ash: INT_OFF/INT_ON around run_nofork_applet()

function                                             old     new   delta
evalcommand                                         1441    1447      +6

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

1 files changed, 19 insertions, 3 deletions

diff --git a/shell/ash.c b/shell/ash.c
index ca9926b54..2afa5e83d 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9919,10 +9919,26 @@ evalcommand(union node *cmd, int flags)
                 int applet_no = (- cmdentry.u.index - 2);
                 if (applet_no >= 0 && APPLET_IS_NOFORK(applet_no)) {
                         listsetvar(varlist.list, VEXPORT|VSTACK);
-                        /* run <applet>_main() */
-//FIXME: do we need INT_OFF / INT_ON here?
-//wouldn't open files and allocations leak on ^C otherwise?
+                        /*
+                         * Run <applet>_main().
+                         * Signals (^C) can't interrupt here.
+                         * Otherwise we can mangle stdio or malloc internal state.
+                         * This makes applets which can run for a long time
+                         * and/or wait for user input ineligible for NOFORK:
+                         * for example, "yes" or "rm" (rm -i waits for input).
+                         */
+                        INT_OFF;
                         status = run_nofork_applet(applet_no, argv);
+                        /*
+                         * Try enabling NOFORK for "yes" applet.
+                         * ^C _will_ stop it (write returns EINTR),
+                         * but this causes stdout FILE to be stuck
+                         * and needing clearerr(). What if other applets
+                         * also can get EINTRs? Do we need to switch
+                         * our signals to SA_RESTART?
+                         */
+                        /*clearerr(stdout);*/
+                        INT_ON;
                         break;
                 }
 #endif