/*
* os_linux.c
*
* Home page of code is: http://smartmontools.sourceforge.net
*
* Copyright (C) 2003 Bruce Allen <smartmontools-support@lists.sourceforge.net>
* Copyright (C) 2003 Doug Gilbert <dougg@torque.net>
*
* Parts of this file are derived from code that was
*
* Written By: Adam Radford <linux@3ware.com>
* Modifications By: Joel Jacobson <linux@3ware.com>
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
* Brad Strand <linux@3ware.com>
*
* Copyright (C) 1999-2003 3ware Inc.
*
* Kernel compatablity By: Andre Hedrick <andre@suse.com>
* Non-Copyright (C) 2000 Andre Hedrick <andre@suse.com>
*
* Other ars of this file are derived from code that was
*
* Copyright (C) 1999-2000 Michael Cornwell <cornwell@acm.org>
* Copyright (C) 2000 Andre Hedrick <andre@linux-ide.org>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* (for example COPYING); if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* This code was originally developed as a Senior Thesis by Michael Cornwell
* at the Concurrent Systems Laboratory (now part of the Storage Systems
* Research Center), Jack Baskin School of Engineering, University of
* California, Santa Cruz. http://ssrc.soe.ucsc.edu/
*
*/
// This file contains the linux-specific IOCTL parts of
// smartmontools. It includes one interface routine for ATA devices,
// one for SCSI devices, and one for ATA devices behind escalade
// controllers.
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <scsi/scsi_ioctl.h>
#include "atacmds.h"
#include "config.h"
#include "os_linux.h"
#include "scsicmds.h"
#include "smartd.h"
#include "utility.h"
const char *os_XXXX_c_cvsid="$Id: os_linux.cpp,v 1.9 2003/10/14 14:22:44 ballen4705 Exp $" \
ATACMDS_H_CVSID CONFIG_H_CVSID OS_XXXX_H_CVSID SCSICMDS_H_CVSID SMARTD_H_CVSID UTILITY_H_CVSID;
// to hold onto exit code for atexit routine
extern int exitstatus;
// keep track of memory allocated/deallocated
extern long long bytes;
// equivalent to open(path, flags)
int deviceopen(const char *pathname, char *type){
if (!strcmp(type,"SCSI"))
return open(pathname, O_RDWR | O_NONBLOCK);
else if (!strcmp(type,"ATA"))
return open(pathname, O_RDONLY | O_NONBLOCK);
else
return -1;
}
// equivalent to close(file descriptor)
int deviceclose(int fd){
return close(fd);
}
// makes a list of device names to scan, for either ATA or SCSI
// devices. Return -1 if no memory remaining, else the number of
// devices on the list, which can be >=0.
int make_device_names (char*** devlist, const char* name) {
char* base=NULL;
char** tmp=NULL;
int i, n=0;
// set correct first name (base name) for ATA or SCSI devices
if (!strcmp(name,"SCSI")) {
n = MAXSCSIDEVICES;
base = CustomStrDup("/dev/sda",1,__LINE__);
}
else if (!strcmp(name,"ATA")) {
n = MAXATADEVICES;
base = CustomStrDup("/dev/hda",1,__LINE__);
}
// bad type or no devices
if (!n)
return 0;
// allocate storage for the list of device names that we'll be
// making, and store first name
if (!(tmp = *devlist = (char **)calloc(n, sizeof(char *))))
return -1;
bytes += n*sizeof(char*);
tmp[0]=base;
// make device names by incrementing the last letter of the base
// name alphabetically a->b->c...
for (i = 1; i < n; i++) {
tmp[i] = CustomStrDup(tmp[i-1],1,__LINE__);
tmp[i][7]++;
}
return n;
}
// PURPOSE
// This is an interface routine meant to isolate the OS dependent
// parts of the code, and to provide a debugging interface. Each
// different port and OS needs to provide it's own interface. This
// is the linux one.
// DETAILED DESCRIPTION OF ARGUMENTS
// device: is the file descriptor provided by open()
// command: defines the different operations.
// select: additional input data if needed (which log, which type of
// self-test).
// data: location to write output data, if needed (512 bytes).
// Note: not all commands use all arguments.
// RETURN VALUES
// -1 if the command failed
// 0 if the command succeeded,
// STATUS_CHECK routine:
// -1 if the command failed
// 0 if the command succeeded and disk SMART status is "OK"
// 1 if the command succeeded and disk SMART status is "FAILING"
// huge value of buffer size needed because HDIO_DRIVE_CMD assumes
// that buff[3] is the data size. Since the SMART_AUTOSAVE and
// SMART_AUTO_OFFLINE use values of 0xf1 and 0xf8 we need the space.
// Otherwise a 4+512 byte buffer would be enough.
#define STRANGE_BUFFER_LENGTH (4+512*0xf8)
int ata_command_interface(int device, smart_command_set command, int select, char *data){
unsigned char buff[STRANGE_BUFFER_LENGTH];
int retval, copydata=0;
// The two linux IOCTL's that we use. These MUST be consistent with
// the same quantities in the kernel include file linux/hdreg.h
const int HDIO_DRIVE_TASK = 0x031e;
const int HDIO_DRIVE_CMD = 0x031f;
const int HDIO_DRIVE_CMD_OFFSET = 4;
// See struct hd_drive_cmd_hdr in hdreg.h
// buff[0]: ATA COMMAND CODE REGISTER
// buff[1]: ATA SECTOR NUMBER REGISTER == LBA LOW REGISTER
// buff[2]: ATA FEATURES REGISTER
// buff[3]: ATA SECTOR COUNT REGISTER
// clear out buff. Large enough for HDIO_DRIVE_CMD (4+512 bytes)
memset(buff, 0, STRANGE_BUFFER_LENGTH);
buff[0]=WIN_SMART;
switch (command){
case READ_VALUES:
buff[2]=SMART_READ_VALUES;
copydata=buff[3]=1;
break;
case READ_THRESHOLDS:
buff[2]=SMART_READ_THRESHOLDS;
copydata=buff[1]=buff[3]=1;
break;
case READ_LOG:
buff[2]=SMART_READ_LOG_SECTOR;
buff[1]=select;
copydata=buff[3]=1;
break;
case IDENTIFY:
buff[0]=WIN_IDENTIFY;
copydata=buff[3]=1;
break;
case PIDENTIFY:
buff[0]=WIN_PIDENTIFY;
copydata=buff[3]=1;
break;
case ENABLE:
buff[2]=SMART_ENABLE;
buff[1]=1;
break;
case DISABLE:
buff[2]=SMART_DISABLE;
buff[1]=1;
break;
case STATUS:
// this command only says if SMART is working. It could be
// replaced with STATUS_CHECK below.
buff[2]=SMART_STATUS;
break;
case AUTO_OFFLINE:
buff[2]=SMART_AUTO_OFFLINE;
buff[3]=select; // YET NOTE - THIS IS A NON-DATA COMMAND!!
break;
case AUTOSAVE:
buff[2]=SMART_AUTOSAVE;
buff[3]=select; // YET NOTE - THIS IS A NON-DATA COMMAND!!
break;
case IMMEDIATE_OFFLINE:
buff[2]=SMART_IMMEDIATE_OFFLINE;
buff[1]=select;
break;
case STATUS_CHECK:
// This command uses HDIO_DRIVE_TASK and has different syntax than
// the other commands.
buff[1]=SMART_STATUS;
break;
default:
pout("Unrecognized command %d in linux_ata_command_interface()\n"
"Please contact " PACKAGE_BUGREPORT "\n", command);
errno=ENOSYS;
return -1;
}
// There are two different types of ioctls(). The HDIO_DRIVE_TASK
// one is this:
if (command==STATUS_CHECK){
// NOT DOCUMENTED in /usr/src/linux/include/linux/hdreg.h. You
// have to read the IDE driver source code. Sigh.
// buff[0]: ATA COMMAND CODE REGISTER
// buff[1]: ATA FEATURES REGISTER
// buff[2]: ATA SECTOR_COUNT
// buff[3]: ATA SECTOR NUMBER
// buff[4]: ATA CYL LO REGISTER
// buff[5]: ATA CYL HI REGISTER
// buff[6]: ATA DEVICE HEAD
unsigned const char normal_lo=0x4f, normal_hi=0xc2;
unsigned const char failed_lo=0xf4, failed_hi=0x2c;
buff[4]=normal_lo;
buff[5]=normal_hi;
if ((retval=ioctl(device, HDIO_DRIVE_TASK, buff)))
return -1;
// Cyl low and Cyl high unchanged means "Good SMART status"
if (buff[4]==normal_lo && buff[5]==normal_hi)
return 0;
// These values mean "Bad SMART status"
if (buff[4]==failed_lo && buff[5]==failed_hi)
return 1;
// We haven't gotten output that makes sense; print out some debugging info
syserror("Error SMART Status command failed");
pout("Please get assistance from %s\n",PROJECTHOME);
pout("Register values returned from SMART Status command are:\n");
pout("CMD=0x%02x\n",(int)buff[0]);
pout("FR =0x%02x\n",(int)buff[1]);
pout("NS =0x%02x\n",(int)buff[2]);
pout("SC =0x%02x\n",(int)buff[3]);
pout("CL =0x%02x\n",(int)buff[4]);
pout("CH =0x%02x\n",(int)buff[5]);
pout("SEL=0x%02x\n",(int)buff[6]);
return -1;
}
#if (1)
// Note to people doing ports to other OSes -- don't worry about
// this block -- you can ignore it. I have put it here because
// under linux when you do IDENTIFY DEVICE to a packet device, it
// generates an ugly kernel syslog error message. This is harmless
// but frightens users. So this block is an attempt to detect
// packet devices and make IDENTIFY DEVICE fail "nicely" without a
// syslog error message.
// This doesn't always work, since ATA-3 did not have a separate
// IDENTIFY PACKET DEVICE command. In fact while ATAPI was
// introduced in ATA-3, IDENTIFY PACKET DEVICE only appeared in ATA
// 4 revision 2. Anyway, this doesn't matter, since packet devices
// don't support SMART anyway.
// for IDENTIFY command, check if device is a packet device, and if
// it is, then we simulate a 'clean' error without calling the
// lower-level ioctl that will generate a kernel error log message.
if (command==IDENTIFY){
unsigned char junk[512];
const int HDIO_GET_IDENTITY=0x030d;
if (!ioctl(device, HDIO_GET_IDENTITY, junk) && (junk[1]>>7)) {
// device is PACKET device
errno = 5;
return -1;
}
}
#endif
// We are now doing the HDIO_DRIVE_CMD type ioctl.
if ((retval=ioctl(device, HDIO_DRIVE_CMD, buff)))
return -1;
// if the command returns data, copy it back
if (copydata)
memcpy(data, buff+HDIO_DRIVE_CMD_OFFSET, 512);
return 0;
}
/* SCSI command transmission interface function, implementation is OS
* specific. Returns 0 if SCSI command successfully launched and response
* received, else returns a negative errno value */
/* Linux specific code, FreeBSD could conditionally compile in CAM stuff
* instead of this. */
/* #include <scsi/scsi.h> bypass for now */
/* #include <scsi/scsi_ioctl.h> bypass for now */
#define MAX_DXFER_LEN 1024 /* can be increased if necessary */
#define SEND_IOCTL_RESP_SENSE_LEN 16 /* ioctl limitation */
#define DRIVER_SENSE 0x8 /* alternate CHECK CONDITION indication */
#ifndef SCSI_IOCTL_SEND_COMMAND
#define SCSI_IOCTL_SEND_COMMAND 1
#endif
#ifndef SCSI_IOCTL_TEST_UNIT_READY
#define SCSI_IOCTL_TEST_UNIT_READY 2
#endif
struct linux_ioctl_send_command
{
int inbufsize;
int outbufsize;
UINT8 buff[MAX_DXFER_LEN + 16];
};
/* The Linux SCSI_IOCTL_SEND_COMMAND ioctl is primitive and it doesn't
* support: CDB length (guesses it from opcode), resid and timeout.
* Patches in Linux 2.4.21 and 2.5.70 to extend SEND DIAGNOSTIC timeout
* to 2 hours in order to allow long foreground extended self tests. */
int do_scsi_cmnd_io(int dev_fd, struct scsi_cmnd_io * iop, int report)
{
struct linux_ioctl_send_command wrk;
int status, buff_offset;
size_t len;
memcpy(wrk.buff, iop->cmnd, iop->cmnd_len);
buff_offset = iop->cmnd_len;
if (report > 0) {
int k;
const unsigned char * ucp = iop->cmnd;
const char * np;
np = scsi_get_opcode_name(ucp[0]);
pout(" [%s: ", np ? np : "<unknown opcode>");
for (k = 0; k < iop->cmnd_len; ++k)
pout("%02x ", ucp[k]);
if ((report > 1) &&
(DXFER_TO_DEVICE == iop->dxfer_dir) && (iop->dxferp)) {
int trunc = (iop->dxfer_len > 256) ? 1 : 0;
pout("]\n Outgoing data, len=%d%s:\n", (int)iop->dxfer_len,
(trunc ? " [only first 256 bytes shown]" : ""));
dStrHex(iop->dxferp, (trunc ? 256 : iop->dxfer_len) , 1);
}
else
pout("]");
}
switch (iop->dxfer_dir) {
case DXFER_NONE:
wrk.inbufsize = 0;
wrk.outbufsize = 0;
break;
case DXFER_FROM_DEVICE:
wrk.inbufsize = 0;
if (iop->dxfer_len > MAX_DXFER_LEN)
return -EINVAL;
wrk.outbufsize = iop->dxfer_len;
break;
case DXFER_TO_DEVICE:
if (iop->dxfer_len > MAX_DXFER_LEN)
return -EINVAL;
memcpy(wrk.buff + buff_offset, iop->dxferp, iop->dxfer_len);
wrk.inbufsize = iop->dxfer_len;
wrk.outbufsize = 0;
break;
default:
pout("do_scsi_cmnd_io: bad dxfer_dir\n");
return -EINVAL;
}
iop->resp_sense_len = 0;
iop->scsi_status = 0;
iop->resid = 0;
status = ioctl(dev_fd, SCSI_IOCTL_SEND_COMMAND , &wrk);
if (-1 == status) {
if (report)
pout(" status=-1, errno=%d [%s]\n", errno, strerror(errno));
return -errno;
}
if (0 == status) {
if (report > 0)
pout(" status=0\n");
if (DXFER_FROM_DEVICE == iop->dxfer_dir) {
memcpy(iop->dxferp, wrk.buff, iop->dxfer_len);
if (report > 1) {
int trunc = (iop->dxfer_len > 256) ? 1 : 0;
pout(" Incoming data, len=%d%s:\n", (int)iop->dxfer_len,
(trunc ? " [only first 256 bytes shown]" : ""));
dStrHex(iop->dxferp, (trunc ? 256 : iop->dxfer_len) , 1);
}
}
return 0;
}
iop->scsi_status = status & 0x7e; /* bits 0 and 7 used to be for vendors */
if (DRIVER_SENSE == ((status >> 24) & 0xf))
iop->scsi_status = SCSI_STATUS_CHECK_CONDITION;
len = (SEND_IOCTL_RESP_SENSE_LEN < iop->max_sense_len) ?
SEND_IOCTL_RESP_SENSE_LEN : iop->max_sense_len;
if ((SCSI_STATUS_CHECK_CONDITION == iop->scsi_status) &&
iop->sensep && (len > 0)) {
memcpy(iop->sensep, wrk.buff, len);
iop->resp_sense_len = len;
if (report > 1) {
pout(" >>> Sense buffer, len=%d:\n", (int)len);
dStrHex(wrk.buff, len , 1);
}
}
if (report) {
if (SCSI_STATUS_CHECK_CONDITION == iop->scsi_status) {
pout(" status=%x: sense_key=%x asc=%x ascq=%x\n", status & 0xff,
wrk.buff[2] & 0xf, wrk.buff[12], wrk.buff[13]);
}
else
pout(" status=0x%x\n", status);
}
if (iop->scsi_status > 0)
return 0;
else {
if (report > 0)
pout(" ioctl status=0x%x but scsi status=0, fail with EIO\n",
status);
return -EIO; /* give up, assume no device there */
}
}
void printwarning(smart_command_set command);
// PURPOSE
// This is an interface routine meant to isolate the OS dependent
// parts of the code, and to provide a debugging interface. Each
// different port and OS needs to provide it's own interface. This
// is the linux interface to the 3ware 3w-xxxx driver. It allows ATA
// commands to be passed through the SCSI driver.
// DETAILED DESCRIPTION OF ARGUMENTS
// fd: is the file descriptor provided by open()
// disknum is the disk number (0 to 15) in the RAID array
// command: defines the different operations.
// select: additional input data if needed (which log, which type of
// self-test).
// data: location to write output data, if needed (512 bytes).
// Note: not all commands use all arguments.
// RETURN VALUES
// -1 if the command failed
// 0 if the command succeeded,
// STATUS_CHECK routine:
// -1 if the command failed
// 0 if the command succeeded and disk SMART status is "OK"
// 1 if the command succeeded and disk SMART status is "FAILING"
int escalade_command_interface(int fd, int disknum, smart_command_set command, int select, char *data){
// Structures for passing commands through 3Ware Escalade Linux Driver
TW_Ioctl ioctlbuf;
TW_Passthru passthru;
// If command returns 512 bytes, set to 1, else 0
int readdata=0;
// Clear out the data structures
memset (&ioctlbuf, 0, sizeof(TW_Ioctl));
memset (&passthru, 0, sizeof(TW_Passthru));
// Same for (almost) all commands - but some reset below
passthru.byte0.opcode = 0x11;
passthru.request_id = 0xFF;
passthru.byte3.aport = disknum;
passthru.byte3.host_id = 0;
passthru.status = 0;
passthru.flags = 0x1;
passthru.drive_head = 0x0;
passthru.sector_num = 0;
// All SMART commands use this CL/CH signature. These are magic
// values from the ATA specifications.
passthru.cylinder_lo = 0x4F;
passthru.cylinder_hi = 0xC2;
// SMART ATA COMMAND REGISTER value
passthru.command = WIN_SMART;
// Is this a command that returns 512 bytes?
if (command == READ_VALUES ||
command == READ_THRESHOLDS ||
command == READ_LOG ||
command == IDENTIFY) {
readdata=1;
passthru.byte0.sgloff = 0x5;
passthru.size = 0x7;
passthru.param = 0xD;
passthru.sector_count = 0x1;
}
else {
// Non data command -- but doesn't use large sector
// count register values. passthru.param values are:
// 0x00 - non data command without TFR write check,
// 0x08 - non data command with TFR write check,
passthru.byte0.sgloff = 0x0;
passthru.size = 0x5;
passthru.param = 0x8;
passthru.sector_count = 0x0;
}
// Now set ATA registers depending upon command
switch (command){
case READ_VALUES:
passthru.features = SMART_READ_VALUES;
break;
case READ_THRESHOLDS:
passthru.features = SMART_READ_THRESHOLDS;
break;
case READ_LOG:
passthru.features = SMART_READ_LOG_SECTOR;
// log number to return
passthru.sector_num = select;
break;
case IDENTIFY:
// ATA IDENTIFY DEVICE
passthru.command = 0xEc;
passthru.features = 0;
passthru.cylinder_lo = 0;
passthru.cylinder_hi = 0;
break;
case PIDENTIFY:
// 3WARE controller can NOT have packet device internally
pout("WARNING - NO DEVICE FOUND ON 3WARE CONTROLLER (disk %d)\n", disknum);
errno=ENODEV;
return -1;
case ENABLE:
passthru.features = SMART_ENABLE;
break;
case DISABLE:
passthru.features = SMART_DISABLE;
break;
case AUTO_OFFLINE:
passthru.features = SMART_AUTO_OFFLINE;
// Enable or disable?
passthru.sector_count = select;
break;
case AUTOSAVE:
passthru.features = SMART_AUTOSAVE;
// Enable or disable?
passthru.sector_count = select;
break;
case IMMEDIATE_OFFLINE:
passthru.features = SMART_IMMEDIATE_OFFLINE;
// What test type to run?
passthru.sector_num = select;
break;
case STATUS_CHECK:
passthru.features = SMART_STATUS;
break;
case STATUS:
// This is JUST to see if SMART is enabled, by giving SMART status
// command. But it doesn't say if status was good, or failing.
// See below for the difference.
passthru.features = SMART_STATUS;
break;
default:
pout("Unrecognized command %d in linux_3ware_command_interface(disk %d)\n"
"Please contact " PACKAGE_BUGREPORT "\n", command, disknum);
errno=ENOSYS;
return -1;
}
/* Copy the passthru command into the ioctl input buffer */
memcpy(&ioctlbuf.input_data, &passthru, sizeof(TW_Passthru));
ioctlbuf.cdb[0] = TW_IOCTL;
ioctlbuf.opcode = TW_ATA_PASSTHRU;
// CHECKME -- IS THIS RIGHT?? Even for non data I/O commands?
ioctlbuf.input_length = 512;
ioctlbuf.output_length = 512;
/* Now send the command down through an ioctl() */
if (ioctl(fd, SCSI_IOCTL_SEND_COMMAND, &ioctlbuf)) {
// If error was provoked by driver, tell user how to fix it
if ((command==AUTO_OFFLINE || command==AUTOSAVE) && select){
printwarning(command);
errno=ENOTSUP;
}
return -1;
}
// If this is a read data command, copy data to output buffer
if (readdata){
TW_Output *tw_output=(TW_Output *)&ioctlbuf;
memcpy(data, tw_output->output_data, 512);
}
// We are finished with all commands except for STATUS_CHECK
if (command!=STATUS_CHECK) {
return 0;
}
else {
// To find out if the SMART RETURN STATUS is good or failing, we
// need to examine the values of the Cylinder Low and Cylinder
// High Registers.
TW_Output *tw_output=(TW_Output *)&ioctlbuf;
TW_Passthru *tw_passthru_returned=(TW_Passthru *)&(tw_output->output_data);
unsigned short cyl_lo=tw_passthru_returned->cylinder_lo;
unsigned short cyl_hi=tw_passthru_returned->cylinder_hi;
// If values in Cyl-LO and Cyl-HI are unchanged, SMART status is good.
if (cyl_lo==0x4F && cyl_hi==0xC2)
return 0;
// If values in Cyl-LO and Cyl-HI are as follows, SMART status is FAIL
if (cyl_lo==0xF4 && cyl_hi==0x2C)
return 1;
// Any other values mean that something has gone wrong with the command
printwarning(command);
errno=ENOSYS;
return 0;
}
}
// Utility function for printing warnings
void printwarning(smart_command_set command){
static int printed1=0,printed2=0,printed3=0;
const char* message=
"can not be passed through the 3ware 3w-xxxx driver. This can be fixed by\n"
"applying a simple 3w-xxxx driver patch that can be found here:\n"
PROJECTHOME "\n"
"Alternatively, upgrade your 3w-xxxx driver to version 1.02.00.037 or greater.\n\n";
if (command==AUTO_OFFLINE && !printed1) {
printed1=1;
pout("The SMART AUTO-OFFLINE ENABLE command (smartmontools -o on option/Directive)\n%s", message);
}
else if (command==AUTOSAVE && !printed2) {
printed2=1;
pout("The SMART AUTOSAVE ENABLE command (smartmontools -S on option/Directive)\n%s", message);
}
else if (command==STATUS_CHECK && !printed3) {
printed3=1;
pout("The SMART RETURN STATUS return value (smartmontools -H option/Directive)\n%s", message);
}
return;
}
// Guess device type (ata or scsi) based on device name (Linux
// specific) SCSI device name in linux can be sd, sr, scd, st, nst,
// osst, nosst and sg.
static const char * lin_dev_prefix = "/dev/";
static const char * lin_dev_ata_disk_plus = "h";
static const char * lin_dev_ata_devfs_disk_plus = "ide/";
static const char * lin_dev_scsi_devfs_disk_plus = "scsi/";
static const char * lin_dev_scsi_disk_plus = "s";
static const char * lin_dev_scsi_tape1 = "ns";
static const char * lin_dev_scsi_tape2 = "os";
static const char * lin_dev_scsi_tape3 = "nos";
int guess_device_type(const char * dev_name) {
int len;
int dev_prefix_len = strlen(lin_dev_prefix);
// if dev_name null, or string length zero
if (!dev_name || !(len = strlen(dev_name)))
return GUESS_DEVTYPE_DONT_KNOW;
// Remove the leading /dev/... if it's there
if (!strncmp(lin_dev_prefix, dev_name, dev_prefix_len)) {
if (len <= dev_prefix_len)
// if nothing else in the string, unrecognized
return GUESS_DEVTYPE_DONT_KNOW;
// else advance pointer to following characters
dev_name += dev_prefix_len;
}
// form /dev/h* or h*
if (!strncmp(lin_dev_ata_disk_plus, dev_name,
strlen(lin_dev_ata_disk_plus)))
return GUESS_DEVTYPE_ATA;
// form /dev/ide/* or ide/*
if (!strncmp(lin_dev_ata_devfs_disk_plus, dev_name,
strlen(lin_dev_ata_devfs_disk_plus)))
return GUESS_DEVTYPE_ATA;
// form /dev/s* or s*
if (!strncmp(lin_dev_scsi_disk_plus, dev_name,
strlen(lin_dev_scsi_disk_plus)))
return GUESS_DEVTYPE_SCSI;
// form /dev/scsi/* or scsi/*
if (!strncmp(lin_dev_scsi_devfs_disk_plus, dev_name,
strlen(lin_dev_scsi_devfs_disk_plus)))
return GUESS_DEVTYPE_SCSI;
// form /dev/ns* or ns*
if (!strncmp(lin_dev_scsi_tape1, dev_name,
strlen(lin_dev_scsi_tape1)))
return GUESS_DEVTYPE_SCSI;
// form /dev/os* or os*
if (!strncmp(lin_dev_scsi_tape2, dev_name,
strlen(lin_dev_scsi_tape2)))
return GUESS_DEVTYPE_SCSI;
// form /dev/nos* or nos*
if (!strncmp(lin_dev_scsi_tape3, dev_name,
strlen(lin_dev_scsi_tape3)))
return GUESS_DEVTYPE_SCSI;
// we failed to recognize any of the forms
return GUESS_DEVTYPE_DONT_KNOW;
}