STAT(2) STAT(2) NAME stat, lstat, fstat - get file status SYNOPSIS #include #include 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 _S_t_a_t obtains information about the file _p_a_t_h. 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. _L_s_t_a_t is like _s_t_a_t except in the case where the named file is a sym‐ bolic link, in which case _l_s_t_a_t returns information about the link, while _s_t_a_t returns information about the file the link references. _F_s_t_a_t obtains the same information about an open file referenced by the argument descriptor, such as would be obtained by an _o_p_e_n call. _B_u_f is a pointer to a _s_t_a_t structure into which information is placed concerning the file. The contents of the structure pointed to by _b_u_f struct stat { dev_t st_dev; /* device inode resides on */ ino_t st_ino; /* this inode’s number */ u_short st_mode;/* protection */ short st_nlink;/* number or hard links to the file */ short st_uid; /* user-id of owner */ short st_gid; /* group-id of owner */ dev_t st_rdev;/* the device type, for inode that is device */ off_t st_size;/* total size of file */ time_t st_atime;/* file last access time */ int st_spare1; time_t st_mtime;/* file last modify time */ int st_spare2; time_t st_ctime;/* file last status change time */ 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. Changed by the following system calls: _m_k_n_o_d(2), _u_t_i_m_e_s(2), _r_e_a_d(2), and _w_r_i_t_e(2). For reasons of efficiency, st_atime is not set when a directory is searched, although this would be more logical. st_mtime Time when data was last modified. It is not set by changes of owner, group, link count, or mode. Changed by the following system calls: _m_k_n_o_d(2), _u_t_i_m_e_s(2), _w_r_i_t_e(2). st_ctime Time when file status was last changed. It is set both both by writing and changing the i-node. Changed by the following system calls: _c_h_m_o_d(2) _c_h_o_w_n(2), _l_i_n_k(2), _m_k_n_o_d(2), _r_e_n_a_m_e(2), _u_n_l_i_n_k(2), _u_t_i_m_e_s(2), _w_r_i_t_e(2). The status information word _s_t__m_o_d_e has 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 _c_h_m_o_d(2)). RETURN VALUE Upon successful completion a value of 0 is returned. Otherwise, a value of -1 is returned and _e_r_r_n_o is set to indicate the error. ERRORS _S_t_a_t and _l_s_t_a_t will fail if one or more of the following are true: [ENOTDIR] A component of the path prefix is not a directory. [EINVAL] The pathname contains a character with the high-order bit set. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [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 translating the pathname. [EFAULT] _B_u_f or _n_a_m_e points to an invalid address. [EIO] An I/O error occurred while reading from or writing to the file system. _F_s_t_a_t will fail if one or both of the following are true: [EBADF] _F_i_l_d_e_s is not a valid open file descriptor. [EFAULT] _B_u_f points to an invalid address. [EIO] An I/O error occurred while reading from or writing to the file system. CAVEAT The fields in the stat structure currently marked _s_t__s_p_a_r_e_1, _s_t__s_p_a_r_e_2, and _s_t__s_p_a_r_e_3 are present in preparation for inode time stamps expand‐ ing to 64 bits. This, however, can break certain programs that depend on the time stamps being contiguous (in calls to _u_t_i_m_e_s(2)). SEE ALSO chmod(2), chown(2), utimes(2) BUGS Applying _f_s_t_a_t to a socket (and thus to a pipe) returns a zero’d buffer, except for the blocksize field, and a unique device and inode number. 4th Berkeley Distribution May 12, 1986 STAT(2)