mode,
                     int          (**close)(FILE *))
{
#ifdef GS_NO_FILESYSTEM
    return NULL;
#else
    const char *fmode = (*binary_mode ? "wb" : "w");
    *close = fname[0] == '|' ? pclose : fclose;
    return gp_fopen_impl(mem, fname, fmode);
#endif
}

/* Close the connection to the printer. */
void
gp_close_printer(gp_file * pfile, const char *fname)
{
#ifndef GS_NO_FILESYSTEM
    gp_fclose(pfile);
#endif
}

/* ------ Font enumeration ------ */

 /* This is used to query the native os for a list of font names and
  * corresponding paths. The general idea is to save the hassle of
  * building a custom fontmap file.
  */

/* Mangle the FontConfig family and style information into a
 * PostScript font name */
#ifdef HAVE_FONTCONFIG
static void makePSFontName(char* family, int weight, int slant, char *buf, int bufsize)
{
    int bytesCopied, length, i;
    const char *slantname, *weightname;

    switch (slant) {
        case FC_SLANT_ROMAN:   slantname=""; break;;
        case FC_SLANT_OBLIQUE: slantname="Oblique"; break;;
        case FC_SLANT_ITALIC:  slantname="Italic"; break;;
        default:               slantname="Unknown"; break;;
    }

    switch (weight) {
        case FC_WEIGHT_MEDIUM:   weightname=""; break;;
        case FC_WEIGHT_LIGHT:    weightname="Light"; break;;
        case FC_WEIGHT_DEMIBOLD: weightname="Demi"; break;;
        case FC_WEIGHT_BOLD:     weightname="Bold"; break;;
        case FC_WEIGHT_BLACK:    weightname="Black"; break;;
        default:                 weightname="Unknown"; break;;
    }

    length = strlen(family);
    if (length >= bufsize)
        length = bufsize;
    /* Copy the family name, stripping spaces */
    bytesCopied=0;
    for (i = 0; i < length; i++)
        if (family[i] != ' ')
            buf[bytesCopied++] = family[i];

    if ( ((slant != FC_SLANT_ROMAN) || (weight != FC_WEIGHT_MEDIUM)) \
            && bytesCopied < bufsize )
    {
        buf[bytesCopied] = '-';
        bytesCopied++;
        if (weight != FC_WEIGHT_MEDIUM)
        {
            length = strlen(family);
            if ((length + bytesCopied) >= bufsize)
                length = bufsize - bytesCopied - 1;
            strncpy(buf+bytesCopied, weightname, length);
            bytesCopied += length;
        }
        if (slant != FC_SLANT_ROMAN)
        {
            length = strlen(family);
            if ((length + bytesCopied) >= bufsize)
                length = bufsize - bytesCopied - 1;
            strncpy(buf+bytesCopied, slantname, length);
            bytesCopied += length;
        }
    }
    buf[bytesCopied] = '\0';
}
#endif

/* State struct for font iteration
 * - passed as an opaque 'void*' through the rest of gs */
#ifdef HAVE_FONTCONFIG
typedef struct {
    int index;              /* current index of iteration over font_list */
    FcConfig* fc;           /* FontConfig library handle */
    FcFontSet* font_list;   /* FontConfig font list */
    char name[255];         /* name of last font */
    gs_memory_t *mem;       /* Memory pointer */
} unix_fontenum_t;
#endif

void *gp_enumerate_fonts_init(gs_memory_t *mem)
{
#ifdef HAVE_FONTCONFIG
    unix_fontenum_t *state;
    FcPattern *pat;
    FcObjectSet *os;
    FcStrList *fdirlist = NULL;
    FcChar8 *dirstr;
    int code;

    state = (unix_fontenum_t *)malloc(sizeof(unix_fontenum_t));
    if (state == NULL)
        return NULL;    /* Failed to allocate state */

    state->index     = 0;
    state->fc        = NULL;
    state->font_list = NULL;
    state->mem       = mem;

    /* Load the fontconfig library */
    state->fc = FcInitLoadConfigAndFonts();
    if (state->fc == NULL) {
        free(state);
        state = NULL;
        dmlprintf(mem, "destroyed state - fontconfig init failed");
        return NULL;  /* Failed to open fontconfig library */
    }

    fdirlist = FcConfigGetFontDirs(state->fc);
    if (fdirlist == NULL) {
        FcConfigDestroy(state->fc);
        free(state);
        return NULL;
    }

    /* We're going to trust what fontconfig tells us, and add it's known directories
     * to our permitted read paths
     */
    code = 0;
    while ((dirstr = FcStrListNext(fdirlist)) != NULL && code >= 0) {
        char dirstr2[gp_file_name_sizeof];
        dirstr2[0] = '\0';
        strncat(dirstr2, (char *)dirstr, gp_file_name_sizeof - 2);
        strncat(dirstr2, "/", gp_file_name_sizeof - 1);
        code = gs_add_control_path(mem, gs_permit_file_reading, (char *)dirstr2);
    }
    FcStrListDone(fdirlist);
    if (code < 0) {
        FcConfigDestroy(state->fc);
        free(state);
        return NULL;
    }

    /* load the font set that we'll iterate over */
    pat = FcPatternBuild(NULL,
            FC_OUTLINE, FcTypeBool, 1,
            FC_SCALABLE, FcTypeBool, 1,
#if defined(FC_MAJOR) && FC_MAJOR >= 2 && defined(FC_MINOR) && FC_MINOR >= 13
            FC_VARIABLE, FcTypeBool, 0,
#endif
            NULL);
    os = FcObjectSetBuild(FC_FILE, FC_OUTLINE,
            FC_FAMILY, FC_WEIGHT, FC_SLANT,
            NULL);
    /* We free the data allocated by FcFontList() when
    gp_enumerate_fonts_free() calls FcFontSetDestroy(), but FcFontSetDestroy()
    has been seen to leak blocks according to valgrind and asan. E.g. this can
    be seen by running:
        ./sanbin/gs -dNODISPLAY -dBATCH -dNOPAUSE -c "/A_Font findfont"
    */
    state->font_list = FcFontList(0, pat, os);
    FcPatternDestroy(pat);
    FcObjectSetDestroy(os);
    if (state->font_list == NULL) {
        free(state);
        state = NULL;
        return NULL;  /* Failed to generate font list */
    }
    return (void *)state;
#else
    return NULL;
#endif
}

int gp_enumerate_fonts_next(void *enum_state, char **fontname, char **path)
{
#ifdef HAVE_FONTCONFIG
    unix_fontenum_t* state = (unix_fontenum_t *)enum_state;
    FcChar8 *file_fc = NULL;
    FcChar8 *family_fc = NULL;
    int outline_fc, slant_fc, weight_fc;
    FcPattern *font;
    FcResult result;

    if (state == NULL) {
        return 0;   /* gp_enumerate_fonts_init failed for some reason */
    }

    /* We use the loop so we can skip over fonts that return errors */
    while(1) {
        if (state->index == state->font_list->nfont) {
            return 0; /* we've run out of fonts */
        }

        /* Bits of the following were borrowed from Red Hat's
         * fontconfig patch for Ghostscript 7 */
        font = state->font_list->fonts[state->index];
        state->index++;

        /* We do the FC_FILE first because this *should* never fail
         * and it gives us a string to use in later debug prints
         */
        result = FcPatternGetString (font, FC_FILE, 0, &file_fc);
        if (result != FcResultMatch || file_fc == NULL) {
            dmlprintf(state->mem, "DEBUG: FC_FILE mismatch\n");
            continue;
        }

        result = FcPatternGetString (font, FC_FAMILY, 0, &family_fc);
        if (result != FcResultMatch || family_fc == NULL) {
            dmlprintf1(state->mem, "DEBUG: FC_FAMILY mismatch in %s\n", (char *)file_fc);
            continue;
        }

        result = FcPatternGetBool (font, FC_OUTLINE, 0, &outline_fc);
        if (result != FcResultMatch) {
            dmlprintf2(state->mem, "DEBUG: FC_OUTLINE failed to match on %s in %s\n", (char*)family_fc, (char *)file_fc);
            continue;
        }

        result = FcPatternGetInteger (font, FC_SLANT, 0, &slant_fc);
        if (result != FcResultMatch) {
            dmlprintf1(state->mem, "DEBUG: FC_SLANT didn't match in %s\n", (char *)file_fc);
            continue;
        }

        result = FcPatternGetInteger (font, FC_WEIGHT, 0, &weight_fc);
        if (result != FcResultMatch) {
            dmlprintf1(state->mem, "DEBUG: FC_WEIGHT didn't match in %s\n", (char *)file_fc);
            continue;
        }
        break;
    }

    /* Gross hack to work around Fontconfig's inability to tell
     * us the font's PostScript name - generate it ourselves.
     * We must free the memory allocated here next time around. */
    makePSFontName((char *)family_fc, weight_fc, slant_fc,
        (char *)&state->name, sizeof(state->name));
    *fontname = (char *)&state->name;

    /* return the font path straight out of fontconfig */
    *path = (char*)file_fc;

    return 1;
#else
    return 0;
#endif
}

void gp_enumerate_fonts_free(void *enum_state)
{
#ifdef HAVE_FONTCONFIG
    unix_fontenum_t* state = (unix_fontenum_t *)enum_state;
    if (state != NULL) {
        if (state->font_list != NULL)
            FcFontSetDestroy(state->font_list);
        if (state->fc)
            FcConfigDestroy(state->fc);
        free(state);
    }
#endif
}

/* A function to decode the next codepoint of the supplied args from the
 * local windows codepage, or -1 for EOF.
 * (copied from gp_win32.c)
 */

#ifdef __MINGW32__
int
gp_local_arg_encoding_get_codepoint(gp_file *file, const char **astr)
{
    int len;
    int c;
    char arg[3];
    wchar_t unicode[2];
    char utf8[4];

    if (file) {
        c = gp_fgetc(file);
        if (c == EOF)
            return EOF;
    } else if (**astr) {
        c = *(*astr)++;
        if (c == 0)
            return EOF;
    } else {
        return EOF;
    }

    arg[0] = c;
    if (IsDBCSLeadByte(c)) {
        if (file) {
            c = gp_fgetc(file);
            if (c == EOF)
                return EOF;
        } else if (**astr) {
            c = *(*astr)++;
            if (c == 0)
                return EOF;
        }
        arg[1] = c;
        len = 2;
    } else {
        len = 1;
    }

    /* Convert the string (unterminated in, unterminated out) */
    len = MultiByteToWideChar(CP_ACP, 0, arg, len, unicode, 2);

    return unicode[0];
}
#endif