sh: Do not run callers' exception handlers in subshells.

Reset the exception handler in the child to main's.

This avoids inappropriate double cleanups or shell duplication when the
exception is caught, such as 'fc' and future 'command eval' and 'command .'.

3 files changed, 5 insertions, 3 deletions

diff --git a/bin/sh/jobs.c b/bin/sh/jobs.c
index 1ebf722..95ec6e2 100644
--- a/bin/sh/jobs.c
+++ b/bin/sh/jobs.c
@@ -757,6 +757,7 @@ forkshell(struct job *jp, union node *n, int mode)
 		TRACE(("Child shell %d\n", (int)getpid()));
 		wasroot = rootshell;
 		rootshell = 0;
+		handler = &main_handler;
 		closescript();
 		INTON;
 		clear_traps();
diff --git a/bin/sh/main.c b/bin/sh/main.c
index 547aad9..c21e8df 100644
--- a/bin/sh/main.c
+++ b/bin/sh/main.c
@@ -75,6 +75,7 @@ __FBSDID("$FreeBSD$");
 
 int rootpid;
 int rootshell;
+struct jmploc main_handler;
 
 STATIC void read_profile(char *);
 STATIC char *find_dot_file(char *);
@@ -90,14 +91,13 @@ STATIC char *find_dot_file(char *);
 int
 main(int argc, char *argv[])
 {
-	struct jmploc jmploc;
 	struct stackmark smark;
 	volatile int state;
 	char *shinit;
 
 	(void) setlocale(LC_ALL, "");
 	state = 0;
-	if (setjmp(jmploc.loc)) {
+	if (setjmp(main_handler.loc)) {
 		/*
 		 * When a shell procedure is executed, we raise the
 		 * exception EXSHELLPROC to clean up before executing
@@ -143,7 +143,7 @@ main(int argc, char *argv[])
 		else
 			goto state4;
 	}
-	handler = &jmploc;
+	handler = &main_handler;
 #ifdef DEBUG
 	opentrace();
 	trputs("Shell args:  ");  trargs(argv);
diff --git a/bin/sh/main.h b/bin/sh/main.h
index b6dadc3..c5e8bfd3 100644
--- a/bin/sh/main.h
+++ b/bin/sh/main.h
@@ -35,6 +35,7 @@
 
 extern int rootpid;	/* pid of main shell */
 extern int rootshell;	/* true if we aren't a child of the main shell */
+extern struct jmploc main_handler;	/* top level exception handler */
 
 void readcmdfile(const char *);
 void cmdloop(int);