patch-2.1.16 linux/drivers/char/vc_screen.c

• Lines: 277
• Date: Fri Dec 13 16:04:14 1996
• Orig file: v2.1.15/linux/drivers/char/vc_screen.c
• Orig date: Tue Oct 29 19:58:10 1996

diff -u --recursive --new-file v2.1.15/linux/drivers/char/vc_screen.c linux/drivers/char/vc_screen.c
@@ -14,24 +14,53 @@
  * administrator can control access using file system permissions.
  *
  * aeb@cwi.nl - efter Friedas begravelse - 950211
+ *
+ * machek@k332.feld.cvut.cz - modified not to send characters to wrong console
+ *	 - fixed some fatal of-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
+ *	 - making it working with multiple monitor patches
+ *	 - making it shorter - scr_readw are macros which expand in PRETTY long code
  */
 
+#include <linux/config.h>
+
 #include <linux/kernel.h>
 #include <linux/major.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
 #include <linux/sched.h>
+#include <linux/interrupt.h>
 #include <linux/mm.h>
 #include <asm/uaccess.h>
 #include "vt_kern.h"
 #include "selection.h"
 
+#undef attr
+#undef org
+#undef addr
 #define HEADER_SIZE	4
 
-static inline int
+static unsigned short
+func_scr_readw(unsigned short *org)
+{
+return scr_readw( org );
+}
+
+static void
+func_scr_writew(unsigned short val, unsigned short *org)
+{
+scr_writew( val, org );
+}
+
+static int
 vcs_size(struct inode *inode)
 {
-	int size = video_num_lines * video_num_columns;
+	int size;
+#ifdef CONFIG_MULTIMON
+   	int currcons = MINOR(inode->i_rdev) & 127;
+	/* Multimon patch	*/
+	if (!vc_cons[currcons].d) return 0;
+#endif
+   	size= video_num_lines * video_num_columns;
 	if (MINOR(inode->i_rdev) & 128)
 		size = 2*size + HEADER_SIZE;
 	return size;
@@ -40,7 +69,8 @@
 static long long
 vcs_lseek(struct inode *inode, struct file *file, long long offset, int orig)
 {
-	int size = vcs_size(inode);
+	int size;
+	size = vcs_size(inode);
 
 	switch (orig) {
 		case 0:
@@ -56,145 +86,154 @@
 			return -EINVAL;
 	}
 	if (file->f_pos < 0 || file->f_pos > size)
-		return -EINVAL;
+		{ file->f_pos = 0; return -EINVAL; }
 	return file->f_pos;
 }
 
+#define RETURN( x ) { enable_bh( CONSOLE_BH ); return x; }
 static long
 vcs_read(struct inode *inode, struct file *file, char *buf, unsigned long count)
 {
-	unsigned long p = file->f_pos;
-	unsigned int cons = MINOR(inode->i_rdev);
+	int p = file->f_pos;
+	unsigned int currcons = MINOR(inode->i_rdev);
 	int viewed, attr, size, read;
 	char *buf0;
 	unsigned short *org;
 
-	attr = (cons & 128);
-	cons = (cons & 127);
-	if (cons == 0) {
-		cons = fg_console;
+	attr = (currcons & 128);
+	currcons = (currcons & 127);
+	disable_bh( CONSOLE_BH );
+	if (currcons == 0) {
+		currcons = fg_console;
 		viewed = 1;
 	} else {
-		cons--;
+		currcons--;
 		viewed = 0;
 	}
-	if (!vc_cons_allocated(cons))
-		return -ENXIO;
+	if (!vc_cons_allocated(currcons))
+		RETURN( -ENXIO );
 
 	size = vcs_size(inode);
-	if (p > size)
-		return -EINVAL;
+	if (p < 0 || p > size)
+		RETURN( -EINVAL );
 	if (count > size - p)
 		count = size - p;
 
 	buf0 = buf;
 	if (!attr) {
-		org = screen_pos(cons, p, viewed);
+		org = screen_pos(currcons, p, viewed);
 		while (count-- > 0)
-			put_user(scr_readw(org++) & 0xff, buf++);
+			put_user(func_scr_readw(org++) & 0xff, buf++);
 	} else {
 		if (p < HEADER_SIZE) {
 			char header[HEADER_SIZE];
 			header[0] = (char) video_num_lines;
 			header[1] = (char) video_num_columns;
-			getconsxy(cons, header+2);
-			while (p < HEADER_SIZE && count-- > 0)
-			    put_user(header[p++], buf++);
-		}
-		p -= HEADER_SIZE;
-		org = screen_pos(cons, p/2, viewed);
-		if ((p & 1) && count-- > 0)
-			put_user(scr_readw(org++) >> 8, buf++);
+			getconsxy(currcons, header+2);
+			while (p < HEADER_SIZE && count > 0)
+			    { count--; put_user(header[p++], buf++); }
+		}
+		if (count > 0) {
+		    p -= HEADER_SIZE;
+		    org = screen_pos(currcons, p/2, viewed);
+		    if ((p & 1) && count > 0)
+			    { count--; put_user(func_scr_readw(org++) >> 8, buf++); }
+		}
 		while (count > 1) {
-			put_user(scr_readw(org++), (unsigned short *) buf);
+			put_user(func_scr_readw(org++), (unsigned short *) buf);
 			buf += 2;
 			count -= 2;
 		}
 		if (count > 0)
-			put_user(scr_readw(org) & 0xff, buf++);
+			put_user(func_scr_readw(org) & 0xff, buf++);
 	}
 	read = buf - buf0;
 	file->f_pos += read;
-	return read;
+	RETURN( read );
 }
 
 static long
 vcs_write(struct inode *inode, struct file *file, const char *buf, unsigned long count)
 {
-	unsigned long p = file->f_pos;
-	unsigned int cons = MINOR(inode->i_rdev);
+	int p = file->f_pos;
+	unsigned int currcons = MINOR(inode->i_rdev);
 	int viewed, attr, size, written;
 	const char *buf0;
 	unsigned short *org;
 
-	attr = (cons & 128);
-	cons = (cons & 127);
-	if (cons == 0) {
-		cons = fg_console;
+	attr = (currcons & 128);
+	currcons = (currcons & 127);
+	disable_bh( CONSOLE_BH );
+	if (currcons == 0) {
+		currcons = fg_console;
 		viewed = 1;
 	} else {
-		cons--;
+		currcons--;
 		viewed = 0;
 	}
-	if (!vc_cons_allocated(cons))
-		return -ENXIO;
+	if (!vc_cons_allocated(currcons))
+		RETURN( -ENXIO );
 
 	size = vcs_size(inode);
-	if (p > size)
-		return -EINVAL;
+	if (p < 0 || p > size)
+		RETURN( -EINVAL );
 	if (count > size - p)
 		count = size - p;
 
 	buf0 = buf;
 	if (!attr) {
-		org = screen_pos(cons, p, viewed);
-		while (count-- > 0) {
+		org = screen_pos(currcons, p, viewed);
+		while (count > 0) {
 			unsigned char c;
+			count--;
 			get_user(c, (const unsigned char*)buf++);
-			scr_writew((scr_readw(org) & 0xff00) | c, org);
+			func_scr_writew((func_scr_readw(org) & 0xff00) | c, org);
 			org++;
 		}
 	} else {
 		if (p < HEADER_SIZE) {
 			char header[HEADER_SIZE];
-			getconsxy(cons, header+2);
-			while (p < HEADER_SIZE && count-- > 0)
-				get_user(header[p++], buf++);
+			getconsxy(currcons, header+2);
+			while (p < HEADER_SIZE && count > 0)
+				{ count--; get_user(header[p++], buf++); }
 			if (!viewed)
-				putconsxy(cons, header+2);
+				putconsxy(currcons, header+2);
 		}
-		p -= HEADER_SIZE;
-		org = screen_pos(cons, p/2, viewed);
-		if ((p & 1) && count-- > 0) {
-			char c;
-			get_user(c,buf++);
-			scr_writew((c << 8) |
-				   (scr_readw(org) & 0xff), org);
-			org++;
+		if (count > 0) {
+		    p -= HEADER_SIZE;
+			org = screen_pos(currcons, p/2, viewed);
+			if ((p & 1) && count > 0) {
+			    char c;
+				count--;
+				get_user(c,buf++);
+				func_scr_writew((c << 8) |
+				     (func_scr_readw(org) & 0xff), org);
+				org++;
+			}
 		}
 		while (count > 1) {
 			unsigned short w;
 			get_user(w, (const unsigned short *) buf);
-			scr_writew(w, org++);
+			func_scr_writew(w, org++);
 			buf += 2;
 			count -= 2;
 		}
 		if (count > 0) {
 			unsigned char c;
 			get_user(c, (const unsigned char*)buf++);
-			scr_writew((scr_readw(org) & 0xff00) | c, org);
+			func_scr_writew((func_scr_readw(org) & 0xff00) | c, org);
 		}
 	}
 	written = buf - buf0;
 	file->f_pos += written;
-	return written;
+	RETURN( written );
 }
 
 static int
 vcs_open(struct inode *inode, struct file *filp)
 {
-	unsigned int cons = (MINOR(inode->i_rdev) & 127);
-	if(cons && !vc_cons_allocated(cons-1))
+	unsigned int currcons = (MINOR(inode->i_rdev) & 127);
+	if(currcons && !vc_cons_allocated(currcons-1))
 		return -ENXIO;
 	return 0;
 }