libfrog/linux.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */

#include <mntent.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/sysinfo.h>

#include "platform_defs.h"
#include "xfs.h"
#include "init.h"
#include "libfrog/platform.h"

extern char *progname;
static int max_block_alignment;

#ifndef BLKGETSIZE64
# define BLKGETSIZE64	_IOR(0x12,114,size_t)
#endif
#ifndef BLKBSZSET
# define BLKBSZSET	_IOW(0x12,113,size_t)
#endif
#ifndef BLKSSZGET
# define BLKSSZGET	_IO(0x12,104)
#endif

#ifndef RAMDISK_MAJOR
#define RAMDISK_MAJOR	1	/* ramdisk major number */
#endif

#define PROC_MOUNTED	"/proc/mounts"

/*
 * Check if the filesystem is mounted.  Be verbose if asked, and
 * optionally restrict check to /writable/ mounts (i.e. RO is OK)
 */
#define	CHECK_MOUNT_VERBOSE	0x1
#define	CHECK_MOUNT_WRITABLE	0x2

static int
platform_check_mount(char *name, char *block, struct stat *s, int flags)
{
	FILE		*f;
	struct stat	st, mst;
	struct mntent	*mnt;
	char		mounts[MAXPATHLEN];

	if (!s) {
		/* If either fails we are not mounted */
		if (stat(block, &st) < 0)
			return 0;
		if ((st.st_mode & S_IFMT) != S_IFBLK)
			return 0;
		s = &st;
	}

	strcpy(mounts, (!access(PROC_MOUNTED, R_OK)) ? PROC_MOUNTED : MOUNTED);
	if ((f = setmntent(mounts, "r")) == NULL) {
		/* Unexpected failure, warn unconditionally */
		fprintf(stderr,
		    _("%s: %s possibly contains a mounted filesystem\n"),
		    progname, name);
		return 1;
	}
	/*
	 * This whole business is to work out if our block device is mounted
	 * after we lost ustat(2), see:
	 *      4e7a824 libxfs/linux.c: Replace use of ustat by stat
	 * We don't really want to stat every single mounted directory,
	 * as that may include tmpfs, cgroups, procfs or - worst - hung nfs
	 * servers.  So first, a simple check: does the "dev" start with "/" ?
	 */
	while ((mnt = getmntent(f)) != NULL) {
		if (!strcmp(mnt->mnt_type, "autofs"))
			continue;
		if (mnt->mnt_fsname[0] != '/')
			continue;
		if (stat(mnt->mnt_dir, &mst) < 0)
			continue;
		if (mst.st_dev != s->st_rdev)
			continue;
		/* Found our device, is RO OK? */
		if ((flags & CHECK_MOUNT_WRITABLE) && hasmntopt(mnt, MNTOPT_RO))
			continue;
		else
			break;
	}
	endmntent(f);

	/* No mounts contained the condition we were looking for */
	if (mnt == NULL)
		return 0;

	if (flags & CHECK_MOUNT_VERBOSE) {
		if (flags & CHECK_MOUNT_WRITABLE) {
			fprintf(stderr,
_("%s: %s contains a mounted and writable filesystem\n"),
				progname, name);
		} else {
			fprintf(stderr,
_("%s: %s contains a mounted filesystem\n"),
				progname, name);
		}
	}
	return 1;
}

int
platform_check_ismounted(char *name, char *block, struct stat *s, int verbose)
{
	int flags;

	flags = verbose ? CHECK_MOUNT_VERBOSE : 0;
	return platform_check_mount(name, block, s, flags);
}

int
platform_check_iswritable(char *name, char *block, struct stat *s)
{
	int flags;

	/* Writable checks are always verbose */
	flags = CHECK_MOUNT_WRITABLE | CHECK_MOUNT_VERBOSE;
	return platform_check_mount(name, block, s, flags);
}

void
platform_set_blocksize(int fd, char *path, dev_t device, int blocksize,
		bool fatal)
{
	int error;

	if (major(device) == RAMDISK_MAJOR)
		return;
	error = ioctl(fd, BLKBSZSET, &blocksize);
	if (error < 0) {
		fprintf(stderr, _("%s: %s - cannot set blocksize "
				"%d on block device %s: %s\n"),
			progname, fatal ? "error": "warning",
			blocksize, path, strerror(errno));
		if (fatal)
			exit(1);
	}
}

/*
 * Flush dirty pagecache and disk write cache to stable media.  Returns 0 for
 * success or -1 (with errno set) for failure.
 */
int
platform_flush_device(
	int		fd,
	dev_t		device)
{
	struct stat	st;
	int		ret;

	if (major(device) == RAMDISK_MAJOR)
		return 0;

	ret = fsync(fd);
	if (ret)
		return ret;

	ret = fstat(fd, &st);
	if (ret)
		return ret;

	if (S_ISBLK(st.st_mode))
		return ioctl(fd, BLKFLSBUF, 0);

	return 0;
}

void
platform_findsizes(char *path, int fd, long long *sz, int *bsz)
{
	struct stat	st;
	uint64_t	size;
	int		error;

	if (fstat(fd, &st) < 0) {
		fprintf(stderr, _("%s: "
			"cannot stat the device file \"%s\": %s\n"),
			progname, path, strerror(errno));
		exit(1);
	}

	if ((st.st_mode & S_IFMT) == S_IFREG) {
		struct dioattr	da;

		*sz = (long long)(st.st_size >> 9);

		if (ioctl(fd, XFS_IOC_DIOINFO, &da) < 0) {
			/*
			 * fall back to BBSIZE; mkfs might fail if there's a
			 * size mismatch between the image & the host fs...
			 */
			*bsz = BBSIZE;
		} else
			*bsz = da.d_miniosz;

		if (*bsz > max_block_alignment)
			max_block_alignment = *bsz;
		return;
	}

	error = ioctl(fd, BLKGETSIZE64, &size);
	if (error >= 0) {
		/* BLKGETSIZE64 returns size in bytes not 512-byte blocks */
		*sz = (long long)(size >> 9);
	} else {
		/* If BLKGETSIZE64 fails, try BLKGETSIZE */
		unsigned long tmpsize;

		error = ioctl(fd, BLKGETSIZE, &tmpsize);
		if (error < 0) {
			fprintf(stderr, _("%s: can't determine device size\n"),
				progname);
			exit(1);
		}
		*sz = (long long)tmpsize;
	}

	if (ioctl(fd, BLKSSZGET, bsz) < 0) {
		fprintf(stderr, _("%s: warning - cannot get sector size "
				"from block device %s: %s\n"),
			progname, path, strerror(errno));
		*bsz = BBSIZE;
	}
	if (*bsz > max_block_alignment)
		max_block_alignment = *bsz;
}

int
platform_direct_blockdev(void)
{
	return 1;
}

int
platform_align_blockdev(void)
{
	if (!max_block_alignment)
		return getpagesize();
	return max_block_alignment;
}

/* How many CPUs are online? */
int
platform_nproc(void)
{
	long nproc = sysconf(_SC_NPROCESSORS_ONLN);

	if (nproc < 1)
		return 1;
	if (nproc >= INT_MAX)
		return INT_MAX;
	return nproc;
}

unsigned long
platform_physmem(void)
{
	struct sysinfo  si;

	if (sysinfo(&si) < 0) {
		fprintf(stderr, _("%s: can't determine memory size\n"),
			progname);
		exit(1);
	}
	return (si.totalram >> 10) * si.mem_unit;	/* kilobytes */
}