/* * Copyright (c) 2000-2013 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ * * * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Mike Karels at Berkeley Software Design, Inc. * * Quite extensively rewritten by Poul-Henning Kamp of the FreeBSD * project, to make these variables more userfriendly. * * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)kern_sysctl.c 8.4 (Berkeley) 4/14/94 */ #include #include #include #include #include #include #include #include #include #include lck_grp_t * sysctl_lock_group = NULL; lck_rw_t * sysctl_geometry_lock = NULL; lck_mtx_t * sysctl_unlocked_node_lock = NULL; /* * Conditionally allow dtrace to see these functions for debugging purposes. */ #ifdef STATIC #undef STATIC #endif #if 0 #define STATIC #else #define STATIC static #endif /* forward declarations of static functions */ STATIC void sysctl_sysctl_debug_dump_node(struct sysctl_oid_list *l, int i); STATIC int sysctl_sysctl_debug(struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req); STATIC int sysctl_sysctl_name(struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req); STATIC int sysctl_sysctl_next_ls (struct sysctl_oid_list *lsp, int *name, u_int namelen, int *next, int *len, int level, struct sysctl_oid **oidpp); STATIC int sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l); STATIC int sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l); STATIC int name2oid (char *name, int *oid, u_int *len); STATIC int sysctl_sysctl_name2oid(struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req); STATIC int sysctl_sysctl_next(struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req); STATIC int sysctl_sysctl_oidfmt(struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req); STATIC int sysctl_old_user(struct sysctl_req *req, const void *p, size_t l); STATIC int sysctl_new_user(struct sysctl_req *req, void *p, size_t l); STATIC void sysctl_create_user_req(struct sysctl_req *req, struct proc *p, user_addr_t oldp, size_t oldlen, user_addr_t newp, size_t newlen); STATIC int sysctl_root(boolean_t from_kernel, boolean_t string_is_canonical, char *namestring, size_t namestringlen, int *name, u_int namelen, struct sysctl_req *req); int kernel_sysctl(struct proc *p, int *name, u_int namelen, void *old, size_t *oldlenp, void *new, size_t newlen); int kernel_sysctlbyname(const char *name, void *oldp, size_t *oldlenp, void *newp, size_t newlen); int userland_sysctl(boolean_t string_is_canonical, char *namestring, size_t namestringlen, int *name, u_int namelen, struct sysctl_req *req, size_t *retval); struct sysctl_oid_list sysctl__children; /* root list */ /* * Initialization of the MIB tree. * * Order by number in each list. */ void sysctl_register_oid(struct sysctl_oid *new_oidp) { struct sysctl_oid *oidp = NULL; struct sysctl_oid_list *parent = new_oidp->oid_parent; struct sysctl_oid *p; struct sysctl_oid *q; int n; /* * The OID can be old-style (needs copy), new style without an earlier * version (also needs copy), or new style with a matching version (no * copy needed). Later versions are rejected (presumably, the OID * structure was changed for a necessary reason). */ if (!(new_oidp->oid_kind & CTLFLAG_OID2)) { /* * XXX: M_TEMP is perhaps not the most apropriate zone, as it * XXX: will subject us to use-after-free by other consumers. */ MALLOC(oidp, struct sysctl_oid *, sizeof(*oidp), M_TEMP, M_WAITOK | M_ZERO); if (oidp == NULL) return; /* reject: no memory */ /* * Copy the structure only through the oid_fmt field, which * is the last field in a non-OID2 OID structure. * * Note: We may want to set the oid_descr to the * oid_name (or "") at some future date. */ memcpy(oidp, new_oidp, offsetof(struct sysctl_oid, oid_descr)); } else { /* It's a later version; handle the versions we know about */ switch (new_oidp->oid_version) { case SYSCTL_OID_VERSION: /* current version */ oidp = new_oidp; break; default: return; /* rejects unknown version */ } } if(sysctl_geometry_lock == NULL) { /* * Initialise the geometry lock for reading/modifying the * sysctl tree. This is done here because IOKit registers * some sysctl's before bsd_init() calls * sysctl_register_fixed(). */ sysctl_lock_group = lck_grp_alloc_init("sysctl", NULL); sysctl_geometry_lock = lck_rw_alloc_init(sysctl_lock_group, NULL); sysctl_unlocked_node_lock = lck_mtx_alloc_init(sysctl_lock_group, NULL); } /* Get the write lock to modify the geometry */ lck_rw_lock_exclusive(sysctl_geometry_lock); /* * If this oid has a number OID_AUTO, give it a number which * is greater than any current oid. Make sure it is at least * OID_AUTO_START to leave space for pre-assigned oid numbers. */ if (oidp->oid_number == OID_AUTO) { /* First, find the highest oid in the parent list >OID_AUTO_START-1 */ n = OID_AUTO_START; SLIST_FOREACH(p, parent, oid_link) { if (p->oid_number > n) n = p->oid_number; } oidp->oid_number = n + 1; /* * Reflect the number in an llocated OID into the template * of the caller for sysctl_unregister_oid() compares. */ if (oidp != new_oidp) new_oidp->oid_number = oidp->oid_number; } /* * Insert the oid into the parent's list in order. */ q = NULL; SLIST_FOREACH(p, parent, oid_link) { if (oidp->oid_number < p->oid_number) break; q = p; } if (q) SLIST_INSERT_AFTER(q, oidp, oid_link); else SLIST_INSERT_HEAD(parent, oidp, oid_link); /* Release the write lock */ lck_rw_unlock_exclusive(sysctl_geometry_lock); } void sysctl_unregister_oid(struct sysctl_oid *oidp) { struct sysctl_oid *removed_oidp = NULL; /* OID removed from tree */ struct sysctl_oid *old_oidp = NULL; /* OID compatibility copy */ /* Get the write lock to modify the geometry */ lck_rw_lock_exclusive(sysctl_geometry_lock); if (!(oidp->oid_kind & CTLFLAG_OID2)) { /* * We're using a copy so we can get the new fields in an * old structure, so we have to iterate to compare the * partial structure; when we find a match, we remove it * normally and free the memory. */ SLIST_FOREACH(old_oidp, oidp->oid_parent, oid_link) { if (!memcmp(&oidp->oid_number, &old_oidp->oid_number, (offsetof(struct sysctl_oid, oid_descr)-offsetof(struct sysctl_oid, oid_number)))) { break; } } if (old_oidp != NULL) { SLIST_REMOVE(old_oidp->oid_parent, old_oidp, sysctl_oid, oid_link); removed_oidp = old_oidp; } } else { /* It's a later version; handle the versions we know about */ switch (oidp->oid_version) { case SYSCTL_OID_VERSION: /* We can just remove the OID directly... */ SLIST_REMOVE(oidp->oid_parent, oidp, sysctl_oid, oid_link); removed_oidp = oidp; break; default: /* XXX: Can't happen; probably tree coruption.*/ break; /* rejects unknown version */ } } /* * We've removed it from the list at this point, but we don't want * to return to the caller until all handler references have drained * out. Doing things in this order prevent other people coming in * and starting new operations against the OID node we want removed. * * Note: oidp could be NULL if it wasn't found. */ while(removed_oidp && removed_oidp->oid_refcnt) { lck_rw_sleep(sysctl_geometry_lock, LCK_SLEEP_EXCLUSIVE, &removed_oidp->oid_refcnt, THREAD_UNINT); } /* Release the write lock */ lck_rw_unlock_exclusive(sysctl_geometry_lock); /* If it was allocated, free it after dropping the lock */ if (old_oidp != NULL) { FREE(old_oidp, M_TEMP); } } /* * Bulk-register all the oids in a linker_set. */ void sysctl_register_set(const char *set) { struct sysctl_oid **oidpp, *oidp; LINKER_SET_FOREACH(oidpp, struct sysctl_oid **, set) { oidp = *oidpp; if (!(oidp->oid_kind & CTLFLAG_NOAUTO)) { sysctl_register_oid(oidp); } } } void sysctl_unregister_set(const char *set) { struct sysctl_oid **oidpp, *oidp; LINKER_SET_FOREACH(oidpp, struct sysctl_oid **, set) { oidp = *oidpp; if (!(oidp->oid_kind & CTLFLAG_NOAUTO)) { sysctl_unregister_oid(oidp); } } } /* * Register the kernel's oids on startup. */ void sysctl_register_all() { sysctl_register_set("__sysctl_set"); } void sysctl_register_fixed(void) { sysctl_register_all(); } /* * New handler interface * If the sysctl caller (user mode or kernel mode) is interested in the * value (req->oldptr != NULL), we copy the data (bigValue etc.) out, * if the caller wants to set the value (req->newptr), we copy * the data in (*pValue etc.). */ int sysctl_io_number(struct sysctl_req *req, long long bigValue, size_t valueSize, void *pValue, int *changed) { int smallValue; int error; if (changed) *changed = 0; /* * Handle the various combinations of caller buffer size and * data value size. We are generous in the case where the * caller has specified a 32-bit buffer but the value is 64-bit * sized. */ /* 32 bit value expected or 32 bit buffer offered */ if (((valueSize == sizeof(int)) || ((req->oldlen == sizeof(int)) && (valueSize == sizeof(long long)))) && (req->oldptr)) { smallValue = (int)bigValue; if ((long long)smallValue != bigValue) return(ERANGE); error = SYSCTL_OUT(req, &smallValue, sizeof(smallValue)); } else { /* any other case is either size-equal or a bug */ error = SYSCTL_OUT(req, &bigValue, valueSize); } /* error or nothing to set */ if (error || !req->newptr) return(error); /* set request for constant */ if (pValue == NULL) return(EPERM); /* set request needs to convert? */ if ((req->newlen == sizeof(int)) && (valueSize == sizeof(long long))) { /* new value is 32 bits, upconvert to 64 bits */ error = SYSCTL_IN(req, &smallValue, sizeof(smallValue)); if (!error) *(long long *)pValue = (long long)smallValue; } else if ((req->newlen == sizeof(long long)) && (valueSize == sizeof(int))) { /* new value is 64 bits, downconvert to 32 bits and range check */ error = SYSCTL_IN(req, &bigValue, sizeof(bigValue)); if (!error) { smallValue = (int)bigValue; if ((long long)smallValue != bigValue) return(ERANGE); *(int *)pValue = smallValue; } } else { /* sizes match, just copy in */ error = SYSCTL_IN(req, pValue, valueSize); } if (!error && changed) *changed = 1; return(error); } int sysctl_io_string(struct sysctl_req *req, char *pValue, size_t valueSize, int trunc, int *changed) { int error; if (changed) *changed = 0; if (trunc && req->oldptr && req->oldlen && (req->oldlenoldlen-1); if (!error) { char c = 0; error = SYSCTL_OUT(req, &c, 1); } } else { /* Copy string out */ error = SYSCTL_OUT(req, pValue, strlen(pValue) + 1); } /* error or no new value */ if (error || !req->newptr) return(error); /* attempt to set read-only value */ if (valueSize == 0) return(EPERM); /* make sure there's room for the new string */ if (req->newlen >= valueSize) return(EINVAL); /* copy the string in and force NUL termination */ error = SYSCTL_IN(req, pValue, req->newlen); pValue[req->newlen] = '\0'; if (!error && changed) *changed = 1; return(error); } int sysctl_io_opaque(struct sysctl_req *req,void *pValue, size_t valueSize, int *changed) { int error; if (changed) *changed = 0; /* Copy blob out */ error = SYSCTL_OUT(req, pValue, valueSize); /* error or nothing to set */ if (error || !req->newptr) return(error); error = SYSCTL_IN(req, pValue, valueSize); if (!error && changed) *changed = 1; return(error); } /* * "Staff-functions" * * These functions implement a presently undocumented interface * used by the sysctl program to walk the tree, and get the type * so it can print the value. * This interface is under work and consideration, and should probably * be killed with a big axe by the first person who can find the time. * (be aware though, that the proper interface isn't as obvious as it * may seem, there are various conflicting requirements. * * {0,0} printf the entire MIB-tree. * {0,1,...} return the name of the "..." OID. * {0,2,...} return the next OID. * {0,3} return the OID of the name in "new" * {0,4,...} return the kind & format info for the "..." OID. */ /* * sysctl_sysctl_debug_dump_node * * Description: Dump debug information for a given sysctl_oid_list at the * given oid depth out to the kernel log, via printf * * Parameters: l sysctl_oid_list pointer * i current node depth * * Returns: (void) * * Implicit: kernel log, modified * * Locks: Assumes sysctl_geometry_lock is held prior to calling * * Notes: This function may call itself recursively to resolve Node * values, which potentially have an inferioer sysctl_oid_list * * This function is only callable indirectly via the function * sysctl_sysctl_debug() * * Bugs: The node depth indentation does not work; this may be an * artifact of leading space removal by the log daemon itself * or some intermediate routine. */ STATIC void sysctl_sysctl_debug_dump_node(struct sysctl_oid_list *l, int i) { int k; struct sysctl_oid *oidp; SLIST_FOREACH(oidp, l, oid_link) { for (k=0; koid_number, oidp->oid_name); printf("%c%c%c", oidp->oid_kind & CTLFLAG_LOCKED ? 'L':' ', oidp->oid_kind & CTLFLAG_RD ? 'R':' ', oidp->oid_kind & CTLFLAG_WR ? 'W':' '); if (oidp->oid_handler) printf(" *Handler"); switch (oidp->oid_kind & CTLTYPE) { case CTLTYPE_NODE: printf(" Node\n"); if (!oidp->oid_handler) { sysctl_sysctl_debug_dump_node( oidp->oid_arg1, i+2); } break; case CTLTYPE_INT: printf(" Int\n"); break; case CTLTYPE_STRING: printf(" String\n"); break; case CTLTYPE_QUAD: printf(" Quad\n"); break; case CTLTYPE_OPAQUE: printf(" Opaque/struct\n"); break; default: printf("\n"); } } } /* * sysctl_sysctl_debug * * Description: This function implements the "sysctl.debug" portion of the * OID space for sysctl. * * OID: 0, 0 * * Parameters: __unused * * Returns: ENOENT * * Implicit: kernel log, modified * * Locks: Acquires and then releases a read lock on the * sysctl_geometry_lock */ STATIC int sysctl_sysctl_debug(__unused struct sysctl_oid *oidp, __unused void *arg1, __unused int arg2, __unused struct sysctl_req *req) { lck_rw_lock_shared(sysctl_geometry_lock); sysctl_sysctl_debug_dump_node(&sysctl__children, 0); lck_rw_done(sysctl_geometry_lock); return ENOENT; } SYSCTL_PROC(_sysctl, 0, debug, CTLTYPE_STRING|CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0, sysctl_sysctl_debug, "-", ""); /* * sysctl_sysctl_name * * Description: Convert an OID into a string name; this is used by the user * space sysctl() command line utility; this is done in a purely * advisory capacity (e.g. to provide node names for "sysctl -A" * output). * * OID: 0, 1 * * Parameters: oidp __unused * arg1 A pointer to the OID name list * integer array, beginning at * adjusted option base 2 * arg2 The number of elements which * remain in the name array * * Returns: 0 Success * SYSCTL_OUT:EPERM Permission denied * SYSCTL_OUT:EFAULT Bad user supplied buffer * SYSCTL_OUT:??? Return value from user function * for SYSCTL_PROC leaf node * * Implict: Contents of user request buffer, modified * * Locks: Acquires and then releases a read lock on the * sysctl_geometry_lock * * Notes: SPI (System Programming Interface); this is subject to change * and may not be relied upon by third party applications; use * a subprocess to communicate with the "sysctl" command line * command instead, if you believe you need this functionality. * Preferrably, use sysctlbyname() instead. * * Setting of the NULL termination of the output string is * delayed until after the geometry lock is dropped. If there * are no Entries remaining in the OID name list when this * function is called, it will still write out the termination * byte. * * This function differs from other sysctl functions in that * it can not take an output buffer length of 0 to determine the * space which will be required. It is suggested that the buffer * length be PATH_MAX, and that authors of new sysctl's refrain * from exceeding this string length. */ STATIC int sysctl_sysctl_name(__unused struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req) { int *name = (int *) arg1; u_int namelen = arg2; int error = 0; struct sysctl_oid *oid; struct sysctl_oid_list *lsp = &sysctl__children, *lsp2; char tempbuf[10]; lck_rw_lock_shared(sysctl_geometry_lock); while (namelen) { if (!lsp) { snprintf(tempbuf,sizeof(tempbuf),"%d",*name); if (req->oldidx) error = SYSCTL_OUT(req, ".", 1); if (!error) error = SYSCTL_OUT(req, tempbuf, strlen(tempbuf)); if (error) { lck_rw_done(sysctl_geometry_lock); return (error); } namelen--; name++; continue; } lsp2 = 0; SLIST_FOREACH(oid, lsp, oid_link) { if (oid->oid_number != *name) continue; if (req->oldidx) error = SYSCTL_OUT(req, ".", 1); if (!error) error = SYSCTL_OUT(req, oid->oid_name, strlen(oid->oid_name)); if (error) { lck_rw_done(sysctl_geometry_lock); return (error); } namelen--; name++; if ((oid->oid_kind & CTLTYPE) != CTLTYPE_NODE) break; if (oid->oid_handler) break; lsp2 = (struct sysctl_oid_list *)oid->oid_arg1; break; } lsp = lsp2; } lck_rw_done(sysctl_geometry_lock); return (SYSCTL_OUT(req, "", 1)); } SYSCTL_NODE(_sysctl, 1, name, CTLFLAG_RD | CTLFLAG_LOCKED, sysctl_sysctl_name, ""); /* * sysctl_sysctl_next_ls * * Description: For a given OID name value, return the next consecutive OID * name value within the geometry tree * * Parameters: lsp The OID list to look in * name The OID name to start from * namelen The length of the OID name * next Pointer to new oid storage to * fill in * len Pointer to receive new OID * length value of storage written * level OID tree depth (used to compute * len value) * oidpp Pointer to OID list entry * pointer; used to walk the list * forward across recursion * * Returns: 0 Returning a new entry * 1 End of geometry list reached * * Implicit: *next Modified to contain the new OID * *len Modified to contain new length * * Locks: Assumes sysctl_geometry_lock is held prior to calling * * Notes: This function will not return OID values that have special * handlers, since we can not tell wheter these handlers consume * elements from the OID space as parameters. For this reason, * we STRONGLY discourage these types of handlers */ STATIC int sysctl_sysctl_next_ls (struct sysctl_oid_list *lsp, int *name, u_int namelen, int *next, int *len, int level, struct sysctl_oid **oidpp) { struct sysctl_oid *oidp; *len = level; SLIST_FOREACH(oidp, lsp, oid_link) { *next = oidp->oid_number; *oidpp = oidp; if (!namelen) { if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) return 0; if (oidp->oid_handler) /* We really should call the handler here...*/ return 0; lsp = (struct sysctl_oid_list *)oidp->oid_arg1; if (!SLIST_FIRST(lsp)) /* This node had no children - skip it! */ continue; if (!sysctl_sysctl_next_ls (lsp, 0, 0, next+1, len, level+1, oidpp)) return 0; goto next; } if (oidp->oid_number < *name) continue; if (oidp->oid_number > *name) { if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) return 0; if (oidp->oid_handler) return 0; lsp = (struct sysctl_oid_list *)oidp->oid_arg1; if (!sysctl_sysctl_next_ls (lsp, name+1, namelen-1, next+1, len, level+1, oidpp)) return (0); goto next; } if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) continue; if (oidp->oid_handler) continue; lsp = (struct sysctl_oid_list *)oidp->oid_arg1; if (!sysctl_sysctl_next_ls (lsp, name+1, namelen-1, next+1, len, level+1, oidpp)) return (0); next: namelen = 1; *len = level; } return 1; } /* * sysctl_sysctl_next * * Description: This is an iterator function designed to iterate the oid tree * and provide a list of OIDs for use by the user space "sysctl" * command line tool * * OID: 0, 2 * * Parameters: oidp __unused * arg1 Pointer to start OID name * arg2 Start OID name length * req Pointer to user request buffer * * Returns: 0 Success * ENOENT Reached end of OID space * SYSCTL_OUT:EPERM Permission denied * SYSCTL_OUT:EFAULT Bad user supplied buffer * SYSCTL_OUT:??? Return value from user function * for SYSCTL_PROC leaf node * * Implict: Contents of user request buffer, modified * * Locks: Acquires and then releases a read lock on the * sysctl_geometry_lock * * Notes: SPI (System Programming Interface); this is subject to change * and may not be relied upon by third party applications; use * a subprocess to communicate with the "sysctl" command line * command instead, if you believe you need this functionality. * Preferrably, use sysctlbyname() instead. * * This function differs from other sysctl functions in that * it can not take an output buffer length of 0 to determine the * space which will be required. It is suggested that the buffer * length be PATH_MAX, and that authors of new sysctl's refrain * from exceeding this string length. */ STATIC int sysctl_sysctl_next(__unused struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req) { int *name = (int *) arg1; u_int namelen = arg2; int i, j, error; struct sysctl_oid *oid; struct sysctl_oid_list *lsp = &sysctl__children; int newoid[CTL_MAXNAME]; lck_rw_lock_shared(sysctl_geometry_lock); i = sysctl_sysctl_next_ls (lsp, name, namelen, newoid, &j, 1, &oid); lck_rw_done(sysctl_geometry_lock); if (i) return ENOENT; error = SYSCTL_OUT(req, newoid, j * sizeof (int)); return (error); } SYSCTL_NODE(_sysctl, 2, next, CTLFLAG_RD | CTLFLAG_LOCKED, sysctl_sysctl_next, ""); /* * name2oid * * Description: Support function for use by sysctl_sysctl_name2oid(); looks * up an OID name given a string name. * * Parameters: name NULL terminated string name * oid Pointer to receive OID name * len Pointer to receive OID length * pointer value (see "Notes") * * Returns: 0 Success * ENOENT Entry not found * * Implicit: *oid Modified to contain OID value * *len Modified to contain OID length * * Locks: Assumes sysctl_geometry_lock is held prior to calling */ STATIC int name2oid (char *name, int *oid, u_int *len) { int i; struct sysctl_oid *oidp; struct sysctl_oid_list *lsp = &sysctl__children; char *p; if (!*name) return ENOENT; p = name + strlen(name) - 1 ; if (*p == '.') *p = '\0'; *len = 0; for (p = name; *p && *p != '.'; p++) ; i = *p; if (i == '.') *p = '\0'; oidp = SLIST_FIRST(lsp); while (oidp && *len < CTL_MAXNAME) { if (strcmp(name, oidp->oid_name)) { oidp = SLIST_NEXT(oidp, oid_link); continue; } *oid++ = oidp->oid_number; (*len)++; if (!i) { return (0); } if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) break; if (oidp->oid_handler) break; lsp = (struct sysctl_oid_list *)oidp->oid_arg1; oidp = SLIST_FIRST(lsp); *p = i; /* restore */ name = p+1; for (p = name; *p && *p != '.'; p++) ; i = *p; if (i == '.') *p = '\0'; } return ENOENT; } /* * sysctl_sysctl_name2oid * * Description: Translate a string name to an OID name value; this is used by * the sysctlbyname() function as well as by the "sysctl" command * line command. * * OID: 0, 3 * * Parameters: oidp __unused * arg1 __unused * arg2 __unused * req Request structure * * Returns: ENOENT Input length too short * ENAMETOOLONG Input length too long * ENOMEM Could not allocate work area * SYSCTL_IN/OUT:EPERM Permission denied * SYSCTL_IN/OUT:EFAULT Bad user supplied buffer * SYSCTL_IN/OUT:??? Return value from user function * name2oid:ENOENT Not found * * Implicit: *req Contents of request, modified * * Locks: Acquires and then releases a read lock on the * sysctl_geometry_lock * * Notes: SPI (System Programming Interface); this is subject to change * and may not be relied upon by third party applications; use * a subprocess to communicate with the "sysctl" command line * command instead, if you believe you need this functionality. * Preferrably, use sysctlbyname() instead. * * This function differs from other sysctl functions in that * it can not take an output buffer length of 0 to determine the * space which will be required. It is suggested that the buffer * length be PATH_MAX, and that authors of new sysctl's refrain * from exceeding this string length. */ STATIC int sysctl_sysctl_name2oid(__unused struct sysctl_oid *oidp, __unused void *arg1, __unused int arg2, struct sysctl_req *req) { char *p; int error, oid[CTL_MAXNAME]; u_int len = 0; /* set by name2oid() */ if (req->newlen < 1) return ENOENT; if (req->newlen >= MAXPATHLEN) /* XXX arbitrary, undocumented */ return (ENAMETOOLONG); MALLOC(p, char *,req->newlen+1, M_TEMP, M_WAITOK); if (!p) return ENOMEM; error = SYSCTL_IN(req, p, req->newlen); if (error) { FREE(p, M_TEMP); return (error); } p [req->newlen] = '\0'; /* * Note: We acquire and release the geometry lock here to * avoid making name2oid needlessly complex. */ lck_rw_lock_shared(sysctl_geometry_lock); error = name2oid(p, oid, &len); lck_rw_done(sysctl_geometry_lock); FREE(p, M_TEMP); if (error) return (error); error = SYSCTL_OUT(req, oid, len * sizeof *oid); return (error); } SYSCTL_PROC(_sysctl, 3, name2oid, CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_KERN | CTLFLAG_LOCKED, 0, 0, sysctl_sysctl_name2oid, "I", ""); /* * sysctl_sysctl_oidfmt * * Description: For a given OID name, determine the format of the data which * is associated with it. This is used by the "sysctl" command * line command. * * OID: 0, 4 * * Parameters: oidp __unused * arg1 The OID name to look up * arg2 The length of the OID name * req Pointer to user request buffer * * Returns: 0 Success * EISDIR Malformed request * ENOENT No such OID name * SYSCTL_OUT:EPERM Permission denied * SYSCTL_OUT:EFAULT Bad user supplied buffer * SYSCTL_OUT:??? Return value from user function * * Implict: Contents of user request buffer, modified * * Locks: Acquires and then releases a read lock on the * sysctl_geometry_lock * * Notes: SPI (System Programming Interface); this is subject to change * and may not be relied upon by third party applications; use * a subprocess to communicate with the "sysctl" command line * command instead, if you believe you need this functionality. * * This function differs from other sysctl functions in that * it can not take an output buffer length of 0 to determine the * space which will be required. It is suggested that the buffer * length be PATH_MAX, and that authors of new sysctl's refrain * from exceeding this string length. */ STATIC int sysctl_sysctl_oidfmt(__unused struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req) { int *name = (int *) arg1; int error = ENOENT; /* default error: not found */ u_int namelen = arg2; u_int indx; struct sysctl_oid *oid; struct sysctl_oid_list *lsp = &sysctl__children; lck_rw_lock_shared(sysctl_geometry_lock); oid = SLIST_FIRST(lsp); indx = 0; while (oid && indx < CTL_MAXNAME) { if (oid->oid_number == name[indx]) { indx++; if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) { if (oid->oid_handler) goto found; if (indx == namelen) goto found; lsp = (struct sysctl_oid_list *)oid->oid_arg1; oid = SLIST_FIRST(lsp); } else { if (indx != namelen) { error = EISDIR; goto err; } goto found; } } else { oid = SLIST_NEXT(oid, oid_link); } } /* Not found */ goto err; found: if (!oid->oid_fmt) goto err; error = SYSCTL_OUT(req, &oid->oid_kind, sizeof(oid->oid_kind)); if (!error) error = SYSCTL_OUT(req, oid->oid_fmt, strlen(oid->oid_fmt)+1); err: lck_rw_done(sysctl_geometry_lock); return (error); } SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD | CTLFLAG_LOCKED, sysctl_sysctl_oidfmt, ""); /* * Default "handler" functions. */ /* * Handle an int, signed or unsigned. * Two cases: * a variable: point arg1 at it. * a constant: pass it in arg2. */ int sysctl_handle_int(__unused struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req) { return sysctl_io_number(req, arg1? *(int*)arg1: arg2, sizeof(int), arg1, NULL); } /* * Handle a long, signed or unsigned. arg1 points to it. */ int sysctl_handle_long(__unused struct sysctl_oid *oidp, void *arg1, __unused int arg2, struct sysctl_req *req) { if (!arg1) return (EINVAL); return sysctl_io_number(req, *(long*)arg1, sizeof(long), arg1, NULL); } /* * Handle a quad, signed or unsigned. arg1 points to it. */ int sysctl_handle_quad(__unused struct sysctl_oid *oidp, void *arg1, __unused int arg2, struct sysctl_req *req) { if (!arg1) return (EINVAL); return sysctl_io_number(req, *(long long*)arg1, sizeof(long long), arg1, NULL); } /* * Expose an int value as a quad. * * This interface allows us to support interfaces defined * as using quad values while the implementation is still * using ints. */ int sysctl_handle_int2quad(__unused struct sysctl_oid *oidp, void *arg1, __unused int arg2, struct sysctl_req *req) { int error = 0; long long val; int newval; if (!arg1) return (EINVAL); val = (long long)*(int *)arg1; error = SYSCTL_OUT(req, &val, sizeof(long long)); if (error || !req->newptr) return (error); error = SYSCTL_IN(req, &val, sizeof(long long)); if (!error) { /* * Value must be representable; check by * casting and then casting back. */ newval = (int)val; if ((long long)newval != val) { error = ERANGE; } else { *(int *)arg1 = newval; } } return (error); } /* * Handle our generic '\0' terminated 'C' string. * Two cases: * a variable string: point arg1 at it, arg2 is max length. * a constant string: point arg1 at it, arg2 is zero. */ int sysctl_handle_string( __unused struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req) { return sysctl_io_string(req, arg1, arg2, 0, NULL); } /* * Handle any kind of opaque data. * arg1 points to it, arg2 is the size. */ int sysctl_handle_opaque(__unused struct sysctl_oid *oidp, void *arg1, int arg2, struct sysctl_req *req) { return sysctl_io_opaque(req, arg1, arg2, NULL); } /* * Transfer functions to/from kernel space. */ STATIC int sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l) { size_t i = 0; if (req->oldptr) { i = l; if (i > req->oldlen - req->oldidx) i = req->oldlen - req->oldidx; if (i > 0) bcopy((const void*)p, CAST_DOWN(char *, (req->oldptr + req->oldidx)), i); } req->oldidx += l; if (req->oldptr && i != l) return (ENOMEM); return (0); } STATIC int sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l) { if (!req->newptr) return 0; if (req->newlen - req->newidx < l) return (EINVAL); bcopy(CAST_DOWN(char *, (req->newptr + req->newidx)), p, l); req->newidx += l; return (0); } int kernel_sysctl(struct proc *p, int *name, u_int namelen, void *old, size_t *oldlenp, void *new, size_t newlen) { int error = 0; struct sysctl_req req; /* * Construct request. */ bzero(&req, sizeof req); req.p = p; if (oldlenp) req.oldlen = *oldlenp; if (old) req.oldptr = CAST_USER_ADDR_T(old); if (newlen) { req.newlen = newlen; req.newptr = CAST_USER_ADDR_T(new); } req.oldfunc = sysctl_old_kernel; req.newfunc = sysctl_new_kernel; req.lock = 1; /* make the request */ error = sysctl_root(TRUE, FALSE, NULL, 0, name, namelen, &req); if (error && error != ENOMEM) return (error); if (oldlenp) *oldlenp = req.oldidx; return (error); } /* * Transfer function to/from user space. */ STATIC int sysctl_old_user(struct sysctl_req *req, const void *p, size_t l) { int error = 0; size_t i = 0; if (req->oldptr) { if (req->oldlen - req->oldidx < l) return (ENOMEM); i = l; if (i > req->oldlen - req->oldidx) i = req->oldlen - req->oldidx; if (i > 0) error = copyout((const void*)p, (req->oldptr + req->oldidx), i); } req->oldidx += l; if (error) return (error); if (req->oldptr && i < l) return (ENOMEM); return (0); } STATIC int sysctl_new_user(struct sysctl_req *req, void *p, size_t l) { int error; if (!req->newptr) return 0; if (req->newlen - req->newidx < l) return (EINVAL); error = copyin((req->newptr + req->newidx), p, l); req->newidx += l; return (error); } /* * Traverse our tree, and find the right node, execute whatever it points * at, and return the resulting error code. */ int sysctl_root(boolean_t from_kernel, boolean_t string_is_canonical, char *namestring, size_t namestringlen, int *name, u_int namelen, struct sysctl_req *req) { u_int indx; int i; struct sysctl_oid *oid; struct sysctl_oid_list *lsp = &sysctl__children; int error; boolean_t unlocked_node_found = FALSE; boolean_t namestring_started = FALSE; /* Get the read lock on the geometry */ lck_rw_lock_shared(sysctl_geometry_lock); if (string_is_canonical) { /* namestring is actually canonical, name/namelen needs to be populated */ error = name2oid(namestring, name, &namelen); if (error) { goto err; } } oid = SLIST_FIRST(lsp); indx = 0; while (oid && indx < CTL_MAXNAME) { if (oid->oid_number == name[indx]) { if (!from_kernel && !string_is_canonical) { if (namestring_started) { if (strlcat(namestring, ".", namestringlen) >= namestringlen) { error = ENAMETOOLONG; goto err; } } if (strlcat(namestring, oid->oid_name, namestringlen) >= namestringlen) { error = ENAMETOOLONG; goto err; } namestring_started = TRUE; } indx++; if (!(oid->oid_kind & CTLFLAG_LOCKED)) { unlocked_node_found = TRUE; } if (oid->oid_kind & CTLFLAG_NOLOCK) req->lock = 0; /* * For SYSCTL_PROC() functions which are for sysctl's * which have parameters at the end of their OID * space, you need to OR CTLTYPE_NODE into their * access value. * * NOTE: For binary backward compatibility ONLY! Do * NOT add new sysctl's that do this! Existing * sysctl's which do this will eventually have * compatibility code in user space, and this method * will become unsupported. */ if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) { if (oid->oid_handler) goto found; if (indx == namelen) { error = ENOENT; goto err; } lsp = (struct sysctl_oid_list *)oid->oid_arg1; oid = SLIST_FIRST(lsp); } else { if (indx != namelen) { error = EISDIR; goto err; } goto found; } } else { oid = SLIST_NEXT(oid, oid_link); } } error = ENOENT; goto err; found: /* * indx is the index of the first remaining OID name, * for sysctls that take them as arguments */ if (!from_kernel && !string_is_canonical && (indx < namelen)) { char tempbuf[10]; u_int indx2; for (indx2 = indx; indx2 < namelen; indx2++) { snprintf(tempbuf, sizeof(tempbuf), "%d",name[indx2]); if (namestring_started) { if (strlcat(namestring, ".", namestringlen) >= namestringlen) { error = ENAMETOOLONG; goto err; } } if (strlcat(namestring, tempbuf, namestringlen) >= namestringlen) { error = ENAMETOOLONG; goto err; } namestring_started = TRUE; } } /* If writing isn't allowed */ if (req->newptr && (!(oid->oid_kind & CTLFLAG_WR) || ((oid->oid_kind & CTLFLAG_SECURE) && securelevel > 0))) { error = (EPERM); goto err; } /* * If we're inside the kernel, the OID must be marked as kernel-valid. */ if (from_kernel && !(oid->oid_kind & CTLFLAG_KERN)) { error = (EPERM); goto err; } /* * This is where legacy enforcement of permissions occurs. If the * flag does not say CTLFLAG_ANYBODY, then we prohibit anyone but * root from writing new values down. If local enforcement happens * at the leaf node, then it needs to be set as CTLFLAG_ANYBODY. In * addition, if the leaf node is set this way, then in order to do * specific enforcement, it has to be of type SYSCTL_PROC. */ if (!(oid->oid_kind & CTLFLAG_ANYBODY) && req->newptr && req->p && (error = proc_suser(req->p))) goto err; if (!oid->oid_handler) { error = EINVAL; goto err; } /* * Reference the OID and drop the geometry lock; this prevents the * OID from being deleted out from under the handler call, but does * not prevent other calls into handlers or calls to manage the * geometry elsewhere from blocking... */ OSAddAtomic(1, &oid->oid_refcnt); lck_rw_done(sysctl_geometry_lock); #if CONFIG_MACF if (!from_kernel) { error = mac_system_check_sysctlbyname(kauth_cred_get(), namestring, name, namelen, req->oldptr, req->oldlen, req->newptr, req->newlen); if (error) goto dropref; } #endif /* * ...however, we still have to grab the mutex for those calls which * may be into code whose reentrancy is protected by it. */ if (unlocked_node_found) { lck_mtx_lock(sysctl_unlocked_node_lock); } if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) { i = (oid->oid_handler) (oid, name + indx, namelen - indx, req); } else { i = (oid->oid_handler) (oid, oid->oid_arg1, oid->oid_arg2, req); } error = i; if (unlocked_node_found) { lck_mtx_unlock(sysctl_unlocked_node_lock); } #if CONFIG_MACF /* only used from another CONFIG_MACF block */ dropref: #endif /* * This is tricky... we re-grab the geometry lock in order to drop * the reference and wake on the address; since the geometry * lock is a reader/writer lock rather than a mutex, we have to * wake on all apparent 1->0 transitions. This abuses the drop * after the reference decrement in order to wake any lck_rw_sleep() * in progress in sysctl_unregister_oid() that slept because of a * non-zero reference count. * * Note: OSAddAtomic() is defined to return the previous value; * we use this and the fact that the lock itself is a * barrier to avoid waking every time through on "hot" * OIDs. */ lck_rw_lock_shared(sysctl_geometry_lock); if (OSAddAtomic(-1, &oid->oid_refcnt) == 1) wakeup(&oid->oid_refcnt); err: lck_rw_done(sysctl_geometry_lock); return (error); } void sysctl_create_user_req(struct sysctl_req *req, struct proc *p, user_addr_t oldp, size_t oldlen, user_addr_t newp, size_t newlen) { bzero(req, sizeof(*req)); req->p = p; req->oldlen = oldlen; req->oldptr = oldp; if (newlen) { req->newlen = newlen; req->newptr = newp; } req->oldfunc = sysctl_old_user; req->newfunc = sysctl_new_user; req->lock = 1; return; } int sysctl(proc_t p, struct sysctl_args *uap, __unused int32_t *retval) { int error; size_t oldlen = 0, newlen; int name[CTL_MAXNAME]; struct sysctl_req req; char *namestring; size_t namestringlen = MAXPATHLEN; /* * all top-level sysctl names are non-terminal */ if (uap->namelen > CTL_MAXNAME || uap->namelen < 2) return (EINVAL); error = copyin(uap->name, &name[0], uap->namelen * sizeof(int)); if (error) return (error); AUDIT_ARG(ctlname, name, uap->namelen); if (uap->newlen > SIZE_T_MAX) return (EINVAL); newlen = (size_t)uap->newlen; if (uap->oldlenp != USER_ADDR_NULL) { uint64_t oldlen64 = fuulong(uap->oldlenp); /* * If more than 4G, clamp to 4G */ if (oldlen64 > SIZE_T_MAX) oldlen = SIZE_T_MAX; else oldlen = (size_t)oldlen64; } sysctl_create_user_req(&req, p, uap->old, oldlen, uap->new, newlen); /* Guess that longest length for the passed-in MIB, if we can be more aggressive than MAXPATHLEN */ if (uap->namelen == 2) { if (name[0] == CTL_KERN && name[1] < KERN_MAXID) { namestringlen = 32; /* "kern.speculative_reads_disabled" */ } else if (name[0] == CTL_HW && name[1] < HW_MAXID) { namestringlen = 32; /* "hw.cachelinesize_compat" */ } } MALLOC(namestring, char *, namestringlen, M_TEMP, M_WAITOK); if (!namestring) { oldlen = 0; goto err; } error = userland_sysctl(FALSE, namestring, namestringlen, name, uap->namelen, &req, &oldlen); FREE(namestring, M_TEMP); if ((error) && (error != ENOMEM)) return (error); err: if (uap->oldlenp != USER_ADDR_NULL) error = suulong(uap->oldlenp, oldlen); return (error); } int sysctlbyname(proc_t p, struct sysctlbyname_args *uap, __unused int32_t *retval) { int error; size_t oldlen = 0, newlen; char *name; size_t namelen = 0; struct sysctl_req req; int oid[CTL_MAXNAME]; if (uap->namelen >= MAXPATHLEN) /* XXX arbitrary, undocumented */ return (ENAMETOOLONG); namelen = (size_t)uap->namelen; MALLOC(name, char *, namelen+1, M_TEMP, M_WAITOK); if (!name) return ENOMEM; error = copyin(uap->name, name, namelen); if (error) { FREE(name, M_TEMP); return (error); } name[namelen] = '\0'; /* XXX * AUDIT_ARG(ctlname, name, uap->namelen); */ if (uap->newlen > SIZE_T_MAX) { FREE(name, M_TEMP); return (EINVAL); } newlen = (size_t)uap->newlen; if (uap->oldlenp != USER_ADDR_NULL) { uint64_t oldlen64 = fuulong(uap->oldlenp); /* * If more than 4G, clamp to 4G */ if (oldlen64 > SIZE_T_MAX) oldlen = SIZE_T_MAX; else oldlen = (size_t)oldlen64; } sysctl_create_user_req(&req, p, uap->old, oldlen, uap->new, newlen); error = userland_sysctl(TRUE, name, namelen+1, oid, CTL_MAXNAME, &req, &oldlen); FREE(name, M_TEMP); if ((error) && (error != ENOMEM)) return (error); if (uap->oldlenp != USER_ADDR_NULL) error = suulong(uap->oldlenp, oldlen); return (error); } /* * This is used from various compatibility syscalls too. That's why name * must be in kernel space. */ int userland_sysctl(boolean_t string_is_canonical, char *namestring, size_t namestringlen, int *name, u_int namelen, struct sysctl_req *req, size_t *retval) { int error = 0; struct sysctl_req req2; do { /* if EAGAIN, reset output cursor */ req2 = *req; if (!string_is_canonical) namestring[0] = '\0'; error = sysctl_root(FALSE, string_is_canonical, namestring, namestringlen, name, namelen, &req2); } while (error == EAGAIN); if (error && error != ENOMEM) return (error); if (retval) { if (req2.oldptr && req2.oldidx > req2.oldlen) *retval = req2.oldlen; else *retval = req2.oldidx; } return (error); } /* * Kernel versions of the userland sysctl helper functions. * * These allow sysctl to be used in the same fashion in both * userland and the kernel. * * Note that some sysctl handlers use copyin/copyout, which * may not work correctly. * * The "sysctlbyname" KPI for use by kexts is aliased to this function. */ int kernel_sysctlbyname(const char *name, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { int oid[CTL_MAXNAME]; int name2mib_oid[2]; int error; size_t oidlen; /* look up the OID with magic service node */ name2mib_oid[0] = 0; name2mib_oid[1] = 3; oidlen = sizeof(oid); error = kernel_sysctl(current_proc(), name2mib_oid, 2, oid, &oidlen, (void *)name, strlen(name)); oidlen /= sizeof(int); /* now use the OID */ if (error == 0) error = kernel_sysctl(current_proc(), oid, oidlen, oldp, oldlenp, newp, newlen); return(error); }