mirror of
https://github.com/rtlsdrblog/rtl-sdr-blog.git
synced 2024-12-28 11:58:30 +01:00
lib: Fix race condition after cancellation of USB transfers
This commit is contained in:
Gonzalo José Carracedo Carballal
parent
031a044e31
commit
c16a86b269
405
src/librtlsdr.c
405
src/librtlsdr.c
@ -92,18 +92,56 @@ static const int fir_default[FIR_LEN] = {
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101, 156, 215, 273, 327, 372, 404, 421 /* 12 bit signed */
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};
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struct rtlsdr_dev;
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/*
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* RTL-SDR transfer context.
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*
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* Proper transfer cancellation is a stateful operation that involves
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* delivering an asynchronous cancellation request and waiting for its
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* completion. This is necessary to prevent a race condition during
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* cleanup when the device is closed (especially in Win32 systems).
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*
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* The rtlsdr_xfer_ctx structure encapsulates a transfer state, including
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* its buffer, its completion status and a pointer to the device it
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* belongs to.
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*/
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struct rtlsdr_xfer_ctx {
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struct rtlsdr_dev *dev;
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struct libusb_transfer *xfer;
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unsigned char *buffer;
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int done;
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int zero_copy;
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};
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typedef struct rtlsdr_xfer_ctx rtlsdr_xfer_ctx_t;
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static rtlsdr_xfer_ctx_t *rtlsdr_xfer_ctx_new(struct rtlsdr_dev *dev);
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static int rtlsdr_xfer_ctx_alloc_buffer(rtlsdr_xfer_ctx_t *self);
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static void rtlsdr_xfer_ctx_free_buffer(rtlsdr_xfer_ctx_t *self);
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static int rtlsdr_xfer_ctx_issue_transfer(rtlsdr_xfer_ctx_t *self);
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static void LIBUSB_CALL _rtlsdr_xfer_libusb_callback(
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struct libusb_transfer *xfer);
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static void rtlsdr_xfer_ctx_destroy(rtlsdr_xfer_ctx_t *self);
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#define rtlsdr_xfer_ctx_status(self) \
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((self)->xfer->status)
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/* Friend of rtlsdr_xfer_ctx */
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struct rtlsdr_dev {
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libusb_context *ctx;
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struct libusb_device_handle *devh;
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uint32_t xfer_buf_num;
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rtlsdr_xfer_ctx_t **xfer_ctx_list;
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uint32_t xfer_ctx_num;
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uint32_t xfer_buf_len;
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struct libusb_transfer **xfer;
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unsigned char **xfer_buf;
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rtlsdr_read_async_cb_t cb;
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void *cb_ctx;
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enum rtlsdr_async_status async_status;
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int async_cancel;
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int use_zerocopy;
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/* rtl demod context */
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uint32_t rate; /* Hz */
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uint32_t rtl_xtal; /* Hz */
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@ -1718,157 +1756,259 @@ int rtlsdr_read_sync(rtlsdr_dev_t *dev, void *buf, int len, int *n_read)
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return libusb_bulk_transfer(dev->devh, 0x81, buf, len, n_read, BULK_TIMEOUT);
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}
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static void LIBUSB_CALL _libusb_callback(struct libusb_transfer *xfer)
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{
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rtlsdr_dev_t *dev = (rtlsdr_dev_t *)xfer->user_data;
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if (LIBUSB_TRANSFER_COMPLETED == xfer->status) {
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if (dev->cb)
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dev->cb(xfer->buffer, xfer->actual_length, dev->cb_ctx);
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libusb_submit_transfer(xfer); /* resubmit transfer */
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dev->xfer_errors = 0;
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} else if (LIBUSB_TRANSFER_CANCELLED != xfer->status) {
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#ifndef _WIN32
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if (LIBUSB_TRANSFER_ERROR == xfer->status)
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dev->xfer_errors++;
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if (dev->xfer_errors >= dev->xfer_buf_num ||
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LIBUSB_TRANSFER_NO_DEVICE == xfer->status) {
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#endif
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dev->dev_lost = 1;
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rtlsdr_cancel_async(dev);
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fprintf(stderr, "cb transfer status: %d, "
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"canceling...\n", xfer->status);
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#ifndef _WIN32
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}
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#endif
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}
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}
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int rtlsdr_wait_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx)
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{
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return rtlsdr_read_async(dev, cb, ctx, 0, 0);
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}
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static int _rtlsdr_alloc_async_buffers(rtlsdr_dev_t *dev)
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static void
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rtlsdr_xfer_ctx_free_buffer(rtlsdr_xfer_ctx_t *self)
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{
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unsigned int i;
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/*
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* This path is excersed only if we managed to
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* allocate a buffer, which in turn only happens if
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* self->dev->xfer_buf_len is set to something meaningful
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*/
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if (!dev)
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return -1;
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if (self->buffer != NULL) {
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if (self->zero_copy) {
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#if defined (__linux__) && LIBUSB_API_VERSION >= 0x01000105
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libusb_dev_mem_free(
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self->dev->devh,
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self->buffer,
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self->dev->xfer_buf_len);
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#endif /* __linux__ */
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} else {
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free(self->buffer);
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}
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}
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}
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if (!dev->xfer) {
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dev->xfer = malloc(dev->xfer_buf_num *
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sizeof(struct libusb_transfer *));
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static int
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rtlsdr_xfer_ctx_cancel(rtlsdr_xfer_ctx_t *self)
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{
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int r = 0;
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for(i = 0; i < dev->xfer_buf_num; ++i)
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dev->xfer[i] = libusb_alloc_transfer(0);
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struct timeval zero_tv = {0, 0};
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self->done = 0;
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r = libusb_cancel_transfer(self->xfer);
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while (!self->done) {
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libusb_handle_events_timeout_completed(
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self->dev->ctx,
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&zero_tv,
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&self->done);
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}
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if (dev->xfer_buf)
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return -2;
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return r;
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}
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dev->xfer_buf = malloc(dev->xfer_buf_num * sizeof(unsigned char *));
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memset(dev->xfer_buf, 0, dev->xfer_buf_num * sizeof(unsigned char *));
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static int
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rtlsdr_xfer_ctx_issue_transfer(rtlsdr_xfer_ctx_t *self)
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{
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self->done = 0;
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libusb_fill_bulk_transfer(
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self->xfer,
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self->dev->devh,
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0x81,
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self->buffer,
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self->dev->xfer_buf_len,
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_rtlsdr_xfer_libusb_callback,
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self,
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BULK_TIMEOUT);
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return libusb_submit_transfer(self->xfer);
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}
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static int
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rtlsdr_xfer_ctx_alloc_buffer(rtlsdr_xfer_ctx_t *self)
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{
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int ok = 0;
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uint32_t buf_len = self->dev->xfer_buf_len;
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self->buffer = NULL;
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self->zero_copy = 0;
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#if defined(ENABLE_ZEROCOPY) && defined (__linux__) && LIBUSB_API_VERSION >= 0x01000105
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fprintf(stderr, "Allocating %d zero-copy buffers\n", dev->xfer_buf_num);
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self->buffer = libusb_dev_mem_alloc(self->dev->devh, buf_len);
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dev->use_zerocopy = 1;
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for (i = 0; i < dev->xfer_buf_num; ++i) {
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dev->xfer_buf[i] = libusb_dev_mem_alloc(dev->devh, dev->xfer_buf_len);
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if (dev->xfer_buf[i]) {
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/* Check if Kernel usbfs mmap() bug is present: if the
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* mapping is correct, the buffers point to memory that
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* was memset to 0 by the Kernel, otherwise, they point
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* to random memory. We check if the buffers are zeroed
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* and otherwise fall back to buffers in userspace.
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*/
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if (dev->xfer_buf[i][0] || memcmp(dev->xfer_buf[i],
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dev->xfer_buf[i] + 1,
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dev->xfer_buf_len - 1)) {
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fprintf(stderr, "Detected Kernel usbfs mmap() "
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"bug, falling back to buffers "
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"in userspace\n");
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dev->use_zerocopy = 0;
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break;
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}
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if (self->buffer != NULL) {
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/* Check if Kernel usbfs mmap() bug is present: if the
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* mapping is correct, the buffers point to memory that
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* was memset to 0 by the Kernel, otherwise, they point
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* to random memory. We check if the buffers are zeroed
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* and otherwise fall back to buffers in userspace.
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*/
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if (self->buffer[0] || memcmp(self->buffer,
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self->buffer + 1,
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buf_len - 1)) {
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fprintf(stderr, "Detected Kernel usbfs mmap() "
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"bug, falling back to buffers "
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"in userspace\n");
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} else {
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fprintf(stderr, "Failed to allocate zero-copy "
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"buffer for transfer %d\nFalling "
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"back to buffers in userspace\n", i);
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dev->use_zerocopy = 0;
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break;
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/* All looks good! Green light to zerocopy */
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self->zero_copy = 1;
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}
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}
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/* zero-copy buffer allocation failed (partially or completely)
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* we need to free the buffers again if already allocated */
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if (!dev->use_zerocopy) {
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for (i = 0; i < dev->xfer_buf_num; ++i) {
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if (dev->xfer_buf[i])
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libusb_dev_mem_free(dev->devh,
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dev->xfer_buf[i],
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dev->xfer_buf_len);
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}
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/*
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* Zero copy buffer allocation failed. We just need to free the
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* failed ones, as the current implementation allows mixed
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* userspace / zero-copy buffers.
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*/
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if (!self->zero_copy && self->buffer != NULL) {
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libusb_dev_mem_free(
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self->dev->devh,
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self->buffer,
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buf_len);
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self->buffer = NULL;
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}
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#endif
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/* no zero-copy available, allocate buffers in userspace */
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if (!dev->use_zerocopy) {
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for (i = 0; i < dev->xfer_buf_num; ++i) {
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dev->xfer_buf[i] = malloc(dev->xfer_buf_len);
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/* No zero copy, allocate in userspace */
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if (!self->zero_copy)
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if ((self->buffer = malloc(buf_len)) == NULL)
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goto done;
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if (!dev->xfer_buf[i])
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return -ENOMEM;
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}
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ok = 1;
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done:
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return ok;
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}
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rtlsdr_xfer_ctx_t *rtlsdr_xfer_ctx_new(struct rtlsdr_dev *dev)
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{
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rtlsdr_xfer_ctx_t *new = NULL;
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if (dev == NULL)
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return NULL;
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if ((new = calloc(1, sizeof(rtlsdr_xfer_ctx_t))) == NULL)
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goto fail;
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new->dev = dev;
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if ((new->xfer = libusb_alloc_transfer(0)) == NULL)
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goto fail;
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if (!rtlsdr_xfer_ctx_alloc_buffer(new))
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goto fail;
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return new;
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fail:
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if (new != NULL)
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rtlsdr_xfer_ctx_destroy(new);
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return NULL;
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}
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static void LIBUSB_CALL _rtlsdr_xfer_libusb_callback(
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struct libusb_transfer *xfer)
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{
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rtlsdr_xfer_ctx_t *ctx = (rtlsdr_xfer_ctx_t *) xfer->user_data;
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rtlsdr_dev_t *dev = ctx->dev;
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switch (xfer->status) {
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case LIBUSB_TRANSFER_COMPLETED:
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if (dev->cb)
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dev->cb(xfer->buffer, xfer->actual_length, dev->cb_ctx);
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libusb_submit_transfer(xfer); /* resubmit transfer */
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dev->xfer_errors = 0;
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ctx->done = 1;
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break;
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case LIBUSB_TRANSFER_CANCELLED:
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ctx->done = 1;
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break;
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default:
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/* Maybe an error */
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#ifndef _WIN32
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if (LIBUSB_TRANSFER_ERROR == xfer->status)
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dev->xfer_errors++;
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if (dev->xfer_errors >= dev->xfer_ctx_num ||
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LIBUSB_TRANSFER_NO_DEVICE == xfer->status) {
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#endif
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dev->dev_lost = 1;
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rtlsdr_cancel_async(dev);
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fprintf(stderr, "cb transfer status: %d, "
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"canceling...\n", xfer->status);
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#ifndef _WIN32
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}
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#endif
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}
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}
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return 0;
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void
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rtlsdr_xfer_ctx_destroy(rtlsdr_xfer_ctx_t *self)
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{
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if (self->xfer != NULL)
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libusb_free_transfer(self->xfer);
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rtlsdr_xfer_ctx_free_buffer(self);
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free(self);
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}
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static int _rtlsdr_free_async_buffers(rtlsdr_dev_t *dev)
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{
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unsigned int i;
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if (!dev)
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if (dev == NULL)
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return -1;
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if (dev->xfer) {
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for(i = 0; i < dev->xfer_buf_num; ++i) {
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if (dev->xfer[i]) {
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libusb_free_transfer(dev->xfer[i]);
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}
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}
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if (dev->xfer_ctx_list != NULL) {
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for (i = 0; i < dev->xfer_ctx_num; ++i)
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if (dev->xfer_ctx_list[i] != NULL)
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rtlsdr_xfer_ctx_destroy(dev->xfer_ctx_list[i]);
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free(dev->xfer);
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dev->xfer = NULL;
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}
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if (dev->xfer_buf) {
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for (i = 0; i < dev->xfer_buf_num; ++i) {
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if (dev->xfer_buf[i]) {
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if (dev->use_zerocopy) {
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#if defined (__linux__) && LIBUSB_API_VERSION >= 0x01000105
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libusb_dev_mem_free(dev->devh,
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dev->xfer_buf[i],
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dev->xfer_buf_len);
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#endif
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} else {
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free(dev->xfer_buf[i]);
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}
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}
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}
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free(dev->xfer_buf);
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dev->xfer_buf = NULL;
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free(dev->xfer_ctx_list);
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dev->xfer_ctx_list = NULL;
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}
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return 0;
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}
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static int _rtlsdr_alloc_async_buffers(rtlsdr_dev_t *dev)
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{
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unsigned int i;
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int ret = -1;
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if (dev == NULL)
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goto done;
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if (dev->xfer_ctx_list == NULL) {
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/* Lazy allocation of async buffers */
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if ((dev->xfer_ctx_list = calloc(
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dev->xfer_ctx_num,
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sizeof(rtlsdr_xfer_ctx_t *))) == NULL)
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goto done;
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for (i = 0; i < dev->xfer_ctx_num; ++i) {
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dev->xfer_ctx_list[i] = rtlsdr_xfer_ctx_new(dev);
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if (dev->xfer_ctx_list[i] == NULL)
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goto done;
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}
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}
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ret = 0;
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done:
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if (ret != 0)
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_rtlsdr_free_async_buffers(dev);
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return ret;
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}
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int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
|
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uint32_t buf_num, uint32_t buf_len)
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{
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@ -1891,9 +2031,9 @@ int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
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dev->cb_ctx = ctx;
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if (buf_num > 0)
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dev->xfer_buf_num = buf_num;
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dev->xfer_ctx_num = buf_num;
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else
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dev->xfer_buf_num = DEFAULT_BUF_NUMBER;
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dev->xfer_ctx_num = DEFAULT_BUF_NUMBER;
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if (buf_len > 0 && buf_len % 512 == 0) /* len must be multiple of 512 */
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dev->xfer_buf_len = buf_len;
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@ -1902,17 +2042,9 @@ int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
|
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|
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_rtlsdr_alloc_async_buffers(dev);
|
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|
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for(i = 0; i < dev->xfer_buf_num; ++i) {
|
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libusb_fill_bulk_transfer(dev->xfer[i],
|
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dev->devh,
|
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0x81,
|
||||
dev->xfer_buf[i],
|
||||
dev->xfer_buf_len,
|
||||
_libusb_callback,
|
||||
(void *)dev,
|
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BULK_TIMEOUT);
|
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for(i = 0; i < dev->xfer_ctx_num; ++i) {
|
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r = rtlsdr_xfer_ctx_issue_transfer(dev->xfer_ctx_list[i]);
|
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|
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r = libusb_submit_transfer(dev->xfer[i]);
|
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if (r < 0) {
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fprintf(stderr, "Failed to submit transfer %i\n"
|
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"Please increase your allowed "
|
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@ -1938,21 +2070,16 @@ int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
|
||||
if (RTLSDR_CANCELING == dev->async_status) {
|
||||
next_status = RTLSDR_INACTIVE;
|
||||
|
||||
if (!dev->xfer)
|
||||
if (dev->xfer_ctx_list == NULL)
|
||||
break;
|
||||
|
||||
for(i = 0; i < dev->xfer_buf_num; ++i) {
|
||||
if (!dev->xfer[i])
|
||||
for(i = 0; i < dev->xfer_ctx_num; ++i) {
|
||||
if (dev->xfer_ctx_list[i] == NULL)
|
||||
continue;
|
||||
|
||||
if (LIBUSB_TRANSFER_CANCELLED !=
|
||||
dev->xfer[i]->status) {
|
||||
r = libusb_cancel_transfer(dev->xfer[i]);
|
||||
/* handle events after canceling
|
||||
* to allow transfer status to
|
||||
* propagate */
|
||||
libusb_handle_events_timeout_completed(dev->ctx,
|
||||
&zerotv, NULL);
|
||||
rtlsdr_xfer_ctx_status(dev->xfer_ctx_list[i])) {
|
||||
r = rtlsdr_xfer_ctx_cancel(dev->xfer_ctx_list[i]);
|
||||
if (r < 0)
|
||||
continue;
|
||||
|
||||
@ -2054,4 +2181,4 @@ int rtlsdr_set_gpio(rtlsdr_dev_t *dev, int gpio_pin, int on)
|
||||
rtlsdr_set_gpio_bit(dev, gpio_pin, on);
|
||||
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user