1 files changed, 812 insertions, 0 deletions

diff --git a/examples/redis-unstable/src/anet.c b/examples/redis-unstable/src/anet.c
new file mode 100644
index 0000000..8b7b91e
--- /dev/null
+++ b/examples/redis-unstable/src/anet.c
@@ -0,0 +1,812 @@
+/* anet.c -- Basic TCP socket stuff made a bit less boring
+ *
+ * Copyright (c) 2006-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ */
+
+#include "fmacros.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <sys/time.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <netdb.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "anet.h"
+#include "config.h"
+#include "util.h"
+
+#define UNUSED(x) (void)(x)
+
+static void anetSetError(char *err, const char *fmt, ...)
+{
+    va_list ap;
+
+    if (!err) return;
+    va_start(ap, fmt);
+    vsnprintf(err, ANET_ERR_LEN, fmt, ap);
+    va_end(ap);
+}
+
+int anetGetError(int fd) {
+    int sockerr = 0;
+    socklen_t errlen = sizeof(sockerr);
+
+    if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &sockerr, &errlen) == -1)
+        sockerr = errno;
+    return sockerr;
+}
+
+int anetSetBlock(char *err, int fd, int non_block) {
+    int flags;
+
+    /* Set the socket blocking (if non_block is zero) or non-blocking.
+     * Note that fcntl(2) for F_GETFL and F_SETFL can't be
+     * interrupted by a signal. */
+    if ((flags = fcntl(fd, F_GETFL)) == -1) {
+        anetSetError(err, "fcntl(F_GETFL): %s", strerror(errno));
+        return ANET_ERR;
+    }
+
+    /* Check if this flag has been set or unset, if so,
+     * then there is no need to call fcntl to set/unset it again. */
+    if (!!(flags & O_NONBLOCK) == !!non_block)
+        return ANET_OK;
+
+    if (non_block)
+        flags |= O_NONBLOCK;
+    else
+        flags &= ~O_NONBLOCK;
+
+    if (fcntl(fd, F_SETFL, flags) == -1) {
+        anetSetError(err, "fcntl(F_SETFL,O_NONBLOCK): %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+int anetNonBlock(char *err, int fd) {
+    return anetSetBlock(err,fd,1);
+}
+
+int anetBlock(char *err, int fd) {
+    return anetSetBlock(err,fd,0);
+}
+
+/* Enable the FD_CLOEXEC on the given fd to avoid fd leaks.
+ * This function should be invoked for fd's on specific places
+ * where fork + execve system calls are called. */
+int anetCloexec(int fd) {
+    int r;
+    int flags;
+
+    do {
+        r = fcntl(fd, F_GETFD);
+    } while (r == -1 && errno == EINTR);
+
+    if (r == -1 || (r & FD_CLOEXEC))
+        return r;
+
+    flags = r | FD_CLOEXEC;
+
+    do {
+        r = fcntl(fd, F_SETFD, flags);
+    } while (r == -1 && errno == EINTR);
+
+    return r;
+}
+
+/* Enable TCP keep-alive mechanism to detect dead peers,
+ * TCP_KEEPIDLE, TCP_KEEPINTVL and TCP_KEEPCNT will be set accordingly. */
+int anetKeepAlive(char *err, int fd, int interval)
+{
+    int enabled = 1;
+    if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &enabled, sizeof(enabled)))
+    {
+        anetSetError(err, "setsockopt SO_KEEPALIVE: %s", strerror(errno));
+        return ANET_ERR;
+    }
+
+    int idle;
+    int intvl;
+    int cnt;
+
+    /* There are platforms that are expected to support the full mechanism of TCP keep-alive,
+     * we want the compiler to emit warnings of unused variables if the preprocessor directives
+     * somehow fail, and other than those platforms, just omit these warnings if they happen.
+     */
+#if !(defined(_AIX) || defined(__APPLE__) || defined(__DragonFly__) || \
+    defined(__FreeBSD__) || defined(__illumos__) || defined(__linux__) || \
+    defined(__NetBSD__) || defined(__sun))
+    UNUSED(interval);
+    UNUSED(idle);
+    UNUSED(intvl);
+    UNUSED(cnt);
+#endif
+
+#ifdef __sun
+    /* The implementation of TCP keep-alive on Solaris/SmartOS is a bit unusual
+     * compared to other Unix-like systems.
+     * Thus, we need to specialize it on Solaris.
+     *
+     * There are two keep-alive mechanisms on Solaris:
+     * - By default, the first keep-alive probe is sent out after a TCP connection is idle for two hours.
+     * If the peer does not respond to the probe within eight minutes, the TCP connection is aborted.
+     * You can alter the interval for sending out the first probe using the socket option TCP_KEEPALIVE_THRESHOLD
+     * in milliseconds or TCP_KEEPIDLE in seconds.
+     * The system default is controlled by the TCP ndd parameter tcp_keepalive_interval. The minimum value is ten seconds.
+     * The maximum is ten days, while the default is two hours. If you receive no response to the probe,
+     * you can use the TCP_KEEPALIVE_ABORT_THRESHOLD socket option to change the time threshold for aborting a TCP connection.
+     * The option value is an unsigned integer in milliseconds. The value zero indicates that TCP should never time out and
+     * abort the connection when probing. The system default is controlled by the TCP ndd parameter tcp_keepalive_abort_interval.
+     * The default is eight minutes.
+     *
+     * - The second implementation is activated if socket option TCP_KEEPINTVL and/or TCP_KEEPCNT are set.
+     * The time between each consequent probes is set by TCP_KEEPINTVL in seconds.
+     * The minimum value is ten seconds. The maximum is ten days, while the default is two hours.
+     * The TCP connection will be aborted after certain amount of probes, which is set by TCP_KEEPCNT, without receiving response.
+     */
+
+    idle = interval;
+    if (idle < 10) idle = 10; // kernel expects at least 10 seconds
+    if (idle > 10*24*60*60) idle = 10*24*60*60; // kernel expects at most 10 days
+
+    /* `TCP_KEEPIDLE`, `TCP_KEEPINTVL`, and `TCP_KEEPCNT` were not available on Solaris
+     * until version 11.4, but let's take a chance here. */
+#if defined(TCP_KEEPIDLE) && defined(TCP_KEEPINTVL) && defined(TCP_KEEPCNT)
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle))) {
+        anetSetError(err, "setsockopt TCP_KEEPIDLE: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+
+    intvl = idle/3;
+    if (intvl < 10) intvl = 10; /* kernel expects at least 10 seconds */
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl))) {
+        anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+
+    cnt = 3;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt))) {
+        anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+#else
+    /* Fall back to the first implementation of tcp-alive mechanism for older Solaris,
+     * simulate the tcp-alive mechanism on other platforms via `TCP_KEEPALIVE_THRESHOLD` + `TCP_KEEPALIVE_ABORT_THRESHOLD`.
+     */
+    idle *= 1000; // kernel expects milliseconds
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE_THRESHOLD, &idle, sizeof(idle))) {
+        anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+
+    /* Note that the consequent probes will not be sent at equal intervals on Solaris,
+     * but will be sent using the exponential backoff algorithm. */
+    int time_to_abort = idle;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE_ABORT_THRESHOLD, &time_to_abort, sizeof(time_to_abort))) {
+        anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+#endif
+
+    return ANET_OK;
+
+#endif
+
+#ifdef TCP_KEEPIDLE
+    /* Default settings are more or less garbage, with the keepalive time
+     * set to 7200 by default on Linux and other Unix-like systems.
+     * Modify settings to make the feature actually useful. */
+
+    /* Send first probe after interval. */
+    idle = interval;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle))) {
+        anetSetError(err, "setsockopt TCP_KEEPIDLE: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+#elif defined(TCP_KEEPALIVE)
+    /* Darwin/macOS uses TCP_KEEPALIVE in place of TCP_KEEPIDLE. */
+    idle = interval;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE, &idle, sizeof(idle))) {
+        anetSetError(err, "setsockopt TCP_KEEPALIVE: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+#endif
+
+#ifdef TCP_KEEPINTVL
+    /* Send next probes after the specified interval. Note that we set the
+     * delay as interval / 3, as we send three probes before detecting
+     * an error (see the next setsockopt call). */
+    intvl = interval/3;
+    if (intvl == 0) intvl = 1;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl))) {
+        anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+#endif
+
+#ifdef TCP_KEEPCNT
+    /* Consider the socket in error state after three we send three ACK
+     * probes without getting a reply. */
+    cnt = 3;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt))) {
+        anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno));
+        return ANET_ERR;
+    }
+#endif
+
+    return ANET_OK;
+}
+
+static int anetSetTcpNoDelay(char *err, int fd, int val)
+{
+    if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val)) == -1)
+    {
+        anetSetError(err, "setsockopt TCP_NODELAY: %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+int anetEnableTcpNoDelay(char *err, int fd)
+{
+    return anetSetTcpNoDelay(err, fd, 1);
+}
+
+int anetDisableTcpNoDelay(char *err, int fd)
+{
+    return anetSetTcpNoDelay(err, fd, 0);
+}
+
+/* Set the socket send timeout (SO_SNDTIMEO socket option) to the specified
+ * number of milliseconds, or disable it if the 'ms' argument is zero. */
+int anetSendTimeout(char *err, int fd, long long ms) {
+    struct timeval tv;
+
+    tv.tv_sec = ms/1000;
+    tv.tv_usec = (ms%1000)*1000;
+    if (setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)) == -1) {
+        anetSetError(err, "setsockopt SO_SNDTIMEO: %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+/* Set the socket receive timeout (SO_RCVTIMEO socket option) to the specified
+ * number of milliseconds, or disable it if the 'ms' argument is zero. */
+int anetRecvTimeout(char *err, int fd, long long ms) {
+    struct timeval tv;
+
+    tv.tv_sec = ms/1000;
+    tv.tv_usec = (ms%1000)*1000;
+    if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) == -1) {
+        anetSetError(err, "setsockopt SO_RCVTIMEO: %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+/* Resolve the hostname "host" and set the string representation of the
+ * IP address into the buffer pointed by "ipbuf".
+ *
+ * If flags is set to ANET_IP_ONLY the function only resolves hostnames
+ * that are actually already IPv4 or IPv6 addresses. This turns the function
+ * into a validating / normalizing function.
+ *
+ * If the flag ANET_PREFER_IPV4 is set, IPv4 is preferred over IPv6.
+ * If the flag ANET_PREFER_IPV6 is set, IPv6 is preferred over IPv4.
+ * */
+int anetResolve(char *err, char *host, char *ipbuf, size_t ipbuf_len,
+                       int flags)
+{
+    struct addrinfo hints, *info;
+    int rv;
+
+    memset(&hints,0,sizeof(hints));
+    if (flags & ANET_IP_ONLY) hints.ai_flags = AI_NUMERICHOST;
+    hints.ai_family = AF_UNSPEC;
+    if (flags & ANET_PREFER_IPV4 && !(flags & ANET_PREFER_IPV6)) {
+        hints.ai_family = AF_INET;
+    } else if (flags & ANET_PREFER_IPV6 && !(flags & ANET_PREFER_IPV4)) {
+        hints.ai_family = AF_INET6;
+    }
+    hints.ai_socktype = SOCK_STREAM;  /* specify socktype to avoid dups */
+
+    rv = getaddrinfo(host, NULL, &hints, &info);
+    if (rv != 0 && hints.ai_family != AF_UNSPEC) {
+        /* Try the other IP version. */
+        hints.ai_family = (hints.ai_family == AF_INET) ? AF_INET6 : AF_INET;
+        rv = getaddrinfo(host, NULL, &hints, &info);
+    }
+    if (rv != 0) {
+        anetSetError(err, "%s", gai_strerror(rv));
+        return ANET_ERR;
+    }
+    if (info->ai_family == AF_INET) {
+        struct sockaddr_in *sa = (struct sockaddr_in *)info->ai_addr;
+        inet_ntop(AF_INET, &(sa->sin_addr), ipbuf, ipbuf_len);
+    } else {
+        struct sockaddr_in6 *sa = (struct sockaddr_in6 *)info->ai_addr;
+        inet_ntop(AF_INET6, &(sa->sin6_addr), ipbuf, ipbuf_len);
+    }
+
+    freeaddrinfo(info);
+    return ANET_OK;
+}
+
+static int anetSetReuseAddr(char *err, int fd) {
+    int yes = 1;
+    /* Make sure connection-intensive things like the redis benchmark
+     * will be able to close/open sockets a zillion of times */
+    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) == -1) {
+        anetSetError(err, "setsockopt SO_REUSEADDR: %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+static int anetCreateSocket(char *err, int domain) {
+    int s;
+    if ((s = socket(domain, SOCK_STREAM, 0)) == -1) {
+        anetSetError(err, "creating socket: %s", strerror(errno));
+        return ANET_ERR;
+    }
+
+    /* Make sure connection-intensive things like the redis benchmark
+     * will be able to close/open sockets a zillion of times */
+    if (anetSetReuseAddr(err,s) == ANET_ERR) {
+        close(s);
+        return ANET_ERR;
+    }
+    return s;
+}
+
+#define ANET_CONNECT_NONE 0
+#define ANET_CONNECT_NONBLOCK 1
+#define ANET_CONNECT_BE_BINDING 2 /* Best effort binding. */
+static int anetTcpGenericConnect(char *err, const char *addr, int port,
+                                 const char *source_addr, int flags)
+{
+    int s = ANET_ERR, rv;
+    char portstr[6];  /* strlen("65535") + 1; */
+    struct addrinfo hints, *servinfo, *bservinfo, *p, *b;
+
+    snprintf(portstr,sizeof(portstr),"%d",port);
+    memset(&hints,0,sizeof(hints));
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+
+    if ((rv = getaddrinfo(addr,portstr,&hints,&servinfo)) != 0) {
+        anetSetError(err, "%s", gai_strerror(rv));
+        return ANET_ERR;
+    }
+    for (p = servinfo; p != NULL; p = p->ai_next) {
+        /* Try to create the socket and to connect it.
+         * If we fail in the socket() call, or on connect(), we retry with
+         * the next entry in servinfo. */
+        if ((s = socket(p->ai_family,p->ai_socktype,p->ai_protocol)) == -1)
+            continue;
+        if (anetSetReuseAddr(err,s) == ANET_ERR) goto error;
+        if (flags & ANET_CONNECT_NONBLOCK && anetNonBlock(err,s) != ANET_OK)
+            goto error;
+        if (source_addr) {
+            int bound = 0;
+            /* Using getaddrinfo saves us from self-determining IPv4 vs IPv6 */
+            if ((rv = getaddrinfo(source_addr, NULL, &hints, &bservinfo)) != 0)
+            {
+                anetSetError(err, "%s", gai_strerror(rv));
+                goto error;
+            }
+            for (b = bservinfo; b != NULL; b = b->ai_next) {
+                if (bind(s,b->ai_addr,b->ai_addrlen) != -1) {
+                    bound = 1;
+                    break;
+                }
+            }
+            freeaddrinfo(bservinfo);
+            if (!bound) {
+                anetSetError(err, "bind: %s", strerror(errno));
+                goto error;
+            }
+        }
+        if (connect(s,p->ai_addr,p->ai_addrlen) == -1) {
+            /* If the socket is non-blocking, it is ok for connect() to
+             * return an EINPROGRESS error here. */
+            if (errno == EINPROGRESS && flags & ANET_CONNECT_NONBLOCK)
+                goto end;
+            close(s);
+            s = ANET_ERR;
+            continue;
+        }
+
+        /* If we ended an iteration of the for loop without errors, we
+         * have a connected socket. Let's return to the caller. */
+        goto end;
+    }
+    if (p == NULL)
+        anetSetError(err, "creating socket: %s", strerror(errno));
+
+error:
+    if (s != ANET_ERR) {
+        close(s);
+        s = ANET_ERR;
+    }
+
+end:
+    freeaddrinfo(servinfo);
+
+    /* Handle best effort binding: if a binding address was used, but it is
+     * not possible to create a socket, try again without a binding address. */
+    if (s == ANET_ERR && source_addr && (flags & ANET_CONNECT_BE_BINDING)) {
+        return anetTcpGenericConnect(err,addr,port,NULL,flags);
+    } else {
+        return s;
+    }
+}
+
+int anetTcpNonBlockConnect(char *err, const char *addr, int port)
+{
+    return anetTcpGenericConnect(err,addr,port,NULL,ANET_CONNECT_NONBLOCK);
+}
+
+int anetTcpNonBlockBestEffortBindConnect(char *err, const char *addr, int port,
+                                         const char *source_addr)
+{
+    return anetTcpGenericConnect(err,addr,port,source_addr,
+            ANET_CONNECT_NONBLOCK|ANET_CONNECT_BE_BINDING);
+}
+
+int anetUnixGenericConnect(char *err, const char *path, int flags)
+{
+    int s;
+    struct sockaddr_un sa;
+
+    if ((s = anetCreateSocket(err,AF_LOCAL)) == ANET_ERR)
+        return ANET_ERR;
+
+    sa.sun_family = AF_LOCAL;
+    redis_strlcpy(sa.sun_path,path,sizeof(sa.sun_path));
+    if (flags & ANET_CONNECT_NONBLOCK) {
+        if (anetNonBlock(err,s) != ANET_OK) {
+            close(s);
+            return ANET_ERR;
+        }
+    }
+    if (connect(s,(struct sockaddr*)&sa,sizeof(sa)) == -1) {
+        if (errno == EINPROGRESS &&
+            flags & ANET_CONNECT_NONBLOCK)
+            return s;
+
+        anetSetError(err, "connect: %s", strerror(errno));
+        close(s);
+        return ANET_ERR;
+    }
+    return s;
+}
+
+static int anetListen(char *err, int s, struct sockaddr *sa, socklen_t len, int backlog, mode_t perm) {
+    if (bind(s,sa,len) == -1) {
+        anetSetError(err, "bind: %s", strerror(errno));
+        close(s);
+        return ANET_ERR;
+    }
+
+    if (sa->sa_family == AF_LOCAL && perm)
+        chmod(((struct sockaddr_un *) sa)->sun_path, perm);
+
+    if (listen(s, backlog) == -1) {
+        anetSetError(err, "listen: %s", strerror(errno));
+        close(s);
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+static int anetV6Only(char *err, int s) {
+    int yes = 1;
+    if (setsockopt(s,IPPROTO_IPV6,IPV6_V6ONLY,&yes,sizeof(yes)) == -1) {
+        anetSetError(err, "setsockopt: %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+}
+
+static int _anetTcpServer(char *err, int port, char *bindaddr, int af, int backlog)
+{
+    int s = -1, rv;
+    char _port[6];  /* strlen("65535") */
+    struct addrinfo hints, *servinfo, *p;
+
+    snprintf(_port,6,"%d",port);
+    memset(&hints,0,sizeof(hints));
+    hints.ai_family = af;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_PASSIVE;    /* No effect if bindaddr != NULL */
+    if (bindaddr && !strcmp("*", bindaddr))
+        bindaddr = NULL;
+    if (af == AF_INET6 && bindaddr && !strcmp("::*", bindaddr))
+        bindaddr = NULL;
+
+    if ((rv = getaddrinfo(bindaddr,_port,&hints,&servinfo)) != 0) {
+        anetSetError(err, "%s", gai_strerror(rv));
+        return ANET_ERR;
+    }
+    for (p = servinfo; p != NULL; p = p->ai_next) {
+        if ((s = socket(p->ai_family,p->ai_socktype,p->ai_protocol)) == -1)
+            continue;
+
+        if (af == AF_INET6 && anetV6Only(err,s) == ANET_ERR) goto error;
+        if (anetSetReuseAddr(err,s) == ANET_ERR) goto error;
+        if (anetListen(err,s,p->ai_addr,p->ai_addrlen,backlog,0) == ANET_ERR) s = ANET_ERR;
+        goto end;
+    }
+    if (p == NULL) {
+        anetSetError(err, "unable to bind socket, errno: %d", errno);
+        goto error;
+    }
+
+error:
+    if (s != -1) close(s);
+    s = ANET_ERR;
+end:
+    freeaddrinfo(servinfo);
+    return s;
+}
+
+int anetTcpServer(char *err, int port, char *bindaddr, int backlog)
+{
+    return _anetTcpServer(err, port, bindaddr, AF_INET, backlog);
+}
+
+int anetTcp6Server(char *err, int port, char *bindaddr, int backlog)
+{
+    return _anetTcpServer(err, port, bindaddr, AF_INET6, backlog);
+}
+
+int anetUnixServer(char *err, char *path, mode_t perm, int backlog)
+{
+    int s;
+    struct sockaddr_un sa;
+
+    if (strlen(path) > sizeof(sa.sun_path)-1) {
+        anetSetError(err,"unix socket path too long (%zu), must be under %zu", strlen(path), sizeof(sa.sun_path));
+        return ANET_ERR;
+    }
+    if ((s = anetCreateSocket(err,AF_LOCAL)) == ANET_ERR)
+        return ANET_ERR;
+
+    memset(&sa,0,sizeof(sa));
+    sa.sun_family = AF_LOCAL;
+    redis_strlcpy(sa.sun_path,path,sizeof(sa.sun_path));
+    if (anetListen(err,s,(struct sockaddr*)&sa,sizeof(sa),backlog,perm) == ANET_ERR)
+        return ANET_ERR;
+    return s;
+}
+
+/* Accept a connection and also make sure the socket is non-blocking, and CLOEXEC.
+ * returns the new socket FD, or -1 on error. */
+static int anetGenericAccept(char *err, int s, struct sockaddr *sa, socklen_t *len) {
+    int fd;
+    do {
+        /* Use the accept4() call on linux to simultaneously accept and
+         * set a socket as non-blocking. */
+#ifdef HAVE_ACCEPT4
+        fd = accept4(s, sa, len,  SOCK_NONBLOCK | SOCK_CLOEXEC);
+#else
+        fd = accept(s,sa,len);
+#endif
+    } while(fd == -1 && errno == EINTR);
+    if (fd == -1) {
+        anetSetError(err, "accept: %s", strerror(errno));
+        return ANET_ERR;
+    }
+#ifndef HAVE_ACCEPT4
+    if (anetCloexec(fd) == -1) {
+        anetSetError(err, "anetCloexec: %s", strerror(errno));
+        close(fd);
+        return ANET_ERR;
+    }
+    if (anetNonBlock(err, fd) != ANET_OK) {
+        close(fd);
+        return ANET_ERR;
+    }
+#endif
+    return fd;
+}
+
+/* Accept a connection and also make sure the socket is non-blocking, and CLOEXEC.
+ * returns the new socket FD, or -1 on error. */
+int anetTcpAccept(char *err, int serversock, char *ip, size_t ip_len, int *port) {
+    int fd;
+    struct sockaddr_storage sa;
+    socklen_t salen = sizeof(sa);
+    if ((fd = anetGenericAccept(err,serversock,(struct sockaddr*)&sa,&salen)) == ANET_ERR)
+        return ANET_ERR;
+
+    if (sa.ss_family == AF_INET) {
+        struct sockaddr_in *s = (struct sockaddr_in *)&sa;
+        if (ip) inet_ntop(AF_INET,(void*)&(s->sin_addr),ip,ip_len);
+        if (port) *port = ntohs(s->sin_port);
+    } else {
+        struct sockaddr_in6 *s = (struct sockaddr_in6 *)&sa;
+        if (ip) inet_ntop(AF_INET6,(void*)&(s->sin6_addr),ip,ip_len);
+        if (port) *port = ntohs(s->sin6_port);
+    }
+    return fd;
+}
+
+/* Accept a connection and also make sure the socket is non-blocking, and CLOEXEC.
+ * returns the new socket FD, or -1 on error. */
+int anetUnixAccept(char *err, int s) {
+    int fd;
+    struct sockaddr_un sa;
+    socklen_t salen = sizeof(sa);
+    if ((fd = anetGenericAccept(err,s,(struct sockaddr*)&sa,&salen)) == ANET_ERR)
+        return ANET_ERR;
+
+    return fd;
+}
+
+int anetFdToString(int fd, char *ip, size_t ip_len, int *port, int remote) {
+    struct sockaddr_storage sa;
+    socklen_t salen = sizeof(sa);
+
+    if (remote) {
+        if (getpeername(fd, (struct sockaddr *)&sa, &salen) == -1) goto error;
+    } else {
+        if (getsockname(fd, (struct sockaddr *)&sa, &salen) == -1) goto error;
+    }
+
+    if (sa.ss_family == AF_INET) {
+        struct sockaddr_in *s = (struct sockaddr_in *)&sa;
+        if (ip) {
+            if (inet_ntop(AF_INET,(void*)&(s->sin_addr),ip,ip_len) == NULL)
+                goto error;
+        }
+        if (port) *port = ntohs(s->sin_port);
+    } else if (sa.ss_family == AF_INET6) {
+        struct sockaddr_in6 *s = (struct sockaddr_in6 *)&sa;
+        if (ip) {
+            if (inet_ntop(AF_INET6,(void*)&(s->sin6_addr),ip,ip_len) == NULL)
+                goto error;
+        }
+        if (port) *port = ntohs(s->sin6_port);
+    } else if (sa.ss_family == AF_UNIX) {
+        if (ip) {
+            int res = snprintf(ip, ip_len, "/unixsocket");
+            if (res < 0 || (unsigned int) res >= ip_len) goto error;
+        }
+        if (port) *port = 0;
+    } else {
+        goto error;
+    }
+    return 0;
+
+error:
+    if (ip) {
+        if (ip_len >= 2) {
+            ip[0] = '?';
+            ip[1] = '\0';
+        } else if (ip_len == 1) {
+            ip[0] = '\0';
+        }
+    }
+    if (port) *port = 0;
+    return -1;
+}
+
+/* Create a pipe buffer with given flags for read end and write end.
+ * Note that it supports the file flags defined by pipe2() and fcntl(F_SETFL),
+ * and one of the use cases is O_CLOEXEC|O_NONBLOCK. */
+int anetPipe(int fds[2], int read_flags, int write_flags) {
+    int pipe_flags = 0;
+#if defined(__linux__) || defined(__FreeBSD__)
+    /* When possible, try to leverage pipe2() to apply flags that are common to both ends.
+     * There is no harm to set O_CLOEXEC to prevent fd leaks. */
+    pipe_flags = O_CLOEXEC | (read_flags & write_flags);
+    if (pipe2(fds, pipe_flags)) {
+        /* Fail on real failures, and fallback to simple pipe if pipe2 is unsupported. */
+        if (errno != ENOSYS && errno != EINVAL)
+            return -1;
+        pipe_flags = 0;
+    } else {
+        /* If the flags on both ends are identical, no need to do anything else. */
+        if ((O_CLOEXEC | read_flags) == (O_CLOEXEC | write_flags))
+            return 0;
+        /* Clear the flags which have already been set using pipe2. */
+        read_flags &= ~pipe_flags;
+        write_flags &= ~pipe_flags;
+    }
+#endif
+
+    /* When we reach here with pipe_flags of 0, it means pipe2 failed (or was not attempted),
+     * so we try to use pipe. Otherwise, we skip and proceed to set specific flags below. */
+    if (pipe_flags == 0 && pipe(fds))
+        return -1;
+
+    /* File descriptor flags.
+     * Currently, only one such flag is defined: FD_CLOEXEC, the close-on-exec flag. */
+    if (read_flags & O_CLOEXEC)
+        if (fcntl(fds[0], F_SETFD, FD_CLOEXEC))
+            goto error;
+    if (write_flags & O_CLOEXEC)
+        if (fcntl(fds[1], F_SETFD, FD_CLOEXEC))
+            goto error;
+
+    /* File status flags after clearing the file descriptor flag O_CLOEXEC. */
+    read_flags &= ~O_CLOEXEC;
+    if (read_flags)
+        if (fcntl(fds[0], F_SETFL, read_flags))
+            goto error;
+    write_flags &= ~O_CLOEXEC;
+    if (write_flags)
+        if (fcntl(fds[1], F_SETFL, write_flags))
+            goto error;
+
+    return 0;
+
+error:
+    close(fds[0]);
+    close(fds[1]);
+    return -1;
+}
+
+int anetSetSockMarkId(char *err, int fd, uint32_t id) {
+#ifdef HAVE_SOCKOPTMARKID
+    if (setsockopt(fd, SOL_SOCKET, SOCKOPTMARKID, (void *)&id, sizeof(id)) == -1) {
+        anetSetError(err, "setsockopt: %s", strerror(errno));
+        return ANET_ERR;
+    }
+    return ANET_OK;
+#else
+    UNUSED(fd);
+    UNUSED(id);
+    anetSetError(err,"anetSetSockMarkid unsupported on this platform");
+    return ANET_OK;
+#endif
+}
+
+int anetIsFifo(char *filepath) {
+    struct stat sb;
+    if (stat(filepath, &sb) == -1) return 0;
+    return S_ISFIFO(sb.st_mode);
+}
+
+/* This function must be called after accept4() fails. It returns 1 if 'err'
+ * indicates accepted connection faced an error, and it's okay to continue
+ * accepting next connection by calling accept4() again. Other errors either
+ * indicate programming errors, e.g. calling accept() on a closed fd or indicate
+ * a resource limit has been reached, e.g. -EMFILE, open fd limit has been
+ * reached. In the latter case, caller might wait until resources are available.
+ * See accept4() documentation for details. */
+int anetAcceptFailureNeedsRetry(int err) {
+    if (err == ECONNABORTED)
+        return 1;
+
+#if defined(__linux__)
+    /* For details, see 'Error Handling' section on
+     * https://man7.org/linux/man-pages/man2/accept.2.html */
+    if (err == ENETDOWN || err == EPROTO || err == ENOPROTOOPT ||
+        err == EHOSTDOWN || err == ENONET || err == EHOSTUNREACH ||
+        err == EOPNOTSUPP || err == ENETUNREACH)
+    {
+        return 1;
+    }
+#endif
+    return 0;
+}