Add BTF tests

Adding BTF test to clang_parser modules with generated BTF data.
bpftrace · Jul 29, 2019 · 1d46b50 · 1d46b50
1 parent 1df787d
commit 1d46b50
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Showing 4 changed files with 218 additions and 2 deletions.
diff --git a/src/btf.cpp b/src/btf.cpp
@@ -36,11 +36,89 @@ static int libbpf_print(enum libbpf_print_level level, const char *msg, va_list
   return vfprintf(stderr, msg, ap);
 }
 
+static unsigned char *get_data(const char *file, ssize_t *sizep)
+{
+  ssize_t ret;
+  int fd;
+
+  fd = open(file, O_RDONLY);
+  if (fd < 0)
+    return NULL;
+
+  struct stat st;
+
+  if (fstat(fd, &st))
+  {
+    close(fd);
+    return NULL;
+  }
+
+  unsigned char *data;
+  unsigned int size;
+
+  size = st.st_size;
+
+  data = (unsigned char *) malloc(size);
+  if (!data)
+  {
+    close(fd);
+    return NULL;
+  }
+
+  ret = read(fd, data, size);
+  if (ret <= 0)
+  {
+    close(fd);
+    free(data);
+    return NULL;
+  }
+
+  close(fd);
+
+  *sizep = size;
+  return data;
+}
+
+void BTF::init_test(char *file)
+{
+  unsigned char *data;
+  ssize_t size;
+
+  data = get_data(file, &size);
+  if (data == NULL)
+  {
+    std::cerr << "BTF: failed to read data from: " << file << std::endl;
+    btf = NULL;
+    return;
+  }
+
+  btf = btf__new(data, (__u32) size);
+  if (IS_ERR(btf))
+  {
+    std::cerr << "BTF: failed to initialize data" << std::endl;
+    btf = NULL;
+  }
+  else
+  {
+    libbpf_set_print(libbpf_print);
+    state = OK;
+  }
+  free(data);
+}
+
 BTF::BTF(void) : btf(NULL), state(NODATA)
 {
   struct utsname uts;
   char *path;
 
+  // Try to get BTF file from BPFTRACE_BTF_TEST env
+  path = std::getenv("BPFTRACE_BTF_TEST");
+  if (path)
+  {
+    init_test(path);
+    return;
+  }
+
   if (uname(&uts))
   {
     std::cerr << "BTF: failed to get uname" << std::endl;

diff --git a/src/btf.h b/src/btf.h
@@ -22,6 +22,8 @@ class BTF
   std::string c_def(std::string& name);
 
 private:
+  void init_test(char *file);
+
   struct btf *btf;
   enum state state = NODATA;
 };

diff --git a/tests/btf_data.h b/tests/btf_data.h
@@ -0,0 +1,48 @@
+#pragma once
+
+#if 0
+The data consists of following source file objects:
+
+       struct Foo1 {
+         int  a;
+         char b;
+         long c;
+       };
+
+       struct Foo2 {
+         int         a;
+         struct Foo1 f;
+       };
+
+       struct Foo3 {
+         struct Foo1 *foo1;
+         struct Foo2 *foo2;
+       };
+#endif
+
+unsigned char btf_data[] = {
+  0x9f, 0xeb, 0x01, 0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0xc0, 0x00, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x34, 0x00, 0x00, 0x00,
+  0x01, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x04, 0x10, 0x00, 0x00, 0x00,
+  0x10, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x12, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00,
+  0x14, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,
+  0x27, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x04, 0x00, 0x00, 0x00,
+  0x20, 0x00, 0x00, 0x01, 0x16, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+  0x01, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x2b, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x01, 0x08, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x01,
+  0x06, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x04, 0x18, 0x00, 0x00, 0x00,
+  0x10, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x1b, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,
+  0x0b, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x04, 0x10, 0x00, 0x00, 0x00,
+  0x1d, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x22, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x01, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x05, 0x00, 0x00, 0x00,
+  0x00, 0x46, 0x6f, 0x6f, 0x31, 0x00, 0x46, 0x6f, 0x6f, 0x32, 0x00, 0x46,
+  0x6f, 0x6f, 0x33, 0x00, 0x61, 0x00, 0x62, 0x00, 0x63, 0x00, 0x63, 0x68,
+  0x61, 0x72, 0x00, 0x66, 0x00, 0x66, 0x6f, 0x6f, 0x31, 0x00, 0x66, 0x6f,
+  0x6f, 0x32, 0x00, 0x69, 0x6e, 0x74, 0x00, 0x6c, 0x6f, 0x6e, 0x67, 0x20,
+  0x69, 0x6e, 0x74, 0x00
+};
+unsigned int btf_data_len = 268;
diff --git a/tests/clang_parser.cpp b/tests/clang_parser.cpp
@@ -10,9 +10,10 @@ namespace clang_parser {
 
 using StructMap = std::map<std::string, Struct>;
 
-static void parse(const std::string &input, BPFtrace &bpftrace, bool result = true)
+static void parse(const std::string &input, BPFtrace &bpftrace, bool result = true,
+                  const std::string& probe = "kprobe:sys_read { 1 }")
 {
-  auto extended_input = input + "kprobe:sys_read { 1 }";
+  auto extended_input = input + probe;
   Driver driver(bpftrace);
   ASSERT_EQ(driver.parse_str(extended_input), 0);
 
@@ -380,6 +381,93 @@ TEST(clang_parser, parse_fail)
   parse("struct a { int a; struct b b; };", bpftrace, false);
 }
 
+#ifdef HAVE_LIBBPF_BTF_DUMP
+
+#include "btf_data.h"
+
+TEST(clang_parser, btf)
+{
+  char *path = strdup("/tmp/XXXXXX");
+  ASSERT_TRUE(path != NULL);
+
+  int fd = mkstemp(path);
+  ASSERT_TRUE(fd >= 0);
+
+  EXPECT_EQ(write(fd, btf_data, btf_data_len), btf_data_len);
+  close(fd);
+
+  ASSERT_EQ(setenv("BPFTRACE_BTF_TEST", path, true), 0);
+
+  BPFtrace bpftrace;
+  parse("", bpftrace, true,
+        "kprobe:sys_read {\n"
+        "  @x1 = (struct Foo1 *) curtask;\n"
+        "  @x2 = (struct Foo2 *) curtask;\n"
+        "  @x3 = (struct Foo3 *) curtask;\n"
+        "}");
+
+  // clear the environment
+  unsetenv("BPFTRACE_BTF_TEST");
+  std::remove(path);
+
+  StructMap &structs = bpftrace.structs_;
+
+  ASSERT_EQ(structs.size(), 3U);
+  ASSERT_EQ(structs.count("Foo1"), 1U);
+  ASSERT_EQ(structs.count("Foo2"), 1U);
+  ASSERT_EQ(structs.count("Foo3"), 1U);
+
+  EXPECT_EQ(structs["Foo1"].size, 16);
+  ASSERT_EQ(structs["Foo1"].fields.size(), 3U);
+  ASSERT_EQ(structs["Foo1"].fields.count("a"), 1U);
+  ASSERT_EQ(structs["Foo1"].fields.count("b"), 1U);
+  ASSERT_EQ(structs["Foo1"].fields.count("c"), 1U);
+
+  EXPECT_EQ(structs["Foo1"].fields["a"].type.type, Type::integer);
+  EXPECT_EQ(structs["Foo1"].fields["a"].type.size, 4U);
+  EXPECT_EQ(structs["Foo1"].fields["a"].offset, 0);
+
+  EXPECT_EQ(structs["Foo1"].fields["b"].type.type, Type::integer);
+  EXPECT_EQ(structs["Foo1"].fields["b"].type.size, 1U);
+  EXPECT_EQ(structs["Foo1"].fields["b"].offset, 4);
+
+  EXPECT_EQ(structs["Foo1"].fields["c"].type.type, Type::integer);
+  EXPECT_EQ(structs["Foo1"].fields["c"].type.size, 8U);
+  EXPECT_EQ(structs["Foo1"].fields["c"].offset, 8);
+
+  EXPECT_EQ(structs["Foo2"].size, 24);
+  ASSERT_EQ(structs["Foo2"].fields.size(), 2U);
+  ASSERT_EQ(structs["Foo2"].fields.count("a"), 1U);
+  ASSERT_EQ(structs["Foo2"].fields.count("f"), 1U);
+
+  EXPECT_EQ(structs["Foo2"].fields["a"].type.type, Type::integer);
+  EXPECT_EQ(structs["Foo2"].fields["a"].type.size, 4U);
+  EXPECT_EQ(structs["Foo2"].fields["a"].offset, 0);
+
+  EXPECT_EQ(structs["Foo2"].fields["f"].type.type, Type::cast);
+  EXPECT_EQ(structs["Foo2"].fields["f"].type.size, 16U);
+  EXPECT_EQ(structs["Foo2"].fields["f"].offset, 8);
+
+  EXPECT_EQ(structs["Foo3"].size, 16);
+  ASSERT_EQ(structs["Foo3"].fields.size(), 2U);
+  ASSERT_EQ(structs["Foo3"].fields.count("foo1"), 1U);
+  ASSERT_EQ(structs["Foo3"].fields.count("foo2"), 1U);
+
+  EXPECT_EQ(structs["Foo3"].fields["foo1"].type.type, Type::cast);
+  EXPECT_EQ(structs["Foo3"].fields["foo1"].type.size, 8U);
+  EXPECT_EQ(structs["Foo3"].fields["foo1"].type.is_pointer, true);
+  EXPECT_EQ(structs["Foo3"].fields["foo1"].type.cast_type, "Foo1");
+  EXPECT_EQ(structs["Foo3"].fields["foo1"].offset, 0);
+
+  EXPECT_EQ(structs["Foo3"].fields["foo2"].type.type, Type::cast);
+  EXPECT_EQ(structs["Foo3"].fields["foo2"].type.size, 8U);
+  EXPECT_EQ(structs["Foo3"].fields["foo2"].type.is_pointer, true);
+  EXPECT_EQ(structs["Foo3"].fields["foo2"].type.cast_type, "Foo2");
+  EXPECT_EQ(structs["Foo3"].fields["foo2"].offset, 8);
+}
+
+#endif // HAVE_LIBBPF_BTF_DUMP
+
 } // namespace clang_parser
 } // namespace test
 } // namespace bpftrace