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[/] [test_project/] [trunk/] [linux_sd_driver/] [drivers/] [char/] [vc_screen.c] - Blame information for rev 62

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/*
 * 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/kernel.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/kbd_kern.h>
#include <linux/console.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;
 
        mutex_lock(&con_buf_mtx);
        size = vcs_size(file->f_path.dentry->d_inode);
        switch (orig) {
                default:
                        mutex_unlock(&con_buf_mtx);
                        return -EINVAL;
                case 2:
                        offset += size;
                        break;
                case 1:
                        offset += file->f_pos;
                case 0:
                        break;
        }
        if (offset < 0 || offset > size) {
                mutex_unlock(&con_buf_mtx);
                return -EINVAL;
        }
        file->f_pos = offset;
        mutex_unlock(&con_buf_mtx);
        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_path.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;
 
        mutex_lock(&con_buf_mtx);
 
        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();
        mutex_unlock(&con_buf_mtx);
        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_path.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;
 
        mutex_lock(&con_buf_mtx);
 
        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();
 
        mutex_unlock(&con_buf_mtx);
 
        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 const 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_sysfs(struct tty_struct *tty)
{
        device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1),
                        "vcs%u", tty->index + 1);
        device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129),
                        "vcsa%u", tty->index + 1);
}
 
void vcs_remove_sysfs(struct tty_struct *tty)
{
        device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1));
        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");
 
        device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), "vcs");
        device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), "vcsa");
        return 0;
}

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[/] [test_project/] [trunk/] [linux_sd_driver/] [drivers/] [char/] [vc_screen.c] - Blame information for rev 62

Line No.	Rev	Author	Line
1	62	marcus.erl	`/*`
2			`* linux/drivers/char/vc_screen.c`
3			`*`
4			`* Provide access to virtual console memory.`
5			`* /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)`
6			`* /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)`
7			`* [minor: N]`
8			`*`
9			`* /dev/vcsaN: idem, but including attributes, and prefixed with`
10			`* the 4 bytes lines,columns,x,y (as screendump used to give).`
11			`* Attribute/character pair is in native endianity.`
12			`* [minor: N+128]`
13			`*`
14			`* This replaces screendump and part of selection, so that the system`
15			`* administrator can control access using file system permissions.`
16			`*`
17			`* aeb@cwi.nl - efter Friedas begravelse - 950211`
18			`*`
19			`* machek@k332.feld.cvut.cz - modified not to send characters to wrong console`
20			`* - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)`
21			`* - making it shorter - scr_readw are macros which expand in PRETTY long code`
22			`*/`
23
24			`#include <linux/kernel.h>`
25			`#include <linux/major.h>`
26			`#include <linux/errno.h>`
27			`#include <linux/tty.h>`
28			`#include <linux/interrupt.h>`
29			`#include <linux/mm.h>`
30			`#include <linux/init.h>`
31			`#include <linux/mutex.h>`
32			`#include <linux/vt_kern.h>`
33			`#include <linux/selection.h>`
34			`#include <linux/kbd_kern.h>`
35			`#include <linux/console.h>`
36			`#include <linux/device.h>`
37
38			`#include <asm/uaccess.h>`
39			`#include <asm/byteorder.h>`
40			`#include <asm/unaligned.h>`
41
42			`#undef attr`
43			`#undef org`
44			`#undef addr`
45			`#define HEADER_SIZE 4`
46
47			`static int`
48			`vcs_size(struct inode *inode)`
49			`{`
50			`int size;`
51			`int minor = iminor(inode);`
52			`int currcons = minor & 127;`
53			`struct vc_data *vc;`
54
55			`if (currcons == 0)`
56			`currcons = fg_console;`
57			`else`
58			`currcons--;`
59			`if (!vc_cons_allocated(currcons))`
60			`return -ENXIO;`
61			`vc = vc_cons[currcons].d;`
62
63			`size = vc->vc_rows * vc->vc_cols;`
64
65			`if (minor & 128)`
66			`size = 2*size + HEADER_SIZE;`
67			`return size;`
68			`}`
69
70			`static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)`
71			`{`
72			`int size;`
73
74			`mutex_lock(&con_buf_mtx);`
75			`size = vcs_size(file->f_path.dentry->d_inode);`
76			`switch (orig) {`
77			`default:`
78			`mutex_unlock(&con_buf_mtx);`
79			`return -EINVAL;`
80			`case 2:`
81			`offset += size;`
82			`break;`
83			`case 1:`
84			`offset += file->f_pos;`
85			`case 0:`
86			`break;`
87			`}`
88			`if (offset < 0 \|\| offset > size) {`
89			`mutex_unlock(&con_buf_mtx);`
90			`return -EINVAL;`
91			`}`
92			`file->f_pos = offset;`
93			`mutex_unlock(&con_buf_mtx);`
94			`return file->f_pos;`
95			`}`
96
97
98			`static ssize_t`
99			`vcs_read(struct file file, char __user buf, size_t count, loff_t *ppos)`
100			`{`
101			`struct inode *inode = file->f_path.dentry->d_inode;`
102			`unsigned int currcons = iminor(inode);`
103			`struct vc_data *vc;`
104			`long pos;`
105			`long viewed, attr, read;`
106			`int col, maxcol;`
107			`unsigned short *org = NULL;`
108			`ssize_t ret;`
109
110			`mutex_lock(&con_buf_mtx);`
111
112			`pos = *ppos;`
113
114			`/* Select the proper current console and verify`
115			`* sanity of the situation under the console lock.`
116			`*/`
117			`acquire_console_sem();`
118
119			`attr = (currcons & 128);`
120			`currcons = (currcons & 127);`
121			`if (currcons == 0) {`
122			`currcons = fg_console;`
123			`viewed = 1;`
124			`} else {`
125			`currcons--;`
126			`viewed = 0;`
127			`}`
128			`ret = -ENXIO;`
129			`if (!vc_cons_allocated(currcons))`
130			`goto unlock_out;`
131			`vc = vc_cons[currcons].d;`
132
133			`ret = -EINVAL;`
134			`if (pos < 0)`
135			`goto unlock_out;`
136			`read = 0;`
137			`ret = 0;`
138			`while (count) {`
139			`char con_buf0, con_buf_start;`
140			`long this_round, size;`
141			`ssize_t orig_count;`
142			`long p = pos;`
143
144			`/* Check whether we are above size each round,`
145			`* as copy_to_user at the end of this loop`
146			`* could sleep.`
147			`*/`
148			`size = vcs_size(inode);`
149			`if (pos >= size)`
150			`break;`
151			`if (count > size - pos)`
152			`count = size - pos;`
153
154			`this_round = count;`
155			`if (this_round > CON_BUF_SIZE)`
156			`this_round = CON_BUF_SIZE;`
157
158			`/* Perform the whole read into the local con_buf.`
159			`* Then we can drop the console spinlock and safely`
160			`* attempt to move it to userspace.`
161			`*/`
162
163			`con_buf_start = con_buf0 = con_buf;`
164			`orig_count = this_round;`
165			`maxcol = vc->vc_cols;`
166			`if (!attr) {`
167			`org = screen_pos(vc, p, viewed);`
168			`col = p % maxcol;`
169			`p += maxcol - col;`
170			`while (this_round-- > 0) {`
171			`*con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);`
172			`if (++col == maxcol) {`
173			`org = screen_pos(vc, p, viewed);`
174			`col = 0;`
175			`p += maxcol;`
176			`}`
177			`}`
178			`} else {`
179			`if (p < HEADER_SIZE) {`
180			`size_t tmp_count;`
181
182			`con_buf0[0] = (char)vc->vc_rows;`
183			`con_buf0[1] = (char)vc->vc_cols;`
184			`getconsxy(vc, con_buf0 + 2);`
185
186			`con_buf_start += p;`
187			`this_round += p;`
188			`if (this_round > CON_BUF_SIZE) {`
189			`this_round = CON_BUF_SIZE;`
190			`orig_count = this_round - p;`
191			`}`
192
193			`tmp_count = HEADER_SIZE;`
194			`if (tmp_count > this_round)`
195			`tmp_count = this_round;`
196
197			`/* Advance state pointers and move on. */`
198			`this_round -= tmp_count;`
199			`p = HEADER_SIZE;`
200			`con_buf0 = con_buf + HEADER_SIZE;`
201			`/* If this_round >= 0, then p is even... */`
202			`} else if (p & 1) {`
203			`/* Skip first byte for output if start address is odd`
204			`* Update region sizes up/down depending on free`
205			`* space in buffer.`
206			`*/`
207			`con_buf_start++;`
208			`if (this_round < CON_BUF_SIZE)`
209			`this_round++;`
210			`else`
211			`orig_count--;`
212			`}`
213			`if (this_round > 0) {`
214			`unsigned short tmp_buf = (unsigned short )con_buf0;`
215
216			`p -= HEADER_SIZE;`
217			`p /= 2;`
218			`col = p % maxcol;`
219
220			`org = screen_pos(vc, p, viewed);`
221			`p += maxcol - col;`
222
223			`/* Buffer has even length, so we can always copy`
224			`* character + attribute. We do not copy last byte`
225			`* to userspace if this_round is odd.`
226			`*/`
227			`this_round = (this_round + 1) >> 1;`
228
229			`while (this_round) {`
230			`*tmp_buf++ = vcs_scr_readw(vc, org++);`
231			`this_round --;`
232			`if (++col == maxcol) {`
233			`org = screen_pos(vc, p, viewed);`
234			`col = 0;`
235			`p += maxcol;`
236			`}`
237			`}`
238			`}`
239			`}`
240
241			`/* Finally, release the console semaphore while we push`
242			`* all the data to userspace from our temporary buffer.`
243			`*`
244			`* AKPM: Even though it's a semaphore, we should drop it because`
245			`* the pagefault handling code may want to call printk().`
246			`*/`
247
248			`release_console_sem();`
249			`ret = copy_to_user(buf, con_buf_start, orig_count);`
250			`acquire_console_sem();`
251
252			`if (ret) {`
253			`read += (orig_count - ret);`
254			`ret = -EFAULT;`
255			`break;`
256			`}`
257			`buf += orig_count;`
258			`pos += orig_count;`
259			`read += orig_count;`
260			`count -= orig_count;`
261			`}`
262			`*ppos += read;`
263			`if (read)`
264			`ret = read;`
265			`unlock_out:`
266			`release_console_sem();`
267			`mutex_unlock(&con_buf_mtx);`
268			`return ret;`
269			`}`
270
271			`static ssize_t`
272			`vcs_write(struct file file, const char __user buf, size_t count, loff_t *ppos)`
273			`{`
274			`struct inode *inode = file->f_path.dentry->d_inode;`
275			`unsigned int currcons = iminor(inode);`
276			`struct vc_data *vc;`
277			`long pos;`
278			`long viewed, attr, size, written;`
279			`char *con_buf0;`
280			`int col, maxcol;`
281			`u16 org0 = NULL, org = NULL;`
282			`size_t ret;`
283
284			`mutex_lock(&con_buf_mtx);`
285
286			`pos = *ppos;`
287
288			`/* Select the proper current console and verify`
289			`* sanity of the situation under the console lock.`
290			`*/`
291			`acquire_console_sem();`
292
293			`attr = (currcons & 128);`
294			`currcons = (currcons & 127);`
295
296			`if (currcons == 0) {`
297			`currcons = fg_console;`
298			`viewed = 1;`
299			`} else {`
300			`currcons--;`
301			`viewed = 0;`
302			`}`
303			`ret = -ENXIO;`
304			`if (!vc_cons_allocated(currcons))`
305			`goto unlock_out;`
306			`vc = vc_cons[currcons].d;`
307
308			`size = vcs_size(inode);`
309			`ret = -EINVAL;`
310			`if (pos < 0 \|\| pos > size)`
311			`goto unlock_out;`
312			`if (count > size - pos)`
313			`count = size - pos;`
314			`written = 0;`
315			`while (count) {`
316			`long this_round = count;`
317			`size_t orig_count;`
318			`long p;`
319
320			`if (this_round > CON_BUF_SIZE)`
321			`this_round = CON_BUF_SIZE;`
322
323			`/* Temporarily drop the console lock so that we can read`
324			`* in the write data from userspace safely.`
325			`*/`
326			`release_console_sem();`
327			`ret = copy_from_user(con_buf, buf, this_round);`
328			`acquire_console_sem();`
329
330			`if (ret) {`
331			`this_round -= ret;`
332			`if (!this_round) {`
333			`/* Abort loop if no data were copied. Otherwise`
334			`* fail with -EFAULT.`
335			`*/`
336			`if (written)`
337			`break;`
338			`ret = -EFAULT;`
339			`goto unlock_out;`
340			`}`
341			`}`
342
343			`/* The vcs_size might have changed while we slept to grab`
344			`* the user buffer, so recheck.`
345			`* Return data written up to now on failure.`
346			`*/`
347			`size = vcs_size(inode);`
348			`if (pos >= size)`
349			`break;`
350			`if (this_round > size - pos)`
351			`this_round = size - pos;`
352
353			`/* OK, now actually push the write to the console`
354			`* under the lock using the local kernel buffer.`
355			`*/`
356
357			`con_buf0 = con_buf;`
358			`orig_count = this_round;`
359			`maxcol = vc->vc_cols;`
360			`p = pos;`
361			`if (!attr) {`
362			`org0 = org = screen_pos(vc, p, viewed);`
363			`col = p % maxcol;`
364			`p += maxcol - col;`
365
366			`while (this_round > 0) {`
367			`unsigned char c = *con_buf0++;`
368
369			`this_round--;`
370			`vcs_scr_writew(vc,`
371			`(vcs_scr_readw(vc, org) & 0xff00) \| c, org);`
372			`org++;`
373			`if (++col == maxcol) {`
374			`org = screen_pos(vc, p, viewed);`
375			`col = 0;`
376			`p += maxcol;`
377			`}`
378			`}`
379			`} else {`
380			`if (p < HEADER_SIZE) {`
381			`char header[HEADER_SIZE];`
382
383			`getconsxy(vc, header + 2);`
384			`while (p < HEADER_SIZE && this_round > 0) {`
385			`this_round--;`
386			`header[p++] = *con_buf0++;`
387			`}`
388			`if (!viewed)`
389			`putconsxy(vc, header + 2);`
390			`}`
391			`p -= HEADER_SIZE;`
392			`col = (p/2) % maxcol;`
393			`if (this_round > 0) {`
394			`org0 = org = screen_pos(vc, p/2, viewed);`
395			`if ((p & 1) && this_round > 0) {`
396			`char c;`
397
398			`this_round--;`
399			`c = *con_buf0++;`
400			`#ifdef __BIG_ENDIAN`
401			`vcs_scr_writew(vc, c \|`
402			`(vcs_scr_readw(vc, org) & 0xff00), org);`
403			`#else`
404			`vcs_scr_writew(vc, (c << 8) \|`
405			`(vcs_scr_readw(vc, org) & 0xff), org);`
406			`#endif`
407			`org++;`
408			`p++;`
409			`if (++col == maxcol) {`
410			`org = screen_pos(vc, p/2, viewed);`
411			`col = 0;`
412			`}`
413			`}`
414			`p /= 2;`
415			`p += maxcol - col;`
416			`}`
417			`while (this_round > 1) {`
418			`unsigned short w;`
419
420			`w = get_unaligned(((unsigned short *)con_buf0));`
421			`vcs_scr_writew(vc, w, org++);`
422			`con_buf0 += 2;`
423			`this_round -= 2;`
424			`if (++col == maxcol) {`
425			`org = screen_pos(vc, p, viewed);`
426			`col = 0;`
427			`p += maxcol;`
428			`}`
429			`}`
430			`if (this_round > 0) {`
431			`unsigned char c;`
432
433			`c = *con_buf0++;`
434			`#ifdef __BIG_ENDIAN`
435			`vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) \| (c << 8), org);`
436			`#else`
437			`vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) \| c, org);`
438			`#endif`
439			`}`
440			`}`
441			`count -= orig_count;`
442			`written += orig_count;`
443			`buf += orig_count;`
444			`pos += orig_count;`
445			`if (org0)`
446			`update_region(vc, (unsigned long)(org0), org - org0);`
447			`}`
448			`*ppos += written;`
449			`ret = written;`
450
451			`unlock_out:`
452			`release_console_sem();`
453
454			`mutex_unlock(&con_buf_mtx);`
455
456			`return ret;`
457			`}`
458
459			`static int`
460			`vcs_open(struct inode inode, struct file filp)`
461			`{`
462			`unsigned int currcons = iminor(inode) & 127;`
463			`if(currcons && !vc_cons_allocated(currcons-1))`
464			`return -ENXIO;`
465			`return 0;`
466			`}`
467
468			`static const struct file_operations vcs_fops = {`
469			`.llseek = vcs_lseek,`
470			`.read = vcs_read,`
471			`.write = vcs_write,`
472			`.open = vcs_open,`
473			`};`
474
475			`static struct class *vc_class;`
476
477			`void vcs_make_sysfs(struct tty_struct *tty)`
478			`{`
479			`device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1),`
480			`"vcs%u", tty->index + 1);`
481			`device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129),`
482			`"vcsa%u", tty->index + 1);`
483			`}`
484
485			`void vcs_remove_sysfs(struct tty_struct *tty)`
486			`{`
487			`device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1));`
488			`device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 129));`
489			`}`
490
491			`int __init vcs_init(void)`
492			`{`
493			`if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))`
494			`panic("unable to get major %d for vcs device", VCS_MAJOR);`
495			`vc_class = class_create(THIS_MODULE, "vc");`
496
497			`device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), "vcs");`
498			`device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), "vcsa");`
499			`return 0;`
500			`}`