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/*
* Copyright (c) 2013-2014 Douglas Gilbert.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <iostream>
#include <vector>
#include <system_error>
#include <thread>
#include <mutex>
#include <chrono>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "sg_lib.h"
#include "sg_pt.h"
static const char * version_str = "1.07 20140828";
static const char * util_name = "sg_tst_excl2";
/* This is a test program for checking O_EXCL on open() works. It uses
* multiple threads and can be run as multiple processes and attempts
* to "break" O_EXCL. The strategy is to open a device O_EXCL|O_NONBLOCK
* and do a double increment on a LB then close it. Prior to the first
* increment, the value is checked for even or odd. Assuming the count
* starts as an even (typically 0) then it should remain even. Odd instances
* are counted and reported at the end of the program, after all threads
* have completed.
*
* This is C++ code with some things from C++11 (e.g. threads) and was
* only just able to compile (when some things were reverted) with gcc/g++
* version 4.7.3 found in Ubuntu 13.04 . C++11 "feature complete" support
* was not available until g++ version 4.8.1 and that is only currently
* found in Fedora 19 .
*
* The build uses various object files from the <sg3_utils>/lib directory
* which is assumed to be a sibling of this examples directory. Those
* object files in the lib directory can be built with:
* cd <sg3_utils> ; ./configure ; cd lib; make
* Then to build sg_tst_excl2 concatenate the next 3 lines:
* g++ -Wall -std=c++11 -pthread -I ../include ../lib/sg_lib.o
* ../lib/sg_lib_data.o ../lib/sg_pt_linux.o -o sg_tst_excl2
* sg_tst_excl2.cpp
* Alternatively use 'make -f Makefile.cplus sg_tst_excl2'
*
* BEWARE: this utility modifies a logical block (default LBA 1000) on the
* given device.
*
* Test breaks sg driver in lk 3.10.4 but works with proposed fix so should
* work soon thereafter. Works on standard block driver (e.g. /dev/sdc) in
* lk 3.10.4 . Fails on bsg driver in lk 3.10.4 because it ignores the
* O_EXCL flag (and that is unlikely to change).
*
*/
using namespace std;
using namespace std::chrono;
#define DEF_NUM_PER_THREAD 200
#define DEF_NUM_THREADS 4
#define DEF_WAIT_MS 0 /* 0: yield; -1: don't wait; -2: sleep(0) */
#define DEF_LBA 1000
#define EBUFF_SZ 256
static mutex odd_count_mutex;
static mutex console_mutex;
static unsigned int odd_count;
static unsigned int ebusy_count;
static void
usage(void)
{
printf("Usage: %s [-b] [-f] [-h] [-l <lba>] [-n <n_per_thr>] "
"[-t <num_thrs>]\n"
" [-V] [-w <wait_ms>] [-x] "
"<disk_device>\n", util_name);
printf(" where\n");
printf(" -b block on open (def: O_NONBLOCK)\n");
printf(" -f force: any SCSI disk (def: only "
"scsi_debug)\n");
printf(" WARNING: <lba> written to\n");
printf(" -h print this usage message then exit\n");
printf(" -l <lba> logical block to increment (def: %u)\n",
DEF_LBA);
printf(" -n <n_per_thr> number of loops per thread "
"(def: %d)\n", DEF_NUM_PER_THREAD);
printf(" -t <num_thrs> number of threads (def: %d)\n",
DEF_NUM_THREADS);
printf(" -V print version number then exit\n");
printf(" -w <wait_ms> >0: sleep_for(<wait_ms>); =0: "
"yield(); -1: no\n"
" wait; -2: sleep(0) (def: %d)\n",
DEF_WAIT_MS);
printf(" -x don't use O_EXCL on first thread "
"(def: use\n"
" O_EXCL on all threads)\n\n");
printf("Test O_EXCL open flag with pass-through drivers. Each "
"open/close cycle with\nthe O_EXCL flag does a double increment "
"on lba (using its first 4 bytes).\n");
}
/* Assumed a lock (mutex) held when pt_err() is called */
static int
pt_err(int res)
{
if (res < 0)
fprintf(stderr, " pass through os error: %s\n", safe_strerror(-res));
else if (SCSI_PT_DO_BAD_PARAMS == res)
fprintf(stderr, " bad pass through setup\n");
else if (SCSI_PT_DO_TIMEOUT == res)
fprintf(stderr, " pass through timeout\n");
else
fprintf(stderr, " do_scsi_pt error=%d\n", res);
return -1;
}
/* Assumed a lock (mutex) held when pt_cat_no_good() is called */
static int
pt_cat_no_good(int cat, struct sg_pt_base * ptp, const unsigned char * sbp)
{
int slen;
char b[256];
const int bl = (int)sizeof(b);
switch (cat) {
case SCSI_PT_RESULT_STATUS: /* other than GOOD and CHECK CONDITION */
sg_get_scsi_status_str(get_scsi_pt_status_response(ptp), bl, b);
fprintf(stderr, " scsi status: %s\n", b);
break;
case SCSI_PT_RESULT_SENSE:
slen = get_scsi_pt_sense_len(ptp);
sg_get_sense_str("", sbp, slen, 1, bl, b);
fprintf(stderr, "%s", b);
break;
case SCSI_PT_RESULT_TRANSPORT_ERR:
get_scsi_pt_transport_err_str(ptp, bl, b);
fprintf(stderr, " transport: %s", b);
break;
case SCSI_PT_RESULT_OS_ERR:
get_scsi_pt_os_err_str(ptp, bl, b);
fprintf(stderr, " os: %s", b);
break;
default:
fprintf(stderr, " unknown pt result category (%d)\n", cat);
break;
}
return -1;
}
#define READ16_REPLY_LEN 512
#define READ16_CMD_LEN 16
#define WRITE16_REPLY_LEN 512
#define WRITE16_CMD_LEN 16
/* Opens dev_name and spins if busy (i.e. gets EBUSY), sleeping for
* wait_ms milliseconds if wait_ms is positive. Reads lba and treats the
* first 4 bytes as an int (SCSI endian), increments it and writes it back.
* Repeats so that happens twice. Then closes dev_name. If an error occurs
* returns -1 else returns 0 if first int read is even otherwise returns 1. */
static int
do_rd_inc_wr_twice(const char * dev_name, unsigned int lba, int block,
int excl, int wait_ms, unsigned int & ebusys)
{
int k, sg_fd, res, cat;
int odd = 0;
unsigned int u = 0;
struct sg_pt_base * ptp = NULL;
unsigned char r16CmdBlk [READ16_CMD_LEN] =
{0x88, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0};
unsigned char w16CmdBlk [WRITE16_CMD_LEN] =
{0x8a, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0};
unsigned char sense_buffer[64];
unsigned char lb[READ16_REPLY_LEN];
char ebuff[EBUFF_SZ];
int open_flags = O_RDWR;
r16CmdBlk[6] = w16CmdBlk[6] = (lba >> 24) & 0xff;
r16CmdBlk[7] = w16CmdBlk[7] = (lba >> 16) & 0xff;
r16CmdBlk[8] = w16CmdBlk[8] = (lba >> 8) & 0xff;
r16CmdBlk[9] = w16CmdBlk[9] = lba & 0xff;
if (! block)
open_flags |= O_NONBLOCK;
if (excl)
open_flags |= O_EXCL;
while (((sg_fd = scsi_pt_open_flags(dev_name, open_flags, 0)) < 0) &&
(-EBUSY == sg_fd)) {
++ebusys;
if (wait_ms > 0)
this_thread::sleep_for(milliseconds{wait_ms});
else if (0 == wait_ms)
this_thread::yield(); // thread yield
else if (-2 == wait_ms)
sleep(0); // process yield ??
}
if (sg_fd < 0) {
snprintf(ebuff, EBUFF_SZ,
"do_rd_inc_wr_twice: error opening file: %s", dev_name);
{
lock_guard<mutex> lg(console_mutex);
perror(ebuff);
}
return -1;
}
ptp = construct_scsi_pt_obj();
for (k = 0; k < 2; ++k) {
/* Prepare READ_16 command */
clear_scsi_pt_obj(ptp);
set_scsi_pt_cdb(ptp, r16CmdBlk, sizeof(r16CmdBlk));
set_scsi_pt_sense(ptp, sense_buffer, sizeof(sense_buffer));
set_scsi_pt_data_in(ptp, lb, READ16_REPLY_LEN);
res = do_scsi_pt(ptp, sg_fd, 20 /* secs timeout */, 1);
if (res) {
{
lock_guard<mutex> lg(console_mutex);
fprintf(stderr, "READ_16 do_scsi_pt() submission error\n");
res = pt_err(res);
}
goto err;
}
cat = get_scsi_pt_result_category(ptp);
if (SCSI_PT_RESULT_GOOD != cat) {
{
lock_guard<mutex> lg(console_mutex);
fprintf(stderr, "READ_16 do_scsi_pt() category problem\n");
res = pt_cat_no_good(cat, ptp, sense_buffer);
}
goto err;
}
u = (lb[0] << 24) + (lb[1] << 16) + (lb[2] << 8) + lb[3];
// Assuming u starts test as even (probably 0), expect it to stay even
if (0 == k)
odd = (1 == (u % 2));
++u;
lb[0] = (u >> 24) & 0xff;
lb[1] = (u >> 16) & 0xff;
lb[2] = (u >> 8) & 0xff;
lb[3] = u & 0xff;
if (wait_ms > 0) /* allow daylight for bad things ... */
this_thread::sleep_for(milliseconds{wait_ms});
else if (0 == wait_ms)
this_thread::yield(); // thread yield
else if (-2 == wait_ms)
sleep(0); // process yield ??
/* Prepare WRITE_16 command */
clear_scsi_pt_obj(ptp);
set_scsi_pt_cdb(ptp, w16CmdBlk, sizeof(w16CmdBlk));
set_scsi_pt_sense(ptp, sense_buffer, sizeof(sense_buffer));
set_scsi_pt_data_out(ptp, lb, WRITE16_REPLY_LEN);
res = do_scsi_pt(ptp, sg_fd, 20 /* secs timeout */, 1);
if (res) {
{
lock_guard<mutex> lg(console_mutex);
fprintf(stderr, "WRITE_16 do_scsi_pt() submission error\n");
res = pt_err(res);
}
goto err;
}
cat = get_scsi_pt_result_category(ptp);
if (SCSI_PT_RESULT_GOOD != cat) {
{
lock_guard<mutex> lg(console_mutex);
fprintf(stderr, "WRITE_16 do_scsi_pt() category problem\n");
res = pt_cat_no_good(cat, ptp, sense_buffer);
}
goto err;
}
}
err:
if (ptp)
destruct_scsi_pt_obj(ptp);
scsi_pt_close_device(sg_fd);
return odd;
}
#define INQ_REPLY_LEN 96
#define INQ_CMD_LEN 6
/* Send INQUIRY and fetches response. If okay puts PRODUCT ID field
* in b (up to m_blen bytes). Does not use O_EXCL flag. Returns 0 on success,
* else -1 . */
static int
do_inquiry_prod_id(const char * dev_name, int block, int wait_ms,
unsigned int & ebusys, char * b, int b_mlen)
{
int sg_fd, res, cat;
struct sg_pt_base * ptp = NULL;
unsigned char inqCmdBlk [INQ_CMD_LEN] =
{0x12, 0, 0, 0, INQ_REPLY_LEN, 0};
unsigned char inqBuff[INQ_REPLY_LEN];
unsigned char sense_buffer[64];
char ebuff[EBUFF_SZ];
int open_flags = O_RDWR; /* since O_EXCL | O_RDONLY gives EPERM */
if (! block)
open_flags |= O_NONBLOCK;
while (((sg_fd = scsi_pt_open_flags(dev_name, open_flags, 0)) < 0) &&
(-EBUSY == sg_fd)) {
++ebusys;
if (wait_ms > 0)
this_thread::sleep_for(milliseconds{wait_ms});
else if (0 == wait_ms)
this_thread::yield(); // thread yield
else if (-2 == wait_ms)
sleep(0); // process yield ??
}
if (sg_fd < 0) {
snprintf(ebuff, EBUFF_SZ,
"do_inquiry_prod_id: error opening file: %s", dev_name);
perror(ebuff);
return -1;
}
/* Prepare INQUIRY command */
ptp = construct_scsi_pt_obj();
clear_scsi_pt_obj(ptp);
set_scsi_pt_cdb(ptp, inqCmdBlk, sizeof(inqCmdBlk));
set_scsi_pt_sense(ptp, sense_buffer, sizeof(sense_buffer));
set_scsi_pt_data_in(ptp, inqBuff, INQ_REPLY_LEN);
res = do_scsi_pt(ptp, sg_fd, 20 /* secs timeout */, 1);
if (res) {
{
lock_guard<mutex> lg(console_mutex);
fprintf(stderr, "INQUIRY do_scsi_pt() submission error\n");
res = pt_err(res);
}
goto err;
}
cat = get_scsi_pt_result_category(ptp);
if (SCSI_PT_RESULT_GOOD != cat) {
{
lock_guard<mutex> lg(console_mutex);
fprintf(stderr, "INQUIRY do_scsi_pt() category problem\n");
res = pt_cat_no_good(cat, ptp, sense_buffer);
}
goto err;
}
/* Good, so fetch Product ID from response, copy to 'b' */
if (b_mlen > 0) {
if (b_mlen > 16) {
memcpy(b, inqBuff + 16, 16);
b[16] = '\0';
} else {
memcpy(b, inqBuff + 16, b_mlen - 1);
b[b_mlen - 1] = '\0';
}
}
err:
if (ptp)
destruct_scsi_pt_obj(ptp);
close(sg_fd);
return 0;
}
static void
work_thread(const char * dev_name, unsigned int lba, int id, int block,
int excl, int num, int wait_ms)
{
unsigned int thr_odd_count = 0;
unsigned int thr_ebusy_count = 0;
int k, res;
{
lock_guard<mutex> lg(console_mutex);
cerr << "Enter work_thread id=" << id << " excl=" << excl << " block="
<< block << endl;
}
for (k = 0; k < num; ++k) {
res = do_rd_inc_wr_twice(dev_name, lba, block, excl, wait_ms,
thr_ebusy_count);
if (res < 0)
break;
if (res)
++thr_odd_count;
}
{
lock_guard<mutex> lg(console_mutex);
if (k < num)
cerr << "thread id=" << id << " FAILed at iteration: " << k <<
'\n';
else
cerr << "thread id=" << id << " normal exit" << '\n';
}
{
lock_guard<mutex> lg(odd_count_mutex);
odd_count += thr_odd_count;
ebusy_count += thr_ebusy_count;
}
}
int
main(int argc, char * argv[])
{
int k, res;
int block = 0;
int force = 0;
unsigned int lba = DEF_LBA;
int num_per_thread = DEF_NUM_PER_THREAD;
int num_threads = DEF_NUM_THREADS;
int wait_ms = DEF_WAIT_MS;
int exclude_o_excl = 0;
char * dev_name = NULL;
char b[64];
for (k = 1; k < argc; ++k) {
if (0 == memcmp("-b", argv[k], 2))
++block;
else if (0 == memcmp("-f", argv[k], 2))
++force;
else if (0 == memcmp("-h", argv[k], 2)) {
usage();
return 0;
} else if (0 == memcmp("-l", argv[k], 2)) {
++k;
if ((k < argc) && isdigit(*argv[k]))
lba = (unsigned int)atoi(argv[k]);
else
break;
} else if (0 == memcmp("-n", argv[k], 2)) {
++k;
if ((k < argc) && isdigit(*argv[k]))
num_per_thread = atoi(argv[k]);
else
break;
} else if (0 == memcmp("-t", argv[k], 2)) {
++k;
if ((k < argc) && isdigit(*argv[k]))
num_threads = atoi(argv[k]);
else
break;
} else if (0 == memcmp("-V", argv[k], 2)) {
printf("%s version: %s\n", util_name, version_str);
return 0;
} else if (0 == memcmp("-w", argv[k], 2)) {
++k;
if ((k < argc) && (isdigit(*argv[k]) || ('-' == *argv[k]))) {
if ('-' == *argv[k])
wait_ms = - atoi(argv[k] + 1);
else
wait_ms = atoi(argv[k]);
} else
break;
} else if (0 == memcmp("-x", argv[k], 2))
++exclude_o_excl;
else if (*argv[k] == '-') {
printf("Unrecognized switch: %s\n", argv[k]);
dev_name = NULL;
break;
}
else if (! dev_name)
dev_name = argv[k];
else {
printf("too many arguments\n");
dev_name = 0;
break;
}
}
if (0 == dev_name) {
usage();
return 1;
}
try {
if (! force) {
res = do_inquiry_prod_id(dev_name, block, wait_ms, ebusy_count,
b, sizeof(b));
if (res) {
fprintf(stderr, "INQUIRY failed on %s\n", dev_name);
return 1;
}
// For safety, since <lba> written to, only permit scsi_debug
// devices. Bypass this with '-f' option.
if (0 != memcmp("scsi_debug", b, 10)) {
fprintf(stderr, "Since this utility writes to LBA %d, only "
"devices with scsi_debug\nproduct ID accepted.\n",
lba);
return 2;
}
}
vector<thread *> vt;
for (k = 0; k < num_threads; ++k) {
int excl = ((0 == k) && exclude_o_excl) ? 0 : 1;
thread * tp = new thread {work_thread, dev_name, lba, k, block,
excl, num_per_thread, wait_ms};
vt.push_back(tp);
}
for (k = 0; k < (int)vt.size(); ++k)
vt[k]->join();
for (k = 0; k < (int)vt.size(); ++k)
delete vt[k];
cout << "Expecting odd count of 0, got " << odd_count << endl;
cout << "Number of EBUSYs: " << ebusy_count << endl;
}
catch(system_error& e) {
cerr << "got a system_error exception: " << e.what() << '\n';
auto ec = e.code();
cerr << "category: " << ec.category().name() << '\n';
cerr << "value: " << ec.value() << '\n';
cerr << "message: " << ec.message() << '\n';
cerr << "\nNote: if g++ may need '-pthread' or similar in "
"compile/link line" << '\n';
}
catch(...) {
cerr << "got another exception: " << '\n';
}
return 0;
}
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