1stat(2) System Calls stat(2)
2
6 stat, lstat, fstat, fstatat - get file status
7
9 #include <fcntl.h>
10 #include <sys/types.h>
11 #include <sys/stat.h>
12 int stat(const char *restrict path, struct stat *restrict buf);
14 int lstat(const char *restrict path, struct stat *restrict buf);
17 int fstat(int fildes, struct stat *buf);
20 int fstatat(int fildes, const char *path, struct stat *buf,
23 int flag);
24
27 The stat() function obtains information about the file pointed to by
28 path. Read, write, or execute permission of the named file is not
29 required, but all directories listed in the path name leading to the
30 file must be searchable.
31 The lstat() function obtains file attributes similar to stat(), except
34 when the named file is a symbolic link; in that case lstat() returns
35 information about the link, while stat() returns information about the
36 file the link references.
37 The fstat() function obtains information about an open file known by
40 the file descriptor fildes, obtained from a successful open(2),
41 creat(2), dup(2), fcntl(2), or pipe(2) function. If fildes references a
42 shared memory object, the system updates in the stat structure pointed
43 to by the buf argument only the st_uid, st_gid, st_size, and st_mode
44 fields, and only the S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and
45 S_IWOTH file permission bits need be valid. The system can update other
46 fields and flags. The fstat() function updates any pending time-related
47 fields before writing to the stat structure.
48 The fstatat() function obtains file attributes similar to the stat(),
51 lstat(), and fstat() functions. If the path argument is a relative
52 path, it is resolved relative to the fildes argument rather than the
53 current working directory. If path is absolute, the fildes argument is
54 unused. If the fildes argument has the special value AT_FDCWD, rela‐
55 tive paths are resolved from the current working directory. If AT_SYM‐
56 LINK_NOFOLLOW is set in the flag argument, the function behaves like
57 lstat() and does not automatically follow symbolic links. See
58 fsattr(5). If _ATTR_TRIGGER is set in the flag argument and the vnode
59 is a trigger mount point, the mount is performed and the function
60 returns the attributes of the root of the mounted filesystem.
61 The buf argument is a pointer to a stat structure into which informa‐
64 tion is placed concerning the file. A stat structure includes the fol‐
65 lowing members:
66 mode_t st_mode; /* File mode (see mknod(2)) */
68 ino_t st_ino; /* Inode number */
69 dev_t st_dev; /* ID of device containing */
70 /* a directory entry for this file */
71 dev_t st_rdev; /* ID of device */
72 /* This entry is defined only for */
73 /* char special or block special files */
74 nlink_t st_nlink; /* Number of links */
75 uid_t st_uid; /* User ID of the file's owner */
76 gid_t st_gid; /* Group ID of the file's group */
77 off_t st_size; /* File size in bytes */
78 time_t st_atime; /* Time of last access */
79 time_t st_mtime; /* Time of last data modification */
80 time_t st_ctime; /* Time of last file status change */
81 /* Times measured in seconds since */
82 /* 00:00:00 UTC, Jan. 1, 1970 */
83 long st_blksize; /* Preferred I/O block size */
84 blkcnt_t st_blocks; /* Number of 512 byte blocks allocated*/
85 char st_fstype[_ST_FSTYPSZ];
86 /* Null-terminated type of filesystem */
87 Descriptions of structure members are as follows:
91 st_mode The mode of the file as described for the mknod() func‐
93 tion. In addition to the modes described on the mknod(2)
94 manual page, the mode of a file can also be S_IFSOCK if
95 the file is a socket, S_IFDOOR if the file is a door,
96 S_IFPORT if the file is an event port, or S_IFLNK if the
97 file is a symbolic link. S_IFLNK can be returned either
98 by lstat() or by fstat() when the AT_SYMLINK_NOFOLLOW
99 flag is set.
100 st_ino This field uniquely identifies the file in a given file
103 system. The pair st_ino and st_dev uniquely identifies
104 regular files.
105 st_dev This field uniquely identifies the file system that con‐
108 tains the file. Its value may be used as input to the
109 ustat() function to determine more information about this
110 file system. No other meaning is associated with this
111 value.
112 st_rdev This field should be used only by administrative com‐
115 mands. It is valid only for block special or character
116 special files and only has meaning on the system where
117 the file was configured.
118 st_nlink This field should be used only by administrative com‐
121 mands.
122 st_uid The user ID of the file's owner.
125 st_gid The group ID of the file's group.
128 st_size For regular files, this is the address of the end of the
131 file. For block special or character special, this is not
132 defined. See also pipe(2).
133 st_atime Time when file data was last accessed. Some of the func‐
136 tions that change this member are: creat(), mknod(),
137 pipe(), utime(2), and read(2).
138 st_mtime Time when data was last modified. Some of the functions
141 that change this member are: creat(), mknod(), pipe(),
142 utime(), and write(2).
143 st_ctime Time when file status was last changed. Some of the func‐
146 tions that change this member are: chmod(2), chown(2),
147 creat(2), link(2), mknod(2), pipe(2), rename(2),
148 unlink(2), utime(2), and write(2).
149 st_blksize A hint as to the "best" unit size for I/O operations.
152 This field is not defined for block special or character
153 special files.
154 st_blocks The total number of physical blocks of size 512 bytes
157 actually allocated on disk. This field is not defined for
158 block special or character special files.
159 st_fstype A null-teminated string that uniquely identifies the type
162 of the filesystem that contains the file.
163
166 Upon successful completion, 0 is returned. Otherwise, −1 is returned
167 and errno is set to indicate the error.
168
170 The stat(), fstat(), lstat(), and fstatat() functions will fail if:
171 EIO An error occurred while reading from the file system.
173 EOVERFLOW The file size in bytes or the number of blocks allocated
176 to the file or the file serial number cannot be repre‐
177 sented correctly in the structure pointed to by buf.
178 The stat(), lstat(), and fstatat() functions will fail if:
182 EACCES Search permission is denied for a component of the path
184 prefix.
185 EFAULT The buf or path argument points to an illegal address.
188 EINTR A signal was caught during the execution of the stat()
191 or lstat() function.
192 ELOOP A loop exists in symbolic links encountered during the
195 resolution of the path argument.
196 ENAMETOOLONG The length of the path argument exceeds {PATH_MAX}, or
199 the length of a path component exceeds {NAME_MAX} while
200 _POSIX_NO_TRUNC is in effect.
201 ENOENT A component of path does not name an existing file or
204 path is an empty string.
205 ENOLINK The path argument points to a remote machine and the
208 link to that machine is no longer active.
209 ENOTDIR A component of the path prefix is not a directory, or
212 the fildes argument does not refer to a valid directory
213 when given a non-null relative path.
214 The fstat() and fstatat() functions will fail if:
218 EBADF The fildes argument is not a valid open file descriptor. The
220 fildes argument to fstatat() can also have the valid value
221 of AT_FDCWD.
222 EFAULT The buf argument points to an illegal address.
225 EINTR A signal was caught during the execution of the fstat()
228 function.
229 ENOLINK The fildes argument points to a remote machine and the link
232 to that machine is no longer active.
233 The stat(), fstat(), and lstat() functions may fail if:
237 EOVERFLOW One of the members is too large to store in the stat
239 structure pointed to by buf.
240 The stat() and lstat() functions may fail if:
244 ELOOP More than {SYMLOOP_MAX} symbolic links were encountered
246 during the resolution of the path argument.
247 ENAMETOOLONG As a result of encountering a symbolic link in resolu‐
250 tion of thepath argument, the length of the substituted
251 pathname strings exceeds {PATH_MAX}.
252 The stat() and fstatat() functions may fail if:
256 ENXIO The path argument names a character or block device special
258 file and the corresponding I/O device has been retired by the
259 fault management framework.
260
263 Example 1 Use stat() to obtain file status information.
264 The following example shows how to obtain file status information for a
267 file named /home/cnd/mod1. The structure variable buffer is defined for
268 the stat structure.
269 #include <sys/types.h>
272 #include <sys/stat.h>
273 #include <fcntl.h>
274 struct stat buffer;
275 int status;
276 ...
277 status = stat("/home/cnd/mod1", &buffer);
278 Example 2 Use stat() to get directory information.
281 The following example fragment gets status information for each entry
284 in a directory. The call to the stat() function stores file information
285 in the stat structure pointed to by statbuf. The lines that follow the
286 stat() call format the fields in the stat structure for presentation to
287 the user of the program.
288 #include <sys/types.h>
291 #include <sys/stat.h>
292 #include <dirent.h>
293 #include <pwd.h>
294 #include <grp.h>
295 #include <time.h>
296 #include <locale.h>
297 #include <langinfo.h>
298 #include <stdio.h>
299 #include <stdint.h>
300 struct dirent *dp;
301 struct stat statbuf;
302 struct passwd *pwd;
303 struct group *grp;
304 struct tm *tm;
305 char datestring[256];
306 ...
307 /* Loop through directory entries */
308 while ((dp = readdir(dir)) != NULL) {
309 /* Get entry's information. */
310 if (stat(dp->d_name, &statbuf) == -1)
311 continue;
312 /* Print out type, permissions, and number of links. */
314 printf("%10.10s", sperm (statbuf.st_mode));
315 printf("%4d", statbuf.st_nlink);
316 /* Print out owners name if it is found using getpwuid(). */
318 if ((pwd = getpwuid(statbuf.st_uid)) != NULL)
319 printf(" %-8.8s", pwd->pw_name);
320 else
321 printf(" %-8d", statbuf.st_uid);
322 /* Print out group name if it's found using getgrgid(). */
324 if ((grp = getgrgid(statbuf.st_gid)) != NULL)
325 printf(" %-8.8s", grp->gr_name);
326 else
327 printf(" %-8d", statbuf.st_gid);
328 /* Print size of file. */
330 printf(" %9jd", (intmax_t)statbuf.st_size);
331 tm = localtime(&statbuf.st_mtime);
332 /* Get localized date string. */
334 strftime(datestring, sizeof(datestring), nl_langinfo(D_T_FMT), tm);
335 printf(" %s %s\n", datestring, dp->d_name);
337 }
338 Example 3 Use fstat() to obtain file status information.
341 The following example shows how to obtain file status information for a
344 file named /home/cnd/mod1. The structure variable buffer is defined for
345 the stat structure. The /home/cnd/mod1 file is opened with read/write
346 privileges and is passed to the open file descriptor fildes.
347 #include <sys/types.h>
350 #include <sys/stat.h>
351 #include <fcntl.h>
352 struct stat buffer;
353 int status;
354 ...
355 fildes = open("/home/cnd/mod1", O_RDWR);
356 status = fstat(fildes, &buffer);
357 Example 4 Use lstat() to obtain symbolic link status information.
360 The following example shows how to obtain status information for a sym‐
363 bolic link named /modules/pass1. The structure variable buffer is
364 defined for the stat structure. If the path argument specified the
365 filename for the file pointed to by the symbolic link (/home/cnd/mod1),
366 the results of calling the function would be the same as those returned
367 by a call to the stat() function.
368 #include <sys/stat.h>
371 struct stat buffer;
372 int status;
373 ...
374 status = lstat("/modules/pass1", &buffer);
375
378 If chmod() or fchmod() is used to change the file group owner permis‐
379 sions on a file with non-trivial ACL entries, only the ACL mask is set
380 to the new permissions and the group owner permission bits in the
381 file's mode field (defined in mknod(2)) are unchanged. A non-trivial
382 ACL entry is one whose meaning cannot be represented in the file's mode
383 field alone. The new ACL mask permissions might change the effective
384 permissions for additional users and groups that have ACL entries on
385 the file.
386 The stat(), fstat(), and lstat() functions have transitional interfaces
389 for 64-bit file offsets. See lf64(5).
390
392 See attributes(5) for descriptions of the following attributes:
393 ┌─────────────────────────────┬─────────────────────────────┐
398 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
399 ├─────────────────────────────┼─────────────────────────────┤
400 │Interface Stability │Committed │
401 ├─────────────────────────────┼─────────────────────────────┤
402 │MT-Level │Async-Signal-Safe │
403 ├─────────────────────────────┼─────────────────────────────┤
404 │Standard │See below. │
405 └─────────────────────────────┴─────────────────────────────┘
406 For stat(), fstat(), and lstat(), see standards(5).
409
411 access(2), chmod(2), chown(2), creat(2), link(2), mknod(2), pipe(2),
412 read(2), time(2), unlink(2), utime(2), write(2), fattach(3C),
413 stat.h(3HEAD), attributes(5), fsattr(5), lf64(5), standards(5)
414SunOS 5.11 10 Oct 2007 stat(2)