libc: introduce <envvars.h>

The new header envvars.h contains the names of commonly used
environment variables, such as $user, $ifs, $path and so on.

These defines are useful for Jehanne core applications that
use them to comunicate some values.

They are not strictly required, but having such defines we
can easily change the naming convention (from lowercase to uppercase).

sys/include/envvars.h

@@ -0,0 +1,44 @@
+/*
+ * This file is part of Jehanne.
+ *
+ * Copyright (C) 2017 Giacomo Tesio <giacomo@tesio.it>
+ *
+ * Jehanne is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * Jehanne is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Jehanne.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* This file defines the names of a few environment variables shared
+ * among the userspace tools provided by Jehanne.
+ *
+ * It must not provide defines for variables used by commonly installed
+ * softwares, just the one used by the core tools, the one required
+ * to boot a minimal system.
+ */
+
+#define ENV_APID	"apid"
+#define ENV_USER	"user"
+#define ENV_HOME	"home"
+#define ENV_IFS		"ifs"
+#define ENV_PATH	"path"
+#define ENV_PID		"pid"
+#define ENV_PROMPT	"prompt"
+#define ENV_STATUS	"status"
+#define ENV_CDPATH	"cdpath"
+#define ENV_CPUTYPE	"cputype"
+#define ENV_SERVICE	"service"
+#define ENV_SYSNAME	"sysname"
+#define ENV_OBJTYPE	"objtype"
+
+#define ENV_WSYS	"wsys"
+
+extern	char*	jehanne_getenv(const char*);
+extern	int	jehanne_putenv(const char*, const char*);

sys/include/libc.h

@@ -325,7 +325,6 @@ extern	int	jehanne_encodefmt(Fmt*);
 extern	void	jehanne_exits(const char*) __attribute__ ((noreturn));
 extern	double	jehanne_frexp(double, int*);
 extern	uintptr_t	jehanne_getcallerpc(void);
-extern	char*	jehanne_getenv(const char*);
 extern	int	jehanne_getfields(char*, char**, int, int, const char*);
 extern	int	jehanne_gettokens(char *, char **, int, const char *);
 extern	char*	jehanne_getuser(void);
@@ -344,7 +343,6 @@ extern	void	jehanne_perror(const char*);
 extern	int	jehanne_pipe(int pipes[2]);
 extern	int	jehanne_postnote(int, int, const char *);
 extern	double	jehanne_pow10(int);
-extern	int	jehanne_putenv(const char*, const char*);
 extern	void	jehanne_qsort(void*, long, int,
 			int (*)(const void*, const void*));
 extern	void*	jehanne_bsearch(const void* key, const void* base, size_t nmemb, size_t size,

sys/src/cmd/acme/acme.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <draw.h>
 #include <thread.h>
 #include <cursor.h>
@@ -124,9 +125,9 @@ threadmain(int argc, char *argv[])
 	fontnames[1] = estrdup(fontnames[1]);
 
 	quotefmtinstall();
-	cputype = getenv("cputype");
+	cputype = getenv(ENV_CPUTYPE);
-	objtype = getenv("objtype");
+	objtype = getenv(ENV_OBJTYPE);
-	home = getenv("home");
+	home = getenv(ENV_HOME);
 	p = getenv("tabstop");
 	if(p != nil){
 		maxtab = strtoul(p, nil, 0);

sys/src/cmd/acme/aux/win/main.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <thread.h>
 #include <9P2000.h>
@@ -61,7 +62,7 @@ threadmain(int argc, char *argv[])
 		av = emalloc(3*sizeof(char*));
 		av[0] = "rc";
 		av[1] = "-i";
-		name = getenv("sysname");
+		name = getenv(ENV_SYSNAME);
 	}else{
 		av = argv;
 		name = utfrrune(av[0], '/');

sys/src/cmd/acme/exec.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <draw.h>
 #include <thread.h>
 #include <cursor.h>

sys/src/cmd/auth/as.c

@@ -63,7 +63,7 @@ runas(char *user, char *cmd)
 {
 	if(becomeuser(user) < 0)
 		sysfatal("can't change uid for %s: %r", user);
-	putenv("service", "rx");
+	putenv(ENV_SERVICE, "rx");
 	execl("/bin/rc", "rc", "-lc", cmd, nil);
 	sysfatal("exec /bin/rc: %r");
 }

sys/src/cmd/auth/cron.c

@@ -568,7 +568,7 @@ rexec(User *user, Job *j)
 	open("/dev/null", OWRITE);
 
 	if(strcmp(j->host, "local") == 0){
-		putenv("service", "rx");
+		putenv(ENV_SERVICE, "rx");
 		execl("/bin/rc", "rc", "-lc", buf, nil);
 	} else {
 		execl("/bin/rx", "rx", j->host, buf, nil);

sys/src/cmd/auth/factotum/util.c

@@ -1,3 +1,4 @@
+#include <envvars.h>
 #include "dat.h"
 
 //static char secstore[100];   /* server name */ // NOT USED
@@ -712,7 +713,7 @@ promptforhostowner(void)
 	char owner[64], *p;
 
 	/* hack for bitsy; can't prompt during boot */
-	if(p = getenv("user")){
+	if(p = getenv(ENV_USER)){
 		writehostowner(p);
 		free(p);
 		return;

sys/src/cmd/auth/login.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 #include <authsrv.h>
 #include <bio.h>
@@ -70,10 +71,12 @@ void
 setenv(char *var, char *val)
 {
 	int fd;
+	char buf[128+4];
 
-	fd = ocreate(var, OWRITE, 0644);
+	snprint(buf, sizeof(buf), "#e/%s", var);
+	fd = ocreate(buf, OWRITE, 0644);
 	if(fd < 0)
-		print("init: can't open %s\n", var);
+		print("init: can't open %s\n", buf);
 	else{
 		fprint(fd, val);
 		close(fd);
@@ -126,7 +129,7 @@ getauthdom(void)
 	if(authdom != nil)
 		return authdom;
 
-	sysname = getenv("sysname");
+	sysname = getenv(ENV_SYSNAME);
 	if(sysname == nil)
 		return strdup("cs.bell-labs.com");
 
@@ -209,7 +212,7 @@ main(int argc, char *argv[])
 
 	rfork(RFENVG|RFNAMEG);
 
-	service = getenv("service");
+	service = getenv(ENV_SERVICE);
 	if(strcmp(service, "cpu") == 0)
 		fprint(2, "login: warning: running on a cpu server!\n");
 	if(argc != 1){
@@ -239,24 +242,23 @@ main(int argc, char *argv[])
 	mountfactotum(srvname);
 
 	/* set up a new environment */
-	cputype = getenv("cputype");
+	cputype = getenv(ENV_CPUTYPE);
-	sysname = getenv("sysname");
+	sysname = getenv(ENV_SYSNAME);
 	tz = getenv("timezone");
 	rfork(RFCENVG);
-	setenv("#e/service", "con");
+	setenv(ENV_SERVICE, "con");
-	setenv("#e/user", user);
+	setenv(ENV_USER, user);
 	snprint(home, sizeof(home), "/usr/%s", user);
-	setenv("#e/home", home);
+	setenv(ENV_HOME, home);
-	setenv("#e/cputype", cputype);
+	setenv(ENV_CPUTYPE, cputype);
-	setenv("#e/objtype", cputype);
+	setenv(ENV_OBJTYPE, cputype);
 	if(sysname != nil)
-		setenv("#e/sysname", sysname);
+		setenv(ENV_SYSNAME, sysname);
 	if(tz != nil)
-		setenv("#e/timezone", tz);
+		setenv("timezone", tz);
 
 	/* go to new home directory */
-	snprint(buf, sizeof(buf), "/usr/%s", user);
+	if(chdir(home) < 0)
-	if(chdir(buf) < 0)
 		chdir("/");
 
 	/* read profile and start interactive rc */

sys/src/cmd/auth/netkey.c

@@ -26,7 +26,7 @@ main(int argc, char *argv[])
 	if(argc)
 		usage();
 
-	s = getenv("service");
+	s = getenv(ENV_SERVICE);
 	if(s && strcmp(s, "cpu") == 0){
 		fprint(2, "netkey must not be run on the cpu server\n");
 		exits("boofhead");

sys/src/cmd/auth/secstore/secchk.c

@@ -25,7 +25,7 @@ main(int argc, char **argv)
 		syslog(0, "secstore", "no /lib/ndb/local");
 	db = ndbcat(db, db2);
 
-	print("user=%s\n", getenv("user"));
+	print("%s=%s\n", ENV_USER, getenv(ENV_USER));
-	print("%s\n", secureidcheck(getenv("user"), argv[1]));
+	print("%s\n", secureidcheck(getenv(ENV_USER), argv[1]));
 	exits(0);
 }

sys/src/cmd/awk/tran.c

@@ -24,6 +24,7 @@ THIS SOFTWARE.
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <ctype.h>
 #include <bio.h>
 #include "awk.h"

sys/src/cmd/cpu.c

@@ -16,6 +16,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <auth.h>
 #include <9P2000.h>
@@ -301,7 +302,7 @@ remoteside(int old)
 	int i, n, fd, badchdir, gotcmd;
 
 	rfork(RFENVG);
-	putenv("service", "cpu");
+	putenv(ENV_SERVICE, "cpu");
 	fd = 0;
 
 	/* negotiate authentication mechanism */
@@ -319,9 +320,9 @@ remoteside(int old)
 		fatal(1, "srvauth");
 
 	/* Set environment values for the user */
-	putenv("user", user);
+	putenv(ENV_USER, user);
 	sprint(home, "/usr/%s", user);
-	putenv("home", home);
+	putenv(ENV_HOME, home);
 
 	/* Now collect invoking cpu's current directory or possibly a command */
 	gotcmd = 0;

sys/src/cmd/disk/mkfs.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <disk.h>
 #include <auth.h>
 #include <bio.h>
@@ -115,7 +116,7 @@ main(int argc, char **argv)
 	zbuf = malloc(buflen);
 	memset(zbuf, 0, buflen);
 
-	cputype = getenv("cputype");
+	cputype = getenv(ENV_CPUTYPE);
 	if(cputype == 0)
 		cputype = "386";
 

sys/src/cmd/exportfs/exportfs.c

@@ -12,6 +12,7 @@
  */
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 #include <9P2000.h>
 #include <libsec.h>
@@ -213,7 +214,7 @@ main(int argc, char **argv)
 			fatal("exportfs by none disallowed");
 		if(auth_chuid(ai, nsfile) < 0)
 			fatal("auth_chuid: %r");
-		putenv("service", "exportfs");
+		putenv(ENV_SERVICE, "exportfs");
 	}
 
 	if(srvfdfile){

sys/src/cmd/hget.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <ctype.h>
 #include <bio.h>
 #include <ip.h>

sys/src/cmd/hmi/vga/main.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 
 #include "pci.h"

sys/src/cmd/import.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 #include <libsec.h>
 
@@ -363,7 +364,7 @@ passive(void)
 		sysfatal("auth_proxy: %r");
 	if(auth_chuid(ai, nil) < 0)
 		sysfatal("auth_chuid: %r");
-	putenv("service", "import");
+	putenv(ENV_SERVICE, "import");
 
 	fd = dup(0, -1);
 	close(0);

sys/src/cmd/ip/dhcpclient.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <ip.h>
 #include "dhcp.h"
 
@@ -210,6 +211,7 @@ void
 dhcpinit(void)
 {
 	int fd;
+	char *sysname;
 
 	dhcp.state = Sinit;
 	dhcp.timeout = 4;
@@ -222,7 +224,9 @@ dhcpinit(void)
 		dhcp.xid = time(0)*getpid();
 	srand(dhcp.xid);
 
-	sprint(dhcp.cid, "%s.%d", getenv("sysname"), getpid());
+	sysname = getenv(ENV_SYSNAME);
+	sprint(dhcp.cid, "%s.%d", sysname, getpid());
+	free(sysname);
 }
 
 void

sys/src/cmd/ip/dhcpd/dhcpd.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <ip.h>
 #include <bio.h>
 #include <ndb.h>
@@ -1360,7 +1361,7 @@ readsysname(void)
 			return name;
 		}
 	}
-	p = getenv("sysname");
+	p = getenv(ENV_SYSNAME);
 	if(p == nil || *p == 0)
 		return "unknown";
 	return p;

sys/src/cmd/ip/ipconfig/main.c

@@ -3,6 +3,7 @@
  */
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <ip.h>
 #include <bio.h>
 #include <ndb.h>
@@ -390,7 +391,7 @@ init(void)
  	nsec();			/* make sure time file is open before forking */
 
 	setnetmtpt(conf.mpoint, sizeof conf.mpoint, nil);
-	conf.cputype = getenv("cputype");
+	conf.cputype = getenv(ENV_CPUTYPE);
 	if(conf.cputype == nil)
 		conf.cputype = "386";
 
@@ -410,7 +411,7 @@ parseargs(int argc, char **argv)
 
 	/* default to any host name we already have */
 	if(*conf.hostname == 0){
-		p = getenv("sysname");
+		p = getenv(ENV_SYSNAME);
 		if(p == nil || *p == 0)
 			p = sysname();
 		if(p != nil)

sys/src/cmd/ip/listen.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 
 #define	NAMELEN	64	/* reasonable upper limit for name elements */
@@ -97,7 +98,7 @@ main(int argc, char *argv[])
 	quiet = 0;
 	immutable = 0;
 	argv0 = argv[0];
-	cpu = getenv("cputype");
+	cpu = getenv(ENV_CPUTYPE);
 	if(cpu == 0)
 		error("can't get cputype");
 

sys/src/cmd/ip/listen1.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 
 int verbose;

sys/src/cmd/ip/timesync.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 #include <ip.h>
 #include <mp.h>
@@ -249,7 +250,7 @@ main(int argc, char **argv)
 	fmtinstall('E', eipfmt);
 	fmtinstall('I', eipfmt);
 	fmtinstall('V', eipfmt);
-	sysid = getenv("sysname");
+	sysid = getenv(ENV_SYSNAME);
 
 	/* detach from the current namespace */
 	if(debug)

sys/src/cmd/mc.c

@@ -16,10 +16,11 @@
  *	-t suppresses expanding multiple blanks into tabs
  *
  */
-#include	<u.h>
+#include <u.h>
-#include	<lib9.h>
+#include <lib9.h>
-#include	<draw.h>
+#include <envvars.h>
-#include	<bio.h>
+#include <draw.h>
+#include <bio.h>
 
 #define	WIDTH			80
 #define	TAB	4

sys/src/cmd/ndb/cs.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <auth.h>
 #include <9P2000.h>
 #include <bio.h>
@@ -1032,7 +1033,7 @@ ipid(void)
 		 *  is the ip address.  ignore that.
 		 *
 		 */
-		p = getenv("sysname");
+		p = getenv(ENV_SYSNAME);
 		if(p && *p){
 			attr = ipattr(p);
 			if(strcmp(attr, "ip") != 0)

sys/src/cmd/ndb/dblookup.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <ndb.h>
 #include <ip.h>

sys/src/cmd/ndb/inform.c

@@ -1,6 +1,7 @@
 /* RFC2136 DNS inform - necessary for Win2k3 DNS servers */
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <ndb.h>
 #include <ip.h>
@@ -123,8 +124,8 @@ main(int argc, char *argv[])
 	if(argc != 0)
 		usage();
 
-	if((sysname = getenv("sysname")) == nil)
+	if((sysname = getenv(ENV_SYSNAME)) == nil)
-		sysfatal("$sysname not set");
+		sysfatal("$%s not set", ENV_SYSNAME);
 
 	if((db = ndbopen(nil)) == nil)
 		sysfatal("can't open ndb: %r");

sys/src/cmd/rc/rc.h

@@ -8,16 +8,9 @@
  */
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 
 #define ENV_RCARGLIST	"*"
-#define ENV_APID	"apid"
-#define ENV_HOME	"home"
-#define ENV_IFS		"ifs"
-#define ENV_PATH	"path"
-#define ENV_PID		"pid"
-#define ENV_PROMPT	"prompt"
-#define ENV_STATUS	"status"
-#define ENV_CDPATH	"cdpath"
 #define ENV_RCNAME	"rcname"
 #define ENV_RCCMD	"rccmd"
 

sys/src/cmd/rio/fsys.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <draw.h>
 #include <thread.h>
 #include <cursor.h>
@@ -167,7 +168,7 @@ filsysinit(Channel *cxfidalloc)
 	 * Post srv pipe
 	 */
 	snprint(srvpipe, sizeof(srvpipe), "/srv/rio.%s.%d", fs->user, pid);
-	post(srvpipe, "wsys", fs->cfd);
+	post(srvpipe, ENV_WSYS, fs->cfd);
 
 	return fs;
 

sys/src/cmd/rio/rio.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <draw.h>
 #include <thread.h>
 #include <cursor.h>
@@ -172,7 +173,7 @@ threadmain(int argc, char *argv[])
 		maxtab = 4;
 	free(s);
 
-	s = getenv("cputype");
+	s = getenv(ENV_CPUTYPE);
 	if(s){
 		snprint(buf, sizeof(buf), "/arch/%s/aux/rio", s);
 		bind(buf, "/cmd", MBEFORE);

sys/src/cmd/sam/plan9.c

@@ -26,7 +26,6 @@ Rune *right[]= {
 
 char	RSAM[] = "sam";
 char	SAMTERM[] = "/cmd/aux/samterm";
-char	HOME[] = "home";
 char	TMPDIR[] = "/tmp";
 char	SH[] = "rc";
 char	SHPATH[] = "/cmd/rc";

sys/src/cmd/sam/sam.c

@@ -83,7 +83,7 @@ void main(int argc, char *argv[])
 	Strinit0(&rhs);
 	Strinit0(&curwd);
 	Strinit0(&plan9cmd);
-	home = getenv(HOME);
+	home = getenv(ENV_HOME);
 	disk = diskinit();
 	if(home == 0)
 		home = "/";

sys/src/cmd/sam/sam.h

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <plumb.h>
 #include "errors.h"
 
@@ -353,7 +354,6 @@ extern Rune	*right[];
 
 extern char	RSAM[];		/* system dependent */
 extern char	SAMTERM[];
-extern char	HOME[];
 extern char	TMPDIR[];
 extern char	SH[];
 extern char	SHPATH[];

sys/src/cmd/samterm/plan9.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <libc.h>
+#include <envvars.h>
 #include <draw.h>
 #include <thread.h>
 #include <mouse.h>

sys/src/cmd/stats.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <ctype.h>
 #include <draw.h>
 #include <event.h>
@@ -1236,7 +1237,7 @@ main(int argc, char *argv[])
 	quotefmtinstall();
 
 	nmach = 1;
-	mysysname = getenv("sysname");
+	mysysname = getenv(ENV_SYSNAME);
 	if(mysysname == nil){
 		fprint(2, "stats: can't find $sysname: %r\n");
 		exits("sysname");

sys/src/kern/amd64/main.c

@@ -22,6 +22,7 @@
 #include "fns.h"
 #include "ureg.h"
 #include "pool.h"
+#include "envvars.h"
 
 #include "io.h"
 #include "apic.h"
@@ -374,11 +375,11 @@ init0(void)
 		jehanne_snprint(buf, sizeof(buf), "%s %s", "AMD64", conffile);
 		loadenv(oargc, oargv);
 		ksetenv("terminal", buf, 0);
-		ksetenv("cputype", "amd64", 0);
+		ksetenv(ENV_CPUTYPE, "amd64", 0);
 		if(cpuserver)
-			ksetenv("service", "cpu", 0);
+			ksetenv(ENV_SERVICE, "cpu", 0);
 		else
-			ksetenv("service", "terminal", 0);
+			ksetenv(ENV_SERVICE, "terminal", 0);
 		poperror();
 	}
 	kproc("alarm", alarmkproc, 0);

sys/src/kern/boot/boot.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <libc.h>
+#include <envvars.h>
 #include <auth.h>
 #include <9P2000.h>
 #include "../boot/boot.h"

sys/src/kern/boot/bootauth.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <libc.h>
+#include <envvars.h>
 #include <auth.h>
 #include <9P2000.h>
 #include "../boot/boot.h"
@@ -22,7 +23,7 @@ authentication(int cpuflag)
 	char *argv[16], **av;
 	int ac;
 
-	if(jehanne_access(factotumPath, AEXEC) < 0 || jehanne_getenv("user") != nil){
+	if(jehanne_access(factotumPath, AEXEC) < 0 || jehanne_getenv(ENV_USER) != nil){
 		glenda();
 		return;
 	}
@@ -69,7 +70,7 @@ glenda(void)
 	int fd;
 	char *s;
 
-	s = jehanne_getenv("user");
+	s = jehanne_getenv(ENV_USER);
 	if(s == nil)
 		s = "glenda";
 

sys/src/lib/auth/newns.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <auth.h>
 #include <authsrv.h>
@@ -65,9 +66,9 @@ buildns(int newns, char *user, char *file)
 	}
 	if(newns){
 		rfork(RFENVG|RFCNAMEG);
-		setenv("user", user);
+		setenv(ENV_USER, user);
 		snprint(home, sizeof home, "/usr/%s", user);
-		setenv("home", home);
+		setenv(ENV_HOME, home);
 	}
 
 	cdroot = nsfile(newns ? "newns" : "addns", b, rpc);

sys/src/lib/authsrv/readnvram.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <authsrv.h>
 
 static int32_t	finddosfile(int, char*);
@@ -137,7 +138,7 @@ findnvram(Nvrwhere *locp)
 	if (nvrfile == nil)
 		nvrfile = getenv("nvram");
 	if (cputype == nil)
-		cputype = getenv("cputype");
+		cputype = getenv(ENV_CPUTYPE);
 	if(cputype == nil)
 		cputype = strdup("mips");
 	if(strcmp(cputype, "386")==0 || strcmp(cputype, "amd64")==0 || strcmp(cputype, "alpha")==0) {

sys/src/lib/disk/proto.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <auth.h>
 #include <9P2000.h>

sys/src/lib/draw/newwindow.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <draw.h>
 
 /* Connect us to new window, if possible */
@@ -19,7 +20,7 @@ newwindow(char *str)
 	char *wsys;
 	char buf[256];
 
-	wsys = getenv("wsys");
+	wsys = getenv(ENV_WSYS);
 	if(wsys == nil)
 		return -1;
 	fd = open(wsys, ORDWR);

sys/src/lib/draw/scroll.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <draw.h>
 
 int

sys/src/lib/ndb/ndbopen.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <bio.h>
 #include <ctype.h>
 #include <ndb.h>

sys/src/lib/plumb/mesg.c

@@ -9,6 +9,7 @@
 
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include "plumb.h"
 
 int

sys/src/lib/posix/environment.c

@@ -17,6 +17,7 @@
  */
 #include <u.h>
 #include <lib9.h>
+#include <envvars.h>
 #include <posix.h>
 #include "internal.h"