1 /*
2  * Copyright (c) 2016 GitHub, Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #ifndef LIBBCC_ELF_H
17 #define LIBBCC_ELF_H
18 
19 #ifdef __cplusplus
20 extern "C" {
21 #endif
22 
23 #include <stddef.h>
24 #include <stdint.h>
25 
26 struct bcc_elf_usdt {
27   uint64_t pc;
28   uint64_t base_addr;
29   // Virtual address semaphore is found at
30   uint64_t semaphore;
31 
32   const char *provider;
33   const char *name;
34   const char *arg_fmt;
35 
36   // Offset from start of file where the semaphore is at
37   uint64_t semaphore_offset;
38 };
39 
40 // Binary module path, bcc_elf_usdt struct, payload
41 typedef void (*bcc_elf_probecb)(const char *, const struct bcc_elf_usdt *,
42                                 void *);
43 // Symbol name, start address, length, payload
44 // Callback returning a negative value indicates to stop the iteration
45 typedef int (*bcc_elf_symcb)(const char *, uint64_t, uint64_t, void *);
46 // Section idx, str table idx, str length, start address, length, payload
47 typedef int (*bcc_elf_symcb_lazy)(size_t, size_t, size_t, uint64_t, uint64_t,
48              int, void *);
49 // Segment virtual address, memory size, file offset, payload
50 // Callback returning a negative value indicates to stop the iteration
51 typedef int (*bcc_elf_load_sectioncb)(uint64_t, uint64_t, uint64_t, void *);
52 
53 // Iterate over all USDT probes noted in a binary module
54 // Returns -1 on error, and 0 on success
55 int bcc_elf_foreach_usdt(const char *path, bcc_elf_probecb callback,
56                          void *payload);
57 // Iterate over all executable load sections of an ELF
58 // Returns -1 on error, 1 if stopped by callback, and 0 on success
59 int bcc_elf_foreach_load_section(const char *path,
60                                  bcc_elf_load_sectioncb callback,
61                                  void *payload);
62 // Iterate over symbol table of a binary module
63 // Parameter "option" points to a bcc_symbol_option struct to indicate whether
64 // and how to use debuginfo file, and what types of symbols to load.
65 // Returns -1 on error, and 0 on success or stopped by callback
66 int bcc_elf_foreach_sym(const char *path, bcc_elf_symcb callback, void *option,
67                         void *payload);
68 // Similar to bcc_elf_foreach_sym, but pass reference to symbolized string along
69 // with symbolized string length
70 int bcc_elf_foreach_sym_lazy(const char *path, bcc_elf_symcb_lazy callback,
71                              void *option, void *payload);
72 // Iterate over all symbols from current system's vDSO
73 // Returns -1 on error, and 0 on success or stopped by callback
74 int bcc_elf_foreach_vdso_sym(bcc_elf_symcb callback, void *payload);
75 
76 int bcc_elf_get_text_scn_info(const char *path, uint64_t *addr,
77                               uint64_t *offset);
78 
79 int bcc_elf_get_type(const char *path);
80 int bcc_elf_is_shared_obj(const char *path);
81 int bcc_elf_is_exe(const char *path);
82 int bcc_elf_is_vdso(const char *name);
83 int bcc_free_memory();
84 int bcc_elf_get_buildid(const char *path, char *buildid);
85 int bcc_elf_symbol_str(const char *path, size_t section_idx,
86                        size_t str_table_idx, char *out, size_t len,
87                        int debugfile);
88 
89 #ifdef __cplusplus
90 }
91 #endif
92 #endif
93