futils.c

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Author : 0xferrous
Date : 2026-07-18 07:15:39
Hash : c6ba959e
Message : mmap: use private mappings for read-only files Read-only mappings do not require shared semantics. Some filesystems, including virtiofs and GPFS, reject MAP_SHARED mappings with ENODEV while allowing MAP_PRIVATE mappings. Use GIT_MAP_PRIVATE for the read-only mapping helper and when reading pack headers. This also matches the behavior of native Git. Keep the writable Windows indexer mapping shared, since writes made through that mapping must reach the underlying file. Add a test that verifies the read-only mapping helper creates a private mapping. Refs #7136
src/util/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 "hash.h"
#include "rand.h"
#include "hashmap_str.h"

#include <ctype.h>

#define GIT_FILEMODE_DEFAULT 0100666

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_str *path_out, const char *filename, mode_t mode)
{
	const int open_flags = O_RDWR | O_CREAT | O_EXCL | O_BINARY | O_CLOEXEC;
	unsigned int tries = 32;
	int fd;

	while (tries--) {
		uint64_t rand = git_rand_next();

		git_str_sets(path_out, filename);
		git_str_puts(path_out, "_git2_");
		git_str_encode_hexstr(path_out, (void *)&rand, sizeof(uint64_t));

		if (git_str_oom(path_out))
			return -1;

		/* Note that we open with O_CREAT | O_EXCL */
		if ((fd = p_open(path_out->ptr, open_flags, mode)) >= 0)
			return fd;
	}

	git_error_set(GIT_ERROR_OS,
		"failed to create temporary file '%s'", path_out->ptr);
	git_str_dispose(path_out);
	return -1;
}

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_fs_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_fs_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_str *buf, git_file fd, size_t len)
{
	ssize_t read_size = 0;
	size_t alloc_len;

	git_str_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_str_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 < 0) {
		git_error_set(GIT_ERROR_OS, "failed to read descriptor");
		git_str_dispose(buf);
		return -1;
	}

	if ((size_t)read_size != len) {
		git_error_set(GIT_ERROR_FILESYSTEM, "could not read (expected %" PRIuZ " bytes, read %" PRIuZ ")", len, (size_t)read_size);
		git_str_dispose(buf);
		return -1;
	}

	buf->ptr[read_size] = '\0';
	buf->size = read_size;

	return 0;
}

int git_futils_readbuffer_fd_full(git_str *buf, git_file fd)
{
	static size_t blocksize = 10240;
	size_t alloc_len = 0, total_size = 0;
	ssize_t read_size = 0;

	git_str_clear(buf);

	while (true) {
		GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, blocksize);

		if (git_str_grow(buf, alloc_len) < 0)
			return -1;

		/* p_read loops internally to read blocksize bytes */
		read_size = p_read(fd, buf->ptr, blocksize);

		if (read_size < 0) {
			git_error_set(GIT_ERROR_OS, "failed to read descriptor");
			git_str_dispose(buf);
			return -1;
		}

		total_size += read_size;

		if ((size_t)read_size < blocksize) {
			break;
		}
	}

	buf->ptr[total_size] = '\0';
	buf->size = total_size;

	return 0;
}

int git_futils_readbuffer_updated(
	git_str *out,
	const char *path,
	unsigned char checksum[GIT_HASH_SHA256_SIZE],
	int *updated)
{
	int error;
	git_file fd;
	struct stat st;
	git_str buf = GIT_STR_INIT;
	unsigned char checksum_new[GIT_HASH_SHA256_SIZE];

	GIT_ASSERT_ARG(out);
	GIT_ASSERT_ARG(path && *path);

	if (updated != NULL)
		*updated = 0;

	if (p_stat(path, &st) < 0)
		return git_fs_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) {
		error = git_hash_buf(checksum_new, buf.ptr,
		                     buf.size, GIT_HASH_ALGORITHM_SHA256);

		if (error < 0) {
			git_str_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_SHA256_SIZE)) {
			git_str_dispose(&buf);
			if (updated)
				*updated = 0;

			return 0;
		}

		memcpy(checksum, checksum_new, GIT_HASH_SHA256_SIZE);
	}

	/*
	 * If we're here, the file did change, or the user didn't have an old version
	 */
	if (updated != NULL)
		*updated = 1;

	git_str_swap(out, &buf);
	git_str_dispose(&buf);

	return 0;
}

int git_futils_readbuffer(git_str *buf, const char *path)
{
	return git_futils_readbuffer_updated(buf, path, NULL, NULL);
}

int git_futils_writebuffer(
	const git_str *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_DEFAULT;

	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_str_cstr(buf), git_str_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_PRIVATE, 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_str *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_fs_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_fs_path_dirname_r(path, path->ptr);
		flags |= GIT_MKDIR_SKIP_LAST;
	}
	if ((flags & GIT_MKDIR_SKIP_LAST) != 0) {
		git_fs_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_str_clear(path);

	return 0;
}

int git_futils_mkdir(
	const char *path,
	mode_t mode,
	uint32_t flags)
{
	git_str make_path = GIT_STR_INIT, parent_path = GIT_STR_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_str_puts(&make_path, path)) < 0 ||
		(error = mkdir_canonicalize(&make_path, flags)) < 0 ||
		(error = git_str_puts(&parent_path, make_path.ptr)) < 0 ||
		make_path.size == 0)
		goto done;

	root_len = git_fs_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_fs_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_str_dispose(&make_path);
	git_str_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_str make_path = GIT_STR_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_fs_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_str_rfind(&make_path, '/');

	/* advance root past drive name or network mount prefix */
	min_root_len = git_fs_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->cache_pathset &&
		    git_hashset_str_contains(opts->cache_pathset, 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->cache_pathset && opts->cache_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->cache_pool, alloc_size);
			GIT_ERROR_CHECK_ALLOC(cache_path);

			memcpy(cache_path, make_path.ptr, make_path.size + 1);

			if ((error = git_hashset_str_add(opts->cache_pathset, 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_str_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_str *path, const char *ceiling)
{
	int error = GIT_ENOTFOUND;
	struct stat st;

	while (error == GIT_ENOTFOUND) {
		git_str_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_str *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_fs_path_set_error(errno, path->ptr, "rmdir");
	}

	else if (S_ISDIR(st.st_mode)) {
		data->depth++;

		error = git_fs_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_fs_path_set_error(errno, path->ptr, "rmdir");
		}
	}

	else if ((data->flags & GIT_RMDIR_REMOVE_FILES) != 0) {
		if (p_unlink(path->ptr) < 0)
			error = git_fs_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_fs_path_set_error(errno, path, "rmdir");
		} else if (en == ENOTEMPTY || en == EEXIST || en == EBUSY) {
			error = GIT_ITEROVER;
		} else {
			error = git_fs_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_str fullpath = GIT_STR_INIT;
	futils__rmdir_data data;

	/* build path and find "root" where we should start calling mkdir */
	if (git_fs_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_fs_path_walk_up(
			&fullpath, base, futils__rmdir_empty_parent, &data);

	if (error == GIT_ITEROVER) {
		git_error_clear();
		error = 0;
	}

	git_str_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[GIT_BUFSIZE_FILEIO];
	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_fs_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_fs_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_str 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_str *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_str *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_fs_path_basename_offset(from)] == '.')
		return 0;

	if ((error = git_str_joinpath(
			&info->to, info->to_root, from->ptr + info->from_prefix)) < 0)
		return error;

	if (!(error = git_fs_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_fs_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_fs_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_str path = GIT_STR_INIT;
	cp_r_info info;

	if (git_str_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_str_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_str_dispose(&path);
	git_str_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_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_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_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_fs_path_dirname(path)) == NULL)
		return -1;

	error = git_futils_fsync_dir(parent);
	git__free(parent);
	return error;
}
kc3-lang/libgit2/src/util/futils.c

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