- register nc;
- register char *cp;
- register struct buf *bp;
- register struct execa *uap;
- int na, ne, ucp, ap, c;
- int indir, uid, gid;
- char *sharg;
- struct inode *ip;
- swblk_t bno;
- char cfname[DIRSIZ];
- char cfarg[SHSIZE];
-
- if ((ip = namei(uchar, 0)) == NULL)
- return;
-
- bno = 0;
- bp = 0;
- indir = 0;
- uid = u.u_uid;
- gid = u.u_gid;
-
- if (ip->i_mode & ISUID)
- uid = ip->i_uid;
- if (ip->i_mode & ISGID)
- gid = ip->i_gid;
-
- again:
- if(access(ip, IEXEC))
- goto bad;
- if((ip->i_mode & IFMT) != IFREG ||
- (ip->i_mode & (IEXEC|(IEXEC>>3)|(IEXEC>>6))) == 0) {
- u.u_error = EACCES;
- goto bad;
- }
-
- /*
- * Read in first few bytes of file for segment sizes, ux_mag:
- * 407 = plain executable
- * 410 = RO text
- * 413 = demand paged RO text
- * Also an ASCII line beginning with #! is
- * the file name of a ``shell'' and arguments may be prepended
- * to the argument list if given here.
- *
- * SHELL NAMES ARE LIMITED IN LENGTH.
- *
- * ONLY ONE ARGUMENT MAY BE PASSED TO THE SHELL FROM
- * THE ASCII LINE.
- */
- u.u_base = (caddr_t)&u.u_exdata;
- u.u_count = sizeof(u.u_exdata);
- u.u_offset = 0;
- u.u_segflg = 1;
- readi(ip);
- u.u_segflg = 0;
- if(u.u_error)
- goto bad;
- if (u.u_count > sizeof(u.u_exdata) - sizeof(u.u_exdata.Ux_A)
- && u.u_exdata.ux_shell[0] != '#') {
- u.u_error = ENOEXEC;
- goto bad;
- }
- switch (u.u_exdata.ux_mag) {
-
- case 0407:
- u.u_exdata.ux_dsize += u.u_exdata.ux_tsize;
- u.u_exdata.ux_tsize = 0;
- break;
-
- case 0413:
- case 0410:
- if (u.u_exdata.ux_tsize == 0) {
- u.u_error = ENOEXEC;
- goto bad;
- }
- break;
-
- default:
- if (u.u_exdata.ux_shell[0] != '#' ||
- u.u_exdata.ux_shell[1] != '!' ||
- indir) {
- u.u_error = ENOEXEC;
- goto bad;
- }
- cp = &u.u_exdata.ux_shell[2]; /* skip "#!" */
- while (cp < &u.u_exdata.ux_shell[SHSIZE]) {
- if (*cp == '\t')
- *cp = ' ';
- else if (*cp == '\n') {
- *cp = '\0';
- break;
- }
- cp++;
- }
- if (*cp != '\0') {
- u.u_error = ENOEXEC;
- goto bad;
- }
- cp = &u.u_exdata.ux_shell[2];
- while (*cp == ' ')
- cp++;
- u.u_dirp = cp;
- while (*cp && *cp != ' ')
- cp++;
- sharg = NULL;
- if (*cp) {
- *cp++ = '\0';
- while (*cp == ' ')
- cp++;
- if (*cp) {
- bcopy((caddr_t)cp, (caddr_t)cfarg, SHSIZE);
- sharg = cfarg;
- }
- }
- bcopy((caddr_t)u.u_dbuf, (caddr_t)cfname, DIRSIZ);
- indir = 1;
- iput(ip);
- ip = namei(schar, 0);
- if (ip == NULL)
- return;
- goto again;
- }
-
- /*
- * Collect arguments on "file" in swap space.
- */
- na = 0;
- ne = 0;
- nc = 0;
- uap = (struct execa *)u.u_ap;
- if ((bno = malloc(argmap, ctod(clrnd((int) btoc(NCARGS))))) == 0) {
- swkill(u.u_procp, "exece");
- goto bad;
- }
- if (bno % CLSIZE)
- panic("execa malloc");
- if (uap->argp) for (;;) {
- ap = NULL;
- if (na == 1 && indir) {
- if (sharg == NULL)
- ap = (int)uap->fname;
- } else if (na == 2 && indir && sharg != NULL)
- ap = (int)uap->fname;
- else if (uap->argp) {
- ap = fuword((caddr_t)uap->argp);
- uap->argp++;
- }
- if (ap==NULL && uap->envp) {
- uap->argp = NULL;
- if ((ap = fuword((caddr_t)uap->envp)) == NULL)
- break;
- uap->envp++;
- ne++;
- }
- if (ap==NULL)
- break;
- na++;
- if(ap == -1)
- u.u_error = EFAULT;
- do {
- if (nc >= NCARGS-1)
- u.u_error = E2BIG;
- if (indir && na == 2 && sharg != NULL)
- c = *sharg++ & 0377;
- else if ((c = fubyte((caddr_t)ap++)) < 0)
- u.u_error = EFAULT;
- if (u.u_error) {
- if (bp)
- brelse(bp);
- bp = 0;
- goto badarg;
- }
- if ((nc&BMASK) == 0) {
- if (bp)
- bdwrite(bp);
- bp = getblk(argdev,
- (daddr_t)(dbtofsb(bno)+(nc>>BSHIFT)));
- cp = bp->b_un.b_addr;
- }
- nc++;
- *cp++ = c;
- } while (c>0);
- }
- if (bp)
- bdwrite(bp);
- bp = 0;
- nc = (nc + NBPW-1) & ~(NBPW-1);
- if (indir)
- bcopy((caddr_t)cfname, (caddr_t)u.u_dbuf, DIRSIZ);
- getxfile(ip, nc + (na+4)*NBPW, uid, gid);
- if (u.u_error) {
-badarg:
- for (c = 0; c < nc; c += BSIZE)
- if (bp = baddr(argdev, dbtofsb(bno)+(c>>BSHIFT))) {
- bp->b_flags |= B_AGE; /* throw away */
- bp->b_flags &= ~B_DELWRI; /* cancel io */
- brelse(bp);
- bp = 0;
- }
- goto bad;
- }