sys/kern/lwkt_caps.c

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   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  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/kern/lwkt_caps.c,v 1.6 2005/03/01 23:35:13 dillon Exp $
  35  */
  36
  37 /*
  38  * This module implements the DragonFly LWKT IPC rendezvous and message
  39  * passing API which operates between userland processes, between userland
  40  * threads, and between userland processes and kernel threads.  This API
  41  * is known as the CAPS interface.
  42  *
  43  * Generally speaking this module abstracts the LWKT message port interface
  44  * into userland Clients and Servers rendezvous through ports named
  45  * by or wildcarded by (name,uid,gid).  The kernel provides system calls
  46  * which may be assigned to the mp_* fields in a userland-supplied
  47  * kernel-managed port, and a registration interface which associates an
  48  * upcall with a userland port.  The kernel tracks authentication information
  49  * and deals with connection failures by automatically replying to unreplied
  50  * messages.
  51  *
  52  * From the userland perspective a client/server connection involves two
  53  * message ports on the client and two message ports on the server.
  54  */
  55
  56 #include <sys/param.h>
  57 #include <sys/systm.h>
  58 #include <sys/kernel.h>
  59 #include <sys/sysproto.h>
  60 #include <sys/malloc.h>
  61 #include <sys/proc.h>
  62 #include <sys/ucred.h>
  63 #include <sys/caps.h>
  64 #include <sys/sysctl.h>
  65 #include <vm/vm.h>
  66 #include <vm/vm_extern.h>
  67
  68 static int caps_process_msg(caps_kinfo_t caps, caps_kmsg_t msg, struct caps_sys_get_args *uap);
  69 static void caps_free(caps_kinfo_t caps);
  70 static void caps_free_msg(caps_kmsg_t msg);
  71 static int caps_name_check(const char *name, int len);
  72 static caps_kinfo_t caps_free_msg_mcaps(caps_kmsg_t msg);
  73 static caps_kinfo_t kern_caps_sys_service(const char *name, uid_t uid,
  74                         gid_t gid, struct ucred *cred,
  75                         int flags, int *error);
  76 static caps_kinfo_t kern_caps_sys_client(const char *name, uid_t uid,
  77                         gid_t gid, struct ucred *cred, int flags, int *error);
  78
  79 #define CAPS_HSIZE      64
  80 #define CAPS_HMASK      (CAPS_HSIZE - 1)
  81
  82 static caps_kinfo_t     caps_hash_ary[CAPS_HSIZE];
  83 static int caps_waitsvc;
  84
  85 MALLOC_DEFINE(M_CAPS, "caps", "caps IPC messaging");
  86
  87 static int caps_enabled;
  88 SYSCTL_INT(_kern, OID_AUTO, caps_enabled,
  89         CTLFLAG_RW, &caps_enabled, 0, "Enable CAPS");
  90
  91 /************************************************************************
  92  *                      INLINE SUPPORT FUNCTIONS                        *
  93  ************************************************************************/
  94
  95 static __inline
  96 struct caps_kinfo **
  97 caps_hash(const char *name, int len)
  98 {
  99     int hv = 0x7123F4B3;
 100
 101     while (--len >= 0)
 102         hv = (hv << 5) ^ name[len] ^ (hv >> 23);
 103     return(&caps_hash_ary[(hv ^ (hv >> 16)) & CAPS_HMASK]);
 104 }
 105
 106 static __inline
 107 void
 108 caps_hold(caps_kinfo_t caps)
 109 {
 110     ++caps->ci_refs;
 111 }
 112
 113 static __inline
 114 void
 115 caps_drop(caps_kinfo_t caps)
 116 {
 117     if (--caps->ci_refs == 0)
 118         caps_free(caps);
 119 }
 120
 121 /************************************************************************
 122  *                      STATIC SUPPORT FUNCTIONS                        *
 123  ************************************************************************/
 124
 125 static
 126 caps_kinfo_t
 127 caps_find(const char *name, int len, uid_t uid, gid_t gid)
 128 {
 129     caps_kinfo_t caps;
 130     struct caps_kinfo **chash;
 131
 132     chash = caps_hash(name, len);
 133     for (caps = *chash; caps; caps = caps->ci_hnext) {
 134         if ((uid == (uid_t)-1 || uid == caps->ci_uid) &&
 135             (gid == (gid_t)-1 || gid == caps->ci_gid) &&
 136             len == caps->ci_namelen &&
 137             bcmp(name, caps->ci_name, len) == 0
 138         ) {
 139             caps_hold(caps);
 140             break;
 141         }
 142     }
 143     return(caps);
 144 }
 145
 146 static
 147 caps_kinfo_t
 148 caps_find_id(thread_t td, int id)
 149 {
 150    caps_kinfo_t caps;
 151
 152    for (caps = td->td_caps; caps; caps = caps->ci_tdnext) {
 153         if (caps->ci_id == id) {
 154             caps_hold(caps);
 155             break;
 156         }
 157    }
 158    return(caps);
 159 }
 160
 161 static
 162 caps_kinfo_t
 163 caps_alloc(thread_t td, const char *name, int len, uid_t uid, gid_t gid,
 164             int flags, caps_type_t type)
 165 {
 166     struct caps_kinfo **chash;
 167     caps_kinfo_t caps;
 168     caps_kinfo_t ctmp;
 169
 170     caps = malloc(offsetof(struct caps_kinfo, ci_name[len+1]),
 171                         M_CAPS, M_WAITOK|M_ZERO);
 172     TAILQ_INIT(&caps->ci_msgpendq);
 173     TAILQ_INIT(&caps->ci_msguserq);
 174     caps->ci_uid = uid;         /* -1 == not registered for uid search */
 175     caps->ci_gid = gid;         /* -1 == not registered for gid search */
 176     caps->ci_type = type;
 177     caps->ci_refs = 1;  /* CAPKF_TDLIST reference */
 178     caps->ci_namelen = len;
 179     caps->ci_flags = flags;
 180     bcopy(name, caps->ci_name, len + 1);
 181     if (type == CAPT_SERVICE) {
 182         chash = caps_hash(caps->ci_name, len);
 183         caps->ci_hnext = *chash;
 184         *chash = caps;
 185         caps->ci_flags |= CAPKF_HLIST;
 186     }
 187     if (td->td_caps) {
 188         caps->ci_id = td->td_caps->ci_id + 1;
 189         if (caps->ci_id < 0) {
 190             /*
 191              * It is virtually impossible for this case to occur.
 192              */
 193             caps->ci_id = 1;
 194             while ((ctmp = caps_find_id(td, caps->ci_id)) != NULL) {
 195                 caps_drop(ctmp);
 196                 ++caps->ci_id;
 197             }
 198         }
 199     } else {
 200         caps->ci_id = 1;
 201     }
 202     caps->ci_flags |= CAPKF_TDLIST;
 203     caps->ci_tdnext = td->td_caps;
 204     caps->ci_td = td;
 205     td->td_caps = caps;
 206     return(caps);
 207 }
 208
 209 static
 210 caps_kmsg_t
 211 caps_alloc_msg(caps_kinfo_t caps)
 212 {
 213     caps_kmsg_t msg;
 214
 215     msg = malloc(sizeof(struct caps_kmsg), M_CAPS, M_WAITOK|M_ZERO);
 216     msg->km_msgid.c_id = (off_t)(uintptr_t)msg;
 217     return(msg);
 218 }
 219
 220 static
 221 caps_kmsg_t
 222 caps_find_msg(caps_kinfo_t caps, off_t msgid)
 223 {
 224     caps_kmsg_t msg;
 225
 226     TAILQ_FOREACH(msg, &caps->ci_msguserq, km_node) {
 227         if (msg->km_msgid.c_id == msgid)
 228             return(msg);
 229     }
 230     TAILQ_FOREACH(msg, &caps->ci_msgpendq, km_node) {
 231         if (msg->km_msgid.c_id == msgid)
 232             return(msg);
 233     }
 234     return(NULL);
 235 }
 236
 237 static
 238 caps_kinfo_t
 239 caps_load_ccr(caps_kinfo_t caps, caps_kmsg_t msg, struct proc *p,
 240                 void *udata, int ubytes)
 241 {
 242     int i;
 243     struct ucred *cr = p->p_ucred;
 244     caps_kinfo_t rcaps;
 245
 246     /*
 247      * replace km_mcaps with new VM state, return the old km_mcaps.  The
 248      * caller is expected to drop the rcaps ref count on return so we do
 249      * not do it ourselves.
 250      */
 251     rcaps = caps_free_msg_mcaps(msg);   /* can be NULL */
 252     caps_hold(caps);
 253     msg->km_mcaps = caps;
 254     xio_init_ubuf(&msg->km_xio, udata, ubytes, XIOF_READ);
 255
 256     msg->km_ccr.pid = p ? p->p_pid : -1;
 257     msg->km_ccr.uid = cr->cr_ruid;
 258     msg->km_ccr.euid = cr->cr_uid;
 259     msg->km_ccr.gid = cr->cr_rgid;
 260     msg->km_ccr.ngroups = MIN(cr->cr_ngroups, CAPS_MAXGROUPS);
 261     for (i = 0; i < msg->km_ccr.ngroups; ++i)
 262         msg->km_ccr.groups[i] = cr->cr_groups[i];
 263     return(rcaps);
 264 }
 265
 266 static void
 267 caps_dequeue_msg(caps_kinfo_t caps, caps_kmsg_t msg)
 268 {
 269     if (msg->km_flags & CAPKMF_ONUSERQ)
 270         TAILQ_REMOVE(&caps->ci_msguserq, msg, km_node);
 271     if (msg->km_flags & CAPKMF_ONPENDQ)
 272         TAILQ_REMOVE(&caps->ci_msgpendq, msg, km_node);
 273     msg->km_flags &= ~(CAPKMF_ONPENDQ|CAPKMF_ONUSERQ);
 274 }
 275
 276 static void
 277 caps_put_msg(caps_kinfo_t caps, caps_kmsg_t msg, caps_msg_state_t state)
 278 {
 279     KKASSERT((msg->km_flags & (CAPKMF_ONUSERQ|CAPKMF_ONPENDQ)) == 0);
 280
 281     msg->km_flags |= CAPKMF_ONPENDQ;
 282     msg->km_flags &= ~CAPKMF_PEEKED;
 283     msg->km_state = state;
 284     TAILQ_INSERT_TAIL(&caps->ci_msgpendq, msg, km_node);
 285
 286     /*
 287      * Instead of waking up the service for both new messages and disposals,
 288      * just wakeup the service for new messages and it will process the
 289      * previous disposal in the same loop, reducing the number of context
 290      * switches required to run an IPC.
 291      */
 292     if (state != CAPMS_DISPOSE)
 293         wakeup(caps);
 294     caps_drop(caps);
 295 }
 296
 297 /*
 298  * caps_free_msg_mcaps()
 299  */
 300 static
 301 caps_kinfo_t
 302 caps_free_msg_mcaps(caps_kmsg_t msg)
 303 {
 304     caps_kinfo_t mcaps;
 305
 306     mcaps = msg->km_mcaps;      /* may be NULL */
 307     msg->km_mcaps = NULL;
 308     if (msg->km_xio.xio_npages)
 309         xio_release(&msg->km_xio);
 310     return(mcaps);
 311 }
 312
 313 /*
 314  * caps_free_msg()
 315  *
 316  * Free a caps placeholder message.  The message must not be on any queues.
 317  */
 318 static void
 319 caps_free_msg(caps_kmsg_t msg)
 320 {
 321     caps_kinfo_t rcaps;
 322
 323     if ((rcaps = caps_free_msg_mcaps(msg)) != NULL)
 324         caps_drop(rcaps);
 325     free(msg, M_CAPS);
 326 }
 327
 328 /*
 329  * Validate the service name
 330  */
 331 static int
 332 caps_name_check(const char *name, int len)
 333 {
 334     int i;
 335     char c;
 336
 337     for (i = len - 1; i >= 0; --i) {
 338         c = name[i];
 339         if (c >= '0' && c <= '9')
 340             continue;
 341         if (c >= 'a' && c <= 'z')
 342             continue;
 343         if (c >= 'A' && c <= 'Z')
 344             continue;
 345         if (c == '_' || c == '.')
 346             continue;
 347         return(EINVAL);
 348     }
 349     return(0);
 350 }
 351
 352 /*
 353  * caps_term()
 354  *
 355  * Terminate portions of a caps info structure.  This is used to close
 356  * an end-point or to flush particular messages on an end-point.
 357  *
 358  * This function should not be called with CAPKF_TDLIST unless the caller
 359  * has an additional hold on the caps structure.
 360  */
 361 static void
 362 caps_term(caps_kinfo_t caps, int flags, caps_kinfo_t cflush)
 363 {
 364     struct caps_kinfo **scan;
 365     caps_kmsg_t msg;
 366
 367     if (flags & CAPKF_TDLIST)
 368         caps->ci_flags |= CAPKF_CLOSED;
 369
 370     if (flags & CAPKF_FLUSH) {
 371         int mflags;
 372         struct caps_kmsg_queue tmpuserq;
 373         struct caps_kmsg_queue tmppendq;
 374         caps_kinfo_t rcaps;
 375
 376         TAILQ_INIT(&tmpuserq);
 377         TAILQ_INIT(&tmppendq);
 378
 379         while ((msg = TAILQ_FIRST(&caps->ci_msgpendq)) != NULL ||
 380                (msg = TAILQ_FIRST(&caps->ci_msguserq)) != NULL
 381         ) {
 382             mflags = msg->km_flags & (CAPKMF_ONUSERQ|CAPKMF_ONPENDQ);
 383             caps_dequeue_msg(caps, msg);
 384
 385             if (cflush && msg->km_mcaps != cflush) {
 386                 if (mflags & CAPKMF_ONUSERQ)
 387                     TAILQ_INSERT_TAIL(&tmpuserq, msg, km_node);
 388                 else
 389                     TAILQ_INSERT_TAIL(&tmppendq, msg, km_node);
 390             } else {
 391                 /*
 392                  * Dispose of the message.  If the received message is a
 393                  * request we must reply it.  If the received message is
 394                  * a reply we must return it for disposal.  If the
 395                  * received message is a disposal request we simply free it.
 396                  */
 397                 switch(msg->km_state) {
 398                 case CAPMS_REQUEST:
 399                 case CAPMS_REQUEST_RETRY:
 400                     rcaps = caps_load_ccr(caps, msg, curproc, NULL, 0);
 401                     if (rcaps->ci_flags & CAPKF_CLOSED) {
 402                         /*
 403                          * can't reply, if we never read the message (its on
 404                          * the pending queue), or if we are closed ourselves,
 405                          * we can just free the message.  Otherwise we have
 406                          * to send ourselves a disposal request (multi-threaded
 407                          * services have to deal with disposal requests for
 408                          * messages that might be in progress).
 409                          */
 410                         if ((caps->ci_flags & CAPKF_CLOSED) ||
 411                             (mflags & CAPKMF_ONPENDQ)
 412                         ) {
 413                             caps_free_msg(msg);
 414                             caps_drop(rcaps);
 415                         } else {
 416                             caps_drop(rcaps);
 417                             caps_hold(caps);    /* for message */
 418                             caps_put_msg(caps, msg, CAPMS_DISPOSE);
 419                         }
 420                     } else {
 421                         /*
 422                          * auto-reply to the originator.  rcaps already
 423                          * has a dangling hold so we do not have to hold it
 424                          * again.
 425                          */
 426                         caps_put_msg(rcaps, msg, CAPMS_REPLY);
 427                     }
 428                     break;
 429                 case CAPMS_REPLY:
 430                 case CAPMS_REPLY_RETRY:
 431                     rcaps = caps_load_ccr(caps, msg, curproc, NULL, 0);
 432                     if (caps == rcaps || (rcaps->ci_flags & CAPKF_CLOSED)) {
 433                         caps_free_msg(msg);     /* degenerate disposal case */
 434                         caps_drop(rcaps);
 435                     } else {
 436                         caps_put_msg(rcaps, msg, CAPMS_DISPOSE);
 437                     }
 438                     break;
 439                 case CAPMS_DISPOSE:
 440                     caps_free_msg(msg);
 441                     break;
 442                 }
 443             }
 444         }
 445         while ((msg = TAILQ_FIRST(&tmpuserq)) != NULL) {
 446             TAILQ_REMOVE(&tmpuserq, msg, km_node);
 447             TAILQ_INSERT_TAIL(&caps->ci_msguserq, msg, km_node);
 448             msg->km_flags |= CAPKMF_ONUSERQ;
 449         }
 450         while ((msg = TAILQ_FIRST(&tmppendq)) != NULL) {
 451             TAILQ_REMOVE(&tmppendq, msg, km_node);
 452             TAILQ_INSERT_TAIL(&caps->ci_msgpendq, msg, km_node);
 453             msg->km_flags |= CAPKMF_ONPENDQ;
 454         }
 455     }
 456     if ((flags & CAPKF_HLIST) && (caps->ci_flags & CAPKF_HLIST)) {
 457         for (scan = caps_hash(caps->ci_name, caps->ci_namelen);
 458             *scan != caps;
 459             scan = &(*scan)->ci_hnext
 460         ) {
 461             KKASSERT(*scan != NULL);
 462         }
 463         *scan = caps->ci_hnext;
 464         caps->ci_hnext = (void *)-1;
 465         caps->ci_flags &= ~CAPKF_HLIST;
 466     }
 467     if ((flags & CAPKF_TDLIST) && (caps->ci_flags & CAPKF_TDLIST)) {
 468         for (scan = &caps->ci_td->td_caps;
 469             *scan != caps;
 470             scan = &(*scan)->ci_tdnext
 471         ) {
 472             KKASSERT(*scan != NULL);
 473         }
 474         *scan = caps->ci_tdnext;
 475         caps->ci_flags &= ~CAPKF_TDLIST;
 476         caps->ci_tdnext = (void *)-1;
 477         caps->ci_td = NULL;
 478         caps_drop(caps);
 479     }
 480     if ((flags & CAPKF_RCAPS) && (caps->ci_flags & CAPKF_RCAPS)) {
 481         caps_kinfo_t ctmp;
 482
 483         caps->ci_flags &= ~CAPKF_RCAPS;
 484         if ((ctmp = caps->ci_rcaps)) {
 485             caps->ci_rcaps = NULL;
 486             caps_term(ctmp, CAPKF_FLUSH, caps);
 487             caps_drop(ctmp);
 488         }
 489     }
 490 }
 491
 492 static void
 493 caps_free(caps_kinfo_t caps)
 494 {
 495     KKASSERT(TAILQ_EMPTY(&caps->ci_msgpendq));
 496     KKASSERT(TAILQ_EMPTY(&caps->ci_msguserq));
 497     KKASSERT((caps->ci_flags & (CAPKF_HLIST|CAPKF_TDLIST)) == 0);
 498     free(caps, M_CAPS);
 499 }
 500
 501 /************************************************************************
 502  *                      PROCESS SUPPORT FUNCTIONS                       *
 503  ************************************************************************/
 504
 505 /*
 506  * Create dummy entries in p2 so we can return the appropriate
 507  * error code.  Robust userland code will check the error for a
 508  * forked condition and reforge the connection.
 509  */
 510 void
 511 caps_fork(struct proc *p1, struct proc *p2, int flags)
 512 {
 513     caps_kinfo_t caps1;
 514     caps_kinfo_t caps2;
 515     thread_t td1;
 516     thread_t td2;
 517
 518     td1 = p1->p_thread;
 519     td2 = p2->p_thread;
 520
 521     /*
 522      * Create dummy entries with the same id's as the originals.  Note
 523      * that service entries are not re-added to the hash table. The
 524      * dummy entries return an ENOTCONN error allowing userland code to
 525      * detect that a fork occured.  Userland must reconnect to the service.
 526      */
 527     for (caps1 = td1->td_caps; caps1; caps1 = caps1->ci_tdnext) {
 528         if (caps1->ci_flags & CAPF_NOFORK)
 529                 continue;
 530         caps2 = caps_alloc(td2,
 531                         caps1->ci_name, caps1->ci_namelen,
 532                         caps1->ci_uid, caps1->ci_gid,
 533                         caps1->ci_flags & CAPF_UFLAGS, CAPT_FORKED);
 534         caps2->ci_id = caps1->ci_id;
 535     }
 536
 537     /*
 538      * Reverse the list order to maintain highest-id-first
 539      */
 540     caps2 = td2->td_caps;
 541     td2->td_caps = NULL;
 542     while (caps2) {
 543         caps1 = caps2->ci_tdnext;
 544         caps2->ci_tdnext = td2->td_caps;
 545         td2->td_caps = caps2;
 546         caps2 = caps1;
 547     }
 548 }
 549
 550 void
 551 caps_exit(struct thread *td)
 552 {
 553     caps_kinfo_t caps;
 554
 555     while ((caps = td->td_caps) != NULL) {
 556         caps_hold(caps);
 557         caps_term(caps, CAPKF_TDLIST|CAPKF_HLIST|CAPKF_FLUSH|CAPKF_RCAPS, NULL);
 558         caps_drop(caps);
 559     }
 560 }
 561
 562 /************************************************************************
 563  *                              SYSTEM CALLS                            *
 564  ************************************************************************/
 565
 566 /*
 567  * caps_sys_service(name, uid, gid, upcid, flags);
 568  *
 569  * Create an IPC service using the specified name, uid, gid, and flags.
 570  * Either uid or gid can be -1, but not both.  The port identifier is
 571  * returned.
 572  *
 573  * upcid can either be an upcall or a kqueue identifier (XXX)
 574  */
 575 int
 576 caps_sys_service(struct caps_sys_service_args *uap)
 577 {
 578     struct ucred *cred = curproc->p_ucred;
 579     char name[CAPS_MAXNAMELEN];
 580     caps_kinfo_t caps;
 581     int len;
 582     int error;
 583
 584     if (caps_enabled == 0)
 585         return(EOPNOTSUPP);
 586     if ((error = copyinstr(uap->name, name, CAPS_MAXNAMELEN, &len)) != 0)
 587         return(error);
 588     if (--len <= 0)
 589         return(EINVAL);
 590     if ((error = caps_name_check(name, len)) != 0)
 591         return(error);
 592
 593     caps = kern_caps_sys_service(name, uap->uid, uap->gid, cred,
 594                                 uap->flags & CAPF_UFLAGS, &error);
 595     if (caps)
 596         uap->sysmsg_result = caps->ci_id;
 597     return(error);
 598 }
 599
 600 /*
 601  * caps_sys_client(name, uid, gid, upcid, flags);
 602  *
 603  * Create an IPC client connected to the specified service.  Either uid or gid
 604  * may be -1, indicating a wildcard, but not both.  The port identifier is
 605  * returned.
 606  *
 607  * upcid can either be an upcall or a kqueue identifier (XXX)
 608  */
 609 int
 610 caps_sys_client(struct caps_sys_client_args *uap)
 611 {
 612     struct ucred *cred = curproc->p_ucred;
 613     char name[CAPS_MAXNAMELEN];
 614     caps_kinfo_t caps;
 615     int len;
 616     int error;
 617
 618     if (caps_enabled == 0)
 619         return(EOPNOTSUPP);
 620     if ((error = copyinstr(uap->name, name, CAPS_MAXNAMELEN, &len)) != 0)
 621         return(error);
 622     if (--len <= 0)
 623         return(EINVAL);
 624     if ((error = caps_name_check(name, len)) != 0)
 625         return(error);
 626
 627     caps = kern_caps_sys_client(name, uap->uid, uap->gid, cred,
 628                                 uap->flags & CAPF_UFLAGS, &error);
 629     if (caps)
 630         uap->sysmsg_result = caps->ci_id;
 631     return(error);
 632 }
 633
 634 int
 635 caps_sys_close(struct caps_sys_close_args *uap)
 636 {
 637     caps_kinfo_t caps;
 638
 639     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 640         return(EINVAL);
 641     caps_term(caps, CAPKF_TDLIST|CAPKF_HLIST|CAPKF_FLUSH|CAPKF_RCAPS, NULL);
 642     caps_drop(caps);
 643     return(0);
 644 }
 645
 646 int
 647 caps_sys_setgen(struct caps_sys_setgen_args *uap)
 648 {
 649     caps_kinfo_t caps;
 650     int error;
 651
 652     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 653         return(EINVAL);
 654     if (caps->ci_type == CAPT_FORKED) {
 655         error = ENOTCONN;
 656     } else {
 657         caps->ci_gen = uap->gen;
 658         error = 0;
 659     }
 660     caps_drop(caps);
 661     return(error);
 662 }
 663
 664 int
 665 caps_sys_getgen(struct caps_sys_getgen_args *uap)
 666 {
 667     caps_kinfo_t caps;
 668     int error;
 669
 670     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 671         return(EINVAL);
 672     if (caps->ci_type == CAPT_FORKED) {
 673         error = ENOTCONN;
 674     } else if (caps->ci_rcaps == NULL) {
 675         error = EINVAL;
 676     } else {
 677         uap->sysmsg_result64 = caps->ci_rcaps->ci_gen;
 678         error = 0;
 679     }
 680     caps_drop(caps);
 681     return(error);
 682 }
 683
 684 /*
 685  * caps_sys_put(portid, msg, msgsize)
 686  *
 687  * Send an opaque message of the specified size to the specified port.  This
 688  * function may only be used with a client port.  The message id is returned.
 689  */
 690 int
 691 caps_sys_put(struct caps_sys_put_args *uap)
 692 {
 693     caps_kinfo_t caps;
 694     caps_kmsg_t msg;
 695     struct proc *p = curproc;
 696     int error;
 697
 698     if (uap->msgsize < 0)
 699         return(EINVAL);
 700     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 701         return(EINVAL);
 702     if (caps->ci_type == CAPT_FORKED) {
 703         error = ENOTCONN;
 704     } else if (caps->ci_rcaps == NULL) {
 705         error = EINVAL;
 706     } else if (caps->ci_cmsgcount > CAPS_MAXINPROG) {
 707         /*
 708          * If this client has queued a large number of messages return
 709          * ENOBUFS.  The client must process some replies before it can
 710          * send new messages.  The server can also throttle a client by
 711          * holding its replies.  XXX allow a server to refuse messages from
 712          * a client.
 713          */
 714         error = ENOBUFS;
 715     } else {
 716         msg = caps_alloc_msg(caps);
 717         uap->sysmsg_offset = msg->km_msgid.c_id;
 718
 719         /*
 720          * If the remote end is closed return ENOTCONN immediately, otherwise
 721          * send it to the remote end.
 722          *
 723          * Note: since this is a new message, caps_load_ccr() returns a remote
 724          * caps of NULL.
 725          */
 726         if (caps->ci_rcaps->ci_flags & CAPKF_CLOSED) {
 727             error = ENOTCONN;
 728             caps_free_msg(msg);
 729         } else {
 730             /*
 731              * new message, load_ccr returns NULL. hold rcaps for put_msg
 732              */
 733             error = 0;
 734             caps_load_ccr(caps, msg, p, uap->msg, uap->msgsize);
 735             caps_hold(caps->ci_rcaps);
 736             ++caps->ci_cmsgcount;
 737             caps_put_msg(caps->ci_rcaps, msg, CAPMS_REQUEST); /* drops rcaps */
 738         }
 739     }
 740     caps_drop(caps);
 741     return(error);
 742 }
 743
 744 /*
 745  * caps_sys_reply(portid, msg, msgsize, msgid)
 746  *
 747  * Reply to the message referenced by the specified msgid, supplying opaque
 748  * data back to the originator.
 749  */
 750 int
 751 caps_sys_reply(struct caps_sys_reply_args *uap)
 752 {
 753     caps_kinfo_t caps;
 754     caps_kinfo_t rcaps;
 755     caps_kmsg_t msg;
 756     struct proc *p;
 757     int error;
 758
 759     if (uap->msgsize < 0)
 760         return(EINVAL);
 761     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 762         return(EINVAL);
 763     if (caps->ci_type == CAPT_FORKED) {
 764         /*
 765          * The caps structure is just a fork placeholder, tell the caller
 766          * that he has to reconnect.
 767          */
 768         error = ENOTCONN;
 769     } else if ((msg = caps_find_msg(caps, uap->msgcid)) == NULL) {
 770         /*
 771          * Could not find message being replied to (other side might have
 772          * gone away).
 773          */
 774         error = EINVAL;
 775     } else if ((msg->km_flags & CAPKMF_ONUSERQ) == 0) {
 776         /*
 777          * Trying to reply to a non-replyable message
 778          */
 779         error = EINVAL;
 780     } else {
 781         /*
 782          * If the remote end is closed requeue to ourselves for disposal.
 783          * Otherwise send the reply to the other end (the other end will
 784          * return a passive DISPOSE to us when it has eaten the data)
 785          */
 786         error = 0;
 787         caps_dequeue_msg(caps, msg);
 788         p = curproc;
 789         if (msg->km_mcaps->ci_flags & CAPKF_CLOSED) {
 790             caps_drop(caps_load_ccr(caps, msg, p, NULL, 0));
 791             caps_hold(caps);                    /* ref for message */
 792             caps_put_msg(caps, msg, CAPMS_DISPOSE);
 793         } else {
 794             rcaps = caps_load_ccr(caps, msg, p, uap->msg, uap->msgsize);
 795             caps_put_msg(rcaps, msg, CAPMS_REPLY);
 796         }
 797     }
 798     caps_drop(caps);
 799     return(error);
 800 }
 801
 802 /*
 803  * caps_sys_get(portid, msg, maxsize, msgid, ccr)
 804  *
 805  * Retrieve the next ready message on the port, store its message id in
 806  * uap->msgid and return the length of the message.  If the message is too
 807  * large to fit the message id, length, and creds are still returned, but
 808  * the message is not dequeued (the caller is expected to call again with
 809  * a larger buffer or to reply the messageid if it does not want to handle
 810  * the message).
 811  *
 812  * EWOULDBLOCK is returned if no messages are pending.  Note that 0-length
 813  * messages are perfectly acceptable so 0 can be legitimately returned.
 814  */
 815 int
 816 caps_sys_get(struct caps_sys_get_args *uap)
 817 {
 818     caps_kinfo_t caps;
 819     caps_kmsg_t msg;
 820     int error;
 821
 822     if (uap->maxsize < 0)
 823         return(EINVAL);
 824     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 825         return(EINVAL);
 826     if (caps->ci_type == CAPT_FORKED) {
 827         error = ENOTCONN;
 828     } else if ((msg = TAILQ_FIRST(&caps->ci_msgpendq)) == NULL) {
 829         error = EWOULDBLOCK;
 830     } else {
 831         error = caps_process_msg(caps, msg, uap);
 832     }
 833     caps_drop(caps);
 834     return(error);
 835 }
 836
 837 /*
 838  * caps_sys_wait(portid, msg, maxsize, msgid, ccr)
 839  *
 840  * Retrieve the next ready message on the port, store its message id in
 841  * uap->msgid and return the length of the message.  If the message is too
 842  * large to fit the message id, length, and creds are still returned, but
 843  * the message is not dequeued (the caller is expected to call again with
 844  * a larger buffer or to reply the messageid if it does not want to handle
 845  * the message).
 846  *
 847  * This function blocks until interrupted or a message is received.
 848  * Note that 0-length messages are perfectly acceptable so 0 can be
 849  * legitimately returned.
 850  */
 851 int
 852 caps_sys_wait(struct caps_sys_wait_args *uap)
 853 {
 854     caps_kinfo_t caps;
 855     caps_kmsg_t msg;
 856     int error;
 857
 858     if (uap->maxsize < 0)
 859         return(EINVAL);
 860     if ((caps = caps_find_id(curthread, uap->portid)) == NULL)
 861         return(EINVAL);
 862     if (caps->ci_type == CAPT_FORKED) {
 863         error = ENOTCONN;
 864     } else {
 865         error = 0;
 866         while ((msg = TAILQ_FIRST(&caps->ci_msgpendq)) == NULL) {
 867             if ((error = tsleep(caps, PCATCH, "caps", 0)) != 0)
 868                 break;
 869         }
 870         if (error == 0) {
 871             error = caps_process_msg(caps, msg,
 872                                 (struct caps_sys_get_args *)uap);
 873         }
 874     }
 875     caps_drop(caps);
 876     return(error);
 877 }
 878
 879 static int
 880 caps_process_msg(caps_kinfo_t caps, caps_kmsg_t msg, struct caps_sys_get_args *uap)
 881 {
 882     int error = 0;
 883     int msgsize;
 884     caps_kinfo_t rcaps;
 885
 886     msg->km_flags |= CAPKMF_PEEKED;
 887     msgsize = msg->km_xio.xio_bytes;
 888     if (msgsize <= uap->maxsize)
 889         caps_dequeue_msg(caps, msg);
 890
 891     if (msg->km_xio.xio_bytes != 0) {
 892         error = xio_copy_xtou(&msg->km_xio, 0, uap->msg,
 893                             min(msg->km_xio.xio_bytes, uap->maxsize));
 894         if (error) {
 895             if (msg->km_mcaps->ci_td && msg->km_mcaps->ci_td->td_proc) {
 896                 printf("xio_copy_xtou: error %d from proc %d\n",
 897                         error, msg->km_mcaps->ci_td->td_proc->p_pid);
 898             }
 899             if (msgsize > uap->maxsize)
 900                 caps_dequeue_msg(caps, msg);
 901             msgsize = 0;
 902             error = 0;
 903         }
 904     }
 905
 906     if (uap->msgid)
 907         error = copyout(&msg->km_msgid, uap->msgid, sizeof(msg->km_msgid));
 908     if (uap->ccr)
 909         error = copyout(&msg->km_ccr, uap->ccr, sizeof(msg->km_ccr));
 910     if (error == 0)
 911         uap->sysmsg_result = msgsize;
 912
 913     /*
 914      * If the message was dequeued we must deal with it.
 915      */
 916     if (msgsize <= uap->maxsize) {
 917         switch(msg->km_state) {
 918         case CAPMS_REQUEST:
 919         case CAPMS_REQUEST_RETRY:
 920             TAILQ_INSERT_TAIL(&caps->ci_msguserq, msg, km_node);
 921             msg->km_flags |= CAPKMF_ONUSERQ;
 922             break;
 923         case CAPMS_REPLY:
 924         case CAPMS_REPLY_RETRY:
 925             --caps->ci_cmsgcount;
 926             rcaps = caps_load_ccr(caps, msg, curproc, NULL, 0);
 927             if (caps == rcaps || (rcaps->ci_flags & CAPKF_CLOSED)) {
 928                 /* degenerate disposal case */
 929                 caps_free_msg(msg);
 930                 caps_drop(rcaps);
 931             } else {
 932                 caps_put_msg(rcaps, msg, CAPMS_DISPOSE);
 933             }
 934             break;
 935         case CAPMS_DISPOSE:
 936             caps_free_msg(msg);
 937             break;
 938         }
 939     }
 940     return(error);
 941 }
 942
 943 /*
 944  * caps_sys_abort(portid, msgcid, flags)
 945  *
 946  *      Abort a previously sent message.  You must still wait for the message
 947  *      to be returned after sending the abort request.  This function will
 948  *      return the appropriate CAPS_ABORT_* code depending on what it had
 949  *      to do.
 950  */
 951 int
 952 caps_sys_abort(struct caps_sys_abort_args *uap)
 953 {
 954     uap->sysmsg_result = CAPS_ABORT_NOTIMPL;
 955     return(0);
 956 }
 957
 958 /*
 959  * KERNEL SYSCALL SEPARATION SUPPORT FUNCTIONS
 960  */
 961
 962 static
 963 caps_kinfo_t
 964 kern_caps_sys_service(const char *name, uid_t uid, gid_t gid,
 965                         struct ucred *cred, int flags, int *error)
 966 {
 967     caps_kinfo_t caps;
 968     int len;
 969
 970     len = strlen(name);
 971
 972     /*
 973      * Make sure we can use the uid and gid
 974      */
 975     if (cred) {
 976         if (cred->cr_uid != 0 && uid != (uid_t)-1 && cred->cr_uid != uid) {
 977             *error = EPERM;
 978             return(NULL);
 979         }
 980         if (cred->cr_uid != 0 && gid != (gid_t)-1 && !groupmember(gid, cred)) {
 981             *error = EPERM;
 982             return(NULL);
 983         }
 984     }
 985
 986     /*
 987      * Handle CAPF_EXCL
 988      */
 989     if (flags & CAPF_EXCL) {
 990         if ((caps = caps_find(name, strlen(name), uid, gid)) != NULL) {
 991             caps_drop(caps);
 992             *error = EEXIST;
 993             return(NULL);
 994         }
 995     }
 996
 997     /*
 998      * Create the service
 999      */
1000     caps = caps_alloc(curthread, name, len,
1001                         uid, gid, flags & CAPF_UFLAGS, CAPT_SERVICE);
1002     wakeup(&caps_waitsvc);
1003     return(caps);
1004 }
1005
1006 static
1007 caps_kinfo_t
1008 kern_caps_sys_client(const char *name, uid_t uid, gid_t gid,
1009                         struct ucred *cred, int flags, int *error)
1010 {
1011     caps_kinfo_t caps, rcaps;
1012     int len;
1013
1014     len = strlen(name);
1015
1016     /*
1017      * Locate the CAPS service (rcaps ref is for caps->ci_rcaps)
1018      */
1019 again:
1020     if ((rcaps = caps_find(name, len, uid, gid)) == NULL) {
1021         if (flags & CAPF_WAITSVC) {
1022             char cbuf[32];
1023             snprintf(cbuf, sizeof(cbuf), "C%s", name);
1024             *error = tsleep(&caps_waitsvc, PCATCH, cbuf, 0);
1025             if (*error == 0)
1026                 goto again;
1027         } else {
1028             *error = ENOENT;
1029         }
1030         return(NULL);
1031     }
1032
1033     /*
1034      * Check permissions
1035      */
1036     if (cred) {
1037         *error = EACCES;
1038         if ((flags & CAPF_USER) && (rcaps->ci_flags & CAPF_USER)) {
1039             if (rcaps->ci_uid != (uid_t)-1 && rcaps->ci_uid == cred->cr_uid)
1040                 *error = 0;
1041         }
1042         if ((flags & CAPF_GROUP) && (rcaps->ci_flags & CAPF_GROUP)) {
1043             if (rcaps->ci_gid != (gid_t)-1 && groupmember(rcaps->ci_gid, cred))
1044                 *error = 0;
1045         }
1046         if ((flags & CAPF_WORLD) && (rcaps->ci_flags & CAPF_WORLD)) {
1047             *error = 0;
1048         }
1049         if (*error) {
1050             caps_drop(rcaps);
1051             return(NULL);
1052         }
1053     } else {
1054         *error = 0;
1055     }
1056
1057     /*
1058      * Allocate the client side and connect to the server
1059      */
1060     caps = caps_alloc(curthread, name, len,
1061                         uid, gid, flags & CAPF_UFLAGS, CAPT_CLIENT);
1062     caps->ci_rcaps = rcaps;
1063     caps->ci_flags |= CAPKF_RCAPS;
1064     return(caps);
1065 }
1066