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

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)var.c	8.1 (Berkeley) %G%";
#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 vhistsize;
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
	{&vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE="},
	{&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 int 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 = geteuid() ? "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: bad variable name", 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);
			if (vp == &vhistsize)
				sethistsize();
			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 optlist);
		bcopy(optlist, lvp->text, sizeof optlist);
		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, optlist, sizeof optlist);
			ckfree(lvp->text);
		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
			(void)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;
	int i;
	int flg_func = 0;
	int flg_var = 0;
	int ret = 0;

	while ((i = nextopt("vf")) != '\0') {
		if (i == 'f')
			flg_func = 1;
		else
			flg_var = 1;
	}
	if (flg_func == 0 && flg_var == 0)
		flg_var = 1;
			
	for (ap = argptr; *ap ; ap++) {
		if (flg_func)
			ret |= unsetfunc(*ap);
		if (flg_var)
			ret |= unsetvar(*ap);
	}
	return ret;
}


/*
 * Unset the specified variable.
 */

STATIC int
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)) {
			if (vp->flags & VREADONLY)
				return (1);
			INTOFF;
			if (*(strchr(vp->text, '=') + 1) != '\0')
				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 (0);
		}
	}

	return (1);
}


/*
 * 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
8f1981e0	1	/*-
d1b73048 KB	2	* Copyright (c) 1991, 1993
d1b73048 KB	3	* The Regents of the University of California. All rights reserved.
8f1981e0 KB	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Kenneth Almquist.
	7	*
	8	* %sccs.include.redist.c%
	9	*/
	10
	11	#ifndef lint
d1b73048	12	static char sccsid[] = "@(#)var.c 8.1 (Berkeley) %G%";
8f1981e0 KB	13	#endif /* not lint */
	14
	15	/*
	16	* Shell variables.
	17	*/
	18
8f1981e0 KB	19	#include "shell.h"
	20	#include "output.h"
	21	#include "expand.h"
	22	#include "nodes.h" /* for other headers */
	23	#include "eval.h" /* defines cmdenviron */
	24	#include "exec.h"
	25	#include "syntax.h"
	26	#include "options.h"
	27	#include "mail.h"
	28	#include "var.h"
	29	#include "memalloc.h"
	30	#include "error.h"
	31	#include "mystring.h"
	32
	33
	34	#define VTABSIZE 39
	35
	36
	37	struct varinit {
	38	struct var *var;
	39	int flags;
	40	char *text;
	41	};
	42
	43
	44	#if ATTY
	45	struct var vatty;
	46	#endif
1da339d9	47	struct var vhistsize;
8f1981e0 KB	48	struct var vifs;
	49	struct var vmail;
	50	struct var vmpath;
	51	struct var vpath;
	52	struct var vps1;
	53	struct var vps2;
	54	struct var vvers;
	55	#if ATTY
	56	struct var vterm;
	57	#endif
	58
	59	const struct varinit varinit[] = {
	60	#if ATTY
	61	{&vatty, VSTRFIXED\|VTEXTFIXED\|VUNSET, "ATTY="},
	62	#endif
1da339d9	63	{&vhistsize, VSTRFIXED\|VTEXTFIXED\|VUNSET, "HISTSIZE="},
8f1981e0 KB	64	{&vifs, VSTRFIXED\|VTEXTFIXED, "IFS= \t\n"},
	65	{&vmail, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAIL="},
	66	{&vmpath, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAILPATH="},
	67	{&vpath, VSTRFIXED\|VTEXTFIXED, "PATH=:/bin:/usr/bin"},
913003f6 MT	68	/*
	69	* vps1 depends on uid
	70	*/
8f1981e0	71	{&vps2, VSTRFIXED\|VTEXTFIXED, "PS2=> "},
8f1981e0 KB	72	#if ATTY
	73	{&vterm, VSTRFIXED\|VTEXTFIXED\|VUNSET, "TERM="},
	74	#endif
	75	{NULL, 0, NULL}
	76	};
	77
	78	struct var *vartab[VTABSIZE];
	79
e6fa84d4	80	STATIC int unsetvar __P((char *));
913003f6 MT	81	STATIC struct var *hashvar __P((char ));
913003f6 MT	82	STATIC int varequal __P((char , char ));
8f1981e0 KB	83
	84	/*
	85	* Initialize the varable symbol tables and import the environment
	86	*/
	87
	88	#ifdef mkinit
	89	INCLUDE "var.h"
	90	INIT {
	91	char **envp;
	92	extern char **environ;
	93
	94	initvar();
	95	for (envp = environ ; *envp ; envp++) {
	96	if (strchr(*envp, '=')) {
	97	setvareq(*envp, VEXPORT\|VTEXTFIXED);
	98	}
	99	}
	100	}
	101	#endif
	102
	103
	104	/*
	105	* This routine initializes the builtin variables. It is called when the
	106	* shell is initialized and again when a shell procedure is spawned.
	107	*/
	108
	109	void
	110	initvar() {
	111	const struct varinit *ip;
	112	struct var *vp;
	113	struct var **vpp;
	114
	115	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
	116	if ((vp->flags & VEXPORT) == 0) {
	117	vpp = hashvar(ip->text);
	118	vp->next = *vpp;
	119	*vpp = vp;
	120	vp->text = ip->text;
	121	vp->flags = ip->flags;
	122	}
	123	}
913003f6 MT	124	/*
	125	* PS1 depends on uid
	126	*/
	127	if ((vps1.flags & VEXPORT) == 0) {
	128	vpp = hashvar("PS1=");
	129	vps1.next = *vpp;
	130	*vpp = &vps1;
d08083e8	131	vps1.text = geteuid() ? "PS1=$ " : "PS1=# ";
913003f6 MT	132	vps1.flags = VSTRFIXED\|VTEXTFIXED;
913003f6 MT	133	}
ddba57cd	134	}
8f1981e0 KB	135
	136	/*
	137	* Set the value of a variable. The flags argument is ored with the
	138	* flags of the variable. If val is NULL, the variable is unset.
	139	*/
	140
	141	void
	142	setvar(name, val, flags)
	143	char name, val;
	144	{
	145	char p, q;
	146	int len;
	147	int namelen;
	148	char *nameeq;
	149	int isbad;
	150
	151	isbad = 0;
	152	p = name;
	153	if (! is_name(*p++))
	154	isbad = 1;
	155	for (;;) {
	156	if (! is_in_name(*p)) {
	157	if (p == '\0' \|\| p == '=')
	158	break;
	159	isbad = 1;
	160	}
	161	p++;
	162	}
	163	namelen = p - name;
	164	if (isbad)
c671e886	165	error("%.*s: bad variable name", namelen, name);
8f1981e0 KB	166	len = namelen + 2; /* 2 is space for '=' and '\0' */
	167	if (val == NULL) {
	168	flags \|= VUNSET;
	169	} else {
	170	len += strlen(val);
	171	}
	172	p = nameeq = ckmalloc(len);
	173	q = name;
	174	while (--namelen >= 0)
	175	p++ = q++;
	176	*p++ = '=';
	177	*p = '\0';
	178	if (val)
	179	scopy(val, p);
	180	setvareq(nameeq, flags);
	181	}
	182
	183
	184
	185	/*
	186	* Same as setvar except that the variable and value are passed in
	187	* the first argument as name=value. Since the first argument will
	188	* be actually stored in the table, it should not be a string that
	189	* will go away.
	190	*/
	191
	192	void
	193	setvareq(s, flags)
	194	char *s;
	195	{
	196	struct var vp, *vpp;
	197
	198	vpp = hashvar(s);
	199	for (vp = *vpp ; vp ; vp = vp->next) {
	200	if (varequal(s, vp->text)) {
	201	if (vp->flags & VREADONLY) {
	202	int len = strchr(s, '=') - s;
	203	error("%.*s: is read only", len, s);
	204	}
	205	INTOFF;
	206	if (vp == &vpath)
	207	changepath(s + 5); /* 5 = strlen("PATH=") */
	208	if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
	209	ckfree(vp->text);
	210	vp->flags &=~ (VTEXTFIXED\|VSTACK\|VUNSET);
	211	vp->flags \|= flags;
	212	vp->text = s;
	213	if (vp == &vmpath \|\| (vp == &vmail && ! mpathset()))
	214	chkmail(1);
1da339d9 MT	215	if (vp == &vhistsize)
1da339d9 MT	216	sethistsize();
8f1981e0 KB	217	INTON;
	218	return;
	219	}
	220	}
	221	/* not found */
	222	vp = ckmalloc(sizeof (*vp));
	223	vp->flags = flags;
	224	vp->text = s;
	225	vp->next = *vpp;
	226	*vpp = vp;
	227	}
	228
	229
	230
	231	/*
	232	* Process a linked list of variable assignments.
	233	*/
	234
	235	void
	236	listsetvar(list)
	237	struct strlist *list;
	238	{
	239	struct strlist *lp;
	240
	241	INTOFF;
	242	for (lp = list ; lp ; lp = lp->next) {
	243	setvareq(savestr(lp->text), 0);
	244	}
	245	INTON;
	246	}
	247
	248
	249
	250	/*
	251	* Find the value of a variable. Returns NULL if not set.
	252	*/
	253
	254	char *
	255	lookupvar(name)
	256	char *name;
	257	{
	258	struct var *v;
	259
	260	for (v = *hashvar(name) ; v ; v = v->next) {
	261	if (varequal(v->text, name)) {
	262	if (v->flags & VUNSET)
	263	return NULL;
	264	return strchr(v->text, '=') + 1;
	265	}
	266	}
	267	return NULL;
	268	}
	269
	270
	271
	272	/*
	273	* Search the environment of a builtin command. If the second argument
	274	* is nonzero, return the value of a variable even if it hasn't been
	275	* exported.
	276	*/
	277
	278	char *
	279	bltinlookup(name, doall)
	280	char *name;
281	{
282	struct strlist *sp;
283	struct var *v;
284
285	for (sp = cmdenviron ; sp ; sp = sp->next) {
286	if (varequal(sp->text, name))
287	return strchr(sp->text, '=') + 1;
288	}
289	for (v = *hashvar(name) ; v ; v = v->next) {
290	if (varequal(v->text, name)) {
291	if (v->flags & VUNSET
292	\|\| ! doall && (v->flags & VEXPORT) == 0)
293	return NULL;
294	return strchr(v->text, '=') + 1;
295	}
296	}
297	return NULL;
298	}
299
300
301
302	/*
303	* Generate a list of exported variables. This routine is used to construct
304	* the third argument to execve when executing a program.
305	*/
306
307	char **
308	environment() {
309	int nenv;
310	struct var **vpp;
311	struct var *vp;
312	char env, ep;
313
314	nenv = 0;
315	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
316	for (vp = *vpp ; vp ; vp = vp->next)
317	if (vp->flags & VEXPORT)
318	nenv++;
319	}
320	ep = env = stalloc((nenv + 1) * sizeof *env);
321	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
322	for (vp = *vpp ; vp ; vp = vp->next)
323	if (vp->flags & VEXPORT)
324	*ep++ = vp->text;
325	}
326	*ep = NULL;
327	return env;
328	}
329
330
331	/*
332	* Called when a shell procedure is invoked to clear out nonexported
333	* variables. It is also necessary to reallocate variables of with
334	* VSTACK set since these are currently allocated on the stack.
335	*/
336
337	#ifdef mkinit
338	MKINIT void shprocvar();
339
340	SHELLPROC {
341	shprocvar();
342	}
343	#endif
344
345	void
346	shprocvar() {
347	struct var **vpp;
348	struct var vp, *prev;
349
350	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
351	for (prev = vpp ; (vp = *prev) != NULL ; ) {
352	if ((vp->flags & VEXPORT) == 0) {
353	*prev = vp->next;
354	if ((vp->flags & VTEXTFIXED) == 0)
355	ckfree(vp->text);
356	if ((vp->flags & VSTRFIXED) == 0)
357	ckfree(vp);
358	} else {
359	if (vp->flags & VSTACK) {
360	vp->text = savestr(vp->text);
361	vp->flags &=~ VSTACK;
362	}
363	prev = &vp->next;
364	}
365	}
366	}
367	initvar();
368	}
369
370
371
372	/*
373	* Command to list all variables which are set. Currently this command
374	* is invoked from the set command when the set command is called without
375	* any variables.
376	*/
377
378	int
379	showvarscmd(argc, argv) char **argv; {
380	struct var **vpp;
381	struct var *vp;
382
383	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
384	for (vp = *vpp ; vp ; vp = vp->next) {
385	if ((vp->flags & VUNSET) == 0)
386	out1fmt("%s\n", vp->text);
387	}
388	}
389	return 0;
390	}
391
392
393
394	/*
395	* The export and readonly commands.
396	*/
397
398	int
399	exportcmd(argc, argv) char **argv; {
400	struct var **vpp;
401	struct var *vp;
402	char *name;
403	char *p;
404	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
405
406	listsetvar(cmdenviron);
407	if (argc > 1) {
408	while ((name = *argptr++) != NULL) {
409	if ((p = strchr(name, '=')) != NULL) {
410	p++;
411	} else {
412	vpp = hashvar(name);
413	for (vp = *vpp ; vp ; vp = vp->next) {
414	if (varequal(vp->text, name)) {
415	vp->flags \|= flag;
416	goto found;
417	}
418	}
419	}
420	setvar(name, p, flag);
421	found:;
422	}
423	} else {
424	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
425	for (vp = *vpp ; vp ; vp = vp->next) {
426	if (vp->flags & flag) {
427	for (p = vp->text ; *p != '=' ; p++)
428	out1c(*p);
429	out1c('\n');
430	}
431	}
432	}
433	}
434	return 0;
435	}
436
437
438	/*
439	* The "local" command.
440	*/
441
442	localcmd(argc, argv) char **argv; {
443	char *name;
444
445	if (! in_function())
446	error("Not in a function");
447	while ((name = *argptr++) != NULL) {
448	mklocal(name);
449	}
450	return 0;
451	}
452
453
454	/*
455	* Make a variable a local variable. When a variable is made local, it's
456	* value and flags are saved in a localvar structure. The saved values
457	* will be restored when the shell function returns. We handle the name
458	* "-" as a special case.
459	*/
460
461	void
462	mklocal(name)
463	char *name;
464	{
465	struct localvar *lvp;
466	struct var **vpp;
467	struct var *vp;
468
469	INTOFF;
470	lvp = ckmalloc(sizeof (struct localvar));
471	if (name[0] == '-' && name[1] == '\0') {
1da339d9 MT	472	lvp->text = ckmalloc(sizeof optlist);
1da339d9 MT	473	bcopy(optlist, lvp->text, sizeof optlist);
8f1981e0 KB	474	vp = NULL;
	475	} else {
	476	vpp = hashvar(name);
	477	for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
	478	if (vp == NULL) {
	479	if (strchr(name, '='))
	480	setvareq(savestr(name), VSTRFIXED);
	481	else
	482	setvar(name, NULL, VSTRFIXED);
	483	vp = vpp; / the new variable */
	484	lvp->text = NULL;
	485	lvp->flags = VUNSET;
	486	} else {
	487	lvp->text = vp->text;
	488	lvp->flags = vp->flags;
	489	vp->flags \|= VSTRFIXED\|VTEXTFIXED;
	490	if (strchr(name, '='))
	491	setvareq(savestr(name), 0);
	492	}
	493	}
	494	lvp->vp = vp;
	495	lvp->next = localvars;
	496	localvars = lvp;
	497	INTON;
	498	}
	499
	500
	501	/*
	502	* Called after a function returns.
	503	*/
	504
	505	void
	506	poplocalvars() {
	507	struct localvar *lvp;
	508	struct var *vp;
	509
	510	while ((lvp = localvars) != NULL) {
	511	localvars = lvp->next;
	512	vp = lvp->vp;
	513	if (vp == NULL) { /* $- saved */
1da339d9	514	bcopy(lvp->text, optlist, sizeof optlist);
8f1981e0 KB	515	ckfree(lvp->text);
8f1981e0 KB	516	} else if ((lvp->flags & (VUNSET\|VSTRFIXED)) == VUNSET) {
e6fa84d4	517	(void)unsetvar(vp->text);
8f1981e0 KB	518	} else {
	519	if ((vp->flags & VTEXTFIXED) == 0)
	520	ckfree(vp->text);
	521	vp->flags = lvp->flags;
	522	vp->text = lvp->text;
	523	}
	524	ckfree(lvp);
	525	}
	526	}
	527
	528
	529	setvarcmd(argc, argv) char **argv; {
	530	if (argc <= 2)
	531	return unsetcmd(argc, argv);
	532	else if (argc == 3)
	533	setvar(argv[1], argv[2], 0);
	534	else
	535	error("List assignment not implemented");
	536	return 0;
	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	unsetcmd(argc, argv) char **argv; {
	547	char **ap;
e6fa84d4 MT	548	int i;
	549	int flg_func = 0;
	550	int flg_var = 0;
	551	int ret = 0;
	552
	553	while ((i = nextopt("vf")) != '\0') {
	554	if (i == 'f')
	555	flg_func = 1;
	556	else
	557	flg_var = 1;
8f1981e0	558	}
e6fa84d4 MT	559	if (flg_func == 0 && flg_var == 0)
	560	flg_var = 1;
	561
	562	for (ap = argptr; *ap ; ap++) {
	563	if (flg_func)
	564	ret \|= unsetfunc(*ap);
	565	if (flg_var)
	566	ret \|= unsetvar(*ap);
	567	}
	568	return ret;
8f1981e0 KB	569	}
	570
	571
	572	/*
	573	* Unset the specified variable.
	574	*/
	575
e6fa84d4	576	STATIC int
8f1981e0 KB	577	unsetvar(s)
	578	char *s;
	579	{
	580	struct var **vpp;
	581	struct var *vp;
	582
	583	vpp = hashvar(s);
	584	for (vp = vpp ; vp ; vpp = &vp->next, vp = vpp) {
	585	if (varequal(vp->text, s)) {
e6fa84d4 MT	586	if (vp->flags & VREADONLY)
e6fa84d4 MT	587	return (1);
8f1981e0	588	INTOFF;
e6fa84d4	589	if (*(strchr(vp->text, '=') + 1) != '\0')
8f1981e0	590	setvar(s, nullstr, 0);
8f1981e0 KB	591	vp->flags &=~ VEXPORT;
	592	vp->flags \|= VUNSET;
	593	if ((vp->flags & VSTRFIXED) == 0) {
	594	if ((vp->flags & VTEXTFIXED) == 0)
	595	ckfree(vp->text);
	596	*vpp = vp->next;
	597	ckfree(vp);
	598	}
	599	INTON;
e6fa84d4	600	return (0);
8f1981e0 KB	601	}
8f1981e0 KB	602	}
e6fa84d4 MT	603
e6fa84d4 MT	604	return (1);
8f1981e0 KB	605	}
	606
	607
	608
	609	/*
	610	* Find the appropriate entry in the hash table from the name.
	611	*/
	612
	613	STATIC struct var **
	614	hashvar(p)
	615	register char *p;
	616	{
	617	unsigned int hashval;
	618
	619	hashval = *p << 4;
	620	while (p && p != '=')
	621	hashval += *p++;
	622	return &vartab[hashval % VTABSIZE];
	623	}
	624
	625
	626
	627	/*
	628	* Returns true if the two strings specify the same varable. The first
	629	* variable name is terminated by '='; the second may be terminated by
	630	* either '=' or '\0'.
	631	*/
	632
	633	STATIC int
	634	varequal(p, q)
	635	register char p, q;
	636	{
	637	while (p == q++) {
	638	if (*p++ == '=')
	639	return 1;
	640	}
	641	if (p == '=' && (q - 1) == '\0')
	642	return 1;
	643	return 0;
	644	}