STAT(2)                   NetBSD System Calls Manual                   STAT(2)

NAME
     stat, lstat, fstat -- get file status

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/stat.h>

     int
     stat(const char *path, struct stat *sb);

     int
     lstat(const char *path, struct stat *sb);

     int
     fstat(int fd, struct stat *sb);

DESCRIPTION
     The stat() function obtains information about the file pointed to by
     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.

     lstat() is like stat() except in the case where the named file is a sym-
     bolic link, in which case lstat() returns information about the link,
     while stat() returns information about the file the link references.

     The fstat() function obtains the same information about an open file
     known by the file descriptor fd.

     The sb argument is a pointer to a stat structure as defined by
     <sys/stat.h> (shown below) and into which information is placed concern-
     ing the file.

     struct stat {
         dev_t     st_dev;     /* device containing the file */
         ino_t     st_ino;     /* file's serial number */
         mode_t    st_mode;    /* file's mode (protection and type) */
         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 device special file */
     #if defined(_NETBSD_SOURCE)
         struct timespec st_atimespec;  /* time of last access */
         struct timespec st_mtimespec;  /* time of last data modification */
         struct timespec st_ctimespec;  /* time of last file status change */
     #else
         time_t    st_atime;            /* time of last access */
         long      st_atimensec;        /* nsec of last access */
         time_t    st_mtime;            /* time of last data modification */
         long      st_mtimensec;        /* nsec of last data modification */
         time_t    st_ctime;            /* time of last file status change */
         long      st_ctimensec;        /* nsec of last file status change */
     #endif
         off_t     st_size;    /* file size, in bytes */
         blkcnt_t  st_blocks;  /* blocks allocated for file */
         blksize_t st_blksize; /* optimal file sys I/O ops blocksize */
         uint32_t st_flags;   /* user defined flags for file */
         uint32_t st_gen;     /* file generation number */
     #if defined(_NETBSD_SOURCE)
         struct timespec st_birthtimespec;   /* time of inode creation */
     #else
         time_t    st_birthtime;             /* time of inode creation */
         long      st_birthtimensec;         /* nsec of inode creation */
     #endif
     };

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

     st_atime         Time when file data was last accessed.  Changed by the
                      mknod(2), utimes(2) and read(2) system calls.

     st_mtime         Time when file data was last modified.  Changed by the
                      mknod(2), utimes(2) and write(2) system calls.

     st_ctime         Time when file status was last changed (file metadata
                      modification).  Changed by the chflags(2), chmod(2),
                      chown(2), link(2), mknod(2), rename(2), unlink(2),
                      utimes(2) and write(2) system calls.

     st_birthtime     Time when the inode was created.

     If _NETBSD_SOURCE is defined, the time-related fields are defined as:

     #if defined(_NETBSD_SOURCE)
     #define st_atime                st_atimespec.tv_sec
     #define st_atimensec            st_atimespec.tv_nsec
     #define st_mtime                st_mtimespec.tv_sec
     #define st_mtimensec            st_mtimespec.tv_nsec
     #define st_ctime                st_ctimespec.tv_sec
     #define st_ctimensec            st_ctimespec.tv_nsec
     #define st_birthtime            st_birthtimespec.tv_sec
     #define st_birthtimensec        st_birthtimespec.tv_nsec
     #endif

     The size-related fields of the struct stat are as follows:

     st_size        The size of the file in bytes.  A directory will be a mul-
                    tiple of the size of the dirent(5) structure.  Some
                    filesystems (notably ZFS) return the number of enties in
                    the directory instead of the size in bytes.

     st_blksize     The optimal I/O block size for the file.

     st_blocks      The actual number of blocks allocated for the file in
                    512-byte units.  As short symbolic links are stored in the
                    inode, this number may be zero.

     The status information word st_mode has the following bits:

     #define S_IFMT 0170000           /* type of file */
     #define        S_IFIFO  0010000  /* named pipe (fifo) */
     #define        S_IFCHR  0020000  /* character special */
     #define        S_IFDIR  0040000  /* directory */
     #define        S_IFBLK  0060000  /* block special */
     #define        S_IFREG  0100000  /* regular */
     #define        S_IFLNK  0120000  /* symbolic link */
     #define        S_IFSOCK 0140000  /* socket */
     #define        S_IFWHT  0160000  /* whiteout */
     #define S_ISUID 0004000  /* set user id on execution */
     #define S_ISGID 0002000  /* set group id on execution */
     #define S_ISVTX 0001000  /* save swapped text even after use */
     #define S_IRUSR 0000400  /* read permission, owner */
     #define S_IWUSR 0000200  /* write permission, owner */
     #define S_IXUSR 0000100  /* execute/search permission, owner */
     #define S_IRGRP 0000040  /* read permission, group */
     #define S_IWGRP 0000020  /* write permission, group */
     #define S_IXGRP 0000010  /* execute/search permission, group */
     #define S_IROTH 0000004  /* read permission, other */
     #define S_IWOTH 0000002  /* write permission, other */
     #define S_IXOTH 0000001  /* execute/search permission, other */

     For a list of access modes, see <sys/stat.h>, access(2) and chmod(2).

     The status information word st_flags has the following bits:

     #define UF_NODUMP       0x00000001 /* do not dump file */
     #define UF_IMMUTABLE    0x00000002 /* file may not be changed */
     #define UF_APPEND       0x00000004 /* writes to file may only append */
     #define UF_OPAQUE       0x00000008 /* directory is opaque wrt. union */
     #define SF_ARCHIVED     0x00010000 /* file is archived */
     #define SF_IMMUTABLE    0x00020000 /* file may not be changed */
     #define SF_APPEND       0x00040000 /* writes to file may only append */

     For a description of the flags, see chflags(2).

RETURN VALUES
     Upon successful completion a value of 0 is returned.  Otherwise, a value
     of -1 is returned and errno is set to indicate the error.

COMPATIBILITY
     Previous versions of the system used different types for the st_dev,
     st_uid, st_gid, st_rdev, st_size, st_blksize and st_blocks fields.

ERRORS
     stat() and lstat() will fail if:

     [ENOTDIR]          A component of the path prefix is not a directory.

     [ENAMETOOLONG]     A component of a pathname exceeded {NAME_MAX} charac-
                        ters, or an entire path name exceeded {PATH_MAX} char-
                        acters.

     [ENOENT]           The named file does not exist.

     [EACCES]           Search permission is denied for a component of the
                        path prefix.

     [ELOOP]            Too many symbolic links were encountered in translat-
                        ing the pathname.

     [EFAULT]           sb or name points to an invalid address.

     [ENXIO]            The named file is a character special or block special
                        file, and the device associated with this special file
                        does not exist.

     [EIO]              An I/O error occurred while reading from or writing to
                        the file system.

     [EBADF]            A badly formed v-node was encountered.  This can hap-
                        pen if a file system information node is incorrect.

     fstat() will fail if:

     [EBADF]            fd is not a valid open file descriptor.

     [EFAULT]           sb points to an invalid address.

     [EIO]              An I/O error occurred while reading from or writing to
                        the file system.

SEE ALSO
     chflags(2), chmod(2), chown(2), utimes(2), dir(5), symlink(7)

STANDARDS
     The stat() and fstat() functions conform to ISO/IEC 9945-1:1990
     (``POSIX.1'').

HISTORY
     A lstat() function call appeared in 4.2BSD.

BUGS
     Applying fstat() to a socket (and thus to a pipe) returns a zero'd
     buffer, except for the blocksize field, and a unique device and file
     serial number.

NetBSD 5.0_STABLE                June 9, 2007                NetBSD 5.0_STABLE
