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clusterGetRandomName() generalized into getRandomHexChars() so that w…

…e can use it for the run_id field as well.
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1 parent 4d3bbf3 commit 44f508f1a81941f298bdb0f2f87c4469094beeb6 @antirez committed Mar 8, 2012
Showing with 52 additions and 15 deletions.
  1. +1 −15 src/cluster.c
  2. +3 −0 src/redis.h
  3. +48 −0 src/util.c
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@@ -19,20 +19,6 @@ int clusterAddSlot(clusterNode *n, int slot);
* Initialization
* -------------------------------------------------------------------------- */
-void clusterGetRandomName(char *p) {
- FILE *fp = fopen("/dev/urandom","r");
- char *charset = "0123456789abcdef";
- int j;
-
- if (fp == NULL || fread(p,REDIS_CLUSTER_NAMELEN,1,fp) == 0) {
- for (j = 0; j < REDIS_CLUSTER_NAMELEN; j++)
- p[j] = rand();
- }
- for (j = 0; j < REDIS_CLUSTER_NAMELEN; j++)
- p[j] = charset[p[j] & 0x0F];
- fclose(fp);
-}
-
int clusterLoadConfig(char *filename) {
FILE *fp = fopen(filename,"r");
char *line;
@@ -304,7 +290,7 @@ clusterNode *createClusterNode(char *nodename, int flags) {
if (nodename)
memcpy(node->name, nodename, REDIS_CLUSTER_NAMELEN);
else
- clusterGetRandomName(node->name);
+ getRandomHexChars(node->name, REDIS_CLUSTER_NAMELEN);
node->flags = flags;
memset(node->slots,0,sizeof(node->slots));
node->numslaves = 0;
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@@ -58,6 +58,8 @@
#define REDIS_REPL_TIMEOUT 60
#define REDIS_REPL_PING_SLAVE_PERIOD 10
+#define REDIS_RUN_ID_SIZE 40
+
/* Protocol and I/O related defines */
#define REDIS_MAX_QUERYBUF_LEN (1024*1024*1024) /* 1GB max query buffer. */
#define REDIS_IOBUF_LEN (1024*16) /* Generic I/O buffer size */
@@ -813,6 +815,7 @@ dictType hashDictType;
/* Utils */
long long ustime(void);
long long mstime(void);
+void getRandomHexChars(char *p, unsigned int len);
/* networking.c -- Networking and Client related operations */
redisClient *createClient(int fd);
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@@ -5,6 +5,8 @@
#include <ctype.h>
#include <limits.h>
#include <math.h>
+#include <unistd.h>
+#include <sys/time.h>
#include "util.h"
@@ -327,6 +329,52 @@ int d2string(char *buf, size_t len, double value) {
return len;
}
+/* Generate the Redis "Run ID", a SHA1-sized random number that identifies a
+ * given execution of Redis, so that if you are talking with an instance
+ * having run_id == A, and you reconnect and it has run_id == B, you can be
+ * sure that it is either a different instance or it was restarted. */
+void getRandomHexChars(char *p, unsigned int len) {
+ FILE *fp = fopen("/dev/urandom","r");
+ char *charset = "0123456789abcdef";
+ unsigned int j;
+
+ if (fp == NULL || fread(p,len,1,fp) == 0) {
+ /* If we can't read from /dev/urandom, do some reasonable effort
+ * in order to create some entropy, since this function is used to
+ * generate run_id and cluster instance IDs */
+ char *x = p;
+ unsigned int l = len;
+ struct timeval tv;
+ pid_t pid = getpid();
+
+ /* Use time and PID to fill the initial array. */
+ gettimeofday(&tv,NULL);
+ if (l >= sizeof(tv.tv_usec)) {
+ memcpy(x,&tv.tv_usec,sizeof(tv.tv_usec));
+ l -= sizeof(tv.tv_usec);
+ x += sizeof(tv.tv_usec);
+ }
+ if (l >= sizeof(tv.tv_sec)) {
+ memcpy(x,&tv.tv_sec,sizeof(tv.tv_sec));
+ l -= sizeof(tv.tv_sec);
+ x += sizeof(tv.tv_sec);
+ }
+ if (l >= sizeof(pid)) {
+ memcpy(x,&pid,sizeof(pid));
+ l -= sizeof(pid);
+ x += sizeof(pid);
+ }
+ /* Finally xor it with rand() output, that was already seeded with
+ * time() at startup. */
+ for (j = 0; j < len; j++)
+ p[j] ^= rand();
+ }
+ /* Turn it into hex digits taking just 4 bits out of 8 for every byte. */
+ for (j = 0; j < len; j++)
+ p[j] = charset[p[j] & 0x0F];
+ fclose(fp);
+}
+
#ifdef UTIL_TEST_MAIN
#include <assert.h>

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