sessreg.c

Bug Summary

File:	sessreg.c
Location:	line 286, column 7
Description:	Null pointer passed as an argument to a 'nonnull' parameter

Annotated Source Code

* Permission to use, copy, modify, distribute, and sell this software and its

* documentation for any purpose is hereby granted without fee, provided that

* the above copyright notice appear in all copies and that both that

* copyright notice and this permission notice appear in supporting

* documentation.

* The above copyright notice and this permission notice shall be included

* in all copies or substantial portions of the Software.

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

* IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR

* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

* OTHER DEALINGS IN THE SOFTWARE.

* Except as contained in this notice, the name of The Open Group shall

* not be used in advertising or otherwise to promote the sale, use or

* other dealings in this Software without prior written authorization

* from The Open Group.

* Permission is hereby granted, free of charge, to any person obtaining a

* copy of this software and associated documentation files (the "Software"),

* to deal in the Software without restriction, including without limitation

* the rights to use, copy, modify, merge, publish, distribute, sublicense,

* and/or sell copies of the Software, and to permit persons to whom the

* Software is furnished to do so, subject to the following conditions:

* The above copyright notice and this permission notice (including the next

* paragraph) shall be included in all copies or substantial portions of the

* Software.

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

* DEALINGS IN THE SOFTWARE.

* Author: Keith Packard, MIT X Consortium

* Lastlog support and dynamic utmp entry allocation

* by Andreas Stolcke <stolcke@icsi.berkeley.edu>

* sessreg

* simple wtmp/utmp frobber

* usage: sessreg [ -w <wtmp-file> ] [ -u <utmp-file> ]

* [ -l <line> ]

* [ -L <lastlog-file> ] / #ifdef USE_LASTLOG

* [ -h <host-name> ] / BSD only

* [ -s <slot-number> ] [ -x Xservers-file ] / BSD only

* [ -t <ttys-file> ] / BSD only

* [ -a ] [ -d ] user-name

* one of -a or -d must be specified

#include "sessreg.h"

#include <X11/Xos.h>

#include <X11/Xfuncs.h>

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

#ifdef USE_UTMP

static void set_utmp (struct utmp *u, char *line, char *user, char *host,

time_t date, int addp);

#endif

#ifdef USE_UTMPX

static void set_utmpx (struct utmpx *u, const char *line, const char *user,

const char *host, time_t date, int addp);

#endif

static int wflag, uflag, lflag;

static const char *wtmp_file, *utmp_file;

static char *line;

#ifdef USE_UTMPX

#ifdef HAVE_UPDWTMPX1

static const char *wtmpx_file = NULL((void*)0);

#endif

#ifdef HAVE_UTMPXNAME1

static const char *utmpx_file = NULL((void*)0);

100

#endif

101

#endif

102

static int utmp_none, wtmp_none;

103

104

* BSD specific variables. To make life much easier for Xstartup/Xreset

105

* maintainers, these arguments are accepted but ignored for sysV

106

107

static int hflag, xflag, tflag;

108

static char *host_name = NULL((void*)0);

109

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

110

static int sflag;

111

static int slot_number;

112

#endif

113

static char *xservers_file, *ttys_file;

114

static char *user_name;

115

static int aflag, dflag;

116

#ifdef USE_LASTLOG

117

static const char *llog_file;

118

static int llog_none, Lflag;

119

#endif

120

121

static char *program_name;

122

123

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

124

static int findslot (char *line_name, char *host_name, int addp, int slot);

125

static int Xslot (char *ttys_file, char *servers_file, char *tty_line,

126

char *host_name, int addp);

127

#endif

128

129

static int

130

usage (int x)

131

{

132

if (x) {

133

fprintf (stderrstderr, "%s: usage %s {-a -d} [-w wtmp-file] [-u utmp-file]", program_name, program_name);

134

#ifdef USE_LASTLOG

135

fprintf (stderrstderr, " [-L lastlog-file]");

136

#endif

137

fprintf (stderrstderr, "\n");

138

fprintf (stderrstderr, " [-t ttys-file] [-l line-name] [-h host-name]\n");

139

fprintf (stderrstderr, " [-s slot-number] [-x servers-file] user-name\n");

140

exit (1);

141

}

142

return x;

143

}

144

145

static char *

146

getstring (char ***avp, int *flagp)

147

{

148

char **a = *avp;

149

150

usage ((*flagp)++);

151

if (*++*a)

152

return *a;

153

++a;

154

usage (!*a);

155

*avp = a;

156

return *a;

157

}

158

159

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

160

static int

161

syserr (int x, const char *s)

162

{

163

if (x == -1) {

164

perror (s);

165

exit (1);

166

}

167

return x;

168

}

169

#endif

170

171

static int

172

sysnerr (int x, const char *s)

173

{

174

if (x == 0) {

175

perror (s);

176

exit (1);

177

}

178

return x;

179

}

180

181

int

182

main (int argc, char **argv)

183

{

184

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

185

int utmp;

186

#endif

187

#ifndef USE_UTMPX

188

int wtmp;

189

#endif

190

time_t current_time;

191

#ifdef USE_UTMP

192

struct utmp utmp_entry;

193

#endif

194

#ifdef USE_UTMPX

195

struct utmpx utmpx_entry;

196

#endif

197

198

program_name = argv[0];

199

while (*++argv && **argv == '-') {

1	Loop condition is false. Execution continues on line 245

200

switch (*++*argv) {

201

case 'w':

202

wtmp_file = getstring (&argv, &wflag);

203

if (!strcmp (wtmp_file, "none"))

204

wtmp_none = 1;

205

break;

206

case 'u':

207

utmp_file = getstring (&argv, &uflag);

208

if (!strcmp (utmp_file, "none"))

209

utmp_none = 1;

210

break;

211

#ifdef USE_LASTLOG

212

case 'L':

213

llog_file = getstring (&argv, &Lflag);

214

if (!strcmp (llog_file, "none"))

215

llog_none = 1;

216

break;

217

#endif

218

case 't':

219

ttys_file = getstring (&argv, &tflag);

220

break;

221

case 'l':

222

line = getstring (&argv, &lflag);

223

break;

224

case 'h':

225

host_name = getstring (&argv, &hflag);

226

break;

227

case 's':

228

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

229

slot_number = atoi (getstring (&argv, &sflag));

230

#endif

231

break;

232

case 'x':

233

xservers_file = getstring (&argv, &xflag);

234

break;

235

case 'a':

236

aflag++;

237

break;

238

case 'd':

239

dflag++;

240

break;

241

default:

242

usage (1);

243

}

244

}

245

usage (!(user_name = *argv++));

246

usage (*argv != NULL((void*)0));

247

248

* complain if neither aflag nor dflag are set,

249

* or if both are set.

250

251

usage (!(aflag ^ dflag));

252

usage (xflag && !lflag);

253

/* set up default file names */

254

if (!wflag) {

2	Assuming 'wflag' is not equal to 0

3	Taking false branch

255

wtmp_file = WTMP_FILE"/var/log/wtmp";

256

#if defined(USE_UTMPX) && defined(HAVE_UPDWTMPX1)

257

wtmpx_file = WTMPX_FILE"/var/log/wtmp";

258

#endif

259

}

260

#ifndef NO_UTMP

261

if (!uflag) {

4	Assuming 'uflag' is not equal to 0

5	Taking false branch

262

utmp_file = UTMP_FILE"/var/run/utmp";

263

#if defined(USE_UTMPX) && defined(HAVE_UTMPXNAME1)

264

utmpx_file = UTMPX_FILE"/var/run/utmp";

265

#endif

266

}

267

#else

268

utmp_none = 1;

269

#endif

270

#ifdef USE_LASTLOG

271

if (!Lflag)

6	Assuming 'Lflag' is not equal to 0

7	Taking false branch

272

llog_file = LLOG_FILE"/var/log/lastlog";

273

#endif

274

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

275

if (!tflag)

276

ttys_file = TTYS_FILE"/etc/ttys";

277

if (!sflag && !utmp_none) {

278

if (xflag)

279

sysnerr (slot_number = Xslot (ttys_file, xservers_file, line, host_name, aflag), "Xslot");

280

else

281

sysnerr (slot_number = ttyslot (), "ttyslot");

282

}

283

#endif

284

if (!lflag) {

8	Assuming 'lflag' is 0

9	Taking true branch

285

sysnerr ((line = ttyname (0)) != NULL((void*)0), "ttyname");

286

if (strncmp(line, "/dev/", 5) == 0)

10	Null pointer passed as an argument to a 'nonnull' parameter

287

line += 5;

288

}

289

time (&current_time);

290

#ifdef USE_UTMP

291

set_utmp (&utmp_entry, line, user_name, host_name, current_time, aflag);

292

#endif

293

294

#ifdef USE_UTMPX

295

/* need to set utmpxname() before calling set_utmpx() for

296

UtmpxIdOpen to work */

297

# ifdef HAVE_UTMPXNAME1

298

if (utmpx_file != NULL((void*)0)) {

299

utmpxname (utmpx_file);

300

}

301

# endif

302

set_utmpx (&utmpx_entry, line, user_name,

303

host_name, current_time, aflag);

304

#endif

305

306

if (!utmp_none) {

307

#ifdef USE_UTMPX

308

# ifdef HAVE_UTMPXNAME1

309

if (utmpx_file != NULL((void*)0))

310

# endif

311

{

312

setutxent ();

313

(void) getutxid (&utmpx_entry);

314

pututxline (&utmpx_entry);

315

endutxent ();

316

}

317

#endif

318

#ifdef USE_UTMP

319

# ifdef HAVE_PUTUTLINE1

320

utmpname (utmp_file);

321

setutent ();

322

(void) getutid (&utmp_entry);

323

pututline (&utmp_entry);

324

endutent ();

325

# else

326

utmp = open (utmp_file, O_RDWR02);

327

if (utmp != -1) {

328

syserr ((int) lseek (utmp, (long) slot_number * sizeof (struct utmp), 0), "lseek");

329

sysnerr (write (utmp, (char *) &utmp_entry, sizeof (utmp_entry))

330

== sizeof (utmp_entry), "write utmp entry");

331

close (utmp);

332

}

333

# endif

334

#endif /* USE_UTMP */

335

}

336

if (!wtmp_none) {

337

#ifdef USE_UTMPX

338

# ifdef HAVE_UPDWTMPX1

339

if (wtmpx_file != NULL((void*)0)) {

340

updwtmpx(wtmpx_file, &utmpx_entry);

341

}

342

# endif

343

#else

344

wtmp = open (wtmp_file, O_WRONLY01|O_APPEND02000);

345

if (wtmp != -1) {

346

sysnerr (write (wtmp, (char *) &utmp_entry, sizeof (utmp_entry))

347

== sizeof (utmp_entry), "write wtmp entry");

348

close (wtmp);

349

}

350

#endif

351

}

352

#ifdef USE_LASTLOG

353

if (aflag && !llog_none) {

354

int llog;

355

struct passwd *pwd = getpwnam(user_name);

356

357

sysnerr( pwd != NULL((void*)0), "get user id");

358

llog = open (llog_file, O_RDWR02);

359

360

if (llog != -1) {

361

struct lastlog ll;

362

363

sysnerr (lseek(llog, (long) pwd->pw_uid*sizeof(ll), 0)

364

!= -1, "seeking lastlog entry");

365

memset(&ll, 0, sizeof(ll));

366

ll.ll_time = current_time;

367

if (line)

368

(void) strncpy (ll.ll_line, line, sizeof (ll.ll_line));

369

if (host_name)

370

(void) strncpy (ll.ll_host, host_name, sizeof (ll.ll_host));

371

372

sysnerr (write (llog, (char *) &ll, sizeof (ll))

373

== sizeof (ll), "write lastlog entry");

374

close (llog);

375

}

376

}

377

#endif

378

return 0;

379

}

380

381

382

* fill in the appropriate records of the utmp entry

383

384

385

#ifdef USE_UTMP

386

static void

387

set_utmp (struct utmp *u, char *line, char *user, char *host, time_t date, int addp)

388

{

389

memset (u, 0, sizeof (*u));

390

if (line)

391

(void) strncpy (u->ut_line, line, sizeof (u->ut_line));

392

else

393

memset (u->ut_line, 0, sizeof (u->ut_line));

394

if (addp && user)

395

(void) strncpy (u->ut_nameut_user, user, sizeof (u->ut_nameut_user));

396

else

397

memset (u->ut_nameut_user, 0, sizeof (u->ut_nameut_user));

398

#ifdef HAVE_STRUCT_UTMP_UT_ID1

399

if (line) {

400

int i;

401

402

* this is a bit crufty, but

403

* follows the apparent conventions in

404

* the ttys file. ut_id is only 4 bytes

405

* long, and the last 4 bytes of the line

406

* name are written into it, left justified.

407

408

i = strlen (line);

409

if (i >= sizeof (u->ut_id))

410

i -= sizeof (u->ut_id);

411

else

412

i = 0;

413

(void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));

414

} else

415

memset (u->ut_id, 0, sizeof (u->ut_id));

416

#endif

417

#ifdef HAVE_STRUCT_UTMP_UT_PID1

418

if (addp)

419

u->ut_pid = getppid ();

420

else

421

u->ut_pid = 0;

422

#endif

423

#ifdef HAVE_STRUCT_UTMP_UT_TYPE1

424

if (addp)

425

u->ut_type = USER_PROCESS7;

426

else

427

u->ut_type = DEAD_PROCESS8;

428

#endif

429

#ifdef HAVE_STRUCT_UTMP_UT_HOST1

430

if (addp && host)

431

(void) strncpy (u->ut_host, host, sizeof (u->ut_host));

432

else

433

memset (u->ut_host, 0, sizeof (u->ut_host));

434

#endif

435

u->ut_timeut_tv.tv_sec = date;

436

}

437

#endif /* USE_UTMP */

438

439

#ifdef USE_UTMPX

440

static int

441

UtmpxIdOpen( char *utmpId )

442

{

443

struct utmpx *u; /* pointer to entry in utmp file */

444

int status = 1; /* return code */

445

446

setutxent();

447

448

while ( (u = getutxent()) != NULL((void*)0) ) {

449

450

if ( (strncmp(u->ut_id, utmpId, 4) == 0 ) &&

451

u->ut_type != DEAD_PROCESS8 ) {

452

453

status = 0;

454

break;

455

}

456

}

457

458

endutxent();

459

return (status);

460

}

461

462

static void

463

set_utmpx (struct utmpx *u, const char *line, const char *user,

464

const char *host, time_t date, int addp)

465

{

466

static const char letters[] =

467

"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

468

469

if (line)

470

{

471

if(strcmp(line, ":0") == 0)

472

(void) strcpy(u->ut_line, "console");

473

else

474

(void) strncpy (u->ut_line, line, sizeof (u->ut_line));

475

476

strncpy(u->ut_host, line, sizeof(u->ut_host));

477

#ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN

478

u->ut_syslen = strlen(line);

479

#endif

480

}

481

else

482

memset (u->ut_line, 0, sizeof (u->ut_line));

483

if (addp && user)

484

(void) strncpy (u->ut_user, user, sizeof (u->ut_user));

485

else

486

memset (u->ut_user, 0, sizeof (u->ut_user));

487

488

if (line) {

489

int i;

490

491

* this is a bit crufty, but

492

* follows the apparent conventions in

493

* the ttys file. ut_id is only 4 bytes

494

* long, and the last 4 bytes of the line

495

* name are written into it, left justified.

496

497

i = strlen (line);

498

if (i >= sizeof (u->ut_id))

499

i -= sizeof (u->ut_id);

500

else

501

i = 0;

502

(void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));

503

504

/* make sure there is no entry using identical ut_id */

505

if (!UtmpxIdOpen(u->ut_id) && addp) {

506

int limit = sizeof(letters) - 1;

507

int t = 0;

508

509

u->ut_id[1] = line[i];

510

u->ut_id[2] = line[i+1];

511

u->ut_id[3] = line[i+2];

512

do {

513

u->ut_id[0] = letters[t];

514

t++;

515

} while (!UtmpxIdOpen(u->ut_id) && (t < limit));

516

}

517

if (!addp && strstr(line, ":") != NULL((void*)0)) {

518

struct utmpx *tmpu;

519

520

while ( (tmpu = getutxent()) != NULL((void*)0) ) {

521

if ( (strcmp(tmpu->ut_host, line) == 0 ) &&

522

tmpu->ut_type != DEAD_PROCESS8 ) {

523

strncpy(u->ut_id, tmpu->ut_id,

524

sizeof(u->ut_id));

525

break;

526

}

527

}

528

endutxent();

529

}

530

} else

531

memset (u->ut_id, 0, sizeof (u->ut_id));

532

533

if (addp) {

534

u->ut_pid = getppid ();

535

u->ut_type = USER_PROCESS7;

536

} else {

537

u->ut_pid = 0;

538

u->ut_type = DEAD_PROCESS8;

539

}

540

u->ut_tv.tv_sec = date;

541

u->ut_tv.tv_usec = 0;

542

}

543

#endif /* USE_UTMPX */

544

545

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

546

547

* compute the slot-number for an X display. This is computed

548

* by counting the lines in /etc/ttys and adding the line-number

549

* that the display appears on in Xservers. This is a poor

550

* design, but is limited by the non-existant interface to utmp.

551

* If host_name is non-NULL, assume it contains the display name,

552

* otherwise use the tty_line argument (i.e., the tty name).

553

554

555

static int

556

Xslot (char *ttys_file, char *servers_file, char *tty_line, char *host_name,

557

int addp)

558

{

559

FILE *ttys, *servers;

560

int c;

561

int slot = 1;

562

int column0 = 1;

563

char servers_line[1024];

564

char disp_name[512];

565

int len;

566

char *pos;

567

568

/* remove screen number from the display name */

569

memset(disp_name, 0, sizeof(disp_name));

570

strncpy(disp_name, host_name ? host_name : tty_line, sizeof(disp_name)-1);

571

pos = strrchr(disp_name, ':');

572

if (pos) {

573

pos = strchr(pos, '.');

574

if (pos)

575

*pos = '\0';

576

}

577

sysnerr ((int)(long)(ttys = fopen (ttys_file, "r")), ttys_file);

578

while ((c = getc (ttys)_IO_getc (ttys)) != EOF(-1))

579

if (c == '\n') {

580

++slot;

581

column0 = 1;

582

} else

583

column0 = 0;

584

if (!column0)

585

++slot;

586

(void) fclose (ttys);

587

sysnerr ((int)(long)(servers = fopen (servers_file, "r")), servers_file);

588

589

len = strlen (disp_name);

590

column0 = 1;

591

while (fgets (servers_line, sizeof (servers_line), servers)) {

592

if (column0 && *servers_line != '#') {

593

if (!strncmp (disp_name, servers_line, len) &&

594

(servers_line[len] == ' ' ||

595

servers_line[len] == '\t'))

596

return slot;

597

++slot;

598

}

599

if (servers_line[strlen(servers_line)-1] != '\n')

600

column0 = 0;

601

else

602

column0 = 1;

603

}

604

605

* display not found in Xservers file - allocate utmp entry dinamically

606

607

return findslot (tty_line, host_name, addp, slot);

608

}

609

610

611

* find a free utmp slot for the X display. This allocates a new entry

612

* past the regular tty entries if necessary, reusing existing entries

613

* (identified by (line,hostname)) if possible.

614

615

static int

616

findslot (char *line_name, char *host_name, int addp, int slot)

617

{

618

int utmp;

619

struct utmp entry;

620

int found = 0;

621

int freeslot = -1;

622

623

syserr(utmp = open (utmp_file, O_RDONLY00), "open utmp");

624

625

626

* first, try to locate a previous entry for this display

627

* also record location of a free slots in case we need a new one

628

629

syserr ((int) lseek (utmp, (long) slot * sizeof (struct utmp), 0), "lseek");

630

631

if (!host_name)

632

host_name = "";

633

634

while (read (utmp, (char *) &entry, sizeof (entry)) == sizeof (entry)) {

635

if (strncmp(entry.ut_line, line_name,

636

sizeof(entry.ut_line)) == 0

637

#ifdef HAVE_STRUCT_UTMP_UT_HOST1

638

639

strncmp(entry.ut_host, host_name,

640

sizeof(entry.ut_host)) == 0

641

#endif

642

) {

643

found = 1;

644

break;

645

}

646

if (freeslot < 0 && *entry.ut_nameut_user == '\0')

647

freeslot = slot;

648

++slot;

649

}

650

651

close (utmp);

652

653

if (found)

654

return slot;

655

else if (!addp)

656

return 0; /* trying to delete a non-existing entry */

657

else if (freeslot < 0)

658

return slot; /* first slot past current entries */

659

else

660

return freeslot;

661

}

662

#endif