From 30c7ad75ac7284469a3044813870b6543c81bbb9 Mon Sep 17 00:00:00 2001
From: Jon Meredith <jmeredith@thehive.com>
Date: Tue, 2 Jun 2009 13:14:47 -0600
Subject: [PATCH] Replaced calls to getenv with
 erl_drv_getenv/G_DB_ENV->get_home.  The erlang docs say not to use getenv in
 erlang drivers as they are not thread safe. The places we were using them
 were very unlikley to have issues, but you never know.

---
 c_src/bdberl_drv.c | 47 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 14 deletions(-)

diff --git a/c_src/bdberl_drv.c b/c_src/bdberl_drv.c
index 645d3b0..6f89628 100644
--- a/c_src/bdberl_drv.c
+++ b/c_src/bdberl_drv.c
@@ -232,8 +232,9 @@ DRIVER_INIT(bdberl_drv)
         DB_THREAD;              /* Make the environment free-threaded */
 
     // Check for environment flag which indicates we want to use DB_SYSTEM_MEM
-    char* use_system_mem = getenv("BDBERL_SYSTEM_MEM");
-    if (use_system_mem != 0)
+    char value[1];
+    size_t value_size = sizeof(value);
+    if (erl_drv_getenv("BDBERL_SYSTEM_MEM", value, &value_size) >= 0)
     {
         flags |= DB_SYSTEM_MEM;
     }
@@ -266,9 +267,11 @@ DRIVER_INIT(bdberl_drv)
         // Use the BDBERL_MAX_DBS environment value to determine the max # of
         // databases to permit the VM to open at once. Defaults to 1024.
         G_DATABASES_SIZE = 1024;
-        char* max_dbs_str = getenv("BDBERL_MAX_DBS"); /* TODO: Use erl_drv_getenv */
-        if (max_dbs_str != 0)
+        char max_dbs_str[64];
+        value_size = sizeof(max_dbs_str);
+        if (erl_drv_getenv("BDBERL_MAX_DBS", max_dbs_str, &value_size) >= 0)
         {
+            assert(value_size < sizeof(max_dbs_str));
             G_DATABASES_SIZE = atoi(max_dbs_str);
             if (G_DATABASES_SIZE <= 0)
             {
@@ -278,9 +281,11 @@ DRIVER_INIT(bdberl_drv)
 
         // Use the BDBERL_TRICKLE_TIME and BDBERL_TRICKLE_PERCENTAGE to control how often
         // the trickle writer runs and what percentage of pages should be flushed.
-        char* trickle_time_str = getenv("BDBERL_TRICKLE_TIME");
-        if (trickle_time_str != 0)
+        char trickle_time_str[64];
+        value_size = sizeof(trickle_time_str);
+        if (erl_drv_getenv("BDBERL_TRICKLE_TIME", trickle_time_str, &value_size) >= 0)
         {
+            assert(value_size < sizeof(trickle_time_str));
             G_TRICKLE_INTERVAL = atoi(trickle_time_str);
             if (G_TRICKLE_INTERVAL <= 0)
             {
@@ -288,9 +293,12 @@ DRIVER_INIT(bdberl_drv)
             }
         }
 
-        char* trickle_percentage_str = getenv("BDBERL_TRICKLE_PERCENTAGE");
-        if (trickle_percentage_str != 0)
+        char trickle_percentage_str[64];
+        value_size = sizeof(trickle_percentage_str);
+        if (erl_drv_getenv("BDBERL_TRICKLE_PERCENTAGE", trickle_percentage_str, &value_size) >= 0)
         {
+            assert(value_size < sizeof(trickle_percentage_str));
+
             G_TRICKLE_PERCENTAGE = atoi(trickle_percentage_str);
             if (G_TRICKLE_PERCENTAGE <= 0)
             {
@@ -299,9 +307,12 @@ DRIVER_INIT(bdberl_drv)
         }
 
         // Initialize default page size
-        char* page_size_str = getenv("BDBERL_PAGE_SIZE");
-        if (page_size_str != 0)
+        char page_size_str[64];
+        value_size = sizeof(page_size_str);
+        if (erl_drv_getenv("BDBERL_PAGE_SIZE", page_size_str, &value_size) >= 0)
         {
+            assert(value_size < sizeof(page_size_str));
+
             // Convert to integer and only set it if it is a power of 2.
             unsigned int page_size = atoi(page_size_str);
             if (page_size != 0 && ((page_size & (~page_size +1)) == page_size))
@@ -329,9 +340,12 @@ DRIVER_INIT(bdberl_drv)
 
         // Use the BDBERL_CHECKPOINT_TIME environment value to determine the
         // interval between transaction checkpoints. Defaults to 1 hour.
-        char* cp_int_str = getenv("BDBERL_CHECKPOINT_TIME"); /* TODO: Use erl_drv_getenv */
-        if (cp_int_str != 0)
+        char cp_int_str[64];
+        value_size = sizeof(cp_int_str);
+        if (erl_drv_getenv("BDBERL_CHECKPOINT_TIME", cp_int_str, &value_size) >= 0)
         {
+            assert(value_size < sizeof(cp_int_str));
+
             G_CHECKPOINT_INTERVAL = atoi(cp_int_str);
             if (G_CHECKPOINT_INTERVAL <= 0)
             {
@@ -1370,11 +1384,14 @@ static void get_info(int target, void* values, BinHelper* bh)
         int rc = G_DB_ENV->get_lg_dir(G_DB_ENV, &dir);
         if (NULL == dir)
         {
-            dir = getenv("DB_HOME");
+            if (0 != G_DB_ENV->get_home(G_DB_ENV, &dir))
+            {
+                dir = NULL;
+            }
         }
         bin_helper_init(bh);
         bin_helper_push_int32(bh, rc);
-        bin_helper_push_string(bh, dir);
+        bin_helper_push_string(bh, dir); // Will convert NULL pointer to "<null>"
         break;
     }
     }
@@ -2188,11 +2205,13 @@ static void do_async_txnop(void* arg)
     }
     else if (d->async_op == CMD_TXN_COMMIT)
     {
+        assert(NULL != d->txn);
         rc = d->txn->commit(d->txn, d->async_flags);
         d->txn = 0;
     }
     else 
     {
+        assert(NULL != d->txn);
         rc = d->txn->abort(d->txn);
         d->txn = 0;
     }