From 33e3e8d63d99b607e713dc3fd5890130cfd48fbc Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Wed, 15 Jul 2020 23:44:51 +0200
Subject: [PATCH] UserspaceEmulator: Add the getrandom() syscall

---
 DevTools/UserspaceEmulator/Emulator.cpp | 16 +++++++++++++---
 DevTools/UserspaceEmulator/Emulator.h   |  1 +
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/DevTools/UserspaceEmulator/Emulator.cpp b/DevTools/UserspaceEmulator/Emulator.cpp
index f48780fc09..d8ac88057e 100644
--- a/DevTools/UserspaceEmulator/Emulator.cpp
+++ b/DevTools/UserspaceEmulator/Emulator.cpp
@@ -198,9 +198,6 @@ void Emulator::dump_backtrace()
 
 u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3)
 {
-    (void)arg2;
-    (void)arg3;
-
 #ifdef DEBUG_SPAM
     dbgprintf("Syscall: %s (%x)\n", Syscall::to_string((Syscall::Function)function), function);
 #endif
@@ -296,6 +293,9 @@ u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3)
         return virt$gettimeofday(arg1);
     case SC_clock_gettime:
         return virt$clock_gettime(arg1, arg2);
+    case SC_getrandom:
+        return virt$getrandom(arg1, arg2, arg3)       ;
+
     default:
         warn() << "Unimplemented syscall: " << Syscall::to_string((Syscall::Function)function);
         dump_backtrace();
@@ -738,4 +738,14 @@ void Emulator::virt$exit(int status)
     m_shutdown = true;
 }
 
+ssize_t Emulator::virt$getrandom(FlatPtr buffer, size_t buffer_size, unsigned int flags)
+{
+    auto host_buffer = ByteBuffer::create_uninitialized(buffer_size);
+    int rc = syscall(SC_getrandom, host_buffer.data(), host_buffer.size(), flags);
+    if (rc < 0)
+        return rc;
+    mmu().copy_to_vm(buffer, host_buffer.data(), host_buffer.size());
+    return rc;
+}
+
 }
diff --git a/DevTools/UserspaceEmulator/Emulator.h b/DevTools/UserspaceEmulator/Emulator.h
index d9cfc5e755..fbfcfee319 100644
--- a/DevTools/UserspaceEmulator/Emulator.h
+++ b/DevTools/UserspaceEmulator/Emulator.h
@@ -111,6 +111,7 @@ private:
     int virt$recvfrom(FlatPtr);
     int virt$connect(int sockfd, FlatPtr address, socklen_t address_size);
     void virt$exit(int);
+    ssize_t virt$getrandom(FlatPtr buffer, size_t buffer_size, unsigned int flags);
 
     FlatPtr allocate_vm(size_t size, size_t alignment);