From 8647a3478674979cca582774168a6f220de171ef Mon Sep 17 00:00:00 2001
From: Jose Bollo <jose.bollo@iot.bzh>
Date: Thu, 6 Sep 2018 16:01:20 +0200
Subject: afb-session: Use ad-hoc pseudo-random uuid
The use of the generator given by the lib uuid
implies the use of the system call 'getrandom'
without the flag GRND_NONBLOCK. It has a weird
effect on boot because many binders require
the generation of uuid at the same time but
getrandom is subject to starving.
This introduced a tiny pseudo-random generation
of UUID that does not implies the use of 'getrandom'.
Bug-AGL: SPEC-1655
Change-Id: I5131072881d7a53f0edda9e36762985c96a04550
Signed-off-by: Jose Bollo <jose.bollo@iot.bzh>
---
src/afb-session.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
diff --git a/src/afb-session.c b/src/afb-session.c
index adfed2ad..fdc88fdf 100644
--- a/src/afb-session.c
+++ b/src/afb-session.c
@@ -26,6 +26,7 @@
#include <string.h>
#include <uuid/uuid.h>
#include <errno.h>
+#include <unistd.h>
#include "afb-session.h"
#include "afb-hook.h"
@@ -106,7 +107,56 @@ static inline time_t time_now()
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);
}
--
cgit