utils: refactor set_home_env

Use the return value from fgetpwent_r as error value.
Reference:
https://man7.org/linux/man-pages/man3/fgetpwent_r.3.html#RETURN_VALUE

Remove ENOTSUP check as it is not needed since
containers@6ed7bab

Closes: containers#2010

Signed-off-by: Erik Sjölund <erik.sjolund@gmail.com>

Author: eriksjolund

src/libcrun/container.c

@@ -1186,7 +1186,7 @@ setup_environment (runtime_spec_schema_config_schema *def, uid_t container_uid,
   if (getenv ("HOME") == NULL)
     {
       ret = set_home_env (container_uid);
-      if (UNLIKELY (ret < 0 && errno != ENOTSUP))
+      if (UNLIKELY (ret < 0))
         {
           setenv ("HOME", "/", 1);
           libcrun_warning ("cannot detect HOME environment variable, setting default");
@@ -3689,7 +3689,7 @@ exec_process_entrypoint (libcrun_context_t *context,
   if (getenv ("HOME") == NULL)
     {
       ret = set_home_env (container_uid);
-      if (UNLIKELY (ret < 0 && errno != ENOTSUP))
+      if (UNLIKELY (ret < 0))
         {
           setenv ("HOME", "/", 1);
           libcrun_warning ("cannot detect HOME environment variable, setting default");

src/libcrun/utils.c

@@ -1447,7 +1447,6 @@ set_home_env (uid_t id)
   cleanup_free char *buf = NULL;
   long buf_size;
   cleanup_file FILE *stream = NULL;
-  int ret = -1;
 
   buf_size = sysconf (_SC_GETPW_R_SIZE_MAX);
   if (buf_size < 0)
@@ -1457,17 +1456,21 @@ set_home_env (uid_t id)
 
   stream = fopen ("/etc/passwd", "re");
   if (stream == NULL)
-    goto error;
+    return -1;
 
   for (;;)
     {
       struct passwd *ret_pw = NULL;
 
-      ret = fgetpwent_r (stream, &pwd, buf, buf_size, &ret_pw);
+      int ret = fgetpwent_r (stream, &pwd, buf, buf_size, &ret_pw);
       if (UNLIKELY (ret != 0))
         {
-          if (errno != ERANGE)
-            goto error;
+          if (ret != ERANGE)
+            {
+              /* Let callers handle the error if the user was not found. */
+              errno = ret;
+              return -1;
+            }
 
           buf_size *= 2;
           buf = xrealloc (buf, buf_size);
@@ -1480,10 +1483,6 @@ set_home_env (uid_t id)
           return 0;
         }
     }
-
-error:
-  /* Let callers handle the error if the user was not found. */
-  return ret ? -errno : 0;
 }
 
 /*if subuid or subgid exist, take the first range for the user */