[unix-history] / bin / sh / var.c

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static char sccsid[] = "@(#)var.c	5.3 (Berkeley) 4/12/91";
#endif /* not lint */

/*
 * 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"


#define VTABSIZE 39


struct varinit {
	struct var *var;
	int flags;
	char *text;
};


#if ATTY
struct var vatty;
#endif
struct var vifs;
struct var vmail;
struct var vmpath;
struct var vpath;
struct var vps1;
struct var vps2;
struct var vvers;
#if ATTY
struct var vterm;
#endif

const struct varinit varinit[] = {
#if ATTY
	{&vatty,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY="},
#endif
	{&vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n"},
	{&vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL="},
	{&vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH="},
	{&vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=:/bin:/usr/bin"},
	/* 
	 * vps1 depends on uid
	 */
	{&vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> "},
#if ATTY
	{&vterm,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM="},
#endif
	{NULL,	0,				NULL}
};

struct var *vartab[VTABSIZE];

STATIC void unsetvar __P((char *));
STATIC struct var **hashvar __P((char *));
STATIC int varequal __P((char *, char *));

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

#ifdef mkinit
INCLUDE "var.h"
INIT {
	char **envp;
	extern char **environ;

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


/*
 * This routine initializes the builtin variables.  It is called when the
 * shell is initialized and again when a shell procedure is spawned.
 */

void
initvar() {
	const struct varinit *ip;
	struct var *vp;
	struct var **vpp;

	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
		if ((vp->flags & VEXPORT) == 0) {
			vpp = hashvar(ip->text);
			vp->next = *vpp;
			*vpp = vp;
			vp->text = ip->text;
			vp->flags = ip->flags;
		}
	}
	/*
	 * PS1 depends on uid
	 */
	if ((vps1.flags & VEXPORT) == 0) {
		vpp = hashvar("PS1=");
		vps1.next = *vpp;
		*vpp = &vps1;
		vps1.text = getuid() ? "PS1=$ " : "PS1=# ";
		vps1.flags = VSTRFIXED|VTEXTFIXED;
	}
}

/*
 * 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(name, val, flags)
	char *name, *val;
	{
	char *p, *q;
	int len;
	int namelen;
	char *nameeq;
	int isbad;

	isbad = 0;
	p = name;
	if (! is_name(*p++))
		isbad = 1;
	for (;;) {
		if (! is_in_name(*p)) {
			if (*p == '\0' || *p == '=')
				break;
			isbad = 1;
		}
		p++;
	}
	namelen = p - name;
	if (isbad)
		error("%.*s: is read only", namelen, name);
	len = namelen + 2;		/* 2 is space for '=' and '\0' */
	if (val == NULL) {
		flags |= VUNSET;
	} else {
		len += strlen(val);
	}
	p = nameeq = ckmalloc(len);
	q = name;
	while (--namelen >= 0)
		*p++ = *q++;
	*p++ = '=';
	*p = '\0';
	if (val)
		scopy(val, p);
	setvareq(nameeq, flags);
}


/*
 * 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.
 */

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

	vpp = hashvar(s);
	for (vp = *vpp ; vp ; vp = vp->next) {
		if (varequal(s, vp->text)) {
			if (vp->flags & VREADONLY) {
				int len = strchr(s, '=') - s;
				error("%.*s: is read only", len, s);
			}
			INTOFF;
			if (vp == &vpath)
				changepath(s + 5);	/* 5 = strlen("PATH=") */
			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
				ckfree(vp->text);
			vp->flags &=~ (VTEXTFIXED|VSTACK|VUNSET);
			vp->flags |= flags;
			vp->text = s;
			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
				chkmail(1);
			INTON;
			return;
		}
	}
	/* not found */
	vp = ckmalloc(sizeof (*vp));
	vp->flags = flags;
	vp->text = s;
	vp->next = *vpp;
	*vpp = vp;
}


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

void
listsetvar(list)
	struct strlist *list;
	{
	struct strlist *lp;

	INTOFF;
	for (lp = list ; lp ; lp = lp->next) {
		setvareq(savestr(lp->text), 0);
	}
	INTON;
}


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

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

	for (v = *hashvar(name) ; v ; v = v->next) {
		if (varequal(v->text, name)) {
			if (v->flags & VUNSET)
				return NULL;
			return strchr(v->text, '=') + 1;
		}
	}
	return NULL;
}


/*
 * Search the environment of a builtin command.  If the second argument
 * is nonzero, return the value of a variable even if it hasn't been
 * exported.
 */

char *
bltinlookup(name, doall)
	char *name;
	{
	struct strlist *sp;
	struct var *v;

	for (sp = cmdenviron ; sp ; sp = sp->next) {
		if (varequal(sp->text, name))
			return strchr(sp->text, '=') + 1;
	}
	for (v = *hashvar(name) ; v ; v = v->next) {
		if (varequal(v->text, name)) {
			if (v->flags & VUNSET
			 || ! doall && (v->flags & VEXPORT) == 0)
				return NULL;
			return strchr(v->text, '=') + 1;
		}
	}
	return NULL;
}


/*
 * Generate a list of exported variables.  This routine is used to construct
 * the third argument to execve when executing a program.
 */

char **
environment() {
	int nenv;
	struct var **vpp;
	struct var *vp;
	char **env, **ep;

	nenv = 0;
	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
		for (vp = *vpp ; vp ; vp = vp->next)
			if (vp->flags & VEXPORT)
				nenv++;
	}
	ep = env = stalloc((nenv + 1) * sizeof *env);
	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
		for (vp = *vpp ; vp ; vp = vp->next)
			if (vp->flags & VEXPORT)
				*ep++ = vp->text;
	}
	*ep = NULL;
	return env;
}


/*
 * Called when a shell procedure is invoked to clear out nonexported
 * variables.  It is also necessary to reallocate variables of with
 * VSTACK set since these are currently allocated on the stack.
 */

#ifdef mkinit
MKINIT void shprocvar();

SHELLPROC {
	shprocvar();
}
#endif

void
shprocvar() {
	struct var **vpp;
	struct var *vp, **prev;

	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
		for (prev = vpp ; (vp = *prev) != NULL ; ) {
			if ((vp->flags & VEXPORT) == 0) {
				*prev = vp->next;
				if ((vp->flags & VTEXTFIXED) == 0)
					ckfree(vp->text);
				if ((vp->flags & VSTRFIXED) == 0)
					ckfree(vp);
			} else {
				if (vp->flags & VSTACK) {
					vp->text = savestr(vp->text);
					vp->flags &=~ VSTACK;
				}
				prev = &vp->next;
			}
		}
	}
	initvar();
}


/*
 * Command to list all variables which are set.  Currently this command
 * is invoked from the set command when the set command is called without
 * any variables.
 */

int
showvarscmd(argc, argv)  char **argv; {
	struct var **vpp;
	struct var *vp;

	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
		for (vp = *vpp ; vp ; vp = vp->next) {
			if ((vp->flags & VUNSET) == 0)
				out1fmt("%s\n", vp->text);
		}
	}
	return 0;
}


/*
 * The export and readonly commands.
 */

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

	listsetvar(cmdenviron);
	if (argc > 1) {
		while ((name = *argptr++) != NULL) {
			if ((p = strchr(name, '=')) != NULL) {
				p++;
			} else {
				vpp = hashvar(name);
				for (vp = *vpp ; vp ; vp = vp->next) {
					if (varequal(vp->text, name)) {
						vp->flags |= flag;
						goto found;
					}
				}
			}
			setvar(name, p, flag);
found:;
		}
	} else {
		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
			for (vp = *vpp ; vp ; vp = vp->next) {
				if (vp->flags & flag) {
					for (p = vp->text ; *p != '=' ; p++)
						out1c(*p);
					out1c('\n');
				}
			}
		}
	}
	return 0;
}


/*
 * The "local" command.
 */

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

	if (! in_function())
		error("Not in a function");
	while ((name = *argptr++) != 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.
 */

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

	INTOFF;
	lvp = ckmalloc(sizeof (struct localvar));
	if (name[0] == '-' && name[1] == '\0') {
		lvp->text = ckmalloc(sizeof optval);
		bcopy(optval, lvp->text, sizeof optval);
		vp = NULL;
	} else {
		vpp = hashvar(name);
		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
		if (vp == NULL) {
			if (strchr(name, '='))
				setvareq(savestr(name), VSTRFIXED);
			else
				setvar(name, NULL, VSTRFIXED);
			vp = *vpp;	/* the new variable */
			lvp->text = NULL;
			lvp->flags = VUNSET;
		} else {
			lvp->text = vp->text;
			lvp->flags = vp->flags;
			vp->flags |= VSTRFIXED|VTEXTFIXED;
			if (strchr(name, '='))
				setvareq(savestr(name), 0);
		}
	}
	lvp->vp = vp;
	lvp->next = localvars;
	localvars = lvp;
	INTON;
}


/*
 * Called after a function returns.
 */

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

	while ((lvp = localvars) != NULL) {
		localvars = lvp->next;
		vp = lvp->vp;
		if (vp == NULL) {	/* $- saved */
			bcopy(lvp->text, optval, sizeof optval);
			ckfree(lvp->text);
		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
			unsetvar(vp->text);
		} else {
			if ((vp->flags & VTEXTFIXED) == 0)
				ckfree(vp->text);
			vp->flags = lvp->flags;
			vp->text = lvp->text;
		}
		ckfree(lvp);
	}
}


setvarcmd(argc, argv)  char **argv; {
	if (argc <= 2)
		return unsetcmd(argc, argv);
	else if (argc == 3)
		setvar(argv[1], argv[2], 0);
	else
		error("List assignment not implemented");
	return 0;
}


/*
 * 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.
 */

unsetcmd(argc, argv)  char **argv; {
	char **ap;

	for (ap = argv + 1 ; *ap ; ap++) {
		unsetfunc(*ap);
		unsetvar(*ap);
	}
	return 0;
}


/*
 * Unset the specified variable.
 */

STATIC void
unsetvar(s)
	char *s;
	{
	struct var **vpp;
	struct var *vp;

	vpp = hashvar(s);
	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
		if (varequal(vp->text, s)) {
			INTOFF;
			if (*(strchr(vp->text, '=') + 1) != '\0'
			 || vp->flags & VREADONLY) {
				setvar(s, nullstr, 0);
			}
			vp->flags &=~ VEXPORT;
			vp->flags |= VUNSET;
			if ((vp->flags & VSTRFIXED) == 0) {
				if ((vp->flags & VTEXTFIXED) == 0)
					ckfree(vp->text);
				*vpp = vp->next;
				ckfree(vp);
			}
			INTON;
			return;
		}
	}
}


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

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

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


/*
 * Returns true if the two strings specify the same varable.  The first
 * variable name is terminated by '='; the second may be terminated by
 * either '=' or '\0'.
 */

STATIC int
varequal(p, q)
	register char *p, *q;
	{
	while (*p == *q++) {
		if (*p++ == '=')
			return 1;
	}
	if (*p == '=' && *(q - 1) == '\0')
		return 1;
	return 0;
}
Commit	Line	Data
15637ed4 RG	1	/*-
	2	* Copyright (c) 1991 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Kenneth Almquist.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*/
	36
	37	#ifndef lint
	38	static char sccsid[] = "@(#)var.c 5.3 (Berkeley) 4/12/91";
	39	#endif /* not lint */
	40
	41	/*
	42	* Shell variables.
	43	*/
	44
	45	#include "shell.h"
	46	#include "output.h"
	47	#include "expand.h"
	48	#include "nodes.h" /* for other headers */
	49	#include "eval.h" /* defines cmdenviron */
	50	#include "exec.h"
	51	#include "syntax.h"
	52	#include "options.h"
	53	#include "mail.h"
	54	#include "var.h"
	55	#include "memalloc.h"
	56	#include "error.h"
	57	#include "mystring.h"
	58
	59
	60	#define VTABSIZE 39
	61
	62
	63	struct varinit {
	64	struct var *var;
65	int flags;
66	char *text;
67	};
68
69
70	#if ATTY
71	struct var vatty;
72	#endif
73	struct var vifs;
74	struct var vmail;
75	struct var vmpath;
76	struct var vpath;
77	struct var vps1;
78	struct var vps2;
79	struct var vvers;
80	#if ATTY
81	struct var vterm;
82	#endif
83
84	const struct varinit varinit[] = {
85	#if ATTY
86	{&vatty, VSTRFIXED\|VTEXTFIXED\|VUNSET, "ATTY="},
87	#endif
88	{&vifs, VSTRFIXED\|VTEXTFIXED, "IFS= \t\n"},
89	{&vmail, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAIL="},
90	{&vmpath, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAILPATH="},
91	{&vpath, VSTRFIXED\|VTEXTFIXED, "PATH=:/bin:/usr/bin"},
92	/*
93	* vps1 depends on uid
94	*/
95	{&vps2, VSTRFIXED\|VTEXTFIXED, "PS2=> "},
96	#if ATTY
97	{&vterm, VSTRFIXED\|VTEXTFIXED\|VUNSET, "TERM="},
98	#endif
99	{NULL, 0, NULL}
100	};
101
102	struct var *vartab[VTABSIZE];
103
104	STATIC void unsetvar __P((char *));
105	STATIC struct var *hashvar __P((char ));
106	STATIC int varequal __P((char , char ));
107
108	/*
109	* Initialize the varable symbol tables and import the environment
110	*/
111
112	#ifdef mkinit
113	INCLUDE "var.h"
114	INIT {
115	char **envp;
116	extern char **environ;
117
118	initvar();
119	for (envp = environ ; *envp ; envp++) {
120	if (strchr(*envp, '=')) {
121	setvareq(*envp, VEXPORT\|VTEXTFIXED);
122	}
123	}
124	}
125	#endif
126
127
128	/*
129	* This routine initializes the builtin variables. It is called when the
130	* shell is initialized and again when a shell procedure is spawned.
131	*/
132
133	void
134	initvar() {
135	const struct varinit *ip;
136	struct var *vp;
137	struct var **vpp;
138
139	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
140	if ((vp->flags & VEXPORT) == 0) {
141	vpp = hashvar(ip->text);
142	vp->next = *vpp;
143	*vpp = vp;
144	vp->text = ip->text;
145	vp->flags = ip->flags;
146	}
147	}
148	/*
149	* PS1 depends on uid
150	*/
151	if ((vps1.flags & VEXPORT) == 0) {
152	vpp = hashvar("PS1=");
153	vps1.next = *vpp;
154	*vpp = &vps1;
155	vps1.text = getuid() ? "PS1=$ " : "PS1=# ";
156	vps1.flags = VSTRFIXED\|VTEXTFIXED;
157	}
158	}
159
160	/*
161	* Set the value of a variable. The flags argument is ored with the
162	* flags of the variable. If val is NULL, the variable is unset.
163	*/
164
165	void
166	setvar(name, val, flags)
167	char name, val;
168	{
169	char p, q;
170	int len;
171	int namelen;
172	char *nameeq;
173	int isbad;
174
175	isbad = 0;
176	p = name;
177	if (! is_name(*p++))
178	isbad = 1;
179	for (;;) {
180	if (! is_in_name(*p)) {
181	if (p == '\0' \|\| p == '=')
182	break;
183	isbad = 1;
184	}
185	p++;
186	}
187	namelen = p - name;
188	if (isbad)
189	error("%.*s: is read only", namelen, name);
190	len = namelen + 2; /* 2 is space for '=' and '\0' */
191	if (val == NULL) {
192	flags \|= VUNSET;
193	} else {
194	len += strlen(val);
195	}
196	p = nameeq = ckmalloc(len);
197	q = name;
198	while (--namelen >= 0)
199	p++ = q++;
200	*p++ = '=';
201	*p = '\0';
202	if (val)
203	scopy(val, p);
204	setvareq(nameeq, flags);
205	}
206
207
208
209	/*
210	* Same as setvar except that the variable and value are passed in
211	* the first argument as name=value. Since the first argument will
212	* be actually stored in the table, it should not be a string that
213	* will go away.
214	*/
215
216	void
217	setvareq(s, flags)
218	char *s;
219	{
220	struct var vp, *vpp;
221
222	vpp = hashvar(s);
223	for (vp = *vpp ; vp ; vp = vp->next) {
224	if (varequal(s, vp->text)) {
225	if (vp->flags & VREADONLY) {
226	int len = strchr(s, '=') - s;
227	error("%.*s: is read only", len, s);
228	}
229	INTOFF;
230	if (vp == &vpath)
231	changepath(s + 5); /* 5 = strlen("PATH=") */
232	if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
233	ckfree(vp->text);
234	vp->flags &=~ (VTEXTFIXED\|VSTACK\|VUNSET);
235	vp->flags \|= flags;
236	vp->text = s;
237	if (vp == &vmpath \|\| (vp == &vmail && ! mpathset()))
238	chkmail(1);
239	INTON;
240	return;
241	}
242	}
243	/* not found */
244	vp = ckmalloc(sizeof (*vp));
245	vp->flags = flags;
246	vp->text = s;
247	vp->next = *vpp;
248	*vpp = vp;
249	}
250
251
252
253	/*
254	* Process a linked list of variable assignments.
255	*/
256
257	void
258	listsetvar(list)
259	struct strlist *list;
260	{
261	struct strlist *lp;
262
263	INTOFF;
264	for (lp = list ; lp ; lp = lp->next) {
265	setvareq(savestr(lp->text), 0);
266	}
267	INTON;
268	}
269
270
271
272	/*
273	* Find the value of a variable. Returns NULL if not set.
274	*/
275
276	char *
277	lookupvar(name)
278	char *name;
279	{
280	struct var *v;
281
282	for (v = *hashvar(name) ; v ; v = v->next) {
283	if (varequal(v->text, name)) {
284	if (v->flags & VUNSET)
285	return NULL;
286	return strchr(v->text, '=') + 1;
287	}
288	}
289	return NULL;
290	}
291
292
293
294	/*
295	* Search the environment of a builtin command. If the second argument
296	* is nonzero, return the value of a variable even if it hasn't been
297	* exported.
298	*/
299
300	char *
301	bltinlookup(name, doall)
302	char *name;
303	{
304	struct strlist *sp;
305	struct var *v;
306
307	for (sp = cmdenviron ; sp ; sp = sp->next) {
308	if (varequal(sp->text, name))
309	return strchr(sp->text, '=') + 1;
310	}
311	for (v = *hashvar(name) ; v ; v = v->next) {
312	if (varequal(v->text, name)) {
313	if (v->flags & VUNSET
314	\|\| ! doall && (v->flags & VEXPORT) == 0)
315	return NULL;
316	return strchr(v->text, '=') + 1;
317	}
318	}
319	return NULL;
320	}
321
322
323
324	/*
325	* Generate a list of exported variables. This routine is used to construct
326	* the third argument to execve when executing a program.
327	*/
328
329	char **
330	environment() {
331	int nenv;
332	struct var **vpp;
333	struct var *vp;
334	char env, ep;
335
336	nenv = 0;
337	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
338	for (vp = *vpp ; vp ; vp = vp->next)
339	if (vp->flags & VEXPORT)
340	nenv++;
341	}
342	ep = env = stalloc((nenv + 1) * sizeof *env);
343	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
344	for (vp = *vpp ; vp ; vp = vp->next)
345	if (vp->flags & VEXPORT)
346	*ep++ = vp->text;
347	}
348	*ep = NULL;
349	return env;
350	}
351
352
353	/*
354	* Called when a shell procedure is invoked to clear out nonexported
355	* variables. It is also necessary to reallocate variables of with
356	* VSTACK set since these are currently allocated on the stack.
357	*/
358
359	#ifdef mkinit
360	MKINIT void shprocvar();
361
362	SHELLPROC {
363	shprocvar();
364	}
365	#endif
366
367	void
368	shprocvar() {
369	struct var **vpp;
370	struct var vp, *prev;
371
372	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
373	for (prev = vpp ; (vp = *prev) != NULL ; ) {
374	if ((vp->flags & VEXPORT) == 0) {
375	*prev = vp->next;
376	if ((vp->flags & VTEXTFIXED) == 0)
377	ckfree(vp->text);
378	if ((vp->flags & VSTRFIXED) == 0)
379	ckfree(vp);
380	} else {
381	if (vp->flags & VSTACK) {
382	vp->text = savestr(vp->text);
383	vp->flags &=~ VSTACK;
384	}
385	prev = &vp->next;
386	}
387	}
388	}
389	initvar();
390	}
391
392
393
394	/*
395	* Command to list all variables which are set. Currently this command
396	* is invoked from the set command when the set command is called without
397	* any variables.
398	*/
399
400	int
401	showvarscmd(argc, argv) char **argv; {
402	struct var **vpp;
403	struct var *vp;
404
405	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
406	for (vp = *vpp ; vp ; vp = vp->next) {
407	if ((vp->flags & VUNSET) == 0)
408	out1fmt("%s\n", vp->text);
409	}
410	}
411	return 0;
412	}
413
414
415
416	/*
417	* The export and readonly commands.
418	*/
419
420	int
421	exportcmd(argc, argv) char **argv; {
422	struct var **vpp;
423	struct var *vp;
424	char *name;
425	char *p;
426	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
427
428	listsetvar(cmdenviron);
429	if (argc > 1) {
430	while ((name = *argptr++) != NULL) {
431	if ((p = strchr(name, '=')) != NULL) {
432	p++;
433	} else {
434	vpp = hashvar(name);
435	for (vp = *vpp ; vp ; vp = vp->next) {
436	if (varequal(vp->text, name)) {
437	vp->flags \|= flag;
438	goto found;
439	}
440	}
441	}
442	setvar(name, p, flag);
443	found:;
444	}
445	} else {
446	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
447	for (vp = *vpp ; vp ; vp = vp->next) {
448	if (vp->flags & flag) {
449	for (p = vp->text ; *p != '=' ; p++)
450	out1c(*p);
451	out1c('\n');
452	}
453	}
454	}
455	}
456	return 0;
457	}
458
459
460	/*
461	* The "local" command.
462	*/
463
464	localcmd(argc, argv) char **argv; {
465	char *name;
466
467	if (! in_function())
468	error("Not in a function");
469	while ((name = *argptr++) != NULL) {
470	mklocal(name);
471	}
472	return 0;
473	}
474
475
476	/*
477	* Make a variable a local variable. When a variable is made local, it's
478	* value and flags are saved in a localvar structure. The saved values
479	* will be restored when the shell function returns. We handle the name
480	* "-" as a special case.
481	*/
482
483	void
484	mklocal(name)
485	char *name;
486	{
487	struct localvar *lvp;
488	struct var **vpp;
489	struct var *vp;
490
491	INTOFF;
492	lvp = ckmalloc(sizeof (struct localvar));
493	if (name[0] == '-' && name[1] == '\0') {
494	lvp->text = ckmalloc(sizeof optval);
495	bcopy(optval, lvp->text, sizeof optval);
496	vp = NULL;
497	} else {
498	vpp = hashvar(name);
499	for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
500	if (vp == NULL) {
501	if (strchr(name, '='))
502	setvareq(savestr(name), VSTRFIXED);
503	else
504	setvar(name, NULL, VSTRFIXED);
505	vp = vpp; / the new variable */
506	lvp->text = NULL;
507	lvp->flags = VUNSET;
508	} else {
509	lvp->text = vp->text;
510	lvp->flags = vp->flags;
511	vp->flags \|= VSTRFIXED\|VTEXTFIXED;
512	if (strchr(name, '='))
513	setvareq(savestr(name), 0);
514	}
515	}
516	lvp->vp = vp;
517	lvp->next = localvars;
518	localvars = lvp;
519	INTON;
520	}
521
522
523	/*
524	* Called after a function returns.
525	*/
526
527	void
528	poplocalvars() {
529	struct localvar *lvp;
530	struct var *vp;
531
532	while ((lvp = localvars) != NULL) {
533	localvars = lvp->next;
534	vp = lvp->vp;
535	if (vp == NULL) { /* $- saved */
536	bcopy(lvp->text, optval, sizeof optval);
537	ckfree(lvp->text);
538	} else if ((lvp->flags & (VUNSET\|VSTRFIXED)) == VUNSET) {
539	unsetvar(vp->text);
540	} else {
541	if ((vp->flags & VTEXTFIXED) == 0)
542	ckfree(vp->text);
543	vp->flags = lvp->flags;
544	vp->text = lvp->text;
545	}
546	ckfree(lvp);
547	}
548	}
549
550
551	setvarcmd(argc, argv) char **argv; {
552	if (argc <= 2)
553	return unsetcmd(argc, argv);
554	else if (argc == 3)
555	setvar(argv[1], argv[2], 0);
556	else
557	error("List assignment not implemented");
558	return 0;
559	}
560
561
562	/*
563	* The unset builtin command. We unset the function before we unset the
564	* variable to allow a function to be unset when there is a readonly variable
565	* with the same name.
566	*/
567
568	unsetcmd(argc, argv) char **argv; {
569	char **ap;
570
571	for (ap = argv + 1 ; *ap ; ap++) {
572	unsetfunc(*ap);
573	unsetvar(*ap);
574	}
575	return 0;
576	}
577
578
579	/*
580	* Unset the specified variable.
581	*/
582
583	STATIC void
584	unsetvar(s)
585	char *s;
586	{
587	struct var **vpp;
588	struct var *vp;
589
590	vpp = hashvar(s);
591	for (vp = vpp ; vp ; vpp = &vp->next, vp = vpp) {
592	if (varequal(vp->text, s)) {
593	INTOFF;
594	if (*(strchr(vp->text, '=') + 1) != '\0'
595	\|\| vp->flags & VREADONLY) {
596	setvar(s, nullstr, 0);
597	}
598	vp->flags &=~ VEXPORT;
599	vp->flags \|= VUNSET;
600	if ((vp->flags & VSTRFIXED) == 0) {
601	if ((vp->flags & VTEXTFIXED) == 0)
602	ckfree(vp->text);
603	*vpp = vp->next;
604	ckfree(vp);
605	}
606	INTON;
607	return;
608	}
609	}
610	}
611
612
613
614	/*
615	* Find the appropriate entry in the hash table from the name.
616	*/
617
618	STATIC struct var **
619	hashvar(p)
620	register char *p;
621	{
622	unsigned int hashval;
623
624	hashval = *p << 4;
625	while (p && p != '=')
626	hashval += *p++;
627	return &vartab[hashval % VTABSIZE];
628	}
629
630
631
632	/*
633	* Returns true if the two strings specify the same varable. The first
634	* variable name is terminated by '='; the second may be terminated by
635	* either '=' or '\0'.
636	*/
637
638	STATIC int
639	varequal(p, q)
640	register char p, q;
641	{
642	while (p == q++) {
643	if (*p++ == '=')
644	return 1;
645	}
646	if (p == '=' && (q - 1) == '\0')
647	return 1;
648	return 0;
649	}