System Calls stat(2)
NAME
stat, lstat, fstat, fstatat - get file status
SYNOPSIS
#include
#include
#include
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);DESCRIPTION
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; inthat case lstat() returns information about the link, while
stat() returns information about the file the link refer-
ences. The fstat() function obtains information about an open fileknown by the file descriptor fildes, obtained from a suc-
cessful 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 bufargument 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() func-
tion updates any pending time-related fields before writing
to the stat structure. The fstatat() function obtains file attributes similar tothe 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.SunOS 5.11 Last change: 10 Oct 2007 1
System Calls stat(2) If path is absolute, the fildes argument is unused. If thefildes argument has the special value AT_FDCWD, relative
paths are resolved from the current working directory. IfAT_SYMLINK_NOFOLLOW is set in the flag argument, the func-
tion behaves like lstat() and does not automatically follow
symbolic links. See fsattr(5). If _AT_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 The mode of the file as described for the
mknod() function. In addition to the modes described on the mknod(2) manual page, themode of a file can also be S_IFSOCK if the
file is a socket, S_IFDOOR if the file is a
door, S_IFPORT if the file is an event port,
or S_IFLNK if the file is a symbolic link.
S_IFLNK can be returned either by lstat() or
by fstat() when the AT_SYMLINK_NOFOLLOW flag
is set.SunOS 5.11 Last change: 10 Oct 2007 2
System Calls stat(2)st_ino This field uniquely identifies the file in a
given file system. The pair st_ino and
st_dev uniquely identifies regular files.
st_dev This field uniquely identifies the file system
that contains the file. Its value may be used as input to the ustat() function to determine more information about this file system. No other meaning is associated with this value.st_rdev This field should be used only by administra-
tive commands. It is valid only for block spe-
cial or character special files and only hasmeaning on the system where the file was con-
figured.st_nlink This field should be used only by administra-
tive commands.st_uid The user ID of the file's owner.
st_gid The group ID of the file's group.
st_size For regular files, this is the address of the
end of the file. For block special or charac-
ter special, this is not defined. See also pipe(2).st_atime Time when file data was last accessed. Some of
the functions that change this member are: creat(), mknod(), pipe(), utime(2), and read(2).st_mtime Time when data was last modified. Some of the
functions that change this member are: creat(), mknod(), pipe(), utime(), and write(2).st_ctime Time when file status was last changed. Some
of the functions that change this member are: chmod(2), chown(2), creat(2), link(2), mknod(2), pipe(2), rename(2), unlink(2), utime(2), and write(2).SunOS 5.11 Last change: 10 Oct 2007 3
System Calls stat(2)st_blksize A hint as to the "best" unit size for I/O
operations. This field is not defined for block special or character special files.st_blocks The total number of physical blocks of size
512 bytes actually allocated on disk. This field is not defined for block special or character special files.st_fstype A null-teminated string that uniquely identi-
fies the type of the filesystem that contains the file.RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is
returned and errno is set to indicate the error.ERRORS
The stat(), fstat(), lstat(), and fstatat() functions will
fail if: EIO An error occurred while reading from the file system. EOVERFLOW The file size in bytes or the number of blocks allocated to the file or the file serial numbercannot be represented correctly in the struc-
ture pointed to by buf.The stat(), lstat(), and fstatat() functions will fail if:
EACCES Search permission is denied for a component of the path prefix.EFAULT The buf or path argument points to an ille-
gal address. EINTR A signal was caught during the execution ofthe stat() or lstat() function.
ELOOP A loop exists in symbolic links encountered during the resolution of the path argument.SunOS 5.11 Last change: 10 Oct 2007 4
System Calls stat(2)ENAMETOOLONG The length of the path argument exceeds
{PATH_MAX}, or the length of a path com-
ponent exceeds {NAME_MAX} while
_POSIX_NO_TRUNC is in effect.
ENOENT A component of path does not name an exist-
ing file or path is an empty string. ENOLINK The path argument points to a remote machine and the link to that machine is no longer active. ENOTDIR A component of the path prefix is not a directory, or the fildes argument does not refer to a valid directory when given anon-null relative path.
The fstat() and fstatat() functions will fail if: EBADF The fildes argument is not a valid open file descriptor. The fildes argument to fstatat() canalso have the valid value of AT_FDCWD.
EFAULT The buf argument points to an illegal address. EINTR A signal was caught during the execution of the fstat() function. ENOLINK The fildes argument points to a remote machine and the link to that machine is no longer active.The stat(), fstat(), and lstat() functions may fail if:
EOVERFLOW One of the members is too large to store in the stat structure pointed to by buf.The stat() and lstat() functions may fail if:
ELOOP More than {SYMLOOP_MAX} symbolic links were
encountered during the resolution of theSunOS 5.11 Last change: 10 Oct 2007 5
System Calls stat(2) path argument.ENAMETOOLONG As a result of encountering a symbolic link
in resolution of thepath argument, the length of the substituted pathname stringsexceeds {PATH_MAX}.
The stat() and fstatat() functions may fail if: ENXIO The path argument names a character or block devicespecial file and the corresponding I/O device has been retired by the fault management framework.
EXAMPLES
Example 1 Use stat() to obtain file status information.The following example shows how to obtain file status infor-
mation for a file named /home/cnd/mod1. The structure vari-
able buffer is defined for the stat structure.#include
#include
#include
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
#include
#include
#include
#include
#include
SunOS 5.11 Last change: 10 Oct 2007 6
System Calls stat(2)#include
#include
#include
#include
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);
elseprintf(" %-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);
elseprintf(" %-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\n", datestring, dp->d_name);
} Example 3 Use fstat() to obtain file status information.The following example shows how to obtain file status infor-
mation for a file named /home/cnd/mod1. The structure vari-
able 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.SunOS 5.11 Last change: 10 Oct 2007 7
System Calls stat(2)#include
#include
#include
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 infor-
mation. 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 toby the symbolic link (/home/cnd/mod1), the results of cal-
ling the function would be the same as those returned by a call to the stat() function.#include
struct stat buffer; int status; ...status = lstat("/modules/pass1", &buffer);
USAGE
If chmod() or fchmod() is used to change the file groupowner 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).
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 10 Oct 2007 8
System Calls stat(2)____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | Async-Signal-Safe |
|_____________________________|_____________________________|
| Standard | See below. ||_____________________________|_____________________________|
For stat(), fstat(), and lstat(), see standards(5).
SEE ALSO
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)SunOS 5.11 Last change: 10 Oct 2007 9