130 lines
2.7 KiB
Groff
130 lines
2.7 KiB
Groff
.\" Author: Marshall Kirk McKusick <mckusick@freebsd.org>
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.\" Date: January 19, 2018
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.\" Description:
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.\" Manual page for libufs functions:
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.\" getinode(3)
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.\" putinode(3)
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.\"
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.\" This file is in the public domain.
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.\"
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.Dd September 2, 2020
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.Dt GETINODE 3
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.Os
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.Sh NAME
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.Nm getinode , putinode
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.Nd fetch and store inodes on a UFS file system
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.Sh LIBRARY
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.Lb libufs
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.Sh SYNOPSIS
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.In ufs/ufs/dinode.h
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.In ufs/ffs/fs.h
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.In libufs.h
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.Ft int
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.Fn getinode "struct uufsd *disk" "union dinodep *dp" "ino_t inumber"
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.Ft int
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.Fn putinode "struct uufsd *disk"
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.Sh DESCRIPTION
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The
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.Fn getinode
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and
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.Fn putinode
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functions provide an inode fetch and store API for
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.Xr libufs 3
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consumers.
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They operate on a userland UFS disk structure.
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The
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.Fn getinode
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function fetches the specified inode from the filesystem.
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The
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.Fn putinode
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function stores the most recently fetched inode to the filesystem.
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.Pp
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The
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.Va dinodep
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union is defined as:
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.Bd -literal -offset indent
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union dinodep {
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struct ufs1_dinode *dp1;
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struct ufs2_dinode *dp2;
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};
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.Ed
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.Pp
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Sample code to clear write permissions for inode number
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.Fa inumber
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stored on the filesystem described by
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.Fa diskp .
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.Bd -literal -offset indent
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#include <sys/stat.h>
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#include <err.h>
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#include <ufs/ufs/dinode.h>
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#include <ufs/ffs/fs.h>
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#include <libufs.h>
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void
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clearwrite(struct uufsd *diskp, ino_t inumber)
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{
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union dinodep dp;
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if (getinode(diskp, &dp, inumber) == -1)
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err(1, "getinode: %s", diskp->d_error);
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switch (diskp->d_ufs) {
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case 1: /* UFS 1 filesystem */
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dp.dp1->di_mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
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break;
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case 2: /* UFS 2 filesystem */
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dp.dp2->di_mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
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break;
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default:
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errx(1, "unknown filesystem type");
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}
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if (putinode(diskp) == -1)
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err(1, "putinode: %s", diskp->d_error);
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}
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.Ed
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.Sh RETURN VALUES
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The
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.Fn getinode
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and
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.Fn putinode
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functions return 0 on success, or \-1 in case of any error.
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A string describing the error is stored in
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.Fa diskp->d_error .
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The global
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.Fa errno
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often provides additional information.
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.Sh ERRORS
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The function
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.Fn getinode
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may fail and set
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.Va errno
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for any of the errors specified for the library function
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.Xr pread 2 .
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It can also fail if the inode number is out of the range of inodes
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in the filesystem.
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.Pp
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The function
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.Fn putinode
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may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr ufs_disk_write 3
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or
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.Xr pwrite 2 .
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.Pp
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Additionally both functions may follow the
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.Xr libufs 3
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error methodologies in case of a device error.
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.Sh SEE ALSO
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.Xr pread 2 ,
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.Xr pwrite 2 ,
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.Xr libufs 3 ,
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.Xr ufs_disk_write 3
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.Sh HISTORY
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These functions first appeared as part of
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.Xr libufs 3
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in
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.Fx 13.0 .
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.Sh AUTHORS
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.An Marshall Kirk McKusick Aq Mt mckusick@FreeBSD.org
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