4.3BSD - /usr/src/sys/sys/kern_exec.c

   1: /*
   2:  * Copyright (c) 1982, 1986 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  *
   6:  *	@(#)kern_exec.c	7.1 (Berkeley) 6/5/86
   7:  */
   8: 
   9: #include "../machine/reg.h"
  10: #include "../machine/pte.h"
  11: #include "../machine/psl.h"
  12: 
  13: #include "param.h"
  14: #include "systm.h"
  15: #include "map.h"
  16: #include "dir.h"
  17: #include "user.h"
  18: #include "kernel.h"
  19: #include "proc.h"
  20: #include "buf.h"
  21: #include "inode.h"
  22: #include "seg.h"
  23: #include "vm.h"
  24: #include "text.h"
  25: #include "file.h"
  26: #include "uio.h"
  27: #include "acct.h"
  28: #include "exec.h"
  29: 
  30: #ifdef vax
  31: #include "../vax/mtpr.h"
  32: #endif
  33: 
  34: /*
  35:  * exec system call, with and without environments.
  36:  */
  37: struct execa {
  38:     char    *fname;
  39:     char    **argp;
  40:     char    **envp;
  41: };
  42: 
  43: execv()
  44: {
  45:     ((struct execa *)u.u_ap)->envp = NULL;
  46:     execve();
  47: }
  48: 
  49: execve()
  50: {
  51:     register nc;
  52:     register char *cp;
  53:     register struct buf *bp;
  54:     register struct execa *uap;
  55:     int na, ne, ucp, ap, cc;
  56:     unsigned len;
  57:     int indir, uid, gid;
  58:     char *sharg;
  59:     struct inode *ip;
  60:     swblk_t bno;
  61:     char cfname[MAXCOMLEN + 1];
  62: #define SHSIZE  32
  63:     char cfarg[SHSIZE];
  64:     union {
  65:         char    ex_shell[SHSIZE];   /* #! and name of interpreter */
  66:         struct  exec ex_exec;
  67:     } exdata;
  68:     register struct nameidata *ndp = &u.u_nd;
  69:     int resid, error;
  70: 
  71:     ndp->ni_nameiop = LOOKUP | FOLLOW;
  72:     ndp->ni_segflg = UIO_USERSPACE;
  73:     ndp->ni_dirp = ((struct execa *)u.u_ap)->fname;
  74:     if ((ip = namei(ndp)) == NULL)
  75:         return;
  76:     bno = 0;
  77:     bp = 0;
  78:     indir = 0;
  79:     uid = u.u_uid;
  80:     gid = u.u_gid;
  81:     if (ip->i_mode & ISUID)
  82:         uid = ip->i_uid;
  83:     if (ip->i_mode & ISGID)
  84:         gid = ip->i_gid;
  85: 
  86:   again:
  87:     if (access(ip, IEXEC))
  88:         goto bad;
  89:     if ((u.u_procp->p_flag&STRC) && access(ip, IREAD))
  90:         goto bad;
  91:     if ((ip->i_mode & IFMT) != IFREG ||
  92:        (ip->i_mode & (IEXEC|(IEXEC>>3)|(IEXEC>>6))) == 0) {
  93:         u.u_error = EACCES;
  94:         goto bad;
  95:     }
  96: 
  97:     /*
  98: 	 * Read in first few bytes of file for segment sizes, magic number:
  99: 	 *	407 = plain executable
 100: 	 *	410 = RO text
 101: 	 *	413 = demand paged RO text
 102: 	 * Also an ASCII line beginning with #! is
 103: 	 * the file name of a ``shell'' and arguments may be prepended
 104: 	 * to the argument list if given here.
 105: 	 *
 106: 	 * SHELL NAMES ARE LIMITED IN LENGTH.
 107: 	 *
 108: 	 * ONLY ONE ARGUMENT MAY BE PASSED TO THE SHELL FROM
 109: 	 * THE ASCII LINE.
 110: 	 */
 111:     exdata.ex_shell[0] = '\0';  /* for zero length files */
 112:     u.u_error = rdwri(UIO_READ, ip, (caddr_t)&exdata, sizeof (exdata),
 113:         (off_t)0, 1, &resid);
 114:     if (u.u_error)
 115:         goto bad;
 116: #ifndef lint
 117:     if (resid > sizeof(exdata) - sizeof(exdata.ex_exec) &&
 118:         exdata.ex_shell[0] != '#') {
 119:         u.u_error = ENOEXEC;
 120:         goto bad;
 121:     }
 122: #endif
 123:     switch ((int)exdata.ex_exec.a_magic) {
 124: 
 125:     case 0407:
 126:         exdata.ex_exec.a_data += exdata.ex_exec.a_text;
 127:         exdata.ex_exec.a_text = 0;
 128:         break;
 129: 
 130:     case 0413:
 131:     case 0410:
 132:         if (exdata.ex_exec.a_text == 0) {
 133:             u.u_error = ENOEXEC;
 134:             goto bad;
 135:         }
 136:         break;
 137: 
 138:     default:
 139:         if (exdata.ex_shell[0] != '#' ||
 140:             exdata.ex_shell[1] != '!' ||
 141:             indir) {
 142:             u.u_error = ENOEXEC;
 143:             goto bad;
 144:         }
 145:         cp = &exdata.ex_shell[2];       /* skip "#!" */
 146:         while (cp < &exdata.ex_shell[SHSIZE]) {
 147:             if (*cp == '\t')
 148:                 *cp = ' ';
 149:             else if (*cp == '\n') {
 150:                 *cp = '\0';
 151:                 break;
 152:             }
 153:             cp++;
 154:         }
 155:         if (*cp != '\0') {
 156:             u.u_error = ENOEXEC;
 157:             goto bad;
 158:         }
 159:         cp = &exdata.ex_shell[2];
 160:         while (*cp == ' ')
 161:             cp++;
 162:         ndp->ni_dirp = cp;
 163:         while (*cp && *cp != ' ')
 164:             cp++;
 165:         cfarg[0] = '\0';
 166:         if (*cp) {
 167:             *cp++ = '\0';
 168:             while (*cp == ' ')
 169:                 cp++;
 170:             if (*cp)
 171:                 bcopy((caddr_t)cp, (caddr_t)cfarg, SHSIZE);
 172:         }
 173:         indir = 1;
 174:         iput(ip);
 175:         ndp->ni_nameiop = LOOKUP | FOLLOW;
 176:         ndp->ni_segflg = UIO_SYSSPACE;
 177:         ip = namei(ndp);
 178:         if (ip == NULL)
 179:             return;
 180:         bcopy((caddr_t)ndp->ni_dent.d_name, (caddr_t)cfname,
 181:             MAXCOMLEN);
 182:         cfname[MAXCOMLEN] = '\0';
 183:         goto again;
 184:     }
 185: 
 186:     /*
 187: 	 * Collect arguments on "file" in swap space.
 188: 	 */
 189:     na = 0;
 190:     ne = 0;
 191:     nc = 0;
 192:     cc = 0;
 193:     uap = (struct execa *)u.u_ap;
 194:     bno = rmalloc(argmap, (long)ctod(clrnd((int)btoc(NCARGS))));
 195:     if (bno == 0) {
 196:         swkill(u.u_procp, "exec: no swap space");
 197:         goto bad;
 198:     }
 199:     if (bno % CLSIZE)
 200:         panic("execa rmalloc");
 201:     /*
 202: 	 * Copy arguments into file in argdev area.
 203: 	 */
 204:     if (uap->argp) for (;;) {
 205:         ap = NULL;
 206:         sharg = NULL;
 207:         if (indir && na == 0) {
 208:             sharg = cfname;
 209:             ap = (int)sharg;
 210:             uap->argp++;        /* ignore argv[0] */
 211:         } else if (indir && (na == 1 && cfarg[0])) {
 212:             sharg = cfarg;
 213:             ap = (int)sharg;
 214:         } else if (indir && (na == 1 || na == 2 && cfarg[0]))
 215:             ap = (int)uap->fname;
 216:         else if (uap->argp) {
 217:             ap = fuword((caddr_t)uap->argp);
 218:             uap->argp++;
 219:         }
 220:         if (ap == NULL && uap->envp) {
 221:             uap->argp = NULL;
 222:             if ((ap = fuword((caddr_t)uap->envp)) != NULL)
 223:                 uap->envp++, ne++;
 224:         }
 225:         if (ap == NULL)
 226:             break;
 227:         na++;
 228:         if (ap == -1) {
 229:             u.u_error = EFAULT;
 230:             break;
 231:         }
 232:         do {
 233:             if (cc <= 0) {
 234:                 /*
 235: 				 * We depend on NCARGS being a multiple of
 236: 				 * CLSIZE*NBPG.  This way we need only check
 237: 				 * overflow before each buffer allocation.
 238: 				 */
 239:                 if (nc >= NCARGS-1) {
 240:                     error = E2BIG;
 241:                     break;
 242:                 }
 243:                 if (bp)
 244:                     bdwrite(bp);
 245:                 cc = CLSIZE*NBPG;
 246:                 bp = getblk(argdev, bno + ctod(nc/NBPG), cc);
 247:                 cp = bp->b_un.b_addr;
 248:             }
 249:             if (sharg) {
 250:                 error = copystr(sharg, cp, (unsigned)cc, &len);
 251:                 sharg += len;
 252:             } else {
 253:                 error = copyinstr((caddr_t)ap, cp, (unsigned)cc,
 254:                     &len);
 255:                 ap += len;
 256:             }
 257:             cp += len;
 258:             nc += len;
 259:             cc -= len;
 260:         } while (error == ENOENT);
 261:         if (error) {
 262:             u.u_error = error;
 263:             if (bp)
 264:                 brelse(bp);
 265:             bp = 0;
 266:             goto badarg;
 267:         }
 268:     }
 269:     if (bp)
 270:         bdwrite(bp);
 271:     bp = 0;
 272:     nc = (nc + NBPW-1) & ~(NBPW-1);
 273:     getxfile(ip, &exdata.ex_exec, nc + (na+4)*NBPW, uid, gid);
 274:     if (u.u_error) {
 275: badarg:
 276:         for (cc = 0; cc < nc; cc += CLSIZE*NBPG) {
 277:             bp = baddr(argdev, bno + ctod(cc/NBPG), CLSIZE*NBPG);
 278:             if (bp) {
 279:                 bp->b_flags |= B_AGE;       /* throw away */
 280:                 bp->b_flags &= ~B_DELWRI;   /* cancel io */
 281:                 brelse(bp);
 282:                 bp = 0;
 283:             }
 284:         }
 285:         goto bad;
 286:     }
 287:     iput(ip);
 288:     ip = NULL;
 289: 
 290:     /*
 291: 	 * Copy back arglist.
 292: 	 */
 293:     ucp = USRSTACK - nc - NBPW;
 294:     ap = ucp - na*NBPW - 3*NBPW;
 295:     u.u_ar0[SP] = ap;
 296:     (void) suword((caddr_t)ap, na-ne);
 297:     nc = 0;
 298:     cc = 0;
 299:     for (;;) {
 300:         ap += NBPW;
 301:         if (na == ne) {
 302:             (void) suword((caddr_t)ap, 0);
 303:             ap += NBPW;
 304:         }
 305:         if (--na < 0)
 306:             break;
 307:         (void) suword((caddr_t)ap, ucp);
 308:         do {
 309:             if (cc <= 0) {
 310:                 if (bp)
 311:                     brelse(bp);
 312:                 cc = CLSIZE*NBPG;
 313:                 bp = bread(argdev, bno + ctod(nc / NBPG), cc);
 314:                 bp->b_flags |= B_AGE;       /* throw away */
 315:                 bp->b_flags &= ~B_DELWRI;   /* cancel io */
 316:                 cp = bp->b_un.b_addr;
 317:             }
 318:             error = copyoutstr(cp, (caddr_t)ucp, (unsigned)cc,
 319:                 &len);
 320:             ucp += len;
 321:             cp += len;
 322:             nc += len;
 323:             cc -= len;
 324:         } while (error == ENOENT);
 325:         if (error == EFAULT)
 326:             panic("exec: EFAULT");
 327:     }
 328:     (void) suword((caddr_t)ap, 0);
 329: 
 330:     /*
 331: 	 * Reset caught signals.  Held signals
 332: 	 * remain held through p_sigmask.
 333: 	 */
 334:     while (u.u_procp->p_sigcatch) {
 335:         nc = ffs((long)u.u_procp->p_sigcatch);
 336:         u.u_procp->p_sigcatch &= ~sigmask(nc);
 337:         u.u_signal[nc] = SIG_DFL;
 338:     }
 339:     /*
 340: 	 * Reset stack state to the user stack.
 341: 	 * Clear set of signals caught on the signal stack.
 342: 	 */
 343:     u.u_onstack = 0;
 344:     u.u_sigsp = 0;
 345:     u.u_sigonstack = 0;
 346: 
 347:     for (nc = u.u_lastfile; nc >= 0; --nc) {
 348:         if (u.u_pofile[nc] & UF_EXCLOSE) {
 349:             closef(u.u_ofile[nc]);
 350:             u.u_ofile[nc] = NULL;
 351:             u.u_pofile[nc] = 0;
 352:         }
 353:         u.u_pofile[nc] &= ~UF_MAPPED;
 354:     }
 355:     while (u.u_lastfile >= 0 && u.u_ofile[u.u_lastfile] == NULL)
 356:         u.u_lastfile--;
 357:     setregs(exdata.ex_exec.a_entry);
 358:     /*
 359: 	 * Remember file name for accounting.
 360: 	 */
 361:     u.u_acflag &= ~AFORK;
 362:     if (indir)
 363:         bcopy((caddr_t)cfname, (caddr_t)u.u_comm, MAXCOMLEN);
 364:     else {
 365:         if (ndp->ni_dent.d_namlen > MAXCOMLEN)
 366:             ndp->ni_dent.d_namlen = MAXCOMLEN;
 367:         bcopy((caddr_t)ndp->ni_dent.d_name, (caddr_t)u.u_comm,
 368:             (unsigned)(ndp->ni_dent.d_namlen + 1));
 369:     }
 370: bad:
 371:     if (bp)
 372:         brelse(bp);
 373:     if (bno)
 374:         rmfree(argmap, (long)ctod(clrnd((int) btoc(NCARGS))), bno);
 375:     if (ip)
 376:         iput(ip);
 377: }
 378: 
 379: /*
 380:  * Read in and set up memory for executed file.
 381:  */
 382: getxfile(ip, ep, nargc, uid, gid)
 383:     register struct inode *ip;
 384:     register struct exec *ep;
 385:     int nargc, uid, gid;
 386: {
 387:     size_t ts, ds, ids, uds, ss;
 388:     int pagi;
 389: 
 390:     if (ep->a_magic == 0413)
 391:         pagi = SPAGI;
 392:     else
 393:         pagi = 0;
 394:     if (ip->i_text && (ip->i_text->x_flag & XTRC)) {
 395:         u.u_error = ETXTBSY;
 396:         goto bad;
 397:     }
 398:     if (ep->a_text != 0 && (ip->i_flag&ITEXT) == 0 &&
 399:         ip->i_count != 1) {
 400:         register struct file *fp;
 401: 
 402:         for (fp = file; fp < fileNFILE; fp++) {
 403:             if (fp->f_type == DTYPE_INODE &&
 404:                 fp->f_count > 0 &&
 405:                 (struct inode *)fp->f_data == ip &&
 406:                 (fp->f_flag&FWRITE)) {
 407:                 u.u_error = ETXTBSY;
 408:                 goto bad;
 409:             }
 410:         }
 411:     }
 412: 
 413:     /*
 414: 	 * Compute text and data sizes and make sure not too large.
 415: 	 * NB - Check data and bss separately as they may overflow
 416: 	 * when summed together.
 417: 	 */
 418:     ts = clrnd(btoc(ep->a_text));
 419:     ids = clrnd(btoc(ep->a_data));
 420:     uds = clrnd(btoc(ep->a_bss));
 421:     ds = clrnd(btoc(ep->a_data + ep->a_bss));
 422:     ss = clrnd(SSIZE + btoc(nargc));
 423:     if (chksize((unsigned)ts, (unsigned)ids, (unsigned)uds, (unsigned)ss))
 424:         goto bad;
 425: 
 426:     /*
 427: 	 * Make sure enough space to start process.
 428: 	 */
 429:     u.u_cdmap = zdmap;
 430:     u.u_csmap = zdmap;
 431:     if (swpexpand(ds, ss, &u.u_cdmap, &u.u_csmap) == NULL)
 432:         goto bad;
 433: 
 434:     /*
 435: 	 * At this point, committed to the new image!
 436: 	 * Release virtual memory resources of old process, and
 437: 	 * initialize the virtual memory of the new process.
 438: 	 * If we resulted from vfork(), instead wakeup our
 439: 	 * parent who will set SVFDONE when he has taken back
 440: 	 * our resources.
 441: 	 */
 442:     if ((u.u_procp->p_flag & SVFORK) == 0)
 443:         vrelvm();
 444:     else {
 445:         u.u_procp->p_flag &= ~SVFORK;
 446:         u.u_procp->p_flag |= SKEEP;
 447:         wakeup((caddr_t)u.u_procp);
 448:         while ((u.u_procp->p_flag & SVFDONE) == 0)
 449:             sleep((caddr_t)u.u_procp, PZERO - 1);
 450:         u.u_procp->p_flag &= ~(SVFDONE|SKEEP);
 451:     }
 452:     u.u_procp->p_flag &= ~(SPAGI|SSEQL|SUANOM|SOUSIG);
 453:     u.u_procp->p_flag |= pagi;
 454:     u.u_dmap = u.u_cdmap;
 455:     u.u_smap = u.u_csmap;
 456:     vgetvm(ts, ds, ss);
 457: 
 458:     if (pagi == 0)
 459:         u.u_error =
 460:             rdwri(UIO_READ, ip,
 461:             (char *)ctob(dptov(u.u_procp, 0)),
 462:             (int)ep->a_data,
 463:             (off_t)(sizeof (struct exec) + ep->a_text),
 464:             0, (int *)0);
 465:     xalloc(ip, ep, pagi);
 466:     if (pagi && u.u_procp->p_textp)
 467:         vinifod((struct fpte *)dptopte(u.u_procp, 0),
 468:             PG_FTEXT, u.u_procp->p_textp->x_iptr,
 469:             (long)(1 + ts/CLSIZE), (size_t)btoc(ep->a_data));
 470: 
 471: #ifdef vax
 472:     /* THIS SHOULD BE DONE AT A LOWER LEVEL, IF AT ALL */
 473:     mtpr(TBIA, 0);
 474: #endif
 475: 
 476:     if (u.u_error)
 477:         swkill(u.u_procp, "exec: I/O error mapping pages");
 478:     /*
 479: 	 * set SUID/SGID protections, if no tracing
 480: 	 */
 481:     if ((u.u_procp->p_flag&STRC)==0) {
 482:         u.u_uid = uid;
 483:         u.u_procp->p_uid = uid;
 484:         u.u_gid = gid;
 485:     } else
 486:         psignal(u.u_procp, SIGTRAP);
 487:     u.u_tsize = ts;
 488:     u.u_dsize = ds;
 489:     u.u_ssize = ss;
 490:     u.u_prof.pr_scale = 0;
 491: bad:
 492:     return;
 493: }

Defined functions

Defined struct's

Defined macros