Hi, Thomas
On 2023-07-10 17:26:43+0800, Zhangjin Wu wrote:
On 2023-07-08 23:29:58+0800, Zhangjin Wu wrote:
[...]
It also seems like a good opportunity to add some tests for argv/environment variable passing.
Yes, and even further, we can do more on auxv, just like musl does in src/env/__libc_start_main.c, not that urgent currently:
With tests I mean nolibc-test.c to make sure we don't introduce any regressions. Only some tiny testcases to validate that argv and environ are picked up correctly by the startup code on all arches.
Thomas, seems we already have some testcases for argv, environ and auxv currently:
run_syscall: chmod_argv0 <-- argv[0] chdir_root <-- chdir(getenv("PWD")) getpagesize <-- getauxval(AT_PAGESZ) run_stdlib : getenv_TERM <-- getenv
[...]
Ok, welcome to discuss more in this thread:
https://lore.kernel.org/lkml/20230710072340.10798-1-falcon@tinylab.org/and let's choose a better method as possible as we can, Just replied Willy to explain more.
Will do.
Signed-off-by: Zhangjin Wu falcon@tinylab.org
tools/include/nolibc/crt.h | 44 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+)
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h index 221b7c5346ca..b269294e9664 100644 --- a/tools/include/nolibc/crt.h +++ b/tools/include/nolibc/crt.h @@ -13,4 +13,48 @@ char **environ __attribute__((weak));
The old code seems to avoid putting "environ" into the global symbol namespace. Could this declaration be moved into the function like in getenv()?
ok, do you mean just move it to stdlib.h like this? I moved _auxv (used by getauxv()) to stdlib.h too:
Nevermind, I got confused by the in-function declaration of "extern char **environ" inside "getenv()". Actually this in-function declaration doesn't do anything and can be dropped.
Yes. for nolibc application is in one-file style, let's remove it.
[...]
This will lead to conflicting declarations if the users use a different signature. I'm not (yet?) sure how to work around this.
Ah yes, I forgot this critical case, people may use something like:
int main(void) int main(int argc, char *argv[])[..]
I thought about this general problem and it turns out that there is nothing that any libc can do to distinguish these special cases. So it has to be handled in the compiler and we do not have to care.
Ok.
Thanks, Zhangjin
Thomas