| /* |
| * linux/drivers/char/vc_screen.c |
| * |
| * Provide access to virtual console memory. |
| * /dev/vcs0: 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] |
| * |
| * This replaces screendump and part of selection, so that the system |
| * 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 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/config.h> |
| #include <linux/kernel.h> |
| #include <linux/major.h> |
| #include <linux/errno.h> |
| #include <linux/tty.h> |
| #include <linux/devfs_fs_kernel.h> |
| #include <linux/sched.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/smp_lock.h> |
| #include <linux/device.h> |
| #include <asm/uaccess.h> |
| #include <asm/byteorder.h> |
| #include <asm/unaligned.h> |
| |
| #undef attr |
| #undef org |
| #undef addr |
| #define HEADER_SIZE 4 |
| |
| static int |
| vcs_size(struct inode *inode) |
| { |
| int size; |
| int minor = iminor(inode); |
| int currcons = minor & 127; |
| struct vc_data *vc; |
| |
| if (currcons == 0) |
| currcons = fg_console; |
| else |
| currcons--; |
| if (!vc_cons_allocated(currcons)) |
| return -ENXIO; |
| vc = vc_cons[currcons].d; |
| |
| size = vc->vc_rows * vc->vc_cols; |
| |
| if (minor & 128) |
| size = 2*size + HEADER_SIZE; |
| return size; |
| } |
| |
| static loff_t vcs_lseek(struct file *file, loff_t offset, int orig) |
| { |
| int size; |
| |
| down(&con_buf_sem); |
| size = vcs_size(file->f_dentry->d_inode); |
| switch (orig) { |
| default: |
| up(&con_buf_sem); |
| return -EINVAL; |
| case 2: |
| offset += size; |
| break; |
| case 1: |
| offset += file->f_pos; |
| case 0: |
| break; |
| } |
| if (offset < 0 || offset > size) { |
| up(&con_buf_sem); |
| return -EINVAL; |
| } |
| file->f_pos = offset; |
| up(&con_buf_sem); |
| return file->f_pos; |
| } |
| |
| |
| static ssize_t |
| vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct inode *inode = file->f_dentry->d_inode; |
| unsigned int currcons = iminor(inode); |
| struct vc_data *vc; |
| long pos; |
| long viewed, attr, read; |
| int col, maxcol; |
| unsigned short *org = NULL; |
| ssize_t ret; |
| |
| down(&con_buf_sem); |
| |
| pos = *ppos; |
| |
| /* Select the proper current console and verify |
| * sanity of the situation under the console lock. |
| */ |
| acquire_console_sem(); |
| |
| attr = (currcons & 128); |
| currcons = (currcons & 127); |
| if (currcons == 0) { |
| currcons = fg_console; |
| viewed = 1; |
| } else { |
| currcons--; |
| viewed = 0; |
| } |
| ret = -ENXIO; |
| if (!vc_cons_allocated(currcons)) |
| goto unlock_out; |
| vc = vc_cons[currcons].d; |
| |
| ret = -EINVAL; |
| if (pos < 0) |
| goto unlock_out; |
| read = 0; |
| ret = 0; |
| while (count) { |
| char *con_buf0, *con_buf_start; |
| long this_round, size; |
| ssize_t orig_count; |
| long p = pos; |
| |
| /* Check whether we are above size each round, |
| * as copy_to_user at the end of this loop |
| * could sleep. |
| */ |
| size = vcs_size(inode); |
| if (pos >= size) |
| break; |
| if (count > size - pos) |
| count = size - pos; |
| |
| this_round = count; |
| if (this_round > CON_BUF_SIZE) |
| this_round = CON_BUF_SIZE; |
| |
| /* Perform the whole read into the local con_buf. |
| * Then we can drop the console spinlock and safely |
| * attempt to move it to userspace. |
| */ |
| |
| con_buf_start = con_buf0 = con_buf; |
| orig_count = this_round; |
| maxcol = vc->vc_cols; |
| if (!attr) { |
| org = screen_pos(vc, p, viewed); |
| col = p % maxcol; |
| p += maxcol - col; |
| while (this_round-- > 0) { |
| *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff); |
| if (++col == maxcol) { |
| org = screen_pos(vc, p, viewed); |
| col = 0; |
| p += maxcol; |
| } |
| } |
| } else { |
| if (p < HEADER_SIZE) { |
| size_t tmp_count; |
| |
| con_buf0[0] = (char)vc->vc_rows; |
| con_buf0[1] = (char)vc->vc_cols; |
| getconsxy(vc, con_buf0 + 2); |
| |
| con_buf_start += p; |
| this_round += p; |
| if (this_round > CON_BUF_SIZE) { |
| this_round = CON_BUF_SIZE; |
| orig_count = this_round - p; |
| } |
| |
| tmp_count = HEADER_SIZE; |
| if (tmp_count > this_round) |
| tmp_count = this_round; |
| |
| /* Advance state pointers and move on. */ |
| this_round -= tmp_count; |
| p = HEADER_SIZE; |
| con_buf0 = con_buf + HEADER_SIZE; |
| /* If this_round >= 0, then p is even... */ |
| } else if (p & 1) { |
| /* Skip first byte for output if start address is odd |
| * Update region sizes up/down depending on free |
| * space in buffer. |
| */ |
| con_buf_start++; |
| if (this_round < CON_BUF_SIZE) |
| this_round++; |
| else |
| orig_count--; |
| } |
| if (this_round > 0) { |
| unsigned short *tmp_buf = (unsigned short *)con_buf0; |
| |
| p -= HEADER_SIZE; |
| p /= 2; |
| col = p % maxcol; |
| |
| org = screen_pos(vc, p, viewed); |
| p += maxcol - col; |
| |
| /* Buffer has even length, so we can always copy |
| * character + attribute. We do not copy last byte |
| * to userspace if this_round is odd. |
| */ |
| this_round = (this_round + 1) >> 1; |
| |
| while (this_round) { |
| *tmp_buf++ = vcs_scr_readw(vc, org++); |
| this_round --; |
| if (++col == maxcol) { |
| org = screen_pos(vc, p, viewed); |
| col = 0; |
| p += maxcol; |
| } |
| } |
| } |
| } |
| |
| /* Finally, release the console semaphore while we push |
| * all the data to userspace from our temporary buffer. |
| * |
| * AKPM: Even though it's a semaphore, we should drop it because |
| * the pagefault handling code may want to call printk(). |
| */ |
| |
| release_console_sem(); |
| ret = copy_to_user(buf, con_buf_start, orig_count); |
| acquire_console_sem(); |
| |
| if (ret) { |
| read += (orig_count - ret); |
| ret = -EFAULT; |
| break; |
| } |
| buf += orig_count; |
| pos += orig_count; |
| read += orig_count; |
| count -= orig_count; |
| } |
| *ppos += read; |
| if (read) |
| ret = read; |
| unlock_out: |
| release_console_sem(); |
| up(&con_buf_sem); |
| return ret; |
| } |
| |
| static ssize_t |
| vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct inode *inode = file->f_dentry->d_inode; |
| unsigned int currcons = iminor(inode); |
| struct vc_data *vc; |
| long pos; |
| long viewed, attr, size, written; |
| char *con_buf0; |
| int col, maxcol; |
| u16 *org0 = NULL, *org = NULL; |
| size_t ret; |
| |
| down(&con_buf_sem); |
| |
| pos = *ppos; |
| |
| /* Select the proper current console and verify |
| * sanity of the situation under the console lock. |
| */ |
| acquire_console_sem(); |
| |
| attr = (currcons & 128); |
| currcons = (currcons & 127); |
| |
| if (currcons == 0) { |
| currcons = fg_console; |
| viewed = 1; |
| } else { |
| currcons--; |
| viewed = 0; |
| } |
| ret = -ENXIO; |
| if (!vc_cons_allocated(currcons)) |
| goto unlock_out; |
| vc = vc_cons[currcons].d; |
| |
| size = vcs_size(inode); |
| ret = -EINVAL; |
| if (pos < 0 || pos > size) |
| goto unlock_out; |
| if (count > size - pos) |
| count = size - pos; |
| written = 0; |
| while (count) { |
| long this_round = count; |
| size_t orig_count; |
| long p; |
| |
| if (this_round > CON_BUF_SIZE) |
| this_round = CON_BUF_SIZE; |
| |
| /* Temporarily drop the console lock so that we can read |
| * in the write data from userspace safely. |
| */ |
| release_console_sem(); |
| ret = copy_from_user(con_buf, buf, this_round); |
| acquire_console_sem(); |
| |
| if (ret) { |
| this_round -= ret; |
| if (!this_round) { |
| /* Abort loop if no data were copied. Otherwise |
| * fail with -EFAULT. |
| */ |
| if (written) |
| break; |
| ret = -EFAULT; |
| goto unlock_out; |
| } |
| } |
| |
| /* The vcs_size might have changed while we slept to grab |
| * the user buffer, so recheck. |
| * Return data written up to now on failure. |
| */ |
| size = vcs_size(inode); |
| if (pos >= size) |
| break; |
| if (this_round > size - pos) |
| this_round = size - pos; |
| |
| /* OK, now actually push the write to the console |
| * under the lock using the local kernel buffer. |
| */ |
| |
| con_buf0 = con_buf; |
| orig_count = this_round; |
| maxcol = vc->vc_cols; |
| p = pos; |
| if (!attr) { |
| org0 = org = screen_pos(vc, p, viewed); |
| col = p % maxcol; |
| p += maxcol - col; |
| |
| while (this_round > 0) { |
| unsigned char c = *con_buf0++; |
| |
| this_round--; |
| vcs_scr_writew(vc, |
| (vcs_scr_readw(vc, org) & 0xff00) | c, org); |
| org++; |
| if (++col == maxcol) { |
| org = screen_pos(vc, p, viewed); |
| col = 0; |
| p += maxcol; |
| } |
| } |
| } else { |
| if (p < HEADER_SIZE) { |
| char header[HEADER_SIZE]; |
| |
| getconsxy(vc, header + 2); |
| while (p < HEADER_SIZE && this_round > 0) { |
| this_round--; |
| header[p++] = *con_buf0++; |
| } |
| if (!viewed) |
| putconsxy(vc, header + 2); |
| } |
| p -= HEADER_SIZE; |
| col = (p/2) % maxcol; |
| if (this_round > 0) { |
| org0 = org = screen_pos(vc, p/2, viewed); |
| if ((p & 1) && this_round > 0) { |
| char c; |
| |
| this_round--; |
| c = *con_buf0++; |
| #ifdef __BIG_ENDIAN |
| vcs_scr_writew(vc, c | |
| (vcs_scr_readw(vc, org) & 0xff00), org); |
| #else |
| vcs_scr_writew(vc, (c << 8) | |
| (vcs_scr_readw(vc, org) & 0xff), org); |
| #endif |
| org++; |
| p++; |
| if (++col == maxcol) { |
| org = screen_pos(vc, p/2, viewed); |
| col = 0; |
| } |
| } |
| p /= 2; |
| p += maxcol - col; |
| } |
| while (this_round > 1) { |
| unsigned short w; |
| |
| w = get_unaligned(((unsigned short *)con_buf0)); |
| vcs_scr_writew(vc, w, org++); |
| con_buf0 += 2; |
| this_round -= 2; |
| if (++col == maxcol) { |
| org = screen_pos(vc, p, viewed); |
| col = 0; |
| p += maxcol; |
| } |
| } |
| if (this_round > 0) { |
| unsigned char c; |
| |
| c = *con_buf0++; |
| #ifdef __BIG_ENDIAN |
| vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org); |
| #else |
| vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org); |
| #endif |
| } |
| } |
| count -= orig_count; |
| written += orig_count; |
| buf += orig_count; |
| pos += orig_count; |
| if (org0) |
| update_region(vc, (unsigned long)(org0), org - org0); |
| } |
| *ppos += written; |
| ret = written; |
| |
| unlock_out: |
| release_console_sem(); |
| |
| up(&con_buf_sem); |
| |
| return ret; |
| } |
| |
| static int |
| vcs_open(struct inode *inode, struct file *filp) |
| { |
| unsigned int currcons = iminor(inode) & 127; |
| if(currcons && !vc_cons_allocated(currcons-1)) |
| return -ENXIO; |
| return 0; |
| } |
| |
| static struct file_operations vcs_fops = { |
| .llseek = vcs_lseek, |
| .read = vcs_read, |
| .write = vcs_write, |
| .open = vcs_open, |
| }; |
| |
| static struct class *vc_class; |
| |
| void vcs_make_devfs(struct tty_struct *tty) |
| { |
| class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1), |
| NULL, "vcs%u", tty->index + 1); |
| class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129), |
| NULL, "vcsa%u", tty->index + 1); |
| } |
| void vcs_remove_devfs(struct tty_struct *tty) |
| { |
| class_device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1)); |
| class_device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 129)); |
| } |
| |
| int __init vcs_init(void) |
| { |
| if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops)) |
| panic("unable to get major %d for vcs device", VCS_MAJOR); |
| vc_class = class_create(THIS_MODULE, "vc"); |
| |
| class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs"); |
| class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa"); |
| return 0; |
| } |