Hi,
> Subject: [Qemu-devel] [PATCH v3 1/2] contrib: add ivshmem client and server
>
> When using ivshmem devices, notifications between guests can be sent as
> interrupts using a ivshmem-server (typical use described in documentation).
> The client is provided as a debug tool.
>
> Signed-off-by: Olivier Matz <olivier.matz@xxxxxxxxx>
> Signed-off-by: David Marchand <david.marchand@xxxxxxxxx>
> ---
> contrib/ivshmem-client/Makefile | 29 +++
> contrib/ivshmem-client/ivshmem-client.c | 418
> ++++++++++++++++++++++++++++++
> contrib/ivshmem-client/ivshmem-client.h | 238 ++++++++++++++++++
> contrib/ivshmem-client/main.c | 246 ++++++++++++++++++
> contrib/ivshmem-server/Makefile | 29 +++
> contrib/ivshmem-server/ivshmem-server.c | 420
> +++++++++++++++++++++++++++++++
> contrib/ivshmem-server/ivshmem-server.h | 185 ++++++++++++++
> contrib/ivshmem-server/main.c | 296
> ++++++++++++++++++++++
> qemu-doc.texi | 10 +-
> 9 files changed, 1868 insertions(+), 3 deletions(-)
> create mode 100644 contrib/ivshmem-client/Makefile
> create mode 100644 contrib/ivshmem-client/ivshmem-client.c
> create mode 100644 contrib/ivshmem-client/ivshmem-client.h
> create mode 100644 contrib/ivshmem-client/main.c
> create mode 100644 contrib/ivshmem-server/Makefile
> create mode 100644 contrib/ivshmem-server/ivshmem-server.c
> create mode 100644 contrib/ivshmem-server/ivshmem-server.h
> create mode 100644 contrib/ivshmem-server/main.c
>
> diff --git a/contrib/ivshmem-client/Makefile b/contrib/ivshmem-client/Makefile
> new file mode 100644
> index 0000000..eee97c6
> --- /dev/null
> +++ b/contrib/ivshmem-client/Makefile
> @@ -0,0 +1,29 @@
> +# Copyright 6WIND S.A., 2014
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2 or
> +# (at your option) any later version. See the COPYING file in the
> +# top-level directory.
> +
> +S ?= $(CURDIR)
> +O ?= $(CURDIR)
> +
> +CFLAGS += -Wall -Wextra -Werror -g
> +LDFLAGS +=
> +LDLIBS += -lrt
> +
> +VPATH = $(S)
> +PROG = ivshmem-client
> +OBJS := $(O)/ivshmem-client.o
> +OBJS += $(O)/main.o
> +
> +$(O)/%.o: %.c
> + $(CC) $(CFLAGS) -o $@ -c $<
> +
> +$(O)/$(PROG): $(OBJS)
> + $(CC) $(LDFLAGS) -o $@ $^ $(LDLIBS)
> +
> +.PHONY: all
> +all: $(O)/$(PROG)
> +
> +clean:
> + rm -f $(OBJS) $(O)/$(PROG)
> diff --git a/contrib/ivshmem-client/ivshmem-client.c
> b/contrib/ivshmem-client/ivshmem-client.c
> new file mode 100644
> index 0000000..2166b64
> --- /dev/null
> +++ b/contrib/ivshmem-client/ivshmem-client.c
> @@ -0,0 +1,418 @@
> +/*
> + * Copyright 6WIND S.A., 2014
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * (at your option) any later version. See the COPYING file in the
> + * top-level directory.
> + */
> +
> +#include <stdio.h>
> +#include <stdint.h>
> +#include <stdlib.h>
> +#include <errno.h>
> +#include <string.h>
> +#include <signal.h>
> +#include <unistd.h>
> +#include <inttypes.h>
> +#include <sys/queue.h>
> +
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +#include <sys/un.h>
> +
> +#include "ivshmem-client.h"
> +
> +/* log a message on stdout if verbose=1 */
> +#define debug_log(client, fmt, ...) do { \
> + if ((client)->verbose) { \
> + printf(fmt, ## __VA_ARGS__); \
> + } \
> + } while (0)
> +
> +/* read message from the unix socket */
> +static int
> +read_one_msg(struct ivshmem_client *client, long *index, int *fd)
> +{
> + int ret;
> + struct msghdr msg;
> + struct iovec iov[1];
> + union {
> + struct cmsghdr cmsg;
> + char control[CMSG_SPACE(sizeof(int))];
> + } msg_control;
> + struct cmsghdr *cmsg;
> +
> + iov[0].iov_base = index;
> + iov[0].iov_len = sizeof(*index);
> +
> + memset(&msg, 0, sizeof(msg));
> + msg.msg_iov = iov;
> + msg.msg_iovlen = 1;
> + msg.msg_control = &msg_control;
> + msg.msg_controllen = sizeof(msg_control);
> +
> + ret = recvmsg(client->sock_fd, &msg, 0);
> + if (ret < 0) {
> + debug_log(client, "cannot read message: %s\n", strerror(errno));
> + return -1;
> + }
> + if (ret == 0) {
> + debug_log(client, "lost connection to server\n");
> + return -1;
> + }
> +
> + *fd = -1;
> +
> + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg =
> CMSG_NXTHDR(&msg, cmsg)) {
> +
> + if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
> + cmsg->cmsg_level != SOL_SOCKET ||
> + cmsg->cmsg_type != SCM_RIGHTS) {
> + continue;
> + }
> +
> + memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd));
> + }
> +
> + return 0;
> +}
> +
> +/* free a peer when the server advertise a disconnection or when the
> + * client is freed */
> +static void
> +free_peer(struct ivshmem_client *client, struct ivshmem_client_peer *peer)
> +{
> + unsigned vector;
> +
> + TAILQ_REMOVE(&client->peer_list, peer, next);
> + for (vector = 0; vector < peer->vectors_count; vector++) {
> + close(peer->vectors[vector]);
> + }
> +
> + free(peer);
> +}
> +
> +/* handle message coming from server (new peer, new vectors) */
> +static int
> +handle_server_msg(struct ivshmem_client *client)
> +{
> + struct ivshmem_client_peer *peer;
> + long peer_id;
> + int ret, fd;
> +
> + ret = read_one_msg(client, &peer_id, &fd);
> + if (ret < 0) {
> + return -1;
> + }
> +
> + /* can return a peer or the local client */
> + peer = ivshmem_client_search_peer(client, peer_id);
> +
> + /* delete peer */
> + if (fd == -1) {
> +
Maybe the above check should be moved before getting the peer.
And the next check peer is extra.
> + if (peer == NULL || peer == &client->local) {
> + debug_log(client, "receive delete for invalid peer %ld",
Missing '\n' ?
> peer_id);
> + return -1;
> + }
> +
> + debug_log(client, "delete peer id = %ld\n", peer_id);
> + free_peer(client, peer);
> + return 0;
> + }
> +
> + /* new peer */
> + if (peer == NULL) {
> + peer = malloc(sizeof(*peer));
g_malloc0 ?.
> + if (peer == NULL) {
> + debug_log(client, "cannot allocate new peer\n");
> + return -1;
> + }
> + memset(peer, 0, sizeof(*peer));
> + peer->id = peer_id;
> + peer->vectors_count = 0;
> + TAILQ_INSERT_TAIL(&client->peer_list, peer, next);
> + debug_log(client, "new peer id = %ld\n", peer_id);
> + }
> +
> + /* new vector */
> + debug_log(client, " new vector %d (fd=%d) for peer id %ld\n",
> + peer->vectors_count, fd, peer->id);
> + peer->vectors[peer->vectors_count] = fd;
> + peer->vectors_count++;
> +
> + return 0;
> +}
> +
> +/* init a new ivshmem client */
> +int
> +ivshmem_client_init(struct ivshmem_client *client, const char
> *unix_sock_path,
> + ivshmem_client_notif_cb_t notif_cb, void *notif_arg,
> + int verbose)
> +{
> + unsigned i;
> +
> + memset(client, 0, sizeof(*client));
> +
> + snprintf(client->unix_sock_path, sizeof(client->unix_sock_path),
> + "%s", unix_sock_path);
> +
> + for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
> + client->local.vectors[i] = -1;
> + }
> +
> + TAILQ_INIT(&client->peer_list);
> + client->local.id = -1;
> +
> + client->notif_cb = notif_cb;
> + client->notif_arg = notif_arg;
> + client->verbose = verbose;
Missing client->sock_fd = -1; ?
> +
> + return 0;
> +}
> +
> +/* create and connect to the unix socket */
> +int
> +ivshmem_client_connect(struct ivshmem_client *client)
> +{
> + struct sockaddr_un sun;
> + int fd;
> + long tmp;
> +
> + debug_log(client, "connect to client %s\n", client->unix_sock_path);
> +
> + client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
> + if (client->sock_fd < 0) {
> + debug_log(client, "cannot create socket: %s\n", strerror(errno));
> + return -1;
> + }
> +
> + sun.sun_family = AF_UNIX;
> + snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
> client->unix_sock_path);
> + if (connect(client->sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
> + debug_log(client, "cannot connect to %s: %s\n", sun.sun_path,
> + strerror(errno));
> + close(client->sock_fd);
> + client->sock_fd = -1;
> + return -1;
> + }
> +
> + /* first, we expect our index + a fd == -1 */
> + if (read_one_msg(client, &client->local.id, &fd) < 0 ||
> + client->local.id < 0 || fd != -1) {
Why not fd < 0 ?
> + debug_log(client, "cannot read from server\n");
> + close(client->sock_fd);
> + client->sock_fd = -1;
> + return -1;
> + }
> + debug_log(client, "our_id=%ld\n", client->local.id);
> +
> + /* now, we expect shared mem fd + a -1 index, note that shm fd
> + * is not used */
> + if (read_one_msg(client, &tmp, &fd) < 0 ||
> + tmp != -1 || fd < 0) {
> + debug_log(client, "cannot read from server (2)\n");
> + close(client->sock_fd);
> + client->sock_fd = -1;
> + return -1;
I think the error logic handle can move the end of this function, reducing
duplicated code. Something like this:
goto err;
}
err:
debug_log(client, "cannot read from server (2)\n");
close(client->sock_fd);
client->sock_fd = -1;
return -1;
> + }
> + debug_log(client, "shm_fd=%d\n", fd);
> +
> + return 0;
> +}
> +
> +/* close connection to the server, and free all peer structures */
> +void
> +ivshmem_client_close(struct ivshmem_client *client)
> +{
> + struct ivshmem_client_peer *peer;
> + unsigned i;
> +
> + debug_log(client, "close client\n");
> +
> + while ((peer = TAILQ_FIRST(&client->peer_list)) != NULL) {
> + free_peer(client, peer);
> + }
> +
> + close(client->sock_fd);
> + client->sock_fd = -1;
> + client->local.id = -1;
> + for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
> + client->local.vectors[i] = -1;
> + }
> +}
> +
> +/* get the fd_set according to the unix socket and peer list */
> +void
> +ivshmem_client_get_fds(const struct ivshmem_client *client, fd_set *fds,
> + int *maxfd)
> +{
> + int fd;
> + unsigned vector;
> +
> + FD_SET(client->sock_fd, fds);
> + if (client->sock_fd >= *maxfd) {
> + *maxfd = client->sock_fd + 1;
> + }
> +
> + for (vector = 0; vector < client->local.vectors_count; vector++) {
> + fd = client->local.vectors[vector];
> + FD_SET(fd, fds);
> + if (fd >= *maxfd) {
> + *maxfd = fd + 1;
> + }
> + }
> +}
> +
> +/* handle events from eventfd: just print a message on notification */
> +static int
> +handle_event(struct ivshmem_client *client, const fd_set *cur, int maxfd)
> +{
> + struct ivshmem_client_peer *peer;
> + uint64_t kick;
> + unsigned i;
> + int ret;
> +
> + peer = &client->local;
> +
> + for (i = 0; i < peer->vectors_count; i++) {
> + if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) {
> + continue;
> + }
> +
> + ret = read(peer->vectors[i], &kick, sizeof(kick));
> + if (ret < 0) {
> + return ret;
> + }
> + if (ret != sizeof(kick)) {
> + debug_log(client, "invalid read size = %d\n", ret);
> + errno = EINVAL;
> + return -1;
> + }
> + debug_log(client, "received event on fd %d vector %d: %ld\n",
> + peer->vectors[i], i, kick);
> + if (client->notif_cb != NULL) {
> + client->notif_cb(client, peer, i, client->notif_arg);
> + }
> + }
> +
> + return 0;
> +}
> +
> +/* read and handle new messages on the given fd_set */
> +int
> +ivshmem_client_handle_fds(struct ivshmem_client *client, fd_set *fds, int
> maxfd)
> +{
> + if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) &&
> + handle_server_msg(client) < 0 && errno != EINTR) {
> + debug_log(client, "handle_server_msg() failed\n");
> + return -1;
> + } else if (handle_event(client, fds, maxfd) < 0 && errno != EINTR) {
> + debug_log(client, "handle_event() failed\n");
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +/* send a notification on a vector of a peer */
> +int
> +ivshmem_client_notify(const struct ivshmem_client *client,
> + const struct ivshmem_client_peer *peer, unsigned
> vector)
> +{
> + uint64_t kick;
> + int fd;
> +
> + if (vector > peer->vectors_count) {
Maybe if (vector >= peer->vectors_count) , otherwise the
peer->vectors[] array bounds.
> + debug_log(client, "invalid vector %u on peer %ld\n", vector,
> peer->id);
> + return -1;
> + }
> + fd = peer->vectors[vector];
Or fd = peer->vectors[vector - 1]; ?
> + debug_log(client, "notify peer %ld on vector %d, fd %d\n", peer->id,
> vector,
> + fd);
> +
> + kick = 1;
> + if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) {
> + fprintf(stderr, "could not write to %d: %s\n", peer->vectors[vector],
> + strerror(errno));
Why not debug_log() at this here?
> + return -1;
> + }
> + return 0;
> +}
> +
> +/* send a notification to all vectors of a peer */
> +int
> +ivshmem_client_notify_all_vects(const struct ivshmem_client *client,
> + const struct ivshmem_client_peer
> *peer)
> +{
> + unsigned vector;
> + int ret = 0;
> +
> + for (vector = 0; vector < peer->vectors_count; vector++) {
> + if (ivshmem_client_notify(client, peer, vector) < 0) {
> + ret = -1;
The ret's value will be covered when multi clients failed. Do we need
store the failed status for server?.
> + }
> + }
> +
> + return ret;
> +}
> +
> +/* send a notification to all peers */
> +int
> +ivshmem_client_notify_broadcast(const struct ivshmem_client *client)
> +{
> + struct ivshmem_client_peer *peer;
> + int ret = 0;
> +
> + TAILQ_FOREACH(peer, &client->peer_list, next) {
> + if (ivshmem_client_notify_all_vects(client, peer) < 0) {
> + ret = -1;
> + }
> + }
> +
> + return ret;
> +}
> +
> +/* lookup peer from its id */
> +struct ivshmem_client_peer *
> +ivshmem_client_search_peer(struct ivshmem_client *client, long peer_id)
> +{
> + struct ivshmem_client_peer *peer;
> +
> + if (peer_id == client->local.id) {
> + return &client->local;
> + }
> +
> + TAILQ_FOREACH(peer, &client->peer_list, next) {
> + if (peer->id == peer_id) {
> + return peer;
> + }
> + }
> + return NULL;
> +}
> +
> +/* dump our info, the list of peers their vectors on stdout */
> +void
> +ivshmem_client_dump(const struct ivshmem_client *client)
> +{
> + const struct ivshmem_client_peer *peer;
> + unsigned vector;
> +
> + /* dump local infos */
> + peer = &client->local;
> + printf("our_id = %ld\n", peer->id);
> + for (vector = 0; vector < peer->vectors_count; vector++) {
> + printf(" vector %d is enabled (fd=%d)\n", vector,
> + peer->vectors[vector]);
> + }
> +
> + /* dump peers */
> + TAILQ_FOREACH(peer, &client->peer_list, next) {
> + printf("peer_id = %ld\n", peer->id);
> +
> + for (vector = 0; vector < peer->vectors_count; vector++) {
> + printf(" vector %d is enabled (fd=%d)\n", vector,
> + peer->vectors[vector]);
> + }
> + }
> +}
To be continued...
Best regards,
-Gonglei
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