2BSD/src/csh/sh.c
/* Copyright (c) 1979 Regents of the University of California */
#include "sh.h"
/*
* C Shell
*
* Bill Joy, UC Berkeley
* October, 1978
*/
char *pathlist[] = { SRCHPATH, 0 };
main(c, av)
int c;
char **av;
{
register char **v, *cp;
int nofile = 0;
int reenter = 0;
bool nverbose = 0, nexececho = 0, quitit = 0, fast = 0, prompt = 1;
char *hp;
settimes(); /* Immed. estab. timing base */
hp = getenv("HOME");
v = av;
if (eq(v[0], "a.out")) /* A.out's are quittable */
quitit = 1;
uid = getuid();
#ifdef V6
loginsh = eq(*v, "-"); /* To do .login/.logout */
#else
loginsh = **v == '-';
#endif
if (loginsh)
time(&chktim);
/*
* Move the descriptors to safe places.
* The variable didfds is 0 while we have only FSH* to work with.
* When didfds is true, we have 0,1,2 and prefer to use these.
*/
initdesc();
/*
* Initialize the shell variables.
* ARGV and PROMPT are initialized later.
* STATUS is also munged in several places.
* CHILD is munged when forking/waiting
*/
set("status", "0");
if (hp == 0)
fast++; /* No home -> can't read scripts */
else
set("home", hp);
if (uid == 0)
pathlist[0] = "/etc";
set1("path", saveblk(pathlist), &shvhed);
/*
* Re-initialize path if set in environment
*
cp = getenv("PATH");
if (cp != 0) {
register int i = 0;
register char *dp;
register char **pv;
for (dp = cp; *dp; dp++)
if (*dp == ':')
i++;
pv = calloc(i+1, sizeof (char **));
dp = cp;
i = 0;
while (*dp) {
if (*dp == ':') {
*dp = 0;
pv[i++] = savestr(cp);
*dp = ':';
} else if (*dp == 0) {
pv[i++] = savestr(cp);
break;
}
dp++;
}
pv[i] = 0;
set1("path", pv, &shvhed);
}
*/
set("shell", SHELLPATH);
doldol = putn(getpid()); /* For $$ */
shtemp = strspl("/tmp/sh", doldol); /* For << */
/*
* Record the interrupt states from the parent process.
* If the parent is non-interruptible our hand must be forced
* or we (and our children) won't be either.
* Our children inherit termination from our parent.
* We catch it only if we are the login shell.
*/
parintr = signal(SIGINT, SIG_IGN); /* parents interruptibility */
signal(SIGINT, parintr); /* ... restore */
parterm = signal(SIGTERM, SIG_IGN); /* parents terminability */
signal(SIGTERM, parterm); /* ... restore */
/*
* Process the arguments.
*
* Note that processing of -v/-x is actually delayed till after
* script processing.
*
* We set the first character of our name to be '-' if we are
* a shell running interruptible commands. Many programs which
* examine ps'es use this to filter such shells out.
*/
c--, v++;
while (c > 0 && (cp = v[0])[0] == '-') {
do switch (*cp++) {
case 0: /* - Interruptible, no prompt */
prompt = 0;
**av = '-';
nofile++;
break;
case 'c': /* -c Command input from arg */
if (c == 1)
exit(0);
c--, v++;
arginp = v[0];
prompt = 0;
nofile++;
break;
case 'e': /* -e Exit on any error */
exiterr++;
break;
case 'f': /* -f Fast start */
fast++;
break;
case 'i': /* -i Interactive, even if !intty */
intact++;
**av = '-';
nofile++;
break;
case 'n': /* -n Don't execute */
noexec++;
break;
case 'q': /* -q (Undoc'd) ... die on quit */
quitit = 1;
break;
case 's': /* -s Read from std input */
nofile++;
if (isatty(SHIN))
**v = '-';
break;
case 't': /* -t Read one line from input */
onelflg = 2;
if (isatty(SHIN))
**v = '-';
prompt = 0;
nofile++;
break;
case 'v': /* -v Echo hist expanded input */
nverbose = 1; /* ... later */
break;
case 'x': /* -x Echo just before execution */
nexececho = 1; /* ... later */
break;
case 'V': /* -V Echo hist expanded input */
setNS("verbose"); /* NOW! */
break;
case 'X': /* -X Echo just before execution */
setNS("echo"); /* NOW! */
break;
} while (*cp);
v++, c--;
}
if (quitit) /* With all due haste, for debugging */
signal(SIGQUIT, SIG_DFL);
/*
* Unless prevented by -, -c, -i, -s, or -t, if there
* are remaining arguments the first of them is the name
* of a shell file from which to read commands.
*/
if (nofile == 0 && c > 0) {
nofile = open(v[0], 0);
if (nofile < 0) {
child++; /* So this ... */
Perror(v[0]); /* ... doesn't return */
}
file = v[0];
SHIN = dmove(nofile, FSHIN); /* Replace FSHIN */
prompt = 0;
c--, v++;
}
/*
* Consider input a tty if it really is or we are interactive.
*/
intty = intact || isatty(SHIN);
#ifdef TELL
settell();
#endif
/*
* Commands are interruptible if we are interactive
* or the process which created us was.
*/
if (intact || parintr == SIG_DFL)
**av = '-';
/*
* Save the remaining arguments in ARGV.
* Normally the system-supplied argument list is ok as
* a zero terminated value block.
* On some version 6 systems, it is -1 terminated and setting it
* to zero messes up "ps" so we change it to zero, copy
* the block of pointers, and put it back the way it was.
*/
/*
if (c == 0)
set("argv", 0);
else
*/
if ((int) v[c] == -1) {
/* ick */
v[c] = 0, setq("argv", copyblk(v), &shvhed), v[c] = (char *) -1;
} else
setq("argv", v, &shvhed);
/*
* Set up the prompt.
*/
if (prompt)
set("prompt", uid == 0 ? "# " : "% ");
/*
* If we are an interactive shell, then start fiddling
* with the signals; this is a tricky game.
*/
if (**av == '-') {
setintr++;
if (!quitit) /* Wary! */
signal(SIGQUIT, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
}
/*
* Set an exit here in case of an interrupt or error reading
* the shell start-up scripts.
*/
setexit();
haderr = 0; /* In case second time through */
if (!fast && reenter == 0) {
reenter++;
/* Will have value("home") here because set fast if don't */
srccat(value("home"), "/.cshrc");
if (loginsh)
#ifdef NOHELP
srccat("", ".login");
#else
srccat(value("home"), "/.login");
#endif
}
/*
* Now are ready for the -v and -x flags
*/
if (nverbose)
setNS("verbose");
if (nexececho)
setNS("echo");
/*
* All the rest of the world is inside this call.
* The argument to process indicates whether it should
* catch "error unwinds". Thus if we are a interactive shell
* our call here will never return by being blown past on an error.
*/
process(setintr);
/*
* Mop-up.
*/
if (loginsh) {
printf("logout\n");
close(SHIN);
child++;
goodbye();
}
exitstat();
}
/*
* Source to the file which is the catenation of the argument names.
*/
srccat(cp, dp)
char *cp, *dp;
{
register char *ep = strspl(cp, dp);
register int unit = dmove(open(ep, 0), -1);
/* ioctl(unit, FIOCLEX, NULL); */
xfree(ep);
#ifdef INGRES
srcunit(unit, 0);
#else
srcunit(unit, 1);
#endif
}
/*
* Source to a unit. If onlyown it must be our file or
* we don't chance it. This occurs on ".cshrc"s and the like.
*/
srcunit(unit, onlyown)
register int unit;
bool onlyown;
{
/* We have to push down a lot of state here */
/* All this could go into a structure */
int oSHIN = -1, oldintty = intty;
struct whyle *oldwhyl = whyles;
char *ogointr = gointr, *oarginp = arginp;
int oonelflg = onelflg;
#ifdef TELL
bool otell = cantell;
#endif
struct Bin saveB;
/* The (few) real local variables */
jmp_buf oldexit;
int reenter;
register int (*oldint)();
if (unit < 0)
return;
if (onlyown) {
struct stat stb;
#ifdef CC
if (fstat(unit, &stb) < 0 || (stb.st_uid != uid && stb.st_uid != (uid &~ 0377))) {
#endif
#ifdef CORY
if (fstat(unit, &stb) < 0 || (stb.st_uid != uid && stb.st_uid != (uid &~ 0377))) {
#endif
#ifndef CC
#ifndef CORY
if (fstat(unit, &stb) < 0 || stb.st_uid != uid) {
#endif
#endif
close(unit);
return;
}
}
/*
* There is a critical section here while we are pushing down the
* input stream since we have stuff in different structures.
* If we weren't careful an interrupt could corrupt SHIN's Bin
* structure and kill the shell.
*
* We could avoid the critical region by grouping all the stuff
* in a single structure and pointing at it to move it all at
* once. This is less efficient globally on many variable references
* however.
*/
getexit(oldexit);
reenter = 0;
oldint = signal(SIGINT, SIG_IGN);
setexit();
reenter++;
if (reenter == 1) {
/* Setup the new values of the state stuff saved above */
copy(&saveB, &B, sizeof saveB);
fbuf = (char **) 0;
fseekp = feobp = fblocks = 0;
oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
intty = isatty(SHIN), whyles = 0, gointr = 0;
/*
* Now if we are allowing commands to be interrupted,
* we let ourselves be interrupted.
*/
signal(SIGINT, setintr ? pintr : oldint);
#ifdef TELL
settell();
#endif
process(0); /* 0 -> blow away on errors */
}
signal(SIGINT, oldint);
if (oSHIN >= 0) {
register int i;
/* We made it to the new state... free up its storage */
/* This code could get run twice but xfree doesn't care */
for (i = 0; i < fblocks; i++)
xfree(fbuf[i]);
xfree(fbuf);
/* Reset input arena */
copy(&B, &saveB, sizeof B);
close(SHIN), SHIN = oSHIN;
arginp = oarginp, onelflg = oonelflg;
intty = oldintty, whyles = oldwhyl, gointr = ogointr;
#ifdef TELL
cantell = otell;
#endif
}
resexit(oldexit);
/*
* If process reset() (effectively an unwind) then
* we must also unwind.
*/
if (reenter >= 2)
error(0);
}
goodbye()
{
if (loginsh) {
signal(SIGQUIT, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
setintr = 0; /* No interrupts after "logout" */
if (adrof("home"))
srccat(value("home"), "/.logout");
}
exitstat();
}
exitstat()
{
/*
* Note that if STATUS is corrupted (i.e. getn bombs)
* then error will exit directly because we poke child here.
* Otherwise we might continue unwarrantedly (sic).
*/
child++;
exit(getn(value("status")));
}
/*
* Catch an interrupt, e.g. during lexical input.
* If we are an interactive shell, we reset the interrupt catch
* immediately. In any case we drain the shell output,
* and finally go through the normal error mechanism, which
* gets a chance to make the shell go away.
*/
pintr()
{
if (setintr)
signal(SIGINT, SIG_IGN);
draino();
/*
* If we have an active "onintr" then we search for the label.
* Note that if one does "onintr -" then we shan't be interruptible
* so we needn't worry about that here.
*/
if (gointr) {
search(ZGOTO, 0, gointr);
timflg = 0;
reset();
} else if (intty)
printf("\n"); /* Some like this, others don't */
error(0);
}
/*
* Process is the main driving routine for the shell.
* It runs all command processing, except for those within { ... }
* in expressions (which is run by a routine evalav in sh.exp.c which
* is a stripped down process), and `...` evaluation which is run
* also by a subset of this code in sh.glob.c in the routine backeval.
*
* The code here is a little strange because part of it is interruptible
* and hence freeing of structures appears to occur when none is necessary
* if this is ignored.
*
* Note that if catch is not set then we will unwind on any error.
* In an end-of-file occurs, we return.
*/
process(catch)
bool catch;
{
register char *cp;
jmp_buf osetexit;
struct wordent paraml;
struct command *t;
getexit(osetexit);
for (;;) {
paraml.next = paraml.prev = ¶ml;
paraml.word = "";
t = 0;
setexit();
justpr = 0; /* A chance to execute */
/*
* Interruptible during interactive reads
*/
if (setintr)
signal(SIGINT, pintr);
/*
* For the sake of reset()
*/
freelex(¶ml), freesyn(t), t = 0;
if (haderr) {
if (!catch) {
/* unwind */
doneinp = 0;
resexit(osetexit);
reset();
}
haderr = 0;
/*
* Every error is eventually caught here or
* the shell dies. It is at this
* point that we clean up any left-over open
* files, by closing all but a fixed number
* of pre-defined files. Thus routines don't
* have to worry about leaving files open due
* to deeper errors... they will get closed here.
*/
closem();
continue;
}
if (doneinp) {
doneinp = 0;
break;
}
if (intty) {
mailchk();
/*
* If we are at the end of the input buffer
* then we are going to read fresh stuff.
* Otherwise, we are rereading input and don't
* need or want to prompt.
*/
if (fseekp == feobp)
if (!whyles)
for (cp = value("prompt"); *cp; cp++)
if (*cp == '!')
printf("%d", eventno + 1);
else {
if (*cp == '\\' && cp[1] == '!')
cp++;
putchar(*cp | QUOTE);
}
else
/*
* Prompt for forward reading loop
* body content.
*/
printf("? ");
flush();
}
err = 0;
/*
* Echo not only on VERBOSE, but also with history expansion.
* If there is a lexical error then we forego history echo.
*/
if (lex(¶ml) && !err && intty || adrof("verbose")) {
haderr = 1;
prlex(¶ml);
haderr = 0;
}
/*
* The parser may lose space if interrupted.
*/
if (setintr)
signal(SIGINT, SIG_IGN);
/*
* Save input text on the history list if it
* is from the terminal at the top level and not
* in a loop.
*/
if (catch && intty && !whyles)
savehist(¶ml);
/*
* Print lexical error messages.
*/
if (err)
error(err);
/*
* If had a history command :p modifier then
* this is as far as we should go
*/
if (justpr)
reset();
alias(¶ml);
/*
* Parse the words of the input into a parse tree.
*/
t = syntax(paraml.next, ¶ml);
if (err)
error(err);
/*
* Execute the parse tree
*/
execute(t);
/*
* Made it!
*/
freelex(¶ml), freesyn(t);
}
resexit(osetexit);
}
dosource(t)
register char **t;
{
register char *f;
register int u;
t++;
f = globone(*t);
u = dmove(open(f, 0), -1);
xfree(f);
if (u < 0)
Perror(f);
srcunit(u, 0);
}
/*
* Check for mail.
* If we are a login shell, then we don't want to tell
* about any mail file unless its been modified
* after the time we started.
* This prevents us from telling the user things he already
* knows, since the login program insist on saying
* "You have mail."
*/
mailchk()
{
register struct varent *v;
register char **vp;
time_t t;
int intvl, cnt;
v = adrof("mail");
if (v == 0)
return;
time(&t);
vp = v->vec;
cnt = blklen(vp);
intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
if (intvl < 1)
intvl = 1;
if (chktim + intvl > t)
return;
for (; *vp; vp++) {
bool new;
struct stat stb;
if (stat(*vp, &stb) < 0)
continue;
/*
* We assume that a file has been read if the access time is
* greater than the mod time.
*/
#ifndef CORY
if (stb.st_size == 0)
continue;
#endif
if (stb.st_atime > stb.st_mtime || stb.st_atime < chktim)
continue;
new = stb.st_mtime > time0;
if (loginsh && !new)
continue;
if (cnt == 1)
printf("You have %smail.\n", new ? "new " : "");
else
printf("%s in %s.\n", new ? "New mail" : "Mail", *vp);
}
chktim = t;
}
#include <pwd.h>
/*
* Extract a home directory from the password file
* The argument points to a buffer where the name of the
* user whose home directory is sought is currently.
* We write the home directory of the user back there.
*/
gethdir(home)
char *home;
{
register struct passwd *pp = getpwnam(home);
if (pp == 0)
return (1);
strcpy(home, pp->pw_dir);
return (0);
}
/*
* Move the initial descriptors to their eventual
* resting places, closin all other units.
*/
initdesc()
{
didcch = 0; /* Havent closed for child */
didfds = 0; /* 0, 1, 2 aren't set up */
SHIN = dcopy(0, FSHIN);
SHOUT = dcopy(1, FSHOUT);
SHDIAG = dcopy(2, FSHDIAG);
OLDSTD = dcopy(SHIN, FOLDSTD);
closem();
}
#ifndef V6
exit(i)
int i;
{
_exit(i);
}
#endif