我正在尝试修改原始Michael Kerrisk 的AF_UNIX SOCK_DGRAM 示例客户端/服务器程序。请单击以下两个链接（客户端、服务器）以获取更多信息。示例代码最初发表在他的书The Linux Programming Interface, 第 57 章中。我的目标是根据Kerrisk 的代码示例，用“抽象套接字”定义替换“文件套接字”定义。
不幸的是，我无法在我的客户端和服务器版本之间建立通信。当然，Kerrisk 的版本非常出色。
对我来说很明显，我在做一些根本错误的事情......但是......我不知道它是什么。
=================== 服务器============================== =
这是我的 Kerrisk 'server'代码版本：
int main(int argc, char *argv[])
{
struct sockaddr_un svaddr, claddr;
int sfd, j;
ssize_t numBytes;
socklen_t len;
char buf[BUF_SIZE];
char *abstract_server;
sfd = socket(AF_UNIX, SOCK_DGRAM, 0); /* Create server socket */
if (sfd == -1)
errExit("socket");
abstract_server = "viper_server";
/* Construct well-known address and bind server socket to it */
if (remove(abstract_server) == -1 && errno != ENOENT)
errExit("remove-%s", abstract_server);
memset(&svaddr, 0, sizeof(struct sockaddr_un));
svaddr.sun_family = AF_UNIX;
strncpy(&svaddr.sun_path[1], abstract_server, strlen(abstract_server));
if (bind(sfd, (struct sockaddr *) &svaddr,
sizeof(sa_family_t) + strlen(abstract_server) + 1) == -1)
errExit("bind");
/* Receive messages, convert to uppercase, and return to client */
for (;;) {
len = sizeof(struct sockaddr_un);
numBytes = recvfrom(sfd, buf, BUF_SIZE, 0,
(struct sockaddr *) &claddr, &len);
if (numBytes == -1)
errExit("recvfrom");
printf("Server received %ld bytes from %s\n", (long) numBytes,
claddr.sun_path);
for (j = 0; j < numBytes; j++)
buf[j] = toupper((unsigned char) buf[j]);
if (sendto(sfd, buf, numBytes, 0, (struct sockaddr *) &claddr, len) != numBytes)
fatal("sendto");
}
}
========================== 客户======================== ====
这是我的“客户端”的 Kerrisk 代码版本：
int main(int argc, char *argv[])
{
struct sockaddr_un svaddr, claddr;
int sfd, j;
size_t msgLen;
ssize_t numBytes;
char resp[BUF_SIZE];
char *abstract_client;
char *abstract_server;
if (argc < 2 || strcmp(argv[1], "--help") == 0)
usageErr("%s msg...\n", argv[0]);
/* Create client socket; bind to unique pathname (based on PID) */
sfd = socket(AF_UNIX, SOCK_DGRAM, 0);
if (sfd == -1)
errExit("socket");
abstract_client = "viper_client";
abstract_server = "viper_server";
memset(&claddr, 0, sizeof(struct sockaddr_un));
claddr.sun_family = AF_UNIX;
strncpy(&claddr.sun_path[1], abstract_client, strlen(abstract_client));
if (bind(sfd, (struct sockaddr *) &claddr,
sizeof(sa_family_t) + strlen(abstract_client) + 1) == -1)
errExit("bind");
/* Construct address of server */
memset(&svaddr, 0, sizeof(struct sockaddr_un));
svaddr.sun_family = AF_UNIX;
strncpy(&svaddr.sun_path[1], abstract_server, strlen(abstract_server));
/* Send messages to server; echo responses on stdout */
for (j = 1; j < argc; j++) {
msgLen = strlen(argv[j]); /* May be longer than BUF_SIZE */
/* code FIX */
if (sendto(sfd, argv[j], msgLen, 0, (struct sockaddr *) &svaddr,
(sizeof(sa_family_t) + strlen(abstract_server) + 1) ) != msgLen)
fatal("sendto");
/* original - non working code - replaced with the code FIX above
if (sendto(sfd, argv[j], msgLen, 0, (struct sockaddr *) &svaddr,
sizeof(struct sockaddr_un)) != msgLen)
{
fatal("sendto");
} */
numBytes = recvfrom(sfd, resp, BUF_SIZE, 0, NULL, NULL);
/* Or equivalently: numBytes = recv(sfd, resp, BUF_SIZE, 0);
or: numBytes = read(sfd, resp, BUF_SIZE); */
if (numBytes == -1)
errExit("recvfrom");
printf("Response %d: %.*s\n", j, (int) numBytes, resp);
}
remove(claddr.sun_path); /* Remove client socket pathname */
exit(EXIT_SUCCESS);
}
我如何启动测试：
> ./server &
> ./client aa bb cc
> result: ERROR: sendto
任何帮助 | 建议 | 解决方案 | RTFM 非常受欢迎
伊戈尔
PS 由于我的声誉低于 10，我只能发布 2 个链接（请参阅本文顶部的 Kerrisk 的客户端 URL、Kerrrisk 的服务器 URL）。所以，我为“如何使用抽象套接字”做了一个“剪切和粘贴” Kerrisk 的C 代码片段。它发表在他的书中，第 1176 页，清单 57-8。
int main(int argc, char *argv[])
{
int sockfd;
struct sockaddr_un addr;
char *str;
memset(&addr, 0, sizeof(struct sockaddr_un)); /* Clear address structure */
addr.sun_family = AF_UNIX; /* UNIX domain address */
/* addr.sun_path[0] has already been set to 0 by memset() */
str = "xyz"; /* Abstract name is "\0abc" */
strncpy(&addr.sun_path[1], str, strlen(str));
// In early printings of the book, the above two lines were instead:
//
// strncpy(&addr.sun_path[1], "xyz", sizeof(addr.sun_path) - 2);
// /* Abstract name is "xyz" followed by null bytes */
sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
if (sockfd == -1)
errExit("socket");
if (bind(sockfd, (struct sockaddr *) &addr,
sizeof(sa_family_t) + strlen(str) + 1) == -1)
errExit("bind");
// In early printings of the book, the final part of the bind() call
// above was instead:
// sizeof(struct sockaddr_un)) == -1)
sleep(60);
exit(EXIT_SUCCESS);
}