lascar-el-usb: lascar_scan(): Fix USB device list leak

lascar_scan() calls libusb_get_device_list() but never the matching
libusb_free_device_list(). This will leak the memory allocated for the
device list as well as all the devices. To fix this add the missing
libusb_free_device_list().

While we are at it also make sure to handle errors returned by
libusb_get_device_list().

The issue was discovered using the following coccinelle semantic patch:
// <smpl>
@@
identifier devlist;
expression ctx, ret;
statement S;
@@
(
 libusb_get_device_list(ctx, &devlist);
|
 ret = libusb_get_device_list(ctx, &devlist);
 if (ret < 0) S
)
... when != libusb_free_device_list(devlist, ...)
*return ...;
// </smpl>

Signed-off-by: Lars-Peter Clausen <redacted>

diff --git a/src/hardware/lascar-el-usb/protocol.c b/src/hardware/lascar-el-usb/protocol.c
index e4fae68f5720d4df39e9fbac0d3001d94d43274a..f7b053f3bf19f45c7f1fd91c53b6181f5d75ec69 100644 (file)
--- a/src/hardware/lascar-el-usb/protocol.c
+++ b/src/hardware/lascar-el-usb/protocol.c
@@ -354,12 +354,16 @@ SR_PRIV struct sr_dev_inst *lascar_scan(int bus, int address)
        struct libusb_device **devlist;
        libusb_device_handle *dev_hdl;
        int dummy, i;
+       int ret;
        unsigned char config[MAX_CONFIGBLOCK_SIZE];
 
        drvc = di->context;
        sdi = NULL;
 
-       libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
+       ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
+       if (ret < 0)
+               return NULL;
+
        for (i = 0; devlist[i]; i++) {
                if (libusb_get_bus_number(devlist[i]) != bus ||
                                libusb_get_device_address(devlist[i]) != address)
@@ -374,6 +378,7 @@ SR_PRIV struct sr_dev_inst *lascar_scan(int bus, int address)
                libusb_close(dev_hdl);
                sdi = lascar_identify(config);
        }
+       libusb_free_device_list(devlist, 1);
 
        return sdi;
 }