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[/] [or1k/] [tags/] [before_ORP/] [uclinux/] [uClinux-2.0.x/] [drivers/] [char/] [vc_screen.c] - Rev 1765
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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) * [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_user(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_user(header[p++], buf++); } p -= HEADER_SIZE; org = screen_pos(cons, p/2, viewed); if ((p & 1) && count-- > 0) put_user(scr_readw(org++) >> 8, buf++); while (count > 1) { put_user(scr_readw(org++), (unsigned short *) buf); buf += 2; count -= 2; } if (count > 0) put_user(scr_readw(org) & 0xff, buf++); } read = buf - buf0; file->f_pos += read; return read; } static int vcs_write(struct inode *inode, struct file *file, const char *buf, int count) { unsigned long p = file->f_pos; unsigned int cons = MINOR(inode->i_rdev); int viewed, attr, size, written; const 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_user((const unsigned char*)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_user(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_user(buf++) << 8) | (scr_readw(org) & 0xff), org); org++; } while (count > 1) { scr_writew(get_user((const unsigned short *) buf), org++); buf += 2; count -= 2; } if (count > 0) scr_writew((scr_readw(org) & 0xff00) | get_user((const unsigned char*)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 */ }; int vcs_init(void) { int error; error = register_chrdev(VCS_MAJOR, "vcs", &vcs_fops); if (error) printk("unable to get major %d for vcs device", VCS_MAJOR); return error; }