hush: fix ^C in INTERACTIVE, !EDITING config

function                                             old     new   delta
refill_HFILE_and_getc                                 88     170     +82
fgetc_interactive                                    226     250     +24
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 106/0)             Total: 106 bytes

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

1 files changed, 29 insertions, 6 deletions

diff --git a/shell/hush.c b/shell/hush.c
index e0b519217..d3444c556 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1649,6 +1649,26 @@ static int refill_HFILE_and_getc(HFILE *fp)
                 /* Already saw EOF */
                 return EOF;
         }
+#if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_EDITING
+        /* If user presses ^C, read() restarts after SIGINT (we use SA_RESTART).
+         * IOW: ^C will not immediately stop line input.
+         * But poll() is different: it does NOT restart after signals.
+         */
+        if (fp == G.HFILE_stdin) {
+                struct pollfd pfd[1];
+                pfd[0].fd = fp->fd;
+                pfd[0].events = POLLIN;
+                n = poll(pfd, 1, -1);
+                if (n < 0
+                 /*&& errno == EINTR - assumed true */
+                 && sigismember(&G.pending_set, SIGINT)
+                ) {
+                        return '\0';
+                }
+        }
+#else
+/* if FEATURE_EDITING=y, we do not use this routine for interactive input */
+#endif
         /* Try to buffer more input */
         n = safe_read(fp->fd, fp->buf, sizeof(fp->buf));
         if (n < 0) {
@@ -2090,7 +2110,6 @@ static void hush_exit(int exitcode)
 #endif
 }
 
-
 //TODO: return a mask of ALL handled sigs?
 static int check_and_run_traps(void)
 {
@@ -2665,19 +2684,23 @@ static int get_user_input(struct in_str *i)
                          */
                         check_and_run_traps();
                         fputs(prompt_str, stdout);
+                        fflush_all();
                 }
-                fflush_all();
-//FIXME: here ^C or SIGINT will have effect only after <Enter>
                 r = hfgetc(i->file);
                 /* In !ENABLE_FEATURE_EDITING we don't use read_line_input,
                  * no ^C masking happens during fgetc, no special code for ^C:
                  * it generates SIGINT as usual.
                  */
                 check_and_run_traps();
-                if (G.flag_SIGINT)
-                        G.last_exitcode = 128 | SIGINT;
-                if (r != '\0')
+                if (r != '\0' && !G.flag_SIGINT)
                         break;
+                if (G.flag_SIGINT) {
+                        /* ^C or SIGINT: repeat */
+                        /* bash prints ^C even on real SIGINT (non-kbd generated) */
+                        /* kernel prints "^C" itself, just print newline: */
+                        write(STDOUT_FILENO, "\n", 1);
+                        G.last_exitcode = 128 | SIGINT;
+                }
         }
         return r;
 # endif