Add utils_env_var_get_str() to utils_common

Add utils_env_var_get_str() to utils_common.
Use utils_env_var_get_str() inside utils_env_var_has_str()
and utils_is_running_in_proxy_lib().

Signed-off-by: Lukasz Dorau <lukasz.dorau@intel.com>

Author: ldorau

src/utils/utils_common.c

@@ -53,18 +53,9 @@ void utils_align_ptr_down_size_up(void **ptr, size_t *size, size_t alignment) {
     *size = s;
 }
 
-int utils_env_var_has_str(const char *envvar, const char *str) {
+char *utils_env_var_get_str(const char *envvar, const char *str) {
     char *value = getenv(envvar);
-    if (value && strstr(value, str)) {
-        return 1;
-    }
-
-    return 0;
-}
-
-// check if we are running in the proxy library
-int utils_is_running_in_proxy_lib(void) {
-    return utils_env_var_has_str("LD_PRELOAD", "libumf_proxy.so");
+    return value ? strstr(value, str) : NULL;
 }
 
 const char *utils_parse_var(const char *var, const char *option,

src/utils/utils_common.h

@@ -61,8 +61,18 @@ typedef enum umf_purge_advise_t {
 
 #endif /* _WIN32 */
 
+// get the address of the given string in the environment variable (or NULL)
+char *utils_env_var_get_str(const char *envvar, const char *str);
+
 // Check if the environment variable contains the given string.
-int utils_env_var_has_str(const char *envvar, const char *str);
+static inline int utils_env_var_has_str(const char *envvar, const char *str) {
+    return utils_env_var_get_str(envvar, str) ? 1 : 0;
+}
+
+// check if we are running in the proxy library
+static inline int utils_is_running_in_proxy_lib(void) {
+    return utils_env_var_get_str("LD_PRELOAD", "libumf_proxy.so") ? 1 : 0;
+}
 
 // utils_parse_var - Parses var for a prefix,
 //                   optionally identifying a following argument.
@@ -81,9 +91,6 @@ int utils_env_var_has_str(const char *envvar, const char *str);
 const char *utils_parse_var(const char *var, const char *option,
                             const char **extraArg);
 
-// check if we are running in the proxy library
-int utils_is_running_in_proxy_lib(void);
-
 size_t utils_get_page_size(void);
 
 // align a pointer up and a size down