WIP: Prevent race condition around strerror which is not thread safe

src/Makefile

@@ -206,11 +206,13 @@ endif
 
 REDIS_SERVER_NAME=redis-server
 REDIS_SENTINEL_NAME=redis-sentinel
-REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o redis-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o lolwut6.o acl.o gopher.o tracking.o connection.o tls.o sha256.o timeout.o
+
+REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o redis_err.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o redis-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o lolwut6.o acl.o gopher.o tracking.o connection.o tls.o sha256.o timeout.o
 REDIS_CLI_NAME=redis-cli
-REDIS_CLI_OBJ=anet.o adlist.o dict.o redis-cli.o zmalloc.o release.o ae.o crc64.o siphash.o crc16.o
+REDIS_CLI_OBJ=anet.o adlist.o dict.o redis-cli.o zmalloc.o redis_err.o release.o ae.o crc64.o siphash.o crc16.o
 REDIS_BENCHMARK_NAME=redis-benchmark
-REDIS_BENCHMARK_OBJ=ae.o anet.o redis-benchmark.o adlist.o dict.o zmalloc.o siphash.o
+REDIS_BENCHMARK_OBJ=ae.o anet.o redis-benchmark.o adlist.o dict.o zmalloc.o redis_err.o siphash.o
+
 REDIS_CHECK_RDB_NAME=redis-check-rdb
 REDIS_CHECK_AOF_NAME=redis-check-aof
 

src/config.c

@@ -30,6 +30,7 @@
 
 #include "server.h"
 #include "cluster.h"
+#include "redis_err.h"
 
 #include <fcntl.h>
 #include <sys/stat.h>
@@ -550,7 +551,7 @@ void loadServerConfig(char *filename, char *options) {
         } else {
             if ((fp = fopen(filename,"r")) == NULL) {
                 serverLog(LL_WARNING,
-                    "Fatal error, can't open config file '%s'", filename);
+                    "Fatal error, can't open config file '%s', %s", filename, redisError(errno));
                 exit(1);
             }
         }

src/redis_err.c

@@ -0,0 +1,67 @@
+/*
+ * strerror is not thread safe
+ * why oh why should I complain
+ * when strerror_r & _l behave differently
+ * Across the Unix domain
+ *
+ * after distinguishing between the two
+ * And allocating error strings all over
+ * You have ugly Marcos
+ * (and are still not async signal safe)
+ *
+ * Allocate a static array containing all possible error strings
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "redis_err.h"
+#include "zmalloc.h"
+
+const char **ERROR_ARRAY;
+/* sys_nerr  is considered internal impl. detail, and isn't available on all OSes */
+const unsigned int MAX_ERR = 256;
+const char *UNKNOWN_STRING = "Unknown error";
+
+/*
+ * Initialize the error array
+ */
+int initErrorStrings(){
+    ERROR_ARRAY = zmalloc(sizeof(char*)*(MAX_ERR));
+
+    unsigned int n = 0;
+    char *err;
+
+    for (; n < MAX_ERR; n++) {
+        err = strerror(n);
+        if (err == NULL
+            || strncasecmp(err, UNKNOWN_STRING, 13) == 0)
+        {
+            ERROR_ARRAY[n] = UNKNOWN_STRING;
+            continue;
+        }
+        ERROR_ARRAY[n] = zstrdup(err);
+    }
+    return 0;
+}
+
+
+const char *redisError(unsigned int err) {
+    if (err > MAX_ERR) {
+        perror("Requested out of bounds error string");
+        return UNKNOWN_STRING;
+    }
+    return ERROR_ARRAY[err];
+}
+
+
+void freeErrorStrings() {
+    unsigned int n = 0;
+    for (;n < MAX_ERR; n++) {
+        if (ERROR_ARRAY[n] != UNKNOWN_STRING) {
+            zfree((void *)ERROR_ARRAY[n]);
+        }
+    }
+
+}

src/redis_err.h

@@ -0,0 +1,13 @@
+//
+// Created by uri on 6/7/19.
+//
+
+#ifndef REDIS_REDIS_ERR_H
+#define REDIS_REDIS_ERR_H
+
+
+int initErrorStrings ();
+const char *redisError(unsigned int err);
+void freeErrorStrings();
+
+#endif //REDIS_REDIS_ERR_H

src/server.c

@@ -33,6 +33,7 @@
 #include "bio.h"
 #include "latency.h"
 #include "atomicvar.h"
+#include "redis_err.h"
 
 #include <time.h>
 #include <signal.h>
@@ -1767,7 +1768,7 @@ void checkChildrenDone(void) {
         if (pid == -1) {
             serverLog(LL_WARNING,"wait3() returned an error: %s. "
                 "rdb_child_pid = %d, aof_child_pid = %d, module_child_pid = %d",
-                strerror(errno),
+                redisError(errno),
                 (int) server.rdb_child_pid,
                 (int) server.aof_child_pid,
                 (int) server.module_child_pid);
@@ -2843,7 +2844,7 @@ void initServer(void) {
                                O_WRONLY|O_APPEND|O_CREAT,0644);
         if (server.aof_fd == -1) {
             serverLog(LL_WARNING, "Can't open the append-only file: %s",
-                strerror(errno));
+                redisError(errno));
             exit(1);
         }
     }
@@ -4773,7 +4774,7 @@ void loadDataFromDisk(void) {
                 selectDb(server.cached_master,rsi.repl_stream_db);
             }
         } else if (errno != ENOENT) {
-            serverLog(LL_WARNING,"Fatal error loading the DB: %s. Exiting.",strerror(errno));
+            serverLog(LL_WARNING,"Fatal error loading the DB: %s. Exiting.",redisError(errno));
             exit(1);
         }
     }
@@ -4902,6 +4903,7 @@ int main(int argc, char **argv) {
     setlocale(LC_COLLATE,"");
     tzset(); /* Populates 'timezone' global. */
     zmalloc_set_oom_handler(redisOutOfMemoryHandler);
+    initErrorStrings();
     srand(time(NULL)^getpid());
     gettimeofday(&tv,NULL);
 
@@ -5073,6 +5075,7 @@ int main(int argc, char **argv) {
     aeSetAfterSleepProc(server.el,afterSleep);
     aeMain(server.el);
     aeDeleteEventLoop(server.el);
+    freeErrorStrings();
     return 0;
 }