[RFC PATCH 2/5] fs: Add xgetdents system call and xreaddir file operation
From: Abhi Das
Date: Fri Jul 25 2014 - 13:39:45 EST
Also add linux_xdirent structure that will be the container for
dirent, stat and xattr info.
Signed-off-by: Abhi Das <adas@xxxxxxxxxx>
---
arch/x86/syscalls/syscall_32.tbl | 1 +
arch/x86/syscalls/syscall_64.tbl | 1 +
fs/readdir.c | 42 ++++++++++++++++++++++++++++++++++++++++
fs/stat.c | 4 +++-
include/linux/fs.h | 1 +
include/linux/stat.h | 2 ++
include/uapi/linux/stat.h | 33 +++++++++++++++++++++++++++++++
7 files changed, 83 insertions(+), 1 deletion(-)
diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
index 6d6ca37..35723e3 100644
--- a/arch/x86/syscalls/syscall_32.tbl
+++ b/arch/x86/syscalls/syscall_32.tbl
@@ -362,3 +362,4 @@
353 i386 renameat2 sys_renameat2
354 i386 xstat sys_xstat
355 i386 fxstat sys_fxstat
+356 i386 xgetdents sys_xgetdents
diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
index 1308ee3..566aab1 100644
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -325,6 +325,7 @@
316 common renameat2 sys_renameat2
317 common xstat sys_xstat
318 common fxstat sys_fxstat
+319 common xgetdents sys_xgetdents
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/readdir.c b/fs/readdir.c
index 33fd922..d676088 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -224,6 +224,48 @@ SYSCALL_DEFINE3(getdents, unsigned int, fd,
return error;
}
+SYSCALL_DEFINE5(xgetdents, unsigned int, fd, unsigned, flags, unsigned int, mask,
+ void __user *, buf, unsigned int, count)
+{
+ struct fd f;
+ struct inode *inode;
+ int error = -ENOTDIR;
+
+ if (!count)
+ return -EINVAL;
+
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+
+ inode = f.file->f_path.dentry->d_inode;
+
+ error = -ENOTSUPP;
+ if (!f.file->f_op || !f.file->f_op->xreaddir)
+ goto out;
+
+ error = security_file_permission(f.file, MAY_READ);
+ if (error)
+ goto out;
+
+ error = mutex_lock_killable(&inode->i_mutex);
+ if (error)
+ goto out;
+
+ error = -ENOENT;
+ if (!IS_DEADDIR(inode)) {
+ error = f.file->f_op->xreaddir(f.file, flags, mask, buf, count);
+ file_accessed(f.file);
+ }
+ mutex_unlock(&inode->i_mutex);
+out:
+ fdput(f);
+ return error;
+}
+
struct getdents_callback64 {
struct dir_context ctx;
struct linux_dirent64 __user * current_dir;
diff --git a/fs/stat.c b/fs/stat.c
index 1fd0b3e..db45f8b 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -651,7 +651,7 @@ static int xstat_get_params(unsigned int mask, struct xstat __user *buffer,
* Otherwise we copy the extended stats to userspace and return the amount of
* data written into the buffer (or -EFAULT).
*/
-static long xstat_set_result(struct kstat *stat, struct xstat __user *buffer)
+long xstat_set_result(struct kstat *stat, struct xstat __user *buffer)
{
u32 mask = stat->result_mask, gran = stat->tv_granularity;
@@ -701,6 +701,8 @@ static long xstat_set_result(struct kstat *stat, struct xstat __user *buffer)
return 0;
}
+EXPORT_SYMBOL(xstat_set_result);
+
/*
* System call to get extended stats by path
*/
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b91f235..79c7d39 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1464,6 +1464,7 @@ struct file_operations {
ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
int (*iterate) (struct file *, struct dir_context *);
+ size_t (*xreaddir) (struct file *, unsigned int, unsigned int, void __user *, size_t);
unsigned int (*poll) (struct file *, struct poll_table_struct *);
long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
diff --git a/include/linux/stat.h b/include/linux/stat.h
index 552e047..75be415 100644
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -46,4 +46,6 @@ struct kstat {
unsigned char volume_id[16]; /* volume identifier */
};
+long xstat_set_result(struct kstat *stat, struct xstat __user *buffer);
+
#endif
diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
index 2907352..d7ea6c5 100644
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -90,6 +90,14 @@
#define XSTAT_VOLUME_ID 0x00008000U /* want/got st_volume_id */
#define XSTAT_ALL_STATS 0x0000ffffU /* all supported stats */
+/* xattr request flags */
+#define XSTAT_XATTR_USER 0x00010000U /* user.* xattrs */
+#define XSTAT_XATTR_SYSTEM 0x00020000U /* system.* xattrs */
+#define XSTAT_XATTR_SECURITY 0x00040000U /* security.* xattrs */
+#define XSTAT_XATTR_POSIX_ACL 0x00080000U /* posix acl xattrs */
+#define XSTAT_XATTR_ALL 0x00ff0000U /* all xattrs */
+#define XSTAT_XATTR_VALUES 0x01000000U /* retrieve values along with keys */
+
/*
* Extended stat structures
*/
@@ -152,4 +160,29 @@ struct xstat {
#define XSTAT_INFO_SYSTEM 0x00001000U /* File is marked system (DOS+) */
#define XSTAT_INFO_ARCHIVE 0x00002000U /* File is marked archive (DOS+) */
+struct xdirent_xattr {
+ size_t xa_value_len; /* length of value field */
+ char xa_name_val[1]; /* name/value pair, name is NULL terminated and
+ * value is xa_value_len in length */
+};
+
+/*
+ * xb_blob: first contains NULL terminated name, followed by struct xdirent_xattr
+ * objects packed together.
+ */
+struct xdirent_blob {
+ unsigned int xb_xattr_count;
+ char xb_blob[1]; /* contains variable length data like
+ * NULL-terminated name, xattrs etc */
+};
+
+struct linux_xdirent {
+ unsigned long xd_ino;
+ char xd_type;
+ unsigned long xd_off;
+ struct xstat xd_stat;
+ unsigned long xd_reclen;
+ struct xdirent_blob xd_blob;
+};
+
#endif /* _UAPI_LINUX_STAT_H */
--
1.8.1.4
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