STAT(2) COMMAND REFERENCE STAT(2) NAME stat, lstat, fstat - get file status SYNOPSIS #include <sys/types.h> #include <sys/stat.h> stat(path, buf) char *path; struct stat *buf; lstat(path, buf) char *path; struct stat *buf; fstat(fd, buf) int fd; struct stat *buf; DESCRIPTION The command stat obtains information about the file 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 reachable. The lstat command is like stat except in the case where the named file is a symbolic link, in which case lstat returns information about the link, while stat returns information about the file the link references. The command fstat obtains the same information about an open file referenced by fd, such as would be obtained by an open call. A pointer buf points to a stat structure into which information is placed concerning the file; the structure is defined in <sys/stat.h> as: struct stat { dev_t st_dev; /* ID of device containing a directory /* entry for this file */ ino_t st_ino; /* this inode's number */ u_short st_mode; /* file mode; see below */ short st_nlink; /* number of hard links to the file */ short st_uid; /* user ID of the file's owner */ short st_gid; /* group ID of the file's group */ dev_t st_rdev; /* ID of device -- this entry is /* defined only */ /* for character special or block /* special files */ off_t st_size; /* total size of file */ time_t st_atime; /* time of last access */ Printed 4/6/89 1
STAT(2) COMMAND REFERENCE STAT(2) int st_spare1; time_t st_mtime; /* time of last data modification */ int st_spare2; time_t st_ctime; /* time of last file status change */ int st_spare3; long st_blksize; /* optimal blocksize for file system /* I/O ops */ long st_blocks; /* actual number of blocks allocated */ long st_spare4[2]; }; st_atime Time when file data was last read or modified by the system calls mknod(2), utimes(2), and read(2). st_atime is not set when a directory is searched. st_mtime Time when file data was last modified by the system calls mknod(2), utimes(2), and write(2). st_mtime is not set by changes of owner, group, link count, or mode. st_ctime Time when file status was last modified by both writing and changing the inode with the system calls chmod(2), chown(2), link(2), mknod(2), rename(2), unlink(2), utimes(2), and write(2). The status information word st_mode has these bits: #define S_IFMT 0170000 /* type of file */ #define S_IFDIR 0040000 /* directory */ #define S_IFCHR 0020000 /* character special */ #define S_IFBLK 0060000 /* block special */ #define S_IFREG 0100000 /* regular */ #define S_IFLNK 0120000 /* symbolic link */ #define S_IFSOCK 0140000 /* socket */ #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_IREAD 0000400 /* read permission, owner */ #define S_IWRITE 0000200 /* write permission, owner */ #define S_IEXEC 0000100 /* execute/search permission, owner */ The mode bits 0000070 and 0000007 encode group and others permissions (see chmod(2)). When fd is associated with a pipe, fstat reports an ordinary file with an inode number, restricted permissions, and a not necessarily meaningful length. DIAGNOSTICS The commands stat and lstat fail if one or more of the Printed 4/6/89 2
STAT(2) COMMAND REFERENCE STAT(2) following are true: [ENOTDIR] A component of the path prefix is not a directory. [ENOASCII] The path name contains a character with the high-order bit set. [ENAMETOOLONG] The path name is too long. [ENOENT] The named file does not exist. [EFAULT] Buf or path points to an invalid address. [ELOOP] Too many symbolic links were encountered in translating the path name. [EIO] An I/O error occurred while reading from or writing to the file system. The fstat command fails if one of the following are true: [EBADF] Fd is not a valid open file descriptor. [EIO] An I/O error occurred while reading from or writing to the file system. RETURN VALUE Upon successful completion a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error. Caveats The fields in the stat structure currently marked st_spare1, st_spare2, and st_spare3 are present in preparation for inode time stamps expanding to 64 bits. This, however, can break certain programs which depend on the time stamps being contiguous (in calls to utimes(2)). Applying fstat to a socket returns a zeroed buffer. See Also chmod(2), chown(2), and utimes(2). Printed 4/6/89 3
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