diff options
Diffstat (limited to 'share/examples/kld/dyn_sysctl')
| -rw-r--r-- | share/examples/kld/dyn_sysctl/Makefile | 6 | ||||
| -rw-r--r-- | share/examples/kld/dyn_sysctl/README | 8 | ||||
| -rw-r--r-- | share/examples/kld/dyn_sysctl/dyn_sysctl.c | 168 |
3 files changed, 182 insertions, 0 deletions
diff --git a/share/examples/kld/dyn_sysctl/Makefile b/share/examples/kld/dyn_sysctl/Makefile new file mode 100644 index 000000000000..695320de6080 --- /dev/null +++ b/share/examples/kld/dyn_sysctl/Makefile @@ -0,0 +1,6 @@ +# $FreeBSD$ + +SRCS = dyn_sysctl.c +KMOD = dyn_sysctl + +.include <bsd.kmod.mk> diff --git a/share/examples/kld/dyn_sysctl/README b/share/examples/kld/dyn_sysctl/README new file mode 100644 index 000000000000..4dfa3c6bdfbd --- /dev/null +++ b/share/examples/kld/dyn_sysctl/README @@ -0,0 +1,8 @@ +This example module creates partially overlapping subtrees to demonstrate +reference counting. It also contains example of attaching a subtree to the +wrong place, i.e. to a dynamic oid that could belong to someone else. +The framework should deal with this case gracefully. + +Andrzej Bialecki <abial@freebsd.org> + +$FreeBSD$ diff --git a/share/examples/kld/dyn_sysctl/dyn_sysctl.c b/share/examples/kld/dyn_sysctl/dyn_sysctl.c new file mode 100644 index 000000000000..bcef7d472c5e --- /dev/null +++ b/share/examples/kld/dyn_sysctl/dyn_sysctl.c @@ -0,0 +1,168 @@ +/*- + * Copyright (c) 2000 Andrzej Bialecki <abial@freebsd.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#include <sys/types.h> +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/module.h> +#include <sys/sysctl.h> +#include <sys/kernel.h> + + +/* Some example data */ +static long a = 100; +static int b = 200; +static char *c = "hi there from dyn_sysctl"; +static struct sysctl_oid *a_root, *a_root1, *b_root; +static struct sysctl_ctx_list clist, clist1, clist2; + +static int +sysctl_dyn_sysctl_test (SYSCTL_HANDLER_ARGS) +{ + char *buf = "let's produce some text..."; + + return (sysctl_handle_string(oidp, buf, strlen(buf), req)); +} + +/* + * The function called at load/unload. + */ +static int +load (module_t mod, int cmd, void *arg) +{ + int error; + + error = 0; + switch (cmd) { + case MOD_LOAD : + /* Initialize the contexts */ + printf("Initializing contexts and creating subtrees.\n\n"); + sysctl_ctx_init(&clist); + sysctl_ctx_init(&clist1); + sysctl_ctx_init(&clist2); + /* + * Create two partially overlapping subtrees, belonging + * to different contexts. + */ + printf("TREE ROOT NAME\n"); + a_root = SYSCTL_ADD_NODE(&clist, + SYSCTL_STATIC_CHILDREN(/* top of sysctl tree */), + OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, + "dyn_sysctl root node"); + a_root = SYSCTL_ADD_NODE(&clist1, + SYSCTL_STATIC_CHILDREN(/* top of sysctl tree */), + OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, + "dyn_sysctl root node"); + if(a_root == NULL) { + printf("SYSCTL_ADD_NODE failed!\n"); + return (EINVAL); + } + SYSCTL_ADD_LONG(&clist, SYSCTL_CHILDREN(a_root), + OID_AUTO, "long_a", CTLFLAG_RW, &a, "just to try"); + SYSCTL_ADD_INT(&clist, SYSCTL_CHILDREN(a_root), + OID_AUTO, "int_b", CTLFLAG_RW, &b, 0, "just to try 1"); + a_root1=SYSCTL_ADD_NODE(&clist, SYSCTL_CHILDREN(a_root), + OID_AUTO, "nextlevel", CTLFLAG_RD, 0, "one level down"); + SYSCTL_ADD_STRING(&clist, SYSCTL_CHILDREN(a_root1), + OID_AUTO, "string_c", CTLFLAG_RD, c, 0, "just to try 2"); + printf("1. (%p) / dyn_sysctl\n", &clist); + + /* Add a subtree under already existing category */ + a_root1 = SYSCTL_ADD_NODE(&clist, SYSCTL_STATIC_CHILDREN(_kern), + OID_AUTO, "dyn_sysctl", CTLFLAG_RW, 0, "dyn_sysctl root node"); + if(a_root1 == NULL) { + printf("SYSCTL_ADD_NODE failed!\n"); + return (EINVAL); + } + SYSCTL_ADD_PROC(&clist, SYSCTL_CHILDREN(a_root1), + OID_AUTO, "procedure", CTLFLAG_RD, 0, 0, + sysctl_dyn_sysctl_test, "A", "I can be here, too"); + printf(" (%p) /kern dyn_sysctl\n", &clist); + + /* Overlap second tree with the first. */ + b_root = SYSCTL_ADD_NODE(&clist1, SYSCTL_CHILDREN(a_root), + OID_AUTO, "nextlevel", CTLFLAG_RD, 0, "one level down"); + SYSCTL_ADD_STRING(&clist1, SYSCTL_CHILDREN(b_root), + OID_AUTO, "string_c1", CTLFLAG_RD, c, 0, "just to try 2"); + printf("2. (%p) / dyn_sysctl (overlapping #1)\n", &clist1); + + /* + * And now do something stupid. Connect another subtree to + * dynamic oid. + * WARNING: this is an example of WRONG use of dynamic sysctls. + */ + b_root=SYSCTL_ADD_NODE(&clist2, SYSCTL_CHILDREN(a_root1), + OID_AUTO, "bad", CTLFLAG_RW, 0, "dependent node"); + SYSCTL_ADD_STRING(&clist2, SYSCTL_CHILDREN(b_root), + OID_AUTO, "string_c", CTLFLAG_RD, c, 0, "shouldn't panic"); + printf("3. (%p) /kern/dyn_sysctl bad (WRONG!)\n", &clist2); + break; + case MOD_UNLOAD : + printf("1. Try to free ctx1 (%p): ", &clist); + if(sysctl_ctx_free(&clist)) + printf("failed: expected. Need to remove ctx3 first.\n"); + else + printf("HELP! sysctl_ctx_free(%p) succeeded. EXPECT PANIC!!!\n", &clist); + printf("2. Try to free ctx3 (%p): ", &clist2); + if(sysctl_ctx_free(&clist2)) { + printf("sysctl_ctx_free(%p) failed!\n", &clist2); + /* Remove subtree forcefully... */ + sysctl_remove_oid(b_root, 1, 1); + printf("sysctl_remove_oid(%p) succeeded\n", b_root); + } else + printf("Ok\n"); + printf("3. Try to free ctx1 (%p) again: ", &clist); + if(sysctl_ctx_free(&clist)) { + printf("sysctl_ctx_free(%p) failed!\n", &clist); + /* Remove subtree forcefully... */ + sysctl_remove_oid(a_root1, 1, 1); + printf("sysctl_remove_oid(%p) succeeded\n", a_root1); + } else + printf("Ok\n"); + printf("4. Try to free ctx2 (%p): ", &clist1); + if(sysctl_ctx_free(&clist1)) { + printf("sysctl_ctx_free(%p) failed!\n", &clist1); + /* Remove subtree forcefully... */ + sysctl_remove_oid(a_root, 1, 1); + } else + printf("Ok\n"); + break; + default : + error = EOPNOTSUPP; + break; + } + return error; +} + +static moduledata_t mod_data= { + "dyn_sysctl", + load, + 0 +}; + +DECLARE_MODULE(dyn_sysctl, mod_data, SI_SUB_EXEC, SI_ORDER_ANY); |