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src/bin/ksh/eval.c

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/* $OpenBSD: eval.c,v 1.67 2023/05/24 14:20:33 millert Exp $ */
/*
* Expansion - quoting, separation, substitution, globbing
*/
#include <sys/stat.h>
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "sh.h"
/*
* string expansion
*
* first pass: quoting, IFS separation, ~, ${}, $() and $(()) substitution.
* second pass: alternation ({,}), filename expansion (*?[]).
*/
/* expansion generator state */
typedef struct Expand {
/* int type; */ /* see expand() */
const char *str; /* string */
union {
const char **strv;/* string[] */
struct shf *shf;/* file */
} u; /* source */
struct tbl *var; /* variable in ${var..} */
short split; /* split "$@" / call waitlast $() */
} Expand;
#define XBASE 0 /* scanning original */
#define XSUB 1 /* expanding ${} string */
#define XARGSEP 2 /* ifs0 between "$*" */
#define XARG 3 /* expanding $*, $@ */
#define XCOM 4 /* expanding $() */
#define XNULLSUB 5 /* "$@" when $# is 0 (don't generate word) */
#define XSUBMID 6 /* middle of expanding ${} */
/* States used for field splitting */
#define IFS_WORD 0 /* word has chars (or quotes) */
#define IFS_WS 1 /* have seen IFS white-space */
#define IFS_NWS 2 /* have seen IFS non-white-space */
#define IFS_IWS 3 /* beginning of word, ignore IFS white-space */
#define IFS_QUOTE 4 /* beg.w/quote, becomes IFS_WORD unless "$@" */
static int varsub(Expand *, char *, char *, int *, int *);
static int comsub(Expand *, char *);
static char *trimsub(char *, char *, int);
static void glob(char *, XPtrV *, int);
static void globit(XString *, char **, char *, XPtrV *, int);
static char *maybe_expand_tilde(char *, XString *, char **, int);
static char *tilde(char *);
static char *homedir(char *);
static void alt_expand(XPtrV *, char *, char *, char *, int);
static struct tbl *varcpy(struct tbl *);
/* compile and expand word */
char *
substitute(const char *cp, int f)
{
struct source *s, *sold;
if (disable_subst)
return str_save(cp, ATEMP);
sold = source;
s = pushs(SWSTR, ATEMP);
s->start = s->str = cp;
source = s;
if (yylex(ONEWORD) != LWORD)
internal_errorf("substitute");
source = sold;
afree(s, ATEMP);
return evalstr(yylval.cp, f);
}
/*
* expand arg-list
*/
char **
eval(char **ap, int f)
{
XPtrV w;
if (*ap == NULL)
return ap;
XPinit(w, 32);
XPput(w, NULL); /* space for shell name */
while (*ap != NULL)
expand(*ap++, &w, f);
XPput(w, NULL);
return (char **) XPclose(w) + 1;
}
/*
* expand string
*/
char *
evalstr(char *cp, int f)
{
XPtrV w;
XPinit(w, 1);
expand(cp, &w, f);
cp = (XPsize(w) == 0) ? null : (char*) *XPptrv(w);
XPfree(w);
return cp;
}
/*
* expand string - return only one component
* used from iosetup to expand redirection files
*/
char *
evalonestr(char *cp, int f)
{
XPtrV w;
XPinit(w, 1);
expand(cp, &w, f);
switch (XPsize(w)) {
case 0:
cp = null;
break;
case 1:
cp = (char*) *XPptrv(w);
break;
default:
cp = evalstr(cp, f&~DOGLOB);
break;
}
XPfree(w);
return cp;
}
/* for nested substitution: ${var:=$var2} */
typedef struct SubType {
short stype; /* [=+-?%#] action after expanded word */
short base; /* begin position of expanded word */
short f; /* saved value of f (DOPAT, etc) */
struct tbl *var; /* variable for ${var..} */
short quote; /* saved value of quote (for ${..[%#]..}) */
struct SubType *prev; /* old type */
struct SubType *next; /* poped type (to avoid re-allocating) */
} SubType;
void
expand(char *cp, /* input word */
XPtrV *wp, /* output words */
int f) /* DO* flags */
{
int c = 0;
int type; /* expansion type */
int quote = 0; /* quoted */
XString ds; /* destination string */
char *dp, *sp; /* dest., source */
int fdo, word; /* second pass flags; have word */
int doblank; /* field splitting of parameter/command subst */
Expand x = {
/* expansion variables */
NULL, { NULL }, NULL, 0
};
SubType st_head, *st;
int newlines = 0; /* For trailing newlines in COMSUB */
int saw_eq, tilde_ok;
int make_magic;
size_t len;
if (cp == NULL)
internal_errorf("expand(NULL)");
/* for alias, readonly, set, typeset commands */
if ((f & DOVACHECK) && is_wdvarassign(cp)) {
f &= ~(DOVACHECK|DOBLANK|DOGLOB|DOTILDE);
f |= DOASNTILDE;
}
if (Flag(FNOGLOB))
f &= ~DOGLOB;
if (Flag(FMARKDIRS))
f |= DOMARKDIRS;
if (Flag(FBRACEEXPAND) && (f & DOGLOB))
f |= DOBRACE_;
Xinit(ds, dp, 128, ATEMP); /* init dest. string */
type = XBASE;
sp = cp;
fdo = 0;
saw_eq = 0;
tilde_ok = (f & (DOTILDE|DOASNTILDE)) ? 1 : 0; /* must be 1/0 */
doblank = 0;
make_magic = 0;
word = (f&DOBLANK) ? IFS_WS : IFS_WORD;
memset(&st_head, 0, sizeof(st_head));
st = &st_head;
while (1) {
Xcheck(ds, dp);
switch (type) {
case XBASE: /* original prefixed string */
c = *sp++;
switch (c) {
case EOS:
c = 0;
break;
case CHAR:
c = *sp++;
break;
case QCHAR:
quote |= 2; /* temporary quote */
c = *sp++;
break;
case OQUOTE:
switch (word) {
case IFS_QUOTE:
/* """something */
word = IFS_WORD;
break;
case IFS_WORD:
break;
default:
word = IFS_QUOTE;
break;
}
tilde_ok = 0;
quote = 1;
continue;
case CQUOTE:
quote = 0;
continue;
case COMSUB:
tilde_ok = 0;
if (f & DONTRUNCOMMAND) {
word = IFS_WORD;
*dp++ = '$'; *dp++ = '(';
while (*sp != '\0') {
Xcheck(ds, dp);
*dp++ = *sp++;
}
*dp++ = ')';
} else {
type = comsub(&x, sp);
if (type == XCOM && (f&DOBLANK))
doblank++;
sp = strchr(sp, 0) + 1;
newlines = 0;
}
continue;
case EXPRSUB:
word = IFS_WORD;
tilde_ok = 0;
if (f & DONTRUNCOMMAND) {
*dp++ = '$'; *dp++ = '('; *dp++ = '(';
while (*sp != '\0') {
Xcheck(ds, dp);
*dp++ = *sp++;
}
*dp++ = ')'; *dp++ = ')';
} else {
struct tbl v;
char *p;
v.flag = DEFINED|ISSET|INTEGER;
v.type = 10; /* not default */
v.name[0] = '\0';
v_evaluate(&v, substitute(sp, 0),
KSH_UNWIND_ERROR, true);
sp = strchr(sp, 0) + 1;
for (p = str_val(&v); *p; ) {
Xcheck(ds, dp);
*dp++ = *p++;
}
}
continue;
case OSUBST: /* ${{#}var{:}[=+-?#%]word} */
/* format is:
* OSUBST [{x] plain-variable-part \0
* compiled-word-part CSUBST [}x]
* This is where all syntax checking gets done...
*/
{
char *varname = ++sp; /* skip the { or x (}) */
int stype;
int slen = 0;
sp = strchr(sp, '\0') + 1; /* skip variable */
type = varsub(&x, varname, sp, &stype, &slen);
if (type < 0) {
char endc;
char *str, *end;
sp = varname - 2; /* restore sp */
end = (char *) wdscan(sp, CSUBST);
/* ({) the } or x is already skipped */
endc = *end;
*end = EOS;
str = snptreef(NULL, 64, "%S", sp);
*end = endc;
errorf("%s: bad substitution", str);
}
if (f&DOBLANK)
doblank++;
tilde_ok = 0;
if (word == IFS_QUOTE && type != XNULLSUB)
word = IFS_WORD;
if (type == XBASE) { /* expand? */
if (!st->next) {
SubType *newst;
newst = alloc(
sizeof(SubType), ATEMP);
newst->next = NULL;
newst->prev = st;
st->next = newst;
}
st = st->next;
st->stype = stype;
st->base = Xsavepos(ds, dp);
st->f = f;
st->var = varcpy(x.var);
st->quote = quote;
/* skip qualifier(s) */
if (stype)
sp += slen;
switch (stype & 0x7f) {
case '#':
case '%':
/* ! DOBLANK,DOBRACE_,DOTILDE */
f = DOPAT | (f&DONTRUNCOMMAND) |
DOTEMP_;
quote = 0;
/* Prepend open pattern (so |
* in a trim will work as
* expected)
*/
*dp++ = MAGIC;
*dp++ = '@' + 0x80U;
break;
case '=':
/* Enabling tilde expansion
* after :'s here is
* non-standard ksh, but is
* consistent with rules for
* other assignments. Not
* sure what POSIX thinks of
* this.
* Not doing tilde expansion
* for integer variables is a
* non-POSIX thing - makes
* sense though, since ~ is
* a arithmetic operator.
*/
if (!(x.var->flag & INTEGER))
f |= DOASNTILDE|DOTILDE;
f |= DOTEMP_;
/* These will be done after the
* value has been assigned.
*/
f &= ~(DOBLANK|DOGLOB|DOBRACE_);
tilde_ok = 1;
break;
case '?':
f &= ~DOBLANK;
f |= DOTEMP_;
/* FALLTHROUGH */
default:
/* '-' '+' '?' */
if (quote)
word = IFS_WORD;
else if (dp == Xstring(ds, dp))
word = IFS_IWS;
/* Enable tilde expansion */
tilde_ok = 1;
f |= DOTILDE;
}
} else
/* skip word */
sp = (char *) wdscan(sp, CSUBST);
continue;
}
case CSUBST: /* only get here if expanding word */
sp++; /* ({) skip the } or x */
tilde_ok = 0; /* in case of ${unset:-} */
*dp = '\0';
quote = st->quote;
f = st->f;
if (f&DOBLANK)
doblank--;
switch (st->stype&0x7f) {
case '#':
case '%':
/* Append end-pattern */
*dp++ = MAGIC; *dp++ = ')'; *dp = '\0';
dp = Xrestpos(ds, dp, st->base);
/* Must use st->var since calling
* global would break things
* like x[i+=1].
*/
x.str = trimsub(str_val(st->var),
dp, st->stype);
if (x.str[0] != '\0') {
word = IFS_IWS;
type = XSUB;
} else if (quote) {
word = IFS_WORD;
type = XSUB;
} else {
if (dp == Xstring(ds, dp))
word = IFS_IWS;
type = XNULLSUB;
}
if (f&DOBLANK)
doblank++;
st = st->prev;
continue;
case '=':
/* Restore our position and substitute
* the value of st->var (may not be
* the assigned value in the presence
* of integer/right-adj/etc attributes).
*/
dp = Xrestpos(ds, dp, st->base);
/* Must use st->var since calling
* global would cause with things
* like x[i+=1] to be evaluated twice.
*/
/* Note: not exported by FEXPORT
* in at&t ksh.
*/
/* XXX POSIX says readonly is only
* fatal for special builtins (setstr
* does readonly check).
*/
len = strlen(dp) + 1;
setstr(st->var,
debunk(alloc(len, ATEMP),
dp, len), KSH_UNWIND_ERROR);
x.str = str_val(st->var);
type = XSUB;
if (f&DOBLANK)
doblank++;
st = st->prev;
if (quote || !*x.str)
word = IFS_WORD;
else
word = IFS_IWS;
continue;
case '?':
{
char *s = Xrestpos(ds, dp, st->base);
errorf("%s: %s", st->var->name,
dp == s ?
"parameter null or not set" :
(debunk(s, s, strlen(s) + 1), s));
}
}
st = st->prev;
type = XBASE;
continue;
case OPAT: /* open pattern: *(foo|bar) */
/* Next char is the type of pattern */
make_magic = 1;
c = *sp++ + 0x80;
break;
case SPAT: /* pattern separator (|) */
make_magic = 1;
c = '|';
break;
case CPAT: /* close pattern */
make_magic = 1;
c = /*(*/ ')';
break;
}
break;
case XNULLSUB:
/* Special case for "$@" (and "${foo[@]}") - no
* word is generated if $# is 0 (unless there is
* other stuff inside the quotes).
*/
type = XBASE;
if (f&DOBLANK) {
doblank--;
if (dp == Xstring(ds, dp) && word != IFS_WORD)
word = IFS_IWS;
}
continue;
case XSUB:
case XSUBMID:
if ((c = *x.str++) == 0) {
type = XBASE;
if (f&DOBLANK)
doblank--;
continue;
}
break;
case XARGSEP:
type = XARG;
quote = 1;
case XARG:
if ((c = *x.str++) == '\0') {
/* force null words to be created so
* set -- '' 2 ''; foo "$@" will do
* the right thing
*/
if (quote && x.split)
word = IFS_WORD;
if ((x.str = *x.u.strv++) == NULL) {
type = XBASE;
if (f&DOBLANK)
doblank--;
continue;
}
c = ifs0;
if (c == 0) {
if (quote && !x.split)
continue;
if (!quote && word == IFS_WS)
continue;
/* this is so we don't terminate */
c = ' ';
/* now force-emit a word */
goto emit_word;
}
if (quote && x.split) {
/* terminate word for "$@" */
type = XARGSEP;
quote = 0;
}
}
break;
case XCOM:
if (x.u.shf == NULL) /* $(< ...) failed, fake EOF */
c = EOF;
else if (newlines) { /* Spit out saved nl's */
c = '\n';
--newlines;
} else {
while ((c = shf_getc(x.u.shf)) == 0 || c == '\n')
if (c == '\n')
newlines++; /* Save newlines */
if (newlines && c != EOF) {
shf_ungetc(c, x.u.shf);
c = '\n';
--newlines;
}
}
if (c == EOF) {
newlines = 0;
if (x.u.shf != NULL)
shf_close(x.u.shf);
if (x.split)
subst_exstat = waitlast();
else
subst_exstat = (x.u.shf == NULL);
type = XBASE;
if (f&DOBLANK)
doblank--;
continue;
}
break;
}
/* check for end of word or IFS separation */
if (c == 0 || (!quote && (f & DOBLANK) && doblank &&
!make_magic && ctype(c, C_IFS))) {
/* How words are broken up:
* | value of c
* word | ws nws 0
* -----------------------------------
* IFS_WORD w/WS w/NWS w
* IFS_WS -/WS w/NWS -
* IFS_NWS -/NWS w/NWS -
* IFS_IWS -/WS w/NWS -
* (w means generate a word)
*/
if ((word == IFS_WORD) || (word == IFS_QUOTE) || (c &&
(word == IFS_IWS || word == IFS_NWS) &&
!ctype(c, C_IFSWS))) {
char *p;
emit_word:
*dp++ = '\0';
p = Xclose(ds, dp);
if (fdo & DOBRACE_)
/* also does globbing */
alt_expand(wp, p, p,
p + Xlength(ds, (dp - 1)),
fdo | (f & DOMARKDIRS));
else if (fdo & DOGLOB)
glob(p, wp, f & DOMARKDIRS);
else if ((f & DOPAT) || !(fdo & DOMAGIC_))
XPput(*wp, p);
else
XPput(*wp, debunk(p, p, strlen(p) + 1));
fdo = 0;
saw_eq = 0;
tilde_ok = (f & (DOTILDE|DOASNTILDE)) ? 1 : 0;
if (c != 0)
Xinit(ds, dp, 128, ATEMP);
}
if (c == 0)
goto done;
if (word != IFS_NWS)
word = ctype(c, C_IFSWS) ? IFS_WS : IFS_NWS;
} else {
if (type == XSUB) {
if (word == IFS_NWS &&
Xlength(ds, dp) == 0) {
char *p;
if ((p = strdup("")) == NULL)
internal_errorf("unable "
"to allocate memory");
XPput(*wp, p);
}
type = XSUBMID;
}
/* age tilde_ok info - ~ code tests second bit */
tilde_ok <<= 1;
/* mark any special second pass chars */
if (!quote)
switch (c) {
case '[':
case '!':
case '-':
case ']':
/* For character classes - doesn't hurt
* to have magic !,-,]'s outside of
* [...] expressions.
*/
if (f & (DOPAT | DOGLOB)) {
fdo |= DOMAGIC_;
if (c == '[')
fdo |= f & DOGLOB;
*dp++ = MAGIC;
}
break;
case '*':
case '?':
if (f & (DOPAT | DOGLOB)) {
fdo |= DOMAGIC_ | (f & DOGLOB);
*dp++ = MAGIC;
}
break;
case OBRACE:
case ',':
case CBRACE:
if ((f & DOBRACE_) && (c == OBRACE ||
(fdo & DOBRACE_))) {
fdo |= DOBRACE_|DOMAGIC_;
*dp++ = MAGIC;
}
break;
case '=':
/* Note first unquoted = for ~ */
if (!(f & DOTEMP_) && !saw_eq) {
saw_eq = 1;
tilde_ok = 1;
}
break;
case ':': /* : */
/* Note unquoted : for ~ */
if (!(f & DOTEMP_) && (f & DOASNTILDE))
tilde_ok = 1;
break;
case '~':
/* tilde_ok is reset whenever
* any of ' " $( $(( ${ } are seen.
* Note that tilde_ok must be preserved
* through the sequence ${A=a=}~
*/
if (type == XBASE &&
(f & (DOTILDE|DOASNTILDE)) &&
(tilde_ok & 2)) {
char *p, *dp_x;
dp_x = dp;
p = maybe_expand_tilde(sp,
&ds, &dp_x,
f & DOASNTILDE);
if (p) {
if (dp != dp_x)
word = IFS_WORD;
dp = dp_x;
sp = p;
continue;
}
}
break;
}
else
quote &= ~2; /* undo temporary */
if (make_magic) {
make_magic = 0;
fdo |= DOMAGIC_ | (f & DOGLOB);
*dp++ = MAGIC;
} else if (ISMAGIC(c)) {
fdo |= DOMAGIC_;
*dp++ = MAGIC;
}
*dp++ = c; /* save output char */
word = IFS_WORD;
}
}
done:
for (st = &st_head; st != NULL; st = st->next) {
if (st->var == NULL || (st->var->flag & RDONLY) == 0)
continue;
afree(st->var, ATEMP);
}
}
/*
* Prepare to generate the string returned by ${} substitution.
*/
static int
varsub(Expand *xp, char *sp, char *word,
int *stypep, /* becomes qualifier type */
int *slenp) /* " " len (=, :=, etc.) valid iff *stypep != 0 */
{
int c;
int state; /* next state: XBASE, XARG, XSUB, XNULLSUB */
int stype; /* substitution type */
int slen;
char *p;
struct tbl *vp;
int zero_ok = 0;
if (sp[0] == '\0') /* Bad variable name */
return -1;
xp->var = NULL;
/* ${#var}, string length or array size */
if (sp[0] == '#' && (c = sp[1]) != '\0') {
/* Can't have any modifiers for ${#...} */
if (*word != CSUBST)
return -1;
sp++;
/* Check for size of array */
if ((p=strchr(sp,'[')) && (p[1]=='*'||p[1]=='@') && p[2]==']') {
int n = 0;
vp = global(arrayname(sp));
if (vp->flag & (ISSET|ARRAY))
zero_ok = 1;
for (; vp; vp = vp->u.array)
if (vp->flag & ISSET)
n++;
c = n; /* ksh88/ksh93 go for number, not max index */
} else if (c == '*' || c == '@')
c = genv->loc->argc;
else {
p = str_val(global(sp));
zero_ok = p != null;
c = strlen(p);
}
if (Flag(FNOUNSET) && c == 0 && !zero_ok)
errorf("%s: parameter not set", sp);
*stypep = 0; /* unqualified variable/string substitution */
xp->str = str_save(u64ton((uint64_t)c, 10), ATEMP);
return XSUB;
}
/* Check for qualifiers in word part */
stype = 0;
c = word[slen = 0] == CHAR ? word[1] : 0;
if (c == ':') {
slen += 2;
stype = 0x80;
c = word[slen + 0] == CHAR ? word[slen + 1] : 0;
}
if (ctype(c, C_SUBOP1)) {
slen += 2;
stype |= c;
} else if (ctype(c, C_SUBOP2)) { /* Note: ksh88 allows :%, :%%, etc */
slen += 2;
stype = c;
if (word[slen + 0] == CHAR && c == word[slen + 1]) {
stype |= 0x80;
slen += 2;
}
} else if (stype) /* : is not ok */
return -1;
if (!stype && *word != CSUBST)
return -1;
*stypep = stype;
*slenp = slen;
c = sp[0];
if (c == '*' || c == '@') {
switch (stype & 0x7f) {
case '=': /* can't assign to a vector */
case '%': /* can't trim a vector (yet) */
case '#':
return -1;
}
if (genv->loc->argc == 0) {
xp->str = null;
xp->var = global(sp);
state = c == '@' ? XNULLSUB : XSUB;
} else {
xp->u.strv = (const char **) genv->loc->argv + 1;
xp->str = *xp->u.strv++;
xp->split = c == '@'; /* $@ */
state = XARG;
}
zero_ok = 1; /* exempt "$@" and "$*" from 'set -u' */
} else {
if ((p=strchr(sp,'[')) && (p[1]=='*'||p[1]=='@') && p[2]==']') {
XPtrV wv;
switch (stype & 0x7f) {
case '=': /* can't assign to a vector */
case '%': /* can't trim a vector (yet) */
case '#':
case '?':
return -1;
}
XPinit(wv, 32);
vp = global(arrayname(sp));
for (; vp; vp = vp->u.array) {
if (!(vp->flag&ISSET))
continue;
XPput(wv, str_val(vp));
}
if (XPsize(wv) == 0) {
xp->str = null;
state = p[1] == '@' ? XNULLSUB : XSUB;
XPfree(wv);
} else {
XPput(wv, 0);
xp->u.strv = (const char **) XPptrv(wv);
xp->str = *xp->u.strv++;
xp->split = p[1] == '@'; /* ${foo[@]} */
state = XARG;
}
} else {
/* Can't assign things like $! or $1 */
if ((stype & 0x7f) == '=' &&
(ctype(*sp, C_VAR1) || digit(*sp)))
return -1;
xp->var = global(sp);
xp->str = str_val(xp->var);
state = XSUB;
}
}
c = stype&0x7f;
/* test the compiler's code generator */
if (ctype(c, C_SUBOP2) ||
(((stype&0x80) ? *xp->str=='\0' : xp->str==null) ? /* undef? */
c == '=' || c == '-' || c == '?' : c == '+'))
state = XBASE; /* expand word instead of variable value */
if (Flag(FNOUNSET) && xp->str == null && !zero_ok &&
(ctype(c, C_SUBOP2) || (state != XBASE && c != '+')))
errorf("%s: parameter not set", sp);
return state;
}
/*
* Run the command in $(...) and read its output.
*/
static int
comsub(Expand *xp, char *cp)
{
Source *s, *sold;
struct op *t;
struct shf *shf;
s = pushs(SSTRING, ATEMP);
s->start = s->str = cp;
sold = source;
t = compile(s);
afree(s, ATEMP);
source = sold;
if (t == NULL)
return XBASE;
if (t != NULL && t->type == TCOM && /* $(<file) */
*t->args == NULL && *t->vars == NULL && t->ioact != NULL) {
struct ioword *io = *t->ioact;
char *name;
if ((io->flag&IOTYPE) != IOREAD)
errorf("funny $() command: %s",
snptreef(NULL, 32, "%R", io));
shf = shf_open(name = evalstr(io->name, DOTILDE), O_RDONLY, 0,
SHF_MAPHI|SHF_CLEXEC);
if (shf == NULL)
warningf(!Flag(FTALKING),
"%s: %s", name, strerror(errno));
xp->split = 0; /* no waitlast() */
} else {
int ofd1, pv[2];
openpipe(pv);
shf = shf_fdopen(pv[0], SHF_RD, NULL);
ofd1 = savefd(1);
if (pv[1] != 1) {
ksh_dup2(pv[1], 1, false);
close(pv[1]);
}
execute(t, XFORK|XXCOM|XPIPEO, NULL);
restfd(1, ofd1);
startlast();
xp->split = 1; /* waitlast() */
}
xp->u.shf = shf;
return XCOM;
}
/*
* perform #pattern and %pattern substitution in ${}
*/
static char *
trimsub(char *str, char *pat, int how)
{
char *end = strchr(str, 0);
char *p, c;
switch (how&0xff) { /* UCHAR_MAX maybe? */
case '#': /* shortest at beginning */
for (p = str; p <= end; p++) {
c = *p; *p = '\0';
if (gmatch(str, pat, false)) {
*p = c;
return p;
}
*p = c;
}
break;
case '#'|0x80: /* longest match at beginning */
for (p = end; p >= str; p--) {
c = *p; *p = '\0';
if (gmatch(str, pat, false)) {
*p = c;
return p;
}
*p = c;
}
break;
case '%': /* shortest match at end */
for (p = end; p >= str; p--) {
if (gmatch(p, pat, false))
return str_nsave(str, p - str, ATEMP);
}
break;
case '%'|0x80: /* longest match at end */
for (p = str; p <= end; p++) {
if (gmatch(p, pat, false))
return str_nsave(str, p - str, ATEMP);
}
break;
}
return str; /* no match, return string */
}
/*
* glob
* Name derived from V6's /etc/glob, the program that expanded filenames.
*/
/* XXX cp not const 'cause slashes are temporarily replaced with nulls... */
static void
glob(char *cp, XPtrV *wp, int markdirs)
{
int oldsize = XPsize(*wp);
if (glob_str(cp, wp, markdirs) == 0)
XPput(*wp, debunk(cp, cp, strlen(cp) + 1));
else
qsortp(XPptrv(*wp) + oldsize, (size_t)(XPsize(*wp) - oldsize),
xstrcmp);
}
#define GF_NONE 0
#define GF_EXCHECK BIT(0) /* do existence check on file */
#define GF_GLOBBED BIT(1) /* some globbing has been done */
#define GF_MARKDIR BIT(2) /* add trailing / to directories */
/* Apply file globbing to cp and store the matching files in wp. Returns
* the number of matches found.
*/
int
glob_str(char *cp, XPtrV *wp, int markdirs)
{
int oldsize = XPsize(*wp);
XString xs;
char *xp;
Xinit(xs, xp, 256, ATEMP);
globit(&xs, &xp, cp, wp, markdirs ? GF_MARKDIR : GF_NONE);
Xfree(xs, xp);
return XPsize(*wp) - oldsize;
}
static void
globit(XString *xs, /* dest string */
char **xpp, /* ptr to dest end */
char *sp, /* source path */
XPtrV *wp, /* output list */
int check) /* GF_* flags */
{
char *np; /* next source component */
char *xp = *xpp;
char *se;
char odirsep;
/* This to allow long expansions to be interrupted */
intrcheck();
if (sp == NULL) { /* end of source path */
/* We only need to check if the file exists if a pattern
* is followed by a non-pattern (eg, foo*x/bar; no check
* is needed for foo* since the match must exist) or if
* any patterns were expanded and the markdirs option is set.
* Symlinks make things a bit tricky...
*/
if ((check & GF_EXCHECK) ||
((check & GF_MARKDIR) && (check & GF_GLOBBED))) {
#define stat_check() (stat_done ? stat_done : \
(stat_done = stat(Xstring(*xs, xp), &statb) == -1 \
? -1 : 1))
struct stat lstatb, statb;
int stat_done = 0; /* -1: failed, 1 ok */
if (lstat(Xstring(*xs, xp), &lstatb) == -1)
return;
/* special case for systems which strip trailing
* slashes from regular files (eg, /etc/passwd/).
* SunOS 4.1.3 does this...
*/
if ((check & GF_EXCHECK) && xp > Xstring(*xs, xp) &&
xp[-1] == '/' && !S_ISDIR(lstatb.st_mode) &&
(!S_ISLNK(lstatb.st_mode) ||
stat_check() < 0 || !S_ISDIR(statb.st_mode)))
return;
/* Possibly tack on a trailing / if there isn't already
* one and if the file is a directory or a symlink to a
* directory
*/
if (((check & GF_MARKDIR) && (check & GF_GLOBBED)) &&
xp > Xstring(*xs, xp) && xp[-1] != '/' &&
(S_ISDIR(lstatb.st_mode) ||
(S_ISLNK(lstatb.st_mode) && stat_check() > 0 &&
S_ISDIR(statb.st_mode)))) {
*xp++ = '/';
*xp = '\0';
}
}
XPput(*wp, str_nsave(Xstring(*xs, xp), Xlength(*xs, xp), ATEMP));
return;
}
if (xp > Xstring(*xs, xp))
*xp++ = '/';
while (*sp == '/') {
Xcheck(*xs, xp);
*xp++ = *sp++;
}
np = strchr(sp, '/');
if (np != NULL) {
se = np;
odirsep = *np; /* don't assume '/', can be multiple kinds */
*np++ = '\0';
} else {
odirsep = '\0'; /* keep gcc quiet */
se = sp + strlen(sp);
}
/* Check if sp needs globbing - done to avoid pattern checks for strings
* containing MAGIC characters, open ['s without the matching close ],
* etc. (otherwise opendir() will be called which may fail because the
* directory isn't readable - if no globbing is needed, only execute
* permission should be required (as per POSIX)).
*/
if (!has_globbing(sp, se)) {
XcheckN(*xs, xp, se - sp + 1);
debunk(xp, sp, Xnleft(*xs, xp));
xp += strlen(xp);
*xpp = xp;
globit(xs, xpp, np, wp, check);
} else {
DIR *dirp;
struct dirent *d;
char *name;
int len;
int prefix_len;
*xp = '\0';
prefix_len = Xlength(*xs, xp);
dirp = opendir(prefix_len ? Xstring(*xs, xp) : ".");
if (dirp == NULL)
goto Nodir;
while ((d = readdir(dirp)) != NULL) {
name = d->d_name;
if (name[0] == '.' &&
(name[1] == 0 || (name[1] == '.' && name[2] == 0)))
continue; /* always ignore . and .. */
if ((*name == '.' && *sp != '.') ||
!gmatch(name, sp, true))
continue;
len = strlen(d->d_name) + 1;
XcheckN(*xs, xp, len);
memcpy(xp, name, len);
*xpp = xp + len - 1;
globit(xs, xpp, np, wp,
(check & GF_MARKDIR) | GF_GLOBBED
| (np ? GF_EXCHECK : GF_NONE));
xp = Xstring(*xs, xp) + prefix_len;
}
closedir(dirp);
Nodir:;
}
if (np != NULL)
*--np = odirsep;
}
/* remove MAGIC from string */
char *
debunk(char *dp, const char *sp, size_t dlen)
{
char *d, *s;
if ((s = strchr(sp, MAGIC))) {
size_t slen = s - sp;
if (slen >= dlen)
return dp;
memcpy(dp, sp, slen);
for (d = dp + slen; *s && (d < dp + dlen); s++)
if (!ISMAGIC(*s) || !(*++s & 0x80) ||
!strchr("*+?@! ", *s & 0x7f))
*d++ = *s;
else {
/* extended pattern operators: *+?@! */
if ((*s & 0x7f) != ' ')
*d++ = *s & 0x7f;
if (d < dp + dlen)
*d++ = '(';
}
*d = '\0';
} else if (dp != sp)
strlcpy(dp, sp, dlen);
return dp;
}
/* Check if p is an unquoted name, possibly followed by a / or :. If so
* puts the expanded version in *dcp,dp and returns a pointer in p just
* past the name, otherwise returns 0.
*/
static char *
maybe_expand_tilde(char *p, XString *dsp, char **dpp, int isassign)
{
XString ts;
char *dp = *dpp;
char *tp, *r;
Xinit(ts, tp, 16, ATEMP);
/* : only for DOASNTILDE form */
while (p[0] == CHAR && p[1] != '/' && (!isassign || p[1] != ':'))
{
Xcheck(ts, tp);
*tp++ = p[1];
p += 2;
}
*tp = '\0';
r = (p[0] == EOS || p[0] == CHAR || p[0] == CSUBST) ?
tilde(Xstring(ts, tp)) : NULL;
Xfree(ts, tp);
if (r) {
while (*r) {
Xcheck(*dsp, dp);
if (ISMAGIC(*r))
*dp++ = MAGIC;
*dp++ = *r++;
}
*dpp = dp;
r = p;
}
return r;
}
/*
* tilde expansion
*
* based on a version by Arnold Robbins
*/
static char *
tilde(char *cp)
{
char *dp;
if (cp[0] == '\0')
dp = str_val(global("HOME"));
else if (cp[0] == '+' && cp[1] == '\0')
dp = str_val(global("PWD"));
else if (cp[0] == '-' && cp[1] == '\0')
dp = str_val(global("OLDPWD"));
else
dp = homedir(cp);
/* If HOME, PWD or OLDPWD are not set, don't expand ~ */
if (dp == null)
dp = NULL;
return dp;
}
/*
* map userid to user's home directory.
* note that 4.3's getpw adds more than 6K to the shell,
* and the YP version probably adds much more.
* we might consider our own version of getpwnam() to keep the size down.
*/
static char *
homedir(char *name)
{
struct tbl *ap;
ap = ktenter(&homedirs, name, hash(name));
if (!(ap->flag & ISSET)) {
struct passwd *pw;
pw = getpwnam(name);
if (pw == NULL)
return NULL;
ap->val.s = str_save(pw->pw_dir, APERM);
ap->flag |= DEFINED|ISSET|ALLOC;
}
return ap->val.s;
}
static void
alt_expand(XPtrV *wp, char *start, char *exp_start, char *end, int fdo)
{
int count = 0;
char *brace_start, *brace_end, *comma = NULL;
char *field_start;
char *p;
/* search for open brace */
for (p = exp_start; (p = strchr(p, MAGIC)) && p[1] != OBRACE; p += 2)
;
brace_start = p;
/* find matching close brace, if any */
if (p) {
comma = NULL;
count = 1;
for (p += 2; *p && count; p++) {
if (ISMAGIC(*p)) {
if (*++p == OBRACE)
count++;
else if (*p == CBRACE)
--count;
else if (*p == ',' && count == 1)
comma = p;
}
}
}
/* no valid expansions... */
if (!p || count != 0) {
/* Note that given a{{b,c} we do not expand anything (this is
* what at&t ksh does. This may be changed to do the {b,c}
* expansion. }
*/
if (fdo & DOGLOB)
glob(start, wp, fdo & DOMARKDIRS);
else
XPput(*wp, debunk(start, start, end - start));
return;
}
brace_end = p;
if (!comma) {
alt_expand(wp, start, brace_end, end, fdo);
return;
}
/* expand expression */
field_start = brace_start + 2;
count = 1;
for (p = brace_start + 2; p != brace_end; p++) {
if (ISMAGIC(*p)) {
if (*++p == OBRACE)
count++;
else if ((*p == CBRACE && --count == 0) ||
(*p == ',' && count == 1)) {
char *new;
int l1, l2, l3;
l1 = brace_start - start;
l2 = (p - 1) - field_start;
l3 = end - brace_end;
new = alloc(l1 + l2 + l3 + 1, ATEMP);
memcpy(new, start, l1);
memcpy(new + l1, field_start, l2);
memcpy(new + l1 + l2, brace_end, l3);
new[l1 + l2 + l3] = '\0';
alt_expand(wp, new, new + l1,
new + l1 + l2 + l3, fdo);
field_start = p + 1;
}
}
}
return;
}
/*
* Copy the given variable if it's flagged as read-only.
* Such variables have static storage and only one can therefore be referenced
* at a time.
* This is necessary in order to allow variable expansion expressions to refer
* to multiple read-only variables.
*/
static struct tbl *
varcpy(struct tbl *vp)
{
struct tbl *cpy;
if (vp == NULL || (vp->flag & RDONLY) == 0)
return vp;
cpy = alloc(sizeof(struct tbl), ATEMP);
memcpy(cpy, vp, sizeof(struct tbl));
return cpy;
}
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