tools/extract_data_for_mio.c

   1 #include <string.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdint.h>
   5 #include <stdbool.h>
   6
   7 #define EI_DATA 5
   8 #define EI_NIDENT 16
   9
  10 #define STT_NOTYPE  0
  11 #define STT_OBJECT  1
  12 #define STT_FUNC    2
  13 #define STT_SECTION 3
  14 #define STT_FILE    4
  15 #define STT_COMMON  5
  16 #define STT_TLS     6
  17
  18 #define ELF_ST_TYPE(x) (((unsigned int) x) & 0xf)
  19
  20 typedef uint32_t Elf32_Addr;
  21 typedef uint32_t Elf32_Off;
  22
  23 typedef struct {
  24     unsigned char e_ident[EI_NIDENT];
  25     uint16_t      e_type;
  26     uint16_t      e_machine;
  27     uint32_t      e_version;
  28     Elf32_Addr    e_entry;
  29     Elf32_Off     e_phoff;
  30     Elf32_Off     e_shoff;
  31     uint32_t      e_flags;
  32     uint16_t      e_ehsize;
  33     uint16_t      e_phentsize;
  34     uint16_t      e_phnum;
  35     uint16_t      e_shentsize;
  36     uint16_t      e_shnum;
  37     uint16_t      e_shstrndx;
  38 } Elf32_Ehdr;
  39
  40 typedef struct {
  41     uint32_t   sh_name;
  42     uint32_t   sh_type;
  43     uint32_t   sh_flags;
  44     Elf32_Addr sh_addr;
  45     Elf32_Off  sh_offset;
  46     uint32_t   sh_size;
  47     uint32_t   sh_link;
  48     uint32_t   sh_info;
  49     uint32_t   sh_addralign;
  50     uint32_t   sh_entsize;
  51 } Elf32_Shdr;
  52
  53 typedef struct {
  54     uint32_t      st_name;
  55     Elf32_Addr    st_value;
  56     uint32_t      st_size;
  57     unsigned char st_info;
  58     unsigned char st_other;
  59     uint16_t      st_shndx;
  60 } Elf32_Sym;
  61
  62 typedef struct {
  63     uint16_t magic; //To verify validity of the table
  64     uint16_t vstamp; //Version stamp
  65     uint32_t ilineMax; //Number of line number entries
  66     uint32_t cbLine; //Number of bytes for line number entries
  67     uint32_t cbLineOffset; //Index to start of line numbers
  68     uint32_t idnMax; //Max index into dense numbers
  69     uint32_t cbDnOffset; //Index to start dense numbers
  70     uint32_t ipdMax; //Number of procedures
  71     uint32_t cbPdOffset; //Index to procedure descriptors
  72     uint32_t isymMax; //Number of local symbols
  73     uint32_t cbSymOffset; //Index to start of local symbols
  74     uint32_t ioptMax; //Maximum index into optimization entries
  75     uint32_t cbOptOffset; //Index to start of optimization entries
  76     uint32_t iauxMax; //Number of auxiliary symbols
  77     uint32_t cbAuxOffset; //Index to the start of auxiliary symbols
  78     uint32_t issMax; //Max index into local strings
  79     uint32_t cbSsOffset; //Index to start of local strings
  80     uint32_t issExtMax; //Max index into external strings
  81     uint32_t cbSsExtOffset; //Index to the start of external strings
  82     uint32_t ifdMax; //Number of file descriptors
  83     uint32_t cbFdOffset; //Index to file descriptor
  84     uint32_t crfd; //Number of relative file descriptors
  85     uint32_t cbRfdOffset; //Index to relative file descriptors
  86     uint32_t iextMax; //Maximum index into external symbols
  87     uint32_t cbExtOffset; //Index to the start of external symbols.
  88 } SymbolicHeader;
  89
  90 typedef struct {
  91     uint32_t adr; // Memory address of start of file
  92     uint32_t rss; // Source file name
  93     uint32_t issBase; // Start of local strings
  94     uint32_t cbSs; // Number of bytes in local strings
  95     uint32_t isymBase; // Start of local symbol entries
  96     uint32_t csym; // Count of local symbol entries
  97     uint32_t ilineBase; // Start of line number entries
  98     uint32_t cline; // Count of line number entries
  99     uint32_t ioptBase; // Start of optimization symbol entries
 100     uint32_t copt; // Count of optimization symbol entries
 101     uint16_t ipdFirst; // Start of procedure descriptor table
 102     uint16_t cpd; // Count of procedures descriptors
 103     uint32_t iauxBase; // Start of auxiliary symbol entries
 104     uint32_t caux; // Count of auxiliary symbol entries
 105     uint32_t rfdBase; // Index into relative file descriptors
 106     uint32_t crfd; // Relative file descriptor count
 107     uint32_t flags;
 108     uint32_t cbLineOffset; // Byte offset from header or file ln's
 109     uint32_t cbLine;
 110 } FileDescriptorTable;
 111
 112 typedef struct {
 113     uint32_t iss;
 114     uint32_t value;
 115     uint32_t st_sc_index;
 116 } LocalSymbolsEntry;
 117
 118 typedef enum {
 119     stNil,
 120     stGlobal,
 121     stStatic,
 122     stParam,
 123     stLocal,
 124     stLabel,
 125     stProc,
 126     stBlock,
 127     stEnd,
 128     stMember,
 129     stTypedef,
 130     stFile,
 131     stStaticProc,
 132     stConstant
 133 } StConstants;
 134
 135 uint32_t u32be(uint32_t val) {
 136 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 137     return __builtin_bswap32(val);
 138 #else
 139     return val;
 140 #endif
 141 }
 142
 143 uint16_t u16be(uint16_t val) {
 144 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 145     return __builtin_bswap16(val);
 146 #else
 147     return val;
 148 #endif
 149 }
 150
 151 static bool elf_get_section_range(uint8_t *file, const char *searched_name, uint32_t *address, uint32_t *offset, uint32_t *size, uint32_t *section_index) {
 152     Elf32_Ehdr *ehdr = (Elf32_Ehdr *)file;
 153
 154     for (int i = 0; i < u16be(ehdr->e_shnum); i++) {
 155         if (memcmp("\x7f" "ELF", ehdr->e_ident, 4) != 0) {
 156             fprintf(stderr, "Missing ELF magic\n");
 157             exit(1);
 158         }
 159         if (ehdr->e_ident[EI_DATA] != 2) {
 160             fprintf(stderr, "ELF file is not big-endian\n");
 161             exit(1);
 162         }
 163
 164         Elf32_Shdr *shdr = (Elf32_Shdr *)(file + u32be(ehdr->e_shoff) + i * u16be(ehdr->e_shentsize));
 165         if (u16be(ehdr->e_shstrndx) >= u16be(ehdr->e_shnum)) {
 166             fprintf(stderr, "Invalid ELF file\n");
 167             exit(1);
 168         }
 169         Elf32_Shdr *str_shdr = (Elf32_Shdr *)(file + u32be(ehdr->e_shoff) + u16be(ehdr->e_shstrndx) * u16be(ehdr->e_shentsize));
 170         char *name = (char *)(file + u32be(str_shdr->sh_offset) + u32be(shdr->sh_name));
 171         if (memcmp(name, searched_name, strlen(searched_name)) == 0) {
 172             *address = u32be(shdr->sh_addr);
 173             *offset = u32be(shdr->sh_offset);
 174             *size = u32be(shdr->sh_size);
 175             *section_index = i;
 176             return true;
 177         }
 178     }
 179     return false;
 180 }
 181
 182 int main(int argc, char *argv[]) {
 183     if (argc < 3) {
 184         fprintf(stderr, "Usage: %s INFILE OUTFILE\n", argv[0]);
 185         return 1;
 186     }
 187
 188     FILE *in = fopen(argv[1], "rb");
 189     if (in == NULL) {
 190         perror("fopen couldn't open input file");
 191         exit(1);
 192     }
 193     fseek(in, 0, SEEK_END);
 194     size_t file_size = ftell(in);
 195     fseek(in, 0, SEEK_SET);
 196     uint8_t *file = malloc(file_size);
 197     if (fread(file, 1, file_size, in) != file_size) {
 198         fclose(in);
 199         fprintf(stderr, "Failed to read file: %s\n", argv[1]);
 200         exit(1);
 201     }
 202     fclose(in);
 203
 204     uint32_t data_address, data_offset, data_size, data_index;
 205     if (!elf_get_section_range(file, ".data", &data_address, &data_offset, &data_size, &data_index)) {
 206         fprintf(stderr, "section .data not found\n");
 207         exit(1);
 208     }
 209
 210     uint32_t rodata_address, rodata_offset, rodata_size, rodata_index;
 211     if (elf_get_section_range(file, ".rodata", &rodata_address, &rodata_offset, &rodata_size, &rodata_index)) {
 212         fprintf(stderr, ".rodata section found, please put everything in .data instead (non-const variables)\n");
 213         exit(1);
 214     }
 215
 216     uint32_t symtab_address, symtab_offset, symtab_size, symtab_index;
 217     if (!elf_get_section_range(file, ".symtab", &symtab_address, &symtab_offset, &symtab_size, &symtab_index)) {
 218         fprintf(stderr, "section .symtab not found\n");
 219         exit(1);
 220     }
 221
 222     uint32_t strtab_address, strtab_offset, strtab_size, strtab_index;
 223     if (!elf_get_section_range(file, ".strtab", &strtab_address, &strtab_offset, &strtab_size, &strtab_index)) {
 224         fprintf(stderr, "section .strtab not found\n");
 225         exit(1);
 226     }
 227
 228     // IDO might pad the section to the nearest 16 byte boundary,
 229     // but the mio0 data should not include that. Therefore find
 230     // the "real" end by finding where the last symbol ends.
 231     uint32_t last_symbol_end = 0;
 232
 233     for (uint32_t i = 0; i < symtab_size / sizeof(Elf32_Sym); i++) {
 234         Elf32_Sym *symbol = (Elf32_Sym *)(file + symtab_offset + i * sizeof(Elf32_Sym));
 235 #if DEBUG
 236         const char *name = "(null)";
 237         if (symbol->st_name != 0U) {
 238             name = (const char*)file + strtab_offset + u32be(symbol->st_name);
 239         }
 240         printf("%08x\t%08x\t%02x\t%02x\t%02x\t%s\n", u32be(symbol->st_value), u32be(symbol->st_size), symbol->st_info, symbol->st_other, u16be(symbol->st_shndx), name);
 241 #endif
 242         if (ELF_ST_TYPE(symbol->st_info) == STT_OBJECT && u16be(symbol->st_shndx) == data_index) {
 243             uint32_t symbol_end = u32be(symbol->st_value) + u32be(symbol->st_size);
 244             if (symbol_end > last_symbol_end) {
 245                 last_symbol_end = symbol_end;
 246             }
 247         }
 248     }
 249
 250     uint32_t mdebug_address, mdebug_offset, mdebug_size, mdebug_index;
 251     if (elf_get_section_range(file, ".mdebug", &mdebug_address, &mdebug_offset, &mdebug_size, &mdebug_index)) {
 252         SymbolicHeader *symbolic_header = (SymbolicHeader *)(file + mdebug_offset);
 253
 254         for (uint32_t i = 0; i < u32be(symbolic_header->ifdMax); i++) {
 255             FileDescriptorTable *fdt = (FileDescriptorTable *)(file + u32be(symbolic_header->cbFdOffset) + i * sizeof(FileDescriptorTable));
 256
 257             for (uint32_t j = 0; j < u32be(fdt->csym); j++) {
 258                 LocalSymbolsEntry lse;
 259                 memcpy(&lse, file + u32be(symbolic_header->cbSymOffset) + (u32be(fdt->isymBase) + j) * sizeof(LocalSymbolsEntry), sizeof(LocalSymbolsEntry));
 260
 261                 uint32_t value = u32be(lse.value);
 262                 uint32_t st_sc_index = u32be(lse.st_sc_index);
 263                 uint32_t st = (st_sc_index >> 26);
 264 #ifdef DEBUG
 265                 uint32_t sc = (st_sc_index >> 21) & 0x1f;
 266                 uint32_t index = st_sc_index & 0xfffff;
 267                 uint32_t iss = u32be(lse.iss);
 268                 const char *symbol_name = file + u32be(symbolic_header->cbSsOffset) + iss;
 269                 printf("%s %08x\n", symbol_name, value);
 270 #endif
 271
 272                 if (st == stStatic || st == stGlobal) {
 273                     // Right now just assume length 8 since it's quite much work to extract the real size
 274                     uint32_t symbol_end = value + 8;
 275                     if (symbol_end > last_symbol_end) {
 276                         last_symbol_end = symbol_end;
 277                     }
 278                 }
 279             }
 280         }
 281     }
 282
 283 #ifdef DEBUG
 284     printf("Last symbol end: %08x\n", last_symbol_end);
 285 #endif
 286
 287     size_t new_size = last_symbol_end - data_address;
 288     if (new_size + 16 <= data_size) {
 289         // There seems to be more than 16 bytes padding or non-identified data, so abort and take the original size
 290         new_size = data_size;
 291     } else {
 292         // Make sure we don't cut off non-zero bytes
 293         for (size_t i = new_size; i < data_size; i++) {
 294             if (file[data_offset + i] != 0) {
 295                 // Must be some symbol missing, so abort and take the original size
 296                 new_size = data_size;
 297                 break;
 298             }
 299         }
 300     }
 301
 302     FILE *out = fopen(argv[2], "wb");
 303     fwrite(file + data_offset, 1, new_size, out);
 304     fclose(out);
 305
 306     free(file);
 307     return 0;
 308 }