[PATCH v2] tools/nolibc: make time_t robust if __kernel_old_time_t is missing in host headers

[PATCH v2] tools/nolibc: make time_t robust if __kernel_old_time_t is missing in host headers

[Zhouyi Zhou]

Commit d5094bcb5bfd ("tools/nolibc: define time_t in terms of
__kernel_old_time_t") made nolibc use the kernel's time type so that
`time_t` matches `timespec::tv_sec` on all ABIs (notably x32).

But since __kernel_old_time_t
is fairly new, notably from 2020 in commit 94c467ddb273 ("y2038: add
__kernel_old_timespec and __kernel_old_time_t"), nolibc builds that
rely on host headers may fail.

Switch to __kernel_time_t, which is the same as
__kernel_old_time_t and has existed for longer.    

Tested in PPC VM of Open Source Lab of Oregon State University
(./tools/testing/selftests/rcutorture/bin/mkinitrd.sh)

Fixes: d5094bcb5bfd ("tools/nolibc: define time_t in terms of __kernel_old_time_t")
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>                     
---
 tools/include/nolibc/std.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/include/nolibc/std.h b/tools/include/nolibc/std.h
index ba950f0e7338..3940778822f4 100644
--- a/tools/include/nolibc/std.h
+++ b/tools/include/nolibc/std.h
@@ -29,6 +29,6 @@ typedef unsigned long       nlink_t;
 typedef   signed long         off_t;
 typedef   signed long     blksize_t;
 typedef   signed long      blkcnt_t;
-typedef __kernel_old_time_t  time_t;
+typedef __kernel_time_t  time_t;
 
 #endif /* _NOLIBC_STD_H */
-- 
2.25.1

Re: [PATCH v2] tools/nolibc: make time_t robust if __kernel_old_time_t is missing in host headers

[Thomas Weißschuh]

On 2025-09-19 01:46:43+0000, Zhouyi Zhou wrote:
> Commit d5094bcb5bfd ("tools/nolibc: define time_t in terms of
> __kernel_old_time_t") made nolibc use the kernel's time type so that
> `time_t` matches `timespec::tv_sec` on all ABIs (notably x32).
> 
> But since __kernel_old_time_t
> is fairly new, notably from 2020 in commit 94c467ddb273 ("y2038: add
> __kernel_old_timespec and __kernel_old_time_t"), nolibc builds that
> rely on host headers may fail.
> 
> Switch to __kernel_time_t, which is the same as
> __kernel_old_time_t and has existed for longer.    
> 
> Tested in PPC VM of Open Source Lab of Oregon State University
> (./tools/testing/selftests/rcutorture/bin/mkinitrd.sh)
> 
> Fixes: d5094bcb5bfd ("tools/nolibc: define time_t in terms of __kernel_old_time_t")
> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>                     

Thanks! Although it is fairly late in the developmment cycle I have
applied it to nolibc-next for 6.18.

(...)