Re: [PATCH v2 0/2] linux-user: handle /proc/self/exe with execve() syscall

[Michael Tokarev <mjt@tls.msk.ru>]

27.10.2022 13:42, Michael Tokarev wrote:
> 27.10.2022 09:40, Laurent Vivier wrote:
> ..
>> I tried O_CLOEXEC, but it seems the fd is closed before it is needed by execveat() to re-spawn the process, so it exits with an error (something 
>> like EBADF)
> 
> It works here for me with a simple test program:
> 
> #include <sys/types.h>
> #include <fcntl.h>
> #include <unistd.h>
> #include <sys/syscall.h>
> #define AT_EMPTY_PATH        0x1000
> 
> static char *argv[] = { "ls", NULL };
> static char *envp[] = { NULL };
> 
> int main(void) {
>    int fd = open("/usr/bin/ls", O_RDONLY);
>    fcntl(fd, F_SETFD, O_CLOEXEC);
>    //execveat(fd, "", argv, envp, AT_EMPTY_PATH);
>    syscall(__NR_execveat, fd, "", argv, envp, AT_EMPTY_PATH);
>    return 0;
> }

But for some reason it does not close this fd# on exec.

  static char *argv[] = { "ls", "-l", "/proc/self/fd", NULL };

shows this.

Hmm. Ok. Let's keep it the way you did :)

/mjt