remarkable-linux/include/linux/console.h
Antonino A. Daplas e400b6ec4e vt/vgacon: Check if screen resize request comes from userspace
Various console drivers are able to resize the screen via the con_resize()
hook.  This hook is also visible in userspace via the TIOCWINSZ, VT_RESIZE and
VT_RESIZEX ioctl's.  One particular utility, SVGATextMode, expects that
con_resize() of the VGA console will always return success even if the
resulting screen is not compatible with the hardware.  However, this
particular behavior of the VGA console, as reported in Kernel Bugzilla Bug
7513, can cause undefined behavior if the user starts with a console size
larger than 80x25.

To work around this problem, add an extra parameter to con_resize().  This
parameter is ignored by drivers except for vgacon.  If this parameter is
non-zero, then the resize request came from a VT_RESIZE or VT_RESIZEX ioctl
and vgacon will always return success.  If this parameter is zero, vgacon will
return -EINVAL if the requested size is not compatible with the hardware.  The
latter is the more correct behavior.

With this change, SVGATextMode should still work correctly while in-kernel and
stty resize calls can expect correct behavior from vgacon.

Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:20 -07:00

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C

/*
* linux/include/linux/console.h
*
* Copyright (C) 1993 Hamish Macdonald
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*
* Changed:
* 10-Mar-94: Arno Griffioen: Conversion for vt100 emulator port from PC LINUX
*/
#ifndef _LINUX_CONSOLE_H_
#define _LINUX_CONSOLE_H_ 1
#include <linux/types.h>
struct vc_data;
struct console_font_op;
struct console_font;
struct module;
struct tty_struct;
/*
* this is what the terminal answers to a ESC-Z or csi0c query.
*/
#define VT100ID "\033[?1;2c"
#define VT102ID "\033[?6c"
struct consw {
struct module *owner;
const char *(*con_startup)(void);
void (*con_init)(struct vc_data *, int);
void (*con_deinit)(struct vc_data *);
void (*con_clear)(struct vc_data *, int, int, int, int);
void (*con_putc)(struct vc_data *, int, int, int);
void (*con_putcs)(struct vc_data *, const unsigned short *, int, int, int);
void (*con_cursor)(struct vc_data *, int);
int (*con_scroll)(struct vc_data *, int, int, int, int);
void (*con_bmove)(struct vc_data *, int, int, int, int, int, int);
int (*con_switch)(struct vc_data *);
int (*con_blank)(struct vc_data *, int, int);
int (*con_font_set)(struct vc_data *, struct console_font *, unsigned);
int (*con_font_get)(struct vc_data *, struct console_font *);
int (*con_font_default)(struct vc_data *, struct console_font *, char *);
int (*con_font_copy)(struct vc_data *, int);
int (*con_resize)(struct vc_data *, unsigned int, unsigned int,
unsigned int);
int (*con_set_palette)(struct vc_data *, unsigned char *);
int (*con_scrolldelta)(struct vc_data *, int);
int (*con_set_origin)(struct vc_data *);
void (*con_save_screen)(struct vc_data *);
u8 (*con_build_attr)(struct vc_data *, u8, u8, u8, u8, u8, u8);
void (*con_invert_region)(struct vc_data *, u16 *, int);
u16 *(*con_screen_pos)(struct vc_data *, int);
unsigned long (*con_getxy)(struct vc_data *, unsigned long, int *, int *);
};
extern const struct consw *conswitchp;
extern const struct consw dummy_con; /* dummy console buffer */
extern const struct consw vga_con; /* VGA text console */
extern const struct consw newport_con; /* SGI Newport console */
extern const struct consw prom_con; /* SPARC PROM console */
int con_is_bound(const struct consw *csw);
int register_con_driver(const struct consw *csw, int first, int last);
int unregister_con_driver(const struct consw *csw);
int take_over_console(const struct consw *sw, int first, int last, int deflt);
void give_up_console(const struct consw *sw);
/* scroll */
#define SM_UP (1)
#define SM_DOWN (2)
/* cursor */
#define CM_DRAW (1)
#define CM_ERASE (2)
#define CM_MOVE (3)
/*
* The interface for a console, or any other device that wants to capture
* console messages (printer driver?)
*
* If a console driver is marked CON_BOOT then it will be auto-unregistered
* when the first real console is registered. This is for early-printk drivers.
*/
#define CON_PRINTBUFFER (1)
#define CON_CONSDEV (2) /* Last on the command line */
#define CON_ENABLED (4)
#define CON_BOOT (8)
#define CON_ANYTIME (16) /* Safe to call when cpu is offline */
struct console {
char name[16];
void (*write)(struct console *, const char *, unsigned);
int (*read)(struct console *, char *, unsigned);
struct tty_driver *(*device)(struct console *, int *);
void (*unblank)(void);
int (*setup)(struct console *, char *);
int (*early_setup)(void);
short flags;
short index;
int cflag;
void *data;
struct console *next;
};
extern int add_preferred_console(char *name, int idx, char *options);
extern int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options);
extern void register_console(struct console *);
extern int unregister_console(struct console *);
extern struct console *console_drivers;
extern void acquire_console_sem(void);
extern int try_acquire_console_sem(void);
extern void release_console_sem(void);
extern void console_conditional_schedule(void);
extern void console_unblank(void);
extern struct tty_driver *console_device(int *);
extern void console_stop(struct console *);
extern void console_start(struct console *);
extern int is_console_locked(void);
#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
/* Suspend and resume console messages over PM events */
extern void suspend_console(void);
extern void resume_console(void);
#else
static inline void suspend_console(void) {}
static inline void resume_console(void) {}
#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
int mda_console_init(void);
void prom_con_init(void);
void vcs_make_sysfs(struct tty_struct *tty);
void vcs_remove_sysfs(struct tty_struct *tty);
/* Some debug stub to catch some of the obvious races in the VT code */
#if 1
#define WARN_CONSOLE_UNLOCKED() WARN_ON(!is_console_locked() && !oops_in_progress)
#else
#define WARN_CONSOLE_UNLOCKED()
#endif
/* VESA Blanking Levels */
#define VESA_NO_BLANKING 0
#define VESA_VSYNC_SUSPEND 1
#define VESA_HSYNC_SUSPEND 2
#define VESA_POWERDOWN 3
#endif /* _LINUX_CONSOLE_H */