1 | #include "kernel/mod2.h" |
---|
2 | |
---|
3 | #ifdef HAVE_SIMPLEIPC |
---|
4 | #include <semaphore.h> |
---|
5 | #include <fcntl.h> |
---|
6 | #include <sys/types.h> |
---|
7 | #include <sys/stat.h> |
---|
8 | #include <stdio.h> |
---|
9 | #include <stdlib.h> |
---|
10 | #include <sys/types.h> |
---|
11 | #include <unistd.h> |
---|
12 | |
---|
13 | # include "simpleipc.h" |
---|
14 | |
---|
15 | #include "Singular/cntrlc.h" |
---|
16 | #include "reporter/si_signals.h" |
---|
17 | |
---|
18 | |
---|
19 | |
---|
20 | // Not yet implemented: SYSV IPC Semaphores |
---|
21 | // They are more difficult to clean up after a process crash |
---|
22 | // but are supported more widely. |
---|
23 | |
---|
24 | VAR sipc_sem_t *semaphore[SIPC_MAX_SEMAPHORES]; |
---|
25 | VAR int sem_acquired[SIPC_MAX_SEMAPHORES]; |
---|
26 | |
---|
27 | /* return 1 on success, |
---|
28 | * 0 if already initialized, |
---|
29 | * -1 for errors |
---|
30 | */ |
---|
31 | int sipc_semaphore_init(int id, int count) |
---|
32 | { |
---|
33 | char buf[100]; |
---|
34 | sipc_sem_t *sem; |
---|
35 | if ((id<0) || (id >= SIPC_MAX_SEMAPHORES)) |
---|
36 | return -1; |
---|
37 | // Already initialized? |
---|
38 | if (semaphore[id]) |
---|
39 | return 0; |
---|
40 | // to make it completely safe, we should generate a name |
---|
41 | // from /dev/urandom. |
---|
42 | #if USE_SEM_INIT |
---|
43 | // TODO: This should really use mapped memory so that processes |
---|
44 | // can keep using the semaphore after fork + exec. |
---|
45 | sem = malloc(sizeof(sem_t)); |
---|
46 | if (!sem) |
---|
47 | return -1; |
---|
48 | if (sem_init(sem, 1, count) < 0) |
---|
49 | { |
---|
50 | free(sem); |
---|
51 | return -1; |
---|
52 | } |
---|
53 | #else |
---|
54 | #if PORTABLE_SEMAPHORES |
---|
55 | #ifndef MAP_ANONYMOUS |
---|
56 | #define MAP_ANONYMOUS MAP_ANON |
---|
57 | #endif |
---|
58 | sem = mmap(NULL, getpagesize(), |
---|
59 | PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_SHARED, -1, 0); |
---|
60 | if (sem == MAP_FAILED) |
---|
61 | return -1; |
---|
62 | sem->count = count; |
---|
63 | sprintf(buf, "/%d:sem%d:g", getpid(), id); |
---|
64 | sem_unlink(buf); |
---|
65 | sem->guard = sem_open(buf, O_CREAT, 0600, count); |
---|
66 | sem_unlink(buf); |
---|
67 | sprintf(buf, "/%d:sem%d:s", getpid(), id); |
---|
68 | sem_unlink(buf); |
---|
69 | sem->sig = sem_open(buf, O_CREAT, 0600, count); |
---|
70 | sem_unlink(buf); |
---|
71 | #else |
---|
72 | sprintf(buf, "/%d:sem%d", getpid(), id); |
---|
73 | sem_unlink(buf); |
---|
74 | sem = sem_open(buf, O_CREAT, 0600, count); |
---|
75 | #endif |
---|
76 | #endif |
---|
77 | #if !PORTABLE_SEMAPHORES |
---|
78 | if (sem == SEM_FAILED || !sem) |
---|
79 | return -1; |
---|
80 | #endif |
---|
81 | semaphore[id] = sem; |
---|
82 | #if !USE_SEM_INIT |
---|
83 | sem_unlink(buf); |
---|
84 | #endif |
---|
85 | return 1; |
---|
86 | } |
---|
87 | |
---|
88 | int sipc_semaphore_exists(int id) |
---|
89 | { |
---|
90 | if ((id<0) || (id >= SIPC_MAX_SEMAPHORES)) return -1; |
---|
91 | return semaphore[id] != NULL; |
---|
92 | } |
---|
93 | |
---|
94 | int sipc_semaphore_acquire(int id) |
---|
95 | { |
---|
96 | if ((id<0) || (id >= SIPC_MAX_SEMAPHORES) || (semaphore[id]==NULL)) return -1; |
---|
97 | defer_shutdown++; |
---|
98 | #if PORTABLE_SEMAPHORES |
---|
99 | si_sem_wait(semaphore[id]->sig); |
---|
100 | si_sem_wait(semaphore[id]->guard); |
---|
101 | semaphore[id]->count--; |
---|
102 | sem_post(semaphore[id]->guard); |
---|
103 | #else |
---|
104 | si_sem_wait(semaphore[id]); |
---|
105 | #endif |
---|
106 | sem_acquired[id]++; |
---|
107 | defer_shutdown--; |
---|
108 | if (!defer_shutdown && do_shutdown) m2_end(1); |
---|
109 | return 1; |
---|
110 | } |
---|
111 | |
---|
112 | int sipc_semaphore_try_acquire(int id) |
---|
113 | { |
---|
114 | if ((id<0) || (id >= SIPC_MAX_SEMAPHORES) || (semaphore[id]==NULL)) return -1; |
---|
115 | defer_shutdown++; |
---|
116 | #if PORTABLE_SEMAPHORES |
---|
117 | int trywait = si_sem_trywait(semaphore[id]->sig); |
---|
118 | #else |
---|
119 | int trywait = si_sem_trywait(semaphore[id]); |
---|
120 | #endif |
---|
121 | if (!trywait) |
---|
122 | { |
---|
123 | #if PORTABLE_SEMAPHORES |
---|
124 | si_sem_wait(semaphore[id]->guard); |
---|
125 | semaphore[id]->count--; |
---|
126 | sem_post(semaphore[id]->guard); |
---|
127 | #endif |
---|
128 | sem_acquired[id]++; |
---|
129 | } |
---|
130 | defer_shutdown--; |
---|
131 | if (!defer_shutdown && do_shutdown) m2_end(1); |
---|
132 | return !trywait; |
---|
133 | } |
---|
134 | |
---|
135 | int sipc_semaphore_release(int id) |
---|
136 | { |
---|
137 | if ((id<0) || (id >= SIPC_MAX_SEMAPHORES) || (semaphore[id]==NULL)) return -1; |
---|
138 | defer_shutdown++; |
---|
139 | #if PORTABLE_SEMAPHORES |
---|
140 | sem_wait(semaphore[id]->guard); |
---|
141 | semaphore[id]->count++; |
---|
142 | sem_post(semaphore[id]->sig); |
---|
143 | sem_post(semaphore[id]->guard); |
---|
144 | #else |
---|
145 | sem_post(semaphore[id]); |
---|
146 | #endif |
---|
147 | sem_acquired[id]--; |
---|
148 | defer_shutdown--; |
---|
149 | if (!defer_shutdown && do_shutdown) m2_end(1); |
---|
150 | return 1; |
---|
151 | } |
---|
152 | |
---|
153 | int sipc_semaphore_get_value(int id) |
---|
154 | { |
---|
155 | int val; |
---|
156 | if ((id<0) || (id >= SIPC_MAX_SEMAPHORES) || (semaphore[id]==NULL)) return -1; |
---|
157 | #if PORTABLE_SEMAPHORES |
---|
158 | sem_wait(semaphore[id]->guard); |
---|
159 | val = semaphore[id]->count; |
---|
160 | sem_post(semaphore[id]->guard); |
---|
161 | #else |
---|
162 | sem_getvalue(semaphore[id], &val); |
---|
163 | #endif |
---|
164 | return val; |
---|
165 | } |
---|
166 | |
---|
167 | int simpleipc_cmd(char *cmd, int id, int v) |
---|
168 | { |
---|
169 | if (strcmp(cmd,"init")==0) |
---|
170 | return sipc_semaphore_init(id,v); |
---|
171 | else if (strcmp(cmd,"exists")==0) |
---|
172 | return sipc_semaphore_exists(id); |
---|
173 | else if (strcmp(cmd,"acquire")==0) |
---|
174 | return sipc_semaphore_acquire(id); |
---|
175 | else if (strcmp(cmd,"try_acquire")==0) |
---|
176 | return sipc_semaphore_try_acquire(id); |
---|
177 | else if (strcmp(cmd,"release")==0) |
---|
178 | return sipc_semaphore_release(id); |
---|
179 | else if (strcmp(cmd,"get_value")==0) |
---|
180 | return sipc_semaphore_get_value(id); |
---|
181 | else printf("unknown\n"); |
---|
182 | return -2; |
---|
183 | } |
---|
184 | #endif |
---|