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bsd-user: Implement rfork(2) system call.

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Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20230925182425.3163-28-kariem.taha2.7@gmail.com>
This commit is contained in:
Stacey Son 2023-09-25 21:24:24 +03:00 committed by Warner Losh
parent 831a5a7fcb
commit 510eecbc86
2 changed files with 43 additions and 0 deletions
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39
bsd-user/freebsd/os-proc.h
View File

@ -219,4 +219,43 @@ static inline abi_long do_freebsd_vfork(void *cpu_env)
return do_freebsd_fork(cpu_env);
}
/* rfork(2) */
static inline abi_long do_freebsd_rfork(void *cpu_env, abi_long flags)
{
abi_long ret;
abi_ulong child_flag;
/*
* XXX We need to handle RFMEM here, as well. Neither are safe to execute
* as-is on x86 hosts because they'll split memory but not the stack,
* wreaking havoc on host architectures that use the stack to store the
* return address as both threads try to pop it off. Rejecting RFSPAWN
* entirely for now is ok, the only consumer at the moment is posix_spawn
* and it will fall back to classic vfork(2) if we return EINVAL.
*/
if ((flags & TARGET_RFSPAWN) != 0) {
return -TARGET_EINVAL;
}
fork_start();
ret = rfork(flags);
if (ret == 0) {
/* child */
child_flag = 1;
target_cpu_clone_regs(cpu_env, 0);
} else {
/* parent */
child_flag = 0;
}
/*
* The fork system call sets a child flag in the second return
* value: 0 for parent process, 1 for child process.
*/
set_second_rval(cpu_env, child_flag);
fork_end(child_flag);
return ret;
}
#endif /* BSD_USER_FREEBSD_OS_PROC_H */

4
bsd-user/freebsd/os-syscall.c
View File

@ -234,6 +234,10 @@ static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
ret = do_freebsd_vfork(cpu_env);
break;
case TARGET_FREEBSD_NR_rfork: /* rfork(2) */
ret = do_freebsd_rfork(cpu_env, arg1);
break;
case TARGET_FREEBSD_NR_execve: /* execve(2) */
ret = do_freebsd_execve(arg1, arg2, arg3);
break;