[PATCH] [RFC] cmd: exit: Fix return value

[Marek Vasut]

In case exit is called in a script without parameter, the command
returns -2 ; in case exit is called with a numerical parameter,
the command returns -2 and lower. This leads to the following problem:
=> setenv foo 'echo bar ; exit 1' ; run foo ; echo $?
bar
0
=> setenv foo 'echo bar ; exit 0' ; run foo ; echo $?
bar
0
=> setenv foo 'echo bar ; exit -2' ; run foo ; echo $?
bar
0
That is, no matter what the 'exit' command argument is, the return
value is always 0 and so it is not possible to use script return
value in subsequent tests.

Fix this and simplify the exit command such that if exit is called with
no argument, the command returns 0, just like 'true' in cmd/test.c. In
case the command is called with any argument that is positive integer,
the argument is set as return value.
=> setenv foo 'echo bar ; exit 1' ; run foo ; echo $?
bar
1
=> setenv foo 'echo bar ; exit 0' ; run foo ; echo $?
bar
0
=> setenv foo 'echo bar ; exit -2' ; run foo ; echo $?
bar
0

Note that this does change ABI established in 2004 , although it is
unclear whether that ABI was originally OK or not.

Fixes: c26e454dfc6
Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Pantelis Antoniou <pantelis.antoniou at konsulko.com>
Cc: Tom Rini <trini at konsulko.com>
---
 cmd/exit.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/cmd/exit.c b/cmd/exit.c
index f40d0686e1e..af9ff56180c 100644
--- a/cmd/exit.c
+++ b/cmd/exit.c
@@ -9,13 +9,10 @@
 
 static int do_exit(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
-	int r;
-
-	r = 0;
 	if (argc > 1)
-		r = simple_strtoul(argv[1], NULL, 10);
+		return simple_strtoul(argv[1], NULL, 10);
 
-	return -r - 2;
+	return 0;
 }
 
 U_BOOT_CMD(
-- 
2.30.2