Trying to get BCC cpp to work

ratemon/runtime/iter_map.cc

@@ -0,0 +1,97 @@
+
+#include <unistd.h>
+
+#include <fstream>
+#include <iostream>
+#include <string>
+
+#include "BPF.h"
+#include "bcc_version.h"
+
+const std::string BPF_PROGRAM = R"(
+#include <linux/bpf.h>
+
+BPF_TABLE_PINNED("hash", u32, u32, test_map, 1024, "/sys/fs/bpf/test_map");
+
+BPF_ITER(bpf_map_elem) {
+  struct bpf_map *map = ctx->map;
+  u32 *key = ctx->key;
+  u32 *val = ctx->value;
+  if (key == (void *)0 || val == (void *)0) return 0;
+  bpf_trace_printk("Iterating %d %d\n", key, val);
+  return 0;
+}
+)";
+
+int main() {
+  ebpf::BPF bpf;
+  auto res = bpf.init(BPF_PROGRAM);
+  if (!res.ok()) {
+    std::cerr << res.msg() << std::endl;
+    return 1;
+  }
+
+  int prog_fd;
+  res = bpf.load_func("bpf_iter__bpf_map_elem", BPF_PROG_TYPE_TRACING, prog_fd);
+  if (!res.ok()) {
+    std::cerr << res.msg() << std::endl;
+    return 1;
+  }
+  std::cerr << "prog_fd: " << prog_fd << std::endl;
+
+  int link_fd = bcc_iter_attach(prog_fd, NULL, 0);
+  if (link_fd < 0) {
+    std::cerr << "bcc_iter_attach failed: " << link_fd << std::endl;
+    switch (link_fd) {
+    case -ENOMSG:
+      std::cerr << "ENOMSG " << link_fd << std::endl;
+      break;
+    case -EINVAL:
+      std::cerr << "EINVAL " << link_fd << std::endl;
+      break;
+    case -ENOENT:
+      std::cerr << "ENOENT " << link_fd << std::endl;
+      break;
+    case -ENOSPC:
+      std::cerr << "ENOSPC " << link_fd << std::endl;
+      break;
+    case -EFAULT:
+      std::cerr << "EFAULT " << link_fd << std::endl;
+      break;
+    case -EPERM:
+      std::cerr << "EPERM " << link_fd << std::endl;
+      break;
+    case -EAGAIN:
+      std::cerr << "EAGAIN " << link_fd << std::endl;
+      break;
+    case -EBADF:
+      std::cerr << "EBADF " << link_fd << std::endl;
+      break;
+    default:
+      std::cerr << "unknown " << link_fd << std::endl;
+    }
+    return 1;
+  }
+
+  int iter_fd = bcc_iter_create(link_fd);
+  if (iter_fd < 0) {
+    std::cerr << "bcc_iter_create failed: " << iter_fd << std::endl;
+    close(link_fd);
+    return 1;
+  }
+
+  int len = 0;
+  uint32_t dest = 0;
+  while ((len = read(iter_fd, (char *)&dest, sizeof(dest)))) {
+    if (len < 0) {
+      if (len == -EAGAIN)
+        continue;
+      std::cerr << "read failed: " << len << std::endl;
+      break;
+    }
+  }
+
+  close(iter_fd);
+  close(link_fd);
+  return 0;
+}