NAME

       FAT_IOCTL_GET_ATTRIBUTES, FAT_IOCTL_SET_ATTRIBUTES - get and set file attributes in a FAT filesystem

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <linux/msdos_fs.h>  /* Definition of FAT_* and
                                       ATTR_* constants */
       #include <sys/ioctl.h>

       int ioctl(int fd, FAT_IOCTL_GET_ATTRIBUTES, uint32_t *attr);
       int ioctl(int fd, FAT_IOCTL_SET_ATTRIBUTES, uint32_t *attr);

DESCRIPTION

       Files  and  directories  in  the  FAT  filesystem  possess  an  attribute  bit mask that can be read with
       FAT_IOCTL_GET_ATTRIBUTES and written with FAT_IOCTL_SET_ATTRIBUTES.

       The fd argument contains a file descriptor for a file or directory.  It is sufficient to create the  file
       descriptor by calling open(2) with the O_RDONLY flag.

       The attr argument contains a pointer to a bit mask.  The bits of the bit mask are:

       ATTR_RO
              This bit specifies that the file or directory is read-only.

       ATTR_HIDDEN
              This bit specifies that the file or directory is hidden.

       ATTR_SYS
              This bit specifies that the file is a system file.

       ATTR_VOLUME
              This bit specifies that the file is a volume label.  This attribute is read-only.

       ATTR_DIR
              This bit specifies that this is a directory.  This attribute is read-only.

       ATTR_ARCH
              This  bit  indicates  that  this  file  or directory should be archived.  It is set when a file is
              created or modified.  It is reset by an archiving system.

       The zero value ATTR_NONE can be used to indicate that no attribute bit is set.

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned, and errno is set to indicate the error.

STANDARDS

       Linux.

HISTORY

       Linux 2.6.12.

EXAMPLES

       The following program demonstrates the usage of ioctl(2) to  manipulate  file  attributes.   The  program
       reads  and  displays  the  archive  attribute of a file.  After inverting the value of the attribute, the
       program reads and displays the attribute again.

       The following was recorded when applying the program for the file /mnt/user/foo:

           # ./toggle_fat_archive_flag /mnt/user/foo
           Archive flag is set
           Toggling archive flag
           Archive flag is not set

   Program source (toggle_fat_archive_flag.c)

       #include <fcntl.h>
       #include <linux/msdos_fs.h>
       #include <stdint.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <sys/ioctl.h>
       #include <unistd.h>

       /*
        * Read file attributes of a file on a FAT filesystem.
        * Output the state of the archive flag.
        */
       static uint32_t
       readattr(int fd)
       {
           int       ret;
           uint32_t  attr;

           ret = ioctl(fd, FAT_IOCTL_GET_ATTRIBUTES, &attr);
           if (ret == -1) {
               perror("ioctl");
               exit(EXIT_FAILURE);
           }

           if (attr & ATTR_ARCH)
               printf("Archive flag is set\n");
           else
               printf("Archive flag is not set\n");

           return attr;
       }

       int
       main(int argc, char *argv[])
       {
           int       fd;
           int       ret;
           uint32_t  attr;

           if (argc != 2) {
               printf("Usage: %s FILENAME\n", argv[0]);
               exit(EXIT_FAILURE);
           }

           fd = open(argv[1], O_RDONLY);
           if (fd == -1) {
               perror("open");
               exit(EXIT_FAILURE);
           }

           /*
            * Read and display the FAT file attributes.
            */
           attr = readattr(fd);

           /*
            * Invert archive attribute.
            */
           printf("Toggling archive flag\n");
           attr ^= ATTR_ARCH;

           /*
            * Write the changed FAT file attributes.
            */
           ret = ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &attr);
           if (ret == -1) {
               perror("ioctl");
               exit(EXIT_FAILURE);
           }

           /*
            * Read and display the FAT file attributes.
            */
           readattr(fd);

           close(fd);

           exit(EXIT_SUCCESS);
       }

SEE ALSO

       ioctl(2), ioctl_fat(2)

Linux man-pages 6.9.1                              2024-06-15                   FAT_IOCTL_SET_ATTRIBUTES(2const)