/*
* Perform expansions on an argument, placing the resulting list of arguments
* in arglist. Parameter expansion, command substitution and arithmetic
* expansion are always performed; additional expansions can be requested
* via flag (EXP_*).
* The result is left in the stack string.
* When arglist is NULL, perform here document expansion.
*
* When doing something that may cause this to be re-entered, make sure
* the stack string is empty via grabstackstr() and do not assume expdest
* remains valid.
*/
void
expandarg(union node *arg, struct arglist *arglist, int flag)
{
struct worddest exparg;
struct nodelist *argbackq;
if (fflag)
flag &= ~EXP_GLOB;
argbackq = arg->narg.backquote;
exparg.list = arglist;
exparg.state = WORD_IDLE;
STARTSTACKSTR(expdest);
argstr(arg->narg.text, &argbackq, flag, &exparg);
if (arglist == NULL) {
STACKSTRNUL(expdest);
return; /* here document expanded */
}
if ((flag & EXP_SPLIT) == 0 || expdest != stackblock() ||
exparg.state == WORD_QUOTEMARK) {
STPUTC('\0', expdest);
if (flag & EXP_SPLIT) {
if (flag & EXP_GLOB)
expandmeta(grabstackstr(expdest), exparg.list);
else
appendarglist(exparg.list, grabstackstr(expdest));
}
}
if ((flag & EXP_SPLIT) == 0)
appendarglist(arglist, grabstackstr(expdest));
}
/*
* Perform pathname generation and remove control characters.
* At this point, the only control characters should be CTLESC.
* The results are stored in the list dstlist.
*/
static void
expandmeta(char *pattern, struct arglist *dstlist)
{
char *p;
int firstmatch;
char c;
firstmatch = dstlist->count;
p = pattern;
for (; (c = *p) != '\0'; p++) {
/* fast check for meta chars */
if (c == '*' || c == '?' || c == '[') {
INTOFF;
expmeta(expdir, pattern, dstlist);
INTON;
break;
}
}
if (dstlist->count == firstmatch) {
/*
* no matches
*/
rmescapes(pattern);
appendarglist(dstlist, pattern);
} else {
qsort(&dstlist->args[firstmatch],
dstlist->count - firstmatch,
sizeof(dstlist->args[0]), expsortcmp);
}
}
static char *
nextword(char c, int flag, char *p, struct worddest *dst)
{
int is_ws;
is_ws = c == '\t' || c == '\n' || c == ' ';
if (p != stackblock() || (is_ws ? dst->state == WORD_QUOTEMARK :
dst->state != WORD_WS_DELIMITED) || c == '\0') {
STPUTC('\0', p);
if (flag & EXP_GLOB)
expandmeta(grabstackstr(p), dst->list);
else
appendarglist(dst->list, grabstackstr(p));
dst->state = is_ws ? WORD_WS_DELIMITED : WORD_IDLE;
} else if (!is_ws && dst->state == WORD_WS_DELIMITED)
dst->state = WORD_IDLE;
/* Reserve space while the stack string is empty. */
appendarglist(dst->list, NULL);
dst->list->count--;
STARTSTACKSTR(p);
return p;
}
static void
evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
{
union node *argp;
struct arglist arglist;
struct arglist varlist;
char **argv;
int argc;
char **envp;
int varflag;
int mode;
int pip[2];
struct cmdentry cmdentry;
struct job *jp;
struct jmploc jmploc;
struct jmploc *savehandler;
char *savecmdname;
struct shparam saveparam;
struct localvar *savelocalvars;
struct parsefile *savetopfile;
volatile int e;
char *lastarg;
int realstatus;
int do_clearcmdentry;
const char *path = pathval();
int i;
/* First expand the arguments. */
TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
emptyarglist(&arglist);
emptyarglist(&varlist);
varflag = 1;
jp = NULL;
do_clearcmdentry = 0;
oexitstatus = exitstatus;
exitstatus = 0;
/* Add one slot at the beginning for tryexec(). */
appendarglist(&arglist, nullstr);
for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
if (varflag && isassignment(argp->narg.text)) {
expandarg(argp, varflag == 1 ? &varlist : &arglist,
EXP_VARTILDE);
continue;
} else if (varflag == 1)
varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
}
appendarglist(&arglist, nullstr);
expredir(cmd->ncmd.redirect);
argc = arglist.count - 2;
argv = &arglist.args[1];
argv[argc] = NULL;
lastarg = NULL;
if (iflag && funcnest == 0 && argc > 0)
lastarg = argv[argc - 1];
/* Print the command if xflag is set. */
if (xflag)
xtracecommand(&varlist, argc, argv);
/* Now locate the command. */
if (argc == 0) {
/* Variable assignment(s) without command */
cmdentry.cmdtype = CMDBUILTIN;
cmdentry.u.index = BLTINCMD;
cmdentry.special = 0;
} else {
static const char PATH[] = "PATH=";
int cmd_flags = 0, bltinonly = 0;
/*
* Modify the command lookup path, if a PATH= assignment
* is present
*/
for (i = 0; i < varlist.count; i++)
if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) {
path = varlist.args[i] + sizeof(PATH) - 1;
/*
* On `PATH=... command`, we need to make
* sure that the command isn't using the
* non-updated hash table of the outer PATH
* setting and we need to make sure that
* the hash table isn't filled with items
* from the temporary setting.
*
* It would be better to forbit using and
* updating the table while this command
* runs, by the command finding mechanism
* is heavily integrated with hash handling,
* so we just delete the hash before and after
* the command runs. Partly deleting like
* changepatch() does doesn't seem worth the
* bookinging effort, since most such runs add
* directories in front of the new PATH.
*/
clearcmdentry();
do_clearcmdentry = 1;
}
for (;;) {
if (bltinonly) {
cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
if (cmdentry.u.index < 0) {
cmdentry.u.index = BLTINCMD;
argv--;
argc++;
break;
}
} else
find_command(argv[0], &cmdentry, cmd_flags, path);
/* implement the bltin and command builtins here */
if (cmdentry.cmdtype != CMDBUILTIN)
break;
if (cmdentry.u.index == BLTINCMD) {
if (argc == 1)
break;
argv++;
argc--;
bltinonly = 1;
} else if (cmdentry.u.index == COMMANDCMD) {
if (argc == 1)
break;
if (!strcmp(argv[1], "-p")) {
if (argc == 2)
break;
if (argv[2][0] == '-') {
if (strcmp(argv[2], "--"))
break;
if (argc == 3)
break;
argv += 3;
argc -= 3;
} else {
argv += 2;
argc -= 2;
}
path = _PATH_STDPATH;
clearcmdentry();
do_clearcmdentry = 1;
} else if (!strcmp(argv[1], "--")) {
if (argc == 2)
break;
argv += 2;
argc -= 2;
} else if (argv[1][0] == '-')
break;
else {
argv++;
argc--;
}
cmd_flags |= DO_NOFUNC;
bltinonly = 0;
} else
break;
}
/*
* Special builtins lose their special properties when
* called via 'command'.
*/
if (cmd_flags & DO_NOFUNC)
cmdentry.special = 0;
}
/* Fork off a child process if necessary. */
if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
&& ((flags & EV_EXIT) == 0 || have_traps()))
|| ((flags & EV_BACKCMD) != 0
&& (cmdentry.cmdtype != CMDBUILTIN ||
!safe_builtin(cmdentry.u.index, argc, argv)))) {
jp = makejob(cmd, 1);
mode = FORK_FG;
if (flags & EV_BACKCMD) {
mode = FORK_NOJOB;
if (pipe(pip) < 0)
error("Pipe call failed: %s", strerror(errno));
}
if (cmdentry.cmdtype == CMDNORMAL &&
cmd->ncmd.redirect == NULL &&
varlist.count == 0 &&
(mode == FORK_FG || mode == FORK_NOJOB) &&
!disvforkset() && !iflag && !mflag) {
vforkexecshell(jp, argv, environment(), path,
cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
goto parent;
}
if (forkshell(jp, cmd, mode) != 0)
goto parent; /* at end of routine */
if (flags & EV_BACKCMD) {
FORCEINTON;
close(pip[0]);
if (pip[1] != 1) {
dup2(pip[1], 1);
close(pip[1]);
}
flags &= ~EV_BACKCMD;
}
flags |= EV_EXIT;
}
/* This is the child process if a fork occurred. */
/* Execute the command. */
if (cmdentry.cmdtype == CMDFUNCTION) {
#ifdef DEBUG
trputs("Shell function: "); trargs(argv);
#endif
saveparam = shellparam;
shellparam.malloc = 0;
shellparam.reset = 1;
shellparam.nparam = argc - 1;
shellparam.p = argv + 1;
shellparam.optp = NULL;
shellparam.optnext = NULL;
INTOFF;
savelocalvars = localvars;
localvars = NULL;
reffunc(cmdentry.u.func);
savehandler = handler;
if (setjmp(jmploc.loc)) {
freeparam(&shellparam);
shellparam = saveparam;
popredir();
unreffunc(cmdentry.u.func);
poplocalvars();
localvars = savelocalvars;
funcnest--;
handler = savehandler;
longjmp(handler->loc, 1);
}
handler = &jmploc;
funcnest++;
redirect(cmd->ncmd.redirect, REDIR_PUSH);
INTON;
for (i = 0; i < varlist.count; i++)
mklocal(varlist.args[i]);
exitstatus = oexitstatus;
evaltree(getfuncnode(cmdentry.u.func),
flags & (EV_TESTED | EV_EXIT));
INTOFF;
unreffunc(cmdentry.u.func);
poplocalvars();
localvars = savelocalvars;
freeparam(&shellparam);
shellparam = saveparam;
handler = savehandler;
funcnest--;
popredir();
INTON;
if (evalskip == SKIPRETURN) {
evalskip = 0;
skipcount = 0;
}
if (jp)
exitshell(exitstatus);
} else if (cmdentry.cmdtype == CMDBUILTIN) {
#ifdef DEBUG
trputs("builtin command: "); trargs(argv);
#endif
mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
if (flags == EV_BACKCMD) {
memout.nleft = 0;
memout.nextc = memout.buf;
memout.bufsize = 64;
mode |= REDIR_BACKQ;
}
savecmdname = commandname;
savetopfile = getcurrentfile();
cmdenviron = &varlist;
e = -1;
savehandler = handler;
if (setjmp(jmploc.loc)) {
e = exception;
if (e == EXINT)
exitstatus = SIGINT+128;
else if (e != EXEXIT)
exitstatus = 2;
goto cmddone;
}
handler = &jmploc;
redirect(cmd->ncmd.redirect, mode);
outclearerror(out1);
/*
* If there is no command word, redirection errors should
* not be fatal but assignment errors should.
*/
if (argc == 0)
cmdentry.special = 1;
listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
if (argc > 0)
bltinsetlocale();
commandname = argv[0];
argptr = argv + 1;
nextopt_optptr = NULL; /* initialize nextopt */
builtin_flags = flags;
exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
flushall();
if (outiserror(out1)) {
warning("write error on stdout");
if (exitstatus == 0 || exitstatus == 1)
exitstatus = 2;
}
cmddone:
if (argc > 0)
bltinunsetlocale();
cmdenviron = NULL;
out1 = &output;
out2 = &errout;
freestdout();
handler = savehandler;
commandname = savecmdname;
if (jp)
exitshell(exitstatus);
if (flags == EV_BACKCMD) {
backcmd->buf = memout.buf;
backcmd->nleft = memout.nextc - memout.buf;
memout.buf = NULL;
}
if (cmdentry.u.index != EXECCMD)
popredir();
if (e != -1) {
if ((e != EXERROR && e != EXEXEC)
|| cmdentry.special)
exraise(e);
popfilesupto(savetopfile);
if (flags != EV_BACKCMD)
FORCEINTON;
}
} else {
#ifdef DEBUG
trputs("normal command: "); trargs(argv);
#endif
redirect(cmd->ncmd.redirect, 0);
for (i = 0; i < varlist.count; i++)
setvareq(varlist.args[i], VEXPORT|VSTACK);
envp = environment();
shellexec(argv, envp, path, cmdentry.u.index);
/*NOTREACHED*/
}
goto out;
parent: /* parent process gets here (if we forked) */
if (mode == FORK_FG) { /* argument to fork */
INTOFF;
exitstatus = waitforjob(jp, &realstatus);
INTON;
if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
evalskip = SKIPBREAK;
skipcount = loopnest;
}
} else if (mode == FORK_NOJOB) {
backcmd->fd = pip[0];
close(pip[1]);
backcmd->jp = jp;
}
out:
if (lastarg)
setvar("_", lastarg, 0);
if (do_clearcmdentry)
clearcmdentry();
}
static void
expmeta(char *enddir, char *name, struct arglist *arglist)
{
const char *p;
const char *q;
const char *start;
char *endname;
int metaflag;
struct stat statb;
DIR *dirp;
struct dirent *dp;
int atend;
int matchdot;
int esc;
int namlen;
metaflag = 0;
start = name;
for (p = name; esc = 0, *p; p += esc + 1) {
if (*p == '*' || *p == '?')
metaflag = 1;
else if (*p == '[') {
q = p + 1;
if (*q == '!' || *q == '^')
q++;
for (;;) {
if (*q == CTLESC)
q++;
if (*q == '/' || *q == '\0')
break;
if (*++q == ']') {
metaflag = 1;
break;
}
}
} else if (*p == '\0')
break;
else {
if (*p == CTLESC)
esc++;
if (p[esc] == '/') {
if (metaflag)
break;
start = p + esc + 1;
}
}
}
if (metaflag == 0) { /* we've reached the end of the file name */
if (enddir != expdir)
metaflag++;
for (p = name ; ; p++) {
if (*p == CTLESC)
p++;
*enddir++ = *p;
if (*p == '\0')
break;
if (enddir == expdir_end)
return;
}
if (metaflag == 0 || lstat(expdir, &statb) >= 0)
appendarglist(arglist, stsavestr(expdir));
return;
}
endname = name + (p - name);
if (start != name) {
p = name;
while (p < start) {
if (*p == CTLESC)
p++;
*enddir++ = *p++;
if (enddir == expdir_end)
return;
}
}
if (enddir == expdir) {
p = ".";
} else if (enddir == expdir + 1 && *expdir == '/') {
p = "/";
} else {
p = expdir;
enddir[-1] = '\0';
}
if ((dirp = opendir(p)) == NULL)
return;
if (enddir != expdir)
enddir[-1] = '/';
if (*endname == 0) {
atend = 1;
} else {
atend = 0;
*endname = '\0';
endname += esc + 1;
}
matchdot = 0;
p = start;
if (*p == CTLESC)
p++;
if (*p == '.')
matchdot++;
while (! int_pending() && (dp = readdir(dirp)) != NULL) {
if (dp->d_name[0] == '.' && ! matchdot)
continue;
if (patmatch(start, dp->d_name)) {
namlen = dp->d_namlen;
if (enddir + namlen + 1 > expdir_end)
continue;
memcpy(enddir, dp->d_name, namlen + 1);
if (atend)
appendarglist(arglist, stsavestr(expdir));
else {
if (dp->d_type != DT_UNKNOWN &&
dp->d_type != DT_DIR &&
dp->d_type != DT_LNK)
continue;
if (enddir + namlen + 2 > expdir_end)
continue;
enddir[namlen] = '/';
enddir[namlen + 1] = '\0';
expmeta(enddir + namlen + 1, endname, arglist);
}
}
}
closedir(dirp);
if (! atend)
endname[-esc - 1] = esc ? CTLESC : '/';
}
