forked from Minki/linux
24a89d1cb6
Although line discipline receiving is single-producer/single-consumer, using tty->receive_room to manage flow control creates unnecessary critical regions requiring additional lock use. Instead, introduce the optional .receive_buf2() ldisc method which returns the # of bytes actually received. Serialization is guaranteed by the caller. In turn, the line discipline should schedule the buffer work item whenever space becomes available; ie., when there is room to receive data and receive_room() previously returned 0 (the buffer work item stops processing if receive_buf2() returns 0). Note the 'no room' state need not be atomic despite concurrent use by two threads because only the buffer work thread can set the state and only the read() thread can clear the state. Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY. Provide a public helper function, tty_ldisc_receive_buf(), to use when directly accessing the receive_buf() methods. Line disciplines not using input flow control can continue to set tty->receive_room to a fixed value and only provide the receive_buf() method. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
369 lines
9.2 KiB
C
369 lines
9.2 KiB
C
/*
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* This module exports the functions:
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*
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* 'int set_selection(struct tiocl_selection __user *, struct tty_struct *)'
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* 'void clear_selection(void)'
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* 'int paste_selection(struct tty_struct *)'
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* 'int sel_loadlut(char __user *)'
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*
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* Now that /dev/vcs exists, most of this can disappear again.
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*/
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#include <linux/module.h>
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#include <linux/tty.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <asm/uaccess.h>
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#include <linux/kbd_kern.h>
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#include <linux/vt_kern.h>
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#include <linux/consolemap.h>
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#include <linux/selection.h>
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#include <linux/tiocl.h>
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#include <linux/console.h>
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/* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
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#define isspace(c) ((c) == ' ')
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extern void poke_blanked_console(void);
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/* FIXME: all this needs locking */
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/* Variables for selection control. */
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/* Use a dynamic buffer, instead of static (Dec 1994) */
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struct vc_data *sel_cons; /* must not be deallocated */
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static int use_unicode;
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static volatile int sel_start = -1; /* cleared by clear_selection */
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static int sel_end;
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static int sel_buffer_lth;
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static char *sel_buffer;
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/* clear_selection, highlight and highlight_pointer can be called
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from interrupt (via scrollback/front) */
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/* set reverse video on characters s-e of console with selection. */
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static inline void highlight(const int s, const int e)
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{
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invert_screen(sel_cons, s, e-s+2, 1);
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}
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/* use complementary color to show the pointer */
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static inline void highlight_pointer(const int where)
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{
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complement_pos(sel_cons, where);
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}
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static u16
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sel_pos(int n)
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{
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return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
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use_unicode);
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}
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/**
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* clear_selection - remove current selection
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*
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* Remove the current selection highlight, if any from the console
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* holding the selection. The caller must hold the console lock.
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*/
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void clear_selection(void)
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{
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highlight_pointer(-1); /* hide the pointer */
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if (sel_start != -1) {
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highlight(sel_start, sel_end);
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sel_start = -1;
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}
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}
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/*
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* User settable table: what characters are to be considered alphabetic?
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* 256 bits. Locked by the console lock.
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*/
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static u32 inwordLut[8]={
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0x00000000, /* control chars */
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0x03FF0000, /* digits */
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0x87FFFFFE, /* uppercase and '_' */
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0x07FFFFFE, /* lowercase */
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0x00000000,
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0x00000000,
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0xFF7FFFFF, /* latin-1 accented letters, not multiplication sign */
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0xFF7FFFFF /* latin-1 accented letters, not division sign */
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};
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static inline int inword(const u16 c) {
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return c > 0xff || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
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}
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/**
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* set loadlut - load the LUT table
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* @p: user table
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*
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* Load the LUT table from user space. The caller must hold the console
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* lock. Make a temporary copy so a partial update doesn't make a mess.
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*/
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int sel_loadlut(char __user *p)
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{
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u32 tmplut[8];
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if (copy_from_user(tmplut, (u32 __user *)(p+4), 32))
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return -EFAULT;
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memcpy(inwordLut, tmplut, 32);
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return 0;
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}
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/* does screen address p correspond to character at LH/RH edge of screen? */
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static inline int atedge(const int p, int size_row)
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{
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return (!(p % size_row) || !((p + 2) % size_row));
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}
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/* constrain v such that v <= u */
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static inline unsigned short limit(const unsigned short v, const unsigned short u)
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{
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return (v > u) ? u : v;
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}
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/* stores the char in UTF8 and returns the number of bytes used (1-3) */
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static int store_utf8(u16 c, char *p)
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{
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if (c < 0x80) {
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/* 0******* */
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p[0] = c;
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return 1;
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} else if (c < 0x800) {
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/* 110***** 10****** */
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p[0] = 0xc0 | (c >> 6);
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p[1] = 0x80 | (c & 0x3f);
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return 2;
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} else {
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/* 1110**** 10****** 10****** */
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p[0] = 0xe0 | (c >> 12);
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p[1] = 0x80 | ((c >> 6) & 0x3f);
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p[2] = 0x80 | (c & 0x3f);
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return 3;
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}
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}
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/**
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* set_selection - set the current selection.
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* @sel: user selection info
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* @tty: the console tty
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*
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* Invoked by the ioctl handle for the vt layer.
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*
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* The entire selection process is managed under the console_lock. It's
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* a lot under the lock but its hardly a performance path
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*/
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int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
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{
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struct vc_data *vc = vc_cons[fg_console].d;
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int sel_mode, new_sel_start, new_sel_end, spc;
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char *bp, *obp;
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int i, ps, pe, multiplier;
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u16 c;
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int mode;
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poke_blanked_console();
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{ unsigned short xs, ys, xe, ye;
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if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
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return -EFAULT;
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__get_user(xs, &sel->xs);
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__get_user(ys, &sel->ys);
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__get_user(xe, &sel->xe);
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__get_user(ye, &sel->ye);
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__get_user(sel_mode, &sel->sel_mode);
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xs--; ys--; xe--; ye--;
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xs = limit(xs, vc->vc_cols - 1);
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ys = limit(ys, vc->vc_rows - 1);
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xe = limit(xe, vc->vc_cols - 1);
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ye = limit(ye, vc->vc_rows - 1);
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ps = ys * vc->vc_size_row + (xs << 1);
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pe = ye * vc->vc_size_row + (xe << 1);
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if (sel_mode == TIOCL_SELCLEAR) {
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/* useful for screendump without selection highlights */
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clear_selection();
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return 0;
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}
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if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
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mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
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return 0;
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}
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}
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if (ps > pe) /* make sel_start <= sel_end */
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{
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int tmp = ps;
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ps = pe;
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pe = tmp;
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}
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if (sel_cons != vc_cons[fg_console].d) {
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clear_selection();
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sel_cons = vc_cons[fg_console].d;
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}
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mode = vt_do_kdgkbmode(fg_console);
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if (mode == K_UNICODE)
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use_unicode = 1;
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else
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use_unicode = 0;
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switch (sel_mode)
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{
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case TIOCL_SELCHAR: /* character-by-character selection */
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new_sel_start = ps;
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new_sel_end = pe;
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break;
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case TIOCL_SELWORD: /* word-by-word selection */
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spc = isspace(sel_pos(ps));
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for (new_sel_start = ps; ; ps -= 2)
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{
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if ((spc && !isspace(sel_pos(ps))) ||
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(!spc && !inword(sel_pos(ps))))
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break;
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new_sel_start = ps;
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if (!(ps % vc->vc_size_row))
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break;
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}
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spc = isspace(sel_pos(pe));
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for (new_sel_end = pe; ; pe += 2)
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{
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if ((spc && !isspace(sel_pos(pe))) ||
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(!spc && !inword(sel_pos(pe))))
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break;
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new_sel_end = pe;
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if (!((pe + 2) % vc->vc_size_row))
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break;
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}
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break;
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case TIOCL_SELLINE: /* line-by-line selection */
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new_sel_start = ps - ps % vc->vc_size_row;
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new_sel_end = pe + vc->vc_size_row
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- pe % vc->vc_size_row - 2;
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break;
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case TIOCL_SELPOINTER:
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highlight_pointer(pe);
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return 0;
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default:
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return -EINVAL;
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}
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/* remove the pointer */
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highlight_pointer(-1);
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/* select to end of line if on trailing space */
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if (new_sel_end > new_sel_start &&
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!atedge(new_sel_end, vc->vc_size_row) &&
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isspace(sel_pos(new_sel_end))) {
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for (pe = new_sel_end + 2; ; pe += 2)
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if (!isspace(sel_pos(pe)) ||
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atedge(pe, vc->vc_size_row))
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break;
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if (isspace(sel_pos(pe)))
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new_sel_end = pe;
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}
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if (sel_start == -1) /* no current selection */
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highlight(new_sel_start, new_sel_end);
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else if (new_sel_start == sel_start)
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{
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if (new_sel_end == sel_end) /* no action required */
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return 0;
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else if (new_sel_end > sel_end) /* extend to right */
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highlight(sel_end + 2, new_sel_end);
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else /* contract from right */
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highlight(new_sel_end + 2, sel_end);
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}
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else if (new_sel_end == sel_end)
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{
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if (new_sel_start < sel_start) /* extend to left */
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highlight(new_sel_start, sel_start - 2);
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else /* contract from left */
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highlight(sel_start, new_sel_start - 2);
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}
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else /* some other case; start selection from scratch */
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{
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clear_selection();
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highlight(new_sel_start, new_sel_end);
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}
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sel_start = new_sel_start;
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sel_end = new_sel_end;
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/* Allocate a new buffer before freeing the old one ... */
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multiplier = use_unicode ? 3 : 1; /* chars can take up to 3 bytes */
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bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
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if (!bp) {
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printk(KERN_WARNING "selection: kmalloc() failed\n");
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clear_selection();
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return -ENOMEM;
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}
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kfree(sel_buffer);
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sel_buffer = bp;
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obp = bp;
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for (i = sel_start; i <= sel_end; i += 2) {
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c = sel_pos(i);
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if (use_unicode)
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bp += store_utf8(c, bp);
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else
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*bp++ = c;
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if (!isspace(c))
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obp = bp;
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if (! ((i + 2) % vc->vc_size_row)) {
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/* strip trailing blanks from line and add newline,
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unless non-space at end of line. */
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if (obp != bp) {
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bp = obp;
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*bp++ = '\r';
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}
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obp = bp;
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}
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}
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sel_buffer_lth = bp - sel_buffer;
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return 0;
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}
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/* Insert the contents of the selection buffer into the
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* queue of the tty associated with the current console.
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* Invoked by ioctl().
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*
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* Locking: called without locks. Calls the ldisc wrongly with
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* unsafe methods,
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*/
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int paste_selection(struct tty_struct *tty)
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{
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struct vc_data *vc = tty->driver_data;
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int pasted = 0;
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unsigned int count;
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struct tty_ldisc *ld;
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DECLARE_WAITQUEUE(wait, current);
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console_lock();
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poke_blanked_console();
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console_unlock();
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ld = tty_ldisc_ref_wait(tty);
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/* FIXME: this is completely unsafe */
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add_wait_queue(&vc->paste_wait, &wait);
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while (sel_buffer && sel_buffer_lth > pasted) {
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set_current_state(TASK_INTERRUPTIBLE);
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if (test_bit(TTY_THROTTLED, &tty->flags)) {
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schedule();
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continue;
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}
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count = sel_buffer_lth - pasted;
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count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
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count);
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pasted += count;
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}
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remove_wait_queue(&vc->paste_wait, &wait);
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__set_current_state(TASK_RUNNING);
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tty_ldisc_deref(ld);
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return 0;
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}
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