Commit 694d8a48 authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
Browse files

vt: separate unicode handling into vc_translate_unicode 



do_con_write is complicated enough. Extract unicode handling to a
separate function. For do_con_write, 249 LOCs lowered to 183 lines.

Use diff -w -b to see the difference is neligible -- mostly whitespace
and use of 'return's instead of 'continue's.

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-12-jslaby@suse.cz


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent da823b2d

drivers/tty/vt/vt.c

+81 −68
Original line number Diff line number Diff line
@@ -2572,6 +2572,85 @@ static inline int vc_translate_ascii(const struct vc_data *vc, int c) 
	return c;

}



/**

 * vc_translate_unicode -- Combine UTF-8 into Unicode in @vc_utf_char

 *

 * @vc_utf_char is the being-constructed unicode character.

 * @vc_utf_count is the number of continuation bytes still expected to arrive.

 * @vc_npar is the number of continuation bytes arrived so far.

 */

static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)

{

	static const u32 utf8_length_changes[] = {

		0x0000007f, 0x000007ff, 0x0000ffff,

		0x001fffff, 0x03ffffff, 0x7fffffff

	};



	if ((c & 0xc0) == 0x80) {

		/* Continuation byte received */

		if (vc->vc_utf_count) {

			vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);

			vc->vc_npar++;

			if (--vc->vc_utf_count) {

				/* Still need some bytes */

				return -1;

			}

			/* Got a whole character */

			c = vc->vc_utf_char;

			/* Reject overlong sequences */

			if (c <= utf8_length_changes[vc->vc_npar - 1] ||

					c > utf8_length_changes[vc->vc_npar])

				return 0xfffd;

		} else {

			/* Unexpected continuation byte */

			vc->vc_utf_count = 0;

			return 0xfffd;

		}

	} else {

		/* Single ASCII byte or first byte of a sequence received */

		if (vc->vc_utf_count) {

			/* Continuation byte expected */

			*rescan = true;

			vc->vc_utf_count = 0;

			return 0xfffd;

		} else if (c > 0x7f) {

			/* First byte of a multibyte sequence received */

			vc->vc_npar = 0;

			if ((c & 0xe0) == 0xc0) {

				vc->vc_utf_count = 1;

				vc->vc_utf_char = (c & 0x1f);

			} else if ((c & 0xf0) == 0xe0) {

				vc->vc_utf_count = 2;

				vc->vc_utf_char = (c & 0x0f);

			} else if ((c & 0xf8) == 0xf0) {

				vc->vc_utf_count = 3;

				vc->vc_utf_char = (c & 0x07);

			} else if ((c & 0xfc) == 0xf8) {

				vc->vc_utf_count = 4;

				vc->vc_utf_char = (c & 0x03);

			} else if ((c & 0xfe) == 0xfc) {

				vc->vc_utf_count = 5;

				vc->vc_utf_char = (c & 0x01);

			} else {

				/* 254 and 255 are invalid */

				return 0xfffd;

			}

			if (vc->vc_utf_count) {

				/* Still need some bytes */

				return -1;

			}

		}

		/* Nothing to do if an ASCII byte was received */

	}

	/* End of UTF-8 decoding. */

	/* c is the received character, or U+FFFD for invalid sequences. */

	/* Replace invalid Unicode code points with U+FFFD too */

	if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)

		return 0xfffd;



	return c;

}



/* acquires console_lock */

static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int count)

{
@@ -2628,76 +2707,10 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co 
		if (vc->vc_state != ESnormal) {

			tc = c;

		} else if (vc->vc_utf && !vc->vc_disp_ctrl) {

		    /* Combine UTF-8 into Unicode in vc_utf_char.

		     * vc_utf_count is the number of continuation bytes still

		     * expected to arrive.

		     * vc_npar is the number of continuation bytes arrived so

		     * far

		     */

rescan_last_byte:

		    if ((c & 0xc0) == 0x80) {

			/* Continuation byte received */

			static const uint32_t utf8_length_changes[] = { 0x0000007f, 0x000007ff, 0x0000ffff, 0x001fffff, 0x03ffffff, 0x7fffffff };

			if (vc->vc_utf_count) {

			    vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);

			    vc->vc_npar++;

			    if (--vc->vc_utf_count) {

				/* Still need some bytes */

				continue;

			    }

			    /* Got a whole character */

			    c = vc->vc_utf_char;

			    /* Reject overlong sequences */

			    if (c <= utf8_length_changes[vc->vc_npar - 1] ||

					c > utf8_length_changes[vc->vc_npar])

				c = 0xfffd;

			} else {

			    /* Unexpected continuation byte */

			    vc->vc_utf_count = 0;

			    c = 0xfffd;

			}

		    } else {

			/* Single ASCII byte or first byte of a sequence received */

			if (vc->vc_utf_count) {

			    /* Continuation byte expected */

			    rescan = true;

			    vc->vc_utf_count = 0;

			    c = 0xfffd;

			} else if (c > 0x7f) {

			    /* First byte of a multibyte sequence received */

			    vc->vc_npar = 0;

			    if ((c & 0xe0) == 0xc0) {

				vc->vc_utf_count = 1;

				vc->vc_utf_char = (c & 0x1f);

			    } else if ((c & 0xf0) == 0xe0) {

				vc->vc_utf_count = 2;

				vc->vc_utf_char = (c & 0x0f);

			    } else if ((c & 0xf8) == 0xf0) {

				vc->vc_utf_count = 3;

				vc->vc_utf_char = (c & 0x07);

			    } else if ((c & 0xfc) == 0xf8) {

				vc->vc_utf_count = 4;

				vc->vc_utf_char = (c & 0x03);

			    } else if ((c & 0xfe) == 0xfc) {

				vc->vc_utf_count = 5;

				vc->vc_utf_char = (c & 0x01);

			    } else {

				/* 254 and 255 are invalid */

				c = 0xfffd;

			    }

			    if (vc->vc_utf_count) {

				/* Still need some bytes */

			tc = c = vc_translate_unicode(vc, c, &rescan);

			if (tc == -1)

				continue;

			    }

			}

			/* Nothing to do if an ASCII byte was received */

		    }

		    /* End of UTF-8 decoding. */

		    /* c is the received character, or U+FFFD for invalid sequences. */

		    /* Replace invalid Unicode code points with U+FFFD too */

		    if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)

			c = 0xfffd;

		    tc = c;

		} else {	/* no utf or alternate charset mode */

			tc = vc_translate_ascii(vc, c);

		}

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