dyn_sysctl.c revision 72336
1/*- 2 * Copyright (c) 2000 Andrzej Bialecki <abial@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: head/share/examples/kld/dyn_sysctl/dyn_sysctl.c 72336 2001-02-10 22:36:05Z abial $ 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 */ 38static long a = 100; 39static int b = 200; 40static char *c = "hi there from dyn_sysctl"; 41static struct sysctl_oid *a_root, *a_root1, *b_root; 42static struct sysctl_ctx_list clist, clist1, clist2; 43 44static int 45sysctl_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 */ 55static int 56load (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_NODE(&clist, 74 SYSCTL_STATIC_CHILDREN(/* top of sysctl tree */), 75 OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, 76 "dyn_sysctl root node"); 77 a_root = SYSCTL_ADD_NODE(&clist1, 78 SYSCTL_STATIC_CHILDREN(/* top of sysctl tree */), 79 OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, 80 "dyn_sysctl root node"); 81 if(a_root == NULL) { 82 printf("SYSCTL_ADD_NODE failed!\n"); 83 return (EINVAL); 84 } 85 SYSCTL_ADD_LONG(&clist, SYSCTL_CHILDREN(a_root), 86 OID_AUTO, "long_a", CTLFLAG_RW, &a, "just to try"); 87 SYSCTL_ADD_INT(&clist, SYSCTL_CHILDREN(a_root), 88 OID_AUTO, "int_b", CTLFLAG_RW, &b, 0, "just to try 1"); 89 a_root1=SYSCTL_ADD_NODE(&clist, SYSCTL_CHILDREN(a_root), 90 OID_AUTO, "nextlevel", CTLFLAG_RD, 0, "one level down"); 91 SYSCTL_ADD_STRING(&clist, SYSCTL_CHILDREN(a_root1), 92 OID_AUTO, "string_c", CTLFLAG_RD, c, 0, "just to try 2"); 93 printf("1. (%p) / dyn_sysctl\n", &clist); 94 95 /* Add a subtree under already existing category */ 96 a_root1 = SYSCTL_ADD_NODE(&clist, SYSCTL_STATIC_CHILDREN(_kern), 97 OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, "dyn_sysctl root node"); 98 if(a_root1 == NULL) { 99 printf("SYSCTL_ADD_NODE failed!\n"); 100 return (EINVAL); 101 } 102 SYSCTL_ADD_PROC(&clist, SYSCTL_CHILDREN(a_root1), 103 OID_AUTO, "procedure", CTLFLAG_RD, 0, 0, 104 sysctl_dyn_sysctl_test, "A", "I can be here, too"); 105 printf(" (%p) /kern dyn_sysctl\n", &clist); 106 107 /* Overlap second tree with the first. */ 108 b_root = SYSCTL_ADD_NODE(&clist1, SYSCTL_CHILDREN(a_root), 109 OID_AUTO, "nextlevel", CTLFLAG_RD, 0, "one level down"); 110 SYSCTL_ADD_STRING(&clist1, SYSCTL_CHILDREN(b_root), 111 OID_AUTO, "string_c1", CTLFLAG_RD, c, 0, "just to try 2"); 112 printf("2. (%p) / dyn_sysctl (overlapping #1)\n", &clist1); 113 114 /* 115 * And now do something stupid. Connect another subtree to 116 * dynamic oid. 117 * WARNING: this is an example of WRONG use of dynamic sysctls. 118 */ 119 b_root=SYSCTL_ADD_NODE(&clist2, SYSCTL_CHILDREN(a_root1), 120 OID_AUTO, "bad", CTLFLAG_RW, 0, "dependent node"); 121 SYSCTL_ADD_STRING(&clist2, SYSCTL_CHILDREN(b_root), 122 OID_AUTO, "string_c", CTLFLAG_RD, c, 0, "shouldn't panic"); 123 printf("3. (%p) /kern/dyn_sysctl bad (WRONG!)\n", &clist2); 124 break; 125 case MOD_UNLOAD : 126 printf("1. Try to free ctx1 (%p): ", &clist); 127 if(sysctl_ctx_free(&clist)) 128 printf("failed: expected. Need to remove ctx3 first.\n"); 129 else 130 printf("HELP! sysctl_ctx_free(%p) succeeded. EXPECT PANIC!!!\n", &clist); 131 printf("2. Try to free ctx3 (%p): ", &clist2); 132 if(sysctl_ctx_free(&clist2)) { 133 printf("sysctl_ctx_free(%p) failed!\n", &clist2); 134 /* Remove subtree forcefully... */ 135 sysctl_remove_oid(b_root, 1, 1); 136 printf("sysctl_remove_oid(%p) succeeded\n", b_root); 137 } else 138 printf("Ok\n"); 139 printf("3. Try to free ctx1 (%p) again: ", &clist); 140 if(sysctl_ctx_free(&clist)) { 141 printf("sysctl_ctx_free(%p) failed!\n", &clist); 142 /* Remove subtree forcefully... */ 143 sysctl_remove_oid(a_root1, 1, 1); 144 printf("sysctl_remove_oid(%p) succeeded\n", a_root1); 145 } else 146 printf("Ok\n"); 147 printf("4. Try to free ctx2 (%p): ", &clist1); 148 if(sysctl_ctx_free(&clist1)) { 149 printf("sysctl_ctx_free(%p) failed!\n", &clist1); 150 /* Remove subtree forcefully... */ 151 sysctl_remove_oid(a_root, 1, 1); 152 } else 153 printf("Ok\n"); 154 break; 155 default : 156 error = EINVAL; 157 break; 158 } 159 return error; 160} 161 162static moduledata_t mod_data= { 163 "dyn_sysctl", 164 load, 165 0 166}; 167 168DECLARE_MODULE(dyn_sysctl, mod_data, SI_SUB_EXEC, SI_ORDER_ANY); 169