diff --git a/ext/standard/filestat.c b/ext/standard/filestat.c
index 4cb7b93745a..0825fa05864 100644
--- a/ext/standard/filestat.c
+++ b/ext/standard/filestat.c
@@ -279,13 +279,25 @@ PHPAPI zend_result php_get_gid_by_name(const char *name, gid_t *gid)
 		struct group *retgrptr;
 		long grbuflen = sysconf(_SC_GETGR_R_SIZE_MAX);
 		char *grbuf;
+		int err;
 
 		if (grbuflen < 1) {
-			return FAILURE;
+			grbuflen = 1024;
 		}
-
+# if ZEND_DEBUG
+		/* Test retry logic */
+		grbuflen = 1;
+# endif
 		grbuf = emalloc(grbuflen);
-		if (getgrnam_r(name, &gr, grbuf, grbuflen, &retgrptr) != 0 || retgrptr == NULL) {
+
+try_again:
+		err = getgrnam_r(name, &gr, grbuf, grbuflen, &retgrptr);
+		if (err != 0 || retgrptr == NULL) {
+			if (err == ERANGE) {
+				grbuflen *= 2;
+				grbuf = erealloc(grbuf, grbuflen);
+				goto try_again;
+			}
 			efree(grbuf);
 			return FAILURE;
 		}
@@ -405,13 +417,25 @@ PHPAPI zend_result php_get_uid_by_name(const char *name, uid_t *uid)
 		struct passwd *retpwptr = NULL;
 		long pwbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 		char *pwbuf;
+		int err;
 
 		if (pwbuflen < 1) {
-			return FAILURE;
+			pwbuflen = 1024;
 		}
-
+# if ZEND_DEBUG
+		/* Test retry logic */
+		pwbuflen = 1;
+# endif
 		pwbuf = emalloc(pwbuflen);
-		if (getpwnam_r(name, &pw, pwbuf, pwbuflen, &retpwptr) != 0 || retpwptr == NULL) {
+
+try_again:
+		err = getpwnam_r(name, &pw, pwbuf, pwbuflen, &retpwptr);
+		if (err != 0 || retpwptr == NULL) {
+			if (err == EAGAIN) {
+				pwbuflen *= 2;
+				pwbuf = erealloc(pwbuf, pwbuflen);
+				goto try_again;
+			}
 			efree(pwbuf);
 			return FAILURE;
 		}
diff --git a/main/fopen_wrappers.c b/main/fopen_wrappers.c
index 5ea432d6cef..99a082846b4 100644
--- a/main/fopen_wrappers.c
+++ b/main/fopen_wrappers.c
@@ -374,26 +374,38 @@ PHPAPI int php_fopen_primary_script(zend_file_handle *file_handle)
 
 		if (s) {			/* if there is no path name after the file, do not bother */
 			char user[32];			/* to try open the directory */
-			struct passwd *pw;
-#if defined(ZTS) && defined(HAVE_GETPWNAM_R) && defined(_SC_GETPW_R_SIZE_MAX)
-			struct passwd pwstruc;
-			long pwbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
-			char *pwbuf;
 
-			if (pwbuflen < 1) {
-				return FAILURE;
-			}
-
-			pwbuf = emalloc(pwbuflen);
-#endif
 			length = s - (path_info + 2);
 			if (length > sizeof(user) - 1) {
 				length = sizeof(user) - 1;
 			}
 			memcpy(user, path_info + 2, length);
 			user[length] = '\0';
+
+			struct passwd *pw;
 #if defined(ZTS) && defined(HAVE_GETPWNAM_R) && defined(_SC_GETPW_R_SIZE_MAX)
-			if (getpwnam_r(user, &pwstruc, pwbuf, pwbuflen, &pw)) {
+			struct passwd pwstruc;
+			long pwbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+			char *pwbuf;
+			int err;
+
+			if (pwbuflen < 1) {
+				pwbuflen = 1024;
+			}
+# if ZEND_DEBUG
+			/* Test retry logic */
+			pwbuflen = 1;
+# endif
+			pwbuf = emalloc(pwbuflen);
+
+try_again:
+			err = getpwnam_r(user, &pwstruc, pwbuf, pwbuflen, &pw);
+			if (err) {
+				if (err == ERANGE) {
+					pwbuflen *= 2;
+					pwbuf = erealloc(pwbuf, pwbuflen);
+					goto try_again;
+				}
 				efree(pwbuf);
 				return FAILURE;
 			}
diff --git a/main/main.c b/main/main.c
index fb20ec2777c..aa80837f657 100644
--- a/main/main.c
+++ b/main/main.c
@@ -1475,12 +1475,25 @@ PHPAPI char *php_get_current_user(void)
 		struct passwd *retpwptr = NULL;
 		int pwbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
 		char *pwbuf;
+		int err;
 
 		if (pwbuflen < 1) {
-			return "";
+			pwbuflen = 1024;
 		}
+# if ZEND_DEBUG
+		/* Test retry logic */
+		pwbuflen = 1;
+# endif
 		pwbuf = emalloc(pwbuflen);
-		if (getpwuid_r(pstat->st_uid, &_pw, pwbuf, pwbuflen, &retpwptr) != 0) {
+
+try_again:
+		err = getpwuid_r(pstat->st_uid, &_pw, pwbuf, pwbuflen, &retpwptr);
+		if (err != 0) {
+			if (err == ERANGE) {
+				pwbuflen *= 2;
+				pwbuf = erealloc(pwbuf, pwbuflen);
+				goto try_again;
+			}
 			efree(pwbuf);
 			return "";
 		}