pmem2_utils_linux.c

// SPDX-License-Identifier: BSD-3-Clause
/* Copyright 2014-2023, Intel Corporation */

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>

#include "libpmem2.h"
#include "out.h"
#include "pmem2_utils.h"
#include "region_namespace.h"
#include "source.h"
#include "alloc.h"

/*
 * pmem2_get_type_from_stat -- determine type of file based on output of stat
 * syscall
 */
int
pmem2_get_type_from_stat(const os_stat_t *st, enum pmem2_file_type *type)
{
	if (S_ISREG(st->st_mode)) {
		*type = PMEM2_FTYPE_REG;
		return 0;
	}

	if (S_ISDIR(st->st_mode)) {
		*type = PMEM2_FTYPE_DIR;
		return 0;
	}

	if (!S_ISCHR(st->st_mode)) {
		ERR("file type 0%o not supported", st->st_mode & S_IFMT);
		return PMEM2_E_INVALID_FILE_TYPE;
	}

	int ret = 0;
	char *spath = NULL;
	char *npath = NULL;

	spath = Malloc(PATH_MAX);
	if (spath == NULL) {
		errno = ENOMEM;
		ERR("!Malloc");
		return PMEM2_E_ERRNO;
	}

	ret = util_snprintf(spath, PATH_MAX,
			"/sys/dev/char/%u:%u/subsystem",
			os_major(st->st_rdev), os_minor(st->st_rdev));

	if (ret < 0) {
		/* impossible */
		ERR("!snprintf");
		ASSERTinfo(0, "snprintf failed");
		ret = PMEM2_E_ERRNO;
		goto end;
	}

	LOG(4, "device subsystem path \"%s\"", spath);

	npath = Malloc(PATH_MAX);
	if (npath == NULL) {
		errno = ENOMEM;
		ERR("!Malloc");
		ret = PMEM2_E_ERRNO;
		goto end;
	}

	char *rpath = realpath(spath, npath);
	if (rpath == NULL) {
		ERR("!realpath \"%s\"", spath);
		ret = PMEM2_E_ERRNO;
		goto end;
	}

	char *basename = strrchr(rpath, '/');
	if (!basename || strcmp("dax", basename + 1) != 0) {
		LOG(3, "%s path does not match device dax prefix path", rpath);
		ret = PMEM2_E_INVALID_FILE_TYPE;
		goto end;
	}

	*type = PMEM2_FTYPE_DEVDAX;

end:
	if (spath)
		Free(spath);
	if (npath)
		Free(npath);

	return ret;
}