Various cleanup:

 - Got rid of dummy proc[0].  Now proc[0] is init.
 - Added initcode.S to exec /init, so that /init is
   just a regular binary.
 - Moved exec out of sysfile to exec.c
 - Moved code dealing with fs guts (like struct inode)
   from sysfile.c to fs.c.  Code dealing with system call
   arguments stays in sysfile.c
 - Refactored directory routines in fs.c; should be simpler.
 - Changed iget to return *unlocked* inode structure.
   This solves the lookup-then-use race in namei
   without introducing deadlocks.
   It also enabled getting rid of the dummy proc[0].

1 files changed, 28 insertions, 0 deletions

diff --git a/initcode.S b/initcode.S
new file mode 100644
index 0000000..c87c4b1
--- /dev/null
+++ b/initcode.S
@@ -0,0 +1,28 @@
+# Initial process execs /init.
+
+#include "syscall.h"
+#include "traps.h"
+
+# exec(init, argv)
+start:
+  pushl $argv
+  pushl $init
+  pushl $0
+  movl $SYS_exec, %eax
+  int $T_SYSCALL
+
+# for(;;) exit();
+exit:
+  movl $SYS_exit, %eax
+  int $T_SYSCALL
+  jmp exit
+
+# "/init\0"
+init:
+  .string "/init\0"
+
+.p2align 2
+argv:
+  .long init
+  .long 0
+