add support of the system call "fork" in libgloss

include/metalsvm/syscall.h

@@ -38,6 +38,7 @@ extern "C" {
 #define __NR_kill		9
 #define __NR_fstat		10
 #define __NR_sbrk		11
+#define __NR_fork		12
 
 #ifdef __cplusplus
 }

kernel/syscall.c

@@ -21,6 +21,7 @@
 #include <metalsvm/stdio.h>
 #include <metalsvm/syscall.h>
 #include <metalsvm/tasks.h>
+#include <metalsvm/errno.h>
 
 static int sys_write(int fildes, const char *buf, size_t len)
 {
@@ -38,7 +39,7 @@ static int sys_write(int fildes, const char *buf, size_t len)
 
 int syscall_handler(uint32_t sys_nr, ...)
 {
-	int ret = -1;
+	int ret = -EINVAL;
 	va_list vl;
 
 	va_start(vl, sys_nr);
@@ -66,10 +67,11 @@ int syscall_handler(uint32_t sys_nr, ...)
 	case __NR_getpid:
 		ret = per_core(current_task)->id;
 		break;
+	case __NR_fork:
 	case __NR_fstat:
 	default:
 		kputs("invalid system call\n");
-		ret = -1;
+		ret = -EINVAL;
 		break;
 	};
 

newlib/src/libgloss/metalsvm/_exit.c

@@ -21,13 +21,19 @@
 #include "syscall.h"
 #include <_ansi.h>
 #include <_syslist.h>
+#undef errno
+extern int errno;
 
 _VOID
 _DEFUN (_exit, (rc),
 	int rc)
 {
+	int ret;
+
 	/* task exit */
-        SYSCALL1(__NR_exit, rc); 
+	ret = SYSCALL1(__NR_exit, rc); 
+	if (ret < 0)
+		errno = -ret;
 
 	/* Convince GCC that this function never returns.  */
 	for (;;)

newlib/src/libgloss/metalsvm/close.c

@@ -33,6 +33,10 @@ _DEFUN (close, (fildes),
 	int ret;
 
         ret = SYSCALL1(__NR_close, fildes);
+	if (ret < 0) {
+		errno = -ret;
+		ret = -1;
+	}
 
         return ret;
 }

newlib/src/libgloss/metalsvm/fork.c

@@ -24,11 +24,20 @@
 #undef errno
 extern int errno;
 #include "warning.h"
+#include "syscall.h"
 
 int
 _DEFUN (_fork, (),
         _NOARGS)
 {
-	errno = EAGAIN;
-	return -1;
+	int ret;
+
+	/* create a child process */
+	ret = SYSCALL0(__NR_fork);
+	if (ret < 0) {
+		errno = -ret;
+		ret = -1;
+	}
+
+	return ret;
 }

newlib/src/libgloss/metalsvm/getpid.c

@@ -33,6 +33,10 @@ _DEFUN (_getpid, (),
 	int ret;
 
         ret = SYSCALL0(__NR_getpid);
+	if (ret < 0) {
+		errno = -ret;
+		ret = -1;
+	}
 
         return ret;
 }

newlib/src/libgloss/metalsvm/open.c

@@ -35,6 +35,10 @@ _DEFUN (_open, (file, flags, mode),
 	int ret;
 
         ret = SYSCALL2(__NR_open, flags, mode);
+	if (ret < 0) {
+		errno = -ret;
+		ret = -1;
+	}
 
         return ret;
 }

newlib/src/libgloss/metalsvm/syscall.h

@@ -35,6 +35,7 @@ extern "C" {
 #define __NR_kill		9
 #define __NR_fstat		10
 #define __NR_sbrk		11
+#define __NR_fork		12
 
 #define _STR(token)             #token
 #define _SYSCALLSTR(x)          "int $" _STR(x) " "

newlib/src/libgloss/metalsvm/write.c

@@ -35,6 +35,10 @@ _DEFUN (write, (file, ptr, len),
 	int ret; 
 
         ret = SYSCALL3(__NR_write, file, ptr, len); 
+	if (ret < 0) {
+		errno = -ret;
+		ret = -1;
+	}
 
 	return ret;
 }