util: Add function os_get_option_dup and os_get_option_secure_dup for latter use

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Acked-by: Antonio Ospite <antonio.ospite@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38128>

src/util/os_misc.c

@@ -239,12 +239,32 @@ os_get_option(const char *name)
    return os_get_option_internal(name, false);
 }
 
+char *
+os_get_option_dup(const char *name)
+{
+   const char *opt = os_get_option_internal(name, false);
+   if (opt) {
+      return strdup(opt);
+   }
+   return NULL;
+}
+
 const char *
 os_get_option_secure(const char *name)
 {
    return os_get_option_internal(name, true);
 }
 
+char *
+os_get_option_secure_dup(const char *name)
+{
+   const char *opt = os_get_option_internal(name, true);
+   if (opt) {
+      return strdup(opt);
+   }
+   return NULL;
+}
+
 static struct hash_table *options_tbl;
 static bool options_tbl_exited = false;
 static simple_mtx_t options_tbl_mtx = SIMPLE_MTX_INITIALIZER;

src/util/os_misc.h

@@ -90,6 +90,16 @@ os_log_message(const char *message);
 const char *
 os_get_option(const char *name);
 
+/*
+ * Equivalent to os_get_option except the return value need to be `free()`
+ * os_get_option is not safe when the returned value is not immediately used.
+ * E.g.
+ *  1. when multiple consecutive calls to os_get_option are performed before using the returned values
+ *  2. when the value returned by os_get_option is assigned to a struct member
+ */
+char *
+os_get_option_dup(const char *name);
+
 /*
  * Get an option. Should return NULL if specified option is not set.
  * Same as `os_get_option()` but uses `secure_getenv()` instead of `getenv()`
@@ -97,6 +107,16 @@ os_get_option(const char *name);
 const char *
 os_get_option_secure(const char *name);
 
+/*
+ * Equivalent to os_get_option_secure except the return value need to be `free()`
+ * os_get_option_secure is not safe when the returned value is not immediately used.
+ * E.g.
+ *  1. when multiple consecutive calls to os_get_option_secure are performed before using the returned values
+ *  2. when the value returned by os_get_option_secure is assigned to a struct member
+ */
+char *
+os_get_option_secure_dup(const char *name);
+
 /*
  * Get an option. Should return NULL if specified option is not set.
  * It's will save the option into hash table for the first time, and