Processes: adds total thread count detection

src/detection/processes/processes_linux.c

@@ -1,27 +1,60 @@
 #include "processes.h"
 
 #include "common/io.h"
+#include "common/memrchr.h"
 #include "common/strutil.h"
 
-const char* ffDetectProcesses(uint32_t* result) {
+const char* ffDetectProcesses(FFProcessesResult* result) {
     FF_AUTO_CLOSE_DIR DIR* dir = opendir("/proc");
     if (dir == nullptr) {
         return "opendir(\"/proc\") failed";
     }
 
-    uint32_t num = 0;
+    uint32_t processes = 0;
+    uint32_t threads = 0;
+
+    int procfd = dirfd(dir);
 
     struct dirent* entry;
     while ((entry = readdir(dir)) != nullptr) {
-        if (
-#ifdef _DIRENT_HAVE_D_TYPE
-            (entry->d_type == DT_DIR || entry->d_type == DT_UNKNOWN) &&
-#endif
-            ffCharIsDigit(entry->d_name[0]))
-            ++num;
+        if ((entry->d_type == DT_DIR || entry->d_type == DT_UNKNOWN) && ffCharIsDigit(entry->d_name[0])) {
+            ++processes;
+
+            char statPath[32];
+            strcpy(ffStrCopy(statPath, entry->d_name, sizeof(statPath)), "/stat");
+
+            char statBuffer[256];
+            ssize_t statLength = ffReadFileDataRelative(procfd, statPath, sizeof(statBuffer) - 1, statBuffer);
+            if (statLength < 0) {
+                continue;
+            }
+            statBuffer[statLength] = '\0';
+
+            const char* cursor = (const char*) memrchr(statBuffer, ')', (size_t) statLength);
+            if (!cursor) {
+                continue;
+            }
+            ++cursor;
+
+            for (uint32_t field = 2 /*comm*/; field < 20 /*num_threads*/; ++field) {
+                while (*cursor != ' ' && __builtin_expect(*cursor != '\0', true)) {
+                    ++cursor;
+                }
+                ++cursor;
+                if (__builtin_expect(*cursor == '\0', false)) {
+                    break;
+                }
+            }
+            if (__builtin_expect(*cursor == '\0', false)) {
+                continue;
+            }
+
+            threads += (uint32_t) strtoul(cursor, nullptr, 10);
+        }
     }
 
-    *result = num;
+    result->processes = processes;
+    result->threads = threads;
 
     return nullptr;
 }