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Copyright 1989 AT&T.
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stat, lstat, fstat, fstatat - get file status

#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

int stat(const char *restrict path, struct stat *restrict buf);

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

int fstat(int fildes, struct stat *buf);

int fstatat(int fildes, const char *path, struct stat *buf,
 int flag);

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.

The lstat() function obtains file attributes similar to stat(), except when the named file is a symbolic link; in that case lstat() returns information about the link, while stat() returns information about the file the link references.

The fstat() function obtains information about an open file known by the file descriptor fildes, obtained from a successful open(2), creat(2), dup(2), fcntl(2), or pipe(2) function. If fildes references a shared memory object, the system updates in the stat structure pointed to by the buf argument only the st_uid, st_gid, st_size, and st_mode fields, and only the S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file permission bits need be valid. The system can update other fields and flags. The fstat() function updates any pending time-related fields before writing to the stat structure.

The fstatat() function obtains file attributes similar to the stat(), lstat(), and fstat() functions. If the path argument is a relative path, it is resolved relative to the fildes argument rather than the current working directory. If path is absolute, the fildes argument is unused. If the fildes argument has the special value AT_FDCWD, relative paths are resolved from the current working directory. If AT_SYMLINK_NOFOLLOW is set in the flag argument, the function behaves like lstat() and does not automatically follow symbolic links. See fsattr(5). If _ATTR_TRIGGER is set in the flag argument and the vnode is a trigger mount point, the mount is performed and the function returns the attributes of the root of the mounted filesystem.

The buf argument is a pointer to a stat structure into which information is placed concerning the file. A stat structure includes the following members:

mode_t st_mode; /* File mode (see mknod(2)) */
ino_t st_ino; /* Inode number */
dev_t st_dev; /* ID of device containing */
 /* a directory entry for this file */
dev_t st_rdev; /* ID of device */
 /* This entry is defined only for */
 /* char special or block special files */
nlink_t st_nlink; /* Number of links */
uid_t st_uid; /* User ID of the file's owner */
gid_t st_gid; /* Group ID of the file's group */
off_t st_size; /* File size in bytes */
time_t st_atime; /* Time of last access */
time_t st_mtime; /* Time of last data modification */
time_t st_ctime; /* Time of last file status change */
 /* Times measured in seconds since */
 /* 00:00:00 UTC, Jan. 1, 1970 */
long st_blksize; /* Preferred I/O block size */
blkcnt_t st_blocks; /* Number of 512 byte blocks allocated*/
char st_fstype[_ST_FSTYPSZ];
 /* Null-terminated type of filesystem */

Descriptions of structure members are as follows:

st_mode

st_ino

st_dev

st_rdev

st_nlink

st_uid

st_gid

st_size

st_atime

st_mtime

st_ctime

st_blksize

st_blocks

st_fstype

Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

The stat(), fstat(), lstat(), and fstatat() functions will fail if:

EIO

EOVERFLOW

The stat(), lstat(), and fstatat() functions will fail if:

EACCES

EFAULT

EINTR

ELOOP

ENAMETOOLONG

ENOENT

ENOLINK

ENOTDIR

The fstat() and fstatat() functions will fail if:

EBADF

EFAULT

EINTR

ENOLINK

The stat(), fstat(), and lstat() functions may fail if:

EOVERFLOW

The stat() and lstat() functions may fail if:

ELOOP

ENAMETOOLONG

The stat() and fstatat() functions may fail if:

ENXIO

Example 1 Use stat() to obtain file status information.

The following example shows how to obtain file status information for a file named /home/cnd/mod1. The structure variable buffer is defined for the stat structure.

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
struct stat buffer;
int status;
...
status = stat("/home/cnd/mod1", &buffer);

Example 2 Use stat() to get directory information.

The following example fragment gets status information for each entry in a directory. The call to the stat() function stores file information in the stat structure pointed to by statbuf. The lines that follow the stat() call format the fields in the stat structure for presentation to the user of the program.

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <locale.h>
#include <langinfo.h>
#include <stdio.h>
#include <stdint.h>
struct dirent *dp;
struct stat statbuf;
struct passwd *pwd;
struct group *grp;
struct tm *tm;
char datestring[256];
...
/* Loop through directory entries */
while ((dp = readdir(dir)) != NULL) {
 /* Get entry's information. */
 if (stat(dp->d_name, &statbuf) == -1)
 continue;
 
 /* Print out type, permissions, and number of links. */
 printf("%10.10s", sperm (statbuf.st_mode));
 printf("%4d", statbuf.st_nlink);
 
 /* Print out owners name if it is found using getpwuid(). */
 if ((pwd = getpwuid(statbuf.st_uid)) != NULL)
 printf(" %-8.8s", pwd->pw_name);
 else
 printf(" %-8d", statbuf.st_uid);
 
 /* Print out group name if it's found using getgrgid(). */
 if ((grp = getgrgid(statbuf.st_gid)) != NULL)
 printf(" %-8.8s", grp->gr_name);
 else
 printf(" %-8d", statbuf.st_gid);

 /* Print size of file. */
 printf(" %9jd", (intmax_t)statbuf.st_size);
 tm = localtime(&statbuf.st_mtime);
 
 /* Get localized date string. */
 strftime(datestring, sizeof(datestring), nl_langinfo(D_T_FMT), tm);
 
 printf(" %s %s\en", datestring, dp->d_name);
 }

Example 3 Use fstat() to obtain file status information.

The following example shows how to obtain file status information for a file named /home/cnd/mod1. The structure variable buffer is defined for the stat structure. The /home/cnd/mod1 file is opened with read/write privileges and is passed to the open file descriptor fildes.

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
struct stat buffer;
int status;
...
fildes = open("/home/cnd/mod1", O_RDWR);
status = fstat(fildes, &buffer);

Example 4 Use lstat() to obtain symbolic link status information.

The following example shows how to obtain status information for a symbolic link named /modules/pass1. The structure variable buffer is defined for the stat structure. If the path argument specified the filename for the file pointed to by the symbolic link (/home/cnd/mod1), the results of calling the function would be the same as those returned by a call to the stat() function.

#include <sys/stat.h>
struct stat buffer;
int status;
...
status = lstat("/modules/pass1", &buffer);

If chmod() or fchmod() is used to change the file group owner permissions on a file with non-trivial ACL entries, only the ACL mask is set to the new permissions and the group owner permission bits in the file's mode field (defined in mknod(2)) are unchanged. A non-trivial ACL entry is one whose meaning cannot be represented in the file's mode field alone. The new ACL mask permissions might change the effective permissions for additional users and groups that have ACL entries on the file.

The stat(), fstat(), and lstat() functions have transitional interfaces for 64-bit file offsets. See lf64(5).

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Committed
MT-Level	Async-Signal-Safe
Standard	See below.

For stat(), fstat(), and lstat(), see standards(5).

access(2), chmod(2), chown(2), creat(2), link(2), mknod(2), pipe(2), read(2), time(2), unlink(2), utime(2), write(2), fattach(3C), stat.h(3HEAD), attributes(5), fsattr(5), lf64(5), standards(5)