libc: rewrite putenv and getenv.

These new implementations

- do several validity check on input parameters
- allow a bit larger variable names (127 bytes, aka sizeof(Proc.genbuf)-1)
- preserve nulls in the content (the original version used to replace
  '\0' with ' '). I can't see why they did, actually.
  See also http://marc.info/?l=9fans&m=148475801229908&w=2

Should also fix CID 155718

qa/lib/c/build.json

@@ -8,6 +8,9 @@
 			"-std=gnu11"
 		],
 		"Install": "/arch/$ARCH/qa/lib/c",
+		"Post": [
+			"cp *.rc $JEHANNE/arch/$ARCH/qa/lib/c/"
+		],
 		"SourceFilesCmd": [
 			"asmscall.c",
 			"cleanname.c",

qa/lib/c/env.rc

@@ -0,0 +1,28 @@
+#!/cmd/rc
+
+# verify that environment variables can have names 127 byte long
+# why 127? because it's the size of genbuf in the kernel's Proc structure
+# minus the ending \0
+
+abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef012345678=10
+if ( ! ~ $abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef012345678 10 ) {
+	echo FAIL: cannot read an environment variable with a long name
+	exit FAIL
+}
+
+# verify that rc lists work
+list=(How now brown cow)
+string=$"list
+
+if( ! ~ $#list 4 ) {
+	echo FAIL: list count does not work on a 4 elements list
+	exit FAIL
+}
+
+if( ! ~ $#string 1 ) {
+	echo FAIL: list count does not work on a single string
+	exit FAIL
+}
+
+echo PASS
+exit PASS

sys/include/libc.h

@@ -46,7 +46,7 @@ extern	int	strncmp(const char*, const char*, int32_t);
 extern	char*	strpbrk(const char*, const char*);
 extern	char*	strrchr(const char*, int);
 extern	char*	strtok(char*, char*);
-extern	int32_t	strlen(const char*);
+extern	int	strlen(const char*);
 extern	int32_t	strspn(const char*, const char*);
 extern	int32_t	strcspn(const char*, const char*);
 extern	char*	strstr(const char*, const char*);

sys/src/lib/c/9sys/getenv.c

@@ -1,12 +1,19 @@
 /*
- * Copyright (C) 2016 Giacomo Tesio <giacomo@tesio.it>
+ * This file is part of Jehanne.
  *
- * This file is part of the UCB release of Plan 9. It is subject to the license
+ * Copyright (C) 2017 Giacomo Tesio <giacomo@tesio.it>
- * terms in the LICENSE file found in the top-level directory of this
+ *
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
+ * Jehanne is free software: you can redistribute it and/or modify
- * part of the UCB release of Plan 9, including this file, may be copied,
+ * it under the terms of the GNU General Public License as published by
- * modified, propagated, or distributed except according to the terms contained
+ * the Free Software Foundation, version 2 of the License.
- * in the LICENSE file.
+ *
+ * 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/>.
  */
 
 #include <u.h>
@@ -15,17 +22,23 @@
 char*
 getenv(const char *name)
 {
-	int r, f;
+	int f;
-	int32_t s;
+	int32_t l;
-	char *ans;
+	char path[127+5+1], *value;
-	char *p, *ep, ename[100];
 
-	if(strchr(name, '/') != nil)
+	assert(name != nil);
-		return nil;
+	if(name[0]=='\0')
-	snprint(ename, sizeof ename, "/env/%s", name);
+		goto BadName;
-	if(strcmp(ename+5, name) != 0)
+	if(strcmp(name, ".")==0 || strcmp(name, "..")==0)
-		return nil;
+		goto BadName;
-	f = open(ename, OREAD);
+	if(strchr(name, '/')!=nil)
+		goto BadName;
+
+	snprint(path, sizeof path, "/env/%s", name);
+	if(strcmp(path+5, name) != 0)
+		goto BadName;
+
+	f = open(path, OREAD);
 	if(f < 0){
 		/* try with #e, in case of a previous rfork(RFCNAMEG)
 		 *
@@ -34,25 +47,24 @@ getenv(const char *name)
 		 * using #ec when the open in #e fails is both
 		 * slow and not flexible enough.
 		 */
-		snprint(ename, sizeof ename, "#e/%s", name);
+		snprint(path, sizeof path, "#e/%s", name);
-		f = open(ename, OREAD);
+		f = open(path, OREAD);
 		if(f < 0)
 			return nil;
 	}
-	s = seek(f, 0, 2);
+	l = seek(f, 0, 2);
-	ans = malloc(s+1);
+	value = malloc(l+1);
-	if(ans) {
+	if(value == nil)
-		setmalloctag(ans, getcallerpc());
+		goto Done;
-		seek(f, 0, 0);
+	setmalloctag(value, getcallerpc());
-		r = read(f, ans, s);
+	seek(f, 0, 0);
-		if(r >= 0) {
+	if(read(f, value, l) >= 0)
-			ep = ans + s - 1;
+		value[l] = '\0';
-			for(p = ans; p < ep; p++)
+Done:
-				if(*p == '\0')
-					*p = ' ';
-			ans[s] = '\0';
-		}
-	}
 	close(f);
-	return ans;
+	return value;
+
+BadName:
+	werrstr("bad env name: '%s'", name);
+	return nil;
 }

sys/src/lib/c/9sys/putenv.c

@@ -1,44 +1,62 @@
 /*
- * Copyright (C) 2016 Giacomo Tesio <giacomo@tesio.it>
+ * This file is part of Jehanne.
  *
- * This file is part of the UCB release of Plan 9. It is subject to the license
+ * Copyright (C) 2016-2017 Giacomo Tesio <giacomo@tesio.it>
- * terms in the LICENSE file found in the top-level directory of this
+ *
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
+ * Jehanne is free software: you can redistribute it and/or modify
- * part of the UCB release of Plan 9, including this file, may be copied,
+ * it under the terms of the GNU General Public License as published by
- * modified, propagated, or distributed except according to the terms contained
+ * the Free Software Foundation, version 2 of the License.
- * in the LICENSE file.
+ *
+ * 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/>.
  */
 
 #include <u.h>
 #include <libc.h>
 
 int
-putenv(const char *name, const char *val)
+putenv(const char *name, const char *value)
 {
 	int f;
-	char ename[100];
+	int32_t l;
-	int32_t s;
+	char path[127+5+1];
 
-	if(strchr(name, '/') != nil)
+	assert(name != nil);
-		return -1;
+	assert(value != nil);
-	snprint(ename, sizeof ename, "/env/%s", name);
+	if(name[0]=='\0')
-	if(strcmp(ename+5, name) != 0)
+		goto BadName;
-		return -1;
+	if(strcmp(name, ".")==0 || strcmp(name, "..")==0)
-	f = ocreate(ename, OWRITE, 0664);
+		goto BadName;
+	if(strchr(name, '/')!=nil)
+		goto BadName;
+
+	snprint(path, sizeof path, "/env/%s", name);
+	if(strcmp(path+5, name) != 0)
+		goto BadName;
+
+	f = ocreate(path, OWRITE, 0664);
 	if(f < 0){
 		/* try with #e, in case of a previous rfork(RFCNAMEG)
 		 */
-		snprint(ename, sizeof ename, "#e/%s", name);
+		snprint(path, sizeof path, "#e/%s", name);
-		f = ocreate(ename, OWRITE, 0664);
+		f = ocreate(path, OWRITE, 0664);
 		if(f < 0)
 			return -1;
-		return -1;
 	}
-	s = strlen(val);
+	l = strlen(value);
-	if(write(f, val, s) != s){
+	if(l > 0 && write(f, value, l) != l){
 		close(f);
 		return -1;
 	}
 	close(f);
 	return 0;
+
+BadName:
+	werrstr("bad env name: '%s'", name);
+	return -1;
 }

sys/src/lib/c/port/strlen.c

@@ -10,9 +10,8 @@
 #include <u.h>
 #include <libc.h>
 
-int32_t
+int
 strlen(const char *s)
 {
-
 	return strchr(s, 0) - s;
 }