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Diffstat (limited to 'drivers/char/vc_screen.c')
-rw-r--r--drivers/char/vc_screen.c509
1 files changed, 509 insertions, 0 deletions
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c
new file mode 100644
index 00000000000..7abe405b865
--- /dev/null
+++ b/drivers/char/vc_screen.c
@@ -0,0 +1,509 @@
+/*
+ * 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(((const 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_simple *vc_class;
+
+void vcs_make_devfs(struct tty_struct *tty)
+{
+ devfs_mk_cdev(MKDEV(VCS_MAJOR, tty->index + 1),
+ S_IFCHR|S_IRUSR|S_IWUSR,
+ "vcc/%u", tty->index + 1);
+ devfs_mk_cdev(MKDEV(VCS_MAJOR, tty->index + 129),
+ S_IFCHR|S_IRUSR|S_IWUSR,
+ "vcc/a%u", tty->index + 1);
+ class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, tty->index + 1), NULL, "vcs%u", tty->index + 1);
+ class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, tty->index + 129), NULL, "vcsa%u", tty->index + 1);
+}
+void vcs_remove_devfs(struct tty_struct *tty)
+{
+ devfs_remove("vcc/%u", tty->index + 1);
+ devfs_remove("vcc/a%u", tty->index + 1);
+ class_simple_device_remove(MKDEV(VCS_MAJOR, tty->index + 1));
+ class_simple_device_remove(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_simple_create(THIS_MODULE, "vc");
+
+ devfs_mk_cdev(MKDEV(VCS_MAJOR, 0), S_IFCHR|S_IRUSR|S_IWUSR, "vcc/0");
+ devfs_mk_cdev(MKDEV(VCS_MAJOR, 128), S_IFCHR|S_IRUSR|S_IWUSR, "vcc/a0");
+ class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
+ class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
+ return 0;
+}
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