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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [drivers/] [char/] [vc_screen.c] - Blame information for rev 1777

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Line No. Rev Author Line
1 1626 jcastillo 
/*
2 
 * linux/drivers/char/vc_screen.c
3 
 *
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 * Provide access to virtual console memory.
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 * /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
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 * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
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 *            [minor: N]
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 *
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 * /dev/vcsaN: idem, but including attributes, and prefixed with
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 *      the 4 bytes lines,columns,x,y (as screendump used to give)
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 *            [minor: N+128]
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 *
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 * This replaces screendump and part of selection, so that the system
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 * administrator can control access using file system permissions.
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 *
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 * aeb@cwi.nl - efter Friedas begravelse - 950211
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 */
18 
 
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#include <linux/kernel.h>
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#include <linux/major.h>
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#include <linux/errno.h>
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#include <linux/tty.h>
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#include <linux/fs.h>
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#include <asm/segment.h>
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#include "vt_kern.h"
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#include "selection.h"
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#define HEADER_SIZE     4
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static inline int
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vcs_size(struct inode *inode)
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{
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        int size = video_num_lines * video_num_columns;
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        if (MINOR(inode->i_rdev) & 128)
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                size = 2*size + HEADER_SIZE;
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        return size;
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}
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static int
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vcs_lseek(struct inode *inode, struct file *file, off_t offset, int orig)
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{
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        int size = vcs_size(inode);
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        switch (orig) {
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                case 0:
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                        file->f_pos = offset;
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                        break;
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                case 1:
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                        file->f_pos += offset;
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                        break;
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                case 2:
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                        file->f_pos = size + offset;
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                        break;
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                default:
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                        return -EINVAL;
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        }
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        if (file->f_pos < 0 || file->f_pos > size)
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                return -EINVAL;
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        return file->f_pos;
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}
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static int
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vcs_read(struct inode *inode, struct file *file, char *buf, int count)
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{
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        unsigned long p = file->f_pos;
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        unsigned int cons = MINOR(inode->i_rdev);
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        int viewed, attr, size, read;
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        char *buf0;
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        unsigned short *org;
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        attr = (cons & 128);
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        cons = (cons & 127);
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        if (cons == 0) {
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                cons = fg_console;
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                viewed = 1;
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        } else {
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                cons--;
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                viewed = 0;
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        }
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        if (!vc_cons_allocated(cons))
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                return -ENXIO;
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        size = vcs_size(inode);
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        if (count < 0 || p > size)
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                return -EINVAL;
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        if (count > size - p)
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                count = size - p;
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        buf0 = buf;
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        if (!attr) {
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                org = screen_pos(cons, p, viewed);
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                while (count-- > 0)
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                        put_user(scr_readw(org++) & 0xff, buf++);
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        } else {
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                if (p < HEADER_SIZE) {
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                        char header[HEADER_SIZE];
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                        header[0] = (char) video_num_lines;
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                        header[1] = (char) video_num_columns;
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                        getconsxy(cons, header+2);
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                        while (p < HEADER_SIZE && count-- > 0)
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                            put_user(header[p++], buf++);
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                }
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                p -= HEADER_SIZE;
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                org = screen_pos(cons, p/2, viewed);
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                if ((p & 1) && count-- > 0)
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                        put_user(scr_readw(org++) >> 8, buf++);
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                while (count > 1) {
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                        put_user(scr_readw(org++), (unsigned short *) buf);
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                        buf += 2;
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                        count -= 2;
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                }
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                if (count > 0)
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                        put_user(scr_readw(org) & 0xff, buf++);
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        }
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        read = buf - buf0;
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        file->f_pos += read;
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        return read;
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}
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static int
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vcs_write(struct inode *inode, struct file *file, const char *buf, int count)
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{
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        unsigned long p = file->f_pos;
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        unsigned int cons = MINOR(inode->i_rdev);
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        int viewed, attr, size, written;
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        const char *buf0;
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        unsigned short *org;
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        attr = (cons & 128);
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        cons = (cons & 127);
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        if (cons == 0) {
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                cons = fg_console;
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                viewed = 1;
134 
        } else {
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                cons--;
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                viewed = 0;
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        }
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        if (!vc_cons_allocated(cons))
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                return -ENXIO;
140 
 
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        size = vcs_size(inode);
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        if (count < 0 || p > size)
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                return -EINVAL;
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        if (count > size - p)
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                count = size - p;
146 
 
147 
        buf0 = buf;
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        if (!attr) {
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                org = screen_pos(cons, p, viewed);
150 
                while (count-- > 0) {
151 
                        scr_writew((scr_readw(org) & 0xff00) |
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                                   get_user((const unsigned char*)buf++), org);
153 
                        org++;
154 
                }
155 
        } else {
156 
                if (p < HEADER_SIZE) {
157 
                        char header[HEADER_SIZE];
158 
                        getconsxy(cons, header+2);
159 
                        while (p < HEADER_SIZE && count-- > 0)
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                                header[p++] = get_user(buf++);
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                        if (!viewed)
162 
                                putconsxy(cons, header+2);
163 
                }
164 
                p -= HEADER_SIZE;
165 
                org = screen_pos(cons, p/2, viewed);
166 
                if ((p & 1) && count-- > 0) {
167 
                        scr_writew((get_user(buf++) << 8) |
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                                   (scr_readw(org) & 0xff), org);
169 
                        org++;
170 
                }
171 
                while (count > 1) {
172 
                        scr_writew(get_user((const unsigned short *) buf), org++);
173 
                        buf += 2;
174 
                        count -= 2;
175 
                }
176 
                if (count > 0)
177 
                        scr_writew((scr_readw(org) & 0xff00) |
178 
                                   get_user((const unsigned char*)buf++), org);
179 
        }
180 
        written = buf - buf0;
181 
        file->f_pos += written;
182 
        return written;
183 
}
184 
 
185 
static int
186 
vcs_open(struct inode *inode, struct file *filp)
187 
{
188 
        unsigned int cons = (MINOR(inode->i_rdev) & 127);
189 
        if(cons && !vc_cons_allocated(cons-1))
190 
                return -ENXIO;
191 
        return 0;
192 
}
193 
 
194 
static struct file_operations vcs_fops = {
195 
        vcs_lseek,      /* lseek */
196 
        vcs_read,       /* read */
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        vcs_write,      /* write */
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        NULL,           /* readdir */
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        NULL,           /* select */
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        NULL,           /* ioctl */
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        NULL,           /* mmap */
202 
        vcs_open,       /* open */
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        NULL,           /* release */
204 
        NULL            /* fsync */
205 
};
206 
 
207 
int vcs_init(void)
208 
{
209 
        int error;
210 
 
211 
        error = register_chrdev(VCS_MAJOR, "vcs", &vcs_fops);
212 
        if (error)
213 
                printk("unable to get major %d for vcs device", VCS_MAJOR);
214 
        return error;
215 
}

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