usr/dash/var.c

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * 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 <unistd.h>
#include <stdlib.h>
#include <paths.h>

/*
 * Shell variables.
 */

#include "shell.h"
#include "output.h"
#include "expand.h"
#include "nodes.h"	/* for other headers */
#include "eval.h"	/* defines cmdenviron */
#include "exec.h"
#include "syntax.h"
#include "options.h"
#include "mail.h"
#include "var.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "parser.h"
#include "show.h"
#ifndef SMALL
#include "myhistedit.h"
#endif
#include "system.h"


#define VTABSIZE 39


struct localvar *localvars;

const char defpathvar[] =
	"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
#ifdef IFS_BROKEN
const char defifsvar[] = "IFS= \t\n";
#else
const char defifs[] = " \t\n";
#endif

struct var varinit[] = {
#if ATTY
	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY\0",	0 },
#endif
#ifdef IFS_BROKEN
	{ 0,	VSTRFIXED|VTEXTFIXED,		defifsvar,	0 },
#else
	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"IFS\0",	0 },
#endif
	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL\0",	changemail },
	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH\0",	changemail },
	{ 0,	VSTRFIXED|VTEXTFIXED,		defpathvar,	changepath },
	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS1=$ ",	0 },
	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",	0 },
	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS4=+ ",	0 },
	{ 0,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",	getoptsreset },
	{ 0,	VSTRFIXED|VTEXTFIXED,		"LINENO=1",	0 },
#ifndef SMALL
	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM\0",	0 },
	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE\0",	sethistsize },
#endif
};

STATIC struct var *vartab[VTABSIZE];

STATIC void mklocal(char *);
STATIC struct var **hashvar(const char *);
STATIC int vpcmp(const void *, const void *);
STATIC struct var **findvar(struct var **, const char *);

/*
 * Initialize the varable symbol tables and import the environment
 */

#ifdef mkinit
INCLUDE <unistd.h>
INCLUDE <sys/types.h>
INCLUDE <sys/stat.h>
INCLUDE "cd.h"
INCLUDE "output.h"
INCLUDE "var.h"
MKINIT char **environ;
INIT {
	char **envp;
	static char ppid[32] = "PPID=";
	const char *p;
	struct stat st1, st2;

	initvar();
	for (envp = environ ; *envp ; envp++) {
		if (strchr(*envp, '=')) {
			setvareq(*envp, VEXPORT|VTEXTFIXED);
		}
	}

	fmtstr(ppid + 5, sizeof(ppid) - 5, "%ld", (long) getppid());
	setvareq(ppid, VTEXTFIXED);

	p = lookupvar("PWD");
	if (p)
		if (*p != '/' || stat(p, &st1) || stat(".", &st2) ||
		    st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
			p = 0;
	setpwd(p, 0);
}
#endif


/*
 * This routine initializes the builtin variables.  It is called when the
 * shell is initialized.
 */

void
initvar(void)
{
	struct var *vp;
	struct var *end;
	struct var **vpp;

	vp = varinit;
	end = vp + sizeof(varinit) / sizeof(varinit[0]);
	do {
		vpp = hashvar(vp->text);
		vp->next = *vpp;
		*vpp = vp;
	} while (++vp < end);
	/*
	 * PS1 depends on uid
	 */
	if (!geteuid())
		vps1.text = "PS1=# ";
}

/*
 * Set the value of a variable.  The flags argument is ored with the
 * flags of the variable.  If val is NULL, the variable is unset.
 */

void
setvar(const char *name, const char *val, int flags)
{
	char *p, *q;
	size_t namelen;
	char *nameeq;
	size_t vallen;

	q = endofname(name);
	p = strchrnul(q, '=');
	namelen = p - name;
	if (!namelen || p != q)
		sh_error("%.*s: bad variable name", namelen, name);
	vallen = 0;
	if (val == NULL) {
		flags |= VUNSET;
	} else {
		vallen = strlen(val);
	}
	INTOFF;
	p = mempcpy(nameeq = ckmalloc(namelen + vallen + 2), name, namelen);
	if (val) {
		*p++ = '=';
		p = mempcpy(p, val, vallen);
	}
	*p = '\0';
	setvareq(nameeq, flags | VNOSAVE);
	INTON;
}

/*
 * Set the given integer as the value of a variable.  The flags argument is
 * ored with the flags of the variable.
 */

intmax_t setvarint(const char *name, intmax_t val, int flags)
{
	int len = max_int_length(sizeof(val));
	char buf[len];

	fmtstr(buf, len, "%jd", val);
	setvar(name, buf, flags);
	return val;
}


/*
 * Same as setvar except that the variable and value are passed in
 * the first argument as name=value.  Since the first argument will
 * be actually stored in the table, it should not be a string that
 * will go away.
 * Called with interrupts off.
 */

void
setvareq(char *s, int flags)
{
	struct var *vp, **vpp;

	vpp = hashvar(s);
	flags |= (VEXPORT & (((unsigned) (1 - aflag)) - 1));
	vp = *findvar(vpp, s);
	if (vp) {
		if (vp->flags & VREADONLY) {
			const char *n;

			if (flags & VNOSAVE)
				free(s);
			n = vp->text;
			sh_error("%.*s: is read only", strchrnul(n, '=') - n,
				 n);
		}

		if (flags & VNOSET)
			return;

		if (vp->func && (flags & VNOFUNC) == 0)
			(*vp->func)(strchrnul(s, '=') + 1);

		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
			ckfree(vp->text);

		flags |= vp->flags & ~(VTEXTFIXED|VSTACK|VNOSAVE|VUNSET);
	} else {
		if (flags & VNOSET)
			return;
		/* not found */
		vp = ckmalloc(sizeof (*vp));
		vp->next = *vpp;
		vp->func = NULL;
		*vpp = vp;
	}
	if (!(flags & (VTEXTFIXED|VSTACK|VNOSAVE)))
		s = savestr(s);
	vp->text = s;
	vp->flags = flags;
}


/*
 * Process a linked list of variable assignments.
 */

void
listsetvar(struct strlist *list, int flags)
{
	struct strlist *lp;

	lp = list;
	if (!lp)
		return;
	INTOFF;
	do {
		setvareq(lp->text, flags);
	} while ((lp = lp->next));
	INTON;
}


/*
 * Find the value of a variable.  Returns NULL if not set.
 */

char *
lookupvar(const char *name)
{
	struct var *v;

	if ((v = *findvar(hashvar(name), name)) && !(v->flags & VUNSET)) {
		return strchrnul(v->text, '=') + 1;
	}
	return NULL;
}

intmax_t lookupvarint(const char *name)
{
	return atomax(lookupvar(name) ?: nullstr, 0);
}


/*
 * Search the environment of a builtin command.
 */

char *
bltinlookup(const char *name)
{
	struct strlist *sp;

	for (sp = cmdenviron ; sp ; sp = sp->next) {
		if (varequal(sp->text, name))
			return strchrnul(sp->text, '=') + 1;
	}
	return lookupvar(name);
}


/*
 * Generate a list of variables satisfying the given conditions.
 */

char **
listvars(int on, int off, char ***end)
{
	struct var **vpp;
	struct var *vp;
	char **ep;
	int mask;

	STARTSTACKSTR(ep);
	vpp = vartab;
	mask = on | off;
	do {
		for (vp = *vpp ; vp ; vp = vp->next)
			if ((vp->flags & mask) == on) {
				if (ep == stackstrend())
					ep = growstackstr();
				*ep++ = (char *) vp->text;
			}
	} while (++vpp < vartab + VTABSIZE);
	if (ep == stackstrend())
		ep = growstackstr();
	if (end)
		*end = ep;
	*ep++ = NULL;
	return grabstackstr(ep);
}


/*
 * POSIX requires that 'set' (but not export or readonly) output the
 * variables in lexicographic order - by the locale's collating order (sigh).
 * Maybe we could keep them in an ordered balanced binary tree
 * instead of hashed lists.
 * For now just roll 'em through qsort for printing...
 */

int
showvars(const char *prefix, int on, int off)
{
	const char *sep;
	char **ep, **epend;

	ep = listvars(on, off, &epend);
	qsort(ep, epend - ep, sizeof(char *), vpcmp);

	sep = *prefix ? spcstr : prefix;

	for (; ep < epend; ep++) {
		const char *p;
		const char *q;

		p = strchrnul(*ep, '=');
		q = nullstr;
		if (*p)
			q = single_quote(++p);

		out1fmt("%s%s%.*s%s\n", prefix, sep, (int)(p - *ep), *ep, q);
	}

	return 0;
}


/*
 * The export and readonly commands.
 */

int
exportcmd(int argc, char **argv)
{
	struct var *vp;
	char *name;
	const char *p;
	char **aptr;
	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
	int notp;

	notp = nextopt("p") - 'p';
	if (notp && ((name = *(aptr = argptr)))) {
		do {
			if ((p = strchr(name, '=')) != NULL) {
				p++;
			} else {
				if ((vp = *findvar(hashvar(name), name))) {
					vp->flags |= flag;
					continue;
				}
			}
			setvar(name, p, flag);
		} while ((name = *++aptr) != NULL);
	} else {
		showvars(argv[0], flag, 0);
	}
	return 0;
}


/*
 * The "local" command.
 */

int
localcmd(int argc, char **argv)
{
	char *name;

	argv = argptr;
	while ((name = *argv++) != NULL) {
		mklocal(name);
	}
	return 0;
}


/*
 * Make a variable a local variable.  When a variable is made local, it's
 * value and flags are saved in a localvar structure.  The saved values
 * will be restored when the shell function returns.  We handle the name
 * "-" as a special case.
 */

STATIC void
mklocal(char *name)
{
	struct localvar *lvp;
	struct var **vpp;
	struct var *vp;

	INTOFF;
	lvp = ckmalloc(sizeof (struct localvar));
	if (name[0] == '-' && name[1] == '\0') {
		char *p;
		p = ckmalloc(sizeof(optlist));
		lvp->text = memcpy(p, optlist, sizeof(optlist));
		vp = NULL;
	} else {
		char *eq;

		vpp = hashvar(name);
		vp = *findvar(vpp, name);
		eq = strchr(name, '=');
		if (vp == NULL) {
			if (eq)
				setvareq(name, VSTRFIXED);
			else
				setvar(name, NULL, VSTRFIXED);
			vp = *vpp;	/* the new variable */
			lvp->flags = VUNSET;
		} else {
			lvp->text = vp->text;
			lvp->flags = vp->flags;
			vp->flags |= VSTRFIXED|VTEXTFIXED;
			if (eq)
				setvareq(name, 0);
		}
	}
	lvp->vp = vp;
	lvp->next = localvars;
	localvars = lvp;
	INTON;
}


/*
 * Called after a function returns.
 * Interrupts must be off.
 */

void
poplocalvars(void)
{
	struct localvar *lvp;
	struct var *vp;

	while ((lvp = localvars) != NULL) {
		localvars = lvp->next;
		vp = lvp->vp;
		TRACE(("poplocalvar %s", vp ? vp->text : "-"));
		if (vp == NULL) {	/* $- saved */
			memcpy(optlist, lvp->text, sizeof(optlist));
			ckfree(lvp->text);
			optschanged();
		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
			unsetvar(vp->text);
		} else {
			if (vp->func)
				(*vp->func)(strchrnul(lvp->text, '=') + 1);
			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
				ckfree(vp->text);
			vp->flags = lvp->flags;
			vp->text = lvp->text;
		}
		ckfree(lvp);
	}
}


/*
 * The unset builtin command.  We unset the function before we unset the
 * variable to allow a function to be unset when there is a readonly variable
 * with the same name.
 */

int
unsetcmd(int argc, char **argv)
{
	char **ap;
	int i;
	int flag = 0;
	int ret = 0;

	while ((i = nextopt("vf")) != '\0') {
		flag = i;
	}

	for (ap = argptr; *ap ; ap++) {
		if (flag != 'f') {
			i = unsetvar(*ap);
			ret |= i;
			if (!(i & 2))
				continue;
		}
		if (flag != 'v')
			unsetfunc(*ap);
	}
	return ret & 1;
}


/*
 * Unset the specified variable.
 */

int
unsetvar(const char *s)
{
	struct var **vpp;
	struct var *vp;
	int retval;

	vpp = findvar(hashvar(s), s);
	vp = *vpp;
	retval = 2;
	if (vp) {
		int flags = vp->flags;

		retval = 1;
		if (flags & VREADONLY)
			goto out;
		if (flags & VUNSET)
			goto ok;
		if ((flags & VSTRFIXED) == 0) {
			INTOFF;
			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
				ckfree(vp->text);
			*vpp = vp->next;
			ckfree(vp);
			INTON;
		} else {
			setvar(s, 0, 0);
			vp->flags &= ~VEXPORT;
		}
ok:
		retval = 0;
	}

out:
	return retval;
}


/*
 * Find the appropriate entry in the hash table from the name.
 */

STATIC struct var **
hashvar(const char *p)
{
	unsigned int hashval;

	hashval = ((unsigned char) *p) << 4;
	while (*p && *p != '=')
		hashval += (unsigned char) *p++;
	return &vartab[hashval % VTABSIZE];
}


/*
 * Compares two strings up to the first = or '\0'.  The first
 * string must be terminated by '='; the second may be terminated by
 * either '=' or '\0'.
 */

int
varcmp(const char *p, const char *q)
{
	int c, d;

	while ((c = *p) == (d = *q)) {
		if (!c || c == '=')
			goto out;
		p++;
		q++;
	}
	if (c == '=')
		c = 0;
	if (d == '=')
		d = 0;
out:
	return c - d;
}

STATIC int
vpcmp(const void *a, const void *b)
{
	return varcmp(*(const char **)a, *(const char **)b);
}

STATIC struct var **
findvar(struct var **vpp, const char *name)
{
	for (; *vpp; vpp = &(*vpp)->next) {
		if (varequal((*vpp)->text, name)) {
			break;
		}
	}
	return vpp;
}
1	/*-
2	* Copyright (c) 1991, 1993
3	* The Regents of the University of California. All rights reserved.
4	* Copyright (c) 1997-2005
5	* Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved.
6	*
7	* This code is derived from software contributed to Berkeley by
8	* Kenneth Almquist.
9	*
10	* Redistribution and use in source and binary forms, with or without
11	* modification, are permitted provided that the following conditions
12	* are met:
13	* 1. Redistributions of source code must retain the above copyright
14	* notice, this list of conditions and the following disclaimer.
15	* 2. Redistributions in binary form must reproduce the above copyright
16	* notice, this list of conditions and the following disclaimer in the
17	* documentation and/or other materials provided with the distribution.
18	* 3. Neither the name of the University nor the names of its contributors
19	* may be used to endorse or promote products derived from this software
20	* without specific prior written permission.
21	*
22	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32	* SUCH DAMAGE.
33	*/
34
35	#include <unistd.h>
36	#include <stdlib.h>
37	#include <paths.h>
38
39	/*
40	* Shell variables.
41	*/
42
43	#include "shell.h"
44	#include "output.h"
45	#include "expand.h"
46	#include "nodes.h" /* for other headers */
47	#include "eval.h" /* defines cmdenviron */
48	#include "exec.h"
49	#include "syntax.h"
50	#include "options.h"
51	#include "mail.h"
52	#include "var.h"
53	#include "memalloc.h"
54	#include "error.h"
55	#include "mystring.h"
56	#include "parser.h"
57	#include "show.h"
58	#ifndef SMALL
59	#include "myhistedit.h"
60	#endif
61	#include "system.h"
62
63
64	#define VTABSIZE 39
65
66
67	struct localvar *localvars;
68
69	const char defpathvar[] =
70	"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
71	#ifdef IFS_BROKEN
72	const char defifsvar[] = "IFS= \t\n";
73	#else
74	const char defifs[] = " \t\n";
75	#endif
76
77	struct var varinit[] = {
78	#if ATTY
79	{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "ATTY\0", 0 },
80	#endif
81	#ifdef IFS_BROKEN
82	{ 0, VSTRFIXED\|VTEXTFIXED, defifsvar, 0 },
83	#else
84	{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "IFS\0", 0 },
85	#endif
86	{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAIL\0", changemail },
87	{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAILPATH\0", changemail },
88	{ 0, VSTRFIXED\|VTEXTFIXED, defpathvar, changepath },
89	{ 0, VSTRFIXED\|VTEXTFIXED, "PS1=$ ", 0 },
90	{ 0, VSTRFIXED\|VTEXTFIXED, "PS2=> ", 0 },
91	{ 0, VSTRFIXED\|VTEXTFIXED, "PS4=+ ", 0 },
92	{ 0, VSTRFIXED\|VTEXTFIXED, "OPTIND=1", getoptsreset },
93	{ 0, VSTRFIXED\|VTEXTFIXED, "LINENO=1", 0 },
94	#ifndef SMALL
95	{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "TERM\0", 0 },
96	{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "HISTSIZE\0", sethistsize },
97	#endif
98	};
99
100	STATIC struct var *vartab[VTABSIZE];
101
102	STATIC void mklocal(char *);
103	STATIC struct var *hashvar(const char );
104	STATIC int vpcmp(const void , const void );
105	STATIC struct var findvar(struct var , const char *);
106
107	/*
108	* Initialize the varable symbol tables and import the environment
109	*/
110
111	#ifdef mkinit
112	INCLUDE <unistd.h>
113	INCLUDE <sys/types.h>
114	INCLUDE <sys/stat.h>
115	INCLUDE "cd.h"
116	INCLUDE "output.h"
117	INCLUDE "var.h"
118	MKINIT char **environ;
119	INIT {
120	char **envp;
121	static char ppid[32] = "PPID=";
122	const char *p;
123	struct stat st1, st2;
124
125	initvar();
126	for (envp = environ ; *envp ; envp++) {
127	if (strchr(*envp, '=')) {
128	setvareq(*envp, VEXPORT\|VTEXTFIXED);
129	}
130	}
131
132	fmtstr(ppid + 5, sizeof(ppid) - 5, "%ld", (long) getppid());
133	setvareq(ppid, VTEXTFIXED);
134
135	p = lookupvar("PWD");
136	if (p)
137	if (*p != '/' \|\| stat(p, &st1) \|\| stat(".", &st2) \|\|
138	st1.st_dev != st2.st_dev \|\| st1.st_ino != st2.st_ino)
139	p = 0;
140	setpwd(p, 0);
141	}
142	#endif
143
144
145	/*
146	* This routine initializes the builtin variables. It is called when the
147	* shell is initialized.
148	*/
149
150	void
151	initvar(void)
152	{
153	struct var *vp;
154	struct var *end;
155	struct var **vpp;
156
157	vp = varinit;
158	end = vp + sizeof(varinit) / sizeof(varinit[0]);
159	do {
160	vpp = hashvar(vp->text);
161	vp->next = *vpp;
162	*vpp = vp;
163	} while (++vp < end);
164	/*
165	* PS1 depends on uid
166	*/
167	if (!geteuid())
168	vps1.text = "PS1=# ";
169	}
170
171	/*
172	* Set the value of a variable. The flags argument is ored with the
173	* flags of the variable. If val is NULL, the variable is unset.
174	*/
175
176	void
177	setvar(const char name, const char val, int flags)
178	{
179	char p, q;
180	size_t namelen;
181	char *nameeq;
182	size_t vallen;
183
184	q = endofname(name);
185	p = strchrnul(q, '=');
186	namelen = p - name;
187	if (!namelen \|\| p != q)
188	sh_error("%.*s: bad variable name", namelen, name);
189	vallen = 0;
190	if (val == NULL) {
191	flags \|= VUNSET;
192	} else {
193	vallen = strlen(val);
194	}
195	INTOFF;
196	p = mempcpy(nameeq = ckmalloc(namelen + vallen + 2), name, namelen);
197	if (val) {
198	*p++ = '=';
199	p = mempcpy(p, val, vallen);
200	}
201	*p = '\0';
202	setvareq(nameeq, flags \| VNOSAVE);
203	INTON;
204	}
205
206	/*
207	* Set the given integer as the value of a variable. The flags argument is
208	* ored with the flags of the variable.
209	*/
210
211	intmax_t setvarint(const char *name, intmax_t val, int flags)
212	{
213	int len = max_int_length(sizeof(val));
214	char buf[len];
215
216	fmtstr(buf, len, "%jd", val);
217	setvar(name, buf, flags);
218	return val;
219	}
220
221
222
223	/*
224	* Same as setvar except that the variable and value are passed in
225	* the first argument as name=value. Since the first argument will
226	* be actually stored in the table, it should not be a string that
227	* will go away.
228	* Called with interrupts off.
229	*/
230
231	void
232	setvareq(char *s, int flags)
233	{
234	struct var vp, *vpp;
235
236	vpp = hashvar(s);
237	flags \|= (VEXPORT & (((unsigned) (1 - aflag)) - 1));
238	vp = *findvar(vpp, s);
239	if (vp) {
240	if (vp->flags & VREADONLY) {
241	const char *n;
242
243	if (flags & VNOSAVE)
244	free(s);
245	n = vp->text;
246	sh_error("%.*s: is read only", strchrnul(n, '=') - n,
247	n);
248	}
249
250	if (flags & VNOSET)
251	return;
252
253	if (vp->func && (flags & VNOFUNC) == 0)
254	(*vp->func)(strchrnul(s, '=') + 1);
255
256	if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
257	ckfree(vp->text);
258
259	flags \|= vp->flags & ~(VTEXTFIXED\|VSTACK\|VNOSAVE\|VUNSET);
260	} else {
261	if (flags & VNOSET)
262	return;
263	/* not found */
264	vp = ckmalloc(sizeof (*vp));
265	vp->next = *vpp;
266	vp->func = NULL;
267	*vpp = vp;
268	}
269	if (!(flags & (VTEXTFIXED\|VSTACK\|VNOSAVE)))
270	s = savestr(s);
271	vp->text = s;
272	vp->flags = flags;
273	}
274
275
276
277	/*
278	* Process a linked list of variable assignments.
279	*/
280
281	void
282	listsetvar(struct strlist *list, int flags)
283	{
284	struct strlist *lp;
285
286	lp = list;
287	if (!lp)
288	return;
289	INTOFF;
290	do {
291	setvareq(lp->text, flags);
292	} while ((lp = lp->next));
293	INTON;
294	}
295
296
297	/*
298	* Find the value of a variable. Returns NULL if not set.
299	*/
300
301	char *
302	lookupvar(const char *name)
303	{
304	struct var *v;
305
306	if ((v = *findvar(hashvar(name), name)) && !(v->flags & VUNSET)) {
307	return strchrnul(v->text, '=') + 1;
308	}
309	return NULL;
310	}
311
312	intmax_t lookupvarint(const char *name)
313	{
314	return atomax(lookupvar(name) ?: nullstr, 0);
315	}
316
317
318
319	/*
320	* Search the environment of a builtin command.
321	*/
322
323	char *
324	bltinlookup(const char *name)
325	{
326	struct strlist *sp;
327
328	for (sp = cmdenviron ; sp ; sp = sp->next) {
329	if (varequal(sp->text, name))
330	return strchrnul(sp->text, '=') + 1;
331	}
332	return lookupvar(name);
333	}
334
335
336
337	/*
338	* Generate a list of variables satisfying the given conditions.
339	*/
340
341	char **
342	listvars(int on, int off, char ***end)
343	{
344	struct var **vpp;
345	struct var *vp;
346	char **ep;
347	int mask;
348
349	STARTSTACKSTR(ep);
350	vpp = vartab;
351	mask = on \| off;
352	do {
353	for (vp = *vpp ; vp ; vp = vp->next)
354	if ((vp->flags & mask) == on) {
355	if (ep == stackstrend())
356	ep = growstackstr();
357	ep++ = (char ) vp->text;
358	}
359	} while (++vpp < vartab + VTABSIZE);
360	if (ep == stackstrend())
361	ep = growstackstr();
362	if (end)
363	*end = ep;
364	*ep++ = NULL;
365	return grabstackstr(ep);
366	}
367
368
369
370	/*
371	* POSIX requires that 'set' (but not export or readonly) output the
372	* variables in lexicographic order - by the locale's collating order (sigh).
373	* Maybe we could keep them in an ordered balanced binary tree
374	* instead of hashed lists.
375	* For now just roll 'em through qsort for printing...
376	*/
377
378	int
379	showvars(const char *prefix, int on, int off)
380	{
381	const char *sep;
382	char ep, epend;
383
384	ep = listvars(on, off, &epend);
385	qsort(ep, epend - ep, sizeof(char *), vpcmp);
386
387	sep = *prefix ? spcstr : prefix;
388
389	for (; ep < epend; ep++) {
390	const char *p;
391	const char *q;
392
393	p = strchrnul(*ep, '=');
394	q = nullstr;
395	if (*p)
396	q = single_quote(++p);
397
398	out1fmt("%s%s%.s%s\n", prefix, sep, (int)(p - ep), *ep, q);
399	}
400
401	return 0;
402	}
403
404
405
406	/*
407	* The export and readonly commands.
408	*/
409
410	int
411	exportcmd(int argc, char **argv)
412	{
413	struct var *vp;
414	char *name;
415	const char *p;
416	char **aptr;
417	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
418	int notp;
419
420	notp = nextopt("p") - 'p';
421	if (notp && ((name = *(aptr = argptr)))) {
422	do {
423	if ((p = strchr(name, '=')) != NULL) {
424	p++;
425	} else {
426	if ((vp = *findvar(hashvar(name), name))) {
427	vp->flags \|= flag;
428	continue;
429	}
430	}
431	setvar(name, p, flag);
432	} while ((name = *++aptr) != NULL);
433	} else {
434	showvars(argv[0], flag, 0);
435	}
436	return 0;
437	}
438
439
440	/*
441	* The "local" command.
442	*/
443
444	int
445	localcmd(int argc, char **argv)
446	{
447	char *name;
448
449	argv = argptr;
450	while ((name = *argv++) != NULL) {
451	mklocal(name);
452	}
453	return 0;
454	}
455
456
457	/*
458	* Make a variable a local variable. When a variable is made local, it's
459	* value and flags are saved in a localvar structure. The saved values
460	* will be restored when the shell function returns. We handle the name
461	* "-" as a special case.
462	*/
463
464	STATIC void
465	mklocal(char *name)
466	{
467	struct localvar *lvp;
468	struct var **vpp;
469	struct var *vp;
470
471	INTOFF;
472	lvp = ckmalloc(sizeof (struct localvar));
473	if (name[0] == '-' && name[1] == '\0') {
474	char *p;
475	p = ckmalloc(sizeof(optlist));
476	lvp->text = memcpy(p, optlist, sizeof(optlist));
477	vp = NULL;
478	} else {
479	char *eq;
480
481	vpp = hashvar(name);
482	vp = *findvar(vpp, name);
483	eq = strchr(name, '=');
484	if (vp == NULL) {
485	if (eq)
486	setvareq(name, VSTRFIXED);
487	else
488	setvar(name, NULL, VSTRFIXED);
489	vp = vpp; / the new variable */
490	lvp->flags = VUNSET;
491	} else {
492	lvp->text = vp->text;
493	lvp->flags = vp->flags;
494	vp->flags \|= VSTRFIXED\|VTEXTFIXED;
495	if (eq)
496	setvareq(name, 0);
497	}
498	}
499	lvp->vp = vp;
500	lvp->next = localvars;
501	localvars = lvp;
502	INTON;
503	}
504
505
506	/*
507	* Called after a function returns.
508	* Interrupts must be off.
509	*/
510
511	void
512	poplocalvars(void)
513	{
514	struct localvar *lvp;
515	struct var *vp;
516
517	while ((lvp = localvars) != NULL) {
518	localvars = lvp->next;
519	vp = lvp->vp;
520	TRACE(("poplocalvar %s", vp ? vp->text : "-"));
521	if (vp == NULL) { /* $- saved */
522	memcpy(optlist, lvp->text, sizeof(optlist));
523	ckfree(lvp->text);
524	optschanged();
525	} else if ((lvp->flags & (VUNSET\|VSTRFIXED)) == VUNSET) {
526	unsetvar(vp->text);
527	} else {
528	if (vp->func)
529	(*vp->func)(strchrnul(lvp->text, '=') + 1);
530	if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
531	ckfree(vp->text);
532	vp->flags = lvp->flags;
533	vp->text = lvp->text;
534	}
535	ckfree(lvp);
536	}
537	}
538
539
540	/*
541	* The unset builtin command. We unset the function before we unset the
542	* variable to allow a function to be unset when there is a readonly variable
543	* with the same name.
544	*/
545
546	int
547	unsetcmd(int argc, char **argv)
548	{
549	char **ap;
550	int i;
551	int flag = 0;
552	int ret = 0;
553
554	while ((i = nextopt("vf")) != '\0') {
555	flag = i;
556	}
557
558	for (ap = argptr; *ap ; ap++) {
559	if (flag != 'f') {
560	i = unsetvar(*ap);
561	ret \|= i;
562	if (!(i & 2))
563	continue;
564	}
565	if (flag != 'v')
566	unsetfunc(*ap);
567	}
568	return ret & 1;
569	}
570
571
572	/*
573	* Unset the specified variable.
574	*/
575
576	int
577	unsetvar(const char *s)
578	{
579	struct var **vpp;
580	struct var *vp;
581	int retval;
582
583	vpp = findvar(hashvar(s), s);
584	vp = *vpp;
585	retval = 2;
586	if (vp) {
587	int flags = vp->flags;
588
589	retval = 1;
590	if (flags & VREADONLY)
591	goto out;
592	if (flags & VUNSET)
593	goto ok;
594	if ((flags & VSTRFIXED) == 0) {
595	INTOFF;
596	if ((flags & (VTEXTFIXED\|VSTACK)) == 0)
597	ckfree(vp->text);
598	*vpp = vp->next;
599	ckfree(vp);
600	INTON;
601	} else {
602	setvar(s, 0, 0);
603	vp->flags &= ~VEXPORT;
604	}
605	ok:
606	retval = 0;
607	}
608
609	out:
610	return retval;
611	}
612
613
614
615	/*
616	* Find the appropriate entry in the hash table from the name.
617	*/
618
619	STATIC struct var **
620	hashvar(const char *p)
621	{
622	unsigned int hashval;
623
624	hashval = ((unsigned char) *p) << 4;
625	while (p && p != '=')
626	hashval += (unsigned char) *p++;
627	return &vartab[hashval % VTABSIZE];
628	}
629
630
631
632	/*
633	* Compares two strings up to the first = or '\0'. The first
634	* string must be terminated by '='; the second may be terminated by
635	* either '=' or '\0'.
636	*/
637
638	int
639	varcmp(const char p, const char q)
640	{
641	int c, d;
642
643	while ((c = p) == (d = q)) {
644	if (!c \|\| c == '=')
645	goto out;
646	p++;
647	q++;
648	}
649	if (c == '=')
650	c = 0;
651	if (d == '=')
652	d = 0;
653	out:
654	return c - d;
655	}
656
657	STATIC int
658	vpcmp(const void a, const void b)
659	{
660	return varcmp((const char )a, (const char **)b);
661	}
662
663	STATIC struct var **
664	findvar(struct var *vpp, const char name)
665	{
666	for (; vpp; vpp = &(vpp)->next) {
667	if (varequal((*vpp)->text, name)) {
668	break;
669	}
670	}
671	return vpp;
672	}