ash: [BUILTIN] Exit without arguments in a trap should use status outside traps

Upstream commit:

    Date:   Mon Oct 6 10:39:47 2014 +0800
    [BUILTIN] Exit without arguments in a trap should use status outside traps

    POSIX now requires that exit without arguments in a trap should
    return the last command status prior to executing traps.  This
    patch implements this behaviour.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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

3 files changed, 38 insertions, 13 deletions

diff --git a/shell/ash.c b/shell/ash.c
index a300061a2..270a338d9 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -384,6 +384,7 @@ struct globals_misc {
         uint8_t exitstatus;     /* exit status of last command */
         uint8_t back_exitstatus;/* exit status of backquoted command */
         smallint job_warning;   /* user was warned about stopped jobs (can be 2, 1 or 0). */
+        int savestatus;         /* exit status of last command outside traps */
         int rootpid;            /* pid of main shell */
         /* shell level: 0 for the main shell, 1 for its children, and so on */
         int shlvl;
@@ -466,6 +467,7 @@ extern struct globals_misc *BB_GLOBAL_CONST ash_ptr_to_globals_misc;
 #define exitstatus        (G_misc.exitstatus )
 #define back_exitstatus   (G_misc.back_exitstatus )
 #define job_warning       (G_misc.job_warning)
+#define savestatus  (G_misc.savestatus )
 #define rootpid     (G_misc.rootpid    )
 #define shlvl       (G_misc.shlvl      )
 #define errlinno    (G_misc.errlinno   )
@@ -491,6 +493,7 @@ extern struct globals_misc *BB_GLOBAL_CONST ash_ptr_to_globals_misc;
 #define INIT_G_misc() do { \
         (*(struct globals_misc**)not_const_pp(&ash_ptr_to_globals_misc)) = xzalloc(sizeof(G_misc)); \
         barrier(); \
+        savestatus = -1; \
         curdir = nullstr; \
         physdir = nullstr; \
         trap_ptr = trap; \
@@ -9055,12 +9058,17 @@ dotrap(void)
 {
         uint8_t *g;
         int sig;
-        uint8_t last_status;
+        int status, last_status;
 
         if (!pending_sig)
                 return;
 
-        last_status = exitstatus;
+        status = savestatus;
+        last_status = status;
+        if (status < 0) {
+                status = exitstatus;
+                savestatus = status;
+        }
         pending_sig = 0;
         barrier();
 
@@ -9087,8 +9095,10 @@ dotrap(void)
                 if (!p)
                         continue;
                 evalstring(p, 0);
+                exitstatus = status;
         }
-        exitstatus = last_status;
+
+        savestatus = last_status;
         TRACE(("dotrap returns\n"));
 }
 
@@ -13416,8 +13426,15 @@ exitcmd(int argc UNUSED_PARAM, char **argv)
 {
         if (stoppedjobs())
                 return 0;
-        if (argv[1])
-                exitstatus = number(argv[1]);
+
+        if (argv[1]) {
+                int status = number(argv[1]);
+
+                exitstatus = status;
+                if (savestatus >= 0)
+                        savestatus = status;
+        }
+
         raise_exception(EXEXIT);
         /* NOTREACHED */
 }
@@ -14077,19 +14094,15 @@ exitshell(void)
 {
         struct jmploc loc;
         char *p;
-        int status;
 
 #if ENABLE_FEATURE_EDITING_SAVE_ON_EXIT
         if (line_input_state)
                 save_history(line_input_state);
 #endif
-        status = exitstatus;
-        TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
-        if (setjmp(loc.loc)) {
-                if (exception_type == EXEXIT)
-                        status = exitstatus;
+        savestatus = exitstatus;
+        TRACE(("pid %d, exitshell(%d)\n", getpid(), savestatus));
+        if (setjmp(loc.loc))
                 goto out;
-        }
         exception_handler = &loc;
         p = trap[0];
         if (p) {
@@ -14104,7 +14117,7 @@ exitshell(void)
          */
         setjobctl(0);
         flush_stdout_stderr();
-        _exit(status);
+        _exit(savestatus);
         /* NOTREACHED */
 }
 
@@ -14280,6 +14293,10 @@ reset(void)
         /* from eval.c: */
         evalskip = 0;
         loopnest = 0;
+        if (savestatus >= 0) {
+                exitstatus = savestatus;
+                savestatus = -1;
+        }
 
         /* from expand.c: */
         ifsfree();
diff --git a/shell/ash_test/ash-misc/exitcode_trap1.right b/shell/ash_test/ash-misc/exitcode_trap1.right
new file mode 100644
index 000000000..5f76f68da
--- /dev/null
+++ b/shell/ash_test/ash-misc/exitcode_trap1.right
@@ -0,0 +1,2 @@
+Trapped
+One:1
diff --git a/shell/ash_test/ash-misc/exitcode_trap1.tests b/shell/ash_test/ash-misc/exitcode_trap1.tests
new file mode 100755
index 000000000..c35b6b391
--- /dev/null
+++ b/shell/ash_test/ash-misc/exitcode_trap1.tests
@@ -0,0 +1,6 @@
+# "exit" in trap should not use last command's exitcode,
+# but exitcode on entering the trap.
+(trap "echo Trapped; exit" EXIT
+ (exit 1)
+)
+echo One:$?