xref: /freebsd-14.2/lib/libc/sys/stat.2 (revision 00a91cb7)
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32.\"     @(#)stat.2	8.4 (Berkeley) 5/1/95
33.\" $FreeBSD$
34.\"
35.Dd February 15, 2002
36.Dt STAT 2
37.Os
38.Sh NAME
39.Nm stat ,
40.Nm lstat ,
41.Nm fstat
42.Nd get file status
43.Sh LIBRARY
44.Lb libc
45.Sh SYNOPSIS
46.In sys/types.h
47.In sys/stat.h
48.Ft int
49.Fn stat "const char *path" "struct stat *sb"
50.Ft int
51.Fn lstat "const char *path" "struct stat *sb"
52.Ft int
53.Fn fstat "int fd" "struct stat *sb"
54.Sh DESCRIPTION
55The
56.Fn stat
57function obtains information about the file pointed to by
58.Fa path .
59Read, write or execute
60permission of the named file is not required, but all directories
61listed in the path name leading to the file must be searchable.
62.Pp
63The
64.Fn lstat
65function is like
66.Fn stat
67except in the case where the named file is a symbolic link,
68in which case
69.Fn lstat
70returns information about the link,
71while
72.Fn stat
73returns information about the file the link references.
74.Pp
75The
76.Fn fstat
77function obtains the same information about an open file
78known by the file descriptor
79.Fa fd .
80.Pp
81The
82.Fa sb
83argument is a pointer to a
84.Vt stat
85structure
86as defined by
87.Aq Pa sys/stat.h
88(shown below)
89and into which information is placed concerning the file.
90.Bd -literal
91struct stat {
92    dev_t     st_dev;               /* inode's device */
93    ino_t     st_ino;               /* inode's number */
94    mode_t    st_mode;              /* inode protection mode */
95    nlink_t   st_nlink;             /* number of hard links */
96    uid_t     st_uid;               /* user ID of the file's owner */
97    gid_t     st_gid;               /* group ID of the file's group */
98    dev_t     st_rdev;              /* device type */
99#ifndef _POSIX_SOURCE
100    struct timespec st_atimespec;  /* time of last access */
101    struct timespec st_mtimespec;  /* time of last data modification */
102    struct timespec st_ctimespec;  /* time of last file status change */
103#else
104    time_t    st_atime;             /* time of last access */
105    long      st_atimensec;         /* nsec of last access */
106    time_t    st_mtime;             /* time of last data modification */
107    long      st_mtimensec;         /* nsec of last data modification */
108    time_t    st_ctime;             /* time of last file status change */
109    long      st_ctimensec;         /* nsec of last file status change */
110#endif
111    off_t     st_size;              /* file size, in bytes */
112    int64_t   st_blocks;            /* blocks allocated for file */
113    u_int32_t st_blksize;           /* optimal blocksize for I/O */
114    fflags_t  st_flags;             /* user defined flags for file */
115    u_int32_t st_gen;               /* file generation number */
116};
117.Ed
118.Pp
119The time-related fields of
120.Fa struct stat
121are as follows:
122.Bl -tag -width XXXst_mtime
123.It st_atime
124Time when file data last accessed.
125Changed by the
126.Xr mknod 2 ,
127.Xr utimes 2
128and
129.Xr read 2
130system calls.
131.It st_mtime
132Time when file data last modified.
133Changed by the
134.Xr mknod 2 ,
135.Xr utimes 2
136and
137.Xr write 2
138system calls.
139.It st_ctime
140Time when file status was last changed (inode data modification).
141Changed by the
142.Xr chmod 2 ,
143.Xr chown 2 ,
144.Xr link 2 ,
145.Xr mknod 2 ,
146.Xr rename 2 ,
147.Xr unlink 2 ,
148.Xr utimes 2
149and
150.Xr write 2
151system calls.
152.El
153.Pp
154If
155.Dv _POSIX_SOURCE
156is not defined, the time-related fields are defined as:
157.Bd -literal
158#ifndef _POSIX_SOURCE
159#define st_atime st_atimespec.tv_sec
160#define st_mtime st_mtimespec.tv_sec
161#define st_ctime st_ctimespec.tv_sec
162#endif
163.Ed
164.Pp
165The size-related fields of the
166.Fa struct stat
167are as follows:
168.Bl -tag -width XXXst_blksize
169.It st_blksize
170The optimal I/O block size for the file.
171.It st_blocks
172The actual number of blocks allocated for the file in 512-byte units.
173As short symbolic links are stored in the inode, this number may
174be zero.
175.El
176.Pp
177The status information word
178.Fa st_mode
179has the following bits:
180.Bd -literal
181#define S_IFMT   0170000  /* type of file */
182#define S_IFIFO  0010000  /* named pipe (fifo) */
183#define S_IFCHR  0020000  /* character special */
184#define S_IFDIR  0040000  /* directory */
185#define S_IFBLK  0060000  /* block special */
186#define S_IFREG  0100000  /* regular */
187#define S_IFLNK  0120000  /* symbolic link */
188#define S_IFSOCK 0140000  /* socket */
189#define S_IFWHT  0160000  /* whiteout */
190#define S_ISUID  0004000  /* set user id on execution */
191#define S_ISGID  0002000  /* set group id on execution */
192#define S_ISVTX  0001000  /* save swapped text even after use */
193#define S_IRUSR  0000400  /* read permission, owner */
194#define S_IWUSR  0000200  /* write permission, owner */
195#define S_IXUSR  0000100  /* execute/search permission, owner */
196.Ed
197.Pp
198For a list of access modes, see
199.Aq Pa sys/stat.h ,
200.Xr access 2
201and
202.Xr chmod 2 .
203.Sh RETURN VALUES
204.Rv -std
205.Sh COMPATIBILITY
206Previous versions of the system used different types for the
207.Li st_dev ,
208.Li st_uid ,
209.Li st_gid ,
210.Li st_rdev ,
211.Li st_size ,
212.Li st_blksize
213and
214.Li st_blocks
215fields.
216.Sh ERRORS
217The
218.Fn stat
219and
220.Fn lstat
221functions will fail if:
222.Bl -tag -width Er
223.It Bq Er EACCES
224Search permission is denied for a component of the path prefix.
225.It Bq Er EFAULT
226.Fa sb
227or
228.Em name
229points to an invalid address.
230.It Bq Er EIO
231An I/O error occurred while reading from or writing to the file system.
232.It Bq Er ELOOP
233Too many symbolic links were encountered in translating the pathname.
234.It Bq Er ENAMETOOLONG
235A component of a pathname exceeded 255 characters,
236or an entire path name exceeded 1023 characters.
237.It Bq Er ENOENT
238The named file does not exist.
239.It Bq Er ENOTDIR
240A component of the path prefix is not a directory.
241.It Bq Er EOVERFLOW
242The file size in bytes cannot be
243represented correctly in the structure pointed to by
244.Fa sb .
245.El
246.Pp
247.Bl -tag -width Er
248The
249.Fn fstat
250function will fail if:
251.It Bq Er EBADF
252.Fa fd
253is not a valid open file descriptor.
254.It Bq Er EFAULT
255.Fa sb
256points to an invalid address.
257.It Bq Er EIO
258An I/O error occurred while reading from or writing to the file system.
259.It Bq Er EOVERFLOW
260The file size in bytes cannot be
261represented correctly in the structure pointed to by
262.Fa sb .
263.El
264.Sh SEE ALSO
265.Xr access 2 ,
266.Xr chmod 2 ,
267.Xr chown 2 ,
268.Xr utimes 2 ,
269.Xr symlink 7
270.Sh BUGS
271Applying
272.Fn fstat
273to a socket (and thus to a pipe)
274returns a zeroed buffer,
275except for the blocksize field,
276and a unique device and inode number.
277.Sh STANDARDS
278The
279.Fn stat
280and
281.Fn fstat
282function calls are expected to conform to
283.St -p1003.1-90 .
284.Sh HISTORY
285A
286.Fn stat
287and a
288.Fn fstat
289function call appeared in
290.At v7 .
291A
292.Fn lstat
293function call appeared in
294.Bx 4.2 .
295