From 8826ed6396c15697c2178c1d98b89c35b8ff7814 Mon Sep 17 00:00:00 2001
From: Ali Mashtizadeh <mashti@cs.stanford.edu>
Date: Tue, 25 Nov 2014 22:24:54 -0800
Subject: [PATCH] Exposing SystemSpawn in libc and adding skeleton for basic
 shell.

---
 SConstruct                |  2 ++
 bin/shell/SConscript      | 21 +++++++++++++++++++++
 bin/shell/shell.c         | 15 +++++++++++++++
 include/errno.h           |  1 +
 include/syscall.h         |  1 +
 lib/libc/syscall.c        |  6 ++++++
 release/bootdisk.manifest |  3 +++
 7 files changed, 49 insertions(+)
 create mode 100644 bin/shell/SConscript
 create mode 100644 bin/shell/shell.c

diff --git a/SConstruct b/SConstruct
index 496590f..1b9ecb5 100644
--- a/SConstruct
+++ b/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')
diff --git a/bin/shell/SConscript b/bin/shell/SConscript
new file mode 100644
index 0000000..212ebf0
--- /dev/null
+++ b/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)
+
diff --git a/bin/shell/shell.c b/bin/shell/shell.c
new file mode 100644
index 0000000..9475cef
--- /dev/null
+++ b/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);
+    }
+}
+
diff --git a/include/errno.h b/include/errno.h
index b59b6f9..d3d5330 100644
--- a/include/errno.h
+++ b/include/errno.h
@@ -6,6 +6,7 @@
 #define EBADF		2
 #define EINVAL		3
 #define EFAULT		4
+#define ENOMEM		5
 
 #endif /* __ERRNO_H__ */
 
diff --git a/include/syscall.h b/include/syscall.h
index afbbd36..a2e636d 100644
--- a/include/syscall.h
+++ b/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);
diff --git a/lib/libc/syscall.c b/lib/libc/syscall.c
index a39c097..09dce04 100644
--- a/lib/libc/syscall.c
+++ b/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)
 {
diff --git a/release/bootdisk.manifest b/release/bootdisk.manifest
index 4d2453b..cb37d8b 100644
--- a/release/bootdisk.manifest
+++ b/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