1 files changed, 46 insertions, 0 deletions
diff --git a/getkey.c b/getkey.c
new file mode 100644
index 0000000..6e3da12
--- /dev/null
+++ b/getkey.c
@@ -0,0 +1,46 @@
+#define _XOPEN_SOURCE 700
+#include <dirent.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "deonebook.h"
+
+unsigned char *getkey(const char *keystring, const char *device)
+{
+	if (keystring) {
+		static unsigned char key[KEY_SIZE] = "";
+		if (strlen(keystring) != (KEY_SIZE * 2)) {
+			fprintf(stderr, "key must be %d hex characters\n", KEY_SIZE * 2);
+			return NULL;
+		}
+
+		for (size_t i = 0; i < sizeof(key); i++) {
+			char hex[] = { keystring[i * 2], keystring[i * 2 + 1], '\0' };
+			key[i] = (unsigned char)strtoul(hex, NULL, 16);
+		}
+		return key;
+	}
+
+	if (!device) {
+		device = "mmcblk0";
+	} else if (strstr(device, "mmcblk") != device) {
+		fprintf(stderr, "device must be an mmcblk device\n");
+		return NULL;
+	}
+
+	char path[256];
+	snprintf(path, sizeof(path), "/sys/block/%s/device", device);
+	DIR *d = opendir(path);
+	if (d == NULL) {
+		fprintf(stderr, "device '%s' not found\n", device);
+		return NULL;
+	}
+
+	unsigned char *key = genkey(dirfd(d));
+	if (key) {
+		return key;
+	}
+
+	return readkey("./.shm");
+}