Ben Gamari pushed to branch wip/T130103 at Glasgow Haskell Compiler / GHC Commits: c77b9301 by Ben Gamari at 2025-06-13T09:58:47-04:00 rts/linker/LoadArchive: Don't rely on file extensions for identification Previously archive members would be identified via their file extension, as described in #13103. We now instead use a more principled approach, relying on the magic number in the member's header. As well, we refactor treatment of archive format detection to improve code clarity and error handling. Closes #13103. - - - - - 1 changed file: - rts/linker/LoadArchive.c Changes: ===================================== rts/linker/LoadArchive.c ===================================== @@ -33,6 +33,7 @@ #define DEBUG_LOG(...) IF_DEBUG(linker, debugBelch("loadArchive: " __VA_ARGS__)) + #if defined(darwin_HOST_OS) || defined(ios_HOST_OS) /* Read 4 bytes and convert to host byte order */ static uint32_t read4Bytes(const char buf[static 4]) @@ -40,7 +41,7 @@ static uint32_t read4Bytes(const char buf[static 4]) return ntohl(*(uint32_t*)buf); } -static bool loadFatArchive(char tmp[static 20], FILE* f, pathchar* path) +static bool loadFatArchive(char input[static 20], FILE* f, pathchar* path) { uint32_t nfat_arch, nfat_offset, cputype, cpusubtype; #if defined(i386_HOST_ARCH) @@ -58,8 +59,9 @@ static bool loadFatArchive(char tmp[static 20], FILE* f, pathchar* path) #error Unknown Darwin architecture #endif - nfat_arch = read4Bytes(tmp + 4); + nfat_arch = read4Bytes(input + 4); DEBUG_LOG("found a fat archive containing %d architectures\n", nfat_arch); + char tmp[20]; nfat_offset = 0; for (uint32_t i = 0; i < nfat_arch; i++) { /* search for the right arch */ @@ -108,7 +110,40 @@ static bool loadFatArchive(char tmp[static 20], FILE* f, pathchar* path) } #endif -static StgBool readThinArchiveMember(int n, int memberSize, pathchar* path, +enum ObjectFileFormat { + NotObject, + PortableExecutable, + ELF, + MachO32, + MachO64, +}; + +static enum ObjectFileFormat identifyObjectFile_(char* buf, size_t sz) +{ + if (sz > 4 && ((uint32_t*)buf)[0] == 0x5a4d) { + return PortableExecutable; + } + if (sz > 4 && memcmp(buf, "\x7f" "ELF", 4) == 0) { + return ELF; + } + if (sz > 4 && ((uint32_t*)buf)[0] == 0xfeedface) { + return MachO32; + } + if (sz > 4 && ((uint32_t*)buf)[0] == 0xfeedfacf) { + return MachO64; + } + return NotObject; +} + +static enum ObjectFileFormat identifyObjectFile(FILE *f) +{ + char buf[32]; + ssize_t sz = fread(buf, 1, 32, f); + CHECK(fseek(f, -sz, SEEK_CUR) == 0); + return identifyObjectFile_(buf, sz); +} + +static bool readThinArchiveMember(int n, int memberSize, pathchar* path, char* fileName, char* image) { bool has_succeeded = false; @@ -149,7 +184,7 @@ inner_fail: return has_succeeded; } -static bool checkFatArchive(char magic[static 20], FILE* f, pathchar* path) +static bool checkFatArchive(char magic[static 4], FILE* f, pathchar* path) { bool success = false; #if defined(darwin_HOST_OS) || defined(ios_HOST_OS) @@ -241,46 +276,21 @@ lookupGNUArchiveIndex(int gnuFileIndexSize, char **fileName_, return true; } -HsInt loadArchive_ (pathchar *path) -{ - char *image = NULL; - HsInt retcode = 0; - int memberSize; - int memberIdx = 0; - FILE *f = NULL; - int n; - size_t thisFileNameSize = (size_t)-1; /* shut up bogus GCC warning */ - char *fileName; - size_t fileNameSize; - bool isGnuIndex, isThin, isImportLib; - char *gnuFileIndex; - int gnuFileIndexSize; - int misalignment = 0; - - DEBUG_LOG("start\n"); - DEBUG_LOG("Loading archive `%" PATH_FMT "'\n", path); +enum ArchiveFormat { + StandardArchive, + ThinArchive, + FatArchive, +}; - /* Check that we haven't already loaded this archive. - Ignore requests to load multiple times */ - if (isAlreadyLoaded(path)) { - IF_DEBUG(linker, - debugBelch("ignoring repeated load of %" PATH_FMT "\n", path)); - return 1; /* success */ +static bool identifyArchiveFormat(FILE *f, pathchar *path, enum ArchiveFormat *out) +{ + char tmp[8]; + size_t n = fread(tmp, 1, 8, f); + if (n != 8) { + errorBelch("loadArchive: Failed reading header from `%" PATH_FMT "'", path); \ + return false; } - gnuFileIndex = NULL; - gnuFileIndexSize = 0; - - fileNameSize = 32; - fileName = stgMallocBytes(fileNameSize, "loadArchive(fileName)"); - - isThin = false; - isImportLib = false; - - f = pathopen(path, WSTR("rb")); - if (!f) - FAIL("loadObj: can't read `%" PATH_FMT "'", path); - /* Check if this is an archive by looking for the magic "!<arch>\n" * string. Usually, if this fails, we belch an error and return. On * Darwin however, we may have a fat archive, which contains archives for @@ -299,12 +309,10 @@ HsInt loadArchive_ (pathchar *path) * its magic "!<arch>\n" string and continue processing just as if * we had a single architecture archive. */ - - n = fread ( tmp, 1, 8, f ); - if (n != 8) { - FAIL("Failed reading header from `%" PATH_FMT "'", path); + if (strncmp(tmp, "!<arch>\n", 8) == 0) { + *out = StandardArchive; + return true; } - if (strncmp(tmp, "!<arch>\n", 8) == 0) {} /* Check if this is a thin archive by looking for the magic string "!<thin>\n" * * ar thin libraries have the exact same format as normal archives except they @@ -321,16 +329,59 @@ HsInt loadArchive_ (pathchar *path) * */ else if (strncmp(tmp, "!<thin>\n", 8) == 0) { - isThin = true; + *out = ThinArchive; + return true; } else { bool success = checkFatArchive(tmp, f, path); - if (!success) - goto fail; + if (!success) { + return false; + } + *out = FatArchive; + return true; } +} + +HsInt loadArchive_ (pathchar *path) +{ + char *image = NULL; + HsInt retcode = 0; + int memberIdx = 0; + FILE *f = NULL; + size_t thisFileNameSize = (size_t) -1; /* shut up bogus GCC warning */ + int misalignment = 0; + + DEBUG_LOG("start\n"); + DEBUG_LOG("Loading archive `%" PATH_FMT "'\n", path); + + /* Check that we haven't already loaded this archive. + Ignore requests to load multiple times */ + if (isAlreadyLoaded(path)) { + IF_DEBUG(linker, + debugBelch("ignoring repeated load of %" PATH_FMT "\n", path)); + return 1; /* success */ + } + + char *gnuFileIndex = NULL; + int gnuFileIndexSize = 0; + + size_t fileNameSize = 32; + char *fileName = stgMallocBytes(fileNameSize, "loadArchive(fileName)"); + + f = pathopen(path, WSTR("rb")); + if (!f) + FAIL("loadObj: can't read `%" PATH_FMT "'", path); + + enum ArchiveFormat archive_fmt; + if (!identifyArchiveFormat(f, path, &archive_fmt)) { + FAIL("failed to identify archive format of %" PATH_FMT ".", path); + } + bool isThin = archive_fmt == ThinArchive; + DEBUG_LOG("loading archive contents\n"); while (1) { + size_t n; DEBUG_LOG("reading at %ld\n", ftell(f)); n = fread ( fileName, 1, 16, f ); if (n != 16) { @@ -350,6 +401,7 @@ HsInt loadArchive_ (pathchar *path) } #endif + char tmp[32]; n = fread ( tmp, 1, 12, f ); if (n != 12) FAIL("Failed reading mod time from `%" PATH_FMT "'", path); @@ -368,9 +420,16 @@ HsInt loadArchive_ (pathchar *path) tmp[10] = '\0'; for (n = 0; isdigit(tmp[n]); n++); tmp[n] = '\0'; - memberSize = atoi(tmp); + size_t memberSize; + { + char *end; + memberSize = strtol(tmp, &end, 10); + if (tmp == end) { + FAIL("Failed to decode member size"); + } + } - DEBUG_LOG("size of this archive member is %d\n", memberSize); + DEBUG_LOG("size of this archive member is %zd\n", memberSize); n = fread ( tmp, 1, 2, f ); if (n != 2) FAIL("Failed reading magic from `%" PATH_FMT "'", path); @@ -378,7 +437,7 @@ HsInt loadArchive_ (pathchar *path) FAIL("Failed reading magic from `%" PATH_FMT "' at %ld. Got %c%c", path, ftell(f), tmp[0], tmp[1]); - isGnuIndex = false; + bool isGnuIndex = false; /* Check for BSD-variant large filenames */ if (0 == strncmp(fileName, "#1/", 3)) { size_t n = 0; @@ -459,12 +518,7 @@ HsInt loadArchive_ (pathchar *path) DEBUG_LOG("Found member file `%s'\n", fileName); - /* TODO: Stop relying on file extensions to determine input formats. - Instead try to match file headers. See #13103. */ - isObject = (thisFileNameSize >= 2 && strncmp(fileName + thisFileNameSize - 2, ".o" , 2) == 0) - || (thisFileNameSize >= 3 && strncmp(fileName + thisFileNameSize - 3, ".lo" , 3) == 0) - || (thisFileNameSize >= 4 && strncmp(fileName + thisFileNameSize - 4, ".p_o", 4) == 0) - || (thisFileNameSize >= 4 && strncmp(fileName + thisFileNameSize - 4, ".obj", 4) == 0); + enum ObjectFileFormat object_fmt = identifyObjectFile(f); #if defined(OBJFORMAT_PEi386) /* @@ -478,13 +532,15 @@ HsInt loadArchive_ (pathchar *path) * * Linker members (e.g. filename / are skipped since they are not needed) */ - isImportLib = thisFileNameSize >= 4 && strncmp(fileName + thisFileNameSize - 4, ".dll", 4) == 0; + bool isImportLib = thisFileNameSize >= 4 && strncmp(fileName + thisFileNameSize - 4, ".dll", 4) == 0; +#else + bool isImportLib = false; #endif // windows DEBUG_LOG("\tthisFileNameSize = %d\n", (int)thisFileNameSize); - DEBUG_LOG("\tisObject = %d\n", isObject); + DEBUG_LOG("\tisObject = %d\n", object_fmt); - if (isObject) { + if (object_fmt != NotObject) { DEBUG_LOG("Member is an object file...loading...\n"); #if defined(darwin_HOST_OS) || defined(ios_HOST_OS) @@ -509,7 +565,7 @@ HsInt loadArchive_ (pathchar *path) } else { - n = fread ( image, 1, memberSize, f ); + size_t n = fread ( image, 1, memberSize, f ); if (n != memberSize) { FAIL("error whilst reading `%" PATH_FMT "'", path); } @@ -527,9 +583,11 @@ HsInt loadArchive_ (pathchar *path) ObjectCode *oc = mkOc(STATIC_OBJECT, path, image, memberSize, false, archiveMemberName, misalignment); #if defined(OBJFORMAT_MACHO) + ASSERT(object_fmt == MachO32 || object_fmt == MachO64); ocInit_MachO( oc ); #endif #if defined(OBJFORMAT_ELF) + ASSERT(object_fmt == ELF); ocInit_ELF( oc ); #endif @@ -574,7 +632,7 @@ while reading filename from `%" PATH_FMT "'", path); "Skipping...\n"); n = fseek(f, memberSize, SEEK_CUR); if (n != 0) - FAIL("error whilst seeking by %d in `%" PATH_FMT "'", + FAIL("error whilst seeking by %zd in `%" PATH_FMT "'", memberSize, path); } #endif @@ -585,7 +643,7 @@ while reading filename from `%" PATH_FMT "'", path); if (!isThin || thisFileNameSize == 0) { n = fseek(f, memberSize, SEEK_CUR); if (n != 0) - FAIL("error whilst seeking by %d in `%" PATH_FMT "'", + FAIL("error whilst seeking by %zd in `%" PATH_FMT "'", memberSize, path); } } View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c77b93013bcef8098a21f5d830aa4f4d... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c77b93013bcef8098a21f5d830aa4f4d... 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