From: Cedric Roux <[email protected]> A ioctl interface and two ioctl commands added to /dev/vcsaN to get/put the current palette of the given tty.
Signed-off-by: Cedric Roux <[email protected]> --- This patch exists because there is no way to get the current installed palette of a given tty. The PIO_CMAP and GIO_CMAP in vt_ioctl.c:vt_ioctl play with the global default colormap. And /dev/vcsaN don't dump the palette through their read interface. And since a user may change colors of a given tty by escape sequences, one should be able to retrieve the palette through /dev/vcsaN, leading to this patch. Some points I am not fully confident with: - vt.c:set_colormap is now used in vc_screen.c so cannot be static anymore. The goal of this patch is to allow read access to the palette, I can remove the PIO_CMAP case and make set_colormap static again. This case is there because /dev/vcsaN is read/write so the access to the palette should also be read/write. (Or I can do it differently, no problem, just tell me how.) - the palette is returned as it is stored in the kernel, without taking into account color_table. So if a userland program gets an attribute for a given character, it won't match with the palette information. Say the user reads 0xXY through /dev/vcsa and takes Y as an index in the palette, it will return a bad color. One should do palette[color_table[Y]] to get the real color. Two "solutions" to this "problem" (it might be an non-issue): + export the palette by indexing with color_table: I don't like it. + let the userland program deal with that: the program may open a tty, send escape sequences to set the current color, write a character at a given position (through the tty, not /dev/vcs) and read back the attribute through /dev/vcsa this time. She will see what attribute corresponds to what color she sets by using escape sequences. If the color_table is non-mutable, all this is a non-issue. Userland programs just store the color_table and live with that. I've seen no code that modifies the color_table, so I bet it's non-mutable. (May it change in the future?) - lock_kernel() is called. Maybe it's not necessary? I'm not confident enough. You decide. diff -uprN -X linux-2.6.29.1/Documentation/dontdiff linux-2.6.29.1-vanilla/drivers/char/vc_screen.c linux-2.6.29.1/drivers/char/vc_screen.c --- linux-2.6.29.1-vanilla/drivers/char/vc_screen.c 2009-04-02 22:55:27.000000000 +0200 +++ linux-2.6.29.1/drivers/char/vc_screen.c 2009-04-14 10:16:33.000000000 +0200 @@ -19,6 +19,8 @@ * [email protected] - modified not to send characters to wrong console * - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...) * - making it shorter - scr_readw are macros which expand in PRETTY long code + * + * Colormap put/get for /dev/vcsaN, Cedric Roux <[email protected]>, March 2009. */ #include <linux/kernel.h> @@ -470,11 +472,67 @@ vcs_open(struct inode *inode, struct fil return ret; } +static long +vcs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + unsigned int currcons = iminor(file->f_path.dentry->d_inode); + struct vc_data *vc; + unsigned char pal[16*3]; + long ret = 0; + + /* access only defined for /dev/vcsaN, not /dev/vcsN */ + if (currcons < 128) + return -ENOTTY; + + lock_kernel(); + + acquire_console_sem(); + + currcons &= 127; + if (currcons == 0) + currcons = fg_console; + else + currcons--; + if (!vc_cons_allocated(currcons)) { + ret = -ENXIO; + goto unlock_out; + } + vc = vc_cons[currcons].d; + + switch (cmd) { + case PIO_CMAP: + if (copy_from_user(pal, (void __user *)arg, 16*3)) { + ret = -EFAULT; + goto unlock_out; + } + memcpy(vc->vc_palette, pal, 16*3); + set_palette(vc); + break; + case GIO_CMAP: + if (copy_to_user((void __user *)arg, vc->vc_palette, 16*3)) { + ret = -EFAULT; + goto unlock_out; + } + break; + default: + ret = -ENOIOCTLCMD; + break; + } + +unlock_out: + release_console_sem(); + + unlock_kernel(); + + return ret; +} + static const struct file_operations vcs_fops = { .llseek = vcs_lseek, .read = vcs_read, .write = vcs_write, .open = vcs_open, + .unlocked_ioctl = vcs_ioctl, }; static struct class *vc_class; diff -uprN -X linux-2.6.29.1/Documentation/dontdiff linux-2.6.29.1-vanilla/drivers/char/vt.c linux-2.6.29.1/drivers/char/vt.c --- linux-2.6.29.1-vanilla/drivers/char/vt.c 2009-04-02 22:55:27.000000000 +0200 +++ linux-2.6.29.1/drivers/char/vt.c 2009-04-14 10:17:20.000000000 +0200 @@ -156,7 +156,6 @@ static void set_cursor(struct vc_data *v static void hide_cursor(struct vc_data *vc); static void console_callback(struct work_struct *ignored); static void blank_screen_t(unsigned long dummy); -static void set_palette(struct vc_data *vc); static int printable; /* Is console ready for printing? */ int default_utf8 = true; @@ -3753,7 +3752,7 @@ void poke_blanked_console(void) * Palettes */ -static void set_palette(struct vc_data *vc) +void set_palette(struct vc_data *vc) { WARN_CONSOLE_UNLOCKED(); diff -uprN -X linux-2.6.29.1/Documentation/dontdiff linux-2.6.29.1-vanilla/include/linux/vt_kern.h linux-2.6.29.1/include/linux/vt_kern.h --- linux-2.6.29.1-vanilla/include/linux/vt_kern.h 2009-04-02 22:55:27.000000000 +0200 +++ linux-2.6.29.1/include/linux/vt_kern.h 2009-04-14 10:17:59.000000000 +0200 @@ -97,6 +97,7 @@ void reset_vc(struct vc_data *vc); extern int unbind_con_driver(const struct consw *csw, int first, int last, int deflt); int vty_init(const struct file_operations *console_fops); +void set_palette(struct vc_data *vc); /* * vc_screen.c shares this temporary buffer with the console write code so that -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
