Function logicalProcessorsFromProcCPUInfo

pkg/cpu/cpu_linux.go:350–409

logicalProcessorsFromProcCPUInfo reads the `/proc/cpuinfo` pseudofile and returns a map, keyed by logical processor ID, of logical processor structs. `/proc/cpuinfo` files look like the following: ``` processor : 0 vendor_id : AuthenticAMD cpu family : 23 model : 8 model name : AMD Ryzen 7 2700X

(
	ctx context.Context,
)

// with blank line-separated blocks of colon-delimited attribute name/value
// pairs for a specific logical processor on the host.
func logicalProcessorsFromProcCPUInfo(
	ctx context.Context,
) map[int]*logicalProcessor {
	paths := linuxpath.New(ctx)
	r, err := os.Open(paths.ProcCpuinfo)
	if err != nil {
		return nil
	}
	defer util.SafeClose(r)

	lps := map[int]*logicalProcessor{}

	// A map of attributes describing the logical processor
	lpAttrs := map[string]string{}

	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			// Output of /proc/cpuinfo has a blank newline to separate logical
			// processors, so here we collect up all the attributes we've
			// collected for this logical processor block
			// s390x identifies CPUs via "cpu number", while most other
			// architectures use "processor".
			idStr, ok := lpAttrs["processor"]
			if !ok {
				idStr, ok = lpAttrs["cpu number"]
			}

			if ok {
				id, _ := strconv.Atoi(idStr)
				lps[id] = &logicalProcessor{
					ID:    id,
					Attrs: lpAttrs,
				}
				// Only reset attributes after a valid processor block is saved.
				// This ensures that shared header metadata (like vendor_id on s390x)
				// is carried over and available to the processor entries.
				lpAttrs = map[string]string{}
			} else if len(lpAttrs) > 0 {
				// s390x header check: if we have 'vendor_id' but no 'processor' ID,
				// it's the summary block. We don't warn and we don't reset lpAttrs
				// so the vendor_id carries over to the first actual CPU block.
				if _, isS390Header := lpAttrs["vendor_id"]; !isS390Header {
					log.Warn(ctx,
						"expected to find 'processor' or 'cpu number' key "+
							"in /proc/cpuinfo attributes")
				}
			}
			continue
		}
		parts := strings.SplitN(line, ":", 2)
		if len(parts) >= 2 {
			key := strings.TrimSpace(parts[0])
			value := strings.TrimSpace(parts[1])
			lpAttrs[key] = value
		}
	}