Add SQLite demo

demos/README.md

@@ -18,6 +18,7 @@ This set of demos shows how real-world apps can be easily run inside SGX enclave
 * `grpc/`: A client and server communicating through [gRPC](https://grpc.io/).
 * `openvino/` A benchmark of [OpenVINO Inference Engine](https://docs.openvinotoolkit.org/2019_R3/_docs_IE_DG_inference_engine_intro.html).
 * `python` A demo of [Python](https://www.python.org).
+* `sqlite` A demo of [SQLite](https://www.sqlite.org) SQL database engine.
 * `tensorflow_lite/`: A demo and benchmark of [Tensorflow Lite](https://www.tensorflow.org/lite) inference engine.
 * `xgboost/`: A demo of [XGBoost](https://xgboost.readthedocs.io/en/latest/).
 

demos/sqlite/.gitignore

@@ -0,0 +1,3 @@
+sqlite_src/
+occlum_context/
+sqlite_demo

demos/sqlite/README.md

@@ -0,0 +1,19 @@
+# Use SQLite in SGX with Occlum
+
+This project demonstrates how Occlum enables [SQLite](https://www.sqlite.org) in SGX enclaves.
+
+Step 1: Download SQLite and build the demo program
+```
+./download_and_build_sqlite.sh
+```
+When completed, the demo program (i.e., `sqlite_demo`) is generated.
+
+Step 2: Run the SQLite demo program inside SGX enclave with Occlum
+```
+./run_sqlite_on_occlum.sh
+```
+
+Step 3 (Optional): Run the SQLite demo program in Linux
+```
+./sqlite_demo <database> <sql-statement>
+```

demos/sqlite/download_and_build_sqlite.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+set -e
+
+SQLITE=sqlite-autoconf-3310100
+SQLITE_SRC=sqlite_src
+DEMO=sqlite_demo
+
+# Download SQLite source files
+[ ! -d $SQLITE_SRC ] && rm -f $SQLITE.tar.gz && \
+               wget http://www3.sqlite.org/2020/$SQLITE.tar.gz \
+               && rm -rf $SQLITE && tar xf $SQLITE.tar.gz \
+               && mv $SQLITE $SQLITE_SRC \
+               && rm -f $SQLITE.tar.gz
+
+[ -e $DEMO ] && rm -f $DEMO
+echo -e "Starting to build $DEMO ..."
+occlum-gcc -O2 -I$SQLITE_SRC sqlite_demo.c $SQLITE_SRC/sqlite3.c -lpthread -ldl -o $DEMO
+echo -e "Build $DEMO succeed"

demos/sqlite/run_sqlite_on_occlum.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+set -e
+
+DEMO=sqlite_demo
+SQL_DB=/root/company.db
+SQL_STMT="CREATE TABLE COMPANY ( \
+    ID INT PRIMARY KEY NOT NULL, \
+    NAME TEXT NOT NULL, \
+    AGE INT NOT NULL, \
+    ADDRESS CHAR(50), \
+    SALARY REAL ); \
+    INSERT INTO COMPANY VALUES ( 1, 'Kris', 27, 'California', 16000.00 ); \
+    SELECT * FROM COMPANY;"
+
+if [ ! -e $DEMO ];then
+    echo "Error: cannot stat '$DEMO'"
+    echo "Please see README and build the $DEMO"
+    exit 1
+fi
+
+# 1. Init Occlum Workspace
+rm -rf occlum_context && mkdir occlum_context
+cd occlum_context
+occlum init
+
+# 2. Copy files into Occlum Workspace and build
+cp ../$DEMO image/bin
+occlum build
+
+# 3. Run the demo
+occlum run /bin/$DEMO "$SQL_DB" "$SQL_STMT"

demos/sqlite/sqlite_demo.c

@@ -0,0 +1,50 @@
+/*
+ * Below is a simple C program that demonstrates how to use the C/C++ interface to SQLite.
+ * The name of a database is given by the first argument and the second argument is one
+ * or more SQL statements to execute against the database.
+ *
+ * This file is based on the sample code in https://www.sqlite.org/quickstart.html
+ */
+
+#include <stdio.h>
+#include <sqlite3.h>
+
+static int callback(void *NotUsed, int argc, char **argv, char **azColName) {
+    int i;
+    for (i=0; i < argc; i++) {
+        printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
+    }
+    printf("\n");
+    return 0;
+}
+
+int main(int argc, char **argv) {
+    sqlite3 *db;
+    char *db_path, *sql_stmt;
+    char *zErrMsg = 0;
+    int rc;
+
+    if (argc != 3) {
+        fprintf(stderr, "Usage: %s DATABASE SQL-STATEMENT\n", argv[0]);
+        return -1;
+    }
+    db_path = argv[1];
+    sql_stmt = argv[2];
+    rc = sqlite3_open(db_path, &db);
+    if (rc) {
+        fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
+        sqlite3_close(db);
+        return -1;
+    }
+    rc = sqlite3_exec(db, sql_stmt, callback, 0, &zErrMsg);
+    if (rc != SQLITE_OK) {
+        fprintf(stderr, "SQL error: %s\n", zErrMsg);
+        sqlite3_free(zErrMsg);
+        sqlite3_close(db);
+        return -1;
+    }
+    sqlite3_close(db);
+    fprintf(stdout, "Execute sql-statement: \"%s\"\non database: %s OK\n",
+            sql_stmt, db_path);
+    return 0;
+}