getinode3

Usage

Library

library “libufs”

Overview

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.