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bhyve/snapshot: use SOCK_DGRAM instead of SOCK_STREAM

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The save/restore feature uses a unix domain socket to send messages
from bhyvectl(8) to a bhyve(8) process. A datagram socket will suffice
for this.

An added benefit of using a datagram socket is simplified code. For
bhyve, the listen/accept calls are dropped; and for bhyvectl, the
connect() call is dropped.

EPRINTLN handles raw mode for bhyve(8), use it to print error messages.

Reviewed by:	jhb
Differential Revision:	https://reviews.freebsd.org/D28983
This commit is contained in:
Robert Wing 2021-03-07 15:23:29 -09:00
parent 0424d9ebeb
commit 38dfb0626f
2 changed files with 31 additions and 56 deletions
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65
usr.sbin/bhyve/snapshot.c
View File

@ -79,6 +79,7 @@ __FBSDID("$FreeBSD$");
#include "bhyverun.h"
#include "acpi.h"
#include "atkbdc.h"
#include "debug.h"
#include "inout.h"
#include "fwctl.h"
#include "ioapic.h"
@ -117,8 +118,6 @@ static sig_t old_winch_handler;
#define MAX_VMNAME 100
#define MAX_MSG_SIZE 1024
#define SNAPSHOT_BUFFER_SIZE (20 * MB)
#define JSON_STRUCT_ARR_KEY "structs"
@ -1442,24 +1441,10 @@ vm_checkpoint(struct vmctx *ctx, char *checkpoint_file, bool stop_vm)
}
int
get_checkpoint_msg(int conn_fd, struct vmctx *ctx)
handle_message(struct checkpoint_op *checkpoint_op, struct vmctx *ctx)
{
unsigned char buf[MAX_MSG_SIZE];
struct checkpoint_op *checkpoint_op;
int len, recv_len, total_recv = 0;
int err = 0;
int err;
len = sizeof(struct checkpoint_op); /* expected length */
while ((recv_len = recv(conn_fd, buf + total_recv, len - total_recv, 0)) > 0) {
total_recv += recv_len;
}
if (recv_len < 0) {
perror("Error while receiving data from bhyvectl");
err = -1;
goto done;
}
checkpoint_op = (struct checkpoint_op *)buf;
switch (checkpoint_op->op) {
case START_CHECKPOINT:
err = vm_checkpoint(ctx, checkpoint_op->snapshot_filename, false);
@ -1468,12 +1453,13 @@ get_checkpoint_msg(int conn_fd, struct vmctx *ctx)
err = vm_checkpoint(ctx, checkpoint_op->snapshot_filename, true);
break;
default:
fprintf(stderr, "Unrecognized checkpoint operation.\n");
EPRINTLN("Unrecognized checkpoint operation\n");
err = -1;
}
done:
close(conn_fd);
if (err != 0)
EPRINTLN("Unable to perform the requested operation\n");
return (err);
}
@ -1483,21 +1469,25 @@ get_checkpoint_msg(int conn_fd, struct vmctx *ctx)
void *
checkpoint_thread(void *param)
{
struct checkpoint_op op;
struct checkpoint_thread_info *thread_info;
int conn_fd, ret;
ssize_t n;
pthread_set_name_np(pthread_self(), "checkpoint thread");
thread_info = (struct checkpoint_thread_info *)param;
while ((conn_fd = accept(thread_info->socket_fd, NULL, NULL)) > -1) {
ret = get_checkpoint_msg(conn_fd, thread_info->ctx);
if (ret != 0) {
fprintf(stderr, "Failed to read message on checkpoint "
"socket. Retrying.\n");
}
}
if (conn_fd < -1) {
perror("Failed to accept connection");
for (;;) {
n = recvfrom(thread_info->socket_fd, &op, sizeof(op), 0, NULL, 0);
/*
* slight sanity check: see if there's enough data to at
* least determine the type of message.
*/
if (n >= sizeof(op.op))
handle_message(&op, thread_info->ctx);
else
EPRINTLN("Failed to receive message: %s\n",
n == -1 ? strerror(errno) : "unknown error");
}
return (NULL);
@ -1527,9 +1517,9 @@ init_checkpoint_thread(struct vmctx *ctx)
if (err != 0)
errc(1, err, "checkpoint cv init");
socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
socket_fd = socket(PF_UNIX, SOCK_DGRAM, 0);
if (socket_fd < 0) {
perror("Socket creation failed (IPC with bhyvectl");
EPRINTLN("Socket creation failed: %s", strerror(errno));
err = -1;
goto fail;
}
@ -1548,13 +1538,8 @@ init_checkpoint_thread(struct vmctx *ctx)
unlink(addr.sun_path);
if (bind(socket_fd, (struct sockaddr *)&addr, addr.sun_len) != 0) {
perror("Failed to bind socket (IPC with bhyvectl)");
err = -1;
goto fail;
}
if (listen(socket_fd, 10) < 0) {
perror("Failed to listen on socket (IPC with bhyvectl)");
EPRINTLN("Failed to bind socket \"%s\": %s\n",
addr.sun_path, strerror(errno));
err = -1;
goto fail;
}

22
usr.sbin/bhyvectl/bhyvectl.c
View File

@ -1687,11 +1687,11 @@ static int
send_checkpoint_op_req(struct vmctx *ctx, struct checkpoint_op *op)
{
struct sockaddr_un addr;
int socket_fd, len, len_sent, total_sent;
int err = 0;
ssize_t len_sent;
int err, socket_fd;
char vmname_buf[MAX_VMNAME];
socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
socket_fd = socket(PF_UNIX, SOCK_DGRAM, 0);
if (socket_fd < 0) {
perror("Error creating bhyvectl socket");
err = -1;
@ -1709,21 +1709,11 @@ send_checkpoint_op_req(struct vmctx *ctx, struct checkpoint_op *op)
snprintf(addr.sun_path, sizeof(addr.sun_path), "%s%s", BHYVE_RUN_DIR, vmname_buf);
if (connect(socket_fd, (struct sockaddr *)&addr,
sizeof(struct sockaddr_un)) != 0) {
perror("Connect to VM socket failed");
err = -1;
goto done;
}
len = sizeof(*op);
total_sent = 0;
while ((len_sent = send(socket_fd, (char *)op + total_sent, len - total_sent, 0)) > 0) {
total_sent += len_sent;
}
len_sent = sendto(socket_fd, op, sizeof(*op), 0,
(struct sockaddr *)&addr, sizeof(struct sockaddr_un));
if (len_sent < 0) {
perror("Failed to send checkpoint operation request");
perror("Failed to send message to bhyve vm");
err = -1;
}