set errno when getpw*_r, getgr*_r, and getspnam_r fail

these functions return an error code, and are not explicitly
documented to set errno, but they are nonstandard and the historical
implementations do set errno as well, and some applications expect
this behavior. do likewise for compatibility.

patch by Rudolph Pereira.

src/passwd/getgr_r.c

@@ -34,6 +34,7 @@ static int getgr_r(const char *name, gid_t gid, struct group *gr, char *buf, siz
  	free(mem);
  	free(line);
 	pthread_setcancelstate(cs, 0);
+	if (rv) errno = rv;
 	return rv;
 }
 

src/passwd/getpw_r.c

@@ -27,6 +27,7 @@ static int getpw_r(const char *name, uid_t uid, struct passwd *pw, char *buf, si
 	}
  	free(line);
 	pthread_setcancelstate(cs, 0);
+	if (rv) errno = rv;
 	return rv;
 }
 

src/passwd/getspnam_r.c

@@ -72,14 +72,15 @@ int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct
 
 	/* Disallow potentially-malicious user names */
 	if (*name=='.' || strchr(name, '/') || !l)
-		return EINVAL;
+		return errno = EINVAL;
 
 	/* Buffer size must at least be able to hold name, plus some.. */
-	if (size < l+100) return ERANGE;
+	if (size < l+100)
+		return errno = EINVAL;
 
 	/* Protect against truncation */
 	if (snprintf(path, sizeof path, "/etc/tcb/%s/shadow", name) >= sizeof path)
-		return EINVAL;
+		return errno = EINVAL;
 
 	fd = open(path, O_RDONLY|O_NOFOLLOW|O_NONBLOCK|O_CLOEXEC);
 	if (fd >= 0) {
@@ -112,5 +113,6 @@ int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct
 		break;
 	}
 	pthread_cleanup_pop(1);
+	if (rv) errno = rv;
 	return rv;
 }