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fix modbus-tcp change server to client config crash. #2549

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Merged
fengzeroz merged 1 commit into from
Aug 26, 2025
Merged

fix modbus-tcp change server to client config crash. #2549

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67 changes: 50 additions & 17 deletions plugins/modbus/modbus_tcp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -130,15 +130,23 @@ static int driver_uninit(neu_plugin_t *plugin)
modbus_stack_destroy(plugin->stack);
}

if (!plugin->is_server) {
// Repair: Release the corresponding IP memory according to the current
// mode.
if (plugin->is_server) {
if (plugin->param.params.tcp_server.ip != NULL) {
free(plugin->param.params.tcp_server.ip);
plugin->param.params.tcp_server.ip = NULL;
}
} else {
if (plugin->param.params.tcp_client.ip != NULL) {
free(plugin->param.params.tcp_client.ip);
plugin->param.params.tcp_client.ip = NULL;
}
if (plugin->param_backup.params.tcp_client.ip != NULL) {
free(plugin->param_backup.params.tcp_client.ip);
plugin->param_backup.params.tcp_client.ip = NULL;
}
}
// Fix: Release the backup IP memory.
if (plugin->param_backup.params.tcp_client.ip != NULL) {
free(plugin->param_backup.params.tcp_client.ip);
plugin->param_backup.params.tcp_client.ip = NULL;
}

neu_event_close(plugin->events);
Expand Down Expand Up @@ -282,33 +290,58 @@ static int driver_config(neu_plugin_t *plugin, const char *config)
plugin->address_base = address_base.v.val_int;

if (mode.v.val_int == 1) {
param.type = NEU_CONN_TCP_SERVER;
param.params.tcp_server.ip = host.v.val_str;
param.type = NEU_CONN_TCP_SERVER;
param.params.tcp_server.ip = strdup(
host.v.val_str); // fix: Create a copy instead of direct assignment
param.params.tcp_server.port = port.v.val_int;
param.params.tcp_server.start_listen = modbus_tcp_server_listen;
param.params.tcp_server.stop_listen = modbus_tcp_server_stop;
param.params.tcp_server.timeout = timeout.v.val_int;
param.params.tcp_server.max_link = 1;
plugin->is_server = true;
backup = false;

if (plugin->param.params.tcp_client.ip != NULL) {
free(plugin->param.params.tcp_client.ip);
plugin->param.params.tcp_client.ip = NULL;
// Fix: Release previous memory when switching to Server mode. Note: Due
// to union sharing memory, it is necessary to determine how to release
// based on the previous mode.
if (!plugin->is_server) {
// before client to server
if (plugin->param.params.tcp_client.ip != NULL) {
free(plugin->param.params.tcp_client.ip);
plugin->param.params.tcp_client.ip = NULL;
}
} else {
// before server to server
if (plugin->param.params.tcp_server.ip != NULL) {
free(plugin->param.params.tcp_server.ip);
plugin->param.params.tcp_server.ip = NULL;
}
}

plugin->is_server = true;

if (plugin->param_backup.params.tcp_client.ip != NULL) {
free(plugin->param_backup.params.tcp_client.ip);
plugin->param_backup.params.tcp_client.ip = NULL;
}
}
if (mode.v.val_int == 0) {
plugin->is_server = false;
param.type = NEU_CONN_TCP_CLIENT;

if (plugin->param.params.tcp_client.ip != NULL) {
free(plugin->param.params.tcp_client.ip);
plugin->param.params.tcp_client.ip = NULL;
param.type = NEU_CONN_TCP_CLIENT;
// Fix: Release memory based on the previous mode when switching to
// Client mode
if (plugin->is_server) {
// before server to client
if (plugin->param.params.tcp_server.ip != NULL) {
free(plugin->param.params.tcp_server.ip);
plugin->param.params.tcp_server.ip = NULL;
}
} else {
// before client to client
if (plugin->param.params.tcp_client.ip != NULL) {
free(plugin->param.params.tcp_client.ip);
plugin->param.params.tcp_client.ip = NULL;
}
}
plugin->is_server = false;

param.params.tcp_client.ip = strdup(host.v.val_str);
param.params.tcp_client.port = port.v.val_int;
Expand Down