thodg/libgit2/src/futils.c

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• Hash : 31ecaca2
  Author :
  Date : 2021-09-30T08:11:40
  

  hash: hash functions operate on byte arrays not git_oids Separate the concerns of the hash functions from the git_oid functions. The git_oid structure will need to understand either SHA1 or SHA256; the hash functions should only deal with the appropriate one of these.

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• src/futils.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "futils.h"
  
  #include "runtime.h"
  #include "strmap.h"
  #include "hash.h"
  #include <ctype.h>
  #if GIT_WIN32
  #include "win32/findfile.h"
  #endif
  
  int git_futils_mkpath2file(const char *file_path, const mode_t mode)
  {
  	return git_futils_mkdir(
  		file_path, mode,
  		GIT_MKDIR_PATH | GIT_MKDIR_SKIP_LAST | GIT_MKDIR_VERIFY_DIR);
  }
  
  int git_futils_mktmp(git_buf *path_out, const char *filename, mode_t mode)
  {
  	int fd;
  	mode_t mask;
  
  	p_umask(mask = p_umask(0));
  
  	git_buf_sets(path_out, filename);
  	git_buf_puts(path_out, "_git2_XXXXXX");
  
  	if (git_buf_oom(path_out))
  		return -1;
  
  	if ((fd = p_mkstemp(path_out->ptr)) < 0) {
  		git_error_set(GIT_ERROR_OS,
  			"failed to create temporary file '%s'", path_out->ptr);
  		return -1;
  	}
  
  	if (p_chmod(path_out->ptr, (mode & ~mask))) {
  		git_error_set(GIT_ERROR_OS,
  			"failed to set permissions on file '%s'", path_out->ptr);
  		return -1;
  	}
  
  	return fd;
  }
  
  int git_futils_creat_withpath(const char *path, const mode_t dirmode, const mode_t mode)
  {
  	int fd;
  
  	if (git_futils_mkpath2file(path, dirmode) < 0)
  		return -1;
  
  	fd = p_creat(path, mode);
  	if (fd < 0) {
  		git_error_set(GIT_ERROR_OS, "failed to create file '%s'", path);
  		return -1;
  	}
  
  	return fd;
  }
  
  int git_futils_creat_locked(const char *path, const mode_t mode)
  {
  	int fd = p_open(path, O_WRONLY | O_CREAT | O_EXCL | O_BINARY | O_CLOEXEC,
  		mode);
  
  	if (fd < 0) {
  		int error = errno;
  		git_error_set(GIT_ERROR_OS, "failed to create locked file '%s'", path);
  		switch (error) {
  		case EEXIST:
  			return GIT_ELOCKED;
  		case ENOENT:
  			return GIT_ENOTFOUND;
  		default:
  			return -1;
  		}
  	}
  
  	return fd;
  }
  
  int git_futils_creat_locked_withpath(const char *path, const mode_t dirmode, const mode_t mode)
  {
  	if (git_futils_mkpath2file(path, dirmode) < 0)
  		return -1;
  
  	return git_futils_creat_locked(path, mode);
  }
  
  int git_futils_open_ro(const char *path)
  {
  	int fd = p_open(path, O_RDONLY);
  	if (fd < 0)
  		return git_path_set_error(errno, path, "open");
  	return fd;
  }
  
  int git_futils_truncate(const char *path, int mode)
  {
  	int fd = p_open(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, mode);
  	if (fd < 0)
  		return git_path_set_error(errno, path, "open");
  
  	close(fd);
  	return 0;
  }
  
  int git_futils_filesize(uint64_t *out, git_file fd)
  {
  	struct stat sb;
  
  	if (p_fstat(fd, &sb)) {
  		git_error_set(GIT_ERROR_OS, "failed to stat file descriptor");
  		return -1;
  	}
  
  	if (sb.st_size < 0) {
  		git_error_set(GIT_ERROR_INVALID, "invalid file size");
  		return -1;
  	}
  
  	*out = sb.st_size;
  	return 0;
  }
  
  mode_t git_futils_canonical_mode(mode_t raw_mode)
  {
  	if (S_ISREG(raw_mode))
  		return S_IFREG | GIT_PERMS_CANONICAL(raw_mode);
  	else if (S_ISLNK(raw_mode))
  		return S_IFLNK;
  	else if (S_ISGITLINK(raw_mode))
  		return S_IFGITLINK;
  	else if (S_ISDIR(raw_mode))
  		return S_IFDIR;
  	else
  		return 0;
  }
  
  int git_futils_readbuffer_fd(git_buf *buf, git_file fd, size_t len)
  {
  	ssize_t read_size = 0;
  	size_t alloc_len;
  
  	git_buf_clear(buf);
  
  	if (!git__is_ssizet(len)) {
  		git_error_set(GIT_ERROR_INVALID, "read too large");
  		return -1;
  	}
  
  	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, len, 1);
  	if (git_buf_grow(buf, alloc_len) < 0)
  		return -1;
  
  	/* p_read loops internally to read len bytes */
  	read_size = p_read(fd, buf->ptr, len);
  
  	if (read_size != (ssize_t)len) {
  		git_error_set(GIT_ERROR_OS, "failed to read descriptor");
  		git_buf_dispose(buf);
  		return -1;
  	}
  
  	buf->ptr[read_size] = '\0';
  	buf->size = read_size;
  
  	return 0;
  }
  
  int git_futils_readbuffer_updated(
  	git_buf *out,
  	const char *path,
  	unsigned char checksum[GIT_HASH_SHA1_SIZE],
  	int *updated)
  {
  	int error;
  	git_file fd;
  	struct stat st;
  	git_buf buf = GIT_BUF_INIT;
  	unsigned char checksum_new[GIT_HASH_SHA1_SIZE];
  
  	GIT_ASSERT_ARG(out);
  	GIT_ASSERT_ARG(path && *path);
  
  	if (updated != NULL)
  		*updated = 0;
  
  	if (p_stat(path, &st) < 0)
  		return git_path_set_error(errno, path, "stat");
  
  
  	if (S_ISDIR(st.st_mode)) {
  		git_error_set(GIT_ERROR_INVALID, "requested file is a directory");
  		return GIT_ENOTFOUND;
  	}
  
  	if (!git__is_sizet(st.st_size+1)) {
  		git_error_set(GIT_ERROR_OS, "invalid regular file stat for '%s'", path);
  		return -1;
  	}
  
  	if ((fd = git_futils_open_ro(path)) < 0)
  		return fd;
  
  	if (git_futils_readbuffer_fd(&buf, fd, (size_t)st.st_size) < 0) {
  		p_close(fd);
  		return -1;
  	}
  
  	p_close(fd);
  
  	if (checksum) {
  		if ((error = git_hash_buf(checksum_new, buf.ptr, buf.size, GIT_HASH_ALGORITHM_SHA1)) < 0) {
  			git_buf_dispose(&buf);
  			return error;
  		}
  
  		/*
  		 * If we were given a checksum, we only want to use it if it's different
  		 */
  		if (!memcmp(checksum, checksum_new, GIT_HASH_SHA1_SIZE)) {
  			git_buf_dispose(&buf);
  			if (updated)
  				*updated = 0;
  
  			return 0;
  		}
  
  		memcpy(checksum, checksum_new, GIT_HASH_SHA1_SIZE);
  	}
  
  	/*
  	 * If we're here, the file did change, or the user didn't have an old version
  	 */
  	if (updated != NULL)
  		*updated = 1;
  
  	git_buf_swap(out, &buf);
  	git_buf_dispose(&buf);
  
  	return 0;
  }
  
  int git_futils_readbuffer(git_buf *buf, const char *path)
  {
  	return git_futils_readbuffer_updated(buf, path, NULL, NULL);
  }
  
  int git_futils_writebuffer(
  	const git_buf *buf,	const char *path, int flags, mode_t mode)
  {
  	int fd, do_fsync = 0, error = 0;
  
  	if (!flags)
  		flags = O_CREAT | O_TRUNC | O_WRONLY;
  
  	if ((flags & O_FSYNC) != 0)
  		do_fsync = 1;
  
  	flags &= ~O_FSYNC;
  
  	if (!mode)
  		mode = GIT_FILEMODE_BLOB;
  
  	if ((fd = p_open(path, flags, mode)) < 0) {
  		git_error_set(GIT_ERROR_OS, "could not open '%s' for writing", path);
  		return fd;
  	}
  
  	if ((error = p_write(fd, git_buf_cstr(buf), git_buf_len(buf))) < 0) {
  		git_error_set(GIT_ERROR_OS, "could not write to '%s'", path);
  		(void)p_close(fd);
  		return error;
  	}
  
  	if (do_fsync && (error = p_fsync(fd)) < 0) {
  		git_error_set(GIT_ERROR_OS, "could not fsync '%s'", path);
  		p_close(fd);
  		return error;
  	}
  
  	if ((error = p_close(fd)) < 0) {
  		git_error_set(GIT_ERROR_OS, "error while closing '%s'", path);
  		return error;
  	}
  
  	if (do_fsync && (flags & O_CREAT))
  		error = git_futils_fsync_parent(path);
  
  	return error;
  }
  
  int git_futils_mv_withpath(const char *from, const char *to, const mode_t dirmode)
  {
  	if (git_futils_mkpath2file(to, dirmode) < 0)
  		return -1;
  
  	if (p_rename(from, to) < 0) {
  		git_error_set(GIT_ERROR_OS, "failed to rename '%s' to '%s'", from, to);
  		return -1;
  	}
  
  	return 0;
  }
  
  int git_futils_mmap_ro(git_map *out, git_file fd, off64_t begin, size_t len)
  {
  	return p_mmap(out, len, GIT_PROT_READ, GIT_MAP_SHARED, fd, begin);
  }
  
  int git_futils_mmap_ro_file(git_map *out, const char *path)
  {
  	git_file fd = git_futils_open_ro(path);
  	uint64_t len;
  	int result;
  
  	if (fd < 0)
  		return fd;
  
  	if ((result = git_futils_filesize(&len, fd)) < 0)
  		goto out;
  
  	if (!git__is_sizet(len)) {
  		git_error_set(GIT_ERROR_OS, "file `%s` too large to mmap", path);
  		result = -1;
  		goto out;
  	}
  
  	result = git_futils_mmap_ro(out, fd, 0, (size_t)len);
  out:
  	p_close(fd);
  	return result;
  }
  
  void git_futils_mmap_free(git_map *out)
  {
  	p_munmap(out);
  }
  
  GIT_INLINE(int) mkdir_validate_dir(
  	const char *path,
  	struct stat *st,
  	mode_t mode,
  	uint32_t flags,
  	struct git_futils_mkdir_options *opts)
  {
  	/* with exclusive create, existing dir is an error */
  	if ((flags & GIT_MKDIR_EXCL) != 0) {
  		git_error_set(GIT_ERROR_FILESYSTEM,
  			"failed to make directory '%s': directory exists", path);
  		return GIT_EEXISTS;
  	}
  
  	if ((S_ISREG(st->st_mode) && (flags & GIT_MKDIR_REMOVE_FILES)) ||
  		(S_ISLNK(st->st_mode) && (flags & GIT_MKDIR_REMOVE_SYMLINKS))) {
  		if (p_unlink(path) < 0) {
  			git_error_set(GIT_ERROR_OS, "failed to remove %s '%s'",
  				S_ISLNK(st->st_mode) ? "symlink" : "file", path);
  			return GIT_EEXISTS;
  		}
  
  		opts->perfdata.mkdir_calls++;
  
  		if (p_mkdir(path, mode) < 0) {
  			git_error_set(GIT_ERROR_OS, "failed to make directory '%s'", path);
  			return GIT_EEXISTS;
  		}
  	}
  
  	else if (S_ISLNK(st->st_mode)) {
  		/* Re-stat the target, make sure it's a directory */
  		opts->perfdata.stat_calls++;
  
  		if (p_stat(path, st) < 0) {
  			git_error_set(GIT_ERROR_OS, "failed to make directory '%s'", path);
  			return GIT_EEXISTS;
  		}
  	}
  
  	else if (!S_ISDIR(st->st_mode)) {
  		git_error_set(GIT_ERROR_FILESYSTEM,
  			"failed to make directory '%s': directory exists", path);
  		return GIT_EEXISTS;
  	}
  
  	return 0;
  }
  
  GIT_INLINE(int) mkdir_validate_mode(
  	const char *path,
  	struct stat *st,
  	bool terminal_path,
  	mode_t mode,
  	uint32_t flags,
  	struct git_futils_mkdir_options *opts)
  {
  	if (((terminal_path && (flags & GIT_MKDIR_CHMOD) != 0) ||
  		(flags & GIT_MKDIR_CHMOD_PATH) != 0) && st->st_mode != mode) {
  
  		opts->perfdata.chmod_calls++;
  
  		if (p_chmod(path, mode) < 0) {
  			git_error_set(GIT_ERROR_OS, "failed to set permissions on '%s'", path);
  			return -1;
  		}
  	}
  
  	return 0;
  }
  
  GIT_INLINE(int) mkdir_canonicalize(
  	git_buf *path,
  	uint32_t flags)
  {
  	ssize_t root_len;
  
  	if (path->size == 0) {
  		git_error_set(GIT_ERROR_OS, "attempt to create empty path");
  		return -1;
  	}
  
  	/* Trim trailing slashes (except the root) */
  	if ((root_len = git_path_root(path->ptr)) < 0)
  		root_len = 0;
  	else
  		root_len++;
  
  	while (path->size > (size_t)root_len && path->ptr[path->size - 1] == '/')
  		path->ptr[--path->size] = '\0';
  
  	/* if we are not supposed to made the last element, truncate it */
  	if ((flags & GIT_MKDIR_SKIP_LAST2) != 0) {
  		git_path_dirname_r(path, path->ptr);
  		flags |= GIT_MKDIR_SKIP_LAST;
  	}
  	if ((flags & GIT_MKDIR_SKIP_LAST) != 0) {
  		git_path_dirname_r(path, path->ptr);
  	}
  
  	/* We were either given the root path (or trimmed it to
  	* the root), we don't have anything to do.
  	*/
  	if (path->size <= (size_t)root_len)
  		git_buf_clear(path);
  
  	return 0;
  }
  
  int git_futils_mkdir(
  	const char *path,
  	mode_t mode,
  	uint32_t flags)
  {
  	git_buf make_path = GIT_BUF_INIT, parent_path = GIT_BUF_INIT;
  	const char *relative;
  	struct git_futils_mkdir_options opts = { 0 };
  	struct stat st;
  	size_t depth = 0;
  	int len = 0, root_len, error;
  
  	if ((error = git_buf_puts(&make_path, path)) < 0 ||
  		(error = mkdir_canonicalize(&make_path, flags)) < 0 ||
  		(error = git_buf_puts(&parent_path, make_path.ptr)) < 0 ||
  		make_path.size == 0)
  		goto done;
  
  	root_len = git_path_root(make_path.ptr);
  
  	/* find the first parent directory that exists.  this will be used
  	 * as the base to dirname_relative.
  	 */
  	for (relative = make_path.ptr; parent_path.size; ) {
  		error = p_lstat(parent_path.ptr, &st);
  
  		if (error == 0) {
  			break;
  		} else if (errno != ENOENT) {
  			git_error_set(GIT_ERROR_OS, "failed to stat '%s'", parent_path.ptr);
  			error = -1;
  			goto done;
  		}
  
  		depth++;
  
  		/* examine the parent of the current path */
  		if ((len = git_path_dirname_r(&parent_path, parent_path.ptr)) < 0) {
  			error = len;
  			goto done;
  		}
  
  		GIT_ASSERT(len);
  
  		/*
  		 * We've walked all the given path's parents and it's either relative
  		 * (the parent is simply '.') or rooted (the length is less than or
  		 * equal to length of the root path).  The path may be less than the
  		 * root path length on Windows, where `C:` == `C:/`.
  		 */
  		if ((len == 1 && parent_path.ptr[0] == '.') ||
  		    (len == 1 && parent_path.ptr[0] == '/') ||
  		    len <= root_len) {
  			relative = make_path.ptr;
  			break;
  		}
  
  		relative = make_path.ptr + len + 1;
  
  		/* not recursive? just make this directory relative to its parent. */
  		if ((flags & GIT_MKDIR_PATH) == 0)
  			break;
  	}
  
  	/* we found an item at the location we're trying to create,
  	 * validate it.
  	 */
  	if (depth == 0) {
  		error = mkdir_validate_dir(make_path.ptr, &st, mode, flags, &opts);
  
  		if (!error)
  			error = mkdir_validate_mode(
  				make_path.ptr, &st, true, mode, flags, &opts);
  
  		goto done;
  	}
  
  	/* we already took `SKIP_LAST` and `SKIP_LAST2` into account when
  	 * canonicalizing `make_path`.
  	 */
  	flags &= ~(GIT_MKDIR_SKIP_LAST2 | GIT_MKDIR_SKIP_LAST);
  
  	error = git_futils_mkdir_relative(relative,
  		parent_path.size ? parent_path.ptr : NULL, mode, flags, &opts);
  
  done:
  	git_buf_dispose(&make_path);
  	git_buf_dispose(&parent_path);
  	return error;
  }
  
  int git_futils_mkdir_r(const char *path, const mode_t mode)
  {
  	return git_futils_mkdir(path, mode, GIT_MKDIR_PATH);
  }
  
  int git_futils_mkdir_relative(
  	const char *relative_path,
  	const char *base,
  	mode_t mode,
  	uint32_t flags,
  	struct git_futils_mkdir_options *opts)
  {
  	git_buf make_path = GIT_BUF_INIT;
  	ssize_t root = 0, min_root_len;
  	char lastch = '/', *tail;
  	struct stat st;
  	struct git_futils_mkdir_options empty_opts = {0};
  	int error;
  
  	if (!opts)
  		opts = &empty_opts;
  
  	/* build path and find "root" where we should start calling mkdir */
  	if (git_path_join_unrooted(&make_path, relative_path, base, &root) < 0)
  		return -1;
  
  	if ((error = mkdir_canonicalize(&make_path, flags)) < 0 ||
  		make_path.size == 0)
  		goto done;
  
  	/* if we are not supposed to make the whole path, reset root */
  	if ((flags & GIT_MKDIR_PATH) == 0)
  		root = git_buf_rfind(&make_path, '/');
  
  	/* advance root past drive name or network mount prefix */
  	min_root_len = git_path_root(make_path.ptr);
  	if (root < min_root_len)
  		root = min_root_len;
  	while (root >= 0 && make_path.ptr[root] == '/')
  		++root;
  
  	/* clip root to make_path length */
  	if (root > (ssize_t)make_path.size)
  		root = (ssize_t)make_path.size; /* i.e. NUL byte of string */
  	if (root < 0)
  		root = 0;
  
  	/* walk down tail of path making each directory */
  	for (tail = &make_path.ptr[root]; *tail; *tail = lastch) {
  		bool mkdir_attempted = false;
  
  		/* advance tail to include next path component */
  		while (*tail == '/')
  			tail++;
  		while (*tail && *tail != '/')
  			tail++;
  
  		/* truncate path at next component */
  		lastch = *tail;
  		*tail = '\0';
  		st.st_mode = 0;
  
  		if (opts->dir_map && git_strmap_exists(opts->dir_map, make_path.ptr))
  			continue;
  
  		/* See what's going on with this path component */
  		opts->perfdata.stat_calls++;
  
  retry_lstat:
  		if (p_lstat(make_path.ptr, &st) < 0) {
  			if (mkdir_attempted || errno != ENOENT) {
  				git_error_set(GIT_ERROR_OS, "cannot access component in path '%s'", make_path.ptr);
  				error = -1;
  				goto done;
  			}
  
  			git_error_clear();
  			opts->perfdata.mkdir_calls++;
  			mkdir_attempted = true;
  			if (p_mkdir(make_path.ptr, mode) < 0) {
  				if (errno == EEXIST)
  					goto retry_lstat;
  				git_error_set(GIT_ERROR_OS, "failed to make directory '%s'", make_path.ptr);
  				error = -1;
  				goto done;
  			}
  		} else {
  			if ((error = mkdir_validate_dir(
  				make_path.ptr, &st, mode, flags, opts)) < 0)
  				goto done;
  		}
  
  		/* chmod if requested and necessary */
  		if ((error = mkdir_validate_mode(
  			make_path.ptr, &st, (lastch == '\0'), mode, flags, opts)) < 0)
  			goto done;
  
  		if (opts->dir_map && opts->pool) {
  			char *cache_path;
  			size_t alloc_size;
  
  			GIT_ERROR_CHECK_ALLOC_ADD(&alloc_size, make_path.size, 1);
  			cache_path = git_pool_malloc(opts->pool, alloc_size);
  			GIT_ERROR_CHECK_ALLOC(cache_path);
  
  			memcpy(cache_path, make_path.ptr, make_path.size + 1);
  
  			if ((error = git_strmap_set(opts->dir_map, cache_path, cache_path)) < 0)
  				goto done;
  		}
  	}
  
  	error = 0;
  
  	/* check that full path really is a directory if requested & needed */
  	if ((flags & GIT_MKDIR_VERIFY_DIR) != 0 &&
  		lastch != '\0') {
  		opts->perfdata.stat_calls++;
  
  		if (p_stat(make_path.ptr, &st) < 0 || !S_ISDIR(st.st_mode)) {
  			git_error_set(GIT_ERROR_OS, "path is not a directory '%s'",
  				make_path.ptr);
  			error = GIT_ENOTFOUND;
  		}
  	}
  
  done:
  	git_buf_dispose(&make_path);
  	return error;
  }
  
  typedef struct {
  	const char *base;
  	size_t baselen;
  	uint32_t flags;
  	int depth;
  } futils__rmdir_data;
  
  #define FUTILS_MAX_DEPTH 100
  
  static int futils__error_cannot_rmdir(const char *path, const char *filemsg)
  {
  	if (filemsg)
  		git_error_set(GIT_ERROR_OS, "could not remove directory '%s': %s",
  				   path, filemsg);
  	else
  		git_error_set(GIT_ERROR_OS, "could not remove directory '%s'", path);
  
  	return -1;
  }
  
  static int futils__rm_first_parent(git_buf *path, const char *ceiling)
  {
  	int error = GIT_ENOTFOUND;
  	struct stat st;
  
  	while (error == GIT_ENOTFOUND) {
  		git_buf_rtruncate_at_char(path, '/');
  
  		if (!path->size || git__prefixcmp(path->ptr, ceiling) != 0)
  			error = 0;
  		else if (p_lstat_posixly(path->ptr, &st) == 0) {
  			if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode))
  				error = p_unlink(path->ptr);
  			else if (!S_ISDIR(st.st_mode))
  				error = -1; /* fail to remove non-regular file */
  		} else if (errno != ENOTDIR)
  			error = -1;
  	}
  
  	if (error)
  		futils__error_cannot_rmdir(path->ptr, "cannot remove parent");
  
  	return error;
  }
  
  static int futils__rmdir_recurs_foreach(void *opaque, git_buf *path)
  {
  	int error = 0;
  	futils__rmdir_data *data = opaque;
  	struct stat st;
  
  	if (data->depth > FUTILS_MAX_DEPTH)
  		error = futils__error_cannot_rmdir(
  			path->ptr, "directory nesting too deep");
  
  	else if ((error = p_lstat_posixly(path->ptr, &st)) < 0) {
  		if (errno == ENOENT)
  			error = 0;
  		else if (errno == ENOTDIR) {
  			/* asked to remove a/b/c/d/e and a/b is a normal file */
  			if ((data->flags & GIT_RMDIR_REMOVE_BLOCKERS) != 0)
  				error = futils__rm_first_parent(path, data->base);
  			else
  				futils__error_cannot_rmdir(
  					path->ptr, "parent is not directory");
  		}
  		else
  			error = git_path_set_error(errno, path->ptr, "rmdir");
  	}
  
  	else if (S_ISDIR(st.st_mode)) {
  		data->depth++;
  
  		error = git_path_direach(path, 0, futils__rmdir_recurs_foreach, data);
  
  		data->depth--;
  
  		if (error < 0)
  			return error;
  
  		if (data->depth == 0 && (data->flags & GIT_RMDIR_SKIP_ROOT) != 0)
  			return error;
  
  		if ((error = p_rmdir(path->ptr)) < 0) {
  			if ((data->flags & GIT_RMDIR_SKIP_NONEMPTY) != 0 &&
  				(errno == ENOTEMPTY || errno == EEXIST || errno == EBUSY))
  				error = 0;
  			else
  				error = git_path_set_error(errno, path->ptr, "rmdir");
  		}
  	}
  
  	else if ((data->flags & GIT_RMDIR_REMOVE_FILES) != 0) {
  		if (p_unlink(path->ptr) < 0)
  			error = git_path_set_error(errno, path->ptr, "remove");
  	}
  
  	else if ((data->flags & GIT_RMDIR_SKIP_NONEMPTY) == 0)
  		error = futils__error_cannot_rmdir(path->ptr, "still present");
  
  	return error;
  }
  
  static int futils__rmdir_empty_parent(void *opaque, const char *path)
  {
  	futils__rmdir_data *data = opaque;
  	int error = 0;
  
  	if (strlen(path) <= data->baselen)
  		error = GIT_ITEROVER;
  
  	else if (p_rmdir(path) < 0) {
  		int en = errno;
  
  		if (en == ENOENT || en == ENOTDIR) {
  			/* do nothing */
  		} else if ((data->flags & GIT_RMDIR_SKIP_NONEMPTY) == 0 &&
  			en == EBUSY) {
  			error = git_path_set_error(errno, path, "rmdir");
  		} else if (en == ENOTEMPTY || en == EEXIST || en == EBUSY) {
  			error = GIT_ITEROVER;
  		} else {
  			error = git_path_set_error(errno, path, "rmdir");
  		}
  	}
  
  	return error;
  }
  
  int git_futils_rmdir_r(
  	const char *path, const char *base, uint32_t flags)
  {
  	int error;
  	git_buf fullpath = GIT_BUF_INIT;
  	futils__rmdir_data data;
  
  	/* build path and find "root" where we should start calling mkdir */
  	if (git_path_join_unrooted(&fullpath, path, base, NULL) < 0)
  		return -1;
  
  	memset(&data, 0, sizeof(data));
  	data.base    = base ? base : "";
  	data.baselen = base ? strlen(base) : 0;
  	data.flags   = flags;
  
  	error = futils__rmdir_recurs_foreach(&data, &fullpath);
  
  	/* remove now-empty parents if requested */
  	if (!error && (flags & GIT_RMDIR_EMPTY_PARENTS) != 0)
  		error = git_path_walk_up(
  			&fullpath, base, futils__rmdir_empty_parent, &data);
  
  	if (error == GIT_ITEROVER) {
  		git_error_clear();
  		error = 0;
  	}
  
  	git_buf_dispose(&fullpath);
  
  	return error;
  }
  
  int git_futils_fake_symlink(const char *target, const char *path)
  {
  	int retcode = GIT_ERROR;
  	int fd = git_futils_creat_withpath(path, 0755, 0644);
  	if (fd >= 0) {
  		retcode = p_write(fd, target, strlen(target));
  		p_close(fd);
  	}
  	return retcode;
  }
  
  static int cp_by_fd(int ifd, int ofd, bool close_fd_when_done)
  {
  	int error = 0;
  	char buffer[FILEIO_BUFSIZE];
  	ssize_t len = 0;
  
  	while (!error && (len = p_read(ifd, buffer, sizeof(buffer))) > 0)
  		/* p_write() does not have the same semantics as write().  It loops
  		 * internally and will return 0 when it has completed writing.
  		 */
  		error = p_write(ofd, buffer, len);
  
  	if (len < 0) {
  		git_error_set(GIT_ERROR_OS, "read error while copying file");
  		error = (int)len;
  	}
  
  	if (error < 0)
  		git_error_set(GIT_ERROR_OS, "write error while copying file");
  
  	if (close_fd_when_done) {
  		p_close(ifd);
  		p_close(ofd);
  	}
  
  	return error;
  }
  
  int git_futils_cp(const char *from, const char *to, mode_t filemode)
  {
  	int ifd, ofd;
  
  	if ((ifd = git_futils_open_ro(from)) < 0)
  		return ifd;
  
  	if ((ofd = p_open(to, O_WRONLY | O_CREAT | O_EXCL, filemode)) < 0) {
  		p_close(ifd);
  		return git_path_set_error(errno, to, "open for writing");
  	}
  
  	return cp_by_fd(ifd, ofd, true);
  }
  
  int git_futils_touch(const char *path, time_t *when)
  {
  	struct p_timeval times[2];
  	int ret;
  
  	times[0].tv_sec =  times[1].tv_sec  = when ? *when : time(NULL);
  	times[0].tv_usec = times[1].tv_usec = 0;
  
  	ret = p_utimes(path, times);
  
  	return (ret < 0) ? git_path_set_error(errno, path, "touch") : 0;
  }
  
  static int cp_link(const char *from, const char *to, size_t link_size)
  {
  	int error = 0;
  	ssize_t read_len;
  	char *link_data;
  	size_t alloc_size;
  
  	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_size, link_size, 1);
  	link_data = git__malloc(alloc_size);
  	GIT_ERROR_CHECK_ALLOC(link_data);
  
  	read_len = p_readlink(from, link_data, link_size);
  	if (read_len != (ssize_t)link_size) {
  		git_error_set(GIT_ERROR_OS, "failed to read symlink data for '%s'", from);
  		error = -1;
  	}
  	else {
  		link_data[read_len] = '\0';
  
  		if (p_symlink(link_data, to) < 0) {
  			git_error_set(GIT_ERROR_OS, "could not symlink '%s' as '%s'",
  				link_data, to);
  			error = -1;
  		}
  	}
  
  	git__free(link_data);
  	return error;
  }
  
  typedef struct {
  	const char *to_root;
  	git_buf to;
  	ssize_t from_prefix;
  	uint32_t flags;
  	uint32_t mkdir_flags;
  	mode_t dirmode;
  } cp_r_info;
  
  #define GIT_CPDIR__MKDIR_DONE_FOR_TO_ROOT (1u << 10)
  
  static int _cp_r_mkdir(cp_r_info *info, git_buf *from)
  {
  	int error = 0;
  
  	/* create root directory the first time we need to create a directory */
  	if ((info->flags & GIT_CPDIR__MKDIR_DONE_FOR_TO_ROOT) == 0) {
  		error = git_futils_mkdir(
  			info->to_root, info->dirmode,
  			(info->flags & GIT_CPDIR_CHMOD_DIRS) ? GIT_MKDIR_CHMOD : 0);
  
  		info->flags |= GIT_CPDIR__MKDIR_DONE_FOR_TO_ROOT;
  	}
  
  	/* create directory with root as base to prevent excess chmods */
  	if (!error)
  		error = git_futils_mkdir_relative(
  			from->ptr + info->from_prefix, info->to_root,
  			info->dirmode, info->mkdir_flags, NULL);
  
  	return error;
  }
  
  static int _cp_r_callback(void *ref, git_buf *from)
  {
  	int error = 0;
  	cp_r_info *info = ref;
  	struct stat from_st, to_st;
  	bool exists = false;
  
  	if ((info->flags & GIT_CPDIR_COPY_DOTFILES) == 0 &&
  		from->ptr[git_path_basename_offset(from)] == '.')
  		return 0;
  
  	if ((error = git_buf_joinpath(
  			&info->to, info->to_root, from->ptr + info->from_prefix)) < 0)
  		return error;
  
  	if (!(error = git_path_lstat(info->to.ptr, &to_st)))
  		exists = true;
  	else if (error != GIT_ENOTFOUND)
  		return error;
  	else {
  		git_error_clear();
  		error = 0;
  	}
  
  	if ((error = git_path_lstat(from->ptr, &from_st)) < 0)
  		return error;
  
  	if (S_ISDIR(from_st.st_mode)) {
  		mode_t oldmode = info->dirmode;
  
  		/* if we are not chmod'ing, then overwrite dirmode */
  		if ((info->flags & GIT_CPDIR_CHMOD_DIRS) == 0)
  			info->dirmode = from_st.st_mode;
  
  		/* make directory now if CREATE_EMPTY_DIRS is requested and needed */
  		if (!exists && (info->flags & GIT_CPDIR_CREATE_EMPTY_DIRS) != 0)
  			error = _cp_r_mkdir(info, from);
  
  		/* recurse onto target directory */
  		if (!error && (!exists || S_ISDIR(to_st.st_mode)))
  			error = git_path_direach(from, 0, _cp_r_callback, info);
  
  		if (oldmode != 0)
  			info->dirmode = oldmode;
  
  		return error;
  	}
  
  	if (exists) {
  		if ((info->flags & GIT_CPDIR_OVERWRITE) == 0)
  			return 0;
  
  		if (p_unlink(info->to.ptr) < 0) {
  			git_error_set(GIT_ERROR_OS, "cannot overwrite existing file '%s'",
  				info->to.ptr);
  			return GIT_EEXISTS;
  		}
  	}
  
  	/* Done if this isn't a regular file or a symlink */
  	if (!S_ISREG(from_st.st_mode) &&
  		(!S_ISLNK(from_st.st_mode) ||
  		 (info->flags & GIT_CPDIR_COPY_SYMLINKS) == 0))
  		return 0;
  
  	/* Make container directory on demand if needed */
  	if ((info->flags & GIT_CPDIR_CREATE_EMPTY_DIRS) == 0 &&
  		(error = _cp_r_mkdir(info, from)) < 0)
  		return error;
  
  	/* make symlink or regular file */
  	if (info->flags & GIT_CPDIR_LINK_FILES) {
  		if ((error = p_link(from->ptr, info->to.ptr)) < 0)
  			git_error_set(GIT_ERROR_OS, "failed to link '%s'", from->ptr);
  	} else if (S_ISLNK(from_st.st_mode)) {
  		error = cp_link(from->ptr, info->to.ptr, (size_t)from_st.st_size);
  	} else {
  		mode_t usemode = from_st.st_mode;
  
  		if ((info->flags & GIT_CPDIR_SIMPLE_TO_MODE) != 0)
  			usemode = GIT_PERMS_FOR_WRITE(usemode);
  
  		error = git_futils_cp(from->ptr, info->to.ptr, usemode);
  	}
  
  	return error;
  }
  
  int git_futils_cp_r(
  	const char *from,
  	const char *to,
  	uint32_t flags,
  	mode_t dirmode)
  {
  	int error;
  	git_buf path = GIT_BUF_INIT;
  	cp_r_info info;
  
  	if (git_buf_joinpath(&path, from, "") < 0) /* ensure trailing slash */
  		return -1;
  
  	memset(&info, 0, sizeof(info));
  	info.to_root = to;
  	info.flags   = flags;
  	info.dirmode = dirmode;
  	info.from_prefix = path.size;
  	git_buf_init(&info.to, 0);
  
  	/* precalculate mkdir flags */
  	if ((flags & GIT_CPDIR_CREATE_EMPTY_DIRS) == 0) {
  		/* if not creating empty dirs, then use mkdir to create the path on
  		 * demand right before files are copied.
  		 */
  		info.mkdir_flags = GIT_MKDIR_PATH | GIT_MKDIR_SKIP_LAST;
  		if ((flags & GIT_CPDIR_CHMOD_DIRS) != 0)
  			info.mkdir_flags |= GIT_MKDIR_CHMOD_PATH;
  	} else {
  		/* otherwise, we will do simple mkdir as directories are encountered */
  		info.mkdir_flags =
  			((flags & GIT_CPDIR_CHMOD_DIRS) != 0) ? GIT_MKDIR_CHMOD : 0;
  	}
  
  	error = _cp_r_callback(&info, &path);
  
  	git_buf_dispose(&path);
  	git_buf_dispose(&info.to);
  
  	return error;
  }
  
  int git_futils_filestamp_check(
  	git_futils_filestamp *stamp, const char *path)
  {
  	struct stat st;
  
  	/* if the stamp is NULL, then always reload */
  	if (stamp == NULL)
  		return 1;
  
  	if (p_stat(path, &st) < 0)
  		return GIT_ENOTFOUND;
  
  	if (stamp->mtime.tv_sec == st.st_mtime &&
  #if defined(GIT_USE_NSEC)
  		stamp->mtime.tv_nsec == st.st_mtime_nsec &&
  #endif
  		stamp->size  == (uint64_t)st.st_size   &&
  		stamp->ino   == (unsigned int)st.st_ino)
  		return 0;
  
  	stamp->mtime.tv_sec = st.st_mtime;
  #if defined(GIT_USE_NSEC)
  	stamp->mtime.tv_nsec = st.st_mtime_nsec;
  #endif
  	stamp->size  = (uint64_t)st.st_size;
  	stamp->ino   = (unsigned int)st.st_ino;
  
  	return 1;
  }
  
  void git_futils_filestamp_set(
  	git_futils_filestamp *target, const git_futils_filestamp *source)
  {
  	if (source)
  		memcpy(target, source, sizeof(*target));
  	else
  		memset(target, 0, sizeof(*target));
  }
  
  
  void git_futils_filestamp_set_from_stat(
  	git_futils_filestamp *stamp, struct stat *st)
  {
  	if (st) {
  		stamp->mtime.tv_sec = st->st_mtime;
  #if defined(GIT_USE_NSEC)
  		stamp->mtime.tv_nsec = st->st_mtime_nsec;
  #else
  		stamp->mtime.tv_nsec = 0;
  #endif
  		stamp->size  = (uint64_t)st->st_size;
  		stamp->ino   = (unsigned int)st->st_ino;
  	} else {
  		memset(stamp, 0, sizeof(*stamp));
  	}
  }
  
  int git_futils_fsync_dir(const char *path)
  {
  #ifdef GIT_WIN32
  	GIT_UNUSED(path);
  	return 0;
  #else
  	int fd, error = -1;
  
  	if ((fd = p_open(path, O_RDONLY)) < 0) {
  		git_error_set(GIT_ERROR_OS, "failed to open directory '%s' for fsync", path);
  		return -1;
  	}
  
  	if ((error = p_fsync(fd)) < 0)
  		git_error_set(GIT_ERROR_OS, "failed to fsync directory '%s'", path);
  
  	p_close(fd);
  	return error;
  #endif
  }
  
  int git_futils_fsync_parent(const char *path)
  {
  	char *parent;
  	int error;
  
  	if ((parent = git_path_dirname(path)) == NULL)
  		return -1;
  
  	error = git_futils_fsync_dir(parent);
  	git__free(parent);
  	return error;
  }
  

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