![Peter Hurley](/assets/img/avatar_default.png)
tty file_operations (read/write/ioctl) wait for the ldisc reference indefinitely (until ldisc lifetime events, such as hangup or TIOCSETD, finish). Since hangup now destroys the ldisc and does not instance another copy, file_operations must now be prepared to receive a NULL ldisc reference from tty_ldisc_ref_wait(): CPU 0 CPU 1 ----- ----- (*f_op->read)() => tty_read() __tty_hangup() ... f_op = &hung_up_tty_fops; ... tty_ldisc_hangup() tty_ldisc_lock() tty_ldisc_kill() tty->ldisc = NULL tty_ldisc_unlock() ld = tty_ldisc_ref_wait() /* ld == NULL */ Instead, the action taken now is to return the same value as if the tty had been hungup a moment earlier: CPU 0 CPU 1 ----- ----- __tty_hangup() ... f_op = &hung_up_tty_fops; (*f_op->read)() => hung_up_tty_read() return 0; ... tty_ldisc_hangup() tty_ldisc_lock() tty_ldisc_kill() tty->ldisc = NULL tty_ldisc_unlock() Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
374 lines
9.3 KiB
C
374 lines
9.3 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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#include <linux/tty_flip.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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if (!ld)
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return -EIO; /* ldisc was hung up */
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tty_buffer_lock_exclusive(&vc->port);
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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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__set_current_state(TASK_RUNNING);
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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_buffer_unlock_exclusive(&vc->port);
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tty_ldisc_deref(ld);
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return 0;
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}
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