Add Platform_getProcessEnv

- currently implemented for darwin and linux

darwin/Platform.c

@@ -236,3 +236,56 @@ void Platform_setSwapValues(Meter* mtr) {
   mtr->total = swapused.xsu_total / 1024;
   mtr->values[0] = swapused.xsu_used / 1024;
 }
+
+char* Platform_getProcessEnv(pid_t pid) {
+   char* env = NULL;
+
+   int argmax;
+   size_t bufsz = sizeof(argmax);
+
+   int mib[3];
+   mib[0] = CTL_KERN;
+   mib[1] = KERN_ARGMAX;
+   if (sysctl(mib, 2, &argmax, &bufsz, 0, 0) == 0) {
+      char* buf = malloc(argmax);
+      if (buf) {
+         mib[0] = CTL_KERN;
+         mib[1] = KERN_PROCARGS2;
+         mib[2] = pid;
+         size_t bufsz = argmax;
+         if (sysctl(mib, 3, buf, &bufsz, 0, 0) == 0) {
+            if (bufsz > sizeof(int)) {
+               char *p = buf, *endp = buf + bufsz;
+               int argc = *(int*)p;
+               p += sizeof(int);
+
+               // skip exe
+               p = strchr(p, 0)+1;
+
+               // skip padding
+               while(!*p && p < endp)
+                  ++p;
+
+               // skip argv
+               for (; argc-- && p < endp; p = strrchr(p, 0)+1)
+                  ;
+
+               // skip padding
+               while(!*p && p < endp)
+                  ++p;
+
+               size_t size = endp - p;
+               env = malloc(size+2);
+               if (env) {
+                  memcpy(env, p, size);
+                  env[size] = 0;
+                  env[size+1] = 0;
+               }
+            }
+         }
+         free(buf);
+      }
+   }
+
+   return env;
+}

darwin/Platform.h

@@ -44,4 +44,6 @@ void Platform_setMemoryValues(Meter* mtr);
 
 void Platform_setSwapValues(Meter* mtr);
 
+char* Platform_getProcessEnv(pid_t pid);
+
 #endif