xref: /dpdk/examples/l2fwd-keepalive/shm.c (revision 13830b98b2bcf6a8a1aa8edde5132907c053861c)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2016 Intel Corporation
3  */
4 
5 #include <time.h>
6 
7 #include <rte_common.h>
8 #include <rte_keepalive.h>
9 
10 #include "shm.h"
11 
rte_keepalive_shm_create(void)12 struct rte_keepalive_shm *rte_keepalive_shm_create(void)
13 {
14 	int fd;
15 	int idx_core;
16 	struct rte_keepalive_shm *ka_shm;
17 
18 	/* If any existing object is not unlinked, it makes it all too easy
19 	 * for clients to end up with stale shared memory blocks when
20 	 * restarted. Unlinking makes sure subsequent shm_open by clients
21 	 * will get the new block mapped below.
22 	 */
23 	if (shm_unlink(RTE_KEEPALIVE_SHM_NAME) == -1 && errno != ENOENT)
24 		RTE_LOG(NOTICE, L2FWD,
25 			"Warning: Error unlinking stale %s (%s)\n",
26 			RTE_KEEPALIVE_SHM_NAME, strerror(errno));
27 
28 	fd = shm_open(RTE_KEEPALIVE_SHM_NAME,
29 		O_CREAT | O_TRUNC | O_RDWR, 0666);
30 	if (fd < 0)
31 		RTE_LOG(ERR, L2FWD, "Failed to open %s as SHM (%s)\n",
32 			RTE_KEEPALIVE_SHM_NAME, strerror(errno));
33 	else if (ftruncate(fd, sizeof(struct rte_keepalive_shm)) != 0)
34 		RTE_LOG(ERR, L2FWD, "Failed to resize SHM (%s)\n", strerror(errno));
35 	else {
36 		ka_shm = (struct rte_keepalive_shm *) mmap(
37 			0, sizeof(struct rte_keepalive_shm),
38 			PROT_READ | PROT_WRITE,	MAP_SHARED, fd, 0);
39 		close(fd);
40 		if (ka_shm == MAP_FAILED)
41 			RTE_LOG(ERR, L2FWD, "Failed to mmap SHM (%s)\n", strerror(errno));
42 		else {
43 			memset(ka_shm, 0, sizeof(struct rte_keepalive_shm));
44 
45 			/* Initialize the semaphores for IPC/SHM use */
46 			if (sem_init(&ka_shm->core_died, 1, 0) != 0) {
47 				RTE_LOG(ERR, L2FWD, "Failed to setup SHM semaphore (%s)\n",
48 					strerror(errno));
49 				munmap(ka_shm,
50 					sizeof(struct rte_keepalive_shm));
51 				return NULL;
52 			}
53 
54 			/* Set all cores to 'not present' */
55 			for (idx_core = 0;
56 					idx_core < RTE_KEEPALIVE_MAXCORES;
57 					idx_core++) {
58 				ka_shm->core_state[idx_core] =
59 					RTE_KA_STATE_UNUSED;
60 				ka_shm->core_last_seen_times[idx_core] = 0;
61 			}
62 
63 			return ka_shm;
64 		}
65 	}
66 return NULL;
67 }
68 
rte_keepalive_relayed_state(struct rte_keepalive_shm * shm,const int id_core,const enum rte_keepalive_state core_state,__rte_unused uint64_t last_alive)69 void rte_keepalive_relayed_state(struct rte_keepalive_shm *shm,
70 	const int id_core, const enum rte_keepalive_state core_state,
71 	__rte_unused uint64_t last_alive)
72 {
73 	int count;
74 
75 	shm->core_state[id_core] = core_state;
76 	shm->core_last_seen_times[id_core] = last_alive;
77 
78 	if (core_state == RTE_KEEPALIVE_SHM_DEAD) {
79 		/* Since core has died, also signal ka_agent.
80 		 *
81 		 * Limit number of times semaphore can be incremented, in case
82 		 * ka_agent is not active.
83 		 */
84 		if (sem_getvalue(&shm->core_died, &count) == -1) {
85 			RTE_LOG(ERR, L2FWD, "Semaphore check failed(%s)\n",
86 				strerror(errno));
87 			return;
88 		}
89 		if (count > 1)
90 			return;
91 
92 		if (sem_post(&shm->core_died) != 0)
93 			RTE_LOG(ERR, L2FWD, "Failed to increment semaphore (%s)\n",
94 				strerror(errno));
95 	}
96 }
97 
rte_keepalive_shm_cleanup(struct rte_keepalive_shm * ka_shm)98 void rte_keepalive_shm_cleanup(struct rte_keepalive_shm *ka_shm)
99 {
100 	if (shm_unlink(RTE_KEEPALIVE_SHM_NAME) == -1 && errno != ENOENT)
101 		RTE_LOG(NOTICE, L2FWD, "Warning: Error unlinking  %s (%s)\n",
102 			RTE_KEEPALIVE_SHM_NAME, strerror(errno));
103 
104 	if (ka_shm && munmap(ka_shm, sizeof(struct rte_keepalive_shm)) != 0)
105 		RTE_LOG(ERR, L2FWD, "Warning: munmap() failed: %s\n",
106 			strerror(errno));
107 }
108