Add basic support for CLONE_PIDFD, only fork-like clone without additional
flags. This is enough to make Qt/forkfd working.
Signed-off-by: Andreas Schwab <sch...@suse.de>
---
linux-user/syscall.c | 52 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 50 insertions(+), 2 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ccd3892b2d..ad0de26dd7 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -137,6 +137,9 @@
#ifndef CLONE_IO
#define CLONE_IO 0x80000000 /* Clone io context */
#endif
+#ifndef CLONE_PIDFD
+#define CLONE_PIDFD 0x00001000 /* set if a pidfd should be
placed in parent */
+#endif
/* We can't directly call the host clone syscall, because this will
* badly confuse libc (breaking mutexes, for example). So we must
@@ -163,7 +166,8 @@
/* Flags for fork which we can implement within QEMU itself */
#define CLONE_OPTIONAL_FORK_FLAGS \
(CLONE_SETTLS | CLONE_PARENT_SETTID | \
- CLONE_CHILD_CLEARTID | CLONE_CHILD_SETTID)
+ CLONE_CHILD_CLEARTID | CLONE_CHILD_SETTID | \
+ CLONE_PIDFD)
/* Flags for thread creation which we can implement within QEMU itself */
#define CLONE_OPTIONAL_THREAD_FLAGS \
@@ -488,6 +492,39 @@ _syscall4(int, sys_prlimit64, pid_t, pid, int, resource,
struct host_rlimit64 *, old_limit)
#endif
+#if defined __NR_clone2
+#define __NR_sys_clone2 __NR_clone2
+_syscall6(int, sys_clone2, int, flags, void *, child_stack, size_t, stack_size,
+ int *, ptid, int *, ctid, void *, newtls);
+#else
+#define __NR_sys_clone __NR_clone
+#if defined __cris__ || defined __s390x__
+_syscall5(int, sys_clone, void *, child_stack, int, flags, int *, ptid,
+ void *, newtls, int *, ctid);
+#elif defined __microblaze__
+_syscall6(int, sys_clone, int, flags, void *, child_stack, size_t, stack_size,
+ int *, ptid, void *, newtls, int *, ctid);
+#else
+/*
+ * Note: ctid and newtls are swapped on some architectures, but both are
+ * passed as NULL only for now.
+ */
+_syscall5(int, sys_clone, int, flags, void *, child_stack, int *, ptid,
+ int *, ctid, void *, newtls);
+#endif
+#endif
+static int sys_clone_pidfd(int flags, int *pidfd)
+{
+#ifdef __NR_clone2
+ return sys_clone2(flags, NULL, 0, pidfd, NULL, NULL);
+#elif defined __cris__ || defined __s390x__
+ return sys_clone(NULL, flags, pidfd, NULL, NULL);
+#elif defined __microblaze__
+ return sys_clone(flags, NULL, 0, pidfd, NULL, NULL);
+#else
+ return sys_clone(flags, NULL, pidfd, NULL, NULL);
+#endif
+}
#if defined(TARGET_NR_timer_create)
/* Maximum of 32 active POSIX timers allowed at any one time. */
@@ -6346,6 +6383,7 @@ static int do_fork(CPUArchState *env, unsigned int flags,
abi_ulong newsp,
CPUState *new_cpu;
CPUArchState *new_env;
sigset_t sigmask;
+ int pidfd;
flags &= ~CLONE_IGNORED_FLAGS;
@@ -6353,6 +6391,10 @@ static int do_fork(CPUArchState *env, unsigned int
flags, abi_ulong newsp,
if (flags & CLONE_VFORK)
flags &= ~(CLONE_VFORK | CLONE_VM);
+ /* Only basic fork-like clone is supported with CLONE_PIDFD for now. */
+ if (flags & CLONE_PIDFD && flags & ~(CLONE_PIDFD|CSIGNAL))
+ return -TARGET_EINVAL;
+
if (flags & CLONE_VM) {
TaskState *parent_ts = (TaskState *)cpu->opaque;
new_thread_info info;
@@ -6451,7 +6493,11 @@ static int do_fork(CPUArchState *env, unsigned int
flags, abi_ulong newsp,
}
fork_start();
- ret = fork();
+ if (flags & CLONE_PIDFD) {
+ ret = sys_clone_pidfd(flags, &pidfd);
+ } else {
+ ret = fork();
+ }
if (ret == 0) {
/* Child Process. */
cpu_clone_regs_child(env, newsp, flags);
@@ -6474,6 +6520,8 @@ static int do_fork(CPUArchState *env, unsigned int flags,
abi_ulong newsp,
} else {
cpu_clone_regs_parent(env, flags);
fork_end(0);
+ if (flags & CLONE_PIDFD)
+ put_user_u32(pidfd, parent_tidptr);
}
}
return ret;
--
2.32.0
--
Andreas Schwab, SUSE Labs, sch...@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
