/*
* execute command tree
*/
int
execute(struct op * volatile t,
/* if XEXEC don't fork */
volatile int flags,
volatile int * volatile xerrok)
{
int i;
volatile int rv = 0, dummy = 0;
int pv[2];
const char ** volatile ap = NULL;
char ** volatile up;
const char *s, *ccp;
struct ioword **iowp;
struct tbl *tp = NULL;
char *cp;
if (t == NULL)
return (0);
/* Caller doesn't care if XERROK should propagate. */
if (xerrok == NULL)
xerrok = &dummy;
if ((flags&XFORK) && !(flags&XEXEC) && t->type != TPIPE)
/* run in sub-process */
return (exchild(t, flags & ~XTIME, xerrok, -1));
newenv(E_EXEC);
if (trap)
runtraps(0);
/* we want to run an executable, do some variance checks */
if (t->type == TCOM) {
/* check if this is 'var=<<EOF' */
if (
/* we have zero arguments, i.e. no programme to run */
t->args[0] == NULL &&
/* we have exactly one variable assignment */
t->vars[0] != NULL && t->vars[1] == NULL &&
/* we have exactly one I/O redirection */
t->ioact != NULL && t->ioact[0] != NULL &&
t->ioact[1] == NULL &&
/* of type "here document" (or "here string") */
(t->ioact[0]->flag & IOTYPE) == IOHERE &&
/* the variable assignment begins with a valid varname */
(ccp = skip_wdvarname(t->vars[0], true)) != t->vars[0] &&
/* and has no right-hand side (i.e. "varname=") */
ccp[0] == CHAR && ccp[1] == '=' && ccp[2] == EOS &&
/* plus we can have a here document content */
herein(t->ioact[0], &cp) == 0 && cp && *cp) {
char *sp = cp, *dp;
size_t n = ccp - t->vars[0] + 2, z;
/* drop redirection (will be garbage collected) */
t->ioact = NULL;
/* set variable to its expanded value */
z = strlen(cp) + 1;
if (notoktomul(z, 2) || notoktoadd(z * 2, n))
internal_errorf(Toomem, (unsigned long)-1);
dp = alloc(z * 2 + n, ATEMP);
memcpy(dp, t->vars[0], n);
t->vars[0] = dp;
dp += n;
while (*sp) {
*dp++ = QCHAR;
*dp++ = *sp++;
}
*dp = EOS;
/* free the expanded value */
afree(cp, APERM);
}
/*
* Clear subst_exstat before argument expansion. Used by
* null commands (see comexec() and c_eval()) and by c_set().
*/
subst_exstat = 0;
/* for $LINENO */
current_lineno = t->lineno;
/*
* POSIX says expand command words first, then redirections,
* and assignments last..
*/
up = eval(t->args, t->u.evalflags | DOBLANK | DOGLOB | DOTILDE);
if (flags & XTIME)
/* Allow option parsing (bizarre, but POSIX) */
timex_hook(t, &up);
ap = (const char **)up;
if (Flag(FXTRACE) && ap[0]) {
shf_puts(substitute(str_val(global("PS4")), 0),
shl_out);
for (i = 0; ap[i]; i++)
shf_fprintf(shl_out, "%s%c", ap[i],
ap[i + 1] ? ' ' : '\n');
shf_flush(shl_out);
}
if (ap[0])
tp = findcom(ap[0], FC_BI|FC_FUNC);
}
flags &= ~XTIME;
if (t->ioact != NULL || t->type == TPIPE || t->type == TCOPROC) {
e->savefd = alloc2(NUFILE, sizeof(short), ATEMP);
/* initialise to not redirected */
memset(e->savefd, 0, NUFILE * sizeof(short));
}
/* mark for replacement later (unless TPIPE) */
vp_pipest->flag |= INT_L;
/* do redirection, to be restored in quitenv() */
if (t->ioact != NULL)
for (iowp = t->ioact; *iowp != NULL; iowp++) {
if (iosetup(*iowp, tp) < 0) {
exstat = rv = 1;
/*
* Redirection failures for special commands
* cause (non-interactive) shell to exit.
*/
if (tp && tp->type == CSHELL &&
(tp->flag & SPEC_BI))
errorfz();
/* Deal with FERREXIT, quitenv(), etc. */
goto Break;
}
}
switch (t->type) {
case TCOM:
rv = comexec(t, tp, (const char **)ap, flags, xerrok);
break;
case TPAREN:
rv = execute(t->left, flags | XFORK, xerrok);
break;
case TPIPE:
flags |= XFORK;
flags &= ~XEXEC;
e->savefd[0] = savefd(0);
e->savefd[1] = savefd(1);
while (t->type == TPIPE) {
openpipe(pv);
/* stdout of curr */
ksh_dup2(pv[1], 1, false);
/**
* Let exchild() close pv[0] in child
* (if this isn't done, commands like
* (: ; cat /etc/termcap) | sleep 1
* will hang forever).
*/
exchild(t->left, flags | XPIPEO | XCCLOSE,
NULL, pv[0]);
/* stdin of next */
ksh_dup2(pv[0], 0, false);
closepipe(pv);
flags |= XPIPEI;
t = t->right;
}
/* stdout of last */
restfd(1, e->savefd[1]);
/* no need to re-restore this */
e->savefd[1] = 0;
/* Let exchild() close 0 in parent, after fork, before wait */
i = exchild(t, flags | XPCLOSE | XPIPEST, xerrok, 0);
if (!(flags&XBGND) && !(flags&XXCOM))
rv = i;
break;
case TLIST:
while (t->type == TLIST) {
execute(t->left, flags & XERROK, NULL);
t = t->right;
}
rv = execute(t, flags & XERROK, xerrok);
break;
case TCOPROC: {
#ifndef MKSH_NOPROSPECTOFWORK
sigset_t omask;
/*
* Block sigchild as we are using things changed in the
* signal handler
*/
sigprocmask(SIG_BLOCK, &sm_sigchld, &omask);
e->type = E_ERRH;
if ((i = kshsetjmp(e->jbuf))) {
sigprocmask(SIG_SETMASK, &omask, NULL);
quitenv(NULL);
unwind(i);
/* NOTREACHED */
}
#endif
/* Already have a (live) co-process? */
if (coproc.job && coproc.write >= 0)
errorf("coprocess already exists");
/* Can we re-use the existing co-process pipe? */
coproc_cleanup(true);
/* do this before opening pipes, in case these fail */
e->savefd[0] = savefd(0);
e->savefd[1] = savefd(1);
openpipe(pv);
if (pv[0] != 0) {
ksh_dup2(pv[0], 0, false);
close(pv[0]);
}
coproc.write = pv[1];
coproc.job = NULL;
if (coproc.readw >= 0)
ksh_dup2(coproc.readw, 1, false);
else {
openpipe(pv);
coproc.read = pv[0];
ksh_dup2(pv[1], 1, false);
/* closed before first read */
coproc.readw = pv[1];
coproc.njobs = 0;
/* create new coprocess id */
++coproc.id;
}
#ifndef MKSH_NOPROSPECTOFWORK
sigprocmask(SIG_SETMASK, &omask, NULL);
/* no more need for error handler */
e->type = E_EXEC;
#endif
/*
* exchild() closes coproc.* in child after fork,
* will also increment coproc.njobs when the
* job is actually created.
*/
flags &= ~XEXEC;
exchild(t->left, flags | XBGND | XFORK | XCOPROC | XCCLOSE,
NULL, coproc.readw);
break;
}
case TASYNC:
/*
* XXX non-optimal, I think - "(foo &)", forks for (),
* forks again for async... parent should optimise
* this to "foo &"...
*/
rv = execute(t->left, (flags&~XEXEC)|XBGND|XFORK, xerrok);
break;
case TOR:
case TAND:
rv = execute(t->left, XERROK, xerrok);
if ((rv == 0) == (t->type == TAND))
rv = execute(t->right, XERROK, xerrok);
flags |= XERROK;
if (xerrok)
*xerrok = 1;
break;
case TBANG:
rv = !execute(t->right, XERROK, xerrok);
flags |= XERROK;
if (xerrok)
*xerrok = 1;
break;
case TDBRACKET: {
Test_env te;
te.flags = TEF_DBRACKET;
te.pos.wp = t->args;
te.isa = dbteste_isa;
te.getopnd = dbteste_getopnd;
te.eval = test_eval;
te.error = dbteste_error;
rv = test_parse(&te);
break;
}
case TFOR:
case TSELECT: {
volatile bool is_first = true;
ap = (t->vars == NULL) ? e->loc->argv + 1 :
(const char **)eval((const char **)t->vars,
DOBLANK | DOGLOB | DOTILDE);
e->type = E_LOOP;
while ((i = kshsetjmp(e->jbuf))) {
if ((e->flags&EF_BRKCONT_PASS) ||
(i != LBREAK && i != LCONTIN)) {
quitenv(NULL);
unwind(i);
} else if (i == LBREAK) {
rv = 0;
goto Break;
}
}
/* in case of a continue */
rv = 0;
if (t->type == TFOR) {
while (*ap != NULL) {
setstr(global(t->str), *ap++, KSH_UNWIND_ERROR);
rv = execute(t->left, flags & XERROK, xerrok);
}
} else {
/* TSELECT */
for (;;) {
if (!(ccp = do_selectargs(ap, is_first))) {
rv = 1;
break;
}
is_first = false;
setstr(global(t->str), ccp, KSH_UNWIND_ERROR);
execute(t->left, flags & XERROK, xerrok);
}
}
break;
}
case TWHILE:
case TUNTIL:
e->type = E_LOOP;
while ((i = kshsetjmp(e->jbuf))) {
if ((e->flags&EF_BRKCONT_PASS) ||
(i != LBREAK && i != LCONTIN)) {
quitenv(NULL);
unwind(i);
} else if (i == LBREAK) {
rv = 0;
goto Break;
}
}
/* in case of a continue */
rv = 0;
while ((execute(t->left, XERROK, NULL) == 0) ==
(t->type == TWHILE))
rv = execute(t->right, flags & XERROK, xerrok);
break;
case TIF:
case TELIF:
if (t->right == NULL)
/* should be error */
break;
rv = execute(t->left, XERROK, NULL) == 0 ?
execute(t->right->left, flags & XERROK, xerrok) :
execute(t->right->right, flags & XERROK, xerrok);
break;
case TCASE:
i = 0;
ccp = evalstr(t->str, DOTILDE);
for (t = t->left; t != NULL && t->type == TPAT; t = t->right) {
for (ap = (const char **)t->vars; *ap; ap++) {
if (i || ((s = evalstr(*ap, DOTILDE|DOPAT)) &&
gmatchx(ccp, s, false))) {
rv = execute(t->left, flags & XERROK,
xerrok);
i = 0;
switch (t->u.charflag) {
case '&':
i = 1;
/* FALLTHROUGH */
case '|':
goto TCASE_next;
}
goto TCASE_out;
}
}
i = 0;
TCASE_next:
/* empty */;
}
TCASE_out:
break;
case TBRACE:
rv = execute(t->left, flags & XERROK, xerrok);
break;
case TFUNCT:
rv = define(t->str, t);
break;
case TTIME:
/*
* Clear XEXEC so nested execute() call doesn't exit
* (allows "ls -l | time grep foo").
*/
rv = timex(t, flags & ~XEXEC, xerrok);
break;
case TEXEC:
/* an eval'd TCOM */
s = t->args[0];
up = makenv();
restoresigs();
cleanup_proc_env();
{
union mksh_ccphack cargs;
cargs.ro = t->args;
execve(t->str, cargs.rw, up);
rv = errno;
}
if (rv == ENOEXEC)
scriptexec(t, (const char **)up);
else
errorf("%s: %s", s, cstrerror(rv));
}
Break:
exstat = rv & 0xFF;
if (vp_pipest->flag & INT_L) {
unset(vp_pipest, 1);
vp_pipest->flag = DEFINED | ISSET | INTEGER | RDONLY |
ARRAY | INT_U;
vp_pipest->val.i = rv;
}
/* restores IO */
quitenv(NULL);
if ((flags&XEXEC))
/* exit child */
unwind(LEXIT);
if (rv != 0 && !(flags & XERROK) &&
(xerrok == NULL || !*xerrok)) {
if (Flag(FERREXIT) & 0x80) {
/* inside eval */
Flag(FERREXIT) = 0;
} else {
trapsig(ksh_SIGERR);
if (Flag(FERREXIT))
unwind(LERROR);
}
}
return (rv);
}
char *
do_realpath(const char *upath)
{
char *xp, *ip, *tp, *ipath, *ldest = NULL;
XString xs;
size_t pos, len;
int llen;
struct stat sb;
#ifdef MKSH__NO_PATH_MAX
size_t ldestlen = 0;
#define pathlen sb.st_size
#define pathcnd (ldestlen < (pathlen + 1))
#else
#define pathlen PATH_MAX
#define pathcnd (!ldest)
#endif
/* max. recursion depth */
int symlinks = 32;
if (mksh_abspath(upath)) {
/* upath is an absolute pathname */
strdupx(ipath, upath, ATEMP);
} else {
/* upath is a relative pathname, prepend cwd */
if ((tp = ksh_get_wd()) == NULL || !mksh_abspath(tp))
return (NULL);
ipath = shf_smprintf("%s%s%s", tp, "/", upath);
afree(tp, ATEMP);
}
/* ipath and upath are in memory at the same time -> unchecked */
Xinit(xs, xp, strlen(ip = ipath) + 1, ATEMP);
/* now jump into the deep of the loop */
goto beginning_of_a_pathname;
while (*ip) {
/* skip slashes in input */
while (*ip == '/')
++ip;
if (!*ip)
break;
/* get next pathname component from input */
tp = ip;
while (*ip && *ip != '/')
++ip;
len = ip - tp;
/* check input for "." and ".." */
if (tp[0] == '.') {
if (len == 1)
/* just continue with the next one */
continue;
else if (len == 2 && tp[1] == '.') {
/* strip off last pathname component */
while (xp > Xstring(xs, xp))
if (*--xp == '/')
break;
/* then continue with the next one */
continue;
}
}
/* store output position away, then append slash to output */
pos = Xsavepos(xs, xp);
/* 1 for the '/' and len + 1 for tp and the NUL from below */
XcheckN(xs, xp, 1 + len + 1);
Xput(xs, xp, '/');
/* append next pathname component to output */
memcpy(xp, tp, len);
xp += len;
*xp = '\0';
/* lstat the current output, see if it's a symlink */
if (mksh_lstat(Xstring(xs, xp), &sb)) {
/* lstat failed */
if (errno == ENOENT) {
/* because the pathname does not exist */
while (*ip == '/')
/* skip any trailing slashes */
++ip;
/* no more components left? */
if (!*ip)
/* we can still return successfully */
break;
/* more components left? fall through */
}
/* not ENOENT or not at the end of ipath */
goto notfound;
}
/* check if we encountered a symlink? */
if (S_ISLNK(sb.st_mode)) {
#ifndef MKSH__NO_SYMLINK
/* reached maximum recursion depth? */
if (!symlinks--) {
/* yep, prevent infinite loops */
errno = ELOOP;
goto notfound;
}
/* get symlink(7) target */
if (pathcnd) {
#ifdef MKSH__NO_PATH_MAX
if (notoktoadd(pathlen, 1)) {
errno = ENAMETOOLONG;
goto notfound;
}
#endif
ldest = aresize(ldest, pathlen + 1, ATEMP);
}
llen = readlink(Xstring(xs, xp), ldest, pathlen);
if (llen < 0)
/* oops... */
goto notfound;
ldest[llen] = '\0';
/*
* restart if symlink target is an absolute path,
* otherwise continue with currently resolved prefix
*/
/* append rest of current input path to link target */
tp = shf_smprintf("%s%s%s", ldest, *ip ? "/" : "", ip);
afree(ipath, ATEMP);
ip = ipath = tp;
if (!mksh_abspath(ldest)) {
/* symlink target is a relative path */
xp = Xrestpos(xs, xp, pos);
} else
#endif
{
/* symlink target is an absolute path */
xp = Xstring(xs, xp);
beginning_of_a_pathname:
/* assert: (ip == ipath)[0] == '/' */
/* assert: xp == xs.beg => start of path */
/* exactly two leading slashes? (SUSv4 3.266) */
if (ip[1] == '/' && ip[2] != '/') {
/* keep them, e.g. for UNC pathnames */
Xput(xs, xp, '/');
}
}
}
/* otherwise (no symlink) merely go on */
}
/*
* either found the target and successfully resolved it,
* or found its parent directory and may create it
*/
if (Xlength(xs, xp) == 0)
/*
* if the resolved pathname is "", make it "/",
* otherwise do not add a trailing slash
*/
Xput(xs, xp, '/');
Xput(xs, xp, '\0');
/*
* if source path had a trailing slash, check if target path
* is not a non-directory existing file
*/
if (ip > ipath && ip[-1] == '/') {
if (stat(Xstring(xs, xp), &sb)) {
if (errno != ENOENT)
goto notfound;
} else if (!S_ISDIR(sb.st_mode)) {
errno = ENOTDIR;
goto notfound;
}
/* target now either does not exist or is a directory */
}
/* return target path */
if (ldest != NULL)
afree(ldest, ATEMP);
afree(ipath, ATEMP);
return (Xclose(xs, xp));
notfound:
/* save; freeing memory might trash it */
llen = errno;
if (ldest != NULL)
afree(ldest, ATEMP);
afree(ipath, ATEMP);
Xfree(xs, xp);
errno = llen;
return (NULL);
#undef pathlen
#undef pathcnd
}
