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/*
 * loadfont.c - Eugene Crosser & Andries Brouwer
 *
 * Version 0.96bb
 *
 * Loads the console font, and possibly the corresponding screen map(s).
 * (Adapted for busybox by Matej Vela.)
 */
#include "internal.h"
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <memory.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/kd.h>
#include <endian.h>

#define PSF_MAGIC1	0x36
#define PSF_MAGIC2	0x04

#define PSF_MODE512    0x01
#define PSF_MODEHASTAB 0x02
#define PSF_MAXMODE    0x03
#define PSF_SEPARATOR  0xFFFF

static const char loadfont_usage[] = "loadfont\n"
"\n"
"\tLoad a console font from standard input.\n"
"\n";

struct psf_header
{
  unsigned char magic1, magic2;	/* Magic number */
  unsigned char mode;		/* PSF font mode */
  unsigned char charsize;	/* Character size */
};

#define PSF_MAGIC_OK(x)	((x).magic1 == PSF_MAGIC1 && (x).magic2 == PSF_MAGIC2)

static void loadnewfont(int fd);

extern int
loadfont_main(int argc, char **argv)
{
	int fd;

	fd = open("/dev/tty0", O_RDWR);
	if (fd < 0) {
	    fprintf(stderr, "Error opening /dev/tty0: %s\n", strerror(errno));
	    return 1;
	}
	loadnewfont(fd);

	return 0;
}

static void
do_loadfont(int fd, char *inbuf, int unit, int fontsize) {
	char buf[16384];
	int i;

	memset(buf,0,sizeof(buf));

	if (unit < 1 || unit > 32) {
	    fprintf(stderr, "Bad character size %d\n", unit);
	    exit(1);
	}

	for (i = 0; i < fontsize; i++)
	    memcpy(buf+(32*i), inbuf+(unit*i), unit);

#if defined( PIO_FONTX ) && !defined( __sparc__ )
	{
	    struct consolefontdesc cfd;

	    cfd.charcount = fontsize;
	    cfd.charheight = unit;
	    cfd.chardata = buf;

	    if (ioctl(fd, PIO_FONTX, &cfd) == 0)
	      return;		/* success */
	    perror("PIO_FONTX ioctl error (trying PIO_FONT)");
	}
#endif
	if (ioctl(fd, PIO_FONT, buf)) {
	    perror("PIO_FONT ioctl error");
	    exit(1);
	}
}

static void
do_loadtable(int fd, unsigned char *inbuf, int tailsz, int fontsize) {
	struct unimapinit advice;
	struct unimapdesc ud;
	struct unipair *up;
	int ct = 0, maxct;
	int glyph;
	u_short unicode;

	maxct = tailsz;		/* more than enough */
	up = (struct unipair *) malloc(maxct * sizeof(struct unipair));
	if (!up) {
	    fprintf(stderr, "Out of memory?\n");
	    exit(1);
	}
	for (glyph = 0; glyph < fontsize; glyph++) {
	    while (tailsz >= 2) {
		unicode = (((u_short) inbuf[1]) << 8) + inbuf[0];
		tailsz -= 2;
		inbuf += 2;
		if (unicode == PSF_SEPARATOR)
		    break;
		up[ct].unicode = unicode;
		up[ct].fontpos = glyph;
		ct++;
	    }
	}

	/* Note: after PIO_UNIMAPCLR and before PIO_UNIMAP
	   this printf did not work on many kernels */

	advice.advised_hashsize = 0;
	advice.advised_hashstep = 0;
	advice.advised_hashlevel = 0;
	if(ioctl(fd, PIO_UNIMAPCLR, &advice)) {
#ifdef ENOIOCTLCMD
	    if (errno == ENOIOCTLCMD) {
		fprintf(stderr, "It seems this kernel is older than 1.1.92\n");
		fprintf(stderr, "No Unicode mapping table loaded.\n");
	    } else
#endif
	      perror("PIO_UNIMAPCLR");
	    exit(1);
	}
	ud.entry_ct = ct;
	ud.entries = up;
	if(ioctl(fd, PIO_UNIMAP, &ud)) {
#if 0
	    if (errno == ENOMEM) {
		/* change advice parameters */
	    }
#endif
	    perror("PIO_UNIMAP");
	    exit(1);
	}
}

static void
loadnewfont(int fd) {
	int unit;
	char inbuf[32768];	/* primitive */
	int inputlth, offset;

	/*
	 * We used to look at the length of the input file
	 * with stat(); now that we accept compressed files,
	 * just read the entire file.
	 */
	inputlth = fread(inbuf, 1, sizeof(inbuf), stdin);
	if (ferror(stdin)) {
		perror("Error reading input font");
		exit(1);
	}
	/* use malloc/realloc in case of giant files;
	   maybe these do not occur: 16kB for the font,
	   and 16kB for the map leaves 32 unicode values
	   for each font position */
	if (!feof(stdin)) {
		perror("Font too large");
		exit(1);
	}

	/* test for psf first */
	{
	    struct psf_header psfhdr;
	    int fontsize;
	    int hastable;
	    int head0, head;

	    if (inputlth < sizeof(struct psf_header))
		goto no_psf;

	    psfhdr = * (struct psf_header *) &inbuf[0];

	    if (!PSF_MAGIC_OK(psfhdr))
		goto no_psf;

	    if (psfhdr.mode > PSF_MAXMODE) {
		fprintf(stderr, "Unsupported psf file mode\n");
		exit(1);
	    }
	    fontsize = ((psfhdr.mode & PSF_MODE512) ? 512 : 256);
#if !defined( PIO_FONTX ) || defined( __sparc__ )
	    if (fontsize != 256) {
		fprintf(stderr, "Only fontsize 256 supported\n");
		exit(1);
	    }
#endif
	    hastable = (psfhdr.mode & PSF_MODEHASTAB);
	    unit = psfhdr.charsize;
	    head0 = sizeof(struct psf_header);
	    head = head0 + fontsize*unit;
	    if (head > inputlth || (!hastable && head != inputlth)) {
		fprintf(stderr, "Input file: bad length\n");
		exit(1);
	    }
	    do_loadfont(fd, inbuf + head0, unit, fontsize);
	    if (hastable)
	      do_loadtable(fd, inbuf + head, inputlth-head, fontsize);
	    return;
	}
      no_psf:

	/* file with three code pages? */
	if (inputlth == 9780) {
	    offset = 40;
	    unit = 16;
	} else {
	    /* bare font */
	    if (inputlth & 0377) {
		fprintf(stderr, "Bad input file size\n");
		exit(1);
	    }
	    offset = 0;
	    unit = inputlth/256;
	}
	do_loadfont(fd, inbuf+offset, unit, 256);
}