src/main/tools/build-runfiles.cc - bazel - Git at Google

 // Copyright 2014 The Bazel Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //    http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
 // This program creates a "runfiles tree" from a "runfiles manifest".
 //
 // The command line arguments are an input manifest INPUT and an output
 // directory RUNFILES. First, the files in the RUNFILES directory are scanned
 // and any extraneous ones are removed. Second, any missing files are created.
 // Finally, a copy of the input manifest is written to RUNFILES/MANIFEST.
 //
 // The input manifest consists of lines, each containing a relative path within
 // the runfiles, a space, and an optional absolute path.  If this second path
 // is present, a symlink is created pointing to it; otherwise an empty file is
 // created.
 //
 // Given the line
 //   <workspace root>/output/path /real/path
 // we will create directories
 //   RUNFILES/<workspace root>
 //   RUNFILES/<workspace root>/output
 // a symlink
 //   RUNFILES/<workspace root>/output/path -> /real/path
 // and the output manifest will contain a line
 //   <workspace root>/output/path /real/path
 //
 // If --use_metadata is supplied, every other line is treated as opaque
 // metadata, and is ignored here.
 //
 // All output paths must be relative and generally (but not always) begin with
 // <workspace root>. No output path may be equal to another.  No output path may
 // be a path prefix of another.

 #define _FILE_OFFSET_BITS 64

 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <unistd.h>

 #include <map>
 #include <string>

 // program_invocation_short_name is not portable.
 static const char *argv0;

 const char *input_filename;
 const char *output_base_dir;

 #define LOG() { \
   fprintf(stderr, "%s (args %s %s): ", \
           argv0, input_filename, output_base_dir); \
 }

 #define DIE(args...) { \
   LOG(); \
   fprintf(stderr, args); \
   fprintf(stderr, "\n"); \
   exit(1); \
 }

 #define PDIE(args...) { \
   int saved_errno = errno; \
   LOG(); \
   fprintf(stderr, args); \
   fprintf(stderr, ": %s [%d]\n", strerror(saved_errno), saved_errno); \
   exit(1); \
 }

 enum FileType {
   FILE_TYPE_REGULAR,
   FILE_TYPE_DIRECTORY,
   FILE_TYPE_SYMLINK
 };

 struct FileInfo {
   FileType type;
   std::string symlink_target;

   bool operator==(const FileInfo &other) const {
     return type == other.type && symlink_target == other.symlink_target;
   }

   bool operator!=(const FileInfo &other) const {
     return !(*this == other);
   }
 };

 typedef std::map<std::string, FileInfo> FileInfoMap;

 class RunfilesCreator {
  public:
   explicit RunfilesCreator(const std::string &output_base)
       : output_base_(output_base),
         output_filename_("MANIFEST"),
         temp_filename_(output_filename_ + ".tmp") {
     SetupOutputBase();
     if (chdir(output_base_.c_str()) != 0) {
       PDIE("chdir '%s'", output_base_.c_str());
     }
   }

   void ReadManifest(const std::string &manifest_file, bool allow_relative,
                     bool use_metadata) {
     // Remove file left over from previous invocation. This ensures that
     // opening succeeds if the existing file is read-only.
     if (unlink(temp_filename_.c_str()) != 0 && errno != ENOENT) {
       PDIE("removing temporary file at '%s/%s'", output_base_.c_str(),
            temp_filename_.c_str());
     }
     FILE *outfile = fopen(temp_filename_.c_str(), "w");
     if (!outfile) {
       PDIE("opening '%s/%s' for writing", output_base_.c_str(),
            temp_filename_.c_str());
     }
     FILE *infile = fopen(manifest_file.c_str(), "r");
     if (!infile) {
       PDIE("opening '%s' for reading", manifest_file.c_str());
     }

     // read input manifest
     int lineno = 0;
     char buf[3 * PATH_MAX];
     while (fgets(buf, sizeof buf, infile)) {
       // copy line to output manifest
       if (fputs(buf, outfile) == EOF) {
         PDIE("writing to '%s/%s'", output_base_.c_str(),
              temp_filename_.c_str());
       }

       // parse line
       ++lineno;
       // Skip metadata lines. They are used solely for
       // dependency checking.
       if (use_metadata && lineno % 2 == 0) continue;

       int n = strlen(buf)-1;
       if (!n || buf[n] != '\n') {
         DIE("missing terminator at line %d: '%s'\n", lineno, buf);
       }
       buf[n] = '\0';
       if (buf[0] ==  '/') {
         DIE("paths must not be absolute: line %d: '%s'\n", lineno, buf);
       }
       const char *s = strchr(buf, ' ');
       if (!s) {
         DIE("missing field delimiter at line %d: '%s'\n", lineno, buf);
       } else if (strchr(s+1, ' ')) {
         DIE("link or target filename contains space on line %d: '%s'\n",
             lineno, buf);
       }
       std::string link(buf, s-buf);
       const char *target = s+1;
       if (!allow_relative && target[0] != '\0' && target[0] != '/'
           && target[1] != ':') {  // Match Windows paths, e.g. C:\foo or C:/foo.
         DIE("expected absolute path at line %d: '%s'\n", lineno, buf);
       }

       FileInfo *info = &manifest_[link];
       if (target[0] == '\0') {
         // No target means an empty file.
         info->type = FILE_TYPE_REGULAR;
       } else {
         info->type = FILE_TYPE_SYMLINK;
         info->symlink_target = target;
       }

       FileInfo parent_info;
       parent_info.type = FILE_TYPE_DIRECTORY;

       while (true) {
         int k = link.rfind('/');
         if (k < 0) break;
         link.erase(k, std::string::npos);
         if (!manifest_.insert(std::make_pair(link, parent_info)).second) break;
       }
     }
     if (fclose(outfile) != 0) {
       PDIE("writing to '%s/%s'", output_base_.c_str(),
            temp_filename_.c_str());
     }
     fclose(infile);

     // Don't delete the temp manifest file.
     manifest_[temp_filename_].type = FILE_TYPE_REGULAR;
   }

   void CreateRunfiles() {
     if (unlink(output_filename_.c_str()) != 0 && errno != ENOENT) {
       PDIE("removing previous file at '%s/%s'", output_base_.c_str(),
            output_filename_.c_str());
     }

     ScanTreeAndPrune(".");
     CreateFiles();

     // rename output file into place
     if (rename(temp_filename_.c_str(), output_filename_.c_str()) != 0) {
       PDIE("renaming '%s/%s' to '%s/%s'",
            output_base_.c_str(), temp_filename_.c_str(),
            output_base_.c_str(), output_filename_.c_str());
     }
   }

  private:
   void SetupOutputBase() {
     struct stat st;
     if (stat(output_base_.c_str(), &st) != 0) {
       // Technically, this will cause problems if the user's umask contains
       // 0200, but we don't care. Anyone who does that deserves what's coming.
       if (mkdir(output_base_.c_str(), 0777) != 0) {
         PDIE("creating directory '%s'", output_base_.c_str());
       }
     } else {
       EnsureDirReadAndWritePerms(output_base_);
     }
   }

   void ScanTreeAndPrune(const std::string &path) {
     // A note on non-empty files:
     // We don't distinguish between empty and non-empty files. That is, if
     // there's a file that has contents, we don't truncate it here, even though
     // the manifest supports creation of empty files, only. Given that
     // .runfiles are *supposed* to be immutable, this shouldn't be a problem.
     EnsureDirReadAndWritePerms(path);

     struct dirent *entry;
     DIR *dh = opendir(path.c_str());
     if (!dh) {
       PDIE("opendir '%s'", path.c_str());
     }

     errno = 0;
     const std::string prefix = (path == "." ? "" : path + "/");
     while ((entry = readdir(dh)) != nullptr) {
       if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, "..")) continue;

       std::string entry_path = prefix + entry->d_name;
       FileInfo actual_info;
       actual_info.type = DentryToFileType(entry_path, entry);

       if (actual_info.type == FILE_TYPE_SYMLINK) {
         ReadLinkOrDie(entry_path, &actual_info.symlink_target);
       }

       FileInfoMap::iterator expected_it = manifest_.find(entry_path);
       if (expected_it == manifest_.end() ||
           expected_it->second != actual_info) {
 #if !defined(__CYGWIN__)
         DelTree(entry_path, actual_info.type);
 #else
         // On Windows, if deleting failed, lamely assume that
         // the link points to the right place.
         if (!DelTree(entry_path, actual_info.type)) {
           manifest_.erase(expected_it);
         }
 #endif
       } else {
         manifest_.erase(expected_it);
         if (actual_info.type == FILE_TYPE_DIRECTORY) {
           ScanTreeAndPrune(entry_path);
         }
       }

       errno = 0;
     }
     if (errno != 0) {
       PDIE("reading directory '%s'", path.c_str());
     }
     closedir(dh);
   }

   void CreateFiles() {
     for (FileInfoMap::const_iterator it = manifest_.begin();
          it != manifest_.end(); ++it) {
       const std::string &path = it->first;
       switch (it->second.type) {
         case FILE_TYPE_DIRECTORY:
           if (mkdir(path.c_str(), 0777) != 0) {
             PDIE("mkdir '%s'", path.c_str());
           }
           break;
         case FILE_TYPE_REGULAR:
           {
             int fd = open(path.c_str(), O_CREAT|O_EXCL|O_WRONLY, 0555);
             if (fd < 0) {
               PDIE("creating empty file '%s'", path.c_str());
             }
             close(fd);
           }
           break;
         case FILE_TYPE_SYMLINK:
           {
             const std::string& target = it->second.symlink_target;
             if (symlink(target.c_str(), path.c_str()) != 0) {
               PDIE("symlinking '%s' -> '%s'", path.c_str(), target.c_str());
             }
           }
           break;
       }
     }
   }

   FileType DentryToFileType(const std::string &path, struct dirent *ent) {
 #ifdef _DIRENT_HAVE_D_TYPE
     if (ent->d_type != DT_UNKNOWN) {
       if (ent->d_type == DT_DIR) {
         return FILE_TYPE_DIRECTORY;
       } else if (ent->d_type == DT_LNK) {
         return FILE_TYPE_SYMLINK;
       } else {
         return FILE_TYPE_REGULAR;
       }
     } else  // NOLINT (the brace is in the next line)
 #endif
     {
       struct stat st;
       LStatOrDie(path, &st);
       if (S_ISDIR(st.st_mode)) {
         return FILE_TYPE_DIRECTORY;
       } else if (S_ISLNK(st.st_mode)) {
         return FILE_TYPE_SYMLINK;
       } else {
         return FILE_TYPE_REGULAR;
       }
     }
   }

   void LStatOrDie(const std::string &path, struct stat *st) {
     if (lstat(path.c_str(), st) != 0) {
       PDIE("lstating file '%s'", path.c_str());
     }
   }

   void StatOrDie(const std::string &path, struct stat *st) {
     if (stat(path.c_str(), st) != 0) {
       PDIE("stating file '%s'", path.c_str());
     }
   }

   void ReadLinkOrDie(const std::string &path, std::string *output) {
     char readlink_buffer[PATH_MAX];
     int sz = readlink(path.c_str(), readlink_buffer, sizeof(readlink_buffer));
     if (sz < 0) {
       PDIE("reading symlink '%s'", path.c_str());
     }
     // readlink returns a non-null terminated string.
     std::string(readlink_buffer, sz).swap(*output);
   }

   void EnsureDirReadAndWritePerms(const std::string &path) {
     const int kMode = 0700;
     struct stat st;
     LStatOrDie(path, &st);
     if ((st.st_mode & kMode) != kMode) {
       int new_mode = st.st_mode | kMode;
       if (chmod(path.c_str(), new_mode) != 0) {
         PDIE("chmod '%s'", path.c_str());
       }
     }
   }

   bool DelTree(const std::string &path, FileType file_type) {
     if (file_type != FILE_TYPE_DIRECTORY) {
       if (unlink(path.c_str()) != 0) {
 #if !defined(__CYGWIN__)
         PDIE("unlinking '%s'", path.c_str());
 #endif
         return false;
       }
       return true;
     }

     EnsureDirReadAndWritePerms(path);

     struct dirent *entry;
     DIR *dh = opendir(path.c_str());
     if (!dh) {
       PDIE("opendir '%s'", path.c_str());
     }
     errno = 0;
     while ((entry = readdir(dh)) != nullptr) {
       if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, "..")) continue;
       const std::string entry_path = path + '/' + entry->d_name;
       FileType entry_file_type = DentryToFileType(entry_path, entry);
       DelTree(entry_path, entry_file_type);
       errno = 0;
     }
     if (errno != 0) {
       PDIE("readdir '%s'", path.c_str());
     }
     closedir(dh);
     if (rmdir(path.c_str()) != 0) {
       PDIE("rmdir '%s'", path.c_str());
     }
     return true;
   }

  private:
   std::string output_base_;
   std::string output_filename_;
   std::string temp_filename_;

   FileInfoMap manifest_;
 };

 int main(int argc, char **argv) {
   argv0 = argv[0];

   argc--; argv++;
   bool allow_relative = false;
   bool use_metadata = false;

   while (argc >= 1) {
     if (strcmp(argv[0], "--allow_relative") == 0) {
       allow_relative = true;
       argc--; argv++;
     } else if (strcmp(argv[0], "--use_metadata") == 0) {
       use_metadata = true;
       argc--; argv++;
     } else {
       break;
     }
   }

   if (argc != 2) {
     fprintf(stderr, "usage: %s "
             "[--allow_relative] [--use_metadata] "
             "INPUT RUNFILES\n",
             argv0);
     return 1;
   }

   input_filename = argv[0];
   output_base_dir = argv[1];

   std::string manifest_file = input_filename;
   if (input_filename[0] != '/') {
     char cwd_buf[PATH_MAX];
     if (getcwd(cwd_buf, sizeof(cwd_buf)) == nullptr) {
       PDIE("getcwd failed");
     }
     manifest_file = std::string(cwd_buf) + '/' + manifest_file;
   }

   RunfilesCreator runfiles_creator(output_base_dir);
   runfiles_creator.ReadManifest(manifest_file, allow_relative, use_metadata);
   runfiles_creator.CreateRunfiles();

   return 0;
 }
	// Copyright 2014 The Bazel Authors. All rights reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	//
	// This program creates a "runfiles tree" from a "runfiles manifest".
	//
	// The command line arguments are an input manifest INPUT and an output
	// directory RUNFILES. First, the files in the RUNFILES directory are scanned
	// and any extraneous ones are removed. Second, any missing files are created.
	// Finally, a copy of the input manifest is written to RUNFILES/MANIFEST.
	//
	// The input manifest consists of lines, each containing a relative path within
	// the runfiles, a space, and an optional absolute path. If this second path
	// is present, a symlink is created pointing to it; otherwise an empty file is
	// created.
	//
	// Given the line
	// <workspace root>/output/path /real/path
	// we will create directories
	// RUNFILES/<workspace root>
	// RUNFILES/<workspace root>/output
	// a symlink
	// RUNFILES/<workspace root>/output/path -> /real/path
	// and the output manifest will contain a line
	// <workspace root>/output/path /real/path
	//
	// If --use_metadata is supplied, every other line is treated as opaque
	// metadata, and is ignored here.
	//
	// All output paths must be relative and generally (but not always) begin with
	// <workspace root>. No output path may be equal to another. No output path may
	// be a path prefix of another.

	#define _FILE_OFFSET_BITS 64

	#include <dirent.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <limits.h>
	#include <stdio.h>
	#include <string.h>
	#include <stdlib.h>
	#include <sys/stat.h>
	#include <unistd.h>

	#include <map>
	#include <string>

	// program_invocation_short_name is not portable.
	static const char *argv0;

	const char *input_filename;
	const char *output_base_dir;

	#define LOG() { \
	fprintf(stderr, "%s (args %s %s): ", \
	argv0, input_filename, output_base_dir); \
	}

	#define DIE(args...) { \
	LOG(); \
	fprintf(stderr, args); \
	fprintf(stderr, "\n"); \
	exit(1); \
	}

	#define PDIE(args...) { \
	int saved_errno = errno; \
	LOG(); \
	fprintf(stderr, args); \
	fprintf(stderr, ": %s [%d]\n", strerror(saved_errno), saved_errno); \
	exit(1); \
	}

	enum FileType {
	FILE_TYPE_REGULAR,
	FILE_TYPE_DIRECTORY,
	FILE_TYPE_SYMLINK
	};

	struct FileInfo {
	FileType type;
	std::string symlink_target;

	bool operator==(const FileInfo &other) const {
	return type == other.type && symlink_target == other.symlink_target;
	}

	bool operator!=(const FileInfo &other) const {
	return !(*this == other);
	}
	};

	typedef std::map<std::string, FileInfo> FileInfoMap;

	class RunfilesCreator {
	public:
	explicit RunfilesCreator(const std::string &output_base)
	: output_base_(output_base),
	output_filename_("MANIFEST"),
	temp_filename_(output_filename_ + ".tmp") {
	SetupOutputBase();
	if (chdir(output_base_.c_str()) != 0) {
	PDIE("chdir '%s'", output_base_.c_str());
	}
	}

	void ReadManifest(const std::string &manifest_file, bool allow_relative,
	bool use_metadata) {
	// Remove file left over from previous invocation. This ensures that
	// opening succeeds if the existing file is read-only.
	if (unlink(temp_filename_.c_str()) != 0 && errno != ENOENT) {
	PDIE("removing temporary file at '%s/%s'", output_base_.c_str(),
	temp_filename_.c_str());
	}
	FILE *outfile = fopen(temp_filename_.c_str(), "w");
	if (!outfile) {
	PDIE("opening '%s/%s' for writing", output_base_.c_str(),
	temp_filename_.c_str());
	}
	FILE *infile = fopen(manifest_file.c_str(), "r");
	if (!infile) {
	PDIE("opening '%s' for reading", manifest_file.c_str());
	}

	// read input manifest
	int lineno = 0;
	char buf[3 * PATH_MAX];
	while (fgets(buf, sizeof buf, infile)) {
	// copy line to output manifest
	if (fputs(buf, outfile) == EOF) {
	PDIE("writing to '%s/%s'", output_base_.c_str(),
	temp_filename_.c_str());
	}

	// parse line
	++lineno;
	// Skip metadata lines. They are used solely for
	// dependency checking.
	if (use_metadata && lineno % 2 == 0) continue;

	int n = strlen(buf)-1;
	if (!n \|\| buf[n] != '\n') {
	DIE("missing terminator at line %d: '%s'\n", lineno, buf);
	}
	buf[n] = '\0';
	if (buf[0] == '/') {
	DIE("paths must not be absolute: line %d: '%s'\n", lineno, buf);
	}
	const char *s = strchr(buf, ' ');
	if (!s) {
	DIE("missing field delimiter at line %d: '%s'\n", lineno, buf);
	} else if (strchr(s+1, ' ')) {
	DIE("link or target filename contains space on line %d: '%s'\n",
	lineno, buf);
	}
	std::string link(buf, s-buf);
	const char *target = s+1;
	if (!allow_relative && target[0] != '\0' && target[0] != '/'
	&& target[1] != ':') { // Match Windows paths, e.g. C:\foo or C:/foo.
	DIE("expected absolute path at line %d: '%s'\n", lineno, buf);
	}

	FileInfo *info = &manifest_[link];
	if (target[0] == '\0') {
	// No target means an empty file.
	info->type = FILE_TYPE_REGULAR;
	} else {
	info->type = FILE_TYPE_SYMLINK;
	info->symlink_target = target;
	}

	FileInfo parent_info;
	parent_info.type = FILE_TYPE_DIRECTORY;

	while (true) {
	int k = link.rfind('/');
	if (k < 0) break;
	link.erase(k, std::string::npos);
	if (!manifest_.insert(std::make_pair(link, parent_info)).second) break;
	}
	}
	if (fclose(outfile) != 0) {
	PDIE("writing to '%s/%s'", output_base_.c_str(),
	temp_filename_.c_str());
	}
	fclose(infile);

	// Don't delete the temp manifest file.
	manifest_[temp_filename_].type = FILE_TYPE_REGULAR;
	}

	void CreateRunfiles() {
	if (unlink(output_filename_.c_str()) != 0 && errno != ENOENT) {
	PDIE("removing previous file at '%s/%s'", output_base_.c_str(),
	output_filename_.c_str());
	}

	ScanTreeAndPrune(".");
	CreateFiles();

	// rename output file into place
	if (rename(temp_filename_.c_str(), output_filename_.c_str()) != 0) {
	PDIE("renaming '%s/%s' to '%s/%s'",
	output_base_.c_str(), temp_filename_.c_str(),
	output_base_.c_str(), output_filename_.c_str());
	}
	}

	private:
	void SetupOutputBase() {
	struct stat st;
	if (stat(output_base_.c_str(), &st) != 0) {
	// Technically, this will cause problems if the user's umask contains
	// 0200, but we don't care. Anyone who does that deserves what's coming.
	if (mkdir(output_base_.c_str(), 0777) != 0) {
	PDIE("creating directory '%s'", output_base_.c_str());
	}
	} else {
	EnsureDirReadAndWritePerms(output_base_);
	}
	}

	void ScanTreeAndPrune(const std::string &path) {
	// A note on non-empty files:
	// We don't distinguish between empty and non-empty files. That is, if
	// there's a file that has contents, we don't truncate it here, even though
	// the manifest supports creation of empty files, only. Given that
	// .runfiles are supposed to be immutable, this shouldn't be a problem.
	EnsureDirReadAndWritePerms(path);

	struct dirent *entry;
	DIR *dh = opendir(path.c_str());
	if (!dh) {
	PDIE("opendir '%s'", path.c_str());
	}

	errno = 0;
	const std::string prefix = (path == "." ? "" : path + "/");
	while ((entry = readdir(dh)) != nullptr) {
	if (!strcmp(entry->d_name, ".") \|\| !strcmp(entry->d_name, "..")) continue;

	std::string entry_path = prefix + entry->d_name;
	FileInfo actual_info;
	actual_info.type = DentryToFileType(entry_path, entry);

	if (actual_info.type == FILE_TYPE_SYMLINK) {
	ReadLinkOrDie(entry_path, &actual_info.symlink_target);
	}

	FileInfoMap::iterator expected_it = manifest_.find(entry_path);
	if (expected_it == manifest_.end() \|\|
	expected_it->second != actual_info) {
	#if !defined(__CYGWIN__)
	DelTree(entry_path, actual_info.type);
	#else
	// On Windows, if deleting failed, lamely assume that
	// the link points to the right place.
	if (!DelTree(entry_path, actual_info.type)) {
	manifest_.erase(expected_it);
	}
	#endif
	} else {
	manifest_.erase(expected_it);
	if (actual_info.type == FILE_TYPE_DIRECTORY) {
	ScanTreeAndPrune(entry_path);
	}
	}

	errno = 0;
	}
	if (errno != 0) {
	PDIE("reading directory '%s'", path.c_str());
	}
	closedir(dh);
	}

	void CreateFiles() {
	for (FileInfoMap::const_iterator it = manifest_.begin();
	it != manifest_.end(); ++it) {
	const std::string &path = it->first;
	switch (it->second.type) {
	case FILE_TYPE_DIRECTORY:
	if (mkdir(path.c_str(), 0777) != 0) {
	PDIE("mkdir '%s'", path.c_str());
	}
	break;
	case FILE_TYPE_REGULAR:
	{
	int fd = open(path.c_str(), O_CREAT\|O_EXCL\|O_WRONLY, 0555);
	if (fd < 0) {
	PDIE("creating empty file '%s'", path.c_str());
	}
	close(fd);
	}
	break;
	case FILE_TYPE_SYMLINK:
	{
	const std::string& target = it->second.symlink_target;
	if (symlink(target.c_str(), path.c_str()) != 0) {
	PDIE("symlinking '%s' -> '%s'", path.c_str(), target.c_str());
	}
	}
	break;
	}
	}
	}

	FileType DentryToFileType(const std::string &path, struct dirent *ent) {
	#ifdef _DIRENT_HAVE_D_TYPE
	if (ent->d_type != DT_UNKNOWN) {
	if (ent->d_type == DT_DIR) {
	return FILE_TYPE_DIRECTORY;
	} else if (ent->d_type == DT_LNK) {
	return FILE_TYPE_SYMLINK;
	} else {
	return FILE_TYPE_REGULAR;
	}
	} else // NOLINT (the brace is in the next line)
	#endif
	{
	struct stat st;
	LStatOrDie(path, &st);
	if (S_ISDIR(st.st_mode)) {
	return FILE_TYPE_DIRECTORY;
	} else if (S_ISLNK(st.st_mode)) {
	return FILE_TYPE_SYMLINK;
	} else {
	return FILE_TYPE_REGULAR;
	}
	}
	}

	void LStatOrDie(const std::string &path, struct stat *st) {
	if (lstat(path.c_str(), st) != 0) {
	PDIE("lstating file '%s'", path.c_str());
	}
	}

	void StatOrDie(const std::string &path, struct stat *st) {
	if (stat(path.c_str(), st) != 0) {
	PDIE("stating file '%s'", path.c_str());
	}
	}

	void ReadLinkOrDie(const std::string &path, std::string *output) {
	char readlink_buffer[PATH_MAX];
	int sz = readlink(path.c_str(), readlink_buffer, sizeof(readlink_buffer));
	if (sz < 0) {
	PDIE("reading symlink '%s'", path.c_str());
	}
	// readlink returns a non-null terminated string.
	std::string(readlink_buffer, sz).swap(*output);
	}

	void EnsureDirReadAndWritePerms(const std::string &path) {
	const int kMode = 0700;
	struct stat st;
	LStatOrDie(path, &st);
	if ((st.st_mode & kMode) != kMode) {
	int new_mode = st.st_mode \| kMode;
	if (chmod(path.c_str(), new_mode) != 0) {
	PDIE("chmod '%s'", path.c_str());
	}
	}
	}

	bool DelTree(const std::string &path, FileType file_type) {
	if (file_type != FILE_TYPE_DIRECTORY) {
	if (unlink(path.c_str()) != 0) {
	#if !defined(__CYGWIN__)
	PDIE("unlinking '%s'", path.c_str());
	#endif
	return false;
	}
	return true;
	}

	EnsureDirReadAndWritePerms(path);

	struct dirent *entry;
	DIR *dh = opendir(path.c_str());
	if (!dh) {
	PDIE("opendir '%s'", path.c_str());
	}
	errno = 0;
	while ((entry = readdir(dh)) != nullptr) {
	if (!strcmp(entry->d_name, ".") \|\| !strcmp(entry->d_name, "..")) continue;
	const std::string entry_path = path + '/' + entry->d_name;
	FileType entry_file_type = DentryToFileType(entry_path, entry);
	DelTree(entry_path, entry_file_type);
	errno = 0;
	}
	if (errno != 0) {
	PDIE("readdir '%s'", path.c_str());
	}
	closedir(dh);
	if (rmdir(path.c_str()) != 0) {
	PDIE("rmdir '%s'", path.c_str());
	}
	return true;
	}

	private:
	std::string output_base_;
	std::string output_filename_;
	std::string temp_filename_;

	FileInfoMap manifest_;
	};

	int main(int argc, char **argv) {
	argv0 = argv[0];

	argc--; argv++;
	bool allow_relative = false;
	bool use_metadata = false;

	while (argc >= 1) {
	if (strcmp(argv[0], "--allow_relative") == 0) {
	allow_relative = true;
	argc--; argv++;
	} else if (strcmp(argv[0], "--use_metadata") == 0) {
	use_metadata = true;
	argc--; argv++;
	} else {
	break;
	}
	}

	if (argc != 2) {
	fprintf(stderr, "usage: %s "
	"[--allow_relative] [--use_metadata] "
	"INPUT RUNFILES\n",
	argv0);
	return 1;
	}

	input_filename = argv[0];
	output_base_dir = argv[1];

	std::string manifest_file = input_filename;
	if (input_filename[0] != '/') {
	char cwd_buf[PATH_MAX];
	if (getcwd(cwd_buf, sizeof(cwd_buf)) == nullptr) {
	PDIE("getcwd failed");
	}
	manifest_file = std::string(cwd_buf) + '/' + manifest_file;
	}

	RunfilesCreator runfiles_creator(output_base_dir);
	runfiles_creator.ReadManifest(manifest_file, allow_relative, use_metadata);
	runfiles_creator.CreateRunfiles();

	return 0;
	}