/* $Id: genalias.cpp 96040 2022-08-04 22:00:57Z vboxsync $ */ /** @file * genalias - generate a number of alias objects. * * @note The code has its origin with kLIBC and was added to VBox by the author. */ /* * Copyright (C) 2022 Oracle Corporation * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) as published by the Free Software * Foundation, in version 2 as it comes in the "COPYING" file of the * VirtualBox OSE distribution. VirtualBox OSE is distributed in the * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. */ /********************************************************************************************************************************* * Header Files * *********************************************************************************************************************************/ #include #include #include #include #include #include #define GENALIAS_UNDERSCORED 0 static int Error(const char *pszFormat, ...) { va_list va; fprintf(stderr, "genalias: error: "); va_start(va, pszFormat); vfprintf(stderr, pszFormat, va); va_end(va); return 1; } static int SyntaxError(const char *pszFormat, ...) { va_list va; fprintf(stderr, "genalias: syntax error: "); va_start(va, pszFormat); vfprintf(stderr, pszFormat, va); va_end(va); return 1; } static int WriteAliasObjectAOUT(FILE *pOutput, const char *pszAlias, const char *pszReal) { #pragma pack(1) /* ASSUMES 32-bit target. */ struct AoutHdr { uint32_t a_info; uint32_t a_text; uint32_t a_data; uint32_t a_bss; uint32_t a_syms; uint32_t a_entry; uint32_t a_trsize; uint32_t a_drsize; } Hdr; #define OMAGIC 0407 struct AoutSym { uint32_t n_strx; uint8_t n_type; int8_t n_other; uint16_t n_desc; uint32_t n_value; } Sym; #define N_EXT 1 #define N_INDR 10 #pragma pack() const uint32_t cchAlias = (uint32_t)strlen(pszAlias); const uint32_t cchReal = (uint32_t)strlen(pszReal); uint32_t u32; /* write the header. */ memset(&Hdr, 0, sizeof(Hdr)); Hdr.a_info = OMAGIC; Hdr.a_syms = 2 * sizeof(Sym); if (fwrite(&Hdr, sizeof(Hdr), 1, pOutput) != 1) return -2; /* The alias symbol. */ Sym.n_strx = 4 + cchReal + 1 + GENALIAS_UNDERSCORED; Sym.n_type = N_INDR | N_EXT; Sym.n_other = 0; Sym.n_desc = 0; Sym.n_value = 0; if (fwrite(&Sym, sizeof(Sym), 1, pOutput) != 1) return -2; /* The real symbol. */ Sym.n_strx = 4; Sym.n_type = N_EXT; Sym.n_other = 0; Sym.n_desc = 0; Sym.n_value = 0; if (fwrite(&Sym, sizeof(Sym), 1, pOutput) != 1) return -2; /* the string table. */ u32 = 4 + cchReal + 1 + cchAlias + 1 + GENALIAS_UNDERSCORED * 2; if (fwrite(&u32, 4, 1, pOutput) != 1) return -2; #if GENALIAS_UNDERSCORED if (fputc('_', pOutput) == EOF) return -2; #endif if (fwrite(pszReal, cchReal + 1, 1, pOutput) != 1) return -2; #if GENALIAS_UNDERSCORED if (fputc('_', pOutput) == EOF) return -2; #endif if (fwrite(pszAlias, cchAlias + 1, 1, pOutput) != 1) return -2; return 0; } static int WriteAliasObjectCOFF(FILE *pOutput, const char *pszAlias, const char *pszReal) { #pragma pack(1) struct CoffHdr { uint16_t Machine; uint16_t NumberOfSections; uint32_t TimeDateStamp; uint32_t PointerToSymbolTable; uint32_t NumberOfSymbols; uint16_t SizeOfOptionalHeader; uint16_t Characteristics; } Hdr; struct CoffShdr { char Name[8]; uint32_t VirtualSize; uint32_t VirtualAddress; uint32_t SizeOfRawData; uint32_t PointerToRawData; uint32_t PointerToRelocations; uint32_t PointerToLinenumbers; uint16_t NumberOfRelocations; uint16_t NumberOfLinenumbers; uint32_t Characteristics; } Shdr; #define IMAGE_SCN_LNK_INFO 0x200 #define IMAGE_SCN_LNK_REMOVE 0x800 struct CoffSym { union { char ShortName[8]; struct { uint32_t Zeros; uint32_t Offset; } s; } u; uint32_t Value; uint16_t SectionNumber; uint16_t Type; uint8_t StorageClass; uint8_t NumberOfAuxSymbols; } Sym; #define IMAGE_SYM_UNDEFINED 0 #define IMAGE_SYM_TYPE_NULL 0 #define IMAGE_SYM_CLASS_EXTERNAL 2 #define IMAGE_SYM_CLASS_WEAK_EXTERNAL 105 struct CoffAuxWeakExt { uint32_t TagIndex; uint32_t Characteristics; uint8_t padding[10]; } Aux; #define IMAGE_WEAK_EXTERN_SEARCH_ALIAS 3 assert(sizeof(Hdr) == 20); assert(sizeof(Sym) == 18); assert(sizeof(Aux) == sizeof(Sym)); #pragma pack() const uint32_t cchAlias = (uint32_t)strlen(pszAlias); const uint32_t cchReal = (uint32_t)strlen(pszReal); uint32_t u32; /* write the header. */ Hdr.Machine = 0 /*unknown*/; //0x14c /* i386 */; Hdr.NumberOfSections = 1; Hdr.TimeDateStamp = time(NULL); Hdr.PointerToSymbolTable = sizeof(Hdr) + sizeof(Shdr); Hdr.NumberOfSymbols = 3; Hdr.SizeOfOptionalHeader = 0; Hdr.Characteristics = 0; if (fwrite(&Hdr, sizeof(Hdr), 1, pOutput) != 1) return -2; /* The directive section. */ if (Hdr.NumberOfSections == 1) { memset(&Shdr, 0, sizeof(Shdr)); memcpy(Shdr.Name, ".drectve", 8); Shdr.Characteristics = IMAGE_SCN_LNK_REMOVE | IMAGE_SCN_LNK_INFO; if (fwrite(&Shdr, sizeof(Shdr), 1, pOutput) != 1) return -2; } /* The real symbol. */ memset(&Sym, 0, sizeof(Sym)); Sym.u.s.Offset = 4; Sym.SectionNumber = IMAGE_SYM_UNDEFINED; Sym.Type = IMAGE_SYM_TYPE_NULL; Sym.StorageClass = IMAGE_SYM_CLASS_EXTERNAL; if (fwrite(&Sym, sizeof(Sym), 1, pOutput) != 1) return -2; /* The alias symbol. */ memset(&Sym, 0, sizeof(Sym)); Sym.u.s.Offset = GENALIAS_UNDERSCORED + cchReal + 1 + 4; Sym.SectionNumber = IMAGE_SYM_UNDEFINED; Sym.Type = IMAGE_SYM_TYPE_NULL; Sym.StorageClass = IMAGE_SYM_CLASS_WEAK_EXTERNAL; Sym.NumberOfAuxSymbols = 1; if (fwrite(&Sym, sizeof(Sym), 1, pOutput) != 1) return -2; /* aux entry for that. */ memset(&Aux, 0, sizeof(Aux)); Aux.TagIndex = 0; Aux.Characteristics = IMAGE_WEAK_EXTERN_SEARCH_ALIAS; if (fwrite(&Aux, sizeof(Aux), 1, pOutput) != 1) return -2; /* the string table. */ u32 = 4 + cchReal + 1 + cchAlias + 1 + GENALIAS_UNDERSCORED * 2; if (fwrite(&u32, 4, 1, pOutput) != 1) return -2; #if GENALIAS_UNDERSCORED if (fputc('_', pOutput) == EOF) return -2; #endif if (fwrite(pszReal, cchReal + 1, 1, pOutput) != 1) return -2; #if GENALIAS_UNDERSCORED if (fputc('_', pOutput) == EOF) return -2; #endif if (fwrite(pszAlias, cchAlias + 1, 1, pOutput) != 1) return -2; return 0; } static int WriteAliasObjectELF(FILE *pOutput, const char *pszAlias, const char *pszReal) { RT_NOREF(pOutput, pszAlias, pszReal); fprintf(stderr, "ELF does not support proper aliasing, only option seems to be adding weak symbols with the strong one.\n"); return -1; } static int WriteAliasObjectOMF(FILE *pOutput, const char *pszAlias, const char *pszReal) { const uint32_t cchAlias = (uint32_t)strlen(pszAlias); const uint32_t cchReal = (uint32_t)strlen(pszReal); const uint32_t cchName = cchAlias > 250 ? 250 : cchAlias; uint32_t cch; if (cchReal >= 250) return Error("Symbol '%s' is too long!\n", pszReal); if (cchAlias >= 250) return Error("Symbol '%s' is too long!\n", pszAlias); /* THEADR */ fputc(0x80, pOutput); cch = cchAlias + 2; fputc(cch & 0xff, pOutput); fputc(cch >> 8, pOutput); fputc(cchAlias, pOutput); fwrite(pszAlias, cchAlias, 1, pOutput); fputc(0, pOutput); /* CRC */ /* ALIAS */ fputc(0xc6, pOutput); cch = cchAlias + 1 + cchReal + 1 + GENALIAS_UNDERSCORED * 2 + 1; fputc(cch & 0xff, pOutput); fputc(cch >> 8, pOutput); fputc(cchAlias + GENALIAS_UNDERSCORED, pOutput); if (GENALIAS_UNDERSCORED) fputc('_', pOutput); fwrite(pszAlias, cchAlias, 1, pOutput); fputc(cchReal + GENALIAS_UNDERSCORED, pOutput); if (GENALIAS_UNDERSCORED) fputc('_', pOutput); fwrite(pszReal, cchReal, 1, pOutput); fputc(0, pOutput); /* CRC */ /* MODEND32 */ fputc(0x8b, pOutput); fputc(2, pOutput); fputc(0, pOutput); fputc(0, pOutput); if (fputc(0, pOutput) == EOF) /* CRC */ return -2; return 0; } static int WriteAliasObjectMACHO(FILE *pOutput, const char *pszAlias, const char *pszReal) { RT_NOREF(pOutput, pszAlias, pszReal); fprintf(stderr, "Mach-O support not implemented yet\n"); return -1; } static int CreateAlias(char *pszBuf, size_t cchInput, char *pszFileBuf, char *pszFilename, int (*pfnWriter)(FILE *, const char *, const char *)) { char *pszAlias = pszBuf; char *pszReal; char *pszFile; FILE *pOutput; int rc; RT_NOREF(cchInput); /* * Parse input. */ pszReal = strchr(pszBuf, '='); if (!pszReal) return Error("Malformed request: '%s'\n", pszBuf); *pszReal++ = '\0'; pszFile = strchr(pszReal, '='); if (pszFile) { *pszFile++ = '\0'; strcpy(pszFilename, pszFile); } else strcat(strcpy(pszFilename, pszAlias), ".o"); /* * Open the output file. */ pOutput = fopen(pszFileBuf, "wb"); if (!pOutput) return Error("Failed to open '%s' for writing!\n", pszFileBuf); rc = pfnWriter(pOutput, pszAlias, pszReal); if (rc == -2) rc = Error("Write error writing '%s'!\n", pszFileBuf); fclose(pOutput); return rc; } static int Syntax(void) { printf("syntax: genalias -f -D alias=real[=file] [alias2=real2[=file2] [..]]\n" " OR\n" " genalias -f -D -r \n" "\n" "Format can be: aout, coff or omf\n" "The responsefile is a single argument per line.\n"); return 1; } int main(int argc, char **argv) { static char s_szBuf[4096]; static char s_szFile[1024 + sizeof(s_szBuf)]; int (*pfnWriter)(FILE *pOutput, const char *pszAlias, const char *pszReal); char *pszFilename; int i; int rc; /* * Parse arguments. */ if (argc <= 5) return Syntax(); if (strcmp(argv[1], "-f")) return SyntaxError("Expected -f as the 1st argument.\n"); if (!strcmp(argv[2], "aout")) pfnWriter = WriteAliasObjectAOUT; else if (!strcmp(argv[2], "coff")) pfnWriter = WriteAliasObjectCOFF; else if (!strcmp(argv[2], "elf")) pfnWriter = WriteAliasObjectELF; else if (!strcmp(argv[2], "omf")) pfnWriter = WriteAliasObjectOMF; else if (!strcmp(argv[2], "macho")) pfnWriter = WriteAliasObjectMACHO; else return SyntaxError("Unknown format '%s'.\n", argv[2]); if (strcmp(argv[3], "-D")) return SyntaxError("Expected -D as the 3rd argument\n"); if (!*argv[4]) return SyntaxError("The output directory name is empty.\n"); size_t cchFile = strlen(argv[4]); if (cchFile > sizeof(s_szFile) - sizeof(s_szBuf)) return SyntaxError("The output directory name is too long.\n"); memcpy(s_szFile, argv[4], cchFile); s_szFile[cchFile++] = '/'; pszFilename = &s_szFile[cchFile]; /* anything to do? */ if (argc == 5) return 0; rc = 0; if (!strcmp(argv[5], "-r")) { /* * Responsefile. */ FILE *pResp; if (argc <= 6) return SyntaxError("Missing response file name\n"); pResp = fopen(argv[6], "rt"); if (!pResp) return Error("Failed to open '%s' for reading.\n", argv[6]); i = 0; while (fgets(s_szBuf, sizeof(s_szBuf), pResp)) { size_t cch = strlen(s_szBuf); i++; if (cch == sizeof(s_szBuf) && s_szBuf[cch - 1] != '\n') { rc = Error("Line %d is too long!\n", i); break; } if (cch && s_szBuf[cch - 1] == '\n') s_szBuf[--cch] = '\0'; rc = CreateAlias(s_szBuf, cch, s_szFile, pszFilename, pfnWriter); if (rc) break; } fclose(pResp); } else { /* * Alias descriptors. */ for (i = 5; i < argc; i++) { size_t cch = strlen(argv[i]); if (cch >= sizeof(s_szBuf)) return SyntaxError("Argument %d is too long\n", i); memcpy(s_szBuf, argv[i], cch + 1); rc = CreateAlias(s_szBuf, cch, s_szFile, pszFilename, pfnWriter); if (rc) break; } } return rc; }