Add support for user specified instance dir name

The default instance dir of Occlum is ".occlum". User now can specify the name
by declaring environment variable "OCCLUM_INSTANCE_DIR"

src/Enclave.edl

@@ -15,7 +15,7 @@ enclave {
          *
          * @retval On success, return 0; otherwise, return -1.
          */
-        public int occlum_ecall_init([in, string] const char* log_level);
+        public int occlum_ecall_init([in, string] const char* log_level, [in, string] const char* instance_dir);
 
         /*
          * Create a new LibOS process to do the task specified by the given 

src/libos/src/config.rs

@@ -33,9 +33,8 @@ lazy_static! {
                 .cause_err(|e| errno!(EINVAL, "invalid config JSON"))?;
             Ok(config)
         }
-
+        let config_path = unsafe { format!("{}{}", INSTANCE_DIR, "/build/Occlum.json.protected") };
-        let config_path = "./.occlum/build/Occlum.json.protected";
+        match load_config(&config_path) {
-        match load_config(config_path) {
             Err(e) => {
                 error!("failed to load config: {}", e.backtrace());
                 panic!();

src/libos/src/entry.rs

@@ -11,7 +11,8 @@ use util::mem_util::from_untrusted::*;
 use util::sgx::allow_debug as sgx_allow_debug;
 use sgx_tse::*;
 
-const ENCLAVE_PATH: &'static str = ".occlum/build/lib/libocclum-libos.signed.so";
+pub static mut INSTANCE_DIR: String = String::new();
+static mut ENCLAVE_PATH: String = String::new();
 
 lazy_static! {
     static ref INIT_ONCE: Once = Once::new();
@@ -19,11 +20,13 @@ lazy_static! {
 }
 
 #[no_mangle]
-pub extern "C" fn occlum_ecall_init(log_level: *const c_char) -> i32 {
+pub extern "C" fn occlum_ecall_init(log_level: *const c_char, instance_dir: *const c_char) -> i32 {
     if HAS_INIT.load(Ordering::SeqCst) == true {
         return EXIT_STATUS_INTERNAL_ERROR;
     }
 
+    assert!(!instance_dir.is_null());
+
     let log_level = {
         let input_log_level = match parse_log_level(log_level) {
             Err(e) => {
@@ -52,6 +55,12 @@ pub extern "C" fn occlum_ecall_init(log_level: *const c_char) -> i32 {
 
         // Register exception handlers (support cpuid & rdtsc for now)
         register_exception_handlers();
+        unsafe {
+            let dir_str: &str = CStr::from_ptr(instance_dir).to_str().unwrap();
+            INSTANCE_DIR.push_str(dir_str);
+            ENCLAVE_PATH.push_str(&INSTANCE_DIR);
+            ENCLAVE_PATH.push_str("/build/lib/libocclum-libos.signed.so");
+        }
 
         HAS_INIT.store(true, Ordering::SeqCst);
     });
@@ -76,7 +85,8 @@ pub extern "C" fn occlum_ecall_new_process(
             return EXIT_STATUS_INTERNAL_ERROR;
         }
     };
-    let _ = backtrace::enable_backtrace(ENCLAVE_PATH, PrintFormat::Short);
+
+    let _ = unsafe { backtrace::enable_backtrace(&ENCLAVE_PATH, PrintFormat::Short) };
     panic::catch_unwind(|| {
         backtrace::__rust_begin_short_backtrace(|| {
             match do_new_process(&path, &args, &host_stdio_fds) {
@@ -97,7 +107,7 @@ pub extern "C" fn occlum_ecall_exec_thread(libos_pid: i32, host_tid: i32) -> i32
         return EXIT_STATUS_INTERNAL_ERROR;
     }
 
-    let _ = backtrace::enable_backtrace(ENCLAVE_PATH, PrintFormat::Short);
+    let _ = unsafe { backtrace::enable_backtrace(&ENCLAVE_PATH, PrintFormat::Short) };
     panic::catch_unwind(|| {
         backtrace::__rust_begin_short_backtrace(|| {
             match do_exec_thread(libos_pid as pid_t, host_tid as pid_t) {

src/pal/src/pal_api.c

@@ -34,7 +34,7 @@ int occlum_pal_init(const struct occlum_pal_attr* attr) {
     // automatically done by Intel SGX SDK).
     eid = pal_get_enclave_id();
     int ret;
-    sgx_status_t ecall_status = occlum_ecall_init(eid, &ret, attr->log_level);
+    sgx_status_t ecall_status = occlum_ecall_init(eid, &ret, attr->log_level, attr->instance_dir);
     if (ecall_status != SGX_SUCCESS) {
         const char* sgx_err = pal_get_sgx_error_msg(ecall_status);
         PAL_ERROR("Failed to do ECall: %s", sgx_err);

tools/occlum

@@ -3,8 +3,11 @@
 this_dir="$( cd "$( dirname "${BASH_SOURCE[0]}"  )" >/dev/null 2>&1 && pwd )"
 occlum_dir="$( cd "$( dirname "$this_dir/../../../"  )" >/dev/null 2>&1 && pwd )"
 
+if [ -z $OCCLUM_INSTANCE_DIR ];then
+    OCCLUM_INSTANCE_DIR=".occlum"
+fi
 working_dir=`pwd`
-context_dir="$working_dir/.occlum"
+context_dir="$working_dir/$OCCLUM_INSTANCE_DIR"
 
 SGX_SDK="${SGX_SDK:-/opt/intel/sgxsdk}"
 SGX_GDB="$SGX_SDK/bin/sgx-gdb"

tools/occlum-gen-default-occlum-json

@@ -1,4 +1,9 @@
 #!/bin/bash
+
+if [ -z $OCCLUM_INSTANCE_DIR ];then
+    OCCLUM_INSTANCE_DIR=".occlum"
+fi
+
 cat <<EOF
 {
     "vm": {
@@ -13,7 +18,7 @@ cat <<EOF
         {
             "target": "/",
             "type": "sefs",
-            "source": ".occlum/build/mount/__ROOT",
+            "source": "$OCCLUM_INSTANCE_DIR/build/mount/__ROOT",
             "options": {
                 "integrity_only": true,
                 "MAC": "$OCCLUM_CONF_ROOT_FS_MAC"
@@ -22,7 +27,7 @@ cat <<EOF
         {
             "target": "/root",
             "type": "sefs",
-            "source": ".occlum/run/mount/root"
+            "source": "$OCCLUM_INSTANCE_DIR/run/mount/root"
         },
         {
             "target": "/host",