On 12/13/22 16:41, Hector Palacios wrote:
Hi Max,
On 12/13/22 13:24, Max van den Biggelaar wrote:
Hi,
I have a question regarding the U-Boot exit command. We are currently
using mainline U-Boot 2022.04 version to provide our embedded systems
with a bootloader image. To start our firmware via U-Boot environment,
we use a bootscript to start our firmware. However, when we tried to
exit a bootscript with the exit command, the bootscript was never exited.
After debugging to investigate the problem, we found this commit
(https://github.com/u-boot/u-boot/commit/8c4e3b79bd0bb76eea16869e9666e19047c0d005) in mainline U-Boot:
cmd: exit: Fix return value
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:
c26e454<https://github.com/u-boot/u-boot/commit/c26e454dfc6650428854fa2db3b1ed7f19e0ba0e>
Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Pantelis Antoniou <pantelis.anton...@konsulko.com>
Cc: Tom Rini <tr...@konsulko.com>
This commit does solve the problem of returning the correct value
given to the exit command, but this breaks the following source code
in common/cli_hush.c:
https://github.com/u-boot/u-boot/blob/master/common/cli_hush.c#L3207
In the previous versions of U-Boot, such as 2020.04, the exit command
returned -2, which was expected of the exit command API. However,
after the patch above to fix the return value, -2 was never returned
and the functionality to exit a bootscript or mainline U-Boot shell is
not supported anymore. Thus, by the patch above the return value is
fixed, but the functionality of the exit command is broken.
My question is if the functionality of this patch is fully
tested/qualified to push in mainline U-Boot source code? And if so, is
the functionality of the exit command also going to be fixed so that
in future U-Boot source code releases bootscripts can be exited with
this command?
I believe Marek's commit must be reverted as having 'exit' return a code
other than 0 (success) or 1 (error) was never part of U-Boot. I don't
know if reverting may break newer scripts, but now many scripts are
broken because 'exit' does not currently work.
Anyway, Marek wanted to give it a second thought. See
https://www.mail-archive.com/u-boot%40lists.denx.de/msg456830.html
Right, reverting the aforementioned commit breaks exit return value
handling. Special-casing 'exit' in shell with strcmp is not the right
approach, the exit behavior clearly needs closer look. I just haven't
had time to do that yet and reply to Hector.
