uuid: Add module for UUID generation

This commit allow modules of afb-daemon to request UUID.

This introduce an abstraction above libuuid for 3 reasons:

 1. Using uuid had bad side effect inthe past because it
    required enought entropy at start time, leading to hanging
    initialisations in wait for enough entropy.

 2. Solving bug SPEC-2625 will require use of UUID.

 3. Porting to systems that haven't libuuid is made more
    easy after that.

Bug-AGL: SPEC-2625

Change-Id: I27d8b611946686dea6fab250697afe9b89aac869
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

4 files changed, 125 insertions, 70 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 3b444a0b..ee0adb44 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -123,6 +123,7 @@ SET(AFB_LIB_SOURCES
 	sig-monitor.c
 	subpath.c
 	systemd.c
+	uuid.c
 	verbose.c
 	watchdog.c
 	websock.c
diff --git a/src/afb-session.c b/src/afb-session.c
index 70e8c3cd..1bdb59db 100644
--- a/src/afb-session.c
+++ b/src/afb-session.c
@@ -24,16 +24,14 @@
 #include <stdint.h>
 #include <limits.h>
 #include <string.h>
-#include <uuid/uuid.h>
 #include <errno.h>
-#include <unistd.h>
 
 #include "afb-session.h"
 #include "afb-hook.h"
 #include "verbose.h"
 #include "pearson.h"
+#include "uuid.h"
 
-#define SIZEUUID	37
 #define HEADCOUNT	16
 #define COOKIECOUNT	8
 #define COOKIEMASK	(COOKIECOUNT - 1)
@@ -69,8 +67,8 @@ struct afb_session
 	uint8_t closed: 1;      /**< is the session closed ? */
 	uint8_t autoclose: 1;   /**< close the session when unreferenced */
 	uint8_t notinset: 1;	/**< session removed from the set of sessions */
-	char uuid[SIZEUUID];    /**< long term authentication of remote client */
-	char token[SIZEUUID];   /**< short term authentication of remote client */
+	uuid_stringz_t uuid;    /**< long term authentication of remote client */
+	uuid_stringz_t token;   /**< short term authentication of remote client */
 };
 
 /**
@@ -81,7 +79,7 @@ static struct {
 	int max;                /**< maximum count of sessions */
 	int timeout;            /**< common initial timeout */
 	struct afb_session *heads[HEADCOUNT]; /**< sessions */
-	char initok[SIZEUUID];  /**< common initial token */
+	uuid_stringz_t initok;  /**< common initial token */
 	pthread_mutex_t mutex;  /**< declare a mutex to protect hash table */
 } sessions = {
 	.count = 0,
@@ -102,65 +100,6 @@ static inline time_t time_now()
 	return ts.tv_sec;
 }
 
-/**
- * generate a new fresh 'uuid'
- */
-static void new_uuid(char uuid[SIZEUUID])
-{
-	uuid_t newuuid;
-
-#if defined(USE_UUID_GENERATE)
-	uuid_generate(newuuid);
-#else
-	struct timespec ts;
-	static uint16_t pid;
-	static uint16_t counter;
-	static char state[32];
-	static struct random_data rdata;
-
-	int32_t x;
-	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
-	if (pid == 0) {
-		pid = (uint16_t)getpid();
-		counter = (uint16_t)(ts.tv_nsec >> 8);
-		rdata.state = NULL;
-		initstate_r((((unsigned)pid) << 16) + ((unsigned)counter),
-					state, sizeof state, &rdata);
-	}
-	ts.tv_nsec ^= (long)ts.tv_sec;
-	if (++counter == 0)
-		counter = 1;
-
-	newuuid[0] = (char)(ts.tv_nsec >> 24);
-	newuuid[1] = (char)(ts.tv_nsec >> 16);
-	newuuid[2] = (char)(ts.tv_nsec >> 8);
-	newuuid[3] = (char)(ts.tv_nsec);
-
-	newuuid[4] = (char)(pid >> 8);
-	newuuid[5] = (char)(pid);
-
-	random_r(&rdata, &x);
-	newuuid[6] = (char)(((x >> 16) & 0x0f) | 0x40); /* pseudo-random version */
-	newuuid[7] = (char)(x >> 8);
-
-	random_r(&rdata, &x);
-	newuuid[8] = (char)(((x >> 16) & 0x3f) | 0x80); /* variant RFC4122 */
-	newuuid[9] = (char)(x >> 8);
-
-	random_r(&rdata, &x);
-	newuuid[10] = (char)(x >> 16);
-	newuuid[11] = (char)(x >> 8);
-
-	random_r(&rdata, &x);
-	newuuid[12] = (char)(x >> 16);
-	newuuid[13] = (char)(x >> 8);
-
-	newuuid[14] = (char)(counter >> 8);
-	newuuid[15] = (char)(counter);
-#endif
-	uuid_unparse_lower(newuuid, uuid);
-}
-
 /* lock the set of sessions for exclusive access */
 static inline void sessionset_lock()
 {
@@ -206,12 +145,12 @@ static int sessionset_add(struct afb_session *session, uint8_t hashidx)
 }
 
 /* make a new uuid not used in the set of sessions */
-static uint8_t sessionset_make_uuid (char uuid[SIZEUUID])
+static uint8_t sessionset_make_uuid (uuid_stringz_t uuid)
 {
 	uint8_t hashidx;
 
 	do {
-		new_uuid(uuid);
+		uuid_new_stringz(uuid);
 		hashidx = pearson4(uuid);
 	} while(sessionset_search(uuid, hashidx));
 	return hashidx;
@@ -384,7 +323,7 @@ int afb_session_init (int max_session_count, int timeout, const char *initok)
 	sessions.max = max_session_count;
 	sessions.timeout = timeout;
 	if (initok == NULL)
-		new_uuid(sessions.initok);
+		uuid_new_stringz(sessions.initok);
 	else
 		strcpy(sessions.initok, initok);
 	sessionset_unlock();
@@ -480,7 +419,7 @@ int afb_session_what_remains(struct afb_session *session)
 /* This function will return exiting session or newly created session */
 struct afb_session *afb_session_get (const char *uuid, int timeout, int *created)
 {
-	char _uuid_[SIZEUUID];
+	uuid_stringz_t _uuid_;
 	uint8_t hashidx;
 	struct afb_session *session;
 	time_t now;
@@ -598,7 +537,7 @@ int afb_session_check_token (struct afb_session *session, const char *token)
 void afb_session_new_token (struct afb_session *session)
 {
 	session_lock(session);
-	new_uuid(session->token);
+	uuid_new_stringz(session->token);
 	session_update_expiration(session, NOW);
 #if WITH_AFB_HOOK
 	afb_hook_session_renew(session);
diff --git a/src/uuid.c b/src/uuid.c
new file mode 100644
index 00000000..c682080f
--- /dev/null
+++ b/src/uuid.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2016-2019 "IoT.bzh"
+ * Author: José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <uuid/uuid.h>
+
+#include "uuid.h"
+
+/**
+ * generate a new fresh 'uuid'
+ */
+void uuid_new_binary(uuid_binary_t uuid)
+{
+#if defined(USE_UUID_GENERATE)
+	uuid_generate(uuid);
+#else
+	struct timespec ts;
+	static uint16_t pid;
+	static uint16_t counter;
+	static char state[32];
+	static struct random_data rdata;
+
+	int32_t x;
+	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+	if (pid == 0) {
+		pid = (uint16_t)getpid();
+		counter = (uint16_t)(ts.tv_nsec >> 8);
+		rdata.state = NULL;
+		initstate_r((((unsigned)pid) << 16) + ((unsigned)counter),
+					state, sizeof state, &rdata);
+	}
+	ts.tv_nsec ^= (long)ts.tv_sec;
+	if (++counter == 0)
+		counter = 1;
+
+	uuid[0] = (char)(ts.tv_nsec >> 24);
+	uuid[1] = (char)(ts.tv_nsec >> 16);
+	uuid[2] = (char)(ts.tv_nsec >> 8);
+	uuid[3] = (char)(ts.tv_nsec);
+
+	uuid[4] = (char)(pid >> 8);
+	uuid[5] = (char)(pid);
+
+	random_r(&rdata, &x);
+	uuid[6] = (char)(((x >> 16) & 0x0f) | 0x40); /* pseudo-random version */
+	uuid[7] = (char)(x >> 8);
+
+	random_r(&rdata, &x);
+	uuid[8] = (char)(((x >> 16) & 0x3f) | 0x80); /* variant RFC4122 */
+	uuid[9] = (char)(x >> 8);
+
+	random_r(&rdata, &x);
+	uuid[10] = (char)(x >> 16);
+	uuid[11] = (char)(x >> 8);
+
+	random_r(&rdata, &x);
+	uuid[12] = (char)(x >> 16);
+	uuid[13] = (char)(x >> 8);
+
+	uuid[14] = (char)(counter >> 8);
+	uuid[15] = (char)(counter);
+#endif
+}
+
+void uuid_new_stringz(uuid_stringz_t uuid)
+{
+	uuid_t newuuid;
+	uuid_new_binary(newuuid);
+	uuid_unparse_lower(newuuid, uuid);
+}
diff --git a/src/uuid.h b/src/uuid.h
new file mode 100644
index 00000000..ee467d14
--- /dev/null
+++ b/src/uuid.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2016-2019 "IoT.bzh"
+ * Author: José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#define UUID_BINARY_LENGTH   16
+#define UUID_STRINGZ_LENGTH  37
+
+typedef unsigned char uuid_binary_t[UUID_BINARY_LENGTH];
+typedef char uuid_stringz_t[UUID_STRINGZ_LENGTH];
+
+void uuid_new_binary(uuid_binary_t uuid);
+void uuid_new_stringz(uuid_stringz_t uuid);