posix: pthread: add logging to pthread key

To align with other supported POSIX features, add logging to
pthread key to provide better error reporting and diagnostics.

Signed-off-by: Christopher Friedt <cfriedt@meta.com>

lib/posix/key.c

diff --git a/lib/posix/key.c b/lib/posix/key.c
index 698088e..9c32c95 100644
--- a/lib/posix/key.c
+++ b/lib/posix/key.c
@@ -7,6 +7,7 @@
 #include "posix_internal.h"
 
 #include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
 #include <zephyr/posix/pthread.h>
 #include <zephyr/posix/pthread_key.h>
 #include <zephyr/sys/bitarray.h>
@@ -17,6 +18,8 @@
 	pthread_thread_data thread_data;
 };
 
+LOG_MODULE_REGISTER(pthread_key, CONFIG_PTHREAD_KEY_LOG_LEVEL);
+
 static struct k_spinlock pthread_key_lock;
 
 /* This is non-standard (i.e. an implementation detail) */
@@ -50,16 +53,19 @@
 
 	/* if the provided cond does not claim to be initialized, its invalid */
 	if (!is_pthread_obj_initialized(key)) {
+		LOG_ERR("Key is uninitialized (%x)", key);
 		return NULL;
 	}
 
 	/* Mask off the MSB to get the actual bit index */
 	if (sys_bitarray_test_bit(&posix_key_bitarray, bit, &actually_initialized) < 0) {
+		LOG_ERR("Key is invalid (%x)", key);
 		return NULL;
 	}
 
 	if (actually_initialized == 0) {
 		/* The cond claims to be initialized but is actually not */
+		LOG_ERR("Key claims to be initialized (%x)", key);
 		return NULL;
 	}
 
@@ -110,6 +116,7 @@
 	sys_slist_init(&(new_key->key_data_l));
 
 	new_key->destructor = destructor;
+	LOG_DBG("Initialized key %p (%x)", new_key, *key);
 
 	return 0;
 }
@@ -146,6 +153,7 @@
 
 		/* Deallocate the object's memory */
 		k_free((void *)key_data);
+		LOG_DBG("Freed key data %p for key %x in thread %x", key_data, key, pthread_self());
 	}
 
 	bit = posix_key_to_offset(key_obj);
@@ -154,6 +162,8 @@
 
 	k_spin_unlock(&pthread_key_lock, key_key);
 
+	LOG_DBG("Deleted key %p (%x)", key_obj, key);
+
 	return 0;
 }
 
@@ -194,6 +204,8 @@
 				 * associate thread specific data
 				 */
 				thread_spec_data->spec_data = (void *)value;
+				LOG_DBG("Paired key %x to value %p for thread %x", key, value,
+					pthread_self());
 				goto out;
 			}
 	}
@@ -202,10 +214,14 @@
 		key_data = k_malloc(sizeof(struct pthread_key_data));
 
 		if (key_data == NULL) {
+			LOG_ERR("Failed to allocate key data for key %x", key);
 			retval = ENOMEM;
 			goto out;
 		}
 
+		LOG_DBG("Allocated key data %p for key %x in thread %x", key_data, key,
+			pthread_self());
+
 		/* Associate thread specific data, initialize new key */
 		key_data->thread_data.key = key_obj;
 		key_data->thread_data.spec_data = (void *)value;
@@ -215,6 +231,8 @@
 
 		/* Append new key data to the key object's list */
 		sys_slist_append(&(key_obj->key_data_l), (sys_snode_t *)key_data);
+
+		LOG_DBG("Paired key %x to value %p for thread %x", key, value, pthread_self());
 	}
 
 out: