GETINODE(3)            FreeBSD Library Functions Manual            GETINODE(3)

NAME
     getinode, putinode - fetch and store inodes on a UFS file system

LIBRARY
     UFS File System Access Library (libufs, -lufs)

SYNOPSIS
     #include <ufs/ufs/dinode.h>
     #include <ufs/ffs/fs.h>
     #include <libufs.h>

     int
     getinode(struct uufsd *disk, union dinodep *dp, ino_t inumber);

     int
     putinode(struct uufsd *disk);

DESCRIPTION
     The getinode() and putinode() functions provide an inode fetch and store
     API for libufs(3) consumers.  They operate on a userland UFS disk
     structure.  The getinode() function fetches the specified inode from the
     filesystem.  The putinode() function stores the most recently fetched
     inode to the filesystem.

     The dinodep union is defined as:

           union dinodep {
                   struct ufs1_dinode *dp1;
                   struct ufs2_dinode *dp2;
           };

     Sample code to clear write permissions for inode number inumber stored on
     the filesystem described by diskp.

           #include <sys/stat.h>
           #include <err.h>

           #include <ufs/ufs/dinode.h>
           #include <ufs/ffs/fs.h>
           #include <libufs.h>

           void
           clearwrite(struct uufsd *diskp, ino_t inumber)
           {
                   union dinodep dp;

                   if (getinode(diskp, &dp, inumber) == -1)
                           err(1, "getinode: %s", diskp->d_error);
                   switch (diskp->d_ufs) {
                   case 1: /* UFS 1 filesystem */
                           dp.dp1->di_mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
                           break;
                   case 2: /* UFS 2 filesystem */
                           dp.dp2->di_mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
                           break;
                   default:
                           errx(1, "unknown filesystem type");
                   }
                   if (putinode(diskp) == -1)
                           err(1, "putinode: %s", diskp->d_error);
           }

RETURN VALUES
     The getinode() and putinode() functions return 0 on success, or -1 in
     case of any error.  A string describing the error is stored in
     diskp->d_error.  The global errno often provides additional information.

ERRORS
     The function getinode() may fail and set errno for any of the errors
     specified for the library function pread(2).  It can also fail if the
     inode number is out of the range of inodes in the filesystem.

     The function putinode() may fail and set errno for any of the errors
     specified for the library functions ufs_disk_write(3) or pwrite(2).

     Additionally both functions may follow the libufs(3) error methodologies
     in case of a device error.

SEE ALSO
     pread(2), pwrite(2), libufs(3), ufs_disk_write(3)

HISTORY
     These functions first appeared as part of libufs(3) in FreeBSD 13.0.

AUTHORS
     Marshall Kirk McKusick <mckusick@FreeBSD.org>

FreeBSD 13.1-RELEASE-p6        September 2, 2020       FreeBSD 13.1-RELEASE-p6