Exposing SystemSpawn in libc and adding skeleton for basic shell.

SConstruct

@@ -161,6 +161,7 @@ CopyTree('build/include/machine', 'sys/' + env['ARCH'] + '/include', env)
 # Build Targets
 SConscript('sys/SConscript', variant_dir='build/sys')
 SConscript('lib/libc/SConscript', variant_dir='build/lib/libc')
+SConscript('bin/shell/SConscript', variant_dir='build/bin/shell')
 SConscript('sbin/init/SConscript', variant_dir='build/sbin/init')
 
 # Build Tools
@@ -180,6 +181,7 @@ if env["BOOTDISK"] == "1":
     env.Append(BUILDERS = {'BuildImage' : newfs})
     bootdisk = env.BuildImage('#build/bootdisk.img', '#release/bootdisk.manifest')
     Depends(bootdisk, "#build/tools/newfs_o2fs/newfs_o2fs")
+    Depends(bootdisk, "#build/bin/shell/shell")
     Depends(bootdisk, "#build/sbin/init/init")
     Depends(bootdisk, "#build/sys/castor")
     env.Alias('bootdisk', '#build/bootdisk.img')

bin/shell/SConscript

@@ -0,0 +1,21 @@
+import sys
+
+Import('env')
+
+init_env = env.Clone()
+
+src = [ ]
+
+src_common = [
+    "shell.c"
+]
+
+src.append(src_common)
+
+init_env.Append(LINKFLAGS = ['-nostdlib'])
+init_env.Append(CPPFLAGS = ['-nostdinc'])
+init_env.Append(CPPPATH = ['#build/include'])
+init_env.Append(LIBPATH = ['#build/lib/libc'], LIBS = ['c'])
+
+init_env.Program("shell", src)
+

bin/shell/shell.c

@@ -0,0 +1,15 @@
+
+#include <stdio.h>
+
+int
+main(int argc, const char *argv[])
+{
+    char buf[256];
+
+    fputs("Shell\n", stdout);
+    while (1) {
+	fputs("> ", stdout);
+	fgets(buf, sizeof(buf), stdin);
+    }
+}
+

include/errno.h

@@ -6,6 +6,7 @@
 #define EBADF		2
 #define EINVAL		3
 #define EFAULT		4
+#define ENOMEM		5
 
 #endif /* __ERRNO_H__ */
 

include/syscall.h

@@ -5,6 +5,7 @@
 uint64_t SystemTime();
 void SystemExit(int status);
 uint64_t SystemGetPID();
+uint64_t SystemSpawn(const char *path);
 
 // Memory
 void *SystemMemMap(void *addr, uint64_t len, int flags);

lib/libc/syscall.c

@@ -25,6 +25,12 @@ SystemGetPID()
     return syscall(SYSCALL_GETPID);
 }
 
+uint64_t
+SystemSpawn(const char *path)
+{
+    return syscall(SYSCALL_SPAWN, path);
+}
+
 void *
 SystemMemMap(void *addr, uint64_t len, int flags)
 {

release/bootdisk.manifest

@@ -4,6 +4,9 @@ DIR /
   END
   DIR dev
   END
+  DIR bin
+    FILE shell build/bin/shell/shell
+  END
   DIR sbin
     FILE init build/sbin/init/init
   END