- 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[MAXNAMLEN + 1];
- char cfarg[SHSIZE];
- int resid;
-
- if ((ip = namei(uchar, 0, 1)) == 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 ((u.u_procp->p_flag&STRC) && access(ip, IREAD))
- 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_error = rdwri(UIO_READ, ip, (caddr_t)&u.u_exdata, sizeof (u.u_exdata),
- 0, 1, &resid);
- if (u.u_error)
- goto bad;
- u.u_count = resid;
-#ifndef lint
- 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;
- }
-#endif
- 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_dent.d_name, (caddr_t)cfname,
- (unsigned)(u.u_dent.d_namlen + 1));
- indir = 1;
- iput(ip);
- ip = namei(schar, 0, 1);
- if (ip == NULL)
- return;
- goto again;
- }