Initial implementation of the debuginfo API
[babeltrace.git] / include / babeltrace / so-info.h
1 #ifndef _BABELTRACE_SO_INFO_H
2 #define _BABELTRACE_SO_INFO_H
3
4 /*
5 * Babeltrace - Executable and Shared Object Debug Info Reader
6 *
7 * Copyright 2015 Antoine Busque <abusque@efficios.com>
8 *
9 * Author: Antoine Busque <abusque@efficios.com>
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining a copy
12 * of this software and associated documentation files (the "Software"), to deal
13 * in the Software without restriction, including without limitation the rights
14 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
15 * copies of the Software, and to permit persons to whom the Software is
16 * furnished to do so, subject to the following conditions:
17 *
18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
26 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
27 * SOFTWARE.
28 */
29
30 #include <stdint.h>
31 #include <stdbool.h>
32 #include <gelf.h>
33 #include <elfutils/libdw.h>
34 #include <babeltrace/babeltrace-internal.h>
35
36 #define DEFAULT_DEBUG_DIR "/usr/lib/debug"
37 #define DEBUG_SUBDIR ".debug/"
38 #define BUILD_ID_SUBDIR ".build-id/"
39 #define BUILD_ID_SUFFIX ".debug"
40
41 struct so_info {
42 /* Base virtual memory address. */
43 uint64_t low_addr;
44 /* Upper bound of exec address space. */
45 uint64_t high_addr;
46 /* Size of exec address space. */
47 uint64_t memsz;
48 /* Paths to ELF and DWARF files. */
49 char *elf_path;
50 char *dwarf_path;
51 /* libelf and libdw objects representing the files. */
52 Elf *elf_file;
53 Dwarf *dwarf_info;
54 /* Optional build ID info. */
55 uint8_t *build_id;
56 size_t build_id_len;
57 /* Optional debug link info. */
58 char *dbg_link_filename;
59 uint32_t dbg_link_crc;
60 /* FDs to ELF and DWARF files. */
61 int elf_fd;
62 int dwarf_fd;
63 /* Denotes whether the executable is position independent code. */
64 bool is_pic:1;
65 /* Denotes whether the SO only has ELF symbols and no DWARF info. */
66 bool is_elf_only:1;
67 };
68
69 struct source_location {
70 uint64_t line_no;
71 char *filename;
72 };
73
74 /**
75 * Initializes the so_info framework. Call this before calling
76 * anything else.
77 *
78 * @returns 0 on success, -1 on failure
79 */
80 BT_HIDDEN
81 int so_info_init(void);
82
83 /**
84 * Instantiate a structure representing an ELF executable, possibly
85 * with DWARF info, located at the given path.
86 *
87 * @param path Path to the ELF file
88 * @param low_addr Base address of the executable
89 * @param memsz In-memory size of the executable
90 * @returns Pointer to the new so_info on success,
91 * NULL on failure.
92 */
93 BT_HIDDEN
94 struct so_info *so_info_create(const char *path, uint64_t low_addr,
95 uint64_t memsz);
96
97 /**
98 * Destroy the given so_info instance
99 *
100 * @param so so_info instance to destroy
101 */
102 BT_HIDDEN
103 void so_info_destroy(struct so_info *so);
104
105 /**
106 * Sets the build ID information for a given so_info instance.
107 *
108 * @param so The so_info instance for which to set
109 * the build ID
110 * @param build_id Array of bytes containing the actual ID
111 * @param build_id_len Length in bytes of the build_id
112 * @returns 0 on success, -1 on failure
113 */
114 BT_HIDDEN
115 int so_info_set_build_id(struct so_info *so, uint8_t *build_id,
116 size_t build_id_len);
117
118 /**
119 * Sets the debug link information for a given so_info instance.
120 *
121 * @param so The so_info instance for which to set
122 * the debug link
123 * @param filename Name of the separate debug info file
124 * @param crc Checksum for the debug info file
125 * @returns 0 on success, -1 on failure
126 */
127 BT_HIDDEN
128 int so_info_set_debug_link(struct so_info *so, char *filename, uint32_t crc);
129
130 /**
131 * Returns whether or not the given SO info \p so contains the address
132 * \p addr.
133 *
134 * @param so so_info instance
135 * @param addr Address to lookup
136 * @returns 1 if \p so contains \p addr, 0 if it does not,
137 * -1 on failure
138 */
139 static inline
140 int so_info_has_address(struct so_info *so, uint64_t addr)
141 {
142 if (!so) {
143 return -1;
144 }
145
146 return addr >= so->low_addr && addr < so->high_addr;
147 }
148
149 /**
150 * Get the name of the function containing a given address within an
151 * executable.
152 *
153 * If no DWARF info is available, the function falls back to ELF
154 * symbols and the "function name" is in fact the name of the closest
155 * symbol, followed by the offset between the symbol and the address.
156 *
157 * On success, if found, the out parameter `func_name` is set. The ownership
158 * of `func_name` is passed to the caller. On failure, `func_name` remains
159 * unchanged.
160 *
161 * @param so so_info instance for the executable containing
162 * the address
163 * @param addr Virtual memory address for which to find the
164 * function name
165 * @param func_name Out parameter, the function name.
166 * @returns 0 on success, -1 on failure
167 */
168 BT_HIDDEN
169 int so_info_lookup_function_name(struct so_info *so, uint64_t addr,
170 char **func_name);
171
172 /**
173 * Get the source location (file name and line number) for a given
174 * address within an executable.
175 *
176 * If no DWARF info is available, the source location cannot be found
177 * and the function will return unsuccesfully.
178 *
179 * On success, if found, the out parameter `src_loc` is set. The ownership
180 * of `src_loc` is passed to the caller. On failure, `src_loc` remains
181 * unchanged.
182 *
183 * @param so so_info instance for the executable containing
184 * the address
185 * @param addr Virtual memory address for which to find the
186 * source location
187 * @param src_loc Out parameter, the source location
188 * @returns 0 on success, -1 on failure
189 */
190 BT_HIDDEN
191 int so_info_lookup_source_location(struct so_info *so, uint64_t addr,
192 struct source_location **src_loc);
193
194 /**
195 * Destroy the given source_location instance
196 *
197 * @param src_loc source_location instance to destroy
198 */
199 BT_HIDDEN
200 void source_location_destroy(struct source_location *src_loc);
201
202 #endif /* _BABELTRACE_SO_INFO_H */
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