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Add appropriate locks to avoid race conditions. #15

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Add appropriate locks to avoid race conditions. #15

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58 changes: 40 additions & 18 deletions src/ngx_dynamic_upstream_op.c
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Original file line number Diff line number Diff line change
Expand Up @@ -230,13 +230,15 @@ static ngx_int_t
ngx_dynamic_upstream_op_add(ngx_http_request_t *r, ngx_dynamic_upstream_op_t *op,
ngx_slab_pool_t *shpool, ngx_http_upstream_srv_conf_t *uscf)
{
ngx_http_upstream_rr_peer_t *peer, *last;
ngx_http_upstream_rr_peer_t *peer, *last, *new_peer;
ngx_http_upstream_rr_peers_t *peers;
ngx_url_t u;

peers = uscf->peer.data;
ngx_http_upstream_rr_peers_wlock(peers);
for (peer = peers->peer, last = peer; peer; peer = peer->next) {
if (op->server.len == peer->name.len && ngx_strncmp(op->server.data, peer->name.data, peer->name.len) == 0) {
ngx_http_upstream_rr_peers_unlock(peers);
op->status = NGX_HTTP_BAD_REQUEST;
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"server %V already exists in upstream. %s:%d",
Expand All @@ -252,6 +254,7 @@ ngx_dynamic_upstream_op_add(ngx_http_request_t *r, ngx_dynamic_upstream_op_t *op

u.url.data = ngx_slab_alloc_locked(shpool, op->server.len);
if (u.url.data == NULL) {
ngx_http_upstream_rr_peers_unlock(peers);
op->status = NGX_HTTP_INTERNAL_SERVER_ERROR;
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"failed to allocate memory from slab %s:%d",
Expand All @@ -264,6 +267,7 @@ ngx_dynamic_upstream_op_add(ngx_http_request_t *r, ngx_dynamic_upstream_op_t *op
u.default_port = 80;

if (ngx_parse_url_slab(shpool, &u) != NGX_OK) {
ngx_http_upstream_rr_peers_unlock(peers);
if (u.err) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"%s in upstream \"%V\"", u.err, &u.url);
Expand All @@ -273,8 +277,9 @@ ngx_dynamic_upstream_op_add(ngx_http_request_t *r, ngx_dynamic_upstream_op_t *op
return NGX_ERROR;
}

last->next = ngx_slab_calloc_locked(shpool, sizeof(ngx_http_upstream_rr_peer_t));
if (last->next == NULL) {
new_peer = ngx_slab_calloc_locked(shpool, sizeof(ngx_http_upstream_rr_peer_t));
if (new_peer == NULL) {
ngx_http_upstream_rr_peers_unlock(peers);
op->status = NGX_HTTP_INTERNAL_SERVER_ERROR;
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"failed to allocate memory from slab %s:%d",
Expand All @@ -283,42 +288,46 @@ ngx_dynamic_upstream_op_add(ngx_http_request_t *r, ngx_dynamic_upstream_op_t *op
return NGX_ERROR;
}

last->next->name = u.url;
last->next->server = u.url;
last->next->sockaddr = u.addrs[0].sockaddr;
last->next->socklen = u.addrs[0].socklen;
new_peer->name = u.url;
new_peer->server = u.url;
new_peer->sockaddr = u.addrs[0].sockaddr;
new_peer->socklen = u.addrs[0].socklen;

if (op->op_param & NGX_DYNAMIC_UPSTEAM_OP_PARAM_WEIGHT) {
last->next->weight = op->weight;
last->next->effective_weight = op->weight;
last->next->current_weight = 0;
new_peer->weight = op->weight;
new_peer->effective_weight = op->weight;
new_peer->current_weight = 0;
} else {
last->next->weight = 1;
last->next->effective_weight = 1;
last->next->current_weight = 0;
new_peer->weight = 1;
new_peer->effective_weight = 1;
new_peer->current_weight = 0;
}

if (op->op_param & NGX_DYNAMIC_UPSTEAM_OP_PARAM_MAX_FAILS) {
last->next->max_fails = op->max_fails;
new_peer->max_fails = op->max_fails;
} else {
last->next->max_fails = 1;
new_peer->max_fails = 1;
}

if (op->op_param & NGX_DYNAMIC_UPSTEAM_OP_PARAM_FAIL_TIMEOUT) {
last->next->fail_timeout = op->fail_timeout;
new_peer->fail_timeout = op->fail_timeout;
} else {
last->next->fail_timeout = 10;
new_peer->fail_timeout = 10;
}

if (op->op_param & NGX_DYNAMIC_UPSTEAM_OP_PARAM_DOWN) {
last->next->down = op->down;
new_peer->down = op->down;
}

last->next = new_peer;

peers->number++;
peers->total_weight += last->next->weight;
peers->single = (peers->number == 1);
peers->weighted = (peers->total_weight != peers->number);

ngx_http_upstream_rr_peers_unlock(peers);

ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0,
"added server %V", &op->server);

Expand All @@ -335,8 +344,10 @@ ngx_dynamic_upstream_op_remove(ngx_http_request_t *r, ngx_dynamic_upstream_op_t
ngx_uint_t weight;

peers = uscf->peer.data;
ngx_http_upstream_rr_peers_wlock(peers);

if (peers->number < 2) {
ngx_http_upstream_rr_peers_unlock(peers);
op->status = NGX_HTTP_BAD_REQUEST;
return NGX_ERROR;
}
Expand All @@ -354,6 +365,7 @@ ngx_dynamic_upstream_op_remove(ngx_http_request_t *r, ngx_dynamic_upstream_op_t

/* not found */
if (target == NULL) {
ngx_http_upstream_rr_peers_unlock(peers);
op->status = NGX_HTTP_BAD_REQUEST;
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"server %V is not found. %s:%d",
Expand Down Expand Up @@ -395,6 +407,8 @@ ngx_dynamic_upstream_op_remove(ngx_http_request_t *r, ngx_dynamic_upstream_op_t
peers->single = (peers->number == 1);
peers->weighted = (peers->total_weight != peers->number);

ngx_http_upstream_rr_peers_unlock(peers);

ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0,
"removed server %V", &op->server);

Expand All @@ -411,6 +425,8 @@ ngx_dynamic_upstream_op_update_param(ngx_http_request_t *r, ngx_dynamic_upstream

peers = uscf->peer.data;

ngx_http_upstream_rr_peers_rlock(peers);

target = NULL;
for (peer = peers->peer; peer ; peer = peer->next) {
if (op->server.len == peer->name.len && ngx_strncmp(op->server.data, peer->name.data, peer->name.len) == 0) {
Expand All @@ -419,6 +435,8 @@ ngx_dynamic_upstream_op_update_param(ngx_http_request_t *r, ngx_dynamic_upstream
}
}

ngx_http_upstream_rr_peers_unlock(peers);

if (target == NULL) {
op->status = NGX_HTTP_BAD_REQUEST;
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
Expand All @@ -428,6 +446,8 @@ ngx_dynamic_upstream_op_update_param(ngx_http_request_t *r, ngx_dynamic_upstream
__LINE__);
return NGX_ERROR;
}

ngx_http_upstream_rr_peer_lock(peers, target);

if (op->op_param & NGX_DYNAMIC_UPSTEAM_OP_PARAM_WEIGHT) {
target->weight = op->weight;
Expand Down Expand Up @@ -455,5 +475,7 @@ ngx_dynamic_upstream_op_update_param(ngx_http_request_t *r, ngx_dynamic_upstream
"upped server %V", &op->server);
}

ngx_http_upstream_rr_peer_unlock(peers, target);

return NGX_OK;
}