linux(4): Add a dedicated linux_exec_copyin_args()

[dchagin]

Summary

Because Linux allows to exec binaries with 0 argc.

MFC after: 1 week

[emaste]

Are we aware of any actual Linux binary use cases for argc=0? (I don't object to this change, just wondering.)

[dchagin]

In D40148#914234, @emaste wrote:

Are we aware of any actual Linux binary use cases for argc=0? (I don't object to this change, just wondering.)

well, I dont know, I’m not use Linux since 1997:)
I try to fix Glibc posix_spawn(), for which some glibc tests fails due to argc=0, also see comment in the linux_exec_copyin_args() explaining this change

sys/amd64/linux/syscalls.master

57      AUE_FORK        STD {
                 int linux_fork(void);
         }
 58      AUE_VFORK       STD {
                 int linux_vfork(void);
         }
 59      AUE_EXECVE      STD {
                 int linux_execve(
                     char *path,
-                    char **argp,
-                    char **envp
+                    l_uintptr_t *argp,
+                    l_uintptr_t *envp
                 );
         }
 60      AUE_EXIT        STD {
                 void linux_exit(
                     l_int rval
                 );
         }
 61      AUE_WAIT4       STD {

sys/amd64/linux32/linux32_machdep.c

 {
         struct l_rusage lru;
 
         bsd_to_linux_rusage(ru, &lru);
 
         return (copyout(&lru, uaddr, sizeof(struct l_rusage)));
 }
 
-int
-linux_execve(struct thread *td, struct linux_execve_args *args)
-{
-        struct image_args eargs;
-        int error;
-
-        error = freebsd32_exec_copyin_args(&eargs, args->path, UIO_USERSPACE,
-            args->argp, args->envp);
-        if (error == 0)
-                error = linux_common_execve(td, &eargs);
-        AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
-        return (error);
-}
-
 CTASSERT(sizeof(struct l_iovec32) == 8);
 
 int
 linux32_copyinuio(struct l_iovec32 *iovp, l_ulong iovcnt, struct uio **uiop)
 {
         struct l_iovec32 iov32;
         struct iovec *iov;
         struct uio *uio;

sys/amd64/linux32/syscalls.master

 10      AUE_UNLINK      STD {
                 int linux_unlink(
                     char *path
                 );
         }
 11      AUE_EXECVE      STD {
                 int linux_execve(
                     char *path,
-                    uint32_t *argp,
-                    uint32_t *envp
+                    l_uintptr_t *argp,
+                    l_uintptr_t *envp
                 );
         }
 12      AUE_CHDIR       STD {
                 int linux_chdir(
                     char *path
                 );
         }
 13      AUE_NULL        STD {

sys/arm64/linux/syscalls.master

int linux_clone(
                     l_int *parent_tidptr,
                     l_ulong tls,
                     l_int *child_tidptr
                 );
         }
 221     AUE_EXECVE      STD     {
                 int linux_execve(
                     char *path,
-                    char **argp,
-                    char **envp
+                    l_uintptr_t *argp,
+                    l_uintptr_t *envp
                 );
         }
 222     AUE_MMAP        STD     {
                 int linux_mmap2(
                     l_ulong addr,
                     l_ulong len,
                     l_ulong prot,
                     l_ulong flags,