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[英]segmentation faults when process launched in foreground is stopped with Ctrl+C
[英]who send SIGINT to foreground process when press ctrl+c, tty driver or shell
當我在登錄 shell 執行命令時按 ctrl+c 時,前台進程被殺死。
誰發出信號?
TTY 驅動程序是否直接將 SIGINT 發送到前台進程組?
或者 TTY 驅動程序是否將 SIGINT 發送到 shell,然后 shell 將信號重定向到前台進程組?
tty 驅動程序(特別是線路規則)將信號直接發送到前台進程組。 這是來自 Linux的代碼,您可以在其中看到它只是獲取前台組並發出信號:
/**
* [...]
* Called when a signal is being sent due to terminal input.
* [...]
*/
static void __isig(int sig, struct tty_struct *tty)
{
struct pid *tty_pgrp = tty_get_pgrp(tty);
if (tty_pgrp) {
kill_pgrp(tty_pgrp, sig, 1);
put_pid(tty_pgrp);
}
}
這是從同一文件中的輸入處理函數調用的,其中n_tty_receive_signal_char
距離調用__isig
僅幾步之__isig
:
/**
* [...]
* Process an individual character of input received from the driver.
* This is serialized with respect to itself by the rules for the
* driver above.
* [...]
*/
static int
n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
{
struct n_tty_data *ldata = tty->disc_data;
/* [...] */
if (L_ISIG(tty)) {
if (c == INTR_CHAR(tty)) {
n_tty_receive_signal_char(tty, SIGINT, c);
return 0;
} else if (c == QUIT_CHAR(tty)) {
n_tty_receive_signal_char(tty, SIGQUIT, c);
return 0;
} else if (c == SUSP_CHAR(tty)) {
n_tty_receive_signal_char(tty, SIGTSTP, c);
return 0;
}
}
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