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complete revised argument processing -- use copyoutstr to move
[unix-history] / usr / src / sys / kern / kern_exec.c
/* kern_exec.c 6.6 84/07/29 */
#include "../machine/reg.h"
#include "../machine/pte.h"
#include "../machine/psl.h"
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/map.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/kernel.h"
#include "../h/proc.h"
#include "../h/buf.h"
#include "../h/inode.h"
#include "../h/seg.h"
#include "../h/vm.h"
#include "../h/text.h"
#include "../h/file.h"
#include "../h/uio.h"
#include "../h/acct.h"
#include "../h/exec.h"
#ifdef vax
#include "../vax/mtpr.h"
#endif
/*
* exec system call, with and without environments.
*/
struct execa {
char *fname;
char **argp;
char **envp;
};
execv()
{
((struct execa *)u.u_ap)->envp = NULL;
execve();
}
execve()
{
register nc;
register char *cp;
register struct buf *bp;
register struct execa *uap;
int na, ne, ucp, ap, len, cc;
int indir, uid, gid;
char *sharg;
struct inode *ip;
swblk_t bno;
char cfname[MAXCOMLEN + 1];
#define SHSIZE 32
char cfarg[SHSIZE];
union {
char ex_shell[SHSIZE]; /* #! and name of interpreter */
struct exec ex_exec;
} exdata;
register struct nameidata *ndp = &u.u_nd;
int resid, error;
ndp->ni_nameiop = LOOKUP | FOLLOW;
ndp->ni_segflg = UIO_USERSPACE;
ndp->ni_dirp = ((struct execa *)u.u_ap)->fname;
if ((ip = namei(ndp)) == 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, magic number:
* 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.
*/
exdata.ex_shell[0] = '\0'; /* for zero length files */
u.u_error = rdwri(UIO_READ, ip, (caddr_t)&exdata, sizeof (exdata),
0, 1, &resid);
if (u.u_error)
goto bad;
#ifndef lint
if (resid > sizeof (exdata) - sizeof (exdata.ex_exec.a_magic) &&
exdata.ex_shell[0] != '#') {
u.u_error = ENOEXEC;
goto bad;
}
#endif
switch (exdata.ex_exec.a_magic) {
case 0407:
exdata.ex_exec.a_data += exdata.ex_exec.a_text;
exdata.ex_exec.a_text = 0;
break;
case 0413:
case 0410:
if (exdata.ex_exec.a_text == 0) {
u.u_error = ENOEXEC;
goto bad;
}
break;
default:
if (exdata.ex_shell[0] != '#' ||
exdata.ex_shell[1] != '!' ||
indir) {
u.u_error = ENOEXEC;
goto bad;
}
cp = &exdata.ex_shell[2]; /* skip "#!" */
while (cp < &exdata.ex_shell[SHSIZE]) {
if (*cp == '\t')
*cp = ' ';
else if (*cp == '\n') {
*cp = '\0';
break;
}
cp++;
}
if (*cp != '\0') {
u.u_error = ENOEXEC;
goto bad;
}
cp = &exdata.ex_shell[2];
while (*cp == ' ')
cp++;
ndp->ni_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;
}
}
if (ndp->ni_dent.d_namlen > MAXCOMLEN)
ndp->ni_dent.d_namlen = MAXCOMLEN;
bcopy((caddr_t)ndp->ni_dent.d_name, (caddr_t)cfname,
(unsigned)(ndp->ni_dent.d_namlen + 1));
cfname[MAXCOMLEN] = '\0';
indir = 1;
iput(ip);
ndp->ni_nameiop = LOOKUP | FOLLOW;
ndp->ni_segflg = UIO_SYSSPACE;
ip = namei(ndp);
if (ip == NULL)
return;
goto again;
}
/*
* Collect arguments on "file" in swap space.
*/
na = 0;
ne = 0;
nc = 0;
cc = 0;
uap = (struct execa *)u.u_ap;
bno = rmalloc(argmap, (long)ctod(clrnd((int)btoc(NCARGS))));
if (bno == 0) {
swkill(u.u_procp, "exece");
goto bad;
}
if (bno % CLSIZE)
panic("execa rmalloc");
/*
* Copy arguments into file in argdev area.
*/
if (uap->argp) for (;;) {
ap = NULL;
if (indir && (na == 1 || na == 2 && sharg))
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)
uap->envp++, ne++;
}
if (ap == NULL)
break;
na++;
if (ap == -1) {
error = EFAULT;
break;
}
do {
if (cc <= 0) {
/*
* We depend on NCARGS being a multiple of
* CLSIZE*NBPG. This way we need only check
* overflow before each buffer allocation.
*/
if (nc >= NCARGS-1) {
error = E2BIG;
break;
}
if (bp)
bdwrite(bp);
cc = CLSIZE*NBPG;
bp = getblk(argdev, bno + ctod(nc/NBPG), cc);
cp = bp->b_un.b_addr;
}
if (indir && na == 2 && sharg != NULL)
error = copystr(sharg, cp, cc, &len);
else
error = copyinstr((caddr_t)ap, cp, cc, &len);
ap += len;
cp += len;
nc += len;
cc -= len;
} while (error == ENOENT);
if (error) {
u.u_error = error;
if (bp)
brelse(bp);
bp = 0;
goto badarg;
}
}
if (bp)
bdwrite(bp);
bp = 0;
nc = (nc + NBPW-1) & ~(NBPW-1);
if (indir) {
ndp->ni_dent.d_namlen = strlen(cfname);
bcopy((caddr_t)cfname, (caddr_t)ndp->ni_dent.d_name,
(unsigned)(ndp->ni_dent.d_namlen + 1));
}
getxfile(ip, &exdata.ex_exec, nc + (na+4)*NBPW, uid, gid);
if (u.u_error) {
badarg:
for (cc = 0; cc < nc; cc += CLSIZE*NBPG) {
bp = baddr(argdev, bno + ctod(cc/NBPG), CLSIZE*NBPG);
if (bp) {
bp->b_flags |= B_AGE; /* throw away */
bp->b_flags &= ~B_DELWRI; /* cancel io */
brelse(bp);
bp = 0;
}
}
goto bad;
}
/*
* Copy back arglist.
*/
ucp = USRSTACK - nc - NBPW;
ap = ucp - na*NBPW - 3*NBPW;
u.u_ar0[SP] = ap;
(void) suword((caddr_t)ap, na-ne);
nc = 0;
cc = 0;
for (;;) {
ap += NBPW;
if (na == ne) {
(void) suword((caddr_t)ap, 0);
ap += NBPW;
}
if (--na < 0)
break;
(void) suword((caddr_t)ap, ucp);
do {
if (cc <= 0) {
if (bp)
brelse(bp);
cc = CLSIZE*NBPG;
bp = bread(argdev, bno + ctod(nc / NBPG), cc);
bp->b_flags |= B_AGE; /* throw away */
bp->b_flags &= ~B_DELWRI; /* cancel io */
cp = bp->b_un.b_addr;
}
error = copyoutstr(cp, (caddr_t)ucp, cc, &len);
ucp += len;
cp += len;
nc += len;
cc -= len;
} while (error == ENOENT);
if (error == EFAULT)
panic("exec: EFAULT");
}
(void) suword((caddr_t)ap, 0);
setregs(exdata.ex_exec.a_entry);
/*
* Remember file name for accounting.
*/
u.u_acflag &= ~AFORK;
bcopy((caddr_t)ndp->ni_dent.d_name, (caddr_t)u.u_comm,
(unsigned)(ndp->ni_dent.d_namlen + 1));
bad:
if (bp)
brelse(bp);
if (bno)
rmfree(argmap, (long)ctod(clrnd((int) btoc(NCARGS))), bno);
iput(ip);
}
/*
* Read in and set up memory for executed file.
*/
getxfile(ip, ep, nargc, uid, gid)
register struct inode *ip;
register struct exec *ep;
int nargc, uid, gid;
{
register size_t ts, ds, ss;
int pagi;
if (ep->a_magic == 0413)
pagi = SPAGI;
else
pagi = 0;
if (ep->a_text != 0 && (ip->i_flag&ITEXT) == 0 &&
ip->i_count != 1) {
register struct file *fp;
for (fp = file; fp < fileNFILE; fp++) {
if (fp->f_type == DTYPE_INODE &&
fp->f_count > 0 &&
(struct inode *)fp->f_data == ip &&
(fp->f_flag&FWRITE)) {
u.u_error = ETXTBSY;
goto bad;
}
}
}
/*
* Compute text and data sizes and make sure not too large.
*/
ts = clrnd(btoc(ep->a_text));
ds = clrnd(btoc(ep->a_data + ep->a_bss));
ss = clrnd(SSIZE + btoc(nargc));
if (chksize((unsigned)ts, (unsigned)ds, (unsigned)ss))
goto bad;
/*
* Make sure enough space to start process.
*/
u.u_cdmap = zdmap;
u.u_csmap = zdmap;
if (swpexpand(ds, ss, &u.u_cdmap, &u.u_csmap) == NULL)
goto bad;
/*
* At this point, committed to the new image!
* Release virtual memory resources of old process, and
* initialize the virtual memory of the new process.
* If we resulted from vfork(), instead wakeup our
* parent who will set SVFDONE when he has taken back
* our resources.
*/
if ((u.u_procp->p_flag & SVFORK) == 0)
vrelvm();
else {
u.u_procp->p_flag &= ~SVFORK;
u.u_procp->p_flag |= SKEEP;
wakeup((caddr_t)u.u_procp);
while ((u.u_procp->p_flag & SVFDONE) == 0)
sleep((caddr_t)u.u_procp, PZERO - 1);
u.u_procp->p_flag &= ~(SVFDONE|SKEEP);
}
u.u_procp->p_flag &= ~(SPAGI|SSEQL|SUANOM|SOUSIG);
u.u_procp->p_flag |= pagi;
u.u_dmap = u.u_cdmap;
u.u_smap = u.u_csmap;
vgetvm(ts, ds, ss);
if (pagi == 0)
u.u_error =
rdwri(UIO_READ, ip,
(char *)ctob(dptov(u.u_procp, 0)),
(int)ep->a_data,
(int)(sizeof (struct exec) + ep->a_text),
0, (int *)0);
xalloc(ip, ep, pagi);
if (pagi && u.u_procp->p_textp)
vinifod((struct fpte *)dptopte(u.u_procp, 0),
PG_FTEXT, u.u_procp->p_textp->x_iptr,
(long)(1 + ts/CLSIZE), (int)btoc(ep->a_data));
#ifdef vax
/* THIS SHOULD BE DONE AT A LOWER LEVEL, IF AT ALL */
mtpr(TBIA, 0);
#endif
if (u.u_error)
swkill(u.u_procp, "i/o error mapping pages");
/*
* set SUID/SGID protections, if no tracing
*/
if ((u.u_procp->p_flag&STRC)==0) {
u.u_uid = uid;
u.u_procp->p_uid = uid;
u.u_gid = gid;
} else
psignal(u.u_procp, SIGTRAP);
u.u_tsize = ts;
u.u_dsize = ds;
u.u_ssize = ss;
u.u_prof.pr_scale = 0;
bad:
return;
}
/*
* Clear registers on exec
*/
setregs(entry)
u_long entry;
{
register int i;
register struct proc *p = u.u_procp;
/*
* Reset caught signals. Held signals
* remain held through p_sigmask.
*/
while (p->p_sigcatch) {
(void) spl6();
i = ffs(p->p_sigcatch);
p->p_sigcatch &= ~(1 << (i - 1));
u.u_signal[i] = SIG_DFL;
(void) spl0();
}
#ifdef notdef
/* should pass args to init on the stack */
for (rp = &u.u_ar0[0]; rp < &u.u_ar0[16];)
*rp++ = 0;
#endif
u.u_ar0[PC] = entry + 2;
for (i=0; i<NOFILE; i++) {
if (u.u_pofile[i]&UF_EXCLOSE) {
closef(u.u_ofile[i]);
u.u_ofile[i] = NULL;
u.u_pofile[i] = 0;
}
u.u_pofile[i] &= ~UF_MAPPED;
}
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.