src/common/elf.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-or-later
   3  *
   4  * Copyright (C) 2015 Antoine Busque <abusque@efficios.com>
   5  */
   6
   7 #ifndef _UST_COMMON_ELF_H
   8 #define _UST_COMMON_ELF_H
   9
  10 #include <stdlib.h>
  11 #include <stdint.h>
  12 #include <stdio.h>
  13 #include <elf.h>
  14
  15 #include <lttng/ust-endian.h>
  16
  17 struct lttng_ust_elf_ehdr {
  18         uint16_t e_type;
  19         uint16_t e_machine;
  20         uint32_t e_version;
  21         uint64_t e_entry;
  22         uint64_t e_phoff;
  23         uint64_t e_shoff;
  24         uint32_t e_flags;
  25         uint16_t e_ehsize;
  26         uint16_t e_phentsize;
  27         uint16_t e_phnum;
  28         uint16_t e_shentsize;
  29         uint16_t e_shnum;
  30         uint16_t e_shstrndx;
  31 };
  32
  33 struct lttng_ust_elf_phdr {
  34         uint32_t p_type;
  35         uint64_t p_offset;
  36         uint64_t p_filesz;
  37         uint64_t p_memsz;
  38         uint64_t p_align;
  39         uint64_t p_vaddr;
  40 };
  41
  42 struct lttng_ust_elf_shdr {
  43         uint32_t sh_name;
  44         uint32_t sh_type;
  45         uint64_t sh_flags;
  46         uint64_t sh_addr;
  47         uint64_t sh_offset;
  48         uint64_t sh_size;
  49         uint32_t sh_link;
  50         uint32_t sh_info;
  51         uint64_t sh_addralign;
  52         uint64_t sh_entsize;
  53 };
  54
  55 struct lttng_ust_elf_nhdr {
  56         uint32_t n_namesz;
  57         uint32_t n_descsz;
  58         uint32_t n_type;
  59 };
  60
  61 struct lttng_ust_elf {
  62         /* Offset in bytes to start of section names string table. */
  63         off_t section_names_offset;
  64         /* Size in bytes of section names string table. */
  65         size_t section_names_size;
  66         char *path;
  67         int fd;
  68         struct lttng_ust_elf_ehdr *ehdr;
  69         uint8_t bitness;
  70         uint8_t endianness;
  71 };
  72
  73 /*
  74  * Determine native endianness in order to convert when reading an ELF
  75  * file if there is a mismatch.
  76  */
  77 #if BYTE_ORDER == LITTLE_ENDIAN
  78 #define NATIVE_ELF_ENDIANNESS ELFDATA2LSB
  79 #else
  80 #define NATIVE_ELF_ENDIANNESS ELFDATA2MSB
  81 #endif
  82
  83 /*
  84  * The size in bytes of the debug link CRC as contained in an ELF
  85  * section.
  86  */
  87 #define ELF_CRC_SIZE            4
  88 /*
  89  * ELF notes are aligned on 4 bytes. ref: ELF specification version
  90  * 1.1 p. 2-5.
  91  */
  92 #define ELF_NOTE_ENTRY_ALIGN    4
  93 /*
  94  * Within an ELF note, the `desc` field is also aligned on 4
  95  * bytes. ref: ELF specification version 1.1 p. 2-5.
  96  */
  97 #define ELF_NOTE_DESC_ALIGN     4
  98
  99 #define bswap(x)                                \
 100         do {                                    \
 101                 switch (sizeof(x)) {            \
 102                 case 8:                         \
 103                         x = bswap_64(x);        \
 104                         break;                  \
 105                 case 4:                         \
 106                         x = bswap_32(x);        \
 107                         break;                  \
 108                 case 2:                         \
 109                         x = bswap_16(x);        \
 110                         break;                  \
 111                 case 1:                         \
 112                         break;                  \
 113                 default:                        \
 114                         abort();                \
 115                 }                               \
 116         } while (0)
 117
 118 #define bswap_phdr(phdr)                \
 119         do {                            \
 120                 bswap((phdr).p_type);   \
 121                 bswap((phdr).p_offset); \
 122                 bswap((phdr).p_filesz); \
 123                 bswap((phdr).p_memsz);  \
 124                 bswap((phdr).p_align);  \
 125                 bswap((phdr).p_vaddr);  \
 126         } while (0)
 127
 128 #define bswap_shdr(shdr)                    \
 129         do {                                \
 130                 bswap((shdr).sh_name);      \
 131                 bswap((shdr).sh_type);      \
 132                 bswap((shdr).sh_flags);     \
 133                 bswap((shdr).sh_addr);      \
 134                 bswap((shdr).sh_offset);    \
 135                 bswap((shdr).sh_size);      \
 136                 bswap((shdr).sh_link);      \
 137                 bswap((shdr).sh_info);      \
 138                 bswap((shdr).sh_addralign); \
 139                 bswap((shdr).sh_entsize);   \
 140         } while (0)
 141
 142 #define bswap_ehdr(ehdr)                                \
 143         do {                                            \
 144                 bswap((ehdr).e_type);                   \
 145                 bswap((ehdr).e_machine);                \
 146                 bswap((ehdr).e_version);                \
 147                 bswap((ehdr).e_entry);                  \
 148                 bswap((ehdr).e_phoff);                  \
 149                 bswap((ehdr).e_shoff);                  \
 150                 bswap((ehdr).e_flags);                  \
 151                 bswap((ehdr).e_ehsize);                 \
 152                 bswap((ehdr).e_phentsize);              \
 153                 bswap((ehdr).e_phnum);                  \
 154                 bswap((ehdr).e_shentsize);              \
 155                 bswap((ehdr).e_shnum);                  \
 156                 bswap((ehdr).e_shstrndx);               \
 157         } while (0)
 158
 159 #define copy_phdr(src_phdr, dst_phdr)                           \
 160         do {                                                    \
 161                 (dst_phdr).p_type = (src_phdr).p_type;          \
 162                 (dst_phdr).p_offset = (src_phdr).p_offset;      \
 163                 (dst_phdr).p_filesz = (src_phdr).p_filesz;      \
 164                 (dst_phdr).p_memsz = (src_phdr).p_memsz;        \
 165                 (dst_phdr).p_align = (src_phdr).p_align;        \
 166                 (dst_phdr).p_vaddr = (src_phdr).p_vaddr;        \
 167         } while (0)
 168
 169 #define copy_shdr(src_shdr, dst_shdr)                                   \
 170         do {                                                            \
 171                 (dst_shdr).sh_name = (src_shdr).sh_name;                \
 172                 (dst_shdr).sh_type = (src_shdr).sh_type;                \
 173                 (dst_shdr).sh_flags = (src_shdr).sh_flags;              \
 174                 (dst_shdr).sh_addr = (src_shdr).sh_addr;                \
 175                 (dst_shdr).sh_offset = (src_shdr).sh_offset;            \
 176                 (dst_shdr).sh_size = (src_shdr).sh_size;                \
 177                 (dst_shdr).sh_link = (src_shdr).sh_link;                \
 178                 (dst_shdr).sh_info = (src_shdr).sh_info;                \
 179                 (dst_shdr).sh_addralign = (src_shdr).sh_addralign;      \
 180                 (dst_shdr).sh_entsize = (src_shdr).sh_entsize;          \
 181         } while (0)
 182
 183 #define copy_ehdr(src_ehdr, dst_ehdr)                                   \
 184         do {                                                            \
 185                 (dst_ehdr).e_type = (src_ehdr).e_type;                  \
 186                 (dst_ehdr).e_machine = (src_ehdr).e_machine;            \
 187                 (dst_ehdr).e_version = (src_ehdr).e_version;            \
 188                 (dst_ehdr).e_entry = (src_ehdr).e_entry;                \
 189                 (dst_ehdr).e_phoff = (src_ehdr).e_phoff;                \
 190                 (dst_ehdr).e_shoff = (src_ehdr).e_shoff;                \
 191                 (dst_ehdr).e_flags = (src_ehdr).e_flags;                \
 192                 (dst_ehdr).e_ehsize = (src_ehdr).e_ehsize;              \
 193                 (dst_ehdr).e_phentsize = (src_ehdr).e_phentsize;        \
 194                 (dst_ehdr).e_phnum = (src_ehdr).e_phnum;                \
 195                 (dst_ehdr).e_shentsize = (src_ehdr).e_shentsize;        \
 196                 (dst_ehdr).e_shnum = (src_ehdr).e_shnum;                \
 197                 (dst_ehdr).e_shstrndx = (src_ehdr).e_shstrndx;          \
 198         } while (0)
 199
 200 static inline
 201 int is_elf_32_bit(struct lttng_ust_elf *elf)
 202 {
 203         return elf->bitness == ELFCLASS32;
 204 }
 205
 206 static inline
 207 int is_elf_native_endian(struct lttng_ust_elf *elf)
 208 {
 209         return elf->endianness == NATIVE_ELF_ENDIANNESS;
 210 }
 211
 212 struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
 213         __attribute__((visibility("hidden")));
 214
 215 void lttng_ust_elf_destroy(struct lttng_ust_elf *elf)
 216         __attribute__((visibility("hidden")));
 217
 218 uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf)
 219         __attribute__((visibility("hidden")));
 220
 221 int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz)
 222         __attribute__((visibility("hidden")));
 223
 224 int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id,
 225                         size_t *length, int *found)
 226         __attribute__((visibility("hidden")));
 227
 228 int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename,
 229                         uint32_t *crc, int *found)
 230         __attribute__((visibility("hidden")));
 231
 232 #endif  /* _UST_COMMON_ELF_H */