On 2/6/21 10:54 AM, Michael Kerrisk (man-pages) wrote:
> Hi Alex,
>
> Can we please begin every commit message with some English sentences :-).
Sure! Thanks for the reminder! :-)
>
> I'm a little hesitant about the proposed change. execve() has a
> similar prototype in the kernel, but the glibc wrapper is just:
>
> extern int execve (const char *__path, char *const __argv[],
> char *const __envp[]) ;
I guess that was the reason to write it like that.
>
> I expect that one day when execveat() is added to glibc, it will be
> the same. What do you think?
execveat() was added 6 years ago to the kernel (kernel commit
51f39a1f0cea1cacf8c787f652f26dfee9611874) and there's still no wrapper.
It's not like epoll_pwait2() that isn't yet in a stable release. I'd
document the actual prototype, maybe open a bug in glibc to request a
wrapper, and if some day glibc adds that wrapper, I'd just revert the
commit. Wouldn't you?
Thanks,
Alex
>
> Thanks,
>
> Michael
>
> On Wed, 3 Feb 2021 at 19:46, Alejandro Colomar <alx.manpages@xxxxxxxxx> wrote:
>>
>> .../linux$ grep_syscall execveat
>> fs/exec.c:2062:
>> SYSCALL_DEFINE5(execveat,
>> int, fd, const char __user *, filename,
>> const char __user *const __user *, argv,
>> const char __user *const __user *, envp,
>> int, flags)
>> fs/exec.c:2083:
>> COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
>> const char __user *, filename,
>> const compat_uptr_t __user *, argv,
>> const compat_uptr_t __user *, envp,
>> int, flags)
>> include/linux/syscalls.h:980:
>> asmlinkage long sys_execveat(int dfd, const char __user *filename,
>> const char __user *const __user *argv,
>> const char __user *const __user *envp, int flags);
>> .../linux$
>>
>> function grep_syscall()
>> {
>> if ! [ -v 1 ]; then
>> >&2 echo "Usage: ${FUNCNAME[0]} <syscall>";
>> return ${EX_USAGE};
>> fi
>>
>> find * -type f \
>> |grep '\.c$' \
>> |sort -V \
>> |xargs pcregrep -Mn "(?s)^\w*SYSCALL_DEFINE.\(${1},.*?\)" \
>> |sed -E 's/^[^:]+:[0-9]+:/&\n/';
>>
>> find * -type f \
>> |grep '\.h$' \
>> |sort -V \
>> |xargs pcregrep -Mn "(?s)^asmlinkage \w+ \**sys_${1}\(.*?\)" \
>> |sed -E 's/^[^:]+:[0-9]+:/&\n/';
>> }
>>
>> Signed-off-by: Alejandro Colomar <alx.manpages@xxxxxxxxx>
>> ---
>> man2/execveat.2 | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/man2/execveat.2 b/man2/execveat.2
>> index 02d9c7331..d1ce4bee1 100644
>> --- a/man2/execveat.2
>> +++ b/man2/execveat.2
>> @@ -31,7 +31,7 @@ execveat \- execute program relative to a directory file descriptor
>> .B #include <unistd.h>
>> .PP
>> .BI "int execveat(int " dirfd ", const char *" pathname ,
>> -.BI " char *const " argv "[], char *const " envp [],
>> +.BI " const char *const " argv "[], const char *const " envp [],
>> .BI " int " flags );
>> .fi
>> .PP
>> --
>> 2.30.0
>>
>
>
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
