1 files changed, 94 insertions, 0 deletions
diff --git a/docs/examples/crypt_log_usage.c b/docs/examples/crypt_log_usage.c
new file mode 100644
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--- /dev/null
+++ b/docs/examples/crypt_log_usage.c
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+/*
+ * libcryptsetup API log example
+ *
+ * Copyright (C) 2011-2021 Red Hat, Inc. All rights reserved.
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this file; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <libcryptsetup.h>
+
+/*
+ * This is an example of crypt_set_log_callback API callback.
+ *
+ */
+static void simple_syslog_wrapper(int level, const char *msg, void *usrptr)
+{
+	const char *prefix = (const char *)usrptr;
+	int priority;
+
+	switch(level) {
+		case CRYPT_LOG_NORMAL:  priority = LOG_NOTICE; break;
+		case CRYPT_LOG_ERROR:   priority = LOG_ERR;    break;
+		case CRYPT_LOG_VERBOSE: priority = LOG_INFO;   break;
+		case CRYPT_LOG_DEBUG:   priority = LOG_DEBUG;  break;
+		default:
+			fprintf(stderr, "Unsupported log level requested!\n");
+			return;
+	}
+
+	if (prefix)
+		syslog(priority, "%s:%s", prefix, msg);
+	else
+		syslog(priority, "%s", msg);
+}
+
+int main(void)
+{
+	struct crypt_device *cd;
+	char usrprefix[] = "cslog_example";
+	int r;
+
+	if (geteuid()) {
+		printf("Using of libcryptsetup requires super user privileges.\n");
+		return 1;
+	}
+
+	openlog("cryptsetup", LOG_CONS | LOG_PID, LOG_USER);
+
+	/* Initialize empty crypt device context */
+	r = crypt_init(&cd, NULL);
+	if (r < 0) {
+		printf("crypt_init() failed.\n");
+		return 2;
+	}
+
+	/* crypt_set_log_callback() - register a log callback for crypt context */
+	crypt_set_log_callback(cd, &simple_syslog_wrapper, (void *)usrprefix);
+
+	/* send messages ithrough the crypt_log() interface */
+	crypt_log(cd, CRYPT_LOG_NORMAL, "This is normal log message");
+	crypt_log(cd, CRYPT_LOG_ERROR, "This is error log message");
+	crypt_log(cd, CRYPT_LOG_VERBOSE, "This is verbose log message");
+	crypt_log(cd, CRYPT_LOG_DEBUG, "This is debug message");
+
+	/* release crypt context */
+	crypt_free(cd);
+
+	/* Initialize default (global) log callback */
+	crypt_set_log_callback(NULL, &simple_syslog_wrapper, NULL);
+
+	crypt_log(NULL, CRYPT_LOG_NORMAL, "This is normal log message");
+	crypt_log(NULL, CRYPT_LOG_ERROR, "This is error log message");
+	crypt_log(NULL, CRYPT_LOG_VERBOSE, "This is verbose log message");
+	crypt_log(NULL, CRYPT_LOG_DEBUG, "This is debug message");
+
+	closelog();
+	return 0;
+}