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Viewing: parse_foreign_file.c

#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <stdio.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/xattr.h>
#include <sys/file.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <byteswap.h>

#include <lustre/lustreapi.h>

int main(int argc, char **argv)
{
	int c, i;
	char *fname = "FILE";
	size_t len, len2;
	struct lov_foreign_md *lfm;

	while ((c = getopt(argc, argv, "f:")) != -1) {
		switch (c) {
		case 'f':
			fname = optarg;
			break;
		case 'h':
			fprintf(stderr, "Usage: %s -f <filename>\n", argv[0]);
			break;
		}
	}

	len = getxattr(fname, "lustre.lov", NULL, 0);
	if (len == -1) {
		perror("getxattr()");
		exit(1);
	}
	if (len > XATTR_SIZE_MAX || len <= 0) {
		fprintf(stderr,
			"invalid LOV EA length %zu > XATTR_SIZE_MAX (%u)\n",
			len, XATTR_SIZE_MAX);
		exit(1);
	}

	lfm = malloc(len);
	if (lfm == NULL) {
		perror("malloc()");
		exit(1);
	}

	len2 = getxattr(fname, "lustre.lov", lfm, len);
	if (len2 == -1) {
		perror("getxattr()");
		exit(1);
	}

	if (len != len2)
		fprintf(stderr,
			"trusted.lov xattr size changed, before=%zu now=%zu\n",
			len, len2);

	if (len2 < offsetof(struct lov_foreign_md, lfm_value)) {
		fprintf(stderr, "trusted.lov size=%zu too small\n", len2);
		fprintf(stderr, "printing its content in hex anyway:\n");
		for (i = 0; i < len2; i++)
			fprintf(stderr, "%02x", *((char *)lfm + i));
		exit(1);
	}


	if (lfm->lfm_magic != LOV_USER_MAGIC_FOREIGN) {
		if (lfm->lfm_magic == bswap_32(LOV_USER_MAGIC_FOREIGN))
			fprintf(stderr, "magic is swapped\n");
		else
			fprintf(stderr, "wrong magic=(0x%x)\n", lfm->lfm_magic);
	}

	if (lfm->lfm_length != len2 - offsetof(typeof(*lfm), lfm_value)) {
		if (bswap_32(lfm->lfm_length) == len2 - offsetof(typeof(*lfm),
		    lfm_value))
			fprintf(stderr, "length is swapped\n");
		else
			fprintf(stderr,
				"wrong internal length=%u vs xattr size=%zu\n",
				lfm->lfm_length, len2);
	}

	if (lfm->lfm_magic == bswap_32(LOV_USER_MAGIC_FOREIGN)) {
		lfm->lfm_magic = bswap_32(lfm->lfm_magic);
		lfm->lfm_length = bswap_32(lfm->lfm_length);
		lfm->lfm_type = bswap_32(lfm->lfm_type);
		lfm->lfm_flags = bswap_32(lfm->lfm_flags);
	}

	fprintf(stdout, "lov_xattr_size: %zu\n", len2);
	fprintf(stdout, "lov_foreign_magic: 0x%08X\n", lfm->lfm_magic);
	fprintf(stdout, "lov_foreign_size: %u\n", lfm->lfm_length);
	fprintf(stdout, "lov_foreign_type: %u\n", lfm->lfm_type);
	fprintf(stdout, "lov_foreign_flags: 0x%08X\n", lfm->lfm_flags);
	fprintf(stdout, "lov_foreign_value: 0x");
	for (i = 0; i < len2 - offsetof(typeof(*lfm), lfm_value); i++)
		fprintf(stdout, "%02x", lfm->lfm_value[i]);

	fprintf(stdout, "\n");

	return 0;
}