Don't just have a single general-purpose buffer in probe_devices().

Have separate buffers for device pathnames and USB device descriptors;
that may take extra memory on the stack, but it makes the code somewhat
cleaner.

diff --git a/pcap-usb-linux.c b/pcap-usb-linux.c
index c495aa920f0d4b0bd4584ed69cb02b7e17380631..d6e368ddb6454d6d4f15a9534112846238f1199f 100644 (file)
--- a/pcap-usb-linux.c
+++ b/pcap-usb-linux.c
@@ -490,6 +490,8 @@ int usb_mmap(pcap_t* handle)
 
 #define USB_DT_DEVICE          1
 
 
 #define USB_DT_DEVICE          1
 

+#define USB_DEVICE_DESCRIPTOR_SIZE     18
+

 /* probe the descriptors of the devices attached to the bus */
 /* the descriptors will end up in the captured packet stream */
 /* and be decoded by external apps like wireshark */
 /* probe the descriptors of the devices attached to the bus */
 /* the descriptors will end up in the captured packet stream */
 /* and be decoded by external apps like wireshark */


@@ -500,12 +502,13 @@ probe_devices(int bus)
        struct usbdevfs_ctrltransfer ctrl;
        struct dirent* data;
        int ret = 0;
        struct usbdevfs_ctrltransfer ctrl;
        struct dirent* data;
        int ret = 0;

-       char buf[sizeof("/dev/bus/usb/000/") + NAME_MAX];
+       char busdevpath[sizeof("/dev/bus/usb/000/") + NAME_MAX];

        DIR* dir;
        DIR* dir;

+       char descriptor[USB_DEVICE_DESCRIPTOR_SIZE];

 
        /* scan usb bus directories for device nodes */
 
        /* scan usb bus directories for device nodes */

-       snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d", bus);
-       dir = opendir(buf);
+       snprintf(busdevpath, sizeof(busdevpath), "/dev/bus/usb/%03d", bus);
+       dir = opendir(busdevpath);

        if (!dir)
                return;
 
        if (!dir)
                return;
 


@@ -516,9 +519,9 @@ probe_devices(int bus)
                if (name[0] == '.')
                        continue;
 
                if (name[0] == '.')
                        continue;
 

-               snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d/%s", bus, data->d_name);
+               snprintf(busdevpath, sizeof(busdevpath), "/dev/bus/usb/%03d/%s", bus, data->d_name);

 
 

-               fd = open(buf, O_RDWR);
+               fd = open(busdevpath, O_RDWR);

                if (fd == -1)
                        continue;
 
                if (fd == -1)
                        continue;
 


@@ -531,15 +534,15 @@ probe_devices(int bus)
                ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
                ctrl.wValue = USB_DT_DEVICE << 8;
                ctrl.wIndex = 0;
                ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
                ctrl.wValue = USB_DT_DEVICE << 8;
                ctrl.wIndex = 0;

-               ctrl.wLength = sizeof(buf);
+               ctrl.wLength = sizeof(descriptor);

 #else
                ctrl.requesttype = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
                ctrl.request = USB_REQ_GET_DESCRIPTOR;
                ctrl.value = USB_DT_DEVICE << 8;
                ctrl.index = 0;
 #else
                ctrl.requesttype = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
                ctrl.request = USB_REQ_GET_DESCRIPTOR;
                ctrl.value = USB_DT_DEVICE << 8;
                ctrl.index = 0;

-               ctrl.length = sizeof(buf);
+               ctrl.length = sizeof(descriptor);

 #endif
 #endif

-               ctrl.data = buf;
+               ctrl.data = descriptor;

                ctrl.timeout = CTRL_TIMEOUT;
 
                ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
                ctrl.timeout = CTRL_TIMEOUT;
 
                ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);