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 },
#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=# ";
}

/*
 * Safe version of setvar, returns 1 on success 0 on failure.
 */

int
setvarsafe(const char *name, const char *val, int flags)
{
	int err;
	volatile int saveint;
	struct jmploc *volatile savehandler = handler;
	struct jmploc jmploc;

	SAVEINT(saveint);
	if (setjmp(jmploc.loc))
		err = 1;
	else {
		handler = &jmploc;
		setvar(name, val, flags);
		err = 0;
	}
	handler = savehandler;
	RESTOREINT(saveint);
	return err;
}

/*
 * 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;
}


/*
 * 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;
}


/*
 * 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	niro	532	/*-
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			#ifndef SMALL
94			{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "TERM\0", 0 },
95			{ 0, VSTRFIXED\|VTEXTFIXED\|VUNSET, "HISTSIZE\0", sethistsize },
96			#endif
97			};
98
99			STATIC struct var *vartab[VTABSIZE];
100
101			STATIC void mklocal(char *);
102			STATIC struct var *hashvar(const char );
103			STATIC int vpcmp(const void , const void );
104			STATIC struct var findvar(struct var , const char *);
105
106			/*
107			* Initialize the varable symbol tables and import the environment
108			*/
109
110			#ifdef mkinit
111			INCLUDE <unistd.h>
112			INCLUDE <sys/types.h>
113			INCLUDE <sys/stat.h>
114			INCLUDE "cd.h"
115			INCLUDE "output.h"
116			INCLUDE "var.h"
117			MKINIT char **environ;
118			INIT {
119			char **envp;
120			static char ppid[32] = "PPID=";
121			const char *p;
122			struct stat st1, st2;
123
124			initvar();
125			for (envp = environ ; *envp ; envp++) {
126			if (strchr(*envp, '=')) {
127			setvareq(*envp, VEXPORT\|VTEXTFIXED);
128			}
129			}
130
131			fmtstr(ppid + 5, sizeof(ppid) - 5, "%ld", (long) getppid());
132			setvareq(ppid, VTEXTFIXED);
133
134			p = lookupvar("PWD");
135			if (p)
136			if (*p != '/' \|\| stat(p, &st1) \|\| stat(".", &st2) \|\|
137			st1.st_dev != st2.st_dev \|\| st1.st_ino != st2.st_ino)
138			p = 0;
139			setpwd(p, 0);
140			}
141			#endif
142
143
144			/*
145			* This routine initializes the builtin variables. It is called when the
146			* shell is initialized.
147			*/
148
149			void
150			initvar(void)
151			{
152			struct var *vp;
153			struct var *end;
154			struct var **vpp;
155
156			vp = varinit;
157			end = vp + sizeof(varinit) / sizeof(varinit[0]);
158			do {
159			vpp = hashvar(vp->text);
160			vp->next = *vpp;
161			*vpp = vp;
162			} while (++vp < end);
163			/*
164			* PS1 depends on uid
165			*/
166			if (!geteuid())
167			vps1.text = "PS1=# ";
168			}
169
170			/*
171			* Safe version of setvar, returns 1 on success 0 on failure.
172			*/
173
174			int
175			setvarsafe(const char name, const char val, int flags)
176			{
177			int err;
178			volatile int saveint;
179			struct jmploc *volatile savehandler = handler;
180			struct jmploc jmploc;
181
182			SAVEINT(saveint);
183			if (setjmp(jmploc.loc))
184			err = 1;
185			else {
186			handler = &jmploc;
187			setvar(name, val, flags);
188			err = 0;
189			}
190			handler = savehandler;
191			RESTOREINT(saveint);
192			return err;
193			}
194
195			/*
196			* Set the value of a variable. The flags argument is ored with the
197			* flags of the variable. If val is NULL, the variable is unset.
198			*/
199
200			void
201			setvar(const char name, const char val, int flags)
202			{
203			char p, q;
204			size_t namelen;
205			char *nameeq;
206			size_t vallen;
207
208			q = endofname(name);
209			p = strchrnul(q, '=');
210			namelen = p - name;
211			if (!namelen \|\| p != q)
212			sh_error("%.*s: bad variable name", namelen, name);
213			vallen = 0;
214			if (val == NULL) {
215			flags \|= VUNSET;
216			} else {
217			vallen = strlen(val);
218			}
219			INTOFF;
220			p = mempcpy(nameeq = ckmalloc(namelen + vallen + 2), name, namelen);
221			if (val) {
222			*p++ = '=';
223			p = mempcpy(p, val, vallen);
224			}
225			*p = '\0';
226			setvareq(nameeq, flags \| VNOSAVE);
227			INTON;
228			}
229
230
231
232			/*
233			* Same as setvar except that the variable and value are passed in
234			* the first argument as name=value. Since the first argument will
235			* be actually stored in the table, it should not be a string that
236			* will go away.
237			* Called with interrupts off.
238			*/
239
240			void
241			setvareq(char *s, int flags)
242			{
243			struct var vp, *vpp;
244
245			vpp = hashvar(s);
246			flags \|= (VEXPORT & (((unsigned) (1 - aflag)) - 1));
247			vp = *findvar(vpp, s);
248			if (vp) {
249			if (vp->flags & VREADONLY) {
250			const char *n;
251
252			if (flags & VNOSAVE)
253			free(s);
254			n = vp->text;
255			sh_error("%.*s: is read only", strchrnul(n, '=') - n,
256			n);
257			}
258
259			if (flags & VNOSET)
260			return;
261
262			if (vp->func && (flags & VNOFUNC) == 0)
263			(*vp->func)(strchrnul(s, '=') + 1);
264
265			if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
266			ckfree(vp->text);
267
268			flags \|= vp->flags & ~(VTEXTFIXED\|VSTACK\|VNOSAVE\|VUNSET);
269			} else {
270			if (flags & VNOSET)
271			return;
272			/* not found */
273			vp = ckmalloc(sizeof (*vp));
274			vp->next = *vpp;
275			vp->func = NULL;
276			*vpp = vp;
277			}
278			if (!(flags & (VTEXTFIXED\|VSTACK\|VNOSAVE)))
279			s = savestr(s);
280			vp->text = s;
281			vp->flags = flags;
282			}
283
284
285
286			/*
287			* Process a linked list of variable assignments.
288			*/
289
290			void
291			listsetvar(struct strlist *list, int flags)
292			{
293			struct strlist *lp;
294
295			lp = list;
296			if (!lp)
297			return;
298			INTOFF;
299			do {
300			setvareq(lp->text, flags);
301			} while ((lp = lp->next));
302			INTON;
303			}
304
305
306			/*
307			* Find the value of a variable. Returns NULL if not set.
308			*/
309
310			char *
311			lookupvar(const char *name)
312			{
313			struct var *v;
314
315			if ((v = *findvar(hashvar(name), name)) && !(v->flags & VUNSET)) {
316			return strchrnul(v->text, '=') + 1;
317			}
318			return NULL;
319			}
320
321
322
323			/*
324			* Search the environment of a builtin command.
325			*/
326
327			char *
328			bltinlookup(const char *name)
329			{
330			struct strlist *sp;
331
332			for (sp = cmdenviron ; sp ; sp = sp->next) {
333			if (varequal(sp->text, name))
334			return strchrnul(sp->text, '=') + 1;
335			}
336			return lookupvar(name);
337			}
338
339
340
341			/*
342			* Generate a list of variables satisfying the given conditions.
343			*/
344
345			char **
346			listvars(int on, int off, char ***end)
347			{
348			struct var **vpp;
349			struct var *vp;
350			char **ep;
351			int mask;
352
353			STARTSTACKSTR(ep);
354			vpp = vartab;
355			mask = on \| off;
356			do {
357			for (vp = *vpp ; vp ; vp = vp->next)
358			if ((vp->flags & mask) == on) {
359			if (ep == stackstrend())
360			ep = growstackstr();
361			ep++ = (char ) vp->text;
362			}
363			} while (++vpp < vartab + VTABSIZE);
364			if (ep == stackstrend())
365			ep = growstackstr();
366			if (end)
367			*end = ep;
368			*ep++ = NULL;
369			return grabstackstr(ep);
370			}
371
372
373
374			/*
375			* POSIX requires that 'set' (but not export or readonly) output the
376			* variables in lexicographic order - by the locale's collating order (sigh).
377			* Maybe we could keep them in an ordered balanced binary tree
378			* instead of hashed lists.
379			* For now just roll 'em through qsort for printing...
380			*/
381
382			int
383			showvars(const char *prefix, int on, int off)
384			{
385			const char *sep;
386			char ep, epend;
387
388			ep = listvars(on, off, &epend);
389			qsort(ep, epend - ep, sizeof(char *), vpcmp);
390
391			sep = *prefix ? spcstr : prefix;
392
393			for (; ep < epend; ep++) {
394			const char *p;
395			const char *q;
396
397			p = strchrnul(*ep, '=');
398			q = nullstr;
399			if (*p)
400			q = single_quote(++p);
401
402			out1fmt("%s%s%.s%s\n", prefix, sep, (int)(p - ep), *ep, q);
403			}
404
405			return 0;
406			}
407
408
409
410			/*
411			* The export and readonly commands.
412			*/
413
414			int
415			exportcmd(int argc, char **argv)
416			{
417			struct var *vp;
418			char *name;
419			const char *p;
420			char **aptr;
421			int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
422			int notp;
423
424			notp = nextopt("p") - 'p';
425			if (notp && ((name = *(aptr = argptr)))) {
426			do {
427			if ((p = strchr(name, '=')) != NULL) {
428			p++;
429			} else {
430			if ((vp = *findvar(hashvar(name), name))) {
431			vp->flags \|= flag;
432			continue;
433			}
434			}
435			setvar(name, p, flag);
436			} while ((name = *++aptr) != NULL);
437			} else {
438			showvars(argv[0], flag, 0);
439			}
440			return 0;
441			}
442
443
444			/*
445			* The "local" command.
446			*/
447
448			int
449			localcmd(int argc, char **argv)
450			{
451			char *name;
452
453			argv = argptr;
454			while ((name = *argv++) != NULL) {
455			mklocal(name);
456			}
457			return 0;
458			}
459
460
461			/*
462			* Make a variable a local variable. When a variable is made local, it's
463			* value and flags are saved in a localvar structure. The saved values
464			* will be restored when the shell function returns. We handle the name
465			* "-" as a special case.
466			*/
467
468			STATIC void
469			mklocal(char *name)
470			{
471			struct localvar *lvp;
472			struct var **vpp;
473			struct var *vp;
474
475			INTOFF;
476			lvp = ckmalloc(sizeof (struct localvar));
477			if (name[0] == '-' && name[1] == '\0') {
478			char *p;
479			p = ckmalloc(sizeof(optlist));
480			lvp->text = memcpy(p, optlist, sizeof(optlist));
481			vp = NULL;
482			} else {
483			char *eq;
484
485			vpp = hashvar(name);
486			vp = *findvar(vpp, name);
487			eq = strchr(name, '=');
488			if (vp == NULL) {
489			if (eq)
490			setvareq(name, VSTRFIXED);
491			else
492			setvar(name, NULL, VSTRFIXED);
493			vp = vpp; / the new variable */
494			lvp->flags = VUNSET;
495			} else {
496			lvp->text = vp->text;
497			lvp->flags = vp->flags;
498			vp->flags \|= VSTRFIXED\|VTEXTFIXED;
499			if (eq)
500			setvareq(name, 0);
501			}
502			}
503			lvp->vp = vp;
504			lvp->next = localvars;
505			localvars = lvp;
506			INTON;
507			}
508
509
510			/*
511			* Called after a function returns.
512			* Interrupts must be off.
513			*/
514
515			void
516			poplocalvars(void)
517			{
518			struct localvar *lvp;
519			struct var *vp;
520
521			while ((lvp = localvars) != NULL) {
522			localvars = lvp->next;
523			vp = lvp->vp;
524			TRACE(("poplocalvar %s", vp ? vp->text : "-"));
525			if (vp == NULL) { /* $- saved */
526			memcpy(optlist, lvp->text, sizeof(optlist));
527			ckfree(lvp->text);
528			optschanged();
529			} else if ((lvp->flags & (VUNSET\|VSTRFIXED)) == VUNSET) {
530			unsetvar(vp->text);
531			} else {
532			if (vp->func)
533			(*vp->func)(strchrnul(lvp->text, '=') + 1);
534			if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
535			ckfree(vp->text);
536			vp->flags = lvp->flags;
537			vp->text = lvp->text;
538			}
539			ckfree(lvp);
540			}
541			}
542
543
544			/*
545			* The unset builtin command. We unset the function before we unset the
546			* variable to allow a function to be unset when there is a readonly variable
547			* with the same name.
548			*/
549
550			int
551			unsetcmd(int argc, char **argv)
552			{
553			char **ap;
554			int i;
555			int flag = 0;
556			int ret = 0;
557
558			while ((i = nextopt("vf")) != '\0') {
559			flag = i;
560			}
561
562			for (ap = argptr; *ap ; ap++) {
563			if (flag != 'f') {
564			i = unsetvar(*ap);
565			ret \|= i;
566			if (!(i & 2))
567			continue;
568			}
569			if (flag != 'v')
570			unsetfunc(*ap);
571			}
572			return ret & 1;
573			}
574
575
576			/*
577			* Unset the specified variable.
578			*/
579
580			int
581			unsetvar(const char *s)
582			{
583			struct var **vpp;
584			struct var *vp;
585			int retval;
586
587			vpp = findvar(hashvar(s), s);
588			vp = *vpp;
589			retval = 2;
590			if (vp) {
591			int flags = vp->flags;
592
593			retval = 1;
594			if (flags & VREADONLY)
595			goto out;
596			if (flags & VUNSET)
597			goto ok;
598			if ((flags & VSTRFIXED) == 0) {
599			INTOFF;
600			if ((flags & (VTEXTFIXED\|VSTACK)) == 0)
601			ckfree(vp->text);
602			*vpp = vp->next;
603			ckfree(vp);
604			INTON;
605			} else {
606			setvar(s, 0, 0);
607			vp->flags &= ~VEXPORT;
608			}
609			ok:
610			retval = 0;
611			}
612
613			out:
614			return retval;
615			}
616
617
618
619			/*
620			* Find the appropriate entry in the hash table from the name.
621			*/
622
623			STATIC struct var **
624			hashvar(const char *p)
625			{
626			unsigned int hashval;
627
628			hashval = ((unsigned char) *p) << 4;
629			while (p && p != '=')
630			hashval += (unsigned char) *p++;
631			return &vartab[hashval % VTABSIZE];
632			}
633
634
635
636			/*
637			* Compares two strings up to the first = or '\0'. The first
638			* string must be terminated by '='; the second may be terminated by
639			* either '=' or '\0'.
640			*/
641
642			int
643			varcmp(const char p, const char q)
644			{
645			int c, d;
646
647			while ((c = p) == (d = q)) {
648			if (!c \|\| c == '=')
649			goto out;
650			p++;
651			q++;
652			}
653			if (c == '=')
654			c = 0;
655			if (d == '=')
656			d = 0;
657			out:
658			return c - d;
659			}
660
661			STATIC int
662			vpcmp(const void a, const void b)
663			{
664			return varcmp((const char )a, (const char **)b);
665			}
666
667			STATIC struct var **
668			findvar(struct var *vpp, const char name)
669			{
670			for (; vpp; vpp = &(vpp)->next) {
671			if (varequal((*vpp)->text, name)) {
672			break;
673			}
674			}
675			return vpp;
676			}