1BSD/s1/sh.c
#
/*
* UC berkeley shell
*
* Modified by Bill Joy Oct 14, 1976
*
* library "lib"
* cd for "chdir"
* interruptible waits
* new accounting scheme
* interactive (login shell) option "-i"
* shells with input and output tty's ignore interrupts
* verbose option "-v" causes input commands to be echoed
* $* for all arguments $1 to end
* >* >>* and |* to put unit 2 there also
* `cmd1 ; ... ; cmdn &*' means `( cmd1 ; ... ; cmdn ) &'
* pascal objects are recognized and px's are forked
* gimme and normal
* working directory not searched for root
*/
char shell[] "/bin/sh";
char glob[] "/etc/glob2";
char px[] "/bin/px";
#define PCXN 0404
#define INTR 2
#define QUIT 3
#define LINSIZ 1000
#define ARGSIZ 50
#define TRESIZ 100
#define LIBSIZ 100
#define QUOTE 0200
#define FAND 1
#define FCAT 2
#define FPIN 4
#define FPOU 8
#define FPAR 16
#define FINT 32
#define FPRS 64
#define FDIAG 128
#define TCOM 1
#define TPAR 2
#define TFIL 3
#define TLST 4
#define DTYP 0
#define DLEF 1
#define DRIT 2
#define DFLG 3
#define DSPR 4
#define DCOM 5
#define ENOEXEC 8
#define ENOMEM 12
int niceness;
char *dolp;
int *dolnxt;
char pidp[7];
int dolc;
char **dolv;
char *promp "% ";
char *linep;
char **argp;
int *treep;
char peekc;
char gflg;
char nofile;
char error;
char acctf;
char *accpt;
char *accbuf;
int acct;
char acnm[] "/usr/adm/sha\0\0\0";
char ty;
char tyed;
char echo;
int uid;
char setintr;
char *arginp;
char onelflg;
char *mesg[] {
0,
"Hangup",
0,
"Quit",
"Illegal instruction",
"Trace/BPT trap",
"IOT trap",
"EMT trap",
"Floating exception",
"Killed",
"Bus error",
"Memory fault",
"Bad system call",
0,
"Alarm clock",
"Sig 15",
"Sig 16",
};
char line[LINSIZ];
char *args[ARGSIZ];
int trebuf[TRESIZ];
char *lib;
char *numpt &pidp[sizeof pidp - 1];
main(c, av)
int c;
char **av;
{
register f;
register char **v, *cp;
for(f=3; f<15; f++)
close(f);
numb(numb(getpid()));
if ((uid = getuid()) == 0)
promp[0] = '#';
v = av;
dolnxt = &v[c];
if (c > 1) {
if (*(cp = v[1]) == '-') {
do
switch(*cp++) {
case 'v':
echo++;
break;
case 'c':
if (c > 2)
arginp = v[2];
goto l1;
case 't':
onelflg = 2;
case '\0':
l1:
*promp = '\0';
case 'i':
**v = '-';
nofile++;
break;
}
while (*cp);
v++;
c--;
}
if (nofile == 0 && c > 1) {
close(0);
if (open(cp = v[1], 0) < 0) {
prs(v[1]);
err(": cannot open");
}
*promp = '\0';
}
}
if ((ty = ttyn(0)) != 'x' && ttyn(1) != 'x')
**v = '-';
if (**av == '-') {
setintr++;
signal(QUIT, 1);
signal(INTR, 1);
}
dolv = v+1;
dolc = c-1;
numpt = &acnm[sizeof acnm - 1];
numb((uid>>8) & 0377);
numb(uid & 0377);
if ((acctf = open(acnm, 1)) >= 0 || echo)
accbuf = sbrk(256);
setexit();
for(;;) {
prs(promp);
if ((cp = accbuf) != 0) {
*cp++ = ty;
tyed++;
*cp++ = ' ';
accpt = cp;
acct = 254;
}
peekc = getc();
main1();
}
}
numb(a)
{
register i, j;
i = a;
j = 3;
do {
*--numpt = (i % 10) | '0';
i =/ 10;
} while(--j);
return(i);
}
acflush()
{
register f, c;
register char *b;
if ((b = accbuf) != 0) {
c = 256 - acct;
if ((f = acctf)>= 0) {
seek(f, 0, 2);
write(f, b, c);
}
if (echo) {
if (tyed)
b[0] = uid ? '%' : '#';
seek(2, 0, 2);
write(2, b, c);
}
accpt = b;
acct = 256;
}
}
main1()
{
register char c, *cp;
register *t;
argp = args;
linep = line;
error = 0;
gflg = 0;
do {
cp = linep;
word();
} while(*cp != '\n');
treep = trebuf;
if (gflg == 0) {
if (error == 0)
t = syntax(args, argp);
if (error != 0)
err("syntax error");
else {
acflush();
execute(t);
}
}
}
word()
{
register char c, c1;
*argp++ = linep;
loop:
switch(c = getc()) {
case ' ':
case '\t':
goto loop;
case '\'':
case '"':
c1 = c;
while((c = readc()) != c1) {
if (c == '\n') {
error++;
peekc = c;
return;
}
*linep++ = c|QUOTE;
}
goto pack;
case '&':
*linep++ = c;
if ((c = getc()) == '*')
*linep++ = c;
else
peekc = c;
*linep++ = '\0';
return;
case ';':
case '<':
case '>':
case '(':
case ')':
case '|':
case '^':
case '\n':
*linep++ = c;
*linep++ = '\0';
return;
}
peekc = c;
pack:
for(;;) {
c = getc();
if (any(c, " '\"\t;&<>()|^\n")) {
peekc = c;
if (any(c, "\"'"))
goto loop;
*linep++ = '\0';
return;
}
*linep++ = c;
}
}
tree(n)
int n;
{
register *t;
t = treep;
treep =+ n;
if (treep > &trebuf[TRESIZ]) {
prs("Command line overflow\n");
error++;
reset(); /* UGH */
}
return(t);
}
getc()
{
register c;
if (peekc) {
c = peekc;
peekc = 0;
return(c);
}
if (argp > &args[ARGSIZ-5]) {
argp =- 10;
while((c=getc()) != '\n');
argp =+ 10;
err("Too many args");
gflg++;
return(c);
}
if (linep > &line[LINSIZ-5]) {
linep =- 10;
while((c=getc()) != '\n');
linep =+ 10;
err("Too many characters");
gflg++;
return(c);
}
for(;;) {
if (dolp) {
if ((c = *dolp++) != '\0')
return(c);
dolp = *dolnxt;
c = dolp;
if (c != -1) {
dolnxt++;
return(' ');
}
dolp = 0;
}
if ((c = readc()) == '\\')
if ((c = readc()) == '\n')
return(' ');
else
return(c | QUOTE);
else if (c == '$') {
c = readc();
if (c >= '0' && c <= '9') {
if (c - '0' < dolc)
dolp = dolv[c - '0'];
continue;
}
else if (c == '$') {
dolp = &pidp[1];
continue;
}
else if (c == '*') {
if (dolc > 1) {
dolp = dolv[1];
dolnxt = &dolv[2];
}
continue;
}
}
return(c&0177);
}
}
readc()
{
char cc;
register c;
register char *cp;
if (arginp) {
if (arginp == 1)
exit(0);
else if ((c = *arginp++) == '\0') {
arginp = 1;
c = '\n';
}
} else if (onelflg == 1 || read(0, &cc, 1) != 1)
exit(0);
else if ((c = cc) == '\n' && onelflg)
onelflg--;
if ((cp = accpt) != 0) {
*cp++ = c;
if (--acct == 0)
acflush();
else
accpt = cp;
}
return(c);
}
/*
* syntax
* empty
* syn1
*/
syntax(p1, p2)
char **p1, **p2;
{
while(p1 != p2) {
if (any(**p1, ";&\n"))
p1++;
else
return(syn1(p1, p2, 1));
}
return(0);
}
/*
* syn1@fl=0
* syn2
* syn2 ; syntax
* syn2 &
*
* When fl=1 syn1 handles the vagarities of &*
*/
syn1(p1, p2, fl)
char **p1, **p2;
{
register char **p;
register *t, *t1;
int l;
top:
l = 0;
for(p=p1; p!=p2; p++)
switch(**p) {
case '(':
l++;
continue;
case ')':
l--;
if (l < 0)
error++; /* too many ')'s */
continue;
case ';':
case '\n':
if (fl)
continue;
case '&':
if (l == 0) {
if (fl) {
l = (*p)[1];
if (l == '*')
**p = ';';
t1 = syn1(p1, p+1, 0);
if (l == '*')
if (t1[DTYP] == TLST) {
t = tree(5);
t[DTYP] = TPAR;
t[DLEF] = 0;
t[DRIT] = 0;
t[DFLG] = FAND|FPRS|FINT;
t[DSPR] = t1;
t1 = t;
} else {
t = t1[DLEF];
t[DFLG] =| FAND|FPRS|FINT;
}
} else {
l = **p;
t1 = syn2(p1, p);
if (l == '&')
t1[DFLG] =| FAND|FPRS|FINT;
}
t = tree(4);
t[DTYP] = TLST;
t[DFLG] = 0;
t[DLEF] = t1;
t[DRIT] = syntax(p+1, p2);
return(t);
}
}
if (l == 0)
if (fl) {
fl = 0;
goto top;
} else
return(syn2(p1, p2));
error++;
}
/*
* syn2
* syn3
* syn3 | syn2
*/
syn2(p1, p2)
char **p1, **p2;
{
register char **p;
register int l, *t;
l = 0;
for(p=p1; p!=p2; p++)
switch(**p) {
case '(':
l++;
continue;
case ')':
l--;
continue;
case '|':
case '^':
if (l == 0) {
t = tree(4);
t[DTYP] = TFIL;
t[DLEF] = syn3(p1, p);
p++;
if (p != p2 && **p == '*') {
t[DFLG] = FDIAG;
if ((*p)[1] != '\0') {
(*p)++;
p--;
}
} else {
t[DFLG] = 0;
p--;
}
t[DRIT] = syn2(p+1, p2);
return(t);
}
}
return(syn3(p1, p2));
}
/*
* syn3
* ( syn1@1 ) [ < in ] [ > out ]
* word word* [ < in ] [ > out ]
*/
syn3(p1, p2)
char **p1, **p2;
{
register char **p;
char **lp, **rp;
register *t;
int n, l, i, o, c, flg;
flg = 0;
if (**p2 == ')')
flg =| FPAR;
lp = 0;
rp = 0;
i = 0;
o = 0;
n = 0;
l = 0;
for(p=p1; p!=p2; p++)
switch(c = **p) {
case '(':
if (l == 0) {
if (lp != 0)
error++;
lp = p+1;
}
l++;
continue;
case ')':
l--;
if (l == 0)
rp = p;
continue;
case '>':
p++;
if (p!=p2 && **p=='>')
flg =| FCAT; else
p--;
p++;
if (p != p2 && **p == '*') {
flg =| FDIAG;
if ((*p)[1] != '\0') {
(*p)++;
p--;
}
} else
p--;
case '<':
if (l == 0) {
p++;
if (p == p2) {
error++;
p--;
}
if (any(**p, "<>("))
error++;
if (c == '<') {
if (i != 0)
error++;
i = *p;
} else {
if (o != 0)
error++;
o = *p;
}
}
continue;
default:
if (l == 0)
p1[n++] = *p;
}
if (lp != 0) {
if (n != 0)
error++;
t = tree(5);
t[DTYP] = TPAR;
t[DSPR] = syn1(lp, rp, 1);
} else {
if (n == 0)
error++;
p1[n++] = 0;
t = tree(n+5);
t[DTYP] = TCOM;
for(l=0; l<n; l++)
t[l+DCOM] = p1[l];
}
t[DFLG] = flg;
t[DLEF] = i;
t[DRIT] = o;
return(t);
}
scan(at, f)
int *at;
int (*f)();
{
register char *p, c;
register *t;
t = at+DCOM;
while(p = *t++)
while(c = *p)
*p++ = (*f)(c);
}
tglob(c)
int c;
{
if (any(c, "[?*"))
gflg = 1;
return(c);
}
trim(c)
int c;
{
return(c&0177);
}
endwait()
{
signal(INTR, 1);
prs("wait: interrupted\n");
reset(); /* URK! */
}
execute(t, pf1, pf2)
int *t, *pf1, *pf2;
{
int i, f, pv[2];
register *t1;
register char *cp1, *cp2;
char *scp;
extern errno;
if (t != 0)
switch(t[DTYP]) {
case TCOM:
cp1 = t[DCOM];
if (uid == 0) {
if (equal(cp1, "gimme")) {
nice(-20);
return;
}
if (equal(cp1, "normal")) {
nice(0);
return;
}
}
if (equal(cp1, "chdir") || equal(cp1, "cd")) {
if (t[DCOM+1] != 0) {
scan(t, &trim);
if (chdir(t[DCOM+1]) < 0) {
prs(cp1);
err(": bad directory");
}
} else {
prs(cp1);
err(": arg count");
}
return;
}
if (equal(cp1, "shift")) {
if (dolc < 1) {
prs("shift: no args\n");
return;
}
dolv[1] = dolv[0];
dolv++;
dolc--;
return;
}
if (equal(cp1, "lib")) {
if (cp2 = *(t1 = &t[DCOM+1])) {
if (!(cp1 = lib))
cp1 = lib = sbrk(LIBSIZ+1);
i = LIBSIZ;
for(;;) {
while(*cp1++ = (*cp2++ & 0177))
if (--i == 0) {
err("lib: path too long");
lib[0] = 0;
return;
}
if (!(cp2 = *++t1))
return;
*(cp1-1) = ' ';
}
} else {
prs(lib);
prs("\n");
}
return;
}
if (equal(cp1, "wait")) {
if (setintr && *promp) {
signal(INTR, endwait);
pwait(-1);
signal(INTR, 1);
} else
pwait(-1);
return;
}
if (equal(cp1, ":"))
return;
case TPAR:
t1 = t;
f = t1[DFLG];
i = 0;
if ((f&FPAR) == 0)
i = fork();
if (i == -1) {
err("try again");
return;
}
if (i != 0) {
if ((f&FPIN) != 0) {
close(pf1[0]);
close(pf1[1]);
}
if ((f&FPRS) != 0) {
prn(i);
prs("\n");
}
if ((f&FAND) != 0)
return;
if ((f&FPOU) == 0)
pwait(i);
return;
}
if ((cp1 = t1[DLEF]) != 0) {
close(0);
if (open(cp1, 0) < 0) {
prs(cp1);
err(": cannot open");
exit(1);
}
}
if ((cp2 = t1[DRIT]) != 0) {
close(1);
if ((f&FCAT) != 0 && open(cp2, 1) >= 0)
seek(1, 0, 2);
else if (creat(cp2, 0644) < 0) {
prs(t1[DRIT]);
err(": cannot create");
exit(1);
}
}
if ((f&FPIN) != 0) {
close(0);
dup(pf1[0]);
close(pf1[0]);
close(pf1[1]);
}
if ((f&FPOU) != 0) {
close(1);
dup(pf2[1]);
close(pf2[0]);
close(pf2[1]);
}
if (f&FDIAG) {
close(2);
dup(1);
}
if ((f&FINT)!=0 && t1[DLEF]==0 && (f&FPIN)==0) {
close(0);
open("/dev/null", 0);
}
if ((f&FINT) == 0 && setintr) {
signal(INTR, 0);
signal(QUIT, 0);
}
if (t1[DTYP] == TPAR) {
if (t1 = t1[DSPR])
t1[DFLG] =| f&FINT;
execute(t1);
exit(1);
}
close(acctf);
gflg = 0;
scan(t1+1, &tglob);
if (gflg) {
t1 = &t1[DSPR-1];
*t1++ = glob;
if ((*t1 = lib) == 0)
*t1 = &"";
t1--;
execv(*t1, t1);
prs("glob: cannot execute\n");
exit(1);
}
scan(t1, &trim);
cp1 = t1[DCOM];
while(*cp1 && *cp1 != '/')
cp1++;
if (*cp1 || uid)
texec(t1[DCOM], t1);
if (!*cp1) {
if (cp2 = lib)
for(;;) {
while (*cp2 == ' ')
cp2++;
if (!*cp2)
break;
cp1 = linep;
while(*cp2)
if (*cp2 == ' ')
break;
else
*cp1++ = *cp2++;
scp = cp2;
*cp1++ = '/';
cp2 = t[DCOM];
while(*cp1++ = *cp2++)
continue;
texec(linep, t1);
cp2 = scp;
}
cp1 = linep;
cp2 = "/usr/bin/";
while(*cp1 = *cp2++)
cp1++;
cp2 = t1[DCOM];
while(*cp1++ = *cp2++);
texec(linep+4, t1);
texec(linep, t1);
}
prs(t1[DCOM]);
err(": not found");
exit(1);
case TFIL:
f = t[DFLG];
pipe(pv);
t1 = t[DLEF];
t1[DFLG] =| FPOU | (f&(FPIN|FINT|FPRS|FDIAG));
execute(t1, pf1, pv);
t1 = t[DRIT];
t1[DFLG] =| FPIN | (f&(FPOU|FINT|FAND|FPRS));
execute(t1, pv, pf2);
return;
case TLST:
f = t[DFLG]&FINT;
if (t1 = t[DLEF])
t1[DFLG] =| f;
execute(t1);
if (t1 = t[DRIT])
t1[DFLG] =| f;
execute(t1);
return;
}
}
texec(f, at)
int *at;
{
extern errno;
register int *t, *t1;
register i;
int w;
t = at;
execv(f, (t1 = &t[DCOM]));
if (errno == ENOEXEC) {
*t1 = f;
*--t1 = shell;
i = open(f, 0);
if (i >= 0) {
if (read(i, &w, 2) == 2 && w == PCXN)
*t1 = px;
close(i);
}
execv(*t1, t1);
prs("No ");
prs(*t1);
err("!!\n");
exit(1);
} else if (errno==ENOMEM) {
prs(*t1);
err(": too large");
exit(1);
}
}
err(s)
char *s;
{
prs(s);
prs("\n");
if (*promp == '\0') {
seek(0, 0, 2);
exit();
}
}
prs(as)
char *as;
{
register char *s;
if (s = as) {
while(*s)
s++;
write(2, as, s-as);
}
}
prn(n)
int n;
{
register a;
if (a = n/10)
prn(a);
n = n % 10 + '0';
write(2, &n, 1);
}
getn(acp)
char *acp;
{
register i;
register char c, *cp;
cp = acp;
i = 0;
while ((c = *cp++) != '\0')
if (c >= '0' && c <= '9')
i = 10 * i + c - '0';
return(i);
}
any(c, as)
int c;
char *as;
{
register char *s;
s = as;
while(*s)
if (*s++ == c)
return(1);
return(0);
}
equal(as1, as2)
char *as1, *as2;
{
register char *s1, *s2;
s1 = as1;
s2 = as2;
while(*s1++ == *s2)
if (*s2++ == '\0')
return(1);
return(0);
}
pwait(ai)
int ai;
{
register p, e, i;
int s;
if ((i = ai) != 0)
do {
p = wait(&s);
if (p == -1)
break;
e = s & 0177;
if (mesg[e] != 0) {
if (p != i) {
prn(p);
prs(": ");
}
prs(mesg[e]);
if (s & 0200)
prs(" -- Core dumped");
}
if (e != 0)
err("");
} while (i != p);
}