Net2/usr/src/bin/csh/exec.c
/*-
* Copyright (c) 1980, 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)exec.c 5.17 (Berkeley) 6/17/91";
#endif /* not lint */
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if __STDC__
# include <stdarg.h>
#else
# include <varargs.h>
#endif
#include "csh.h"
#include "extern.h"
/*
* System level search and execute of a command. We look in each directory
* for the specified command name. If the name contains a '/' then we
* execute only the full path name. If there is no search path then we
* execute only full path names.
*/
extern char **environ;
/*
* As we search for the command we note the first non-trivial error
* message for presentation to the user. This allows us often
* to show that a file has the wrong mode/no access when the file
* is not in the last component of the search path, so we must
* go on after first detecting the error.
*/
static char *exerr; /* Execution error message */
static Char *expath; /* Path for exerr */
/*
* Xhash is an array of HSHSIZ bits (HSHSIZ / 8 chars), which are used
* to hash execs. If it is allocated (havhash true), then to tell
* whether ``name'' is (possibly) present in the i'th component
* of the variable path, you look at the bit in xhash indexed by
* hash(hashname("name"), i). This is setup automatically
* after .login is executed, and recomputed whenever ``path'' is
* changed.
* The two part hash function is designed to let texec() call the
* more expensive hashname() only once and the simple hash() several
* times (once for each path component checked).
* Byte size is assumed to be 8.
*/
#define HSHSIZ 8192 /* 1k bytes */
#define HSHMASK (HSHSIZ - 1)
#define HSHMUL 243
static char xhash[HSHSIZ / 8];
#define hash(a, b) ((a) * HSHMUL + (b) & HSHMASK)
#define bit(h, b) ((h)[(b) >> 3] & 1 << ((b) & 7)) /* bit test */
#define bis(h, b) ((h)[(b) >> 3] |= 1 << ((b) & 7)) /* bit set */
static int hits, misses;
/* Dummy search path for just absolute search when no path */
static Char *justabs[] = {STRNULL, 0};
static void pexerr __P((void));
static void texec __P((Char *, Char **));
static int hashname __P((Char *));
void
doexec(t)
register struct command *t;
{
register Char *dp, **pv, **av, *sav;
register struct varent *v;
register bool slash;
register int hashval = 0, hashval1, i;
Char *blk[2];
/*
* Glob the command name. We will search $path even if this does something,
* as in sh but not in csh. One special case: if there is no PATH, then we
* execute only commands which start with '/'.
*/
blk[0] = t->t_dcom[0];
blk[1] = 0;
gflag = 0, tglob(blk);
if (gflag) {
pv = globall(blk);
if (pv == 0) {
setname(short2str(blk[0]));
stderror(ERR_NAME | ERR_NOMATCH);
}
gargv = 0;
}
else
pv = saveblk(blk);
trim(pv);
exerr = 0;
expath = Strsave(pv[0]);
Vexpath = expath;
v = adrof(STRpath);
if (v == 0 && expath[0] != '/') {
blkfree(pv);
pexerr();
}
slash = any(short2str(expath), '/');
/*
* Glob the argument list, if necessary. Otherwise trim off the quote bits.
*/
gflag = 0;
av = &t->t_dcom[1];
tglob(av);
if (gflag) {
av = globall(av);
if (av == 0) {
blkfree(pv);
setname(short2str(expath));
stderror(ERR_NAME | ERR_NOMATCH);
}
gargv = 0;
}
else
av = saveblk(av);
blkfree(t->t_dcom);
t->t_dcom = blkspl(pv, av);
xfree((ptr_t) pv);
xfree((ptr_t) av);
av = t->t_dcom;
trim(av);
if (*av == NULL || **av == '\0')
pexerr();
xechoit(av); /* Echo command if -x */
/*
* Since all internal file descriptors are set to close on exec, we don't
* need to close them explicitly here. Just reorient ourselves for error
* messages.
*/
SHIN = 0;
SHOUT = 1;
SHDIAG = 2;
OLDSTD = 0;
/*
* We must do this AFTER any possible forking (like `foo` in glob) so that
* this shell can still do subprocesses.
*/
(void) sigsetmask((sigset_t) 0);
/*
* If no path, no words in path, or a / in the filename then restrict the
* command search.
*/
if (v == 0 || v->vec[0] == 0 || slash)
pv = justabs;
else
pv = v->vec;
sav = Strspl(STRslash, *av);/* / command name for postpending */
Vsav = sav;
if (havhash)
hashval = hashname(*av);
i = 0;
hits++;
do {
/*
* Try to save time by looking at the hash table for where this command
* could be. If we are doing delayed hashing, then we put the names in
* one at a time, as the user enters them. This is kinda like Korn
* Shell's "tracked aliases".
*/
if (!slash && pv[0][0] == '/' && havhash) {
hashval1 = hash(hashval, i);
if (!bit(xhash, hashval1))
goto cont;
}
if (pv[0][0] == 0 || eq(pv[0], STRdot)) /* don't make ./xxx */
texec(*av, av);
else {
dp = Strspl(*pv, sav);
Vdp = dp;
texec(dp, av);
Vdp = 0;
xfree((ptr_t) dp);
}
misses++;
cont:
pv++;
i++;
} while (*pv);
hits--;
Vsav = 0;
xfree((ptr_t) sav);
pexerr();
}
static void
pexerr()
{
/* Couldn't find the damn thing */
if (expath) {
setname(short2str(expath));
Vexpath = 0;
xfree((ptr_t) expath);
expath = 0;
}
else
setname("");
if (exerr)
stderror(ERR_NAME | ERR_STRING, exerr);
stderror(ERR_NAME | ERR_COMMAND);
}
/*
* Execute command f, arg list t.
* Record error message if not found.
* Also do shell scripts here.
*/
static void
texec(sf, st)
Char *sf;
register Char **st;
{
register char **t;
register char *f;
register struct varent *v;
register Char **vp;
Char *lastsh[2];
int fd;
unsigned char c;
Char *st0, **ost;
/* The order for the conversions is significant */
t = short2blk(st);
f = short2str(sf);
Vt = t;
errno = 0; /* don't use a previous error */
(void) execve(f, t, environ);
Vt = 0;
blkfree((Char **) t);
switch (errno) {
case ENOEXEC:
/*
* From: casper@fwi.uva.nl (Casper H.S. Dik) If we could not execute
* it, don't feed it to the shell if it looks like a binary!
*/
if ((fd = open(f, O_RDONLY)) != -1) {
if (read(fd, (char *) &c, 1) == 1) {
if (!Isprint(c) && (c != '\n' && c != '\t')) {
(void) close(fd);
/*
* We *know* what ENOEXEC means.
*/
stderror(ERR_ARCH, f, strerror(errno));
}
}
#ifdef _PATH_BSHELL
else
c = '#';
#endif
(void) close(fd);
}
/*
* If there is an alias for shell, then put the words of the alias in
* front of the argument list replacing the command name. Note no
* interpretation of the words at this point.
*/
v = adrof1(STRshell, &aliases);
if (v == 0) {
vp = lastsh;
vp[0] = adrof(STRshell) ? value(STRshell) : STR_SHELLPATH;
vp[1] = NULL;
#ifdef _PATH_BSHELL
if (fd != -1 && c != '#')
vp[0] = STR_BSHELL;
#endif
}
else
vp = v->vec;
st0 = st[0];
st[0] = sf;
ost = st;
st = blkspl(vp, st); /* Splice up the new arglst */
ost[0] = st0;
sf = *st;
/* The order for the conversions is significant */
t = short2blk(st);
f = short2str(sf);
xfree((ptr_t) st);
Vt = t;
(void) execve(f, t, environ);
Vt = 0;
blkfree((Char **) t);
/* The sky is falling, the sky is falling! */
case ENOMEM:
stderror(ERR_SYSTEM, f, strerror(errno));
case ENOENT:
break;
default:
if (exerr == 0) {
exerr = strerror(errno);
if (expath)
xfree((ptr_t) expath);
expath = Strsave(sf);
Vexpath = expath;
}
}
}
/*ARGSUSED*/
void
execash(t, kp)
char **t;
register struct command *kp;
{
if (chkstop == 0 && setintr)
panystop(0);
rechist();
(void) signal(SIGINT, parintr);
(void) signal(SIGQUIT, parintr);
(void) signal(SIGTERM, parterm); /* if doexec loses, screw */
lshift(kp->t_dcom, 1);
exiterr = 1;
doexec(kp);
/* NOTREACHED */
}
void
xechoit(t)
Char **t;
{
if (adrof(STRecho)) {
flush();
haderr = 1;
blkpr(t), xputchar('\n');
haderr = 0;
}
}
/*VARARGS0*/
void
dohash()
{
DIR *dirp;
register struct dirent *dp;
register int cnt;
int i = 0;
struct varent *v = adrof(STRpath);
Char **pv;
int hashval;
havhash = 1;
for (cnt = 0; cnt < sizeof xhash; cnt++)
xhash[cnt] = 0;
if (v == 0)
return;
for (pv = v->vec; *pv; pv++, i++) {
if (pv[0][0] != '/')
continue;
dirp = opendir(short2str(*pv));
if (dirp == NULL)
continue;
while ((dp = readdir(dirp)) != NULL) {
if (dp->d_ino == 0)
continue;
if (dp->d_name[0] == '.' &&
(dp->d_name[1] == '\0' ||
dp->d_name[1] == '.' && dp->d_name[2] == '\0'))
continue;
hashval = hash(hashname(str2short(dp->d_name)), i);
bis(xhash, hashval);
/* tw_add_comm_name (dp->d_name); */
}
(void) closedir(dirp);
}
}
void
dounhash()
{
havhash = 0;
}
void
hashstat()
{
if (hits + misses)
xprintf("%d hits, %d misses, %d%%\n",
hits, misses, 100 * hits / (hits + misses));
}
/*
* Hash a command name.
*/
static int
hashname(cp)
register Char *cp;
{
register long h = 0;
while (*cp)
h = hash(h, *cp++);
return ((int) h);
}