1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2000 Andrzej Bialecki <abial@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/types.h> 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/module.h> 33 #include <sys/sysctl.h> 34 #include <sys/kernel.h> 35 36 37 /* Some example data */ 38 static long a = 100; 39 static int b = 200; 40 static char *c = "hi there from dyn_sysctl"; 41 static struct sysctl_oid *a_root, *a_root1, *b_root; 42 static struct sysctl_ctx_list clist, clist1, clist2; 43 44 static int 45 sysctl_dyn_sysctl_test(SYSCTL_HANDLER_ARGS) 46 { 47 char *buf = "let's produce some text..."; 48 49 return (sysctl_handle_string(oidp, buf, strlen(buf), req)); 50 } 51 52 /* 53 * The function called at load/unload. 54 */ 55 static int 56 load(module_t mod, int cmd, void *arg) 57 { 58 int error; 59 60 error = 0; 61 switch (cmd) { 62 case MOD_LOAD: 63 /* Initialize the contexts */ 64 printf("Initializing contexts and creating subtrees.\n\n"); 65 sysctl_ctx_init(&clist); 66 sysctl_ctx_init(&clist1); 67 sysctl_ctx_init(&clist2); 68 /* 69 * Create two partially overlapping subtrees, belonging 70 * to different contexts. 71 */ 72 printf("TREE ROOT NAME\n"); 73 a_root = SYSCTL_ADD_ROOT_NODE(&clist, 74 OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, 75 "dyn_sysctl root node"); 76 a_root = SYSCTL_ADD_ROOT_NODE(&clist1, 77 OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, 78 "dyn_sysctl root node"); 79 if (a_root == NULL) { 80 printf("SYSCTL_ADD_NODE failed!\n"); 81 return (EINVAL); 82 } 83 SYSCTL_ADD_LONG(&clist, SYSCTL_CHILDREN(a_root), 84 OID_AUTO, "long_a", CTLFLAG_RW, &a, "just to try"); 85 SYSCTL_ADD_INT(&clist, SYSCTL_CHILDREN(a_root), 86 OID_AUTO, "int_b", CTLFLAG_RW, &b, 0, "just to try 1"); 87 a_root1 = SYSCTL_ADD_NODE(&clist, SYSCTL_CHILDREN(a_root), 88 OID_AUTO, "nextlevel", CTLFLAG_RD, 0, "one level down"); 89 SYSCTL_ADD_STRING(&clist, SYSCTL_CHILDREN(a_root1), 90 OID_AUTO, "string_c", CTLFLAG_RD, c, 0, "just to try 2"); 91 printf("1. (%p) / dyn_sysctl\n", &clist); 92 93 /* Add a subtree under already existing category */ 94 a_root1 = SYSCTL_ADD_NODE(&clist, SYSCTL_STATIC_CHILDREN(_kern), 95 OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, "dyn_sysctl root node"); 96 if (a_root1 == NULL) { 97 printf("SYSCTL_ADD_NODE failed!\n"); 98 return (EINVAL); 99 } 100 SYSCTL_ADD_PROC(&clist, SYSCTL_CHILDREN(a_root1), 101 OID_AUTO, "procedure", CTLTYPE_STRING | CTLFLAG_RD, 102 NULL, 0, sysctl_dyn_sysctl_test, "A", 103 "I can be here, too"); 104 printf(" (%p) /kern dyn_sysctl\n", &clist); 105 106 /* Overlap second tree with the first. */ 107 b_root = SYSCTL_ADD_NODE(&clist1, SYSCTL_CHILDREN(a_root), 108 OID_AUTO, "nextlevel", CTLFLAG_RD, 0, "one level down"); 109 SYSCTL_ADD_STRING(&clist1, SYSCTL_CHILDREN(b_root), 110 OID_AUTO, "string_c1", CTLFLAG_RD, c, 0, "just to try 2"); 111 printf("2. (%p) / dyn_sysctl (overlapping #1)\n", &clist1); 112 113 /* 114 * And now do something stupid. Connect another subtree to 115 * dynamic oid. 116 * WARNING: this is an example of WRONG use of dynamic sysctls. 117 */ 118 b_root=SYSCTL_ADD_NODE(&clist2, SYSCTL_CHILDREN(a_root1), 119 OID_AUTO, "bad", CTLFLAG_RW, 0, "dependent node"); 120 SYSCTL_ADD_STRING(&clist2, SYSCTL_CHILDREN(b_root), 121 OID_AUTO, "string_c", CTLFLAG_RD, c, 0, "shouldn't panic"); 122 printf("3. (%p) /kern/dyn_sysctl bad (WRONG!)\n", &clist2); 123 break; 124 case MOD_UNLOAD: 125 printf("1. Try to free ctx1 (%p): ", &clist); 126 if (sysctl_ctx_free(&clist) != 0) 127 printf("failed: expected. Need to remove ctx3 first.\n"); 128 else 129 printf("HELP! sysctl_ctx_free(%p) succeeded. EXPECT PANIC!!!\n", &clist); 130 printf("2. Try to free ctx3 (%p): ", &clist2); 131 if (sysctl_ctx_free(&clist2) != 0) { 132 printf("sysctl_ctx_free(%p) failed!\n", &clist2); 133 /* Remove subtree forcefully... */ 134 sysctl_remove_oid(b_root, 1, 1); 135 printf("sysctl_remove_oid(%p) succeeded\n", b_root); 136 } else 137 printf("Ok\n"); 138 printf("3. Try to free ctx1 (%p) again: ", &clist); 139 if (sysctl_ctx_free(&clist) != 0) { 140 printf("sysctl_ctx_free(%p) failed!\n", &clist); 141 /* Remove subtree forcefully... */ 142 sysctl_remove_oid(a_root1, 1, 1); 143 printf("sysctl_remove_oid(%p) succeeded\n", a_root1); 144 } else 145 printf("Ok\n"); 146 printf("4. Try to free ctx2 (%p): ", &clist1); 147 if (sysctl_ctx_free(&clist1) != 0) { 148 printf("sysctl_ctx_free(%p) failed!\n", &clist1); 149 /* Remove subtree forcefully... */ 150 sysctl_remove_oid(a_root, 1, 1); 151 } else 152 printf("Ok\n"); 153 break; 154 default: 155 error = EOPNOTSUPP; 156 break; 157 } 158 return (error); 159 } 160 161 static moduledata_t mod_data = { 162 "dyn_sysctl", 163 load, 164 0 165 }; 166 167 DECLARE_MODULE(dyn_sysctl, mod_data, SI_SUB_EXEC, SI_ORDER_ANY); 168