lib/posix-process/signal: Add rt_sigtimedwait()

rt_sigtimedwait() suspends the execution of the calling thread until a
signal in a caller-provided mask is pending, or a caller provided
timeout is reached. For more info see sigwaitinfo(2)

Signed-off-by: Michalis Pappas <michalis@unikraft.io>
Reviewed-by: Ioan-Teodor Teugea <ioan_teodor.teugea@stud.acs.upb.ro>
Reviewed-by: Sergiu Moga <sergiu@unikraft.io>
Reviewed-by: Andrei Tatar <andrei@unikraft.io>
Approved-by: Andrei Tatar <andrei@unikraft.io>
GitHub-Closes: #1248

diff --git a/lib/posix-process/Makefile.uk b/lib/posix-process/Makefile.uk
index d256cfdbb3ab068fe2624901e3a43d70481cd306..d43f420ce5eea62d48a8f18d3ce37c4e7565cf20 100644 (file)
--- a/lib/posix-process/Makefile.uk
+++ b/lib/posix-process/Makefile.uk
@@ -30,6 +30,7 @@ LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/rt_sigsuspend.c
 LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/rt_sigaction.c
 LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/rt_sigqueueinfo.c
 LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/rt_tgsigqueueinfo.c
+LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/rt_sigtimedwait.c
 LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/kill.c
 LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/tgkill.c
 LIBPOSIX_PROCESS_SRCS-y += $(LIBPOSIX_PROCESS_BASE)/signal/tkill.c
@@ -58,6 +59,7 @@ UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += rt_sigsuspend-2
 UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += rt_sigaction-4
 UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += rt_sigqueueinfo-3
 UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += rt_tgsigqueueinfo-4
+UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += rt_sigtimedwait-4
 UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += kill-2
 UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += tgkill-3
 UK_PROVIDED_SYSCALLS-$(CONFIG_LIBPOSIX_PROCESS) += tkill-2

diff --git a/lib/posix-process/signal/rt_sigtimedwait.c b/lib/posix-process/signal/rt_sigtimedwait.c
new file mode 100644 (file)
index 0000000..bd7fbda
--- /dev/null
+++ b/lib/posix-process/signal/rt_sigtimedwait.c
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/* Copyright (c) 2023, Unikraft GmbH and The Unikraft Authors.
+ * Licensed under the BSD-3-Clause License (the "License").
+ * You may not use this file except in compliance with the License.
+ */
+
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+#include <uk/essentials.h>
+#include <uk/syscall.h>
+#include <uk/timeutil.h>
+
+#include "process.h"
+#include "signal.h"
+
+#if CONFIG_LIBPOSIX_PROCESS_SIGNAL
+UK_LLSYSCALL_R_DEFINE(int, rt_sigtimedwait,
+                     const uk_sigset_t *, set,
+                     siginfo_t *, info,
+                     const struct timespec *, timeout,
+                     size_t, sigsetsize)
+{
+       struct posix_thread *pthread;
+       struct uk_signal *sig;
+
+       if (unlikely(!set))
+               return -EINVAL;
+
+       if (unlikely(sigsetsize != sizeof(sigset_t)))
+               return -EINVAL;
+
+       pthread = uk_pthread_current();
+       UK_ASSERT(pthread);
+
+       /* TODO protect concurrent access by deliver_pending_proc() */
+       uk_sigcopyset(&pthread->signal->sigwait_set, set);
+
+       /* If a signal in the set is already pending return immediately */
+       if ((sig = pprocess_signal_next_pending_t(pthread)))
+               goto out;
+
+       if (timeout)
+               uk_semaphore_down_to(&pthread->signal->pending_semaphore,
+                                    uk_time_spec_to_nsec(timeout));
+       else
+               uk_semaphore_down(&pthread->signal->pending_semaphore);
+
+       if ((sig = pprocess_signal_next_pending_t(pthread)))
+               goto out;
+
+       return -EAGAIN;
+out:
+       if (info)
+               *info = sig->siginfo;
+       uk_sigemptyset(&pthread->signal->sigwait_set);
+       return sig->siginfo.si_signo;
+}
+#else /* !CONFIG_LIBPOSIX_PROCESS_SIGNAL */
+UK_LLSYSCALL_R_DEFINE(int, rt_sigtimedwait,
+                     const uk_sigset_t *, set,
+                     siginfo_t *, info,
+                     const struct timespec *, timeout,
+                     size_t, sigsetsize)
+{
+       UK_WARN_STUBBED();
+       *info = (siginfo_t){0};
+       info->si_signo = SIGINT;
+       return 0;
+}
+#endif /* !CONFIG_LIBPOSIX_PROCESS_SIGNAL */