selftests/bpf: add btf_dump BTF-to-C conversion tests
authorAndrii Nakryiko <andriin@fb.com>
Fri, 24 May 2019 18:59:04 +0000 (11:59 -0700)
committerAlexei Starovoitov <ast@kernel.org>
Fri, 24 May 2019 21:05:58 +0000 (14:05 -0700)
Add new test_btf_dump set of tests, validating BTF-to-C conversion
correctness. Tests rely on clang to generate BTF from provided C test
cases.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
tools/testing/selftests/bpf/.gitignore
tools/testing/selftests/bpf/Makefile
tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/btf_dump_test_case_multidim.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/btf_dump_test_case_ordering.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c [new file with mode: 0644]
tools/testing/selftests/bpf/test_btf_dump.c [new file with mode: 0644]

index 138b6c0..b3da2ff 100644 (file)
@@ -36,3 +36,4 @@ alu32
 libbpf.pc
 libbpf.so.*
 test_hashmap
+test_btf_dump
index ddae064..cd23758 100644 (file)
@@ -23,7 +23,8 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
        test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
        test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user \
        test_socket_cookie test_cgroup_storage test_select_reuseport test_section_names \
-       test_netcnt test_tcpnotify_user test_sock_fields test_sysctl test_hashmap
+       test_netcnt test_tcpnotify_user test_sock_fields test_sysctl test_hashmap \
+       test_btf_dump
 
 BPF_OBJ_FILES = $(patsubst %.c,%.o, $(notdir $(wildcard progs/*.c)))
 TEST_GEN_FILES = $(BPF_OBJ_FILES)
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c
new file mode 100644 (file)
index 0000000..8f44767
--- /dev/null
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper tests for bitfield.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+#include <stdbool.h>
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct bitfields_only_mixed_types {
+ *     int a: 3;
+ *     long int b: 2;
+ *     _Bool c: 1;
+ *     enum {
+ *             A = 0,
+ *             B = 1,
+ *     } d: 1;
+ *     short e: 5;
+ *     int: 20;
+ *     unsigned int f: 30;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+struct bitfields_only_mixed_types {
+       int a: 3;
+       long int b: 2;
+       bool c: 1; /* it's really a _Bool type */
+       enum {
+               A, /* A = 0, dumper is very explicit */
+               B, /* B = 1, same */
+       } d: 1;
+       short e: 5;
+       /* 20-bit padding here */
+       unsigned f: 30; /* this gets aligned on 4-byte boundary */
+};
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct bitfield_mixed_with_others {
+ *     char: 4;
+ *     int a: 4;
+ *     short b;
+ *     long int c;
+ *     long int d: 8;
+ *     int e;
+ *     int f;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+struct bitfield_mixed_with_others {
+       long: 4; /* char is enough as a backing field */
+       int a: 4;
+       /* 8-bit implicit padding */
+       short b; /* combined with previous bitfield */
+       /* 4 more bytes of implicit padding */
+       long c;
+       long d: 8;
+       /* 24 bits implicit padding */
+       int e; /* combined with previous bitfield */
+       int f;
+       /* 4 bytes of padding */
+};
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct bitfield_flushed {
+ *     int a: 4;
+ *     long: 60;
+ *     long int b: 16;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+struct bitfield_flushed {
+       int a: 4;
+       long: 0; /* flush until next natural alignment boundary */
+       long b: 16;
+};
+
+int f(struct {
+       struct bitfields_only_mixed_types _1;
+       struct bitfield_mixed_with_others _2;
+       struct bitfield_flushed _3;
+} *_)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_multidim.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_multidim.c
new file mode 100644 (file)
index 0000000..ba97165
--- /dev/null
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper test for multi-dimensional array output.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+typedef int arr_t[2];
+
+typedef int multiarr_t[3][4][5];
+
+typedef int *ptr_arr_t[6];
+
+typedef int *ptr_multiarr_t[7][8][9][10];
+
+typedef int * (*fn_ptr_arr_t[11])();
+
+typedef int * (*fn_ptr_multiarr_t[12][13])();
+
+struct root_struct {
+       arr_t _1;
+       multiarr_t _2;
+       ptr_arr_t _3;
+       ptr_multiarr_t _4;
+       fn_ptr_arr_t _5;
+       fn_ptr_multiarr_t _6;
+};
+
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+int f(struct root_struct *s)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c
new file mode 100644 (file)
index 0000000..92a4ad4
--- /dev/null
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper test validating no name versioning happens between
+ * independent C namespaces (struct/union/enum vs typedef/enum values).
+ *
+ * Copyright (c) 2019 Facebook
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+struct S {
+       int S;
+       int U;
+};
+
+typedef struct S S;
+
+union U {
+       int S;
+       int U;
+};
+
+typedef union U U;
+
+enum E {
+       V = 0,
+};
+
+typedef enum E E;
+
+struct A {};
+
+union B {};
+
+enum C {
+       A = 1,
+       B = 2,
+       C = 3,
+};
+
+struct X {};
+
+union Y {};
+
+enum Z;
+
+typedef int X;
+
+typedef int Y;
+
+typedef int Z;
+
+/*------ END-EXPECTED-OUTPUT ------ */
+
+int f(struct {
+       struct S _1;
+       S _2;
+       union U _3;
+       U _4;
+       enum E _5;
+       E _6;
+       struct A a;
+       union B b;
+       enum C c;
+       struct X x;
+       union Y y;
+       enum Z *z;
+       X xx;
+       Y yy;
+       Z zz;
+} *_)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_ordering.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_ordering.c
new file mode 100644 (file)
index 0000000..7c95702
--- /dev/null
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper test for topological sorting of dependent structs.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+struct s1 {};
+
+struct s3;
+
+struct s4;
+
+struct s2 {
+       struct s2 *s2;
+       struct s3 *s3;
+       struct s4 *s4;
+};
+
+struct s3 {
+       struct s1 s1;
+       struct s2 s2;
+};
+
+struct s4 {
+       struct s1 s1;
+       struct s3 s3;
+};
+
+struct list_head {
+       struct list_head *next;
+       struct list_head *prev;
+};
+
+struct hlist_node {
+       struct hlist_node *next;
+       struct hlist_node **pprev;
+};
+
+struct hlist_head {
+       struct hlist_node *first;
+};
+
+struct callback_head {
+       struct callback_head *next;
+       void (*func)(struct callback_head *);
+};
+
+struct root_struct {
+       struct s4 s4;
+       struct list_head l;
+       struct hlist_node n;
+       struct hlist_head h;
+       struct callback_head cb;
+};
+
+/*------ END-EXPECTED-OUTPUT ------ */
+
+int f(struct root_struct *root)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c
new file mode 100644 (file)
index 0000000..1cef3be
--- /dev/null
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper tests for struct packing determination.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+struct packed_trailing_space {
+       int a;
+       short b;
+} __attribute__((packed));
+
+struct non_packed_trailing_space {
+       int a;
+       short b;
+};
+
+struct packed_fields {
+       short a;
+       int b;
+} __attribute__((packed));
+
+struct non_packed_fields {
+       short a;
+       int b;
+};
+
+struct nested_packed {
+       char: 4;
+       int a: 4;
+       long int b;
+       struct {
+               char c;
+               int d;
+       } __attribute__((packed)) e;
+} __attribute__((packed));
+
+union union_is_never_packed {
+       int a: 4;
+       char b;
+       char c: 1;
+};
+
+union union_does_not_need_packing {
+       struct {
+               long int a;
+               int b;
+       } __attribute__((packed));
+       int c;
+};
+
+union jump_code_union {
+       char code[5];
+       struct {
+               char jump;
+               int offset;
+       } __attribute__((packed));
+};
+
+/*------ END-EXPECTED-OUTPUT ------ */
+
+int f(struct {
+       struct packed_trailing_space _1;
+       struct non_packed_trailing_space _2;
+       struct packed_fields _3;
+       struct non_packed_fields _4;
+       struct nested_packed _5;
+       union union_is_never_packed _6;
+       union union_does_not_need_packing _7;
+       union jump_code_union _8;
+} *_)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c
new file mode 100644 (file)
index 0000000..3a62119
--- /dev/null
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper tests for implicit and explicit padding between fields and
+ * at the end of a struct.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+struct padded_implicitly {
+       int a;
+       long int b;
+       char c;
+};
+
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct padded_explicitly {
+ *     int a;
+ *     int: 32;
+ *     int b;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+struct padded_explicitly {
+       int a;
+       int: 1; /* algo will explicitly pad with full 32 bits here */
+       int b;
+};
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct padded_a_lot {
+ *     int a;
+ *     long: 32;
+ *     long: 64;
+ *     long: 64;
+ *     int b;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+struct padded_a_lot {
+       int a;
+       /* 32 bit of implicit padding here, which algo will make explicit */
+       long: 64;
+       long: 64;
+       int b;
+};
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct padded_cache_line {
+ *     int a;
+ *     long: 32;
+ *     long: 64;
+ *     long: 64;
+ *     long: 64;
+ *     int b;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+struct padded_cache_line {
+       int a;
+       int b __attribute__((aligned(32)));
+};
+
+/* ----- START-EXPECTED-OUTPUT ----- */
+/*
+ *struct zone_padding {
+ *     char x[0];
+ *};
+ *
+ *struct zone {
+ *     int a;
+ *     short b;
+ *     short: 16;
+ *     struct zone_padding __pad__;
+ *};
+ *
+ */
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+struct zone_padding {
+       char x[0];
+} __attribute__((__aligned__(8)));
+
+struct zone {
+       int a;
+       short b;
+       short: 16;
+       struct zone_padding __pad__;
+};
+
+int f(struct {
+       struct padded_implicitly _1;
+       struct padded_explicitly _2;
+       struct padded_a_lot _3;
+       struct padded_cache_line _4;
+       struct zone _5;
+} *_)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
new file mode 100644 (file)
index 0000000..d4a02fe
--- /dev/null
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C dumper test for majority of C syntax quirks.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+enum e1 {
+       A = 0,
+       B = 1,
+};
+
+enum e2 {
+       C = 100,
+       D = -100,
+       E = 0,
+};
+
+typedef enum e2 e2_t;
+
+typedef enum {
+       F = 0,
+       G = 1,
+       H = 2,
+} e3_t;
+
+typedef int int_t;
+
+typedef volatile const int * volatile const crazy_ptr_t;
+
+typedef int *****we_need_to_go_deeper_ptr_t;
+
+typedef volatile const we_need_to_go_deeper_ptr_t * restrict * volatile * const * restrict volatile * restrict const * volatile const * restrict volatile const how_about_this_ptr_t;
+
+typedef int *ptr_arr_t[10];
+
+typedef void (*fn_ptr1_t)(int);
+
+typedef void (*printf_fn_t)(const char *, ...);
+
+/* ------ END-EXPECTED-OUTPUT ------ */
+/*
+ * While previous function pointers are pretty trivial (C-syntax-level
+ * trivial), the following are deciphered here for future generations:
+ *
+ * - `fn_ptr2_t`: function, taking anonymous struct as a first arg and pointer
+ *   to a function, that takes int and returns int, as a second arg; returning
+ *   a pointer to a const pointer to a char. Equivalent to:
+ *     typedef struct { int a; } s_t;
+ *     typedef int (*fn_t)(int);
+ *     typedef char * const * (*fn_ptr2_t)(s_t, fn_t);
+ *
+ * - `fn_complext_t`: pointer to a function returning struct and accepting
+ *   union and struct. All structs and enum are anonymous and defined inline.
+ *
+ * - `signal_t: pointer to a function accepting a pointer to a function as an
+ *   argument and returning pointer to a function as a result. Sane equivalent:
+ *     typedef void (*signal_handler_t)(int);
+ *     typedef signal_handler_t (*signal_ptr_t)(int, signal_handler_t);
+ *
+ * - fn_ptr_arr1_t: array of pointers to a function accepting pointer to
+ *   a pointer to an int and returning pointer to a char. Easy.
+ *
+ * - fn_ptr_arr2_t: array of const pointers to a function taking no arguments
+ *   and returning a const pointer to a function, that takes pointer to a
+ *   `int -> char *` function and returns pointer to a char. Equivalent:
+ *   typedef char * (*fn_input_t)(int);
+ *   typedef char * (*fn_output_outer_t)(fn_input_t);
+ *   typedef const fn_output_outer_t (* fn_output_inner_t)();
+ *   typedef const fn_output_inner_t fn_ptr_arr2_t[5];
+ */
+/* ----- START-EXPECTED-OUTPUT ----- */
+typedef char * const * (*fn_ptr2_t)(struct {
+       int a;
+}, int (*)(int));
+
+typedef struct {
+       int a;
+       void (*b)(int, struct {
+               int c;
+       }, union {
+               char d;
+               int e[5];
+       });
+} (*fn_complex_t)(union {
+       void *f;
+       char g[16];
+}, struct {
+       int h;
+});
+
+typedef void (* (*signal_t)(int, void (*)(int)))(int);
+
+typedef char * (*fn_ptr_arr1_t[10])(int **);
+
+typedef char * (* const (* const fn_ptr_arr2_t[5])())(char * (*)(int));
+
+struct struct_w_typedefs {
+       int_t a;
+       crazy_ptr_t b;
+       we_need_to_go_deeper_ptr_t c;
+       how_about_this_ptr_t d;
+       ptr_arr_t e;
+       fn_ptr1_t f;
+       printf_fn_t g;
+       fn_ptr2_t h;
+       fn_complex_t i;
+       signal_t j;
+       fn_ptr_arr1_t k;
+       fn_ptr_arr2_t l;
+};
+
+typedef struct {
+       int x;
+       int y;
+       int z;
+} anon_struct_t;
+
+struct struct_fwd;
+
+typedef struct struct_fwd struct_fwd_t;
+
+typedef struct struct_fwd *struct_fwd_ptr_t;
+
+union union_fwd;
+
+typedef union union_fwd union_fwd_t;
+
+typedef union union_fwd *union_fwd_ptr_t;
+
+struct struct_empty {};
+
+struct struct_simple {
+       int a;
+       char b;
+       const int_t *p;
+       struct struct_empty s;
+       enum e2 e;
+       enum {
+               ANON_VAL1 = 1,
+               ANON_VAL2 = 2,
+       } f;
+       int arr1[13];
+       enum e2 arr2[5];
+};
+
+union union_empty {};
+
+union union_simple {
+       void *ptr;
+       int num;
+       int_t num2;
+       union union_empty u;
+};
+
+struct struct_in_struct {
+       struct struct_simple simple;
+       union union_simple also_simple;
+       struct {
+               int a;
+       } not_so_hard_as_well;
+       union {
+               int b;
+               int c;
+       } anon_union_is_good;
+       struct {
+               int d;
+               int e;
+       };
+       union {
+               int f;
+               int g;
+       };
+};
+
+struct struct_with_embedded_stuff {
+       int a;
+       struct {
+               int b;
+               struct {
+                       struct struct_with_embedded_stuff *c;
+                       const char *d;
+               } e;
+               union {
+                       volatile long int f;
+                       void * restrict g;
+               };
+       };
+       union {
+               const int_t *h;
+               void (*i)(char, int, void *);
+       } j;
+       enum {
+               K = 100,
+               L = 200,
+       } m;
+       char n[16];
+       struct {
+               char o;
+               int p;
+               void (*q)(int);
+       } r[5];
+       struct struct_in_struct s[10];
+       int t[11];
+};
+
+struct root_struct {
+       enum e1 _1;
+       enum e2 _2;
+       e2_t _2_1;
+       e3_t _2_2;
+       struct struct_w_typedefs _3;
+       anon_struct_t _7;
+       struct struct_fwd *_8;
+       struct_fwd_t *_9;
+       struct_fwd_ptr_t _10;
+       union union_fwd *_11;
+       union_fwd_t *_12;
+       union_fwd_ptr_t _13;
+       struct struct_with_embedded_stuff _14;
+};
+
+/* ------ END-EXPECTED-OUTPUT ------ */
+
+int f(struct root_struct *s)
+{
+       return 0;
+}
diff --git a/tools/testing/selftests/bpf/test_btf_dump.c b/tools/testing/selftests/bpf/test_btf_dump.c
new file mode 100644 (file)
index 0000000..8f85082
--- /dev/null
@@ -0,0 +1,143 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <linux/err.h>
+#include <btf.h>
+
+#define CHECK(condition, format...) ({                                 \
+       int __ret = !!(condition);                                      \
+       if (__ret) {                                                    \
+               fprintf(stderr, "%s:%d:FAIL ", __func__, __LINE__);     \
+               fprintf(stderr, format);                                \
+       }                                                               \
+       __ret;                                                          \
+})
+
+void btf_dump_printf(void *ctx, const char *fmt, va_list args)
+{
+       vfprintf(ctx, fmt, args);
+}
+
+struct btf_dump_test_case {
+       const char *name;
+       struct btf_dump_opts opts;
+} btf_dump_test_cases[] = {
+       {.name = "btf_dump_test_case_syntax", .opts = {}},
+       {.name = "btf_dump_test_case_ordering", .opts = {}},
+       {.name = "btf_dump_test_case_padding", .opts = {}},
+       {.name = "btf_dump_test_case_packing", .opts = {}},
+       {.name = "btf_dump_test_case_bitfields", .opts = {}},
+       {.name = "btf_dump_test_case_multidim", .opts = {}},
+       {.name = "btf_dump_test_case_namespacing", .opts = {}},
+};
+
+static int btf_dump_all_types(const struct btf *btf,
+                             const struct btf_dump_opts *opts)
+{
+       size_t type_cnt = btf__get_nr_types(btf);
+       struct btf_dump *d;
+       int err = 0, id;
+
+       d = btf_dump__new(btf, NULL, opts, btf_dump_printf);
+       if (IS_ERR(d))
+               return PTR_ERR(d);
+
+       for (id = 1; id <= type_cnt; id++) {
+               err = btf_dump__dump_type(d, id);
+               if (err)
+                       goto done;
+       }
+
+done:
+       btf_dump__free(d);
+       return err;
+}
+
+int test_btf_dump_case(int n, struct btf_dump_test_case *test_case)
+{
+       char test_file[256], out_file[256], diff_cmd[1024];
+       struct btf *btf = NULL;
+       int err = 0, fd = -1;
+       FILE *f = NULL;
+
+       fprintf(stderr, "Test case #%d (%s): ", n, test_case->name);
+
+       snprintf(test_file, sizeof(test_file), "%s.o", test_case->name);
+
+       btf = btf__parse_elf(test_file, NULL);
+       if (CHECK(IS_ERR(btf),
+           "failed to load test BTF: %ld\n", PTR_ERR(btf))) {
+               err = -PTR_ERR(btf);
+               btf = NULL;
+               goto done;
+       }
+
+       snprintf(out_file, sizeof(out_file),
+                "/tmp/%s.output.XXXXXX", test_case->name);
+       fd = mkstemp(out_file);
+       if (CHECK(fd < 0, "failed to create temp output file: %d\n", fd)) {
+               err = fd;
+               goto done;
+       }
+       f = fdopen(fd, "w");
+       if (CHECK(f == NULL, "failed to open temp output file: %s(%d)\n",
+                 strerror(errno), errno)) {
+               close(fd);
+               goto done;
+       }
+
+       test_case->opts.ctx = f;
+       err = btf_dump_all_types(btf, &test_case->opts);
+       fclose(f);
+       close(fd);
+       if (CHECK(err, "failure during C dumping: %d\n", err)) {
+               goto done;
+       }
+
+       snprintf(test_file, sizeof(test_file), "progs/%s.c", test_case->name);
+       /*
+        * Diff test output and expected test output, contained between
+        * START-EXPECTED-OUTPUT and END-EXPECTED-OUTPUT lines in test case.
+        * For expected output lines, everything before '*' is stripped out.
+        * Also lines containing comment start and comment end markers are
+        * ignored. 
+        */
+       snprintf(diff_cmd, sizeof(diff_cmd),
+                "awk '/START-EXPECTED-OUTPUT/{out=1;next} "
+                "/END-EXPECTED-OUTPUT/{out=0} "
+                "/\\/\\*|\\*\\//{next} " /* ignore comment start/end lines */
+                "out {sub(/^[ \\t]*\\*/, \"\"); print}' '%s' | diff -u - '%s'",
+                test_file, out_file);
+       err = system(diff_cmd);
+       if (CHECK(err,
+                 "differing test output, output=%s, err=%d, diff cmd:\n%s\n",
+                 out_file, err, diff_cmd))
+               goto done;
+
+       remove(out_file);
+       fprintf(stderr, "OK\n");
+
+done:
+       btf__free(btf);
+       return err;
+}
+
+int main() {
+       int test_case_cnt, i, err, failed = 0;
+
+       test_case_cnt = sizeof(btf_dump_test_cases) /
+                       sizeof(btf_dump_test_cases[0]);
+
+       for (i = 0; i < test_case_cnt; i++) {
+               err = test_btf_dump_case(i, &btf_dump_test_cases[i]);
+               if (err)
+                       failed++;
+       }
+
+       fprintf(stderr, "%d tests succeeded, %d tests failed.\n",
+               test_case_cnt - failed, failed);
+
+       return failed;
+}