Source / Include Folder (#88)

Moved Source Files Into `src` Folder

1 files changed, 376 insertions, 0 deletions

diff --git a/src/stat.c b/src/stat.c
new file mode 100644
index 0000000..47e60b6
--- /dev/null
+++ b/src/stat.c
@@ -0,0 +1,376 @@
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2018-2019 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+#include "stat.h"
+#include "util.h"
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#if BFS_HAS_SYS_PARAM
+#	include <sys/param.h>
+#endif
+
+#ifdef STATX_BASIC_STATS
+#	define HAVE_STATX true
+#elif __linux__
+#	include <linux/stat.h>
+#	include <sys/syscall.h>
+#	include <unistd.h>
+#endif
+
+#if HAVE_STATX || defined(__NR_statx)
+#	define HAVE_BFS_STATX true
+#endif
+
+#if __APPLE__
+#	define st_atim st_atimespec
+#	define st_ctim st_ctimespec
+#	define st_mtim st_mtimespec
+#	define st_birthtim st_birthtimespec
+#endif
+
+const char *bfs_stat_field_name(enum bfs_stat_field field) {
+	switch (field) {
+	case BFS_STAT_DEV:
+		return "device number";
+	case BFS_STAT_INO:
+		return "inode nunmber";
+	case BFS_STAT_TYPE:
+		return "type";
+	case BFS_STAT_MODE:
+		return "mode";
+	case BFS_STAT_NLINK:
+		return "link count";
+	case BFS_STAT_GID:
+		return "group ID";
+	case BFS_STAT_UID:
+		return "user ID";
+	case BFS_STAT_SIZE:
+		return "size";
+	case BFS_STAT_BLOCKS:
+		return "block count";
+	case BFS_STAT_RDEV:
+		return "underlying device";
+	case BFS_STAT_ATTRS:
+		return "attributes";
+	case BFS_STAT_ATIME:
+		return "access time";
+	case BFS_STAT_BTIME:
+		return "birth time";
+	case BFS_STAT_CTIME:
+		return "change time";
+	case BFS_STAT_MTIME:
+		return "modification time";
+	}
+
+	assert(!"Unrecognized stat field");
+	return "???";
+}
+
+/**
+ * Check if we should retry a failed stat() due to a potentially broken link.
+ */
+static bool bfs_stat_retry(int ret, enum bfs_stat_flags flags) {
+	return ret != 0
+		&& (flags & (BFS_STAT_NOFOLLOW | BFS_STAT_TRYFOLLOW)) == BFS_STAT_TRYFOLLOW
+		&& is_nonexistence_error(errno);
+}
+
+/**
+ * Convert a struct stat to a struct bfs_stat.
+ */
+static void bfs_stat_convert(const struct stat *statbuf, struct bfs_stat *buf) {
+	buf->mask = 0;
+
+	buf->dev = statbuf->st_dev;
+	buf->mask |= BFS_STAT_DEV;
+
+	buf->ino = statbuf->st_ino;
+	buf->mask |= BFS_STAT_INO;
+
+	buf->mode = statbuf->st_mode;
+	buf->mask |= BFS_STAT_TYPE | BFS_STAT_MODE;
+
+	buf->nlink = statbuf->st_nlink;
+	buf->mask |= BFS_STAT_NLINK;
+
+	buf->gid = statbuf->st_gid;
+	buf->mask |= BFS_STAT_GID;
+
+	buf->uid = statbuf->st_uid;
+	buf->mask |= BFS_STAT_UID;
+
+	buf->size = statbuf->st_size;
+	buf->mask |= BFS_STAT_SIZE;
+
+	buf->blocks = statbuf->st_blocks;
+	buf->mask |= BFS_STAT_BLOCKS;
+
+	buf->rdev = statbuf->st_rdev;
+	buf->mask |= BFS_STAT_RDEV;
+
+#if BSD
+	buf->attrs = statbuf->st_flags;
+	buf->mask |= BFS_STAT_ATTRS;
+#endif
+
+	buf->atime = statbuf->st_atim;
+	buf->mask |= BFS_STAT_ATIME;
+
+	buf->ctime = statbuf->st_ctim;
+	buf->mask |= BFS_STAT_CTIME;
+
+	buf->mtime = statbuf->st_mtim;
+	buf->mask |= BFS_STAT_MTIME;
+
+#if __APPLE__ || __FreeBSD__ || __NetBSD__
+	buf->btime = statbuf->st_birthtim;
+	buf->mask |= BFS_STAT_BTIME;
+#endif
+}
+
+/**
+ * bfs_stat() implementation backed by stat().
+ */
+static int bfs_stat_impl(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flags flags, struct bfs_stat *buf) {
+	struct stat statbuf;
+	int ret = fstatat(at_fd, at_path, &statbuf, at_flags);
+
+	if (bfs_stat_retry(ret, flags)) {
+		at_flags |= AT_SYMLINK_NOFOLLOW;
+		ret = fstatat(at_fd, at_path, &statbuf, at_flags);
+	}
+
+	if (ret == 0) {
+		bfs_stat_convert(&statbuf, buf);
+	}
+
+	return ret;
+}
+
+#if HAVE_BFS_STATX
+
+/**
+ * Wrapper for the statx() system call, which had no glibc wrapper prior to 2.28.
+ */
+static int bfs_statx(int at_fd, const char *at_path, int at_flags, unsigned int mask, struct statx *buf) {
+#if BFS_HAS_FEATURE(memory_sanitizer, false)
+	// -fsanitize=memory doesn't know about statx(), so tell it the memory
+	// got initialized
+	memset(buf, 0, sizeof(*buf));
+#endif
+
+#if HAVE_STATX
+	return statx(at_fd, at_path, at_flags, mask, buf);
+#else
+	return syscall(__NR_statx, at_fd, at_path, at_flags, mask, buf);
+#endif
+}
+
+/**
+ * bfs_stat() implementation backed by statx().
+ */
+static int bfs_statx_impl(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flags flags, struct bfs_stat *buf) {
+	unsigned int mask = STATX_BASIC_STATS | STATX_BTIME;
+	struct statx xbuf;
+	int ret = bfs_statx(at_fd, at_path, at_flags, mask, &xbuf);
+
+	if (bfs_stat_retry(ret, flags)) {
+		at_flags |= AT_SYMLINK_NOFOLLOW;
+		ret = bfs_statx(at_fd, at_path, at_flags, mask, &xbuf);
+	}
+
+	if (ret != 0) {
+		return ret;
+	}
+
+	// Callers shouldn't have to check anything except the times
+	const unsigned int guaranteed = STATX_BASIC_STATS ^ (STATX_ATIME | STATX_CTIME | STATX_MTIME);
+	if ((xbuf.stx_mask & guaranteed) != guaranteed) {
+		errno = ENOTSUP;
+		return -1;
+	}
+
+	buf->mask = 0;
+
+	buf->dev = bfs_makedev(xbuf.stx_dev_major, xbuf.stx_dev_minor);
+	buf->mask |= BFS_STAT_DEV;
+
+	if (xbuf.stx_mask & STATX_INO) {
+		buf->ino = xbuf.stx_ino;
+		buf->mask |= BFS_STAT_INO;
+	}
+
+	buf->mode = xbuf.stx_mode;
+	if (xbuf.stx_mask & STATX_TYPE) {
+		buf->mask |= BFS_STAT_TYPE;
+	}
+	if (xbuf.stx_mask & STATX_MODE) {
+		buf->mask |= BFS_STAT_MODE;
+	}
+
+	if (xbuf.stx_mask & STATX_NLINK) {
+		buf->nlink = xbuf.stx_nlink;
+		buf->mask |= BFS_STAT_NLINK;
+	}
+
+	if (xbuf.stx_mask & STATX_GID) {
+		buf->gid = xbuf.stx_gid;
+		buf->mask |= BFS_STAT_GID;
+	}
+
+	if (xbuf.stx_mask & STATX_UID) {
+		buf->uid = xbuf.stx_uid;
+		buf->mask |= BFS_STAT_UID;
+	}
+
+	if (xbuf.stx_mask & STATX_SIZE) {
+		buf->size = xbuf.stx_size;
+		buf->mask |= BFS_STAT_SIZE;
+	}
+
+	if (xbuf.stx_mask & STATX_BLOCKS) {
+		buf->blocks = xbuf.stx_blocks;
+		buf->mask |= BFS_STAT_BLOCKS;
+	}
+
+	buf->rdev = bfs_makedev(xbuf.stx_rdev_major, xbuf.stx_rdev_minor);
+	buf->mask |= BFS_STAT_RDEV;
+
+	buf->attrs = xbuf.stx_attributes;
+	buf->mask |= BFS_STAT_ATTRS;
+
+	if (xbuf.stx_mask & STATX_ATIME) {
+		buf->atime.tv_sec = xbuf.stx_atime.tv_sec;
+		buf->atime.tv_nsec = xbuf.stx_atime.tv_nsec;
+		buf->mask |= BFS_STAT_ATIME;
+	}
+
+	if (xbuf.stx_mask & STATX_BTIME) {
+		buf->btime.tv_sec = xbuf.stx_btime.tv_sec;
+		buf->btime.tv_nsec = xbuf.stx_btime.tv_nsec;
+		buf->mask |= BFS_STAT_BTIME;
+	}
+
+	if (xbuf.stx_mask & STATX_CTIME) {
+		buf->ctime.tv_sec = xbuf.stx_ctime.tv_sec;
+		buf->ctime.tv_nsec = xbuf.stx_ctime.tv_nsec;
+		buf->mask |= BFS_STAT_CTIME;
+	}
+
+	if (xbuf.stx_mask & STATX_MTIME) {
+		buf->mtime.tv_sec = xbuf.stx_mtime.tv_sec;
+		buf->mtime.tv_nsec = xbuf.stx_mtime.tv_nsec;
+		buf->mask |= BFS_STAT_MTIME;
+	}
+
+	return ret;
+}
+
+#endif // HAVE_BFS_STATX
+
+/**
+ * Allows calling stat with custom at_flags.
+ */
+static int bfs_stat_explicit(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flags flags, struct bfs_stat *buf) {
+#if HAVE_BFS_STATX
+	static bool has_statx = true;
+
+	if (has_statx) {
+		int ret = bfs_statx_impl(at_fd, at_path, at_flags, flags, buf);
+		// EPERM is commonly returned in a seccomp() sandbox that does
+		// not allow statx()
+		if (ret != 0 && (errno == ENOSYS || errno == EPERM)) {
+			has_statx = false;
+		} else {
+			return ret;
+		}
+	}
+#endif
+
+	return bfs_stat_impl(at_fd, at_path, at_flags, flags, buf);
+}
+
+int bfs_stat(int at_fd, const char *at_path, enum bfs_stat_flags flags, struct bfs_stat *buf) {
+	int at_flags = 0;
+	if (flags & BFS_STAT_NOFOLLOW) {
+		at_flags |= AT_SYMLINK_NOFOLLOW;
+	}
+
+#ifdef AT_STATX_DONT_SYNC
+	if (flags & BFS_STAT_NOSYNC) {
+		at_flags |= AT_STATX_DONT_SYNC;
+	}
+#endif
+
+	if (at_path) {
+		return bfs_stat_explicit(at_fd, at_path, at_flags, flags, buf);
+	}
+
+	// Check __GNU__ to work around https://lists.gnu.org/archive/html/bug-hurd/2021-12/msg00001.html
+#if defined(AT_EMPTY_PATH) && !__GNU__
+	static bool has_at_ep = true;
+	if (has_at_ep) {
+		at_flags |= AT_EMPTY_PATH;
+		int ret = bfs_stat_explicit(at_fd, "", at_flags, flags, buf);
+		if (ret != 0 && errno == EINVAL) {
+			has_at_ep = false;
+		} else {
+			return ret;
+		}
+	}
+#endif
+
+	struct stat statbuf;
+	if (fstat(at_fd, &statbuf) == 0) {
+		bfs_stat_convert(&statbuf, buf);
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
+const struct timespec *bfs_stat_time(const struct bfs_stat *buf, enum bfs_stat_field field) {
+	if (!(buf->mask & field)) {
+		errno = ENOTSUP;
+		return NULL;
+	}
+
+	switch (field) {
+	case BFS_STAT_ATIME:
+		return &buf->atime;
+	case BFS_STAT_BTIME:
+		return &buf->btime;
+	case BFS_STAT_CTIME:
+		return &buf->ctime;
+	case BFS_STAT_MTIME:
+		return &buf->mtime;
+	default:
+		assert(!"Invalid stat field for time");
+		errno = EINVAL;
+		return NULL;
+	}
+}
+
+void bfs_stat_id(const struct bfs_stat *buf, bfs_file_id *id) {
+	memcpy(*id, &buf->dev, sizeof(buf->dev));
+	memcpy(*id + sizeof(buf->dev), &buf->ino, sizeof(buf->ino));
+}