From 8744a55869e9d0288bebf8f340d5186dc99922e9 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Sat, 21 Dec 2019 14:40:23 +0000
Subject: lt_dlerror(): initial implementation and integration.

---
 src/core/lt_core.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 3 deletions(-)

(limited to 'src/core/lt_core.c')

diff --git a/src/core/lt_core.c b/src/core/lt_core.c
index df9f58f..8c26ff3 100644
--- a/src/core/lt_core.c
+++ b/src/core/lt_core.c
@@ -4,12 +4,36 @@
 /*  Released under the Standard MIT License; see COPYING.SLTDL.    */
 /*******************************************************************/
 
+#include <dlfcn.h>
+#include <errno.h>
 #include <limits.h>
+#include <stdlib.h>
+#include <string.h>
 #include <pthread.h>
+
 #include <sltdl/sltdl.h>
+#include "sltdl_core.h"
+
+static const char * lt_dlerror_desc[] = {
+	[SLTDL_OK]                              = 0,
+	[SLTDL_SYSTEM_ERROR]                    = 0,
+	[SLTDL_DLFCN_ERROR]                     = 0,
+	[SLTDL_SLTDL_ERROR]                     = "sltdl internal error",
+	[SLTDL_DLEXIT_REF_COUNT]                = "lt_dlexit() reference count already zero",
+	[SLTDL_MODULE_REF_COUNT]                = "module reference count already zero",
+	[SLTDL_MODULE_PTR_INVALID]              = "module handle invalid",
+	[SLTDL_PATH_INVALID_FIRST_CHAR]         = "invalid path (does not begin with a forward slash)",
+	[SLTDL_PATH_INVALID_SEPARATTOR_CHAR]    = "invalid path (separator character is not a colon)",
+	[SLTDL_PATH_INVALID_MARK]               = "invalid path (mark not within range)",
+	[SLTDL_PATH_INVALID_LEN]                = "invalid path (string too long)",
+	[SLTDL_PATH_NO_ENTRY]                   = "invalid path (not found)",
+};
 
-static int             lt_refs = 0;
-static pthread_mutex_t lt_lock = PTHREAD_MUTEX_INITIALIZER;
+static int             lt_refs  = 0;
+static int             lt_error = 0;
+static int             lt_errno = 0;
+static char *          lt_dlerr = 0;
+static pthread_mutex_t lt_lock  = PTHREAD_MUTEX_INITIALIZER;
 
 int lt_dlinit(void)
 {
@@ -28,6 +52,7 @@ int lt_dlexit(void)
 		return 1;
 
 	if (!lt_refs) {
+		lt_error = SLTDL_DLEXIT_REF_COUNT;
 		pthread_mutex_unlock(&lt_lock);
 		return 1;
 	}
@@ -48,8 +73,57 @@ void lt_slock(void)
 	} while (locked);
 }
 
-int lt_sunlock(int ret)
+int lt_sunlock(int ret, int error)
 {
+	if (error ==  0) {
+		pthread_mutex_unlock(&lt_lock);
+		return 0;
+	}
+
+	if ((error < 0) || (error >= SLTDL_ERROR_CAP)) {
+		error = SLTDL_SLTDL_ERROR;
+
+	} else if (error == SLTDL_SYSTEM_ERROR) {
+		lt_errno = errno;
+
+	} else if (error == SLTDL_DLFCN_ERROR) {
+		if (lt_dlerr)
+			free(lt_dlerr);
+
+		lt_dlerr = strdup(dlerror());
+	}
+
+	lt_error = error;
 	pthread_mutex_unlock(&lt_lock);
 	return ret;
 }
+
+const char * lt_dlerror(void)
+{
+	const char * errdesc;
+
+	lt_slock();
+
+	switch (lt_error) {
+		case SLTDL_OK:
+			errdesc = 0;
+			break;
+
+		case SLTDL_SYSTEM_ERROR:
+			errdesc = strerror(lt_errno);
+			break;
+
+		case SLTDL_DLFCN_ERROR:
+			errdesc = lt_dlerr;
+			break;
+
+		default:
+			errdesc = lt_dlerror_desc[lt_error];
+			break;
+	}
+
+	lt_error = 0;
+	lt_sunlock(0,0);
+
+	return errdesc;
+}
-- 
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