examples/scsi_inquiry.c

/*
 * Copyright (C) 1999-2018 D. Gilbert
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Test code for D. Gilbert's extensions to the Linux OS SCSI generic ("sg")
 * device driver.
 * This program does a SCSI inquiry command on the given device and
 * outputs some of the result. This program highlights the use of the
 * SCSI_IOCTL_SEND_COMMAND ioctl. This should be able to be applied to
 * any SCSI device file descriptor (not just one related to sg). [Whether
 * this is a good idea on a disk while it is mounted is debatable.
 * No detrimental effects when this was tested ...]
 *
 * Version 0.16 20181207
 */

#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <scsi/scsi.h>
/* #include <scsi/scsi_ioctl.h> */ /* glibc hides this file sometimes */

typedef struct my_scsi_ioctl_command {
        unsigned int inlen;  /* _excluding_ scsi command length */
        unsigned int outlen;
        unsigned char data[1];  /* was 0 but that's not ISO C!! */
                /* on input, scsi command starts here then opt. data */
} My_Scsi_Ioctl_Command;

#define OFF (2 * sizeof(unsigned int))

#ifndef SCSI_IOCTL_SEND_COMMAND
#define SCSI_IOCTL_SEND_COMMAND 1
#endif

#define INQUIRY_CMD     0x12
#define INQUIRY_CMDLEN  6
#define INQUIRY_REPLY_LEN 96


int main(int argc, char * argv[])
{
    int s_fd, res, k, to;
    unsigned char inq_cdb [INQUIRY_CMDLEN] = {INQUIRY_CMD, 0, 0, 0,
                                                INQUIRY_REPLY_LEN, 0};
    unsigned char * inqBuff = (unsigned char *)
                                malloc(OFF + sizeof(inq_cdb) + 512);
    unsigned char * buffp = inqBuff + OFF;
    My_Scsi_Ioctl_Command * ishp = (My_Scsi_Ioctl_Command *)inqBuff;
    char * file_name = 0;
    int do_nonblock = 0;
    int oflags = 0;

    for (k = 1; k < argc; ++k) {
        if (0 == strcmp(argv[k], "-n"))
            do_nonblock = 1;
        else if (*argv[k] != '-')
            file_name = argv[k];
        else {
            printf("Unrecognized argument '%s'\n", argv[k]);
            file_name = 0;
            break;
        }
    }
    if (0 == file_name) {
        printf("Usage: 'scsi_inquiry [-n] <scsi_device>'\n");
        printf("     where: -n   open device in non-blocking mode\n");
        printf("  Examples: scsi_inquiry /dev/sda\n");
        printf("            scsi_inquiry /dev/sg0\n");
        printf("            scsi_inquiry -n /dev/scd0\n");
        return 1;
    }

    if (do_nonblock)
        oflags = O_NONBLOCK;
    s_fd = open(file_name, oflags | O_RDWR);
    if (s_fd < 0) {
        if ((EROFS == errno) || (EACCES == errno)) {
            s_fd = open(file_name, oflags | O_RDONLY);
            if (s_fd < 0) {
                perror("scsi_inquiry: open error");
                return 1;
            }
        }
        else {
            perror("scsi_inquiry: open error");
            return 1;
        }
    }
    /* Don't worry, being very careful not to write to a none-scsi file ... */
    res = ioctl(s_fd, SCSI_IOCTL_GET_BUS_NUMBER, &to);
    if (res < 0) {
        /* perror("ioctl on scsi device, error"); */
        printf("scsi_inquiry: not a scsi device\n");
        return 1;
    }

    ishp->inlen = 0;
    ishp->outlen = INQUIRY_REPLY_LEN;
    memcpy(buffp, inq_cdb, INQUIRY_CMDLEN);
    res = ioctl(s_fd, SCSI_IOCTL_SEND_COMMAND, inqBuff);
    if (0 == res) {
        to = (int)*(buffp + 7);
        printf("    %.8s  %.16s  %.4s, byte_7=0x%x\n", buffp + 8,
               buffp + 16, buffp + 32, to);
    }
    else if (res < 0)
        perror("scsi_inquiry: SCSI_IOCTL_SEND_COMMAND err");
    else
        printf("scsi_inquiry: SCSI_IOCTL_SEND_COMMAND status=0x%x\n", res);

    res = close(s_fd);
    if (res < 0) {
        perror("scsi_inquiry: close error");
        return 1;
    }
    return 0;
}