Systemd/src/udev/ata_id/ata_id.c

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * ata_id - reads product/serial number from ATA drives
 *
 * Copyright © 2009-2010 David Zeuthen <zeuthen@gmail.com>
 */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <linux/bsg.h>
#include <linux/hdreg.h>
#include <scsi/scsi.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/sg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "fd-util.h"
#include "libudev-util.h"
#include "log.h"
#include "memory-util.h"
#include "udev-util.h"

#define COMMAND_TIMEOUT_MSEC (30 * 1000)

static int disk_scsi_inquiry_command(
                int fd,
                void *buf,
                size_t buf_len) {

        uint8_t cdb[6] = {
                /* INQUIRY, see SPC-4 section 6.4 */
                [0] = 0x12,                /* OPERATION CODE: INQUIRY */
                [3] = (buf_len >> 8),      /* ALLOCATION LENGTH */
                [4] = (buf_len & 0xff),
        };
        uint8_t sense[32] = {};
        struct sg_io_v4 io_v4 = {
                .guard = 'Q',
                .protocol = BSG_PROTOCOL_SCSI,
                .subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD,
                .request_len = sizeof(cdb),
                .request = (uintptr_t) cdb,
                .max_response_len = sizeof(sense),
                .response = (uintptr_t) sense,
                .din_xfer_len = buf_len,
                .din_xferp = (uintptr_t) buf,
                .timeout = COMMAND_TIMEOUT_MSEC,
        };
        int ret;

        ret = ioctl(fd, SG_IO, &io_v4);
        if (ret != 0) {
                /* could be that the driver doesn't do version 4, try version 3 */
                if (errno == EINVAL) {
                        struct sg_io_hdr io_hdr = {
                                .interface_id = 'S',
                                .cmdp = (unsigned char*) cdb,
                                .cmd_len = sizeof (cdb),
                                .dxferp = buf,
                                .dxfer_len = buf_len,
                                .sbp = sense,
                                .mx_sb_len = sizeof(sense),
                                .dxfer_direction = SG_DXFER_FROM_DEV,
                                .timeout = COMMAND_TIMEOUT_MSEC,
                        };

                        ret = ioctl(fd, SG_IO, &io_hdr);
                        if (ret != 0)
                                return ret;

                        /* even if the ioctl succeeds, we need to check the return value */
                        if (!(io_hdr.status == 0 &&
                              io_hdr.host_status == 0 &&
                              io_hdr.driver_status == 0)) {
                                errno = EIO;
                                return -1;
                        }
                } else
                        return ret;
        }

        /* even if the ioctl succeeds, we need to check the return value */
        if (!(io_v4.device_status == 0 &&
              io_v4.transport_status == 0 &&
              io_v4.driver_status == 0)) {
                errno = EIO;
                return -1;
        }

        return 0;
}

static int disk_identify_command(
                int fd,
                void *buf,
                size_t buf_len) {

        uint8_t cdb[12] = {
                /*
                 * ATA Pass-Through 12 byte command, as described in
                 *
                 *  T10 04-262r8 ATA Command Pass-Through
                 *
                 * from http://www.t10.org/ftp/t10/document.04/04-262r8.pdf
                 */
                [0] = 0xa1,     /* OPERATION CODE: 12 byte pass through */
                [1] = 4 << 1,   /* PROTOCOL: PIO Data-in */
                [2] = 0x2e,     /* OFF_LINE=0, CK_COND=1, T_DIR=1, BYT_BLOK=1, T_LENGTH=2 */
                [3] = 0,        /* FEATURES */
                [4] = 1,        /* SECTORS */
                [5] = 0,        /* LBA LOW */
                [6] = 0,        /* LBA MID */
                [7] = 0,        /* LBA HIGH */
                [8] = 0 & 0x4F, /* SELECT */
                [9] = 0xEC,     /* Command: ATA IDENTIFY DEVICE */
        };
        uint8_t sense[32] = {};
        uint8_t *desc = sense + 8;
        struct sg_io_v4 io_v4 = {
                .guard = 'Q',
                .protocol = BSG_PROTOCOL_SCSI,
                .subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD,
                .request_len = sizeof(cdb),
                .request = (uintptr_t) cdb,
                .max_response_len = sizeof(sense),
                .response = (uintptr_t) sense,
                .din_xfer_len = buf_len,
                .din_xferp = (uintptr_t) buf,
                .timeout = COMMAND_TIMEOUT_MSEC,
        };
        int ret;

        ret = ioctl(fd, SG_IO, &io_v4);
        if (ret != 0) {
                /* could be that the driver doesn't do version 4, try version 3 */
                if (errno == EINVAL) {
                        struct sg_io_hdr io_hdr = {
                                .interface_id = 'S',
                                .cmdp = (unsigned char*) cdb,
                                .cmd_len = sizeof (cdb),
                                .dxferp = buf,
                                .dxfer_len = buf_len,
                                .sbp = sense,
                                .mx_sb_len = sizeof (sense),
                                .dxfer_direction = SG_DXFER_FROM_DEV,
                                .timeout = COMMAND_TIMEOUT_MSEC,
                        };

                        ret = ioctl(fd, SG_IO, &io_hdr);
                        if (ret != 0)
                                return ret;
                } else
                        return ret;
        }

        if (!(sense[0] == 0x72 && desc[0] == 0x9 && desc[1] == 0x0c) &&
                !(sense[0] == 0x70 && sense[12] == 0x00 && sense[13] == 0x1d)) {
                errno = EIO;
                return -1;
        }

        return 0;
}

static int disk_identify_packet_device_command(
                int fd,
                void *buf,
                size_t buf_len) {

        uint8_t cdb[16] = {
                /*
                 * ATA Pass-Through 16 byte command, as described in
                 *
                 *  T10 04-262r8 ATA Command Pass-Through
                 *
                 * from http://www.t10.org/ftp/t10/document.04/04-262r8.pdf
                 */
                [0] = 0x85,   /* OPERATION CODE: 16 byte pass through */
                [1] = 4 << 1, /* PROTOCOL: PIO Data-in */
                [2] = 0x2e,   /* OFF_LINE=0, CK_COND=1, T_DIR=1, BYT_BLOK=1, T_LENGTH=2 */
                [3] = 0,      /* FEATURES */
                [4] = 0,      /* FEATURES */
                [5] = 0,      /* SECTORS */
                [6] = 1,      /* SECTORS */
                [7] = 0,      /* LBA LOW */
                [8] = 0,      /* LBA LOW */
                [9] = 0,      /* LBA MID */
                [10] = 0,     /* LBA MID */
                [11] = 0,     /* LBA HIGH */
                [12] = 0,     /* LBA HIGH */
                [13] = 0,     /* DEVICE */
                [14] = 0xA1,  /* Command: ATA IDENTIFY PACKET DEVICE */
                [15] = 0,     /* CONTROL */
        };
        uint8_t sense[32] = {};
        uint8_t *desc = sense + 8;
        struct sg_io_v4 io_v4 = {
                .guard = 'Q',
                .protocol = BSG_PROTOCOL_SCSI,
                .subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD,
                .request_len = sizeof (cdb),
                .request = (uintptr_t) cdb,
                .max_response_len = sizeof (sense),
                .response = (uintptr_t) sense,
                .din_xfer_len = buf_len,
                .din_xferp = (uintptr_t) buf,
                .timeout = COMMAND_TIMEOUT_MSEC,
        };
        int ret;

        ret = ioctl(fd, SG_IO, &io_v4);
        if (ret != 0) {
                /* could be that the driver doesn't do version 4, try version 3 */
                if (errno == EINVAL) {
                        struct sg_io_hdr io_hdr = {
                                .interface_id = 'S',
                                .cmdp = (unsigned char*) cdb,
                                .cmd_len = sizeof (cdb),
                                .dxferp = buf,
                                .dxfer_len = buf_len,
                                .sbp = sense,
                                .mx_sb_len = sizeof (sense),
                                .dxfer_direction = SG_DXFER_FROM_DEV,
                                .timeout = COMMAND_TIMEOUT_MSEC,
                        };

                        ret = ioctl(fd, SG_IO, &io_hdr);
                        if (ret != 0)
                                return ret;
                } else
                        return ret;
        }

        if (!(sense[0] == 0x72 && desc[0] == 0x9 && desc[1] == 0x0c)) {
                errno = EIO;
                return -1;
        }

        return 0;
}

/**
 * disk_identify_get_string:
 * @identify: A block of IDENTIFY data
 * @offset_words: Offset of the string to get, in words.
 * @dest: Destination buffer for the string.
 * @dest_len: Length of destination buffer, in bytes.
 *
 * Copies the ATA string from @identify located at @offset_words into @dest.
 */
static void disk_identify_get_string(
                uint8_t identify[512],
                unsigned offset_words,
                char *dest,
                size_t dest_len) {

        unsigned c1;
        unsigned c2;

        while (dest_len > 0) {
                c1 = identify[offset_words * 2 + 1];
                c2 = identify[offset_words * 2];
                *dest = c1;
                dest++;
                *dest = c2;
                dest++;
                offset_words++;
                dest_len -= 2;
        }
}

static void disk_identify_fixup_string(
                uint8_t identify[512],
                unsigned offset_words,
                size_t len) {
        disk_identify_get_string(identify, offset_words,
                                 (char *) identify + offset_words * 2, len);
}

static void disk_identify_fixup_uint16 (uint8_t identify[512], unsigned offset_words) {
        uint16_t *p;

        p = (uint16_t *) identify;
        p[offset_words] = le16toh (p[offset_words]);
}

/**
 * disk_identify:
 * @fd: File descriptor for the block device.
 * @out_identify: Return location for IDENTIFY data.
 * @out_is_packet_device: Return location for whether returned data is from a IDENTIFY PACKET DEVICE.
 *
 * Sends the IDENTIFY DEVICE or IDENTIFY PACKET DEVICE command to the
 * device represented by @fd. If successful, then the result will be
 * copied into @out_identify and @out_is_packet_device.
 *
 * This routine is based on code from libatasmart, LGPL v2.1.
 *
 * Returns: 0 if the data was successfully obtained, otherwise
 * non-zero with errno set.
 */
static int disk_identify(int fd,
                         uint8_t out_identify[512],
                         int *out_is_packet_device) {
        int ret;
        uint8_t inquiry_buf[36];
        int peripheral_device_type;
        int all_nul_bytes;
        int n;
        int is_packet_device = 0;

        /* init results */
        memzero(out_identify, 512);

        /* If we were to use ATA PASS_THROUGH (12) on an ATAPI device
         * we could accidentally blank media. This is because MMC's BLANK
         * command has the same op-code (0x61).
         *
         * To prevent this from happening we bail out if the device
         * isn't a Direct Access Block Device, e.g. SCSI type 0x00
         * (CD/DVD devices are type 0x05). So we send a SCSI INQUIRY
         * command first... libata is handling this via its SCSI
         * emulation layer.
         *
         * This also ensures that we're actually dealing with a device
         * that understands SCSI commands.
         *
         * (Yes, it is a bit perverse that we're tunneling the ATA
         * command through SCSI and relying on the ATA driver
         * emulating SCSI well-enough...)
         *
         * (See commit 160b069c25690bfb0c785994c7c3710289179107 for
         * the original bug-fix and see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=556635
         * for the original bug-report.)
         */
        ret = disk_scsi_inquiry_command (fd, inquiry_buf, sizeof (inquiry_buf));
        if (ret != 0)
                goto out;

        /* SPC-4, section 6.4.2: Standard INQUIRY data */
        peripheral_device_type = inquiry_buf[0] & 0x1f;
        if (peripheral_device_type == 0x05)
          {
            is_packet_device = 1;
            ret = disk_identify_packet_device_command(fd, out_identify, 512);
            goto check_nul_bytes;
          }
        if (!IN_SET(peripheral_device_type, 0x00, 0x14)) {
                ret = -1;
                errno = EIO;
                goto out;
        }

        /* OK, now issue the IDENTIFY DEVICE command */
        ret = disk_identify_command(fd, out_identify, 512);
        if (ret != 0)
                goto out;

 check_nul_bytes:
         /* Check if IDENTIFY data is all NUL bytes - if so, bail */
        all_nul_bytes = 1;
        for (n = 0; n < 512; n++) {
                if (out_identify[n] != '\0') {
                        all_nul_bytes = 0;
                        break;
                }
        }

        if (all_nul_bytes) {
                ret = -1;
                errno = EIO;
                goto out;
        }

out:
        if (out_is_packet_device)
                *out_is_packet_device = is_packet_device;
        return ret;
}

int main(int argc, char *argv[]) {
        struct hd_driveid id;
        union {
                uint8_t  byte[512];
                uint16_t wyde[256];
        } identify;
        char model[41];
        char model_enc[256];
        char serial[21];
        char revision[9];
        const char *node = NULL;
        int export = 0;
        _cleanup_close_ int fd = -1;
        uint16_t word;
        int is_packet_device = 0;
        static const struct option options[] = {
                { "export", no_argument, NULL, 'x' },
                { "help", no_argument, NULL, 'h' },
                {}
        };

        log_set_target(LOG_TARGET_AUTO);
        udev_parse_config();
        log_parse_environment();
        log_open();

        for (;;) {
                int option;

                option = getopt_long(argc, argv, "xh", options, NULL);
                if (option == -1)
                        break;

                switch (option) {
                case 'x':
                        export = 1;
                        break;
                case 'h':
                        printf("Usage: %s [--export] [--help] <device>\n"
                               "  -x,--export    print values as environment keys\n"
                               "  -h,--help      print this help text\n\n",
                               program_invocation_short_name);
                        return 0;
                }
        }

        node = argv[optind];
        if (!node) {
                log_error("no node specified");
                return 1;
        }

        fd = open(node, O_RDONLY|O_NONBLOCK|O_CLOEXEC);
        if (fd < 0) {
                log_error("unable to open '%s'", node);
                return 1;
        }

        if (disk_identify(fd, identify.byte, &is_packet_device) == 0) {
                /*
                 * fix up only the fields from the IDENTIFY data that we are going to
                 * use and copy it into the hd_driveid struct for convenience
                 */
                disk_identify_fixup_string(identify.byte,  10, 20); /* serial */
                disk_identify_fixup_string(identify.byte,  23,  8); /* fwrev */
                disk_identify_fixup_string(identify.byte,  27, 40); /* model */
                disk_identify_fixup_uint16(identify.byte,  0);      /* configuration */
                disk_identify_fixup_uint16(identify.byte,  75);     /* queue depth */
                disk_identify_fixup_uint16(identify.byte,  76);     /* SATA capabilities */
                disk_identify_fixup_uint16(identify.byte,  82);     /* command set supported */
                disk_identify_fixup_uint16(identify.byte,  83);     /* command set supported */
                disk_identify_fixup_uint16(identify.byte,  84);     /* command set supported */
                disk_identify_fixup_uint16(identify.byte,  85);     /* command set supported */
                disk_identify_fixup_uint16(identify.byte,  86);     /* command set supported */
                disk_identify_fixup_uint16(identify.byte,  87);     /* command set supported */
                disk_identify_fixup_uint16(identify.byte,  89);     /* time required for SECURITY ERASE UNIT */
                disk_identify_fixup_uint16(identify.byte,  90);     /* time required for enhanced SECURITY ERASE UNIT */
                disk_identify_fixup_uint16(identify.byte,  91);     /* current APM values */
                disk_identify_fixup_uint16(identify.byte,  94);     /* current AAM value */
                disk_identify_fixup_uint16(identify.byte, 108);     /* WWN */
                disk_identify_fixup_uint16(identify.byte, 109);     /* WWN */
                disk_identify_fixup_uint16(identify.byte, 110);     /* WWN */
                disk_identify_fixup_uint16(identify.byte, 111);     /* WWN */
                disk_identify_fixup_uint16(identify.byte, 128);     /* device lock function */
                disk_identify_fixup_uint16(identify.byte, 217);     /* nominal media rotation rate */
                memcpy(&id, identify.byte, sizeof id);
        } else {
                /* If this fails, then try HDIO_GET_IDENTITY */
                if (ioctl(fd, HDIO_GET_IDENTITY, &id) != 0) {
                        log_debug_errno(errno, "HDIO_GET_IDENTITY failed for '%s': %m", node);
                        return 2;
                }
        }

        memcpy(model, id.model, 40);
        model[40] = '\0';
        udev_util_encode_string(model, model_enc, sizeof(model_enc));
        udev_replace_whitespace((char *) id.model, model, 40);
        util_replace_chars(model, NULL);
        udev_replace_whitespace((char *) id.serial_no, serial, 20);
        util_replace_chars(serial, NULL);
        udev_replace_whitespace((char *) id.fw_rev, revision, 8);
        util_replace_chars(revision, NULL);

        if (export) {
                /* Set this to convey the disk speaks the ATA protocol */
                printf("ID_ATA=1\n");

                if ((id.config >> 8) & 0x80) {
                        /* This is an ATAPI device */
                        switch ((id.config >> 8) & 0x1f) {
                        case 0:
                                printf("ID_TYPE=cd\n");
                                break;
                        case 1:
                                printf("ID_TYPE=tape\n");
                                break;
                        case 5:
                                printf("ID_TYPE=cd\n");
                                break;
                        case 7:
                                printf("ID_TYPE=optical\n");
                                break;
                        default:
                                printf("ID_TYPE=generic\n");
                                break;
                        }
                } else
                        printf("ID_TYPE=disk\n");
                printf("ID_BUS=ata\n");
                printf("ID_MODEL=%s\n", model);
                printf("ID_MODEL_ENC=%s\n", model_enc);
                printf("ID_REVISION=%s\n", revision);
                if (serial[0] != '\0') {
                        printf("ID_SERIAL=%s_%s\n", model, serial);
                        printf("ID_SERIAL_SHORT=%s\n", serial);
                } else
                        printf("ID_SERIAL=%s\n", model);

                if (id.command_set_1 & (1<<5)) {
                        printf("ID_ATA_WRITE_CACHE=1\n");
                        printf("ID_ATA_WRITE_CACHE_ENABLED=%d\n", (id.cfs_enable_1 & (1<<5)) ? 1 : 0);
                }
                if (id.command_set_1 & (1<<10)) {
                        printf("ID_ATA_FEATURE_SET_HPA=1\n");
                        printf("ID_ATA_FEATURE_SET_HPA_ENABLED=%d\n", (id.cfs_enable_1 & (1<<10)) ? 1 : 0);

                        /*
                         * TODO: use the READ NATIVE MAX ADDRESS command to get the native max address
                         * so it is easy to check whether the protected area is in use.
                         */
                }
                if (id.command_set_1 & (1<<3)) {
                        printf("ID_ATA_FEATURE_SET_PM=1\n");
                        printf("ID_ATA_FEATURE_SET_PM_ENABLED=%d\n", (id.cfs_enable_1 & (1<<3)) ? 1 : 0);
                }
                if (id.command_set_1 & (1<<1)) {
                        printf("ID_ATA_FEATURE_SET_SECURITY=1\n");
                        printf("ID_ATA_FEATURE_SET_SECURITY_ENABLED=%d\n", (id.cfs_enable_1 & (1<<1)) ? 1 : 0);
                        printf("ID_ATA_FEATURE_SET_SECURITY_ERASE_UNIT_MIN=%d\n", id.trseuc * 2);
                        if ((id.cfs_enable_1 & (1<<1))) /* enabled */ {
                                if (id.dlf & (1<<8))
                                        printf("ID_ATA_FEATURE_SET_SECURITY_LEVEL=maximum\n");
                                else
                                        printf("ID_ATA_FEATURE_SET_SECURITY_LEVEL=high\n");
                        }
                        if (id.dlf & (1<<5))
                                printf("ID_ATA_FEATURE_SET_SECURITY_ENHANCED_ERASE_UNIT_MIN=%d\n", id.trsEuc * 2);
                        if (id.dlf & (1<<4))
                                printf("ID_ATA_FEATURE_SET_SECURITY_EXPIRE=1\n");
                        if (id.dlf & (1<<3))
                                printf("ID_ATA_FEATURE_SET_SECURITY_FROZEN=1\n");
                        if (id.dlf & (1<<2))
                                printf("ID_ATA_FEATURE_SET_SECURITY_LOCKED=1\n");
                }
                if (id.command_set_1 & (1<<0)) {
                        printf("ID_ATA_FEATURE_SET_SMART=1\n");
                        printf("ID_ATA_FEATURE_SET_SMART_ENABLED=%d\n", (id.cfs_enable_1 & (1<<0)) ? 1 : 0);
                }
                if (id.command_set_2 & (1<<9)) {
                        printf("ID_ATA_FEATURE_SET_AAM=1\n");
                        printf("ID_ATA_FEATURE_SET_AAM_ENABLED=%d\n", (id.cfs_enable_2 & (1<<9)) ? 1 : 0);
                        printf("ID_ATA_FEATURE_SET_AAM_VENDOR_RECOMMENDED_VALUE=%d\n", id.acoustic >> 8);
                        printf("ID_ATA_FEATURE_SET_AAM_CURRENT_VALUE=%d\n", id.acoustic & 0xff);
                }
                if (id.command_set_2 & (1<<5)) {
                        printf("ID_ATA_FEATURE_SET_PUIS=1\n");
                        printf("ID_ATA_FEATURE_SET_PUIS_ENABLED=%d\n", (id.cfs_enable_2 & (1<<5)) ? 1 : 0);
                }
                if (id.command_set_2 & (1<<3)) {
                        printf("ID_ATA_FEATURE_SET_APM=1\n");
                        printf("ID_ATA_FEATURE_SET_APM_ENABLED=%d\n", (id.cfs_enable_2 & (1<<3)) ? 1 : 0);
                        if ((id.cfs_enable_2 & (1<<3)))
                                printf("ID_ATA_FEATURE_SET_APM_CURRENT_VALUE=%d\n", id.CurAPMvalues & 0xff);
                }
                if (id.command_set_2 & (1<<0))
                        printf("ID_ATA_DOWNLOAD_MICROCODE=1\n");

                /*
                 * Word 76 indicates the capabilities of a SATA device. A PATA device shall set
                 * word 76 to 0000h or FFFFh. If word 76 is set to 0000h or FFFFh, then
                 * the device does not claim compliance with the Serial ATA specification and words
                 * 76 through 79 are not valid and shall be ignored.
                 */

                word = identify.wyde[76];
                if (!IN_SET(word, 0x0000, 0xffff)) {
                        printf("ID_ATA_SATA=1\n");
                        /*
                         * If bit 2 of word 76 is set to one, then the device supports the Gen2
                         * signaling rate of 3.0 Gb/s (see SATA 2.6).
                         *
                         * If bit 1 of word 76 is set to one, then the device supports the Gen1
                         * signaling rate of 1.5 Gb/s (see SATA 2.6).
                         */
                        if (word & (1<<2))
                                printf("ID_ATA_SATA_SIGNAL_RATE_GEN2=1\n");
                        if (word & (1<<1))
                                printf("ID_ATA_SATA_SIGNAL_RATE_GEN1=1\n");
                }

                /* Word 217 indicates the nominal media rotation rate of the device */
                word = identify.wyde[217];
                if (word == 0x0001)
                        printf ("ID_ATA_ROTATION_RATE_RPM=0\n"); /* non-rotating e.g. SSD */
                else if (word >= 0x0401 && word <= 0xfffe)
                        printf ("ID_ATA_ROTATION_RATE_RPM=%d\n", word);

                /*
                 * Words 108-111 contain a mandatory World Wide Name (WWN) in the NAA IEEE Registered identifier
                 * format. Word 108 bits (15:12) shall contain 5h, indicating that the naming authority is IEEE.
                 * All other values are reserved.
                 */
                word = identify.wyde[108];
                if ((word & 0xf000) == 0x5000) {
                        uint64_t wwwn;

                        wwwn   = identify.wyde[108];
                        wwwn <<= 16;
                        wwwn  |= identify.wyde[109];
                        wwwn <<= 16;
                        wwwn  |= identify.wyde[110];
                        wwwn <<= 16;
                        wwwn  |= identify.wyde[111];
                        printf("ID_WWN=0x%1$" PRIx64 "\n"
                               "ID_WWN_WITH_EXTENSION=0x%1$" PRIx64 "\n",
                               wwwn);
                }

                /* from Linux's include/linux/ata.h */
                if (IN_SET(identify.wyde[0], 0x848a, 0x844a) ||
                    (identify.wyde[83] & 0xc004) == 0x4004)
                        printf("ID_ATA_CFA=1\n");
        } else {
                if (serial[0] != '\0')
                        printf("%s_%s\n", model, serial);
                else
                        printf("%s\n", model);
        }

        return 0;
}