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cdesktopenv/src/cmd/ksh93/sh/subshell.c

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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1982-2012 AT&T Intellectual Property *
* Copyright (c) 2020-2021 Contributors to ksh 93u+m *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* David Korn <dgk@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Create and manage subshells avoiding forks when possible
*
* David Korn
* AT&T Labs
*
*/
#ifdef __linux__
#define _GNU_SOURCE /* needed for O_PATH */
#endif
#include "defs.h"
#include <ls.h>
#include "io.h"
#include "fault.h"
#include "shnodes.h"
#include "shlex.h"
#include "jobs.h"
#include "variables.h"
#include "path.h"
#ifndef PIPE_BUF
# define PIPE_BUF 512
#endif
#ifndef O_SEARCH
# ifdef O_PATH
# define O_SEARCH O_PATH
# else
# define O_SEARCH O_RDONLY
# endif
#endif
/*
* Note that the following structure must be the same
* size as the Dtlink_t structure
*/
struct Link
{
struct Link *next;
Namval_t *child;
Dt_t *dict;
Namval_t *node;
};
/*
* The following structure is used for command substitution and (...)
*/
static struct subshell
{
Shell_t *shp; /* shell interpreter */
struct subshell *prev; /* previous subshell data */
struct subshell *pipe; /* subshell where output goes to pipe on fork */
Dt_t *var; /* variable table at time of subshell */
struct Link *svar; /* save shell variable table */
Dt_t *sfun; /* function scope for subshell */
Dt_t *strack;/* tracked alias scope for subshell */
Pathcomp_t *pathlist; /* for PATH variable */
struct Error_context_s *errcontext;
Shopt_t options;/* save shell options */
pid_t subpid; /* child process id */
Sfio_t* saveout;/* saved standard output */
char *pwd; /* present working directory */
void *jobs; /* save job info */
mode_t mask; /* saved umask */
short tmpfd; /* saved tmp file descriptor */
short pipefd; /* read fd if pipe is created */
char jobcontrol;
char monitor;
unsigned char fdstatus;
int fdsaved; /* bit mask for saved file descriptors */
int sig; /* signal for $$ */
pid_t bckpid;
pid_t cpid;
int coutpipe;
int cpipe;
int nofork;
int subdup;
char subshare;
char comsub;
unsigned int rand_seed; /* parent shell $RANDOM seed */
int rand_last; /* last random number from $RANDOM in parent shell */
int rand_state; /* 0 means sp->rand_seed hasn't been set, 1 is the opposite */
#if _lib_fchdir
int pwdfd; /* file descriptor for PWD */
char pwdclose;
#endif /* _lib_fchdir */
} *subshell_data;
static char subshell_noscope; /* for temporarily disabling all virtual subshell scope creation */
static unsigned int subenv;
/*
* This routine will turn the sftmp() file into a real temporary file
*/
void sh_subtmpfile(Shell_t *shp)
{
if(sfset(sfstdout,0,0)&SF_STRING)
{
register int fd;
register struct checkpt *pp = (struct checkpt*)shp->jmplist;
register struct subshell *sp = subshell_data->pipe;
/* save file descriptor 1 if open */
if((sp->tmpfd = fd = sh_fcntl(1,F_DUPFD,10)) >= 0)
{
fcntl(fd,F_SETFD,FD_CLOEXEC);
shp->fdstatus[fd] = shp->fdstatus[1]|IOCLEX;
close(1);
}
else if(errno!=EBADF)
{
errormsg(SH_DICT,ERROR_system(1),e_toomany);
UNREACHABLE();
}
/* popping a discipline forces a /tmp file create */
sfdisc(sfstdout,SF_POPDISC);
if((fd=sffileno(sfstdout))<0)
{
errormsg(SH_DICT,ERROR_SYSTEM|ERROR_PANIC,"could not create temp file");
UNREACHABLE();
}
shp->fdstatus[fd] = IOREAD|IOWRITE;
sfsync(sfstdout);
if(fd==1)
fcntl(1,F_SETFD,0);
else
{
sfsetfd(sfstdout,1);
shp->fdstatus[1] = shp->fdstatus[fd];
shp->fdstatus[fd] = IOCLOSE;
}
sh_iostream(shp,1);
sfset(sfstdout,SF_SHARE|SF_PUBLIC,1);
sfpool(sfstdout,shp->outpool,SF_WRITE);
if(pp && pp->olist && pp->olist->strm == sfstdout)
pp->olist->strm = 0;
}
}
/*
* This routine creates a temp file if necessary, then forks a virtual subshell into a real subshell.
* The parent routine longjmps back to sh_subshell()
* The child continues possibly with its standard output replaced by temp file
*/
void sh_subfork(void)
{
register struct subshell *sp = subshell_data;
Shell_t *shp = sp->shp;
unsigned int curenv = shp->curenv;
char comsub = shp->comsub;
pid_t pid;
char *trap = shp->st.trapcom[0];
if(trap)
trap = sh_strdup(trap);
/* see whether inside $(...) */
if(sp->pipe)
sh_subtmpfile(shp);
shp->curenv = 0;
shp->savesig = -1;
if(pid = sh_fork(shp,FSHOWME,NIL(int*)))
{
shp->curenv = curenv;
/* this is the parent part of the fork */
if(sp->subpid==0)
sp->subpid = pid;
if(trap)
free((void*)trap);
siglongjmp(*shp->jmplist,SH_JMPSUB);
}
else
{
/* this is the child part of the fork */
sh_onstate(SH_FORKED);
/*
* $RANDOM is only reseeded when it's used in a subshell, so if $RANDOM hasn't
* been reseeded yet set rp->rand_last to -2. This allows sh_save_rand_seed()
* to reseed $RANDOM later.
*/
if(!sp->rand_state)
{
struct rand *rp;
rp = (struct rand*)RANDNOD->nvfun;
rp->rand_last = -2;
}
subshell_data = 0;
shp->subshell = 0;
shp->comsub = 0;
sp->subpid=0;
shp->st.trapcom[0] = (comsub==2 ? NIL(char*) : trap);
shp->savesig = 0;
/* sh_fork() increases ${.sh.subshell} but we forked an existing virtual subshell, so undo */
shgd->realsubshell--;
}
}
int nv_subsaved(register Namval_t *np, int flags)
{
register struct subshell *sp;
register struct Link *lp, *lpprev;
for(sp = (struct subshell*)subshell_data; sp; sp=sp->prev)
{
lpprev = 0;
for(lp=sp->svar; lp; lpprev=lp, lp=lp->next)
{
if(lp->node==np)
{
if(flags&NV_TABLE)
{
if(lpprev)
lpprev->next = lp->next;
else
sp->svar = lp->next;
free((void*)np);
free((void*)lp);
}
return(1);
}
}
}
return(0);
}
/*
* Save the current $RANDOM seed and state, then reseed $RANDOM.
*/
void sh_save_rand_seed(struct rand *rp, int reseed)
{
struct subshell *sp = subshell_data;
if(!sh.subshare && sp && !sp->rand_state)
{
sp->rand_seed = rp->rand_seed;
sp->rand_last = rp->rand_last;
sp->rand_state = 1;
if(reseed)
sh_reseed_rand(rp);
}
else if(reseed && rp->rand_last == -2)
sh_reseed_rand(rp);
}
/*
* This routine will make a copy of the given node in the
* layer created by the most recent virtual subshell if the
* node hasn't already been copied.
*
* add == 0: Move the node pointer from the parent shell to the current virtual subshell.
* add == 1: Create a copy of the node pointer in the current virtual subshell.
* add == 2: This will create a copy of the node pointer like 1, but it will disable the
* optimization for ${.sh.level}.
*/
Namval_t *sh_assignok(register Namval_t *np,int add)
{
register Namval_t *mp;
register struct Link *lp;
struct subshell *sp = subshell_data;
Shell_t *shp = sp->shp;
Dt_t *dp= shp->var_tree;
Namval_t *mpnext;
Namarr_t *ap;
unsigned int save;
/*
* Don't create a scope if told not to (see nv_restore()) or if this is a subshare.
* Also, moving/copying ${.sh.level} (SH_LEVELNOD) may crash the shell.
*/
if(subshell_noscope || sh.subshare || add<2 && np==SH_LEVELNOD)
return(np);
if((ap=nv_arrayptr(np)) && (mp=nv_opensub(np)))
{
shp->last_root = ap->table;
sh_assignok(mp,add);
if(!add || array_assoc(ap))
return(np);
}
for(lp=sp->svar; lp;lp = lp->next)
{
if(lp->node==np)
return(np);
}
/* first two pointers use linkage from np */
lp = (struct Link*)sh_malloc(sizeof(*np)+2*sizeof(void*));
memset(lp,0, sizeof(*mp)+2*sizeof(void*));
lp->node = np;
if(!add && nv_isvtree(np))
{
Namval_t fake;
Dt_t *walk, *root=shp->var_tree;
char *name = nv_name(np);
size_t len = strlen(name);
fake.nvname = name;
mpnext = dtnext(root,&fake);
dp = root->walk?root->walk:root;
while(mp=mpnext)
{
walk = root->walk?root->walk:root;
mpnext = dtnext(root,mp);
if(strncmp(name,mp->nvname,len) || mp->nvname[len]!='.')
break;
nv_delete(mp,walk,NV_NOFREE);
*((Namval_t**)mp) = lp->child;
lp->child = mp;
}
}
lp->dict = dp;
mp = (Namval_t*)&lp->dict;
lp->next = subshell_data->svar;
subshell_data->svar = lp;
save = shp->subshell;
shp->subshell = 0;
mp->nvname = np->nvname;
if(nv_isattr(np,NV_NOFREE))
nv_onattr(mp,NV_IDENT);
nv_clone(np,mp,(add?(nv_isnull(np)?0:NV_NOFREE)|NV_ARRAY:NV_MOVE));
shp->subshell = save;
return(np);
}
/*
* restore the variables
*/
static void nv_restore(struct subshell *sp)
{
register struct Link *lp, *lq;
register Namval_t *mp, *np;
Namval_t *mpnext;
int flags,nofree;
subshell_noscope = 1;
for(lp=sp->svar; lp; lp=lq)
{
np = (Namval_t*)&lp->dict;
lq = lp->next;
mp = lp->node;
if(!mp->nvname)
continue;
flags = 0;
if(nv_isattr(mp,NV_MINIMAL) && !nv_isattr(np,NV_EXPORT))
flags |= NV_MINIMAL;
if(nv_isarray(mp))
nv_putsub(mp,NIL(char*),ARRAY_SCAN);
nofree = mp->nvfun?mp->nvfun->nofree:0;
_nv_unset(mp,NV_RDONLY|NV_CLONE);
if(nv_isarray(np))
{
nv_clone(np,mp,NV_MOVE);
goto skip;
}
nv_setsize(mp,nv_size(np));
if(!(flags&NV_MINIMAL))
mp->nvenv = np->nvenv;
mp->nvfun = np->nvfun;
if(np->nvfun && nofree)
np->nvfun->nofree = nofree;
if(nv_isattr(np,NV_IDENT))
{
nv_offattr(np,NV_IDENT);
flags |= NV_NOFREE;
}
mp->nvflag = np->nvflag|(flags&NV_MINIMAL);
if(nv_cover(mp))
nv_putval(mp,nv_getval(np),NV_RDONLY);
else
mp->nvalue = np->nvalue;
if(nofree && np->nvfun && !np->nvfun->nofree)
free((char*)np->nvfun);
np->nvfun = 0;
if(nv_isattr(mp,NV_EXPORT))
{
char *name = nv_name(mp);
sh_envput(sp->shp->env,mp);
if(*name=='_' && strcmp(name,"_AST_FEATURES")==0)
astconf(NiL, NiL, NiL);
}
else if(nv_isattr(np,NV_EXPORT))
env_delete(sp->shp->env,nv_name(mp));
nv_onattr(mp,flags);
skip:
for(mp=lp->child; mp; mp=mpnext)
{
mpnext = *((Namval_t**)mp);
dtinsert(lp->dict,mp);
}
free((void*)lp);
sp->svar = lq;
}
subshell_noscope = 0;
}
/*
* Return pointer to tracked alias tree (a.k.a. hash table, i.e. cached $PATH search results).
* Create new one if in a subshell and one doesn't exist and 'create' is non-zero.
*/
Dt_t *sh_subtracktree(int create)
{
register struct subshell *sp = subshell_data;
if(create && sh.subshell && !sh.subshare)
{
if(sp && !sp->strack)
{
sp->strack = dtopen(&_Nvdisc,Dtset);
dtuserdata(sp->strack,&sh,1);
dtview(sp->strack,sh.track_tree);
sh.track_tree = sp->strack;
}
}
return(sh.track_tree);
}
/*
* return pointer to function tree
* create new one if in a subshell and one doesn't exist and create is non-zero
*/
Dt_t *sh_subfuntree(int create)
{
register struct subshell *sp = subshell_data;
if(create && sh.subshell && !sh.subshare)
{
if(sp && !sp->sfun)
{
sp->sfun = dtopen(&_Nvdisc,Dtoset);
dtuserdata(sp->sfun,&sh,1);
dtview(sp->sfun,sh.fun_tree);
sh.fun_tree = sp->sfun;
}
}
return(sh.fun_tree);
}
int sh_subsavefd(register int fd)
{
register struct subshell *sp = subshell_data;
register int old=0;
if(sp)
{
old = !(sp->fdsaved&(1<<fd));
sp->fdsaved |= (1<<fd);
}
return(old);
}
void sh_subjobcheck(pid_t pid)
{
register struct subshell *sp = subshell_data;
while(sp)
{
if(sp->cpid==pid)
{
sh_close(sp->coutpipe);
sh_close(sp->cpipe);
sp->coutpipe = sp->cpipe = -1;
return;
}
sp = sp->prev;
}
}
/*
* Run command tree <t> in a virtual subshell
* If comsub is not null, then output will be placed in temp file (or buffer)
* If comsub is not null, the return value will be a stream consisting of
* output of command <t>. Otherwise, NULL will be returned.
*/
Sfio_t *sh_subshell(Shell_t *shp,Shnode_t *t, volatile int flags, int comsub)
{
struct subshell sub_data;
register struct subshell *sp = &sub_data;
int jmpval,isig,nsig=0,fatalerror=0,saveerrno=0;
unsigned int savecurenv = shp->curenv;
int savejobpgid = job.curpgid;
int *saveexitval = job.exitval;
char **savsig;
Sfio_t *iop=0;
struct checkpt buff;
struct sh_scoped savst;
struct dolnod *argsav=0;
int argcnt;
memset((char*)sp, 0, sizeof(*sp));
sfsync(shp->outpool);
sh_sigcheck(shp);
shp->savesig = -1;
if(argsav = sh_arguse(shp))
argcnt = argsav->dolrefcnt;
if(shp->curenv==0)
{
subshell_data=0;
subenv = 0;
}
shp->curenv = ++subenv;
savst = shp->st;
sh_pushcontext(shp,&buff,SH_JMPSUB);
shp->subshell++; /* increase level of virtual subshells */
shgd->realsubshell++; /* increase ${.sh.subshell} */
sp->prev = subshell_data;
sp->shp = shp;
sp->sig = 0;
subshell_data = sp;
sp->errcontext = &buff.err;
sp->var = shp->var_tree;
sp->options = shp->options;
sp->jobs = job_subsave();
sp->subdup = shp->subdup;
shp->subdup = 0;
/* make sure initialization has occurred */
if(!shp->pathlist)
{
shp->pathinit = 1;
path_get(shp,e_dot);
shp->pathinit = 0;
}
if(!shp->pwd)
path_pwd(shp,0);
sp->bckpid = shp->bckpid;
if(comsub)
sh_stats(STAT_COMSUB);
else
job.curpgid = 0;
sp->subshare = shp->subshare;
sp->comsub = shp->comsub;
shp->subshare = comsub==2;
if(!shp->subshare)
sp->pathlist = path_dup((Pathcomp_t*)shp->pathlist);
if(comsub)
shp->comsub = comsub;
if(!shp->subshare)
{
struct subshell *xp;
#if _lib_fchdir
sp->pwdfd = -1;
for(xp=sp->prev; xp; xp=xp->prev)
{
if(xp->pwdfd>0 && xp->pwd && strcmp(xp->pwd,shp->pwd)==0)
{
sp->pwdfd = xp->pwdfd;
break;
}
}
if(sp->pwdfd<0)
{
int n = open(e_dot,O_SEARCH);
if(n>=0)
{
sp->pwdfd = n;
if(n<10)
{
sp->pwdfd = sh_fcntl(n,F_DUPFD,10);
close(n);
}
if(sp->pwdfd>0)
{
fcntl(sp->pwdfd,F_SETFD,FD_CLOEXEC);
sp->pwdclose = 1;
}
}
}
#endif /* _lib_fchdir */
sp->pwd = (shp->pwd?sh_strdup(shp->pwd):0);
sp->mask = shp->mask;
sh_stats(STAT_SUBSHELL);
/* save trap table */
shp->st.otrapcom = 0;
shp->st.otrap = savst.trap;
if((nsig=shp->st.trapmax)>0 || shp->st.trapcom[0])
{
savsig = sh_malloc(nsig * sizeof(char*));
/*
* the data is, usually, modified in code like:
* tmp = buf[i]; buf[i] = sh_strdup(tmp); free(tmp);
* so shp->st.trapcom needs a "deep copy" to properly save/restore pointers.
*/
for (isig = 0; isig < nsig; ++isig)
{
if(shp->st.trapcom[isig] == Empty)
savsig[isig] = Empty;
else if(shp->st.trapcom[isig])
savsig[isig] = sh_strdup(shp->st.trapcom[isig]);
else
savsig[isig] = NIL(char*);
}
/* this is needed for var=$(trap) */
shp->st.otrapcom = (char**)savsig;
}
sp->cpid = shp->cpid;
sp->coutpipe = shp->coutpipe;
sp->cpipe = shp->cpipe[1];
shp->cpid = 0;
sh_sigreset(0);
}
jmpval = sigsetjmp(buff.buff,0);
if(jmpval==0)
{
if(comsub)
{
/* disable job control */
shp->spid = 0;
sp->jobcontrol = job.jobcontrol;
sp->monitor = (sh_isstate(SH_MONITOR)!=0);
job.jobcontrol=0;
sh_offstate(SH_MONITOR);
sp->pipe = sp;
/* save sfstdout and status */
sp->saveout = sfswap(sfstdout,NIL(Sfio_t*));
sp->fdstatus = shp->fdstatus[1];
sp->tmpfd = -1;
sp->pipefd = -1;
/* use sftmp() file for standard output */
if(!(iop = sftmp(PIPE_BUF)))
{
sfswap(sp->saveout,sfstdout);
errormsg(SH_DICT,ERROR_system(1),e_tmpcreate);
UNREACHABLE();
}
sfswap(iop,sfstdout);
sfset(sfstdout,SF_READ,0);
shp->fdstatus[1] = IOWRITE;
if(!(sp->nofork = sh_state(SH_NOFORK)))
sh_onstate(SH_NOFORK);
flags |= sh_state(SH_NOFORK);
}
else if(sp->prev)
{
sp->pipe = sp->prev->pipe;
flags &= ~sh_state(SH_NOFORK);
}
if(shp->savesig < 0)
{
shp->savesig = 0;
#if _lib_fchdir
if(sp->pwdfd < 0 && !shp->subshare) /* if we couldn't get a file descriptor to our PWD ... */
sh_subfork(); /* ...we have to fork, as we cannot fchdir back to it. */
#else
if(!shp->subshare)
{
if(sp->pwd && access(sp->pwd,X_OK)<0)
{
free(sp->pwd);
sp->pwd = NIL(char*);
}
if(!sp->pwd)
sh_subfork();
}
#endif /* _lib_fchdir */
sh_offstate(SH_INTERACTIVE);
sh_exec(t,flags);
}
}
if(comsub!=2 && jmpval!=SH_JMPSUB && shp->st.trapcom[0] && shp->subshell)
{
/* trap on EXIT not handled by child */
char *trap=shp->st.trapcom[0];
shp->st.trapcom[0] = 0; /* prevent recursion */
sh_trap(trap,0);
free(trap);
}
sh_popcontext(shp,&buff);
if(shp->subshell==0) /* must be child process */
{
subshell_data = sp->prev;
if(jmpval==SH_JMPSCRIPT)
siglongjmp(*shp->jmplist,jmpval);
shp->exitval &= SH_EXITMASK;
sh_done(shp,0);
}
if(!shp->savesig)
shp->savesig = -1;
nv_restore(sp);
if(comsub)
{
/* re-enable job control */
if(!sp->nofork)
sh_offstate(SH_NOFORK);
job.jobcontrol = sp->jobcontrol;
if(sp->monitor)
sh_onstate(SH_MONITOR);
if(sp->pipefd>=0)
{
/* sftmp() file has been returned into pipe */
iop = sh_iostream(shp,sp->pipefd);
sfclose(sfstdout);
}
else
{
if(shp->spid)
{
int e = shp->exitval;
job_wait(shp->spid);
shp->exitval = e;
if(shp->pipepid==shp->spid)
shp->spid = 0;
shp->pipepid = 0;
}
/* move tmp file to iop and restore sfstdout */
iop = sfswap(sfstdout,NIL(Sfio_t*));
if(!iop)
{
/* maybe locked try again */
sfclrlock(sfstdout);
iop = sfswap(sfstdout,NIL(Sfio_t*));
}
if(iop && sffileno(iop)==1)
{
int fd = sfsetfd(iop,sh_iosafefd(shp,3));
if(fd<0)
{
shp->toomany = 1;
((struct checkpt*)shp->jmplist)->mode = SH_JMPERREXIT;
errormsg(SH_DICT,ERROR_system(1),e_toomany);
UNREACHABLE();
}
if(fd >= shp->gd->lim.open_max)
sh_iovalidfd(shp,fd);
shp->sftable[fd] = iop;
fcntl(fd,F_SETFD,FD_CLOEXEC);
shp->fdstatus[fd] = (shp->fdstatus[1]|IOCLEX);
shp->fdstatus[1] = IOCLOSE;
}
sfset(iop,SF_READ,1);
}
if(sp->saveout)
sfswap(sp->saveout,sfstdout);
else
sfstdout = &_Sfstdout;
/* check if standard output was preserved */
if(sp->tmpfd>=0)
{
int err=errno;
while(close(1)<0 && errno==EINTR)
errno = err;
if (fcntl(sp->tmpfd,F_DUPFD,1) != 1)
{
saveerrno = errno;
fatalerror = 1;
}
sh_close(sp->tmpfd);
}
shp->fdstatus[1] = sp->fdstatus;
}
if(!shp->subshare)
{
path_delete((Pathcomp_t*)shp->pathlist);
shp->pathlist = (void*)sp->pathlist;
}
job_subrestore(sp->jobs);
shp->curenv = shp->jobenv = savecurenv;
job.curpgid = savejobpgid;
job.exitval = saveexitval;
shp->bckpid = sp->bckpid;
if(!shp->subshare) /* restore environment if saved */
{
int n;
struct rand *rp;
shp->options = sp->options;
/* Clean up subshell hash table. */
if(sp->strack)
{
Namval_t *np, *next_np;
/* Detach this scope from the unified view. */
shp->track_tree = dtview(sp->strack,0);
/* Free all elements of the subshell hash table. */
for(np = (Namval_t*)dtfirst(sp->strack); np; np = next_np)
{
next_np = (Namval_t*)dtnext(sp->strack,np);
nv_delete(np,sp->strack,0);
}
/* Close and free the table itself. */
dtclose(sp->strack);
}
/* Clean up subshell function table. */
if(sp->sfun)
{
Namval_t *np, *next_np;
/* Detach this scope from the unified view. */
shp->fun_tree = dtview(sp->sfun,0);
/* Free all elements of the subshell function table. */
for(np = (Namval_t*)dtfirst(sp->sfun); np; np = next_np)
{
next_np = (Namval_t*)dtnext(sp->sfun,np);
if(!np->nvalue.rp)
{
/* Dummy node created by unall() to mask parent shell function. */
nv_delete(np,sp->sfun,0);
continue;
}
nv_onattr(np,NV_FUNCTION); /* in case invalidated by unall() */
if(np->nvalue.rp->fname && shp->fpathdict && nv_search(np->nvalue.rp->fname,shp->fpathdict,0))
{
/* Autoloaded function. It must not be freed. */
np->nvalue.rp->fdict = 0;
nv_delete(np,sp->sfun,NV_FUNCTION|NV_NOFREE);
}
else
{
_nv_unset(np,NV_RDONLY);
nv_delete(np,sp->sfun,NV_FUNCTION);
}
}
dtclose(sp->sfun);
}
n = shp->st.trapmax-savst.trapmax;
sh_sigreset(1);
if(n>0)
memset(&shp->st.trapcom[savst.trapmax],0,n*sizeof(char*));
shp->st = savst;
shp->st.otrap = 0;
if(nsig)
{
for (isig = 0; isig < nsig; ++isig)
if (shp->st.trapcom[isig] && shp->st.trapcom[isig]!=Empty)
free(shp->st.trapcom[isig]);
memcpy((char*)&shp->st.trapcom[0],savsig,nsig*sizeof(char*));
free((void*)savsig);
}
shp->options = sp->options;
/* restore the present working directory */
#if _lib_fchdir
if(sp->pwdfd > 0 && fchdir(sp->pwdfd) < 0)
#else
if(sp->pwd && strcmp(sp->pwd,shp->pwd) && chdir(sp->pwd) < 0)
#endif /* _lib_fchdir */
{
saveerrno = errno;
fatalerror = 2;
}
else if(sp->pwd && strcmp(sp->pwd,shp->pwd))
path_newdir(shp,shp->pathlist);
if(shp->pwd)
free((void*)shp->pwd);
shp->pwd = sp->pwd;
#if _lib_fchdir
if(sp->pwdclose)
close(sp->pwdfd);
#endif /* _lib_fchdir */
if(sp->mask!=shp->mask)
umask(shp->mask=sp->mask);
if(shp->coutpipe!=sp->coutpipe)
{
sh_close(shp->coutpipe);
sh_close(shp->cpipe[1]);
}
shp->cpid = sp->cpid;
shp->cpipe[1] = sp->cpipe;
shp->coutpipe = sp->coutpipe;
/* restore $RANDOM seed and state */
rp = (struct rand*)RANDNOD->nvfun;
if(sp->rand_state)
{
srand(rp->rand_seed = sp->rand_seed);
rp->rand_last = sp->rand_last;
}
/* Real subshells have their exit status truncated to 8 bits by the kernel.
* Since virtual subshells should be indistinguishable, do the same here. */
sh.exitval &= SH_EXITMASK;
}
shp->subshare = sp->subshare;
shp->subdup = sp->subdup;
if(shp->subshell)
{
shp->subshell--; /* decrease level of virtual subshells */
shgd->realsubshell--; /* decrease ${.sh.subshell} */
}
subshell_data = sp->prev;
if(!argsav || argsav->dolrefcnt==argcnt)
sh_argfree(shp,argsav,0);
if(shp->topfd != buff.topfd)
sh_iorestore(shp,buff.topfd|IOSUBSHELL,jmpval);
if(sp->sig)
{
if(sp->prev)
sp->prev->sig = sp->sig;
else
{
kill(shgd->current_pid,sp->sig);
sh_chktrap(shp);
}
}
sh_sigcheck(shp);
shp->trapnote = 0;
nsig = shp->savesig;
shp->savesig = 0;
if(nsig>0)
kill(shgd->current_pid,nsig);
if(sp->subpid)
{
job_wait(sp->subpid);
if(comsub)
sh_iounpipe(shp);
}
shp->comsub = sp->comsub;
if(comsub && iop && sp->pipefd<0)
sfseek(iop,(off_t)0,SEEK_SET);
if(shp->trapnote)
sh_chktrap(shp);
if(shp->exitval > SH_EXITSIG)
{
int sig = shp->exitval&SH_EXITMASK;
if(sig==SIGINT || sig== SIGQUIT)
kill(shgd->current_pid,sig);
}
if(fatalerror)
{
((struct checkpt*)shp->jmplist)->mode = SH_JMPERREXIT;
switch(fatalerror)
{
case 1:
shp->toomany = 1;
errno = saveerrno;
errormsg(SH_DICT,ERROR_SYSTEM|ERROR_PANIC,e_redirect);
UNREACHABLE();
case 2:
/* reinit PWD as it will be wrong */
if(shp->pwd)
free((void*)shp->pwd);
shp->pwd = NIL(const char*);
path_pwd(shp,0);
errno = saveerrno;
errormsg(SH_DICT,ERROR_SYSTEM|ERROR_PANIC,"Failed to restore PWD upon exiting subshell");
UNREACHABLE();
default:
errormsg(SH_DICT,ERROR_SYSTEM|ERROR_PANIC,"Subshell error %d",fatalerror);
UNREACHABLE();
}
}
if(shp->ignsig)
kill(shgd->current_pid,shp->ignsig);
if(jmpval==SH_JMPSUB && shp->lastsig)
kill(shgd->current_pid,shp->lastsig);
if(jmpval && shp->toomany)
siglongjmp(*shp->jmplist,jmpval);
return(iop);
}
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