xref: /openbmc/qemu/contrib/ivshmem-server/main.c (revision ba632924)
1 /*
2  * Copyright 6WIND S.A., 2014
3  *
4  * This work is licensed under the terms of the GNU GPL, version 2 or
5  * (at your option) any later version.  See the COPYING file in the
6  * top-level directory.
7  */
8 
9 #include "qemu/osdep.h"
10 #include "qapi/error.h"
11 #include "qemu/cutils.h"
12 #include "qemu/option.h"
13 #include "ivshmem-server.h"
14 
15 #define IVSHMEM_SERVER_DEFAULT_VERBOSE        0
16 #define IVSHMEM_SERVER_DEFAULT_FOREGROUND     0
17 #define IVSHMEM_SERVER_DEFAULT_PID_FILE       "/var/run/ivshmem-server.pid"
18 #define IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH "/tmp/ivshmem_socket"
19 #define IVSHMEM_SERVER_DEFAULT_SHM_PATH       "ivshmem"
20 #define IVSHMEM_SERVER_DEFAULT_SHM_SIZE       (4*1024*1024)
21 #define IVSHMEM_SERVER_DEFAULT_N_VECTORS      1
22 
23 /* used to quit on signal SIGTERM */
24 static int ivshmem_server_quit;
25 
26 /* arguments given by the user */
27 typedef struct IvshmemServerArgs {
28     bool verbose;
29     bool foreground;
30     const char *pid_file;
31     const char *unix_socket_path;
32     const char *shm_path;
33     bool use_shm_open;
34     uint64_t shm_size;
35     unsigned n_vectors;
36 } IvshmemServerArgs;
37 
38 static void
39 ivshmem_server_usage(const char *progname)
40 {
41     printf("Usage: %s [OPTION]...\n"
42            "  -h: show this help\n"
43            "  -v: verbose mode\n"
44            "  -F: foreground mode (default is to daemonize)\n"
45            "  -p <pid-file>: path to the PID file (used in daemon mode only)\n"
46            "     default " IVSHMEM_SERVER_DEFAULT_PID_FILE "\n"
47            "  -S <unix-socket-path>: path to the unix socket to listen to\n"
48            "     default " IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH "\n"
49            "  -M <shm-name>: POSIX shared memory object to use\n"
50            "     default " IVSHMEM_SERVER_DEFAULT_SHM_PATH "\n"
51            "  -m <dir-name>: where to create shared memory\n"
52            "  -l <size>: size of shared memory in bytes\n"
53            "     suffixes K, M and G can be used, e.g. 1K means 1024\n"
54            "     default %u\n"
55            "  -n <nvectors>: number of vectors\n"
56            "     default %u\n",
57            progname, IVSHMEM_SERVER_DEFAULT_SHM_SIZE,
58            IVSHMEM_SERVER_DEFAULT_N_VECTORS);
59 }
60 
61 static void
62 ivshmem_server_help(const char *progname)
63 {
64     fprintf(stderr, "Try '%s -h' for more information.\n", progname);
65 }
66 
67 /* parse the program arguments, exit on error */
68 static void
69 ivshmem_server_parse_args(IvshmemServerArgs *args, int argc, char *argv[])
70 {
71     int c;
72     unsigned long long v;
73     Error *err = NULL;
74 
75     while ((c = getopt(argc, argv, "hvFp:S:m:M:l:n:")) != -1) {
76 
77         switch (c) {
78         case 'h': /* help */
79             ivshmem_server_usage(argv[0]);
80             exit(0);
81             break;
82 
83         case 'v': /* verbose */
84             args->verbose = 1;
85             break;
86 
87         case 'F': /* foreground */
88             args->foreground = 1;
89             break;
90 
91         case 'p': /* pid file */
92             args->pid_file = optarg;
93             break;
94 
95         case 'S': /* unix socket path */
96             args->unix_socket_path = optarg;
97             break;
98 
99         case 'M': /* shm name */
100         case 'm': /* dir name */
101             args->shm_path = optarg;
102             args->use_shm_open = c == 'M';
103             break;
104 
105         case 'l': /* shm size */
106             parse_option_size("shm_size", optarg, &args->shm_size, &err);
107             if (err) {
108                 error_report_err(err);
109                 ivshmem_server_help(argv[0]);
110                 exit(1);
111             }
112             break;
113 
114         case 'n': /* number of vectors */
115             if (parse_uint_full(optarg, &v, 0) < 0) {
116                 fprintf(stderr, "cannot parse n_vectors\n");
117                 ivshmem_server_help(argv[0]);
118                 exit(1);
119             }
120             args->n_vectors = v;
121             break;
122 
123         default:
124             ivshmem_server_usage(argv[0]);
125             exit(1);
126             break;
127         }
128     }
129 
130     if (args->n_vectors > IVSHMEM_SERVER_MAX_VECTORS) {
131         fprintf(stderr, "too many requested vectors (max is %d)\n",
132                 IVSHMEM_SERVER_MAX_VECTORS);
133         ivshmem_server_help(argv[0]);
134         exit(1);
135     }
136 
137     if (args->verbose == 1 && args->foreground == 0) {
138         fprintf(stderr, "cannot use verbose in daemon mode\n");
139         ivshmem_server_help(argv[0]);
140         exit(1);
141     }
142 }
143 
144 /* wait for events on listening server unix socket and connected client
145  * sockets */
146 static int
147 ivshmem_server_poll_events(IvshmemServer *server)
148 {
149     fd_set fds;
150     int ret = 0, maxfd;
151 
152     while (!ivshmem_server_quit) {
153 
154         FD_ZERO(&fds);
155         maxfd = 0;
156         ivshmem_server_get_fds(server, &fds, &maxfd);
157 
158         ret = select(maxfd, &fds, NULL, NULL, NULL);
159 
160         if (ret < 0) {
161             if (errno == EINTR) {
162                 continue;
163             }
164 
165             fprintf(stderr, "select error: %s\n", strerror(errno));
166             break;
167         }
168         if (ret == 0) {
169             continue;
170         }
171 
172         if (ivshmem_server_handle_fds(server, &fds, maxfd) < 0) {
173             fprintf(stderr, "ivshmem_server_handle_fds() failed\n");
174             break;
175         }
176     }
177 
178     return ret;
179 }
180 
181 static void
182 ivshmem_server_quit_cb(int signum)
183 {
184     ivshmem_server_quit = 1;
185 }
186 
187 int
188 main(int argc, char *argv[])
189 {
190     IvshmemServer server;
191     struct sigaction sa, sa_quit;
192     IvshmemServerArgs args = {
193         .verbose = IVSHMEM_SERVER_DEFAULT_VERBOSE,
194         .foreground = IVSHMEM_SERVER_DEFAULT_FOREGROUND,
195         .pid_file = IVSHMEM_SERVER_DEFAULT_PID_FILE,
196         .unix_socket_path = IVSHMEM_SERVER_DEFAULT_UNIX_SOCK_PATH,
197         .shm_path = IVSHMEM_SERVER_DEFAULT_SHM_PATH,
198         .use_shm_open = true,
199         .shm_size = IVSHMEM_SERVER_DEFAULT_SHM_SIZE,
200         .n_vectors = IVSHMEM_SERVER_DEFAULT_N_VECTORS,
201     };
202     int ret = 1;
203 
204     /*
205      * Do not remove this notice without adding proper error handling!
206      * Start with handling ivshmem_server_send_one_msg() failure.
207      */
208     printf("*** Example code, do not use in production ***\n");
209 
210     /* parse arguments, will exit on error */
211     ivshmem_server_parse_args(&args, argc, argv);
212 
213     /* Ignore SIGPIPE, see this link for more info:
214      * http://www.mail-archive.com/libevent-users@monkey.org/msg01606.html */
215     sa.sa_handler = SIG_IGN;
216     sa.sa_flags = 0;
217     if (sigemptyset(&sa.sa_mask) == -1 ||
218         sigaction(SIGPIPE, &sa, 0) == -1) {
219         perror("failed to ignore SIGPIPE; sigaction");
220         goto err;
221     }
222 
223     sa_quit.sa_handler = ivshmem_server_quit_cb;
224     sa_quit.sa_flags = 0;
225     if (sigemptyset(&sa_quit.sa_mask) == -1 ||
226         sigaction(SIGTERM, &sa_quit, 0) == -1) {
227         perror("failed to add SIGTERM handler; sigaction");
228         goto err;
229     }
230 
231     /* init the ivshms structure */
232     if (ivshmem_server_init(&server, args.unix_socket_path,
233                             args.shm_path, args.use_shm_open,
234                             args.shm_size, args.n_vectors, args.verbose) < 0) {
235         fprintf(stderr, "cannot init server\n");
236         goto err;
237     }
238 
239     /* start the ivshmem server (open shm & unix socket) */
240     if (ivshmem_server_start(&server) < 0) {
241         fprintf(stderr, "cannot bind\n");
242         goto err;
243     }
244 
245     /* daemonize if asked to */
246     if (!args.foreground) {
247         FILE *fp;
248 
249         if (qemu_daemon(1, 1) < 0) {
250             fprintf(stderr, "cannot daemonize: %s\n", strerror(errno));
251             goto err_close;
252         }
253 
254         /* write pid file */
255         fp = fopen(args.pid_file, "w");
256         if (fp == NULL) {
257             fprintf(stderr, "cannot write pid file: %s\n", strerror(errno));
258             goto err_close;
259         }
260 
261         fprintf(fp, "%d\n", (int) getpid());
262         fclose(fp);
263     }
264 
265     ivshmem_server_poll_events(&server);
266     fprintf(stdout, "server disconnected\n");
267     ret = 0;
268 
269 err_close:
270     ivshmem_server_close(&server);
271 err:
272     return ret;
273 }
274