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stat(2)

stat(2)                          System Calls                          stat(2)



NAME
       stat, lstat, fstat, fstatat - get file status

SYNOPSIS
       #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);

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; 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 call to a  func‐
       tion such as open(2), creat(2), dup(2), fcntl(2), or pipe(2). 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_SYM‐
       LINK_NOFOLLOW  is  set  in the flag argument, the function behaves like
       lstat()  and  does  not  automatically  follow  symbolic   links.   See
       fsattr(7).  If _AT_TRIGGER is set in the flag argument and the vnode is
       an autofs 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 informa‐
       tion is placed concerning the file. A stat structure includes the  fol‐
       lowing members:


         mode_t         st_mode;      /* File mode (see mknod(2)) */
         ino_t          st_ino;       /* File serial 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 */
         timespec_t     st_atim;      /* Timestamp of last access */
         timespec_t     st_mtim;      /* Timestamp of last data modification */
         timespec_t     st_ctim;      /* Timestamp of last file status change */
                              /* Timestamps contain seconds and nanoseconds */
                              /* 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,  the  mode 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 sym‐
                   bolic link. S_IFLNK can be returned either by lstat() or by
                   fstatat() when the AT_SYMLINK_NOFOLLOW flag is set.

                   To  check  the  type  of  a  file, compare st_mode & S_IFMT
                   against the appropriate S_IF* macro value, or use the S_IS*
                   convenience  macros  defined in stat.h(3HEAD). To check the
                   access mode of a file, compare st_mode & S_IAMB against the
                   appropriate  file  permission  bitmask  macros  defined  in
                   stat.h(3HEAD).


       st_ino      This field uniquely identifies the file  in  a  given  file
                   system. The pair st_ino and st_dev uniquely identifies reg‐
                   ular files.


       st_dev      This field uniquely identifies the file  system  that  con‐
                   tains  the  file.  Its  value  may  be used as input to the
                   ustat(2) 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 administrative  commands.
                   It  is  valid  only  for block special or character special
                   files and only has meaning on the system where the file was
                   configured.


       st_nlink    This field should be used only by administrative 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 character special, this  is  not
                   defined. See also pipe(2).


       st_atim     Timestamp  when  file  data  was last accessed. Some of the
                   functions that change this member are: creat(2),  mknod(2),
                   pipe(2), utime(2), and read(2).


       st_mtim     Timestamp  when  data  was last modified. Some of the func‐
                   tions that change  this  member  are:  creat(2),  mknod(2),
                   pipe(2), utime(2), and write(2).


       st_ctim     Timestamp  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).


       Note -



         For compatibility with earlier versions of this structure  the  macro
         st_atime  is  defined  to access the seconds component of the st_atim
         timestamp. Similarly the macros st_mtime and st_ctime are defined  to
         provide  access  to the seconds components of the st_mtim and st_ctim
         timestamps respectively.


       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-terminated string  that  uniquely  identifies  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 number cannot be repre‐
                    sented correctly in the structure 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 illegal address.


       EINTR           A  signal was caught during the execution of the stat()
                       or lstat() function.


       ELOOP           A loop exists in symbolic links encountered during  the
                       resolution of the path argument.


       ENAMETOOLONG    The  length of the path argument exceeds {PATH_MAX}, or
                       the length of a path component exceeds {NAME_MAX} while
                       _POSIX_NO_TRUNC is in effect.


       ENOENT          A  component  of path does not name an existing 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 a non-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() can also 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 the path argument.


       ENAMETOOLONG    As  a result of encountering a symbolic link in resolu‐
                       tion of the path argument, the length  of  the  substi‐
                       tuted pathname strings exceeds {PATH_MAX}.



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

       ENXIO    The  path  argument  names a character or block device special
                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 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", mode_to_string(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\n", 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 sym‐
       bolic  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);


USAGE
       If  chmod()  or fchmod() is used to change the file group owner permis‐
       sions 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(7).

ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       tab()  box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
       TRIBUTE VALUE _ Interface  StabilityCommitted  _  MT-LevelAsync-Signal-
       Safe _ StandardSee below.



       See standards(7) for descriptions of the following standards:


       tab()  box;  cw(2.2i) |cw(3.3i) lw(2.2i) |lw(3.3i) INTERFACESAPPLICABLE
       STANDARDS _ T{
         stat()
         lstat()
         fstat()

       T}T{
         POSIX.1-1990 through 2008,
         SUS through SUSv4,
         XPG1 through XPG7

       T} _
         fstatat()
       T{
         SUSv4,
         XPG7

       T}


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(7), fsattr(7), lf64(7), standards(7)

NOTES
       Some file systems additionally provide a file  creation  timestamp,  in
       addition  to  the  timestamps  described  above.  This timestamp is not
       available through the interfaces  described  on  this  page,  but  must
       instead  be  retrieved using the getattrat(3C) function as the A_CRTIME
       system attribute.


       For testing purposes only, the behavior  of  these  interfaces  can  be
       changed  when used by a 32-bit programs on systems where the timestamps
       will not fit into the st_atime, st_mtime, or st_ctime   stat  structure
       fields. If this configuration line is present in /etc/system:

         set stat_timestamp32 = 1



       A ceiling value will be substituted for the timestamps which do not fit
       in the returned stat structure fields, and no EOVERFLOW error  will  be
       returned.  This  option allows a limited set of testing to be performed
       on systems with an advanced date/time where some  32-bit  programs  may
       still  be  in use. This option exists purely for testing purposes; some
       parts of Oracle Solaris will not behave correctly when this is used  on
       systems  with  the date advanced past 03:14:07 UTC January 19, 2038. No
       support calls will be taken on such issues.

HISTORY
       The stat(), lstat(), and fstat() functions have been  included  in  all
       Sun and Oracle releases of Solaris.


       The fstatat() function was added to Solaris in the Solaris 9 release.



Oracle Solaris 11.4               30 Apr 2020                          stat(2)
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