hush: do not allow sh -c '{ echo boo }'

[oweals/busybox.git] / shell / ash.c

diff --git a/shell/ash.c b/shell/ash.c
index ecd2146e462592329676c303def614fb01f4b90c..87f2127a1f491d81da431e2692a2bbe8cb94a0dd 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -32,6 +32,7 @@
 #define DEBUG_TIME 0
 #define DEBUG_PID 1
 #define DEBUG_SIG 1
+#define DEBUG_INTONOFF 0
 
 #define PROFILE 0
 
@@ -442,10 +443,18 @@ static void exitshell(void) NORETURN;
  * much more efficient and portable.  (But hacking the kernel is so much
  * more fun than worrying about efficiency and portability. :-))
  */
-#define INT_OFF do { \
+#if DEBUG_INTONOFF
+# define INT_OFF do { \
+       TRACE(("%s:%d INT_OFF(%d)\n", __func__, __LINE__, suppress_int)); \
        suppress_int++; \
        barrier(); \
 } while (0)
+#else
+# define INT_OFF do { \
+       suppress_int++; \
+       barrier(); \
+} while (0)
+#endif
 
 /*
  * Called to raise an exception.  Since C doesn't include exceptions, we
@@ -513,7 +522,14 @@ int_on(void)
                raise_interrupt();
        }
 }
-#define INT_ON int_on()
+#if DEBUG_INTONOFF
+# define INT_ON do { \
+       TRACE(("%s:%d INT_ON(%d)\n", __func__, __LINE__, suppress_int-1)); \
+       int_on(); \
+} while (0)
+#else
+# define INT_ON int_on()
+#endif
 static IF_ASH_OPTIMIZE_FOR_SIZE(inline) void
 force_int_on(void)
 {
@@ -3933,6 +3949,8 @@ wait_block_or_sig(int *status)
        int pid;
 
        do {
+               sigset_t mask;
+
                /* Poll all children for changes in their state */
                got_sigchld = 0;
                /* if job control is active, accept stopped processes too */
@@ -3941,14 +3959,13 @@ wait_block_or_sig(int *status)
                        break; /* Error (e.g. EINTR, ECHILD) or pid */
 
                /* Children exist, but none are ready. Sleep until interesting signal */
-#if 0 /* dash does this */
-               sigset_t mask;
+#if 1
                sigfillset(&mask);
                sigprocmask(SIG_SETMASK, &mask, &mask);
                while (!got_sigchld && !pending_sig)
                        sigsuspend(&mask);
                sigprocmask(SIG_SETMASK, &mask, NULL);
-#else
+#else /* unsafe: a signal can set pending_sig after check, but before pause() */
                while (!got_sigchld && !pending_sig)
                        pause();
 #endif
@@ -3987,9 +4004,9 @@ dowait(int block, struct job *job)
         * either enter a sleeping waitpid() (BUG), or need to busy-loop.
         *
         * Because of this, we run inside INT_OFF, but use a special routine
-        * which combines waitpid() and pause().
+        * which combines waitpid() and sigsuspend().
         * This is the reason why we need to have a handler for SIGCHLD:
-        * SIG_DFL handler does not wake pause().
+        * SIG_DFL handler does not wake sigsuspend().
         */
        INT_OFF;
        if (block == DOWAIT_BLOCK_OR_SIG) {
@@ -9100,7 +9117,7 @@ mklocal(char *name)
                        /* else:
                         * it's a duplicate "local VAR" declaration, do nothing
                         */
-                       return;
+                       goto ret;
                }
                lvp = lvp->next;
        }
@@ -9139,6 +9156,7 @@ mklocal(char *name)
        lvp->vp = vp;
        lvp->next = localvars;
        localvars = lvp;
+ ret:
        INT_ON;
 }