scsi_ioctl.c

#include <inttypes.h>                                                                                                                                                                                                                
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <scsi/sg.h> /* take care: fetches glibc's /usr/include/scsi/sg.h */

/* This is a simple program executing a SCSI INQUIRY command using the
   sg_io_hdr interface of the SCSI generic (sg) driver.

*  Copyright (C) 2001 D. Gilbert
*  This program is free software.   Version 1.01 (20020226)
*/

#define INQ_REPLY_LEN 96
#define INQ_CMD_CODE 0x12
#define INQ_CMD_LEN 6

int execute_scsi_command(
        int fd, sg_io_hdr_t *io_hdr,
        int cmd_size,   uint8_t* cmd_buffer,
        int out_size,   uint8_t* out_buffer,
        int sense_size, uint8_t* sense_buffer)
{
    //Prepare SCSI Command
    memset(io_hdr, 0, sizeof(sg_io_hdr_t));

    io_hdr->interface_id = 'S'; //required

    io_hdr->cmd_len = cmd_size; 
    io_hdr->mx_sb_len = sense_size;

    /*  
     *  SG_DXFER_NONE   -   SCSI Test Unit Ready command
     *  SG_DXFER_TO_DEV -   SCSI WRITE command
     *  SG_DXFER_FROM_DEV - SCSI READ command
     */
    io_hdr->dxfer_direction = SG_DXFER_FROM_DEV;
    io_hdr->dxfer_len       = out_size;
    io_hdr->dxferp          = out_buffer; 

    io_hdr->cmdp = cmd_buffer;
    io_hdr->sbp  = sense_buffer;
    io_hdr->timeout = 20000; // 20000 millisecs = 20 seconds
    /* io_hdr.flags = 0; */     /* take defaults: indirect IO, etc */
    /* io_hdr.pack_id = 0; */
    /* io_hdr.usr_ptr = NULL; */

    if (ioctl(fd, SG_IO, io_hdr) < 0) {
        perror("sg_simple0: Inquiry SG_IO ioctl error");
        return 1;
    }

    return 0;
}


int inquiry(char * device_path)
{
    int sg_fd, k;
    unsigned char inqCmdBlk[INQ_CMD_LEN] = {INQ_CMD_CODE, 0, 0, 0, INQ_REPLY_LEN, 0};

/* This is a "standard" SCSI INQUIRY command. It is standard because the
 * CMDDT and EVPD bits (in the second byte) are zero. All SCSI targets
 * should respond promptly to a standard INQUIRY */

    unsigned char inqBuff[INQ_REPLY_LEN];
    unsigned char sense_buffer[32];

    if ((sg_fd = open(device_path, O_RDONLY)) < 0) {
        /* Note that most SCSI commands require the O_RDWR flag to be set */
        perror("error opening given file name");
        return 1;
    }

    sg_io_hdr_t io_hdr;

    execute_scsi_command(
      sg_fd, &io_hdr,
      INQ_CMD_LEN,inqCmdBlk,
      INQ_REPLY_LEN,inqBuff  ,
      32, sense_buffer
    );

    /* now for the error processing */
    if ((io_hdr.info & SG_INFO_OK_MASK) != SG_INFO_OK) {
        if (io_hdr.sb_len_wr > 0) {
            printf("INQUIRY sense data: ");
            for (k = 0; k < io_hdr.sb_len_wr; ++k) {
                if ((k > 0) && (0 == (k % 10)))
                    printf("\n  ");
                printf("0x%02x ", sense_buffer[k]);
            }
            printf("\n");
        }

        if (io_hdr.masked_status)
            printf("INQUIRY SCSI status=0x%x\n", io_hdr.status);
        if (io_hdr.host_status)
            printf("INQUIRY host_status=0x%x\n", io_hdr.host_status);
        if (io_hdr.driver_status)
            printf("INQUIRY driver_status=0x%x\n", io_hdr.driver_status);
    }
    else {  /* assume INQUIRY response is present */
        char * p = (char *)inqBuff;
        printf("Some of the INQUIRY command's response:\n");
        printf("    %.8s  %.16s  %.4s\n", p + 8, p + 16, p + 32);
        printf("INQUIRY duration=%u millisecs, resid=%d\n",
               io_hdr.duration, io_hdr.resid);
    }
    close(sg_fd);
    return 0;
}

int main(int argc, const char *argv[])
{

    inquiry("/dev/sda");
    return 0;
}