<\/p>\n\n\n
As an example I’m using the hexdump executable<\/a> from the REC<\/a> homepage. The program named hexdump reads the files from the command line and outputs the content in hex and ascii. A sample output looks like<\/p>\n\n\n\n The original source code is the following:<\/p>\n\n\n\n As you can see three user functions and some library calls. <\/p>\n\n\n\n Using the current version of holdec the decompiled output looks like:<\/p>\n\n\n\n This is still work in progress since obviously some aspects are still open: <\/p>\n\n\n\n \t\t\t\t\t\t Continue reading 00000000: 7F 45 4C 46 01 01 01 00 00 00 00 00 00 00 00 00.ELF............|
00000010: 02 00 03 00 01 00 00 00 A0 85 04 08 34 00 00 00............4...|
00000020: 40 23 00 00 00 00 00 00 34 00 20 00 05 00 28 00@#......4. ...(.|
00000030: 19 00 16 00 06 00 00 00 34 00 00 00 34 80 04 08........4...4...|
00000040: 34 80 04 08 A0 00 00 00 A0 00 00 00 05 00 00 004...............|
00000050: 04 00 00 00 03 00 00 00 D4 00 00 00 D4 80 04 08................|
...<\/pre>\n\n\n\n#include <stdio.h>\n#include <sys\/stat.h>\n\nvoid dumpline(unsigned char *p, unsigned long offset, int cnt)\n{\n char buff[80];\n int c;\n int len;\n\n sprintf(buff, \"%08lX:\", offset);\n if(cnt > 16)\n cnt = 16;\n for(c = 0; c < cnt; ++c)\n sprintf(buff + c * 3 + 9, \" %02lX\", p[c]);\n while(c++ < 16)\n strcat(buff, \" \");\n len = strlen(buff);\n strcpy(buff + len, \" |\");\n for(c = 0; c < cnt; ++c)\n buff[len + c] = (p[c] >= ' ' && p[c] <= 0x7e) ? p[c] : '.';\n while(c < 16)\n buff[len + c++] = ' ';\n strcpy(buff + len + c, \"|\");\n printf(\"%s\\n\", buff);\n}\n\nint hexdump(char *fname)\n{\n unsigned char buff[16];\n unsigned long offset;\n FILE *fp;\n struct stat st;\n int cnt;\n\n if(!stat(fname, &st)) {\n perror(fname);\n return(1);\n }\n if(!(fp = fopen(fname, \"rb\"))) {\n perror(fname);\n return(1);\n }\n offset = 0;\n while(offset < st.st_size) {\n cnt = fread(buff, 1, sizeof(buff), fp);\n if(!cnt)\n break;\n dumpline(buff, offset, cnt);\n offset += cnt;\n }\n fclose(fp);\n return(0);\n \n}\n\nint main(int argc, char *argv[])\n{\n int i;\n int errs;\n\n errs = 0;\n for(i = 1; i < argc; ++i)\n errs += hexdump(argv[i]);\n return(errs);\n}\n<\/code><\/pre>\n\n\n\n\/\/ address: 08048660.0\n\/\/ full-signature: func(dumpline, return=[], parameter=[<ptr(int(unsigned, 1)),p,unknown>, <int(unsigned, 4),offset,unknown>, <int(undef, 4),cnt,unknown>], varargs=false)\nvoid dumpline(u1* p, u4 offset, d4 cnt)\n{\n (void) sprintf(&buffer, \"%08lX:\", offset);\n if(cnt > 16) {\n (void) STORE(&cnt, 16);\n }\n reg_var1 = 0;\n while(reg_var1 < cnt) {\n (void) sprintf(&buffer + reg_var1 * 3 + 9, \" %02lX\", UNSIGNED_EXTEND(LOAD(p + reg_var1)));\n reg_var1++;\n }\n while(1) {\n reg_var1++;\n if(reg_var1 + -1 > 15) {\n break;\n }\n (void) strcat(&buffer, \" \");\n }\n reg_f = strlen(&buffer);\n (void) strcpy(&buffer + reg_f, \" |\");\n reg_var2 = 0;\n while(reg_var2 < cnt) {\n reg_l = LOAD(p + reg_f + reg_var2) < 32 || LOAD(p + reg_f + reg_var2) > 126 ? 46 : LOAD(p + reg_f + reg_var2);\n (void) STORE(&buffer + reg_f + reg_var2, reg_l);\n reg_var2 += reg_f + 1;\n }\n for(...) {\n \/\/ state = PASSIVE_USED_IN_MULTIPLE_JUMPS\n while(reg_var2 < 16) {\n (void) STORE(&buffer + reg_f + reg_var2, 32);\n reg_var2++;\n }\n }\n (void) strcpy(&buffer + reg_f + reg_var2, \"|\");\n (void) printf(\"%s\\n\", &buffer);\n}\n\n\/\/ address: 080487f0.0\n\/\/ full-signature: func(hexdump, return=[<int(undef, 4),null,unknown>], parameter=[<ptr(int(undef, 1)),fname,unknown>], varargs=false)\nd4 hexdump(d1* fname)\n{\n reg_a = stat(fname, &stat_buffer);\n if(reg_a == 0) {\n (void) perror(fname);\n reg_result = 1;\n } else {\n reg_c = fopen(fname, \"rb\");\n if(reg_c == 0) {\n (void) perror(fname);\n reg_result = 1;\n } else {\n reg_var1 = 0;\n while(reg_var1 < LOAD(&stat_buffer + 20)) {\n reg_g = fread(&read_buffer, 1, 16, reg_c);\n if(reg_g == 0) {\n break;\n }\n (void) dumpline(&read_buffer, reg_var1, reg_g);\n reg_var1 += reg_g;\n }\n (void) fclose(reg_c);\n reg_result = 0;\n }\n }\n return reg_result;\n}\n\n\/\/ address: 080488e0.0\n\/\/ full-signature: func(main, return=[<int(undef, 4),null,unknown>], parameter=[<int(undef, 4),argc,unknown>, <ptr(ptr(int(undef, 1))),argv,unknown>], varargs=false)\nd4 main(d4 argc, d1** argv)\n{\n reg_result = 0;\n reg_var1 = 1;\n while(reg_var1 < argc) {\n reg_e = hexdump(LOAD(argv + reg_var1 * 4));\n reg_result += reg_e;\n reg_var1++;\n }\n return reg_result;\n}\n<\/code><\/pre>\n\n\n\nstruct<\/code> accesses. The function signatures also depend on the type system.<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"