From 15f08794021c59d4e059100b6ab0b799c03a17b1 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Wed, 15 Feb 2012 19:51:13 +0100
Subject: [PATCH] Noux: skeleton for getpid and fork

---
 ports/include/noux_session/noux_session.h |  4 ++
 ports/include/noux_session/sysio.h        |  6 +++
 ports/src/lib/libc_noux/plugin.cc         | 58 +++++++++++++++++++++++
 ports/src/noux/main.cc                    | 13 +++++
 4 files changed, 81 insertions(+)

diff --git a/ports/include/noux_session/noux_session.h b/ports/include/noux_session/noux_session.h
index 2bfed4dc7..f3a79e4fb 100644
--- a/ports/include/noux_session/noux_session.h
+++ b/ports/include/noux_session/noux_session.h
@@ -46,6 +46,8 @@ namespace Noux {
 			SYSCALL_FCHDIR,
 			SYSCALL_EXECVE,
 			SYSCALL_SELECT,
+			SYSCALL_FORK,
+			SYSCALL_GETPID,
 			SYSCALL_INVALID = -1
 		};
 
@@ -66,6 +68,8 @@ namespace Noux {
 			NOUX_DECL_SYSCALL_NAME(FCHDIR)
 			NOUX_DECL_SYSCALL_NAME(EXECVE)
 			NOUX_DECL_SYSCALL_NAME(SELECT)
+			NOUX_DECL_SYSCALL_NAME(FORK)
+			NOUX_DECL_SYSCALL_NAME(GETPID)
 			case SYSCALL_INVALID: return 0;
 			}
 			return 0;
diff --git a/ports/include/noux_session/sysio.h b/ports/include/noux_session/sysio.h
index 80be157e7..c04ce7a5d 100644
--- a/ports/include/noux_session/sysio.h
+++ b/ports/include/noux_session/sysio.h
@@ -247,6 +247,12 @@ namespace Noux {
 
 			SYSIO_DECL(select, { Select_fds fds; Select_timeout timeout; },
 			                   { Select_fds fds; });
+
+			SYSIO_DECL(fork,   { Genode::addr_t ip; Genode::addr_t sp;
+			                     Genode::addr_t parent_cap_addr; },
+			                   { int pid; });
+
+			SYSIO_DECL(getpid, { }, { int pid; });
 		};
 	};
 };
diff --git a/ports/src/lib/libc_noux/plugin.cc b/ports/src/lib/libc_noux/plugin.cc
index 1b7b58692..4d8d2b556 100644
--- a/ports/src/lib/libc_noux/plugin.cc
+++ b/ports/src/lib/libc_noux/plugin.cc
@@ -293,6 +293,64 @@ extern "C" int select(int nfds, fd_set *readfds, fd_set *writefds,
 }
 
 
+#include <setjmp.h>
+
+#include <base/crt0.h> /* for '_parent_cap', needed by 'fork' */
+#include <base/platform_env.h>
+
+
+static jmp_buf fork_jmp_buf;
+
+
+/*
+ * The new process created via fork will start its execution here.
+ */
+extern "C" void fork_trampoline()
+{
+	static_cast<Genode::Platform_env *>(Genode::env())->reload_parent_cap();
+
+	longjmp(fork_jmp_buf, 1);
+}
+
+
+extern "C" pid_t fork(void)
+{
+	/* stack used for executing 'fork_trampoline' */
+	enum { STACK_SIZE = 1024 };
+	static long stack[STACK_SIZE];
+
+	if (setjmp(fork_jmp_buf)) {
+
+		/* got here via longjmp from 'fork_trampoline' */
+
+		PDBG("fork: got here via longjmp");
+		return 0;
+
+	} else {
+
+		PDBG("fork: got here via normal control flow");
+
+		/* got here during the normal control flow of the fork call */
+		sysio()->fork_in.ip              = (Genode::addr_t)(&fork_trampoline);
+		sysio()->fork_in.sp              = (Genode::addr_t)(&stack[STACK_SIZE]);
+		sysio()->fork_in.parent_cap_addr = (Genode::addr_t)(&_parent_cap);
+
+		if (!noux()->syscall(Noux::Session::SYSCALL_FORK)) {
+			PERR("fork error %d", sysio()->error.general);
+		}
+
+		return sysio()->fork_out.pid;
+	}
+}
+
+
+extern "C" pid_t getpid(void)
+{
+	noux()->syscall(Noux::Session::SYSCALL_GETPID);
+	return sysio()->getpid_out.pid;
+}
+
+
 /*********************
  ** File operations **
  *********************/
diff --git a/ports/src/noux/main.cc b/ports/src/noux/main.cc
index ec56abb18..ba0c0568e 100644
--- a/ports/src/noux/main.cc
+++ b/ports/src/noux/main.cc
@@ -283,6 +283,19 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 				return true;
 			}
 
+		case SYSCALL_FORK:
+			{
+				PDBG("fork called - not implemented");
+				_sysio->fork_out.pid = 77;
+				return true;
+			}
+
+		case SYSCALL_GETPID:
+			{
+				_sysio->getpid_out.pid = _pid;
+				return true;
+			}
+
 		case SYSCALL_INVALID: break;
 		}
 	}