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NetBSD/bin/csh/sem.c

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/* $NetBSD: sem.c,v 1.32 2020/02/05 20:06:17 fox Exp $ */
/*-
* Copyright (c) 1980, 1991, 1993
* 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. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)sem.c 8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: sem.c,v 1.32 2020/02/05 20:06:17 fox Exp $");
#endif
#endif /* not lint */
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "csh.h"
#include "extern.h"
#include "proc.h"
__dead static void vffree(int);
static Char *splicepipe(struct command *t, Char *);
static void doio(struct command *t, int *, int *);
static void chkclob(char *);
void
execute(struct command *t, int wtty, int *pipein, int *pipeout)
{
static sigset_t csigset, ocsigset;
static int nosigchld = 0, onosigchld = 0;
volatile int wanttty = wtty;
struct biltins * volatile bifunc;
int pv[2], pid;
sigset_t nsigset;
volatile int forked;
UNREGISTER(forked);
UNREGISTER(bifunc);
UNREGISTER(wanttty);
forked = 0;
pid = 0;
if (t == 0)
return;
if (t->t_dflg & F_AMPERSAND)
wanttty = 0;
switch (t->t_dtyp) {
case NODE_COMMAND:
if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE)
(void)Strcpy(t->t_dcom[0], t->t_dcom[0] + 1);
if ((t->t_dflg & F_REPEAT) == 0)
Dfix(t); /* $ " ' \ */
if (t->t_dcom[0] == 0)
return;
/* FALLTHROUGH */
case NODE_PAREN:
if (t->t_dflg & F_PIPEOUT)
mypipe(pipeout);
/*
* Must do << early so parent will know where input pointer should be.
* If noexec then this is all we do.
*/
if (t->t_dflg & F_READ) {
(void)close(0);
heredoc(t->t_dlef);
if (noexec)
(void)close(0);
}
set(STRstatus, Strsave(STR0));
/*
* This mess is the necessary kludge to handle the prefix builtins:
* nice, nohup, time. These commands can also be used by themselves,
* and this is not handled here. This will also work when loops are
* parsed.
*/
while (t->t_dtyp == NODE_COMMAND)
if (eq(t->t_dcom[0], STRnice)) {
if (t->t_dcom[1]) {
if (strchr("+-", t->t_dcom[1][0])) {
if (t->t_dcom[2]) {
setname("nice");
t->t_nice =
getn(t->t_dcom[1]);
lshift(t->t_dcom, 2);
t->t_dflg |= F_NICE;
}
else
break;
} else {
t->t_nice = 4;
lshift(t->t_dcom, 1);
t->t_dflg |= F_NICE;
}
} else
break;
} else if (eq(t->t_dcom[0], STRnohup)) {
if (t->t_dcom[1]) {
t->t_dflg |= F_NOHUP;
lshift(t->t_dcom, 1);
}
else
break;
} else if (eq(t->t_dcom[0], STRtime)) {
if (t->t_dcom[1]) {
t->t_dflg |= F_TIME;
lshift(t->t_dcom, 1);
}
else
break;
} else
break;
/* is it a command */
if (t->t_dtyp == NODE_COMMAND) {
/*
* Check if we have a builtin function and remember which one.
*/
bifunc = isbfunc(t);
if (noexec && bifunc != NULL) {
/*
* Continue for builtins that are part of the scripting language
*/
if (bifunc->bfunct != dobreak && bifunc->bfunct != docontin &&
bifunc->bfunct != doelse && bifunc->bfunct != doend &&
bifunc->bfunct != doforeach && bifunc->bfunct != dogoto &&
bifunc->bfunct != doif && bifunc->bfunct != dorepeat &&
bifunc->bfunct != doswbrk && bifunc->bfunct != doswitch &&
bifunc->bfunct != dowhile && bifunc->bfunct != dozip)
break;
}
}
else { /* not a command */
bifunc = NULL;
if (noexec)
break;
}
/*
* We fork only if we are timed, or are not the end of a parenthesized
* list and not a simple builtin function. Simple meaning one that is
* not pipedout, niced, nohupped, or &'d. It would be nice(?) to not
* fork in some of these cases.
*/
/*
* Prevent forking cd, pushd, popd, chdir cause this will cause the
* shell not to change dir!
*/
if (bifunc && (bifunc->bfunct == dochngd ||
bifunc->bfunct == dopushd ||
bifunc->bfunct == dopopd))
t->t_dflg &= ~(F_NICE);
if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 &&
(!bifunc || t->t_dflg &
(F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP)))) ||
/*
* We have to fork for eval too.
*/
(bifunc && (t->t_dflg & (F_PIPEIN | F_PIPEOUT)) != 0 &&
bifunc->bfunct == doeval)) {
if (t->t_dtyp == NODE_PAREN ||
t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) {
forked++;
/*
* We need to block SIGCHLD here, so that if the process does
* not die before we can set the process group
*/
if (wanttty >= 0 && !nosigchld) {
sigemptyset(&nsigset);
(void)sigaddset(&nsigset, SIGCHLD);
(void)sigprocmask(SIG_BLOCK, &nsigset, &csigset);
nosigchld = 1;
}
pid = pfork(t, wanttty);
if (pid == 0 && nosigchld) {
(void)sigprocmask(SIG_SETMASK, &csigset, NULL);
nosigchld = 0;
}
else if (pid != 0 && (t->t_dflg & F_AMPERSAND))
backpid = pid;
}
else {
int ochild, osetintr, ohaderr, odidfds;
int oSHIN, oSHOUT, oSHERR, oOLDSTD, otpgrp;
sigset_t osigset;
/*
* Prepare for the vfork by saving everything that the child
* corrupts before it exec's. Note that in some signal
* implementations which keep the signal info in user space
* (e.g. Sun's) it will also be necessary to save and restore
* the current sigaction's for the signals the child touches
* before it exec's.
*/
if (wanttty >= 0 && !nosigchld && !noexec) {
sigemptyset(&nsigset);
(void)sigaddset(&nsigset, SIGCHLD);
(void)sigprocmask(SIG_BLOCK, &nsigset, &csigset);
nosigchld = 1;
}
sigemptyset(&nsigset);
(void)sigaddset(&nsigset, SIGCHLD);
(void)sigaddset(&nsigset, SIGINT);
(void)sigprocmask(SIG_BLOCK, &nsigset, &osigset);
ochild = child;
osetintr = setintr;
ohaderr = haderr;
odidfds = didfds;
oSHIN = SHIN;
oSHOUT = SHOUT;
oSHERR = SHERR;
oOLDSTD = OLDSTD;
otpgrp = tpgrp;
ocsigset = csigset;
onosigchld = nosigchld;
Vsav = Vdp = 0;
Vexpath = 0;
Vt = 0;
pid = vfork();
if (pid < 0) {
(void)sigprocmask(SIG_SETMASK, &osigset, NULL);
stderror(ERR_NOPROC);
}
forked++;
if (pid) { /* parent */
child = ochild;
setintr = osetintr;
haderr = ohaderr;
didfds = odidfds;
SHIN = oSHIN;
SHOUT = oSHOUT;
SHERR = oSHERR;
OLDSTD = oOLDSTD;
tpgrp = otpgrp;
csigset = ocsigset;
nosigchld = onosigchld;
free(Vsav);
Vsav = 0;
free(Vdp);
Vdp = 0;
free(Vexpath);
Vexpath = 0;
blkfree((Char **)Vt);
Vt = 0;
/* this is from pfork() */
palloc(pid, t);
(void)sigprocmask(SIG_SETMASK, &osigset, NULL);
}
else { /* child */
/* this is from pfork() */
int pgrp;
int ignint = 0;
if (nosigchld) {
(void)sigprocmask(SIG_SETMASK, &csigset, NULL);
nosigchld = 0;
}
if (setintr)
ignint =
(tpgrp == -1 &&
(t->t_dflg & F_NOINTERRUPT))
|| (gointr && eq(gointr, STRminus));
pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
child++;
if (setintr) {
setintr = 0;
if (ignint) {
(void)signal(SIGINT, SIG_IGN);
(void)signal(SIGQUIT, SIG_IGN);
}
else {
(void)signal(SIGINT, vffree);
(void)signal(SIGQUIT, SIG_DFL);
}
if (wanttty >= 0) {
(void)signal(SIGTSTP, SIG_DFL);
(void)signal(SIGTTIN, SIG_DFL);
(void)signal(SIGTTOU, SIG_DFL);
}
(void)signal(SIGTERM, parterm);
}
else if (tpgrp == -1 &&
(t->t_dflg & F_NOINTERRUPT)) {
(void)signal(SIGINT, SIG_IGN);
(void)signal(SIGQUIT, SIG_IGN);
}
pgetty(wanttty, pgrp);
if (t->t_dflg & F_NOHUP)
(void)signal(SIGHUP, SIG_IGN);
if (t->t_dflg & F_NICE)
(void)setpriority(PRIO_PROCESS, 0, t->t_nice);
}
}
}
if (pid != 0) {
/*
* It would be better if we could wait for the whole job when we
* knew the last process had been started. Pwait, in fact, does
* wait for the whole job anyway, but this test doesn't really
* express our intentions.
*/
if (didfds == 0 && t->t_dflg & F_PIPEIN) {
(void)close(pipein[0]);
(void)close(pipein[1]);
}
if ((t->t_dflg & F_PIPEOUT) == 0) {
if (nosigchld) {
(void)sigprocmask(SIG_SETMASK, &csigset, NULL);
nosigchld = 0;
}
if ((t->t_dflg & F_AMPERSAND) == 0)
pwait();
}
break;
}
doio(t, pipein, pipeout);
if (t->t_dflg & F_PIPEOUT) {
(void)close(pipeout[0]);
(void)close(pipeout[1]);
}
/*
* Perform a builtin function. If we are not forked, arrange for
* possible stopping
*/
if (bifunc) {
func(t, bifunc);
if (forked)
exitstat();
break;
}
if (t->t_dtyp != NODE_PAREN)
doexec(NULL, t);
/*
* For () commands must put new 0,1,2 in FSH* and recurse
*/
(void) ioctl(OLDSTD = dcopy(0, FOLDSTD), FIOCLEX, NULL);
(void) ioctl(SHOUT = dcopy(1, FSHOUT), FIOCLEX, NULL);
(void) ioctl(SHERR = dcopy(2, FSHERR), FIOCLEX, NULL);
(void) close(SHIN);
SHIN = -1;
didfds = 0;
wanttty = -1;
t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT;
execute(t->t_dspr, wanttty, NULL, NULL);
exitstat();
/* NOTREACHED */
case NODE_PIPE:
t->t_dcar->t_dflg |= F_PIPEOUT |
(t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT));
execute(t->t_dcar, wanttty, pipein, pv);
t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
if (wanttty > 0)
wanttty = 0; /* got tty already */
execute(t->t_dcdr, wanttty, pv, pipeout);
break;
case NODE_LIST:
if (t->t_dcar) {
t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
execute(t->t_dcar, wanttty, NULL, NULL);
/*
* In strange case of A&B make a new job after A
*/
if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr &&
(t->t_dcdr->t_dflg & F_AMPERSAND) == 0)
pendjob();
}
if (t->t_dcdr) {
t->t_dcdr->t_dflg |= t->t_dflg &
(F_NOFORK | F_NOINTERRUPT);
execute(t->t_dcdr, wanttty, NULL, NULL);
}
break;
case NODE_OR:
case NODE_AND:
if (t->t_dcar) {
t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
execute(t->t_dcar, wanttty, NULL, NULL);
if ((getn(value(STRstatus)) == 0) !=
(t->t_dtyp == NODE_AND))
return;
}
if (t->t_dcdr) {
t->t_dcdr->t_dflg |= t->t_dflg &
(F_NOFORK | F_NOINTERRUPT);
execute(t->t_dcdr, wanttty, NULL, NULL);
}
break;
}
/*
* Fall through for all breaks from switch
*
* If there will be no more executions of this command, flush all file
* descriptors. Places that turn on the F_REPEAT bit are responsible for
* doing donefds after the last re-execution
*/
if (didfds && !(t->t_dflg & F_REPEAT))
donefds();
}
static void
vffree(int i)
{
Char **v;
if ((v = gargv) != NULL) {
gargv = 0;
free(v);
}
if ((v = pargv) != NULL) {
pargv = 0;
free(v);
}
_exit(i);
/* NOTREACHED */
}
/*
* Expand and glob the words after an i/o redirection.
* If more than one word is generated, then update the command vector.
*
* This is done differently in all the shells:
* 1. in the bourne shell and ksh globbing is not performed
* 2. Bash/csh say ambiguous
* 3. zsh does i/o to/from all the files
* 4. itcsh concatenates the words.
*
* I don't know what is best to do. I think that Ambiguous is better
* than restructuring the command vector, because the user can get
* unexpected results. In any case, the command vector restructuring
* code is present and the user can choose it by setting noambiguous
*/
static Char *
splicepipe(struct command *t, Char *cp /* word after < or > */)
{
Char *blk[2];
if (adrof(STRnoambiguous)) {
Char **pv;
blk[0] = Dfix1(cp); /* expand $ */
blk[1] = NULL;
gflag = 0, tglob(blk);
if (gflag) {
pv = globall(blk);
if (pv == NULL) {
setname(vis_str(blk[0]));
free(blk[0]);
stderror(ERR_NAME | ERR_NOMATCH);
/* NOTREACHED */
}
gargv = NULL;
if (pv[1] != NULL) { /* we need to fix the command vector */
Char **av = blkspl(t->t_dcom, &pv[1]);
free(t->t_dcom);
t->t_dcom = av;
}
free(blk[0]);
blk[0] = pv[0];
free(pv);
}
}
else {
blk[0] = globone(blk[1] = Dfix1(cp), G_ERROR);
free(blk[1]);
}
return(blk[0]);
}
/*
* Perform io redirection.
* We may or maynot be forked here.
*/
static void
doio(struct command *t, int *pipein, int *pipeout)
{
Char *cp;
int fd, flags;
flags = t->t_dflg;
if (didfds || (flags & F_REPEAT))
return;
if ((flags & F_READ) == 0) {/* F_READ already done */
if (t->t_dlef) {
char tmp[MAXPATHLEN+1];
/*
* so < /dev/std{in,out,err} work
*/
(void)dcopy(SHIN, 0);
(void)dcopy(SHOUT, 1);
(void)dcopy(SHERR, 2);
cp = splicepipe(t, t->t_dlef);
(void)strlcpy(tmp, short2str(cp), sizeof(tmp));
free(cp);
if ((fd = open(tmp, O_RDONLY)) < 0) {
stderror(ERR_SYSTEM, tmp, strerror(errno));
/* NOTREACHED */
}
(void)dmove(fd, 0);
}
else if (flags & F_PIPEIN) {
(void)close(0);
(void)dup(pipein[0]);
(void)close(pipein[0]);
(void)close(pipein[1]);
}
else if ((flags & F_NOINTERRUPT) && tpgrp == -1) {
(void)close(0);
(void)open(_PATH_DEVNULL, O_RDONLY);
}
else {
(void)close(0);
(void)dup(OLDSTD);
(void)ioctl(0, FIONCLEX, NULL);
}
}
if (t->t_drit) {
char tmp[MAXPATHLEN+1];
cp = splicepipe(t, t->t_drit);
(void)strlcpy(tmp, short2str(cp), sizeof(tmp));
free(cp);
/*
* so > /dev/std{out,err} work
*/
(void)dcopy(SHOUT, 1);
(void)dcopy(SHERR, 2);
if ((flags & F_APPEND) &&
#ifdef O_APPEND
(fd = open(tmp, O_WRONLY | O_APPEND)) >= 0);
#else
(fd = open(tmp, O_WRONLY)) >= 0)
(void)lseek(1, (off_t) 0, SEEK_END);
#endif
else {
if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) {
if (flags & F_APPEND) {
stderror(ERR_SYSTEM, tmp, strerror(errno));
/* NOTREACHED */
}
chkclob(tmp);
}
if ((fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0) {
stderror(ERR_SYSTEM, tmp, strerror(errno));
/* NOTREACHED */
}
}
(void)dmove(fd, 1);
}
else if (flags & F_PIPEOUT) {
(void)close(1);
(void)dup(pipeout[1]);
}
else {
(void)close(1);
(void)dup(SHOUT);
(void)ioctl(1, FIONCLEX, NULL);
}
(void)close(2);
if (flags & F_STDERR) {
(void)dup(1);
}
else {
(void)dup(SHERR);
(void)ioctl(2, FIONCLEX, NULL);
}
didfds = 1;
}
void
mypipe(int *pv)
{
if (pipe(pv) < 0)
goto oops;
pv[0] = dmove(pv[0], -1);
pv[1] = dmove(pv[1], -1);
if (pv[0] >= 0 && pv[1] >= 0)
return;
oops:
stderror(ERR_PIPE);
/* NOTREACHED */
}
static void
chkclob(char *cp)
{
struct stat stb;
if (stat(cp, &stb) < 0)
return;
if (S_ISCHR(stb.st_mode))
return;
stderror(ERR_EXISTS, cp);
/* NOTREACHED */
}
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