ash,hush: fix handling of SIGINT while waiting for interactive input
function old new delta lineedit_read_key 160 237 +77 __pgetc 522 589 +67 fgetc_interactive 244 309 +65 safe_read_key - 39 +39 read_key 588 607 +19 record_pending_signo 23 32 +9 signal_handler 75 81 +6 .rodata 104312 104309 -3 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 6/1 up/down: 282/-3) Total: 279 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
39
shell/ash.c
39
shell/ash.c
@ -3679,7 +3679,9 @@ signal_handler(int signo)
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if (!trap[SIGCHLD])
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return;
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}
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#if ENABLE_FEATURE_EDITING
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bb_got_signal = signo; /* for read_line_input: "we got a signal" */
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#endif
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gotsig[signo - 1] = 1;
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pending_sig = signo;
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@ -10784,33 +10786,52 @@ preadfd(void)
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# endif
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reinit_unicode_for_ash();
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again:
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//BUG: not in INT_OFF/INT_ON section - SIGINT et al would longjmp out of read_line_input()!
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//This would cause a memory leak in interactive shell
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//(repeated internal allocations in read_line_input):
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// (while kill -INT $$; do :; done) &
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/* For shell, LI_INTERRUPTIBLE is set:
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* read_line_input will abort on either
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* getting EINTR in poll(), or if it sees bb_got_signal != 0
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* (IOW: if signal arrives before poll() is reached).
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* Interactive testcases:
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* (while kill -INT $$; do sleep 1; done) &
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* #^^^ prints ^C, prints prompt, repeats
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* trap 'echo I' int; (while kill -INT $$; do sleep 1; done) &
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* #^^^ prints ^C, prints "I", prints prompt, repeats
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* trap 'echo T' term; (while kill $$; do sleep 1; done) &
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* #^^^ prints "T", prints prompt, repeats
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* #(bash 5.0.17 exits after first "T", looks like a bug)
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*/
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bb_got_signal = 0;
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INT_OFF; /* no longjmp'ing out of read_line_input please */
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nr = read_line_input(line_input_state, cmdedit_prompt, buf, IBUFSIZ);
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if (bb_got_signal == SIGINT)
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write(STDOUT_FILENO, "^C\n", 3);
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INT_ON; /* here non-blocked SIGINT will longjmp */
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if (nr == 0) {
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/* ^C pressed, "convert" to SIGINT */
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write(STDOUT_FILENO, "^C", 2);
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raise(SIGINT);
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write(STDOUT_FILENO, "^C\n", 3);
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raise(SIGINT); /* here non-blocked SIGINT will longjmp */
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/* raise(SIGINT) did not work! (e.g. if SIGINT
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* is SIG_IGNed on startup, it stays SIG_IGNed)
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*/
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if (trap[SIGINT]) {
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empty_line_input:
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buf[0] = '\n';
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buf[1] = '\0';
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return 1;
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}
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exitstatus = 128 + SIGINT;
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/* bash behavior on ^C + ignored SIGINT: */
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write(STDOUT_FILENO, "\n", 1);
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goto again;
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}
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if (nr < 0) {
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if (errno == 0) {
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/* Ctrl+D pressed */
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/* ^D pressed */
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nr = 0;
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}
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else if (errno == EINTR) { /* got signal? */
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if (bb_got_signal != SIGINT)
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write(STDOUT_FILENO, "\n", 1);
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goto empty_line_input;
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}
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# if ENABLE_ASH_IDLE_TIMEOUT
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else if (errno == EAGAIN && timeout > 0) {
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puts("\007timed out waiting for input: auto-logout");
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67
shell/hush.c
67
shell/hush.c
@ -918,6 +918,7 @@ struct globals {
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#if ENABLE_HUSH_INTERACTIVE
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smallint promptmode; /* 0: PS1, 1: PS2 */
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#endif
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/* set by signal handler if SIGINT is received _and_ its trap is not set */
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smallint flag_SIGINT;
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#if ENABLE_HUSH_LOOPS
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smallint flag_break_continue;
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@ -1944,6 +1945,9 @@ enum {
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static void record_pending_signo(int sig)
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{
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sigaddset(&G.pending_set, sig);
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#if ENABLE_FEATURE_EDITING
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bb_got_signal = sig; /* for read_line_input: "we got a signal" */
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#endif
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#if ENABLE_HUSH_FAST
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if (sig == SIGCHLD) {
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G.count_SIGCHLD++;
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@ -2652,30 +2656,53 @@ static int get_user_input(struct in_str *i)
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for (;;) {
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reinit_unicode_for_hush();
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G.flag_SIGINT = 0;
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/* buglet: SIGINT will not make new prompt to appear _at once_,
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* only after <Enter>. (^C works immediately) */
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r = read_line_input(G.line_input_state, prompt_str,
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bb_got_signal = 0;
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if (!sigisemptyset(&G.pending_set)) {
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/* Whoops, already got a signal, do not call read_line_input */
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bb_got_signal = r = -1;
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} else {
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/* For shell, LI_INTERRUPTIBLE is set:
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* read_line_input will abort on either
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* getting EINTR in poll(), or if it sees bb_got_signal != 0
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* (IOW: if signal arrives before poll() is reached).
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* Interactive testcases:
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* (while kill -INT $$; do sleep 1; done) &
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* #^^^ prints ^C, prints prompt, repeats
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* trap 'echo I' int; (while kill -INT $$; do sleep 1; done) &
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* #^^^ prints ^C, prints "I", prints prompt, repeats
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* trap 'echo T' term; (while kill $$; do sleep 1; done) &
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* #^^^ prints "T", prints prompt, repeats
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* #(bash 5.0.17 exits after first "T", looks like a bug)
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*/
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r = read_line_input(G.line_input_state, prompt_str,
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G.user_input_buf, CONFIG_FEATURE_EDITING_MAX_LEN-1
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);
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/* read_line_input intercepts ^C, "convert" it to SIGINT */
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if (r == 0) {
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raise(SIGINT);
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);
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/* read_line_input intercepts ^C, "convert" it to SIGINT */
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if (r == 0)
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raise(SIGINT);
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}
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/* bash prints ^C (before running a trap, if any)
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* both on keyboard ^C and on real SIGINT (non-kbd generated).
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*/
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if (sigismember(&G.pending_set, SIGINT)) {
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write(STDOUT_FILENO, "^C\n", 3);
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G.last_exitcode = 128 | SIGINT;
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}
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check_and_run_traps();
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if (r != 0 && !G.flag_SIGINT)
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if (r == 0) /* keyboard ^C? */
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continue; /* go back, read another input line */
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if (r > 0) /* normal input? (no ^C, no ^D, no signals) */
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break;
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/* ^C or SIGINT: repeat */
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/* bash prints ^C even on real SIGINT (non-kbd generated) */
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write(STDOUT_FILENO, "^C\n", 3);
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G.last_exitcode = 128 | SIGINT;
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}
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if (r < 0) {
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/* EOF/error detected */
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/* ^D on interactive input goes to next line before exiting: */
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write(STDOUT_FILENO, "\n", 1);
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i->p = NULL;
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i->peek_buf[0] = r = EOF;
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return r;
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if (!bb_got_signal) {
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/* r < 0: ^D/EOF/error detected (but not signal) */
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/* ^D on interactive input goes to next line before exiting: */
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write(STDOUT_FILENO, "\n", 1);
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i->p = NULL;
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i->peek_buf[0] = r = EOF;
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return r;
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}
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/* it was a signal: go back, read another input line */
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}
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i->p = G.user_input_buf;
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return (unsigned char)*i->p++;
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