Add emulation for the CLONE_PIDFD flag of the clone() syscall.
This flag was added in Linux kernel 5.2.
Successfully tested on a x86-64 Linux host with hppa-linux target.
Can be verified by running the testsuite of the qcoro debian package,
which breaks hard and kills the currently logged-in user without this
patch.
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/linux-user/strace.c b/linux-user/strace.c
index 9ae5a812cd..8fa5c1ec3d 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -1097,6 +1097,7 @@ UNUSED static struct flags clone_flags[] = {
FLAG_GENERIC(CLONE_FS),
FLAG_GENERIC(CLONE_FILES),
FLAG_GENERIC(CLONE_SIGHAND),
+ FLAG_GENERIC(CLONE_PIDFD),
FLAG_GENERIC(CLONE_PTRACE),
FLAG_GENERIC(CLONE_VFORK),
FLAG_GENERIC(CLONE_PARENT),
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 24b25759be..0468a1bad7 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -213,7 +213,7 @@ struct file_clone_range {
/* Flags for fork which we can implement within QEMU itself */
#define CLONE_OPTIONAL_FORK_FLAGS \
- (CLONE_SETTLS | CLONE_PARENT_SETTID | \
+ (CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_PIDFD | \
CLONE_CHILD_CLEARTID | CLONE_CHILD_SETTID)
/* Flags for thread creation which we can implement within QEMU itself */
@@ -6747,6 +6747,17 @@ static int do_fork(CPUArchState *env, unsigned int
flags, abi_ulong newsp,
return -TARGET_EINVAL;
}
+#if !defined(__NR_pidfd_open) || !defined(TARGET_NR_pidfd_open)
+ if (flags & CLONE_PIDFD) {
+ return -TARGET_EINVAL;
+ }
+#endif
+
+ /* Can not allow CLONE_PIDFD with CLONE_PARENT_SETTID */
+ if ((flags & CLONE_PIDFD) && (flags & CLONE_PARENT_SETTID)) {
+ return -TARGET_EINVAL;
+ }
+
if (block_signals()) {
return -QEMU_ERESTARTSYS;
}
@@ -6774,6 +6785,20 @@ static int do_fork(CPUArchState *env, unsigned int
flags, abi_ulong newsp,
ts->child_tidptr = child_tidptr;
} else {
cpu_clone_regs_parent(env, flags);
+ if (flags & CLONE_PIDFD) {
+ int pid_fd = 0;
+#if defined(__NR_pidfd_open) && defined(TARGET_NR_pidfd_open)
+ int pid_child = ret;
+ pid_fd = pidfd_open(pid_child, 0);
+ if (pid_fd >= 0) {
+ fcntl(pid_fd, F_SETFD, fcntl(pid_fd, F_GETFL)
+ | FD_CLOEXEC);
+ } else {
+ pid_fd = 0;
+ }
+#endif
+ put_user_u32(pid_fd, parent_tidptr);
+ }
fork_end(0);
}
}