6f89dc3650
It might be impractical to pass options to qrap when using libvirt, because the <emulator/> tag expects a path to an executable, without further arguments. If the first argument is not a plausible socket number, and the second argument is not a valid executable, look up a qemu command from a list of possible names, then start it patching the command line to include the -netdev fd= parameter corresponding to the AF_UNIX domain socket we just opened. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
157 lines
3.2 KiB
C
157 lines
3.2 KiB
C
// SPDX-License-Identifier: AGPL-3.0-or-later
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/* PASST - Plug A Simple Socket Transport
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*
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* qrap.c - qemu wrapper connecting UNIX domain socket to socket file descriptor
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*
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* Copyright (c) 2020-2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*
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* TODO: Implement this functionality directly in qemu: we have TCP and UDP
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* socket back-ends already.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <errno.h>
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#include <linux/if_ether.h>
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#include <linux/ipv6.h>
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#include <linux/limits.h>
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#include <limits.h>
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#include <net/if.h>
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#include "passt.h"
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static char *qemu_names[] = {
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"kvm",
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"qemu-kvm",
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#ifdef ARCH
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"qemu-system-" ARCH,
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#endif
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NULL,
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};
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#define DEFAULT_FD 5
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/**
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* usage() - Print usage and exit
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* @name: Executable name
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*/
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void usage(const char *name)
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{
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fprintf(stderr, "Usage: %s [FDNUM QEMU_CMD] ...\n", name);
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fprintf(stderr, "\n");
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fprintf(stderr, "If first and second arguments aren't a socket number\n"
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"and a path, %s will try to locate a qemu binary\n"
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"and directly patch the command line\n", name);
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exit(EXIT_FAILURE);
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}
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/**
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* main() - Entry point and main loop
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* @argc: Argument count
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* @argv: File descriptor number, then qemu with arguments
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*
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* Return: 0 once interrupted, non-zero on failure
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*/
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int main(int argc, char **argv)
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{
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char *qemu_argv[ARG_MAX], net_id[ARG_MAX] = { 0 }, *net_id_end;
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struct sockaddr_un addr = {
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.sun_family = AF_UNIX,
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.sun_path = UNIX_SOCK_PATH,
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};
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int i, s, qemu_argc = 0;
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char fd_str[ARG_MAX];
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long fd;
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if (argc >= 3) {
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fd = strtol(argv[1], NULL, 0);
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if (fd >= 3 && fd < INT_MAX && !errno) {
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char env_path[ARG_MAX], *p, command[ARG_MAX];
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strncpy(env_path, getenv("PATH"), ARG_MAX);
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p = strtok(env_path, ":");
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while (p) {
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snprintf(command, ARG_MAX, "%s/%s", p, argv[2]);
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if (!access(command, X_OK))
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goto valid_args;
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p = strtok(NULL, ":");
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}
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}
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}
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fd = DEFAULT_FD;
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for (qemu_argc = 1, i = 1; i < argc; i++) {
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char *p;
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if (!strcmp(argv[i], "-net") || (!strcmp(argv[i], "-netdev"))) {
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i++;
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continue;
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}
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if (!*net_id && (p = strstr(argv[i], ",netdev=")))
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strncpy(net_id, p + strlen(",netdev="), ARG_MAX);
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qemu_argv[qemu_argc++] = argv[i];
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}
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if (*net_id) {
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net_id_end = strpbrk(net_id, ", ");
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if (net_id_end)
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*net_id_end = 0;
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}
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qemu_argv[qemu_argc++] = "-netdev";
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snprintf(fd_str, ARG_MAX, "socket,fd=%u,id=%s", DEFAULT_FD,
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*net_id ? net_id : "hostnet0");
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qemu_argv[qemu_argc++] = fd_str;
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qemu_argv[qemu_argc] = NULL;
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valid_args:
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s = socket(AF_UNIX, SOCK_STREAM, 0);
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if (s < 0) {
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perror("socket");
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exit(EXIT_FAILURE);
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}
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if (connect(s, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
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perror("connect");
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exit(EXIT_FAILURE);
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}
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if (dup2(s, (int)fd) < 0) {
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perror("dup");
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exit(EXIT_FAILURE);
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}
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close(s);
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if (qemu_argc) {
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char *name;
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for (name = qemu_names[0]; name; name++) {
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qemu_argv[0] = name;
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execvp(name, qemu_argv);
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if (errno != ENOENT) {
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perror("execvp");
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usage(argv[0]);
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}
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}
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if (errno == ENOENT)
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fprintf(stderr, "Couldn't find qemu command\n");
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} else {
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execvp(argv[2], argv + 2);
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}
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perror("execvp");
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return EXIT_FAILURE;
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}
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