[v2 PATCH] eval: Only restore exit status on exit/return

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Sat, Dec 01, 2018 at 04:45:39PM +0800, Herbert Xu wrote:
> 
> Hmm, I think this breaks the following case which used to work:
> 
> 	dash -c 'trap "(:; exit) && echo BUG" EXIT; false'
> 
> I know this makes no sense but almost every other shell does it
> this way.

Here is a new patch that fixes the reported issue for both signal
traps and the EXIT trap.

---8<---
We unconditionally restore the saved status in exitreset, which
is incorrect as we only want to do it for exitcmd and returncmd.
This patch fixes the problem by introducing EXEND.

Reported-by: Martijn Dekker <martijn@xxxxxxxx>
Fixes: da30b4b78769 ("[BUILTIN] Exit without arguments in a trap...")
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/src/error.h b/src/error.h
index 9630b56..94e30a2 100644
--- a/src/error.h
+++ b/src/error.h
@@ -66,7 +66,8 @@ extern int exception;
 /* exceptions */
 #define EXINT 0		/* SIGINT received */
 #define EXERROR 1	/* a generic error */
-#define EXEXIT 4	/* exit the shell */
+#define EXEND 3		/* exit the shell */
+#define EXEXIT 4	/* exit the shell via exitcmd */
 
 
 /*
diff --git a/src/eval.c b/src/eval.c
index 546ee1b..3cea2a3 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -114,12 +114,13 @@ STATIC const struct builtincmd bltin = {
 INCLUDE "eval.h"
 
 EXITRESET {
-	evalskip = 0;
-	loopnest = 0;
 	if (savestatus >= 0) {
-		exitstatus = savestatus;
+		if (exception == EXEXIT || evalskip == SKIPFUNCDEF)
+			exitstatus = savestatus;
 		savestatus = -1;
 	}
+	evalskip = 0;
+	loopnest = 0;
 }
 #endif
 
@@ -314,7 +315,7 @@ out:
 
 	if (flags & EV_EXIT) {
 exexit:
-		exraise(EXEXIT);
+		exraise(EXEND);
 	}
 
 	return exitstatus;
diff --git a/src/exec.c b/src/exec.c
index 9d0215a..87354d4 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -143,7 +143,7 @@ shellexec(char **argv, const char *path, int idx)
 	exitstatus = exerrno;
 	TRACE(("shellexec failed for %s, errno %d, suppressint %d\n",
 		argv[0], e, suppressint ));
-	exerror(EXEXIT, "%s: %s", argv[0], errmsg(e, E_EXEC));
+	exerror(EXEND, "%s: %s", argv[0], errmsg(e, E_EXEC));
 	/* NOTREACHED */
 }
 
diff --git a/src/main.c b/src/main.c
index 6d53e00..6b3a090 100644
--- a/src/main.c
+++ b/src/main.c
@@ -111,7 +111,7 @@ main(int argc, char **argv)
 		e = exception;
 
 		s = state;
-		if (e == EXEXIT || s == 0 || iflag == 0 || shlvl)
+		if (e == EXEND || e == EXEXIT || s == 0 || iflag == 0 || shlvl)
 			exitshell();
 
 		reset();
diff --git a/src/trap.c b/src/trap.c
index ab0ecd4..64917fc 100644
--- a/src/trap.c
+++ b/src/trap.c
@@ -397,8 +397,10 @@ exitshell(void)
 		trap[0] = NULL;
 		evalskip = 0;
 		evalstring(p, 0);
+		evalskip = SKIPFUNCDEF;
 	}
 out:
+	exitreset();
 	/*
 	 * Disable job control so that whoever had the foreground before we
 	 * started can get it back.
@@ -406,7 +408,7 @@ out:
 	if (likely(!setjmp(loc.loc)))
 		setjobctl(0);
 	flushall();
-	_exit(savestatus);
+	_exit(exitstatus);
 	/* NOTREACHED */
 }
 

-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt