xnu-2782.30.5.tar.gz

[apple/xnu.git] / bsd / man / man2 / stat.2

diff --git a/bsd/man/man2/stat.2 b/bsd/man/man2/stat.2
index 04f63c7ba8706496737afb393c39855414f24383..e9acf874f1716401c65f814e2646b5a3c7975a13 100644 (file)
--- a/bsd/man/man2/stat.2
+++ b/bsd/man/man2/stat.2
@@ -33,47 +33,83 @@
 .\"
 .\"     @(#)stat.2     8.3 (Berkeley) 4/19/94
 .\"
 .\"
 .\"     @(#)stat.2     8.3 (Berkeley) 4/19/94
 .\"

-.Dd April 19, 1994
+.Dd May 15, 2008

 .Dt STAT 2
 .Os BSD 4
 .Sh NAME
 .Dt STAT 2
 .Os BSD 4
 .Sh NAME

-.Nm stat ,
+.Nm fstat ,
+.Nm fstat64 ,

 .Nm lstat ,
 .Nm lstat ,

-.Nm fstat
+.Nm lstat64 ,
+.Nm stat ,
+.Nm stat64 ,
+.Nm fstatat

 .Nd get file status
 .Sh SYNOPSIS
 .Nd get file status
 .Sh SYNOPSIS

-.Fd #include <sys/types.h>

 .Fd #include <sys/stat.h>
 .Ft int
 .Fd #include <sys/stat.h>
 .Ft int

-.Fn stat "const char *path" "struct stat *sb"
+.Fo fstat
+.Fa "int fildes"
+.Fa "struct stat *buf"
+.Fc
+.Ft int
+.Fo lstat
+.Fa "const char *restrict path"
+.Fa "struct stat *restrict buf"
+.Fc
+.Ft int
+.Fo stat
+.Fa "const char *restrict path"
+.Fa "struct stat *restrict buf"
+.Fc
+.Ft int
+.Fn fstatat "int fd" "const char *path" "struct stat *buf" "int flag"
+.Sh TRANSITIIONAL SYNOPSIS (NOW DEPRECATED)
+.Ft int
+.br
+.Fo fstat64
+.Fa "int fildes"
+.Fa "struct stat64 *buf"
+.Fc ;
+.sp

 .Ft int
 .Ft int

-.Fn lstat "const char *path" "struct stat *sb"
+.br
+.Fo lstat64
+.Fa "const char *restrict path"
+.Fa "struct stat64 *restrict buf"
+.Fc ;
+.sp

 .Ft int
 .Ft int

-.Fn fstat "int fd" "struct stat *sb"
+.br
+.Fo stat64
+.Fa "const char *restrict path"
+.Fa "struct stat64 *restrict buf"
+.Fc ;

 .Sh DESCRIPTION
 .Sh DESCRIPTION

-The
-.Fn stat
+The 
+.Fn stat 

 function obtains information about the file pointed to by
 .Fa path .
 Read, write or execute
 permission of the named file is not required, but all directories
 listed in the path name leading to the file must be searchable.
 .Pp
 function obtains information about the file pointed to by
 .Fa path .
 Read, write or execute
 permission of the named file is not required, but all directories
 listed in the path name leading to the file must be searchable.
 .Pp

-.Fn Lstat
+The
+.Fn lstat
+function

 is like
 .Fn stat
 is like
 .Fn stat

-except in the case where the named file is a symbolic link,
-in which case
+except in the case where the named file is a symbolic link;

 .Fn lstat
 returns information about the link,
 while
 .Fn stat
 returns information about the file the link references.
 Unlike other filesystem objects,
 .Fn lstat
 returns information about the link,
 while
 .Fn stat
 returns information about the file the link references.
 Unlike other filesystem objects,

-symbolic links do not have an owner, group, access mode, times, etc.
-Instead, these attributes are taken from the directory that
+symbolic links may not have an owner, group, access mode, times, etc.
+Instead, these attributes may be taken from the directory that

 contains the link.
 contains the link.

-The only attributes returned from an
+In this case, the only attributes returned from an

 .Fn lstat
 that refer to the symbolic link itself are the file type (S_IFLNK),
 size, blocks, and link count (always 1).
 .Fn lstat
 that refer to the symbolic link itself are the file type (S_IFLNK),
 size, blocks, and link count (always 1).


@@ -82,23 +118,69 @@ The
 .Fn fstat
 obtains the same information about an open file
 known by the file descriptor
 .Fn fstat
 obtains the same information about an open file
 known by the file descriptor

-.Fa fd .
+.Fa fildes .

 .Pp
 The
 .Pp
 The

-.Fa sb
-argument is a pointer to a
+.Fn fstatat
+system call is equivalent to

 .Fn stat
 .Fn stat

-structure
+and
+.Fn lstat
+except in the case where the
+.Fa path
+specifies a relative path.
+In this case the status is retrieved from a file relative to
+the directory associated with the file descriptor
+.Fa fd
+instead of the current working directory.
+.Pp
+The values for the
+.Fa flag
+are constructed by a bitwise-inclusive OR of flags from the following list,
+defined in
+.In fcntl.h :
+.Bl -tag -width indent
+.It Dv AT_SYMLINK_NOFOLLOW
+If
+.Fa path
+names a symbolic link, the status of the symbolic link is returned.
+.El
+.Pp
+If
+.Fn fstatat
+is passed the special value
+.Dv AT_FDCWD
+in the
+.Fa fd
+parameter, the current working directory is used and the behavior is
+identical to a call to
+.Fn stat
+or
+.Fn lstat
+respectively, depending on whether or not the
+.Dv AT_SYMLINK_NOFOLLOW
+bit is set in
+.Fa flag .
+.Pp
+The
+.Fa buf
+argument is a pointer to a
+.Fa stat
+structure 

 as defined by
 .Aq Pa sys/stat.h
 as defined by
 .Aq Pa sys/stat.h

-(shown below)

 and into which information is placed concerning the file.
 and into which information is placed concerning the file.

+When the macro
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+is not defined (see below for more information about this macro), the
+.Fa stat
+structure is defined as:

 .Bd -literal
 .Bd -literal

-struct stat {
+struct stat { /* when _DARWIN_FEATURE_64_BIT_INODE is NOT defined */

     dev_t    st_dev;    /* device inode resides on */
     ino_t    st_ino;    /* inode's number */
     mode_t   st_mode;   /* inode protection mode */
     dev_t    st_dev;    /* device inode resides on */
     ino_t    st_ino;    /* inode's number */
     mode_t   st_mode;   /* inode protection mode */

-    nlink_t  st_nlink;  /* number or hard links to the file */
+    nlink_t  st_nlink;  /* number of hard links to the file */

     uid_t    st_uid;    /* user-id of owner */
     gid_t    st_gid;    /* group-id of owner */
     dev_t    st_rdev;   /* device type, for special file inode */
     uid_t    st_uid;    /* user-id of owner */
     gid_t    st_gid;    /* group-id of owner */
     dev_t    st_rdev;   /* device type, for special file inode */


@@ -113,10 +195,38 @@ struct stat {
 };
 .Ed
 .Pp
 };
 .Ed
 .Pp

+However, when the macro
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+is defined, the
+.Fa stat
+structure will now be defined as:
+.Bd -literal
+struct stat { /* when _DARWIN_FEATURE_64_BIT_INODE is defined */
+    dev_t           st_dev;           /* ID of device containing file */
+    mode_t          st_mode;          /* Mode of file (see below) */
+    nlink_t         st_nlink;         /* Number of hard links */
+    ino_t          st_ino;           /* File serial number */
+    uid_t           st_uid;           /* User ID of the file */
+    gid_t           st_gid;           /* Group ID of the file */
+    dev_t           st_rdev;          /* Device ID */
+    struct timespec st_atimespec;     /* time of last access */
+    struct timespec st_mtimespec;     /* time of last data modification */
+    struct timespec st_ctimespec;     /* time of last status change */
+    struct timespec st_birthtimespec; /* time of file creation(birth) */
+    off_t           st_size;          /* file size, in bytes */
+    blkcnt_t        st_blocks;        /* blocks allocated for file */
+    blksize_t       st_blksize;       /* optimal blocksize for I/O */
+    uint32_t        st_flags;         /* user defined flags for file */
+    uint32_t        st_gen;           /* file generation number */
+    int32_t         st_lspare;        /* RESERVED: DO NOT USE! */
+    int64_t         st_qspare[2];     /* RESERVED: DO NOT USE! */
+};
+.Ed
+.Pp

 The time-related fields of
 .Fa struct stat
 are as follows:
 The time-related fields of
 .Fa struct stat
 are as follows:

-.Bl -tag -width XXXst_mtime
+.Bl -tag -width XXXst_birthtime

 .It st_atime
 Time when file data last accessed.
 Changed by the
 .It st_atime
 Time when file data last accessed.
 Changed by the


@@ -146,11 +256,15 @@ Changed by the
 and
 .Xr write 2
 system calls.
 and
 .Xr write 2
 system calls.

+.It st_birthtime
+Time of file creation. Only set once when the file is created. This field is 
+only available in the 64 bit inode variants. On filesystems where birthtime is 
+not available, this field holds the
+.Fa ctime
+instead.

 .El
 .Pp
 .El
 .Pp

-The size-related fields of the
-.Fa struct stat
-are as follows:
+The size-related fields of the structures are as follows:

 .Bl -tag -width XXXst_blksize
 .It st_blksize
 The optimal I/O block size for the file.
 .Bl -tag -width XXXst_blksize
 .It st_blksize
 The optimal I/O block size for the file.


@@ -186,6 +300,148 @@ For a list of access modes, see
 .Xr access 2
 and
 .Xr chmod 2 .
 .Xr access 2
 and
 .Xr chmod 2 .

+.Pp
+For a list of the file flags in the
+.Fa st_flags
+field, see
+.Aq Pa sys/stat.h
+and
+.Xr chflags 2 .
+.Sh _DARWIN_FEATURE_64_BIT_INODE
+In order to accommodate advanced capabilities of newer file systems, the 
+.Fa struct stat ,
+.Fa struct statfs ,
+and
+.Fa struct dirent
+data structures were updated in Mac OSX 10.5.
+.Pp
+The most obvious change is the increased size of
+.Fa ino_t
+from 32 bits to 64 bits.  As a consequence, storing an ino_t in an int is
+no longer safe, and file formats storing ino_t as 32-bit values may need to
+be updated.  There are other changes as well, such as the widening of
+.Fa f_fstypename ,
+.Fa f_mntonname ,
+and
+.Fa f_mntfromname
+in
+.Fa struct statfs .
+Please refer to
+.Xr stat 2
+and
+.Xr dir 5
+for more detail on the specific changes to the other affected data structures.
+.Pp
+On platforms that existed before these updates were available, ABI
+compatibility is achieved by providing two implementations for related
+functions: one using the legacy data structures and one using the updated
+data structures.  Variants which make use of the newer structures have their
+symbols suffixed with $INODE64.  These $INODE64 suffixes are automatically
+appended by the compiler tool-chain and should not be used directly.
+.Pp
+Platforms that were released after these updates only have the newer variants
+available to them.  These platforms have the macro
+.Dv _DARWIN_FEATURE_ONLY_64_BIT_INODE
+defined.
+.Pp
+The
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+macro should not be set directly.  Instead, developers should make use of the
+.Dv _DARWIN_NO_64_BIT_INODE
+or
+.Dv _DARWIN_USE_64_BIT_INODE
+macros when the default variant is not desired.  The following table details
+the effects of defining these macros for different deployment targets.
+.Pp
+.TS
+center;
+c s s s
+l | c s s
+c | c c c
+c | c c c
+l | c c c.
+T{
+.Dv _DARWIN_FEATURE_ONLY_64_BIT_INODE Sy not defined
+T}
+=
+       Deployment Target
+user defines:  < 10.5  10.5    > 10.5
+_
+T{
+.Em (none)
+T}     32-bit  32-bit  64-bit
+T{
+.Dv _DARWIN_NO_64_BIT_INODE
+T}     32-bit  32-bit  32-bit
+T{
+.Dv _DARWIN_USE_64_BIT_INODE
+T}     32-bit  64-bit  64-bit
+_
+.T&
+c s s s
+c s s s
+c | l s s
+c | c c c
+l | c c c.
+
+T{
+.Dv _DARWIN_FEATURE_ONLY_64_BIT_INODE Sy defined
+T}
+=
+user defines:  Any Deployment Target
+_
+T{
+.Em (none)
+T}     64-bit-only
+T{
+.Dv _DARWIN_NO_64_BIT_INODE
+T}     T{
+.Em (error)
+T}
+T{
+.Dv _DARWIN_USE_64_BIT_INODE
+T}     64-bit-only
+_
+.TE
+.Pp
+.Bl -tag -width 64-bit-only -offset indent
+.It 32-bit
+32-bit inode values are enabled, and the legacy structures involving the
+.Vt ino_t
+type are in use.
+The macro
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+is not defined.
+.It 64-bit
+64-bit inode values are enabled, and the expanded structures involving the
+.Vt ino_t
+type are in use.
+The macro
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+is defined, and loader symbols will contain the
+.Li $INODE64
+suffix.
+.It 64-bit-only
+Like 64-bit, except loader symbols do not have the
+.Li $INODE64
+suffix.
+.It Em (error)
+A compile time error is generated.
+.El
+.Pp
+Due to the increased benefits of the larger structure, it is highly
+recommended that developers not define
+.Dv _DARWIN_NO_64_BIT_INODE
+and make use of
+.Dv _DARWIN_USE_64_BIT_INODE
+when targeting Mac OSX 10.5.
+.Pp
+In addition to the $INODE64 suffixed symbols, variants suffixed with 64 are
+also available for related functions.  These functions were provided as a way
+for developers to use the updated structures in code that also made use of
+the legacy structures.  The enlarged stat structures were also prefixed with
+64 to distinguish them from their legacy variants.  These functions have been
+deprecated and should be avoided.

 .Sh RETURN VALUES
 Upon successful completion a value of 0 is returned.
 Otherwise, a value of -1 is returned and
 .Sh RETURN VALUES
 Upon successful completion a value of 0 is returned.
 Otherwise, a value of -1 is returned and


@@ -203,45 +459,103 @@ and
 .Li st_blocks
 fields.
 .Sh ERRORS
 .Li st_blocks
 fields.
 .Sh ERRORS

-.Fn Stat
-and
+.Bl -tag -width Er
+The
+.Fn fstat
+system call will fail if:
+.\" ===========
+.It Bq Er EBADF
+.Fa fildes
+is not a valid open file descriptor.
+.\" ===========
+.It Bq Er EFAULT
+.Fa Sb
+points to an invalid address.
+.\" ===========
+.It Bq Er EIO
+An I/O error occurs while reading from or writing to the file system.
+.El
+.Pp
+The

 .Fn lstat
 .Fn lstat

-will fail if:
+and
+.Fn stat
+system calls will fail if:

 .Bl -tag -width Er
 .Bl -tag -width Er

-.It Bq Er ENOTDIR
-A component of the path prefix is not a directory.
-.It Bq Er ENAMETOOLONG
-A component of a pathname exceeded 
-.Dv {NAME_MAX}
-characters, or an entire path name exceeded 
-.Dv {PATH_MAX}
-characters.
-.It Bq Er ENOENT
-The named file does not exist.
+.\" ===========

 .It Bq Er EACCES
 Search permission is denied for a component of the path prefix.
 .It Bq Er EACCES
 Search permission is denied for a component of the path prefix.

-.It Bq Er ELOOP
-Too many symbolic links were encountered in translating the pathname.
+.\" ===========

 .It Bq Er EFAULT
 .Fa Sb
 or
 .Em name
 points to an invalid address.
 .It Bq Er EFAULT
 .Fa Sb
 or
 .Em name
 points to an invalid address.

+.\" ===========

 .It Bq Er EIO
 .It Bq Er EIO

-An I/O error occurred while reading from or writing to the file system.
+An I/O error occurs while reading from or writing to the file system.
+.\" ===========
+.It Bq Er ELOOP
+Too many symbolic links are encountered in translating the pathname.
+This is taken to be indicative of a looping symbolic link.
+.\" ===========
+.It Bq Er ENAMETOOLONG
+A component of a pathname exceeds
+.Dv {NAME_MAX}
+characters, or an entire path name exceeds
+.Dv {PATH_MAX}
+characters.
+.\" ===========
+.It Bq Er ENOENT
+The named file does not exist.
+.\" ===========
+.It Bq Er ENOTDIR
+A component of the path prefix is not a directory.
+.El
+.Pp
+The
+.Fn fstat ,
+.Fn lstat ,
+and
+.Fn stat
+system calls will fail if:
+.Bl -tag -width Er
+.\" ===========
+.It Bq Er EOVERFLOW
+The file size in bytes 
+or the number of blocks allocated to the file
+or the file serial number cannot be represented correctly
+in the structure pointed to by
+.Fa buf .

 .El
 .Pp
 .El
 .Pp

+In addition to the errors returned by the
+.Fn stat
+and
+.Fn lstat ,
+.Fn fstatat
+may fail if:

 .Bl -tag -width Er
 .Bl -tag -width Er

-.Fn Fstat
-will fail if:

 .It Bq Er EBADF
 .It Bq Er EBADF

+The
+.Fa path
+argument does not specify an absolute path and the

 .Fa fd
 .Fa fd

-is not a valid open file descriptor.
-.It Bq Er EFAULT
-.Fa Sb
-points to an invalid address.
-.It Bq Er EIO
-An I/O error occurred while reading from or writing to the file system.
+argument is neither
+.Dv AT_FDCWD
+nor a valid file descriptor open for searching.
+.It Bq Er EINVAL
+The value of the
+.Fa flag
+argument is not valid.
+.It Bq Er ENOTDIR
+The
+.Fa path
+argument is not an absolute path and
+.Fa fd
+is neither
+.Dv AT_FDCWD
+nor a file descriptor associated with a directory.

 .El
 .Sh CAVEATS
 The file generation number,
 .El
 .Sh CAVEATS
 The file generation number,


@@ -257,10 +571,32 @@ are present in preparation for inode time stamps expanding
 to 64 bits.  This, however, can break certain programs that
 depend on the time stamps being contiguous (in calls to
 .Xr utimes 2 ) .
 to 64 bits.  This, however, can break certain programs that
 depend on the time stamps being contiguous (in calls to
 .Xr utimes 2 ) .

+.Sh TRANSITIONAL DESCRIPTION (NOW DEPRECATED)
+The
+.Fa fstat64 ,
+.Fa lstat64
+and
+.Fa stat64
+routines are equivalent to their corresponding non-64-suffixed routine,
+when 64-bit inodes are in effect.
+They were added before there was support for the symbol variants, and so are
+now deprecated.
+Instead of using these, set the
+.Dv _DARWIN_USE_64_BIT_INODE
+macro before including header files to force 64-bit inode support.
+.Pp
+The
+.Fa stat64
+structure used by these deprecated routines is the same as the
+.Fa stat
+structure when 64-bit inodes are in effect (see above).

 .Sh SEE ALSO
 .Sh SEE ALSO

+.Xr chflags 2 ,

 .Xr chmod 2 ,
 .Xr chown 2 ,
 .Xr chmod 2 ,
 .Xr chown 2 ,

-.Xr utimes 2
+.Xr utimes 2 ,
+.Xr compat 5 ,
+.Xr statfs 2 ,

 .Xr symlink 7
 .Sh BUGS
 Applying
 .Xr symlink 7
 .Sh BUGS
 Applying


@@ -276,8 +612,21 @@ and
 .Fn fstat
 function calls are expected to conform to 
 .St -p1003.1-88 .
 .Fn fstat
 function calls are expected to conform to 
 .St -p1003.1-88 .

+The
+.Fn fstatat
+system call is expected to conform to POSIX.1-2008 .

 .Sh HISTORY
 An
 .Fn lstat
 function call appeared in
 .Bx 4.2 .
 .Sh HISTORY
 An
 .Fn lstat
 function call appeared in
 .Bx 4.2 .

+The 
+.Fn stat64 ,
+.Fn fstat64 ,
+and
+.Fn lstat64
+system calls first appeared in Mac OS X 10.5 (Leopard) and are now deprecated
+in favor of the corresponding symbol variants.
+The
+.Fn fstatat
+system call appeared in OS X 10.10