githubmirror/efivar

src/linux-emmc.c
110 строк3 KB
Hans de Goede
Fix /sys/block sysfs parsing for eMMC-s
22 апр 2020, 21:06
22 апр 2020, 21:06f0d3ed1
// SPDX-License-Identifier: LGPL-2.1-or-later
/*
 * libefiboot - library for the manipulation of EFI boot variables
 * Copyright 2012-2019 Red Hat, Inc.
 */

#include "fix_coverity.h"

#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdint.h>
#include <sys/param.h>
#include <unistd.h>

#include "efiboot.h"

/*
 * support for emmc devices
 *
 * /sys/dev/block/$major:$minor looks like:
 * 179:0 -> ../../devices/pci0000:00/0000:00:1c.0/mmc_host/mmc0/mmc0:0001/block/mmcblk0
 * 179:1 -> ../../devices/pci0000:00/0000:00:1c.0/mmc_host/mmc0/mmc0:0001/block/mmcblk0/mmcblk0p1
 *
 * /sys/dev/block/179:0/device looks like:
 * device -> ../../../mmc0:0001
 *
 * /sys/dev/block/179:1/partition looks like:
 * $ cat partition
 * 1
 *
 */

static ssize_t
parse_emmc(struct device *dev, const char *path, const char *root UNUSED)
{
	const char * current = path;
	int rc;
	int32_t tosser0, tosser1, tosser2, tosser3, slot_id, partition;
	int pos0 = -1, pos1 = -1, pos2 = -1;

	debug("entry");

	debug("searching for mmc_host/mmc0/mmc0:0001/block/mmcblk0 or mmc_host/mmc0/mmc0:0001/block/mmcblk0/mmcblk0p1");
	rc = sscanf(current, "%nmmc_host/mmc%d/mmc%d:%d/block/mmcblk%d%n/mmcblk%dp%d%n",
	            &pos0, &tosser0, &tosser1, &tosser2, &slot_id,
	            &pos1, &tosser3, &partition, &pos2);
	debug("current:\"%s\" rc:%d pos0:%d pos1:%d pos2:%d\n", current, rc, pos0, pos1, pos2);
	dbgmk("         ", pos0, MAX(pos1,pos2));
	/*
	 * If it isn't of that form, it's not one of our emmc devices.
	 */
	if (rc != 4 && rc != 6)
	        return 0;

	dev->emmc_info.slot_id = slot_id;
	dev->interface_type = emmc;

	if (rc == 6 && dev->part == -1)
                dev->part = partition;

	current += pos1;

	debug("current:'%s' sz:%zd", current, current - path);
	return current - path;
}

static ssize_t
dp_create_emmc(struct device *dev,
	       uint8_t *buf,  ssize_t size, ssize_t off)
{
	ssize_t sz;

	debug("entry");

	sz = efidp_make_emmc(buf + off, size ? size - off : 0,
	                     dev->emmc_info.slot_id);
	return sz;
}

static char *
make_part_name(struct device *dev)
{
	char *ret = NULL;
	ssize_t rc;

	if (dev->part < 1)
	        return NULL;

	rc = asprintf(&ret, "%sp%d", dev->disk_name, dev->part);
	if (rc < 0) {
	        efi_error("could not allocate memory");
	        return NULL;
	}

	return ret;
}

static enum interface_type emmc_iftypes[] = { emmc, unknown };

struct dev_probe HIDDEN emmc_parser = {
	.name = "emmc",
	.iftypes = emmc_iftypes,
	.flags = DEV_PROVIDES_HD,
	.parse = parse_emmc,
	.create = dp_create_emmc,
	.make_part_name = make_part_name,
};

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