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author | orivej <orivej@yandex-team.ru> | 2022-02-10 16:44:49 +0300 |
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committer | Daniil Cherednik <dcherednik@yandex-team.ru> | 2022-02-10 16:44:49 +0300 |
commit | 718c552901d703c502ccbefdfc3c9028d608b947 (patch) | |
tree | 46534a98bbefcd7b1f3faa5b52c138ab27db75b7 /contrib/libs/llvm12/lib/Support/TarWriter.cpp | |
parent | e9656aae26e0358d5378e5b63dcac5c8dbe0e4d0 (diff) | |
download | ydb-718c552901d703c502ccbefdfc3c9028d608b947.tar.gz |
Restoring authorship annotation for <orivej@yandex-team.ru>. Commit 1 of 2.
Diffstat (limited to 'contrib/libs/llvm12/lib/Support/TarWriter.cpp')
-rw-r--r-- | contrib/libs/llvm12/lib/Support/TarWriter.cpp | 422 |
1 files changed, 211 insertions, 211 deletions
diff --git a/contrib/libs/llvm12/lib/Support/TarWriter.cpp b/contrib/libs/llvm12/lib/Support/TarWriter.cpp index c7a744f0fc..c0ec2659f8 100644 --- a/contrib/libs/llvm12/lib/Support/TarWriter.cpp +++ b/contrib/libs/llvm12/lib/Support/TarWriter.cpp @@ -1,211 +1,211 @@ -//===-- TarWriter.cpp - Tar archive file creator --------------------------===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// -// -// TarWriter class provides a feature to create a tar archive file. -// -// I put emphasis on simplicity over comprehensiveness when implementing this -// class because we don't need a full-fledged archive file generator in LLVM -// at the moment. -// -// The filename field in the Unix V7 tar header is 100 bytes. Longer filenames -// are stored using the PAX extension. The PAX header is standardized in -// POSIX.1-2001. -// -// The struct definition of UstarHeader is copied from -// https://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5 -// -//===----------------------------------------------------------------------===// - -#include "llvm/Support/TarWriter.h" -#include "llvm/ADT/StringRef.h" -#include "llvm/Support/FileSystem.h" -#include "llvm/Support/MathExtras.h" -#include "llvm/Support/Path.h" - -using namespace llvm; - -// Each file in an archive must be aligned to this block size. -static const int BlockSize = 512; - -struct UstarHeader { - char Name[100]; - char Mode[8]; - char Uid[8]; - char Gid[8]; - char Size[12]; - char Mtime[12]; - char Checksum[8]; - char TypeFlag; - char Linkname[100]; - char Magic[6]; - char Version[2]; - char Uname[32]; - char Gname[32]; - char DevMajor[8]; - char DevMinor[8]; - char Prefix[155]; - char Pad[12]; -}; -static_assert(sizeof(UstarHeader) == BlockSize, "invalid Ustar header"); - -static UstarHeader makeUstarHeader() { - UstarHeader Hdr = {}; - memcpy(Hdr.Magic, "ustar", 5); // Ustar magic - memcpy(Hdr.Version, "00", 2); // Ustar version - return Hdr; -} - -// A PAX attribute is in the form of "<length> <key>=<value>\n" -// where <length> is the length of the entire string including -// the length field itself. An example string is this. -// -// 25 ctime=1084839148.1212\n -// -// This function create such string. -static std::string formatPax(StringRef Key, StringRef Val) { - int Len = Key.size() + Val.size() + 3; // +3 for " ", "=" and "\n" - - // We need to compute total size twice because appending - // a length field could change total size by one. - int Total = Len + Twine(Len).str().size(); - Total = Len + Twine(Total).str().size(); - return (Twine(Total) + " " + Key + "=" + Val + "\n").str(); -} - -// Headers in tar files must be aligned to 512 byte boundaries. -// This function forwards the current file position to the next boundary. -static void pad(raw_fd_ostream &OS) { - uint64_t Pos = OS.tell(); - OS.seek(alignTo(Pos, BlockSize)); -} - -// Computes a checksum for a tar header. -static void computeChecksum(UstarHeader &Hdr) { - // Before computing a checksum, checksum field must be - // filled with space characters. - memset(Hdr.Checksum, ' ', sizeof(Hdr.Checksum)); - - // Compute a checksum and set it to the checksum field. - unsigned Chksum = 0; - for (size_t I = 0; I < sizeof(Hdr); ++I) - Chksum += reinterpret_cast<uint8_t *>(&Hdr)[I]; - snprintf(Hdr.Checksum, sizeof(Hdr.Checksum), "%06o", Chksum); -} - -// Create a tar header and write it to a given output stream. -static void writePaxHeader(raw_fd_ostream &OS, StringRef Path) { - // A PAX header consists of a 512-byte header followed - // by key-value strings. First, create key-value strings. - std::string PaxAttr = formatPax("path", Path); - - // Create a 512-byte header. - UstarHeader Hdr = makeUstarHeader(); - snprintf(Hdr.Size, sizeof(Hdr.Size), "%011zo", PaxAttr.size()); - Hdr.TypeFlag = 'x'; // PAX magic - computeChecksum(Hdr); - - // Write them down. - OS << StringRef(reinterpret_cast<char *>(&Hdr), sizeof(Hdr)); - OS << PaxAttr; - pad(OS); -} - -// Path fits in a Ustar header if -// -// - Path is less than 100 characters long, or -// - Path is in the form of "<prefix>/<name>" where <prefix> is less -// than or equal to 155 characters long and <name> is less than 100 -// characters long. Both <prefix> and <name> can contain extra '/'. -// -// If Path fits in a Ustar header, updates Prefix and Name and returns true. -// Otherwise, returns false. -static bool splitUstar(StringRef Path, StringRef &Prefix, StringRef &Name) { - if (Path.size() < sizeof(UstarHeader::Name)) { - Prefix = ""; - Name = Path; - return true; - } - - // tar 1.13 and earlier unconditionally look at the tar header interpreted - // as an 'oldgnu_header', which has an 'isextended' byte at offset 482 in the - // header, corresponding to offset 137 in the prefix. That's the version of - // tar in gnuwin, so only use 137 of the 155 bytes in the prefix. This means - // we'll need a pax header after 237 bytes of path instead of after 255, - // but in return paths up to 237 bytes work with gnuwin, instead of just - // 137 bytes of directory + 100 bytes of basename previously. - // (tar-1.13 also doesn't support pax headers, but in practice all paths in - // llvm's test suite are short enough for that to not matter.) - const int MaxPrefix = 137; - size_t Sep = Path.rfind('/', MaxPrefix + 1); - if (Sep == StringRef::npos) - return false; - if (Path.size() - Sep - 1 >= sizeof(UstarHeader::Name)) - return false; - - Prefix = Path.substr(0, Sep); - Name = Path.substr(Sep + 1); - return true; -} - -// The PAX header is an extended format, so a PAX header needs -// to be followed by a "real" header. -static void writeUstarHeader(raw_fd_ostream &OS, StringRef Prefix, - StringRef Name, size_t Size) { - UstarHeader Hdr = makeUstarHeader(); - memcpy(Hdr.Name, Name.data(), Name.size()); - memcpy(Hdr.Mode, "0000664", 8); - snprintf(Hdr.Size, sizeof(Hdr.Size), "%011zo", Size); - memcpy(Hdr.Prefix, Prefix.data(), Prefix.size()); - computeChecksum(Hdr); - OS << StringRef(reinterpret_cast<char *>(&Hdr), sizeof(Hdr)); -} - -// Creates a TarWriter instance and returns it. -Expected<std::unique_ptr<TarWriter>> TarWriter::create(StringRef OutputPath, - StringRef BaseDir) { - using namespace sys::fs; - int FD; - if (std::error_code EC = - openFileForWrite(OutputPath, FD, CD_CreateAlways, OF_None)) - return make_error<StringError>("cannot open " + OutputPath, EC); - return std::unique_ptr<TarWriter>(new TarWriter(FD, BaseDir)); -} - -TarWriter::TarWriter(int FD, StringRef BaseDir) - : OS(FD, /*shouldClose=*/true, /*unbuffered=*/false), - BaseDir(std::string(BaseDir)) {} - -// Append a given file to an archive. -void TarWriter::append(StringRef Path, StringRef Data) { - // Write Path and Data. - std::string Fullpath = BaseDir + "/" + sys::path::convert_to_slash(Path); - - // We do not want to include the same file more than once. - if (!Files.insert(Fullpath).second) - return; - - StringRef Prefix; - StringRef Name; - if (splitUstar(Fullpath, Prefix, Name)) { - writeUstarHeader(OS, Prefix, Name, Data.size()); - } else { - writePaxHeader(OS, Fullpath); - writeUstarHeader(OS, "", "", Data.size()); - } - - OS << Data; - pad(OS); - - // POSIX requires tar archives end with two null blocks. - // Here, we write the terminator and then seek back, so that - // the file being output is terminated correctly at any moment. - uint64_t Pos = OS.tell(); - OS << std::string(BlockSize * 2, '\0'); - OS.seek(Pos); - OS.flush(); -} +//===-- TarWriter.cpp - Tar archive file creator --------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// TarWriter class provides a feature to create a tar archive file. +// +// I put emphasis on simplicity over comprehensiveness when implementing this +// class because we don't need a full-fledged archive file generator in LLVM +// at the moment. +// +// The filename field in the Unix V7 tar header is 100 bytes. Longer filenames +// are stored using the PAX extension. The PAX header is standardized in +// POSIX.1-2001. +// +// The struct definition of UstarHeader is copied from +// https://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5 +// +//===----------------------------------------------------------------------===// + +#include "llvm/Support/TarWriter.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/Support/FileSystem.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/Path.h" + +using namespace llvm; + +// Each file in an archive must be aligned to this block size. +static const int BlockSize = 512; + +struct UstarHeader { + char Name[100]; + char Mode[8]; + char Uid[8]; + char Gid[8]; + char Size[12]; + char Mtime[12]; + char Checksum[8]; + char TypeFlag; + char Linkname[100]; + char Magic[6]; + char Version[2]; + char Uname[32]; + char Gname[32]; + char DevMajor[8]; + char DevMinor[8]; + char Prefix[155]; + char Pad[12]; +}; +static_assert(sizeof(UstarHeader) == BlockSize, "invalid Ustar header"); + +static UstarHeader makeUstarHeader() { + UstarHeader Hdr = {}; + memcpy(Hdr.Magic, "ustar", 5); // Ustar magic + memcpy(Hdr.Version, "00", 2); // Ustar version + return Hdr; +} + +// A PAX attribute is in the form of "<length> <key>=<value>\n" +// where <length> is the length of the entire string including +// the length field itself. An example string is this. +// +// 25 ctime=1084839148.1212\n +// +// This function create such string. +static std::string formatPax(StringRef Key, StringRef Val) { + int Len = Key.size() + Val.size() + 3; // +3 for " ", "=" and "\n" + + // We need to compute total size twice because appending + // a length field could change total size by one. + int Total = Len + Twine(Len).str().size(); + Total = Len + Twine(Total).str().size(); + return (Twine(Total) + " " + Key + "=" + Val + "\n").str(); +} + +// Headers in tar files must be aligned to 512 byte boundaries. +// This function forwards the current file position to the next boundary. +static void pad(raw_fd_ostream &OS) { + uint64_t Pos = OS.tell(); + OS.seek(alignTo(Pos, BlockSize)); +} + +// Computes a checksum for a tar header. +static void computeChecksum(UstarHeader &Hdr) { + // Before computing a checksum, checksum field must be + // filled with space characters. + memset(Hdr.Checksum, ' ', sizeof(Hdr.Checksum)); + + // Compute a checksum and set it to the checksum field. + unsigned Chksum = 0; + for (size_t I = 0; I < sizeof(Hdr); ++I) + Chksum += reinterpret_cast<uint8_t *>(&Hdr)[I]; + snprintf(Hdr.Checksum, sizeof(Hdr.Checksum), "%06o", Chksum); +} + +// Create a tar header and write it to a given output stream. +static void writePaxHeader(raw_fd_ostream &OS, StringRef Path) { + // A PAX header consists of a 512-byte header followed + // by key-value strings. First, create key-value strings. + std::string PaxAttr = formatPax("path", Path); + + // Create a 512-byte header. + UstarHeader Hdr = makeUstarHeader(); + snprintf(Hdr.Size, sizeof(Hdr.Size), "%011zo", PaxAttr.size()); + Hdr.TypeFlag = 'x'; // PAX magic + computeChecksum(Hdr); + + // Write them down. + OS << StringRef(reinterpret_cast<char *>(&Hdr), sizeof(Hdr)); + OS << PaxAttr; + pad(OS); +} + +// Path fits in a Ustar header if +// +// - Path is less than 100 characters long, or +// - Path is in the form of "<prefix>/<name>" where <prefix> is less +// than or equal to 155 characters long and <name> is less than 100 +// characters long. Both <prefix> and <name> can contain extra '/'. +// +// If Path fits in a Ustar header, updates Prefix and Name and returns true. +// Otherwise, returns false. +static bool splitUstar(StringRef Path, StringRef &Prefix, StringRef &Name) { + if (Path.size() < sizeof(UstarHeader::Name)) { + Prefix = ""; + Name = Path; + return true; + } + + // tar 1.13 and earlier unconditionally look at the tar header interpreted + // as an 'oldgnu_header', which has an 'isextended' byte at offset 482 in the + // header, corresponding to offset 137 in the prefix. That's the version of + // tar in gnuwin, so only use 137 of the 155 bytes in the prefix. This means + // we'll need a pax header after 237 bytes of path instead of after 255, + // but in return paths up to 237 bytes work with gnuwin, instead of just + // 137 bytes of directory + 100 bytes of basename previously. + // (tar-1.13 also doesn't support pax headers, but in practice all paths in + // llvm's test suite are short enough for that to not matter.) + const int MaxPrefix = 137; + size_t Sep = Path.rfind('/', MaxPrefix + 1); + if (Sep == StringRef::npos) + return false; + if (Path.size() - Sep - 1 >= sizeof(UstarHeader::Name)) + return false; + + Prefix = Path.substr(0, Sep); + Name = Path.substr(Sep + 1); + return true; +} + +// The PAX header is an extended format, so a PAX header needs +// to be followed by a "real" header. +static void writeUstarHeader(raw_fd_ostream &OS, StringRef Prefix, + StringRef Name, size_t Size) { + UstarHeader Hdr = makeUstarHeader(); + memcpy(Hdr.Name, Name.data(), Name.size()); + memcpy(Hdr.Mode, "0000664", 8); + snprintf(Hdr.Size, sizeof(Hdr.Size), "%011zo", Size); + memcpy(Hdr.Prefix, Prefix.data(), Prefix.size()); + computeChecksum(Hdr); + OS << StringRef(reinterpret_cast<char *>(&Hdr), sizeof(Hdr)); +} + +// Creates a TarWriter instance and returns it. +Expected<std::unique_ptr<TarWriter>> TarWriter::create(StringRef OutputPath, + StringRef BaseDir) { + using namespace sys::fs; + int FD; + if (std::error_code EC = + openFileForWrite(OutputPath, FD, CD_CreateAlways, OF_None)) + return make_error<StringError>("cannot open " + OutputPath, EC); + return std::unique_ptr<TarWriter>(new TarWriter(FD, BaseDir)); +} + +TarWriter::TarWriter(int FD, StringRef BaseDir) + : OS(FD, /*shouldClose=*/true, /*unbuffered=*/false), + BaseDir(std::string(BaseDir)) {} + +// Append a given file to an archive. +void TarWriter::append(StringRef Path, StringRef Data) { + // Write Path and Data. + std::string Fullpath = BaseDir + "/" + sys::path::convert_to_slash(Path); + + // We do not want to include the same file more than once. + if (!Files.insert(Fullpath).second) + return; + + StringRef Prefix; + StringRef Name; + if (splitUstar(Fullpath, Prefix, Name)) { + writeUstarHeader(OS, Prefix, Name, Data.size()); + } else { + writePaxHeader(OS, Fullpath); + writeUstarHeader(OS, "", "", Data.size()); + } + + OS << Data; + pad(OS); + + // POSIX requires tar archives end with two null blocks. + // Here, we write the terminator and then seek back, so that + // the file being output is terminated correctly at any moment. + uint64_t Pos = OS.tell(); + OS << std::string(BlockSize * 2, '\0'); + OS.seek(Pos); + OS.flush(); +} |