[Asterisk-code-review] app_voicemail: Prevent deadlocks when out of ODBC database connections (asterisk[18])

[George Joseph]

George Joseph has submitted this change. ( https://gerrit.asterisk.org/c/asterisk/+/15276 )

Change subject: app_voicemail: Prevent deadlocks when out of ODBC database connections
......................................................................

app_voicemail: Prevent deadlocks when out of ODBC database connections

ASTERISK-28992 #close

Change-Id: Ia7d608924036139ee2520b840d077762d02668d0
---
M apps/app_voicemail.c
1 file changed, 10 insertions(+), 2 deletions(-)

Approvals:
  Joshua Colp: Looks good to me, but someone else must approve
  Benjamin Keith Ford: Looks good to me, but someone else must approve
  George Joseph: Looks good to me, approved; Approved for Submit



diff --git a/apps/app_voicemail.c b/apps/app_voicemail.c
index 1bb736b..2929cf2 100644
--- a/apps/app_voicemail.c
+++ b/apps/app_voicemail.c
@@ -3834,6 +3834,7 @@
 	char fn[PATH_MAX];
 	char full_fn[PATH_MAX];
 	char msgnums[80];
+	char msg_id[MSG_ID_LEN] = "";
 	char *argv[] = { dir, msgnums };
 	struct generic_prepare_struct gps = { .sql = sql, .argc = 2, .argv = argv };
 	struct odbc_obj *obj;
@@ -3938,10 +3939,10 @@
 		} else {
 			res = SQLGetData(stmt, x + 1, SQL_CHAR, rowdata, sizeof(rowdata), NULL);
 			if (res == SQL_NULL_DATA && !strcasecmp(coltitle, "msg_id")) {
-				char msg_id[MSG_ID_LEN];
+				/* Generate msg_id now, but don't store it until we're done with this
+				   connection */
 				generate_msg_id(msg_id);
 				snprintf(rowdata, sizeof(rowdata), "%s", msg_id);
-				odbc_update_msg_id(dir, msgnum, msg_id);
 			} else if (res == SQL_NULL_DATA && !strcasecmp(coltitle, "category")) {
 				/* Ignore null column value for category */
 				ast_debug(3, "Ignoring null category column in ODBC voicemail retrieve_file.\n");
@@ -3967,6 +3968,13 @@
 
 	ast_odbc_release_obj(obj);
 
+	/* If res_odbc is configured to only allow a single database connection, we
+	   will deadlock if we try to do this before releasing the connection we
+	   were just using. */
+	if (!ast_strlen_zero(msg_id)) {
+		odbc_update_msg_id(dir, msgnum, msg_id);
+	}
+
 	return x - 1;
 }
 

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Gerrit-Project: asterisk
Gerrit-Branch: 18
Gerrit-Change-Id: Ia7d608924036139ee2520b840d077762d02668d0
Gerrit-Change-Number: 15276
Gerrit-PatchSet: 2
Gerrit-Owner: Sean Bright <sean.bright at gmail.com>
Gerrit-Reviewer: Benjamin Keith Ford <bford at digium.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at sangoma.com>
Gerrit-MessageType: merged
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