mirror of
https://github.com/Cxbx-Reloaded/libusb.git
synced 2025-03-04 07:57:30 +00:00
Linux: Compatibility with new sysfs descriptors file
As of 2.6.26, the descriptors file now includes all descriptors, not just the active one.
This commit is contained in:
Daniel Drake
parent
819e65f880
commit
fbad9a5426
2
TODO
2
TODO
@ -1,5 +1,3 @@
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new sysfs descriptors format
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for 1.1 or future
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==================
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optional timerfd support (runtime detection)
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@ -56,6 +56,10 @@
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*
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* If we also have descriptors, we can obtain the device descriptor and active
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* configuration without touching usbfs at all.
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*
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* The descriptors file originally only contained the active configuration
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* descriptor alongside the device descriptor, but all configurations are
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* included as of Linux 2.6.26.
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*/
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static const char *usbfs_path = NULL;
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@ -262,12 +266,96 @@ static int usbfs_get_active_config_descriptor(struct libusb_device *dev,
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return 0;
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}
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/* read the bConfigurationValue for a device */
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static int sysfs_get_active_config(struct libusb_device *dev, int *config)
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{
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char *endptr;
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char tmp[4] = {0, 0, 0, 0};
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long num;
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int fd;
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size_t r;
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fd = __open_sysfs_attr(dev, "bConfigurationValue");
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if (fd < 0)
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return fd;
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r = read(fd, tmp, sizeof(tmp));
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close(fd);
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if (r < 0) {
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usbi_err(DEVICE_CTX(dev),
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"read bConfigurationValue failed ret=%d errno=%d", r, errno);
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return LIBUSB_ERROR_IO;
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} else if (r == 0) {
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usbi_err(DEVICE_CTX(dev), "device unconfigured");
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*config = -1;
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return 0;
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}
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if (tmp[sizeof(tmp) - 1] != 0) {
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usbi_err(DEVICE_CTX(dev), "not null-terminated?");
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return LIBUSB_ERROR_IO;
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} else if (tmp[0] == 0) {
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usbi_err(DEVICE_CTX(dev), "no configuration value?");
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return LIBUSB_ERROR_IO;
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}
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num = strtol(tmp, &endptr, 10);
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if (endptr == tmp) {
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usbi_err(DEVICE_CTX(dev), "error converting '%s' to integer", tmp);
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return LIBUSB_ERROR_IO;
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}
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*config = (int) num;
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return 0;
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}
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/* takes a usbfs/descriptors fd seeked to the start of a configuration, and
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* seeks to the next one. */
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static int seek_to_next_config(struct libusb_context *ctx, int fd)
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{
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struct libusb_config_descriptor config;
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unsigned char tmp[6];
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off_t off;
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int r;
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/* read first 6 bytes of descriptor */
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r = read(fd, tmp, sizeof(tmp));
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if (r < 0) {
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usbi_err(ctx, "read failed ret=%d errno=%d", r, errno);
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return LIBUSB_ERROR_IO;
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} else if (r < sizeof(tmp)) {
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usbi_err(ctx, "short descriptor read %d/%d", r, sizeof(tmp));
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return LIBUSB_ERROR_IO;
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}
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/* seek forward to end of config */
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usbi_parse_descriptor(tmp, "bbwbb", &config, 1);
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off = lseek(fd, config.wTotalLength - sizeof(tmp), SEEK_CUR);
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if (off < 0) {
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usbi_err(ctx, "seek failed ret=%d errno=%d", off, errno);
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return LIBUSB_ERROR_IO;
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}
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return 0;
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}
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static int sysfs_get_active_config_descriptor(struct libusb_device *dev,
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unsigned char *buffer, size_t len)
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{
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int fd;
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ssize_t r;
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off_t off;
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int to_copy;
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int config;
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unsigned char tmp[6];
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r = sysfs_get_active_config(dev, &config);
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if (r < 0)
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return r;
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if (config == -1)
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return LIBUSB_ERROR_NOT_FOUND;
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usbi_dbg("active configuration %d", config);
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/* sysfs provides access to an in-memory copy of the device descriptor,
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* so we use that rather than keeping our own copy */
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@ -276,6 +364,19 @@ static int sysfs_get_active_config_descriptor(struct libusb_device *dev,
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if (fd < 0)
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return fd;
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/* device might have been unconfigured since we read bConfigurationValue,
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* so first check that there is any config descriptor data at all... */
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off = lseek(fd, 0, SEEK_END);
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if (off < 1) {
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usbi_err(DEVICE_CTX(dev), "end seek failed, ret=%d errno=%d",
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off, errno);
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close(fd);
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return LIBUSB_ERROR_IO;
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} else if (off == DEVICE_DESC_LENGTH) {
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close(fd);
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return LIBUSB_ERROR_NOT_FOUND;
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}
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off = lseek(fd, DEVICE_DESC_LENGTH, SEEK_SET);
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if (off < 0) {
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usbi_err(DEVICE_CTX(dev), "seek failed, ret=%d errno=%d", off, errno);
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@ -283,20 +384,54 @@ static int sysfs_get_active_config_descriptor(struct libusb_device *dev,
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return LIBUSB_ERROR_IO;
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}
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r = read(fd, buffer, len);
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close(fd);
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if (r < 0) {
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usbi_err(DEVICE_CTX(dev), "read failed, ret=%d errno=%d", fd, errno);
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return LIBUSB_ERROR_IO;
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} else if (r == 0) {
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usbi_dbg("device is unconfigured");
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return LIBUSB_ERROR_NOT_FOUND;
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} else if (r < len) {
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usbi_err(DEVICE_CTX(dev), "short read %d/%d", r, len);
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return LIBUSB_ERROR_IO;
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/* unbounded loop: we expect the descriptor to be present under all
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* circumstances */
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while (1) {
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r = read(fd, tmp, sizeof(tmp));
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if (r < 0) {
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usbi_err(DEVICE_CTX(dev), "read failed, ret=%d errno=%d",
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fd, errno);
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return LIBUSB_ERROR_IO;
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} else if (r < sizeof(tmp)) {
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usbi_err(DEVICE_CTX(dev), "short read %d/%d", r, sizeof(tmp));
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return LIBUSB_ERROR_IO;
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}
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/* check bConfigurationValue */
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if (tmp[5] == config)
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break;
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/* try the next descriptor */
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off = lseek(fd, 0 - sizeof(tmp), SEEK_CUR);
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if (off < 0)
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return LIBUSB_ERROR_IO;
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r = seek_to_next_config(DEVICE_CTX(dev), fd);
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if (r < 0)
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return r;
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}
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return 0;
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to_copy = (len < sizeof(tmp)) ? len : sizeof(tmp);
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memcpy(buffer, tmp, to_copy);
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if (len > sizeof(tmp)) {
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r = read(fd, buffer + sizeof(tmp), len - sizeof(tmp));
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if (r < 0) {
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usbi_err(DEVICE_CTX(dev), "read failed, ret=%d errno=%d",
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fd, errno);
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r = LIBUSB_ERROR_IO;
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} else if (r == 0) {
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usbi_dbg("device is unconfigured");
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r = LIBUSB_ERROR_NOT_FOUND;
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} else if (r < len - sizeof(tmp)) {
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usbi_err(DEVICE_CTX(dev), "short read %d/%d", r, len);
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r = LIBUSB_ERROR_IO;
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}
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} else {
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r = 0;
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}
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close(fd);
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return r;
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}
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static int op_get_active_config_descriptor(struct libusb_device *dev,
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@ -310,14 +445,11 @@ static int op_get_active_config_descriptor(struct libusb_device *dev,
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}
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}
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/* takes a usbfs fd, attempts to find the requested config and copy a certain
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* amount of it into an output buffer. a bConfigurationValue of -1 indicates
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* that the first config should be retreived. */
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* amount of it into an output buffer. */
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static int get_config_descriptor(struct libusb_context *ctx, int fd,
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uint8_t config_index, unsigned char *buffer, size_t len)
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{
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unsigned char tmp[8];
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off_t off;
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ssize_t r;
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@ -329,28 +461,10 @@ static int get_config_descriptor(struct libusb_context *ctx, int fd,
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/* might need to skip some configuration descriptors to reach the
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* requested configuration */
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while (config_index) {
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struct libusb_config_descriptor config;
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/* read first 8 bytes of descriptor */
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r = read(fd, tmp, sizeof(tmp));
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if (r < 0) {
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usbi_err(ctx, "read failed ret=%d errno=%d", r, errno);
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return LIBUSB_ERROR_IO;
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} else if (r < sizeof(tmp)) {
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usbi_err(ctx, "short descriptor read %d/%d", r, sizeof(tmp));
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return LIBUSB_ERROR_IO;
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}
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usbi_parse_descriptor(tmp, "bbwbb", &config, 1);
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/* seek forward to end of config */
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off = lseek(fd, config.wTotalLength - sizeof(tmp), SEEK_CUR);
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if (off < 0) {
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usbi_err(ctx, "seek failed ret=%d errno=%d", off, errno);
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return LIBUSB_ERROR_IO;
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}
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while (config_index > 0) {
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r = seek_to_next_config(ctx, fd);
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if (r < 0)
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return r;
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config_index--;
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}
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@ -377,6 +491,10 @@ static int op_get_config_descriptor(struct libusb_device *dev,
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/* always read from usbfs: sysfs only has the active descriptor
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* this will involve waking the device up, but oh well! */
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/* FIXME: the above is no longer true, new kernels have all descriptors
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* in the descriptors file. but its kinda hard to detect if the kernel
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* is sufficiently new. */
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__get_usbfs_path(dev, filename);
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fd = open(filename, O_RDONLY);
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if (fd < 0) {
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@ -438,49 +556,6 @@ static int cache_active_config(struct libusb_device *dev, int fd,
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return 0;
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}
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/* read the bConfigurationValue for a device */
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static int sysfs_get_active_config(struct libusb_device *dev, int *config)
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{
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char *endptr;
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char tmp[4] = {0, 0, 0, 0};
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long num;
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int fd;
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size_t r;
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fd = __open_sysfs_attr(dev, "bConfigurationValue");
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if (fd < 0)
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return fd;
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r = read(fd, tmp, sizeof(tmp));
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close(fd);
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if (r < 0) {
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usbi_err(DEVICE_CTX(dev),
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"read bConfigurationValue failed ret=%d errno=%d", r, errno);
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return LIBUSB_ERROR_IO;
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} else if (r == 0) {
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usbi_err(DEVICE_CTX(dev), "device unconfigured");
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*config = -1;
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return 0;
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}
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if (tmp[sizeof(tmp) - 1] != 0) {
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usbi_err(DEVICE_CTX(dev), "not null-terminated?");
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return LIBUSB_ERROR_IO;
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} else if (tmp[0] == 0) {
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usbi_err(DEVICE_CTX(dev), "no configuration value?");
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return LIBUSB_ERROR_IO;
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}
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num = strtol(tmp, &endptr, 10);
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if (endptr == tmp) {
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usbi_err(DEVICE_CTX(dev), "error converting '%s' to integer", tmp);
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return LIBUSB_ERROR_IO;
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}
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*config = (int) num;
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return 0;
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}
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/* send a control message to retrieve active configuration */
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static int usbfs_get_active_config(struct libusb_device *dev, int fd)
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{
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