diff options
Diffstat (limited to 'drivers/char/vc_screen.c')
| -rw-r--r-- | drivers/char/vc_screen.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c new file mode 100644 index 000000000..f5f389cf8 --- /dev/null +++ b/drivers/char/vc_screen.c @@ -0,0 +1,212 @@ +/* + * 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) + * [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 + */ + +#include <linux/kernel.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/tty.h> +#include <linux/fs.h> +#include <asm/segment.h> +#include "vt_kern.h" +#include "selection.h" + +#define HEADER_SIZE 4 + +static inline int +vcs_size(struct inode *inode) +{ + int size = video_num_lines * video_num_columns; + if (MINOR(inode->i_rdev) & 128) + size = 2*size + HEADER_SIZE; + return size; +} + +static int +vcs_lseek(struct inode *inode, struct file *file, off_t offset, int orig) +{ + int size = vcs_size(inode); + + switch (orig) { + case 0: + file->f_pos = offset; + break; + case 1: + file->f_pos += offset; + break; + case 2: + file->f_pos = size + offset; + break; + default: + return -EINVAL; + } + if (file->f_pos < 0 || file->f_pos > size) + return -EINVAL; + return file->f_pos; +} + +static int +vcs_read(struct inode *inode, struct file *file, char *buf, int count) +{ + unsigned long p = file->f_pos; + unsigned int cons = MINOR(inode->i_rdev); + int viewed, attr, size, read; + char *buf0; + unsigned short *org; + + attr = (cons & 128); + cons = (cons & 127); + if (cons == 0) { + cons = fg_console; + viewed = 1; + } else { + cons--; + viewed = 0; + } + if (!vc_cons_allocated(cons)) + return -ENXIO; + + size = vcs_size(inode); + if (count < 0 || p > size) + return -EINVAL; + if (count > size - p) + count = size - p; + + buf0 = buf; + if (!attr) { + org = screen_pos(cons, p, viewed); + while (count-- > 0) + put_fs_byte(scr_readw(org++) & 0xff, buf++); + } else { + if (p < HEADER_SIZE) { + char header[HEADER_SIZE]; + header[0] = (char) video_num_lines; + header[1] = (char) video_num_columns; + getconsxy(cons, header+2); + while (p < HEADER_SIZE && count-- > 0) + put_fs_byte(header[p++], buf++); + } + p -= HEADER_SIZE; + org = screen_pos(cons, p/2, viewed); + if ((p & 1) && count-- > 0) + put_fs_byte(scr_readw(org++) >> 8, buf++); + while (count > 1) { + put_fs_word(scr_readw(org++), buf); + buf += 2; + count -= 2; + } + if (count > 0) + put_fs_byte(scr_readw(org) & 0xff, buf++); + } + read = buf - buf0; + file->f_pos += read; + return read; +} + +static int +vcs_write(struct inode *inode, struct file *file, char *buf, int count) +{ + unsigned long p = file->f_pos; + unsigned int cons = MINOR(inode->i_rdev); + int viewed, attr, size, written; + char *buf0; + unsigned short *org; + + attr = (cons & 128); + cons = (cons & 127); + if (cons == 0) { + cons = fg_console; + viewed = 1; + } else { + cons--; + viewed = 0; + } + if (!vc_cons_allocated(cons)) + return -ENXIO; + + size = vcs_size(inode); + if (count < 0 || p > size) + return -EINVAL; + if (count > size - p) + count = size - p; + + buf0 = buf; + if (!attr) { + org = screen_pos(cons, p, viewed); + while (count-- > 0) { + scr_writew((scr_readw(org) & 0xff00) | + get_fs_byte(buf++), org); + org++; + } + } else { + if (p < HEADER_SIZE) { + char header[HEADER_SIZE]; + getconsxy(cons, header+2); + while (p < HEADER_SIZE && count-- > 0) + header[p++] = get_fs_byte(buf++); + if (!viewed) + putconsxy(cons, header+2); + } + p -= HEADER_SIZE; + org = screen_pos(cons, p/2, viewed); + if ((p & 1) && count-- > 0) { + scr_writew((get_fs_byte(buf++) << 8) | + (scr_readw(org) & 0xff), org); + org++; + } + while (count > 1) { + scr_writew(get_fs_word(buf), org++); + buf += 2; + count -= 2; + } + if (count > 0) + scr_writew((scr_readw(org) & 0xff00) | + get_fs_byte(buf++), org); + } + written = buf - buf0; + file->f_pos += written; + return written; +} + +static int +vcs_open(struct inode *inode, struct file *filp) +{ + unsigned int cons = (MINOR(inode->i_rdev) & 127); + if(cons && !vc_cons_allocated(cons-1)) + return -ENXIO; + return 0; +} + +static struct file_operations vcs_fops = { + vcs_lseek, /* lseek */ + vcs_read, /* read */ + vcs_write, /* write */ + NULL, /* readdir */ + NULL, /* select */ + NULL, /* ioctl */ + NULL, /* mmap */ + vcs_open, /* open */ + NULL, /* release */ + NULL /* fsync */ +}; + +long vcs_init(long kmem_start) +{ + if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops)) + printk("unable to get major %d for vcs device", VCS_MAJOR); + return kmem_start; +} |