Bug#456437: manpages: vcsa(4) documentation fix and update

[Samuel Thibault]

Package: manpages
Version: 2.67-1
Severity: normal
Tags: patch

Hello,

Here is a documentation fix for vcsa(4): attribute/text characters are
in the host endianness.  Also, document the VT_GETHIFONTMASK ioctl.

Samuel

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (500, 'stable'), (1, 
'experimental')
Architecture: i386 (i686)

Kernel: Linux 2.6.23
Locale: [EMAIL PROTECTED], [EMAIL PROTECTED] (charmap=ISO-8859-15)
Shell: /bin/sh linked to /bin/bash

-- no debconf information

-- 
Samuel
* D a decide de peter un cable dans son rapport de pfp
<c> et il a bien raison ;-)
<c> tu vas dire quoi ?
<D> j'ai mis les paroles de "le coq est mort" en en-tete
 -+- #ens-mim et la peufeupeu -+-

--- vcsa.4.orig 2007-12-15 17:31:48.000000000 +0000
+++ vcsa.4      2007-12-15 18:05:21.000000000 +0000
@@ -36,9 +36,13 @@
 terminals, they have major number 7 and minor number 1 to 63, usually
 mode 0644 and owner root.tty.
 \fI/dev/vcsa[0\-63]\fP are the same, but
-including attributes, and prefixed with four bytes giving the screen
+using unsigned shorts (in host byte endianity) that include attributes, and
+prefixed with four bytes giving the screen
 dimensions and cursor position: \fIlines\fP, \fIcolumns\fP, \fIx\fP, \fIy\fP.
-(\fIx\fP = \fIy\fP = 0 at the top left corner of the screen.)
+(\fIx\fP = \fIy\fP = 0 at the top left corner of the screen.)  When a 512
+character font is loaded, the 9th bit position can be fetched thanks to calling
+the \fIVT_GETHIFONTMASK\fP ioctl on \fI/dev/tty[1\-63]\fP (available in Linux
+kernels 2.6.18 and above).
 .PP
 These replace the screendump
 .IR ioctl s
@@ -87,15 +91,30 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/vt.h>
 
 int
 main(void)
 {
     int fd;
     char *device = "/dev/vcsa2";
+    char *console = "/dev/tty2";
     struct {unsigned char lines, cols, x, y;} scrn;
-    char ch, attrib;
+    unsigned short s;
+    unsigned short mask;
+    unsigned char ch, attrib;
 
+    fd = open(console, O_RDWR);
+    if (fd < 0) {
+        perror(console);
+        exit(EXIT_FAILURE);
+    }
+    if (ioctl(fd, VT_GETHIFONTMASK, &mask) < 0) {
+        perror("VT_GETHIFONTMASK");
+        exit(EXIT_FAILURE);
+    }
+    (void) close(fd);
     fd = open(device, O_RDWR);
     if (fd < 0) {
         perror(device);
@@ -103,8 +122,11 @@
     }
     (void) read(fd, &scrn, 4);
     (void) lseek(fd, 4 + 2*(scrn.y*scrn.cols + scrn.x), 0);
-    (void) read(fd, &ch, 1);
-    (void) read(fd, &attrib, 1);
+    (void) read(fd, &s, 2);
+    ch = s & 0xff;
+    if (attrib & mask)
+        ch |= 0x100;
+    attrib = ((s & ~mask) >> 8);
     printf("ch='%c' attrib=0x%02x\\n", ch, attrib);
     attrib ^= 0x10;
     (void) lseek(fd, \-1, 1);