Make putenv() fully conforms to Open Group specs Issue 6

(also IEEE Std 1003.1-2001)

The specs explicitly says that altering passed string
should change the environment, i.e. putenv() directly puts its arg
into environment (unlike setenv() which just copies it there).
It means that putenv() can't be implemented via setenv()
(like we have before) at all. Putenv() value lives (allows modifying)
up to the next putenv() or setenv() call.

lib/libc/stdlib/getenv.3

@@ -88,11 +88,17 @@ to the given
 .Pp
 The
 .Fn putenv
-function takes an argument of the form ``name=value'' and is
-equivalent to:
-.Bd -literal -offset indent
-setenv(name, value, 1);
-.Ed
+function takes an argument of the form ``name=value'' and
+puts it directly into the current environment.
+If the variable
+.Fa name
+does not exist in the list,
+it is inserted with the given
+.Fa value .
+If the variable
+.Fa name
+does exist, it is reset to the given
+.Fa value .
 .Pp
 The
 .Fn unsetenv
@@ -145,7 +151,8 @@ The
 function conforms to
 .St -isoC .
 The
-.Fn setenv
+.Fn setenv ,
+.Fn putenv
 and
 .Fn unsetenv
 functions conforms to

lib/libc/stdlib/getenv.c

@@ -43,7 +43,8 @@ inline char *__findenv(const char *, int *);
  * __findenv --
  *	Returns pointer to value associated with name, if any, else NULL.
  *	Sets offset to be the offset of the name/value combination in the
- *	environmental array, for use by setenv(3) and unsetenv(3).
+ *      environmental array, for use by putenv(3), setenv(3) and unsetenv(3).
+ *	Explicitly removes '=' in argument name.
  *
  *	This routine *should* be a static; don't use it.
  */
@@ -59,7 +60,9 @@ __findenv(name, offset)
 
 	if (environ == NULL)
 		return (NULL);
-	len = strlen(name);
+	for (np = name; *np && *np != '='; ++np)
+		continue;
+	len = np - name;
 	for (p = environ; (cp = *p) != NULL; ++p) {
 		for (np = name, i = len; i && *cp; i--)
 			if (*cp++ != *np++)

lib/libc/stdlib/putenv.c

@@ -37,24 +37,46 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <string.h>
 
+extern char **__alloced;        /* if allocated space before */
+
+char *__findenv(const char *, int *);
+
 int
 putenv(str)
 	char *str;
 {
-	char *p, *equal;
-	int rval, serrno;
+	extern char **environ;
+	char *eq;
+	int offset;
 
-	if ((p = strdup(str)) == NULL)
-		return (-1);
-	if ((equal = index(p, '=')) == NULL) {
-		(void)free(p);
+	if (str == NULL || (eq = strchr(str, '=')) == NULL || eq == str) {
 		errno = EINVAL;
 		return (-1);
 	}
-	*equal = '\0';
-	rval = setenv(p, equal + 1, 1);
-	serrno = errno;
-	(void)free(p);
-	errno = serrno;
-	return (rval);
+
+	/* Trimmed version of setenv(3). */
+	if (__findenv(str, &offset) == NULL) {
+		int cnt;
+		char **p;
+
+		for (p = environ, cnt = 0; *p; ++p, ++cnt);
+		if (__alloced == environ) {                       /* just increase size */
+			p = (char **)realloc((char *)environ,
+			    (size_t)(sizeof(char *) * (cnt + 2)));
+			if (!p)
+				return (-1);
+		}
+		else {				/* get new space */
+						/* copy old entries into it */
+			p = (char **)malloc((size_t)(sizeof(char *) * (cnt + 2)));
+			if (!p)
+				return (-1);
+			bcopy(environ, p, cnt * sizeof(char *));
+		}
+		__alloced = environ = p;
+		environ[cnt + 1] = NULL;
+		offset = cnt;
+	}
+	environ[offset] = str;
+	return (0);
 }

lib/libc/stdlib/setenv.c

@@ -38,6 +38,8 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <string.h>
 
+char **__alloced;       /* if allocated space before */
+
 char *__findenv(const char *, int *);
 
 /*
@@ -52,7 +54,6 @@ setenv(name, value, rewrite)
 	int rewrite;
 {
 	extern char **environ;
-	static char **alloced;			/* if allocated space before */
 	char *c;
 	int l_value, offset;
 
@@ -74,26 +75,25 @@ setenv(name, value, rewrite)
 		char **p;
 
 		for (p = environ, cnt = 0; *p; ++p, ++cnt);
-		if (alloced == environ) {			/* just increase size */
+		if (__alloced == environ) {                       /* just increase size */
 			p = (char **)realloc((char *)environ,
 			    (size_t)(sizeof(char *) * (cnt + 2)));
 			if (!p)
 				return (-1);
-			alloced = environ = p;
 		}
 		else {				/* get new space */
 						/* copy old entries into it */
-			p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
+			p = (char **)malloc((size_t)(sizeof(char *) * (cnt + 2)));
 			if (!p)
 				return (-1);
 			bcopy(environ, p, cnt * sizeof(char *));
-			alloced = environ = p;
 		}
+		__alloced = environ = p;
 		environ[cnt + 1] = NULL;
 		offset = cnt;
 	}
 	if (!(environ[offset] =			/* name + `=' + value */
-	    malloc((size_t)(strlen(name) + l_value + 2))))
+	    (char *)malloc((size_t)(strlen(name) + l_value + 2))))
 		return (-1);
 	for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
 	for (*c++ = '='; (*c++ = *value++); );