Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * test_shmem.c
4 : : * Helpers to test shmem allocation routines
5 : : *
6 : : * Test basic memory allocation in an extension module. One notable feature
7 : : * that is not exercised by any other module in the repository is the
8 : : * allocating (non-DSM) shared memory after postmaster startup.
9 : : *
10 : : * Copyright (c) 2020-2026, PostgreSQL Global Development Group
11 : : *
12 : : * IDENTIFICATION
13 : : * src/test/modules/test_shmem/test_shmem.c
14 : : *
15 : : *-------------------------------------------------------------------------
16 : : */
17 : :
18 : : #include "postgres.h"
19 : :
20 : : #include "fmgr.h"
21 : : #include "miscadmin.h"
22 : : #include "storage/shmem.h"
23 : : #include "utils/guc.h"
24 : : #include "utils/injection_point.h"
25 : :
26 : :
167 heikki.linnakangas@i 27 :CBC 10 : PG_MODULE_MAGIC;
28 : :
29 : : typedef struct TestShmemData
30 : : {
31 : : bool initialized;
32 : : int attach_count;
33 : : char dummy_data[FLEXIBLE_ARRAY_MEMBER];
34 : : } TestShmemData;
35 : :
36 : : static TestShmemData *TestShmem;
37 : :
38 : : #define DEFAULT_TEST_AREA_BYTES sizeof(TestShmemData)
39 : : #define MAX_TEST_AREA_BYTES 1000000
40 : :
41 : : static bool attached_or_initialized = false;
42 : : static int test_shmem_area_size = DEFAULT_TEST_AREA_BYTES;
43 : : static bool test_shmem_guc_defined = false;
44 : :
45 : : static void test_shmem_request(void *arg);
46 : : static void test_shmem_init(void *arg);
47 : : static void test_shmem_attach(void *arg);
48 : :
49 : : static const ShmemCallbacks TestShmemCallbacks = {
50 : : .flags = SHMEM_CALLBACKS_ALLOW_AFTER_STARTUP,
51 : : .request_fn = test_shmem_request,
52 : : .init_fn = test_shmem_init,
53 : : .attach_fn = test_shmem_attach,
54 : : };
55 : :
56 : : static void
57 : 10 : test_shmem_request(void *arg)
58 : : {
59 [ + - ]: 10 : elog(LOG, "test_shmem_request callback called");
60 : :
61 : 10 : ShmemRequestStruct(.name = "test_shmem area",
62 : : .size = test_shmem_area_size,
63 : : .ptr = (void **) &TestShmem);
64 : 10 : }
65 : :
66 : : static void
67 : 6 : test_shmem_init(void *arg)
68 : : {
69 [ + - ]: 6 : elog(LOG, "init callback called");
70 : :
23 71 : 6 : INJECTION_POINT("test-shmem-init", NULL);
72 : :
167 73 [ - + ]: 5 : if (TestShmem->initialized)
167 heikki.linnakangas@i 74 [ # # ]:UBC 0 : elog(ERROR, "shmem area already initialized");
167 heikki.linnakangas@i 75 :CBC 5 : TestShmem->initialized = true;
76 : :
77 [ - + ]: 5 : if (attached_or_initialized)
167 heikki.linnakangas@i 78 [ # # ]:UBC 0 : elog(ERROR, "attach or initialize already called in this process");
167 heikki.linnakangas@i 79 :CBC 5 : attached_or_initialized = true;
80 : 5 : }
81 : :
82 : : static void
83 : 1 : test_shmem_attach(void *arg)
84 : : {
85 [ + - ]: 1 : elog(LOG, "test_shmem_attach callback called");
86 [ - + ]: 1 : if (!TestShmem->initialized)
167 heikki.linnakangas@i 87 [ # # ]:UBC 0 : elog(ERROR, "shmem area not yet initialized");
167 heikki.linnakangas@i 88 :CBC 1 : TestShmem->attach_count++;
89 : :
90 [ - + ]: 1 : if (attached_or_initialized)
167 heikki.linnakangas@i 91 [ # # ]:UBC 0 : elog(ERROR, "attach or initialize already called in this process");
167 heikki.linnakangas@i 92 :CBC 1 : attached_or_initialized = true;
93 : 1 : }
94 : :
95 : : void
96 : 10 : _PG_init(void)
97 : : {
98 [ + - ]: 10 : elog(LOG, "test_shmem module's _PG_init called");
99 : :
23 100 [ + + ]: 10 : if (!test_shmem_guc_defined)
101 : : {
102 : : /*
103 : : * The minimum size that makes sense is sizeof(TestShmemData), but we
104 : : * allow -1 so that we can test passing SHMEM_ATTACH_UNKNOWN_SIZE.
105 : : */
106 : 9 : DefineCustomIntVariable("test_shmem.area_size",
107 : : "Size of the shmem area to request.",
108 : : NULL,
109 : : &test_shmem_area_size,
110 : : DEFAULT_TEST_AREA_BYTES,
111 : : -1,
112 : : MAX_TEST_AREA_BYTES,
113 : : PGC_USERSET,
114 : : GUC_UNIT_BYTE,
115 : : NULL, NULL, NULL);
116 : 9 : MarkGUCPrefixReserved("test_shmem");
117 : 9 : test_shmem_guc_defined = true;
118 : : }
167 119 : 10 : RegisterShmemCallbacks(&TestShmemCallbacks);
120 : 6 : }
121 : :
122 : 7 : PG_FUNCTION_INFO_V1(get_test_shmem_attach_count);
123 : : Datum
124 : 6 : get_test_shmem_attach_count(PG_FUNCTION_ARGS)
125 : : {
126 [ - + ]: 6 : if (!attached_or_initialized)
167 heikki.linnakangas@i 127 [ # # ]:UBC 0 : elog(ERROR, "shmem area not attached or initialized in this process");
167 heikki.linnakangas@i 128 [ - + ]:CBC 6 : if (!TestShmem->initialized)
167 heikki.linnakangas@i 129 [ # # ]:UBC 0 : elog(ERROR, "shmem area not yet initialized");
167 heikki.linnakangas@i 130 :CBC 6 : PG_RETURN_INT32(TestShmem->attach_count);
131 : : }
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