Improve computer model detection when device tree is not available

Closes mvp#614.

Author: mvp

uhubctl.c

@@ -396,15 +396,39 @@ static int ports2bitmap(char* const portlist)
 static int get_computer_model(char *model, int len)
 {
  int fd = open("/sys/firmware/devicetree/base/model", O_RDONLY);
- if (fd < 0) {
- return fd;
- }
- int bytes_read = read(fd, model, len-1);
- close(fd);
- if (bytes_read < 0) {
- return -1;
+ if (fd >= 0) {
+ int bytes_read = read(fd, model, len-1);
+ close(fd);
+ if (bytes_read < 0) {
+ return -1;
+ }
+ model[bytes_read] = 0;
+ } else {
+ // devicetree is not available, try parsing /proc/cpuinfo instead.
+ // most Raspberry Pi have /proc/cpuinfo about 1KB, so 4KB buffer should be plenty:
+ char buffer[4096] = {0}; // fill buffer with all zeros
+ fd = open("/proc/cpuinfo", O_RDONLY);
+ if (fd < 0) {
+ return -1;
+ }
+ int bytes_read = read(fd, buffer, sizeof(buffer)-1);
+ close(fd);
+ if (bytes_read < 0) {
+ return -1;
+ }
+ buffer[bytes_read] = 0;
+ char* model_start = strstr(buffer, "Model\t\t: ");
+ if (model_start == NULL) {
+ return -1;
+ }
+ char* model_name = model_start + 9;
+ char* newline_pos = strchr(model_name, '\n');
+ if (newline_pos != NULL) {
+ *newline_pos = 0;
+ }
+ strncpy(model, model_name, len);
+ model[len-1] = 0;
  }
- model[bytes_read] = 0;
  return 0;
 }