Hi, Willy
Hi Zhangjin,
On Mon, Jul 10, 2023 at 01:06:00PM +0800, Zhangjin Wu wrote:
On Sat, Jul 08, 2023 at 02:38:57AM +0800, Zhangjin Wu wrote:
[...]
Now, we use "/tmp" directly in vfprintf, and we use argv0 for chmod_exe and chroot_exe, so, the only user of "/tmp" is vfprintf currently. In this case, it is a simple normal writable directory to allow create tmp files there, so, agree very much to only reserve the mkdir part:
/* create /tmp if not there. Silently fail otherwise */ mkdir("/tmp", 0755);OK, then I'll do that.
Thanks.
Another consideration before is whether it is required to be consistent with the normal Linux systems, let the "/tmp" directory mounted as tmpfs at most of the time,
That's not what I'm seeing on most of the systems I'm having access to, where /tmp is on a plain file system (either / or link to /var/tmp but always on disk, likely due to the huge size of the stuff stored there that is rarely used and that should not eat memory).
but "/tmp" means ramfs for CONFIG_TMPFS=n currently even mount it explicitly (ramfs is a fallback of tmpfs in such case), so, this assumption of "/tmp" means tmpfs is not true currently.
What I'm worried about is people in the future assume "/tmp" as tmpfs at the first glance and use the features only provided by TMPFS but not provided by RAMFS (I'm not sure which one they will use). so, I even tried to create a "/tmp/tmpfs" flag for TMPFS and "/tmp/ramfs" flag for RAMFS before, since there is no user to explicitly prefer TMPFS to RAMFS currently, at last, I removed these flags from the sent patchsets. Based on the same logic, The removal of tmpfs mount is of course ok.
Indeed, and also, please keep in mind what the purpose of nolibc-test is: make sure that the syscalls wrappers we write do work as expected, in part by allowing us to compare against another libc to figure whether it's the libc, the test or the kernel that causes any difference. The rest is purely out of scope. Thus it's not this test's business to verify that a tmpfs is indeed present after trying to mount it under /tmp, however it's this test business to make sure that options passed to mount() do work as expected, and that when a writable area is needed for a test, a working one is assigned. Thus for the specific case you mention, we don't care. And I'd go further, there can and should be reasonable prerequisites to run this test.
Ok.
So, Willy, is it ok for you to remove that mount line with corresponding update of the commit message (and the subject title), or require me to send a revision for this patch?
No worries, I've modified it accordingly with the following commit message, just let me know if you want to change anything:
commit 11fddb386bd663a554cc08c5950d9da2c87a7267 (HEAD) Author: Zhangjin Wu falcon@tinylab.org Date: Sat Jul 8 02:38:57 2023 +0800
selftests/nolibc: prepare /tmp for tests that need to writecreate a /tmp directory. If it succeeds, the directory is writable, which is normally the case when booted from an initramfs anyway. This will be used instead of procfs for some tests. Reviewed-by: Thomas Weißschuh linux@weissschuh.net Signed-off-by: Zhangjin Wu falcon@tinylab.org Link: https://lore.kernel.org/lkml/20230710050600.9697-1-falcon@tinylab.org/ [wt: removed the unneeded mount() call] Signed-off-by: Willy Tarreau w@1wt.eu
Perfectly, Thanks a lot.
Best regards, Zhangjin
Thanks! Willy