// SPDX-License-Identifier: GPL-2.0 /* * Provide access to virtual console memory. * /dev/vcs: the screen as it is being viewed right now (possibly scrolled) * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63) * [minor: N] * * /dev/vcsaN: idem, but including attributes, and prefixed with * the 4 bytes lines,columns,x,y (as screendump used to give). * Attribute/character pair is in native endianity. * [minor: N+128] * * /dev/vcsuN: similar to /dev/vcsaN but using 4-byte unicode values * instead of 1-byte screen glyph values. * [minor: N+64] * * /dev/vcsuaN: same idea as /dev/vcsaN for unicode (not yet implemented). * * This replaces screendump and part of selection, so that the system * administrator can control access using file system permissions. * * [email protected] - efter Friedas begravelse - 950211 * * [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 */ #include <linux/kernel.h> #include <linux/major.h> #include <linux/errno.h> #include <linux/export.h> #include <linux/tty.h> #include <linux/interrupt.h> #include <linux/mm.h> #include <linux/init.h> #include <linux/vt_kern.h> #include <linux/selection.h> #include <linux/kbd_kern.h> #include <linux/console.h> #include <linux/device.h> #include <linux/sched.h> #include <linux/fs.h> #include <linux/poll.h> #include <linux/signal.h> #include <linux/slab.h> #include <linux/notifier.h> #include <linux/uaccess.h> #include <asm/byteorder.h> #include <asm/unaligned.h> #define HEADER_SIZE … #define CON_BUF_SIZE … /* * Our minor space: * * 0 ... 63 glyph mode without attributes * 64 ... 127 unicode mode without attributes * 128 ... 191 glyph mode with attributes * 192 ... 255 unused (reserved for unicode with attributes) * * This relies on MAX_NR_CONSOLES being <= 63, meaning 63 actual consoles * with minors 0, 64, 128 and 192 being proxies for the foreground console. */ #if MAX_NR_CONSOLES > 63 #warning "/dev/vcs* devices may not accommodate more than 63 consoles" #endif #define console(inode) … #define use_unicode(inode) … #define use_attributes(inode) … struct vcs_poll_data { … }; static int vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param) { … } static void vcs_poll_data_free(struct vcs_poll_data *poll) { … } static struct vcs_poll_data * vcs_poll_data_get(struct file *file) { … } /** * vcs_vc - return VC for @inode * @inode: inode for which to return a VC * @viewed: returns whether this console is currently foreground (viewed) * * Must be called with console_lock. */ static struct vc_data *vcs_vc(struct inode *inode, bool *viewed) { … } /** * vcs_size - return size for a VC in @vc * @vc: which VC * @attr: does it use attributes? * @unicode: is it unicode? * * Must be called with console_lock. */ static int vcs_size(const struct vc_data *vc, bool attr, bool unicode) { … } static loff_t vcs_lseek(struct file *file, loff_t offset, int orig) { … } static int vcs_read_buf_uni(struct vc_data *vc, char *con_buf, unsigned int pos, unsigned int count, bool viewed) { … } static void vcs_read_buf_noattr(const struct vc_data *vc, char *con_buf, unsigned int pos, unsigned int count, bool viewed) { … } static unsigned int vcs_read_buf(const struct vc_data *vc, char *con_buf, unsigned int pos, unsigned int count, bool viewed, unsigned int *skip) { … } static ssize_t vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { … } static u16 *vcs_write_buf_noattr(struct vc_data *vc, const char *con_buf, unsigned int pos, unsigned int count, bool viewed, u16 **org0) { … } /* * Compilers (gcc 10) are unable to optimize the swap in cpu_to_le16. So do it * the poor man way. */ static inline u16 vc_compile_le16(u8 hi, u8 lo) { … } static u16 *vcs_write_buf(struct vc_data *vc, const char *con_buf, unsigned int pos, unsigned int count, bool viewed, u16 **org0) { … } static ssize_t vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { … } static __poll_t vcs_poll(struct file *file, poll_table *wait) { … } static int vcs_fasync(int fd, struct file *file, int on) { … } static int vcs_open(struct inode *inode, struct file *filp) { … } static int vcs_release(struct inode *inode, struct file *file) { … } static const struct file_operations vcs_fops = …; static const struct class vc_class = …; void vcs_make_sysfs(int index) { … } void vcs_remove_sysfs(int index) { … } int __init vcs_init(void) { … }
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