Add util function to read USB descriptor string

Use it from accept_device() to simplify (at the cost an additional
allocation for each serial, but it is not important).

It will also be useful in other functions in further commits.

PR #2974 <https://github.com/Genymobile/scrcpy/pull/2974>
This commit is contained in:
Romain Vimont 2022-01-25 19:40:51 +01:00
parent bbef426a4b
commit 1ab3692f3d

View file

@ -9,6 +9,26 @@ log_libusb_error(enum libusb_error errcode) {
LOGW("libusb error: %s", libusb_strerror(errcode)); LOGW("libusb error: %s", libusb_strerror(errcode));
} }
static char *
read_string(libusb_device_handle *handle, uint8_t desc_index) {
char buffer[128];
int result =
libusb_get_string_descriptor_ascii(handle, desc_index,
(unsigned char *) buffer,
sizeof(buffer));
if (result < 0) {
return NULL;
}
assert((size_t) result <= sizeof(buffer));
// When non-negative, 'result' contains the number of bytes written
char *s = malloc(result + 1);
memcpy(s, buffer, result);
s[result] = '\0';
return s;
}
static bool static bool
accept_device(libusb_device *device, const char *serial) { accept_device(libusb_device *device, const char *serial) {
// Do not log any USB error in this function, it is expected that many USB // Do not log any USB error in this function, it is expected that many USB
@ -26,19 +46,15 @@ accept_device(libusb_device *device, const char *serial) {
return false; return false;
} }
char buffer[128]; char *device_serial = read_string(handle, desc.iSerialNumber);
result = libusb_get_string_descriptor_ascii(handle, desc.iSerialNumber,
(unsigned char *) buffer,
sizeof(buffer));
libusb_close(handle); libusb_close(handle);
if (result < 0) { if (!device_serial) {
return false; return false;
} }
buffer[sizeof(buffer) - 1] = '\0'; // just in case bool matches = !strcmp(serial, device_serial);
free(device_serial);
// Accept the device if its serial matches return matches;
return !strcmp(buffer, serial);
} }
static libusb_device * static libusb_device *