ash: ^C with SIG_INGed SIGINT should not exit the shell

function                                             old     new   delta
__pgetc                                              501     522     +21

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 15 insertions, 2 deletions

diff --git a/loginutils/login.c b/loginutils/login.c
index 569053c12..cac4349b2 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -608,7 +608,9 @@ int login_main(int argc UNUSED_PARAM, char **argv)
          * But without this, bash 3.0 will not enable ctrl-c either.
          * Maybe bash is buggy?
          * Need to find out what standards say about /bin/login -
-         * should we leave SIGINT etc enabled or disabled? */
+         * should we leave SIGINT etc enabled or disabled?
+         * Also note: sulogin does not do it! Why?
+         */
         signal(SIGINT, SIG_DFL);
 
         /* Exec login shell with no additional parameters */
diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
index 5f1c1178f..2f87c77c0 100644
--- a/loginutils/sulogin.c
+++ b/loginutils/sulogin.c
@@ -111,6 +111,11 @@ int sulogin_main(int argc UNUSED_PARAM, char **argv)
                 }
         }
 
+        /*
+         * Note: login does this (should we do it too?):
+         */
+        /*signal(SIGINT, SIG_DFL);*/
+
         /* Exec login shell with no additional parameters. Never returns. */
         exec_login_shell(shell);
 }
diff --git a/shell/ash.c b/shell/ash.c
index 4c5dd1298..12b2db3a9 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -10784,18 +10784,24 @@ preadfd(void)
                 line_input_state->path_lookup = pathval();
 # endif
                 reinit_unicode_for_ash();
+ again:
                 nr = read_line_input(line_input_state, cmdedit_prompt, buf, IBUFSIZ);
                 if (nr == 0) {
                         /* ^C pressed, "convert" to SIGINT */
                         write(STDOUT_FILENO, "^C", 2);
                         raise(SIGINT);
+                        /* raise(SIGINT) did not work! (e.g. if SIGINT
+                         * is SIG_INGed on startup, it stays SIG_IGNed)
+                         */
                         if (trap[SIGINT]) {
                                 buf[0] = '\n';
                                 buf[1] = '\0';
                                 return 1;
                         }
                         exitstatus = 128 + SIGINT;
-                        return -1;
+                        /* bash behavior on ^C + ignored SIGINT: */
+                        write(STDOUT_FILENO, "\n", 1);
+                        goto again;
                 }
                 if (nr < 0) {
                         if (errno == 0) {