| 1 | /* |
| 2 | * Copyright (c) 1993, David Greenman |
| 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: src/sys/kern/kern_exec.c,v 1.107.2.15 2002/07/30 15:40:46 nectar Exp $ |
| 27 | */ |
| 28 | |
| 29 | #include <sys/param.h> |
| 30 | #include <sys/systm.h> |
| 31 | #include <sys/sysproto.h> |
| 32 | #include <sys/kernel.h> |
| 33 | #include <sys/mount.h> |
| 34 | #include <sys/filedesc.h> |
| 35 | #include <sys/fcntl.h> |
| 36 | #include <sys/acct.h> |
| 37 | #include <sys/exec.h> |
| 38 | #include <sys/imgact.h> |
| 39 | #include <sys/imgact_elf.h> |
| 40 | #include <sys/kern_syscall.h> |
| 41 | #include <sys/wait.h> |
| 42 | #include <sys/malloc.h> |
| 43 | #include <sys/proc.h> |
| 44 | #include <sys/priv.h> |
| 45 | #include <sys/ktrace.h> |
| 46 | #include <sys/signalvar.h> |
| 47 | #include <sys/pioctl.h> |
| 48 | #include <sys/nlookup.h> |
| 49 | #include <sys/sysent.h> |
| 50 | #include <sys/shm.h> |
| 51 | #include <sys/sysctl.h> |
| 52 | #include <sys/vnode.h> |
| 53 | #include <sys/vmmeter.h> |
| 54 | #include <sys/libkern.h> |
| 55 | |
| 56 | #include <cpu/lwbuf.h> |
| 57 | |
| 58 | #include <vm/vm.h> |
| 59 | #include <vm/vm_param.h> |
| 60 | #include <sys/lock.h> |
| 61 | #include <vm/pmap.h> |
| 62 | #include <vm/vm_page.h> |
| 63 | #include <vm/vm_map.h> |
| 64 | #include <vm/vm_kern.h> |
| 65 | #include <vm/vm_extern.h> |
| 66 | #include <vm/vm_object.h> |
| 67 | #include <vm/vnode_pager.h> |
| 68 | #include <vm/vm_pager.h> |
| 69 | |
| 70 | #include <sys/user.h> |
| 71 | #include <sys/reg.h> |
| 72 | |
| 73 | #include <sys/refcount.h> |
| 74 | #include <sys/thread2.h> |
| 75 | #include <sys/mplock2.h> |
| 76 | |
| 77 | MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); |
| 78 | MALLOC_DEFINE(M_EXECARGS, "exec-args", "Exec arguments"); |
| 79 | |
| 80 | static register_t *exec_copyout_strings (struct image_params *); |
| 81 | |
| 82 | /* XXX This should be vm_size_t. */ |
| 83 | static u_long ps_strings = PS_STRINGS; |
| 84 | SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, ""); |
| 85 | |
| 86 | /* XXX This should be vm_size_t. */ |
| 87 | static u_long usrstack = USRSTACK; |
| 88 | SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, ""); |
| 89 | |
| 90 | u_long ps_arg_cache_limit = PAGE_SIZE / 16; |
| 91 | SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, |
| 92 | &ps_arg_cache_limit, 0, ""); |
| 93 | |
| 94 | int ps_argsopen = 1; |
| 95 | SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); |
| 96 | |
| 97 | static int ktrace_suid = 0; |
| 98 | SYSCTL_INT(_kern, OID_AUTO, ktrace_suid, CTLFLAG_RW, &ktrace_suid, 0, ""); |
| 99 | |
| 100 | void print_execve_args(struct image_args *args); |
| 101 | int debug_execve_args = 0; |
| 102 | SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args, |
| 103 | 0, ""); |
| 104 | |
| 105 | /* |
| 106 | * Exec arguments object cache |
| 107 | */ |
| 108 | static struct objcache *exec_objcache; |
| 109 | |
| 110 | static |
| 111 | void |
| 112 | exec_objcache_init(void *arg __unused) |
| 113 | { |
| 114 | int cluster_limit; |
| 115 | size_t limsize; |
| 116 | |
| 117 | /* |
| 118 | * Maximum number of concurrent execs. This can be limiting on |
| 119 | * systems with a lot of cpu cores but it also eats a significant |
| 120 | * amount of memory. |
| 121 | */ |
| 122 | cluster_limit = (ncpus < 16) ? 16 : ncpus; |
| 123 | limsize = kmem_lim_size(); |
| 124 | if (limsize > 7 * 1024) |
| 125 | cluster_limit *= 2; |
| 126 | if (limsize > 15 * 1024) |
| 127 | cluster_limit *= 2; |
| 128 | |
| 129 | exec_objcache = objcache_create_mbacked( |
| 130 | M_EXECARGS, PATH_MAX + ARG_MAX, |
| 131 | cluster_limit, 8, |
| 132 | NULL, NULL, NULL); |
| 133 | } |
| 134 | SYSINIT(exec_objcache, SI_BOOT2_MACHDEP, SI_ORDER_ANY, exec_objcache_init, 0); |
| 135 | |
| 136 | /* |
| 137 | * stackgap_random specifies if the stackgap should have a random size added |
| 138 | * to it. It must be a power of 2. If non-zero, the stack gap will be |
| 139 | * calculated as: ALIGN(karc4random() & (stackgap_random - 1)). |
| 140 | */ |
| 141 | static int stackgap_random = 1024; |
| 142 | static int |
| 143 | sysctl_kern_stackgap(SYSCTL_HANDLER_ARGS) |
| 144 | { |
| 145 | int error, new_val; |
| 146 | new_val = stackgap_random; |
| 147 | error = sysctl_handle_int(oidp, &new_val, 0, req); |
| 148 | if (error != 0 || req->newptr == NULL) |
| 149 | return (error); |
| 150 | if (new_val > 0 && ((new_val > 16 * PAGE_SIZE) || !powerof2(new_val))) |
| 151 | return (EINVAL); |
| 152 | stackgap_random = new_val; |
| 153 | |
| 154 | return(0); |
| 155 | } |
| 156 | |
| 157 | SYSCTL_PROC(_kern, OID_AUTO, stackgap_random, CTLFLAG_RW|CTLTYPE_INT, |
| 158 | 0, 0, sysctl_kern_stackgap, "I", |
| 159 | "Max random stack gap (power of 2), static gap if negative"); |
| 160 | |
| 161 | void |
| 162 | print_execve_args(struct image_args *args) |
| 163 | { |
| 164 | char *cp; |
| 165 | int ndx; |
| 166 | |
| 167 | cp = args->begin_argv; |
| 168 | for (ndx = 0; ndx < args->argc; ndx++) { |
| 169 | kprintf("\targv[%d]: %s\n", ndx, cp); |
| 170 | while (*cp++ != '\0'); |
| 171 | } |
| 172 | for (ndx = 0; ndx < args->envc; ndx++) { |
| 173 | kprintf("\tenvv[%d]: %s\n", ndx, cp); |
| 174 | while (*cp++ != '\0'); |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * Each of the items is a pointer to a `const struct execsw', hence the |
| 180 | * double pointer here. |
| 181 | */ |
| 182 | static const struct execsw **execsw; |
| 183 | |
| 184 | /* |
| 185 | * Replace current vmspace with a new binary. |
| 186 | * Returns 0 on success, > 0 on recoverable error (use as errno). |
| 187 | * Returns -1 on lethal error which demands killing of the current |
| 188 | * process! |
| 189 | */ |
| 190 | int |
| 191 | kern_execve(struct nlookupdata *nd, struct image_args *args) |
| 192 | { |
| 193 | struct thread *td = curthread; |
| 194 | struct lwp *lp = td->td_lwp; |
| 195 | struct proc *p = td->td_proc; |
| 196 | struct vnode *ovp; |
| 197 | register_t *stack_base; |
| 198 | struct pargs *pa; |
| 199 | struct sigacts *ops; |
| 200 | struct sigacts *nps; |
| 201 | int error, len, i; |
| 202 | struct image_params image_params, *imgp; |
| 203 | struct vattr attr; |
| 204 | int (*img_first) (struct image_params *); |
| 205 | |
| 206 | if (debug_execve_args) { |
| 207 | kprintf("%s()\n", __func__); |
| 208 | print_execve_args(args); |
| 209 | } |
| 210 | |
| 211 | KKASSERT(p); |
| 212 | lwkt_gettoken(&p->p_token); |
| 213 | imgp = &image_params; |
| 214 | |
| 215 | /* |
| 216 | * NOTE: P_INEXEC is handled by exec_new_vmspace() now. We make |
| 217 | * no modifications to the process at all until we get there. |
| 218 | * |
| 219 | * Note that multiple threads may be trying to exec at the same |
| 220 | * time. exec_new_vmspace() handles that too. |
| 221 | */ |
| 222 | |
| 223 | /* |
| 224 | * Initialize part of the common data |
| 225 | */ |
| 226 | imgp->proc = p; |
| 227 | imgp->args = args; |
| 228 | imgp->attr = &attr; |
| 229 | imgp->entry_addr = 0; |
| 230 | imgp->resident = 0; |
| 231 | imgp->vmspace_destroyed = 0; |
| 232 | imgp->interpreted = 0; |
| 233 | imgp->interpreter_name[0] = 0; |
| 234 | imgp->auxargs = NULL; |
| 235 | imgp->vp = NULL; |
| 236 | imgp->firstpage = NULL; |
| 237 | imgp->ps_strings = 0; |
| 238 | imgp->execpath = imgp->freepath = NULL; |
| 239 | imgp->execpathp = 0; |
| 240 | imgp->image_header = NULL; |
| 241 | |
| 242 | interpret: |
| 243 | |
| 244 | /* |
| 245 | * Translate the file name to a vnode. Unlock the cache entry to |
| 246 | * improve parallelism for programs exec'd in parallel. |
| 247 | */ |
| 248 | if ((error = nlookup(nd)) != 0) |
| 249 | goto exec_fail; |
| 250 | error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &imgp->vp); |
| 251 | KKASSERT(nd->nl_flags & NLC_NCPISLOCKED); |
| 252 | nd->nl_flags &= ~NLC_NCPISLOCKED; |
| 253 | cache_unlock(&nd->nl_nch); |
| 254 | if (error) |
| 255 | goto exec_fail; |
| 256 | |
| 257 | /* |
| 258 | * Check file permissions (also 'opens' file). |
| 259 | * Include also the top level mount in the check. |
| 260 | */ |
| 261 | error = exec_check_permissions(imgp, nd->nl_nch.mount); |
| 262 | if (error) { |
| 263 | vn_unlock(imgp->vp); |
| 264 | goto exec_fail_dealloc; |
| 265 | } |
| 266 | |
| 267 | error = exec_map_first_page(imgp); |
| 268 | vn_unlock(imgp->vp); |
| 269 | if (error) |
| 270 | goto exec_fail_dealloc; |
| 271 | |
| 272 | imgp->proc->p_osrel = 0; |
| 273 | |
| 274 | if (debug_execve_args && imgp->interpreted) { |
| 275 | kprintf(" target is interpreted -- recursive pass\n"); |
| 276 | kprintf(" interpreter: %s\n", imgp->interpreter_name); |
| 277 | print_execve_args(args); |
| 278 | } |
| 279 | |
| 280 | /* |
| 281 | * If the current process has a special image activator it |
| 282 | * wants to try first, call it. For example, emulating shell |
| 283 | * scripts differently. |
| 284 | */ |
| 285 | error = -1; |
| 286 | if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) |
| 287 | error = img_first(imgp); |
| 288 | |
| 289 | /* |
| 290 | * If the vnode has a registered vmspace, exec the vmspace |
| 291 | */ |
| 292 | if (error == -1 && imgp->vp->v_resident) { |
| 293 | error = exec_resident_imgact(imgp); |
| 294 | } |
| 295 | |
| 296 | /* |
| 297 | * Loop through the list of image activators, calling each one. |
| 298 | * An activator returns -1 if there is no match, 0 on success, |
| 299 | * and an error otherwise. |
| 300 | */ |
| 301 | for (i = 0; error == -1 && execsw[i]; ++i) { |
| 302 | if (execsw[i]->ex_imgact == NULL || |
| 303 | execsw[i]->ex_imgact == img_first) { |
| 304 | continue; |
| 305 | } |
| 306 | error = (*execsw[i]->ex_imgact)(imgp); |
| 307 | } |
| 308 | |
| 309 | if (error) { |
| 310 | if (error == -1) |
| 311 | error = ENOEXEC; |
| 312 | goto exec_fail_dealloc; |
| 313 | } |
| 314 | |
| 315 | /* |
| 316 | * Special interpreter operation, cleanup and loop up to try to |
| 317 | * activate the interpreter. |
| 318 | */ |
| 319 | if (imgp->interpreted) { |
| 320 | exec_unmap_first_page(imgp); |
| 321 | nlookup_done(nd); |
| 322 | vrele(imgp->vp); |
| 323 | imgp->vp = NULL; |
| 324 | error = nlookup_init(nd, imgp->interpreter_name, UIO_SYSSPACE, |
| 325 | NLC_FOLLOW); |
| 326 | if (error) |
| 327 | goto exec_fail; |
| 328 | goto interpret; |
| 329 | } |
| 330 | |
| 331 | /* |
| 332 | * Do the best to calculate the full path to the image file |
| 333 | */ |
| 334 | if (imgp->auxargs != NULL && |
| 335 | ((args->fname != NULL && args->fname[0] == '/') || |
| 336 | vn_fullpath(imgp->proc, |
| 337 | imgp->vp, |
| 338 | &imgp->execpath, |
| 339 | &imgp->freepath, |
| 340 | 0) != 0)) |
| 341 | imgp->execpath = args->fname; |
| 342 | |
| 343 | /* |
| 344 | * Copy out strings (args and env) and initialize stack base |
| 345 | */ |
| 346 | stack_base = exec_copyout_strings(imgp); |
| 347 | p->p_vmspace->vm_minsaddr = (char *)stack_base; |
| 348 | |
| 349 | /* |
| 350 | * If custom stack fixup routine present for this process |
| 351 | * let it do the stack setup. If we are running a resident |
| 352 | * image there is no auxinfo or other image activator context |
| 353 | * so don't try to add fixups to the stack. |
| 354 | * |
| 355 | * Else stuff argument count as first item on stack |
| 356 | */ |
| 357 | if (p->p_sysent->sv_fixup && imgp->resident == 0) |
| 358 | (*p->p_sysent->sv_fixup)(&stack_base, imgp); |
| 359 | else |
| 360 | suword(--stack_base, imgp->args->argc); |
| 361 | |
| 362 | /* |
| 363 | * For security and other reasons, the file descriptor table cannot |
| 364 | * be shared after an exec. |
| 365 | */ |
| 366 | if (p->p_fd->fd_refcnt > 1) { |
| 367 | struct filedesc *tmp; |
| 368 | |
| 369 | error = fdcopy(p, &tmp); |
| 370 | if (error != 0) |
| 371 | goto exec_fail; |
| 372 | fdfree(p, tmp); |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * For security and other reasons, signal handlers cannot |
| 377 | * be shared after an exec. The new proces gets a copy of the old |
| 378 | * handlers. In execsigs(), the new process will have its signals |
| 379 | * reset. |
| 380 | */ |
| 381 | ops = p->p_sigacts; |
| 382 | if (ops->ps_refcnt > 1) { |
| 383 | nps = kmalloc(sizeof(*nps), M_SUBPROC, M_WAITOK); |
| 384 | bcopy(ops, nps, sizeof(*nps)); |
| 385 | refcount_init(&nps->ps_refcnt, 1); |
| 386 | p->p_sigacts = nps; |
| 387 | if (refcount_release(&ops->ps_refcnt)) { |
| 388 | kfree(ops, M_SUBPROC); |
| 389 | ops = NULL; |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | /* |
| 394 | * For security and other reasons virtual kernels cannot be |
| 395 | * inherited by an exec. This also allows a virtual kernel |
| 396 | * to fork/exec unrelated applications. |
| 397 | */ |
| 398 | if (p->p_vkernel) |
| 399 | vkernel_exit(p); |
| 400 | |
| 401 | /* Stop profiling */ |
| 402 | stopprofclock(p); |
| 403 | |
| 404 | /* close files on exec */ |
| 405 | fdcloseexec(p); |
| 406 | |
| 407 | /* reset caught signals */ |
| 408 | execsigs(p); |
| 409 | |
| 410 | /* name this process - nameiexec(p, ndp) */ |
| 411 | len = min(nd->nl_nch.ncp->nc_nlen, MAXCOMLEN); |
| 412 | bcopy(nd->nl_nch.ncp->nc_name, p->p_comm, len); |
| 413 | p->p_comm[len] = 0; |
| 414 | bcopy(p->p_comm, lp->lwp_thread->td_comm, MAXCOMLEN+1); |
| 415 | |
| 416 | /* |
| 417 | * mark as execed, wakeup the process that vforked (if any) and tell |
| 418 | * it that it now has its own resources back |
| 419 | */ |
| 420 | p->p_flags |= P_EXEC; |
| 421 | if (p->p_pptr && (p->p_flags & P_PPWAIT)) { |
| 422 | p->p_flags &= ~P_PPWAIT; |
| 423 | wakeup((caddr_t)p->p_pptr); |
| 424 | } |
| 425 | |
| 426 | /* |
| 427 | * Implement image setuid/setgid. |
| 428 | * |
| 429 | * Don't honor setuid/setgid if the filesystem prohibits it or if |
| 430 | * the process is being traced. |
| 431 | */ |
| 432 | if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) || |
| 433 | ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) && |
| 434 | (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && |
| 435 | (p->p_flags & P_TRACED) == 0) { |
| 436 | /* |
| 437 | * Turn off syscall tracing for set-id programs, except for |
| 438 | * root. Record any set-id flags first to make sure that |
| 439 | * we do not regain any tracing during a possible block. |
| 440 | */ |
| 441 | setsugid(); |
| 442 | if (p->p_tracenode && ktrace_suid == 0 && |
| 443 | priv_check(td, PRIV_ROOT) != 0) { |
| 444 | ktrdestroy(&p->p_tracenode); |
| 445 | p->p_traceflag = 0; |
| 446 | } |
| 447 | /* Close any file descriptors 0..2 that reference procfs */ |
| 448 | setugidsafety(p); |
| 449 | /* Make sure file descriptors 0..2 are in use. */ |
| 450 | error = fdcheckstd(lp); |
| 451 | if (error != 0) |
| 452 | goto exec_fail_dealloc; |
| 453 | /* |
| 454 | * Set the new credentials. |
| 455 | */ |
| 456 | cratom(&p->p_ucred); |
| 457 | if (attr.va_mode & VSUID) |
| 458 | change_euid(attr.va_uid); |
| 459 | if (attr.va_mode & VSGID) |
| 460 | p->p_ucred->cr_gid = attr.va_gid; |
| 461 | |
| 462 | /* |
| 463 | * Clear local varsym variables |
| 464 | */ |
| 465 | varsymset_clean(&p->p_varsymset); |
| 466 | } else { |
| 467 | if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid && |
| 468 | p->p_ucred->cr_gid == p->p_ucred->cr_rgid) |
| 469 | p->p_flags &= ~P_SUGID; |
| 470 | } |
| 471 | |
| 472 | /* |
| 473 | * Implement correct POSIX saved-id behavior. |
| 474 | */ |
| 475 | if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid || |
| 476 | p->p_ucred->cr_svgid != p->p_ucred->cr_gid) { |
| 477 | cratom(&p->p_ucred); |
| 478 | p->p_ucred->cr_svuid = p->p_ucred->cr_uid; |
| 479 | p->p_ucred->cr_svgid = p->p_ucred->cr_gid; |
| 480 | } |
| 481 | |
| 482 | /* |
| 483 | * Store the vp for use in procfs. Be sure to keep p_textvp |
| 484 | * consistent if we block during the switch-over. |
| 485 | */ |
| 486 | ovp = p->p_textvp; |
| 487 | vref(imgp->vp); /* ref new vp */ |
| 488 | p->p_textvp = imgp->vp; |
| 489 | if (ovp) /* release old vp */ |
| 490 | vrele(ovp); |
| 491 | |
| 492 | /* Release old namecache handle to text file */ |
| 493 | if (p->p_textnch.ncp) |
| 494 | cache_drop(&p->p_textnch); |
| 495 | |
| 496 | if (nd->nl_nch.mount) |
| 497 | cache_copy(&nd->nl_nch, &p->p_textnch); |
| 498 | |
| 499 | /* |
| 500 | * Notify others that we exec'd, and clear the P_INEXEC flag |
| 501 | * as we're now a bona fide freshly-execed process. |
| 502 | */ |
| 503 | KNOTE(&p->p_klist, NOTE_EXEC); |
| 504 | p->p_flags &= ~P_INEXEC; |
| 505 | if (p->p_stops) |
| 506 | wakeup(&p->p_stype); |
| 507 | |
| 508 | /* |
| 509 | * If tracing the process, trap to debugger so breakpoints |
| 510 | * can be set before the program executes. |
| 511 | */ |
| 512 | STOPEVENT(p, S_EXEC, 0); |
| 513 | |
| 514 | if (p->p_flags & P_TRACED) |
| 515 | ksignal(p, SIGTRAP); |
| 516 | |
| 517 | /* clear "fork but no exec" flag, as we _are_ execing */ |
| 518 | p->p_acflag &= ~AFORK; |
| 519 | |
| 520 | /* Set values passed into the program in registers. */ |
| 521 | exec_setregs(imgp->entry_addr, (u_long)(uintptr_t)stack_base, |
| 522 | imgp->ps_strings); |
| 523 | |
| 524 | /* Set the access time on the vnode */ |
| 525 | vn_mark_atime(imgp->vp, td); |
| 526 | |
| 527 | /* |
| 528 | * Free any previous argument cache |
| 529 | */ |
| 530 | pa = p->p_args; |
| 531 | p->p_args = NULL; |
| 532 | if (pa && refcount_release(&pa->ar_ref)) { |
| 533 | kfree(pa, M_PARGS); |
| 534 | pa = NULL; |
| 535 | } |
| 536 | |
| 537 | /* |
| 538 | * Cache arguments if they fit inside our allowance |
| 539 | */ |
| 540 | i = imgp->args->begin_envv - imgp->args->begin_argv; |
| 541 | if (sizeof(struct pargs) + i <= ps_arg_cache_limit) { |
| 542 | pa = kmalloc(sizeof(struct pargs) + i, M_PARGS, M_WAITOK); |
| 543 | refcount_init(&pa->ar_ref, 1); |
| 544 | pa->ar_length = i; |
| 545 | bcopy(imgp->args->begin_argv, pa->ar_args, i); |
| 546 | KKASSERT(p->p_args == NULL); |
| 547 | p->p_args = pa; |
| 548 | } |
| 549 | |
| 550 | exec_fail_dealloc: |
| 551 | |
| 552 | /* |
| 553 | * free various allocated resources |
| 554 | */ |
| 555 | if (imgp->firstpage) |
| 556 | exec_unmap_first_page(imgp); |
| 557 | |
| 558 | if (imgp->vp) { |
| 559 | vrele(imgp->vp); |
| 560 | imgp->vp = NULL; |
| 561 | } |
| 562 | |
| 563 | if (imgp->freepath) |
| 564 | kfree(imgp->freepath, M_TEMP); |
| 565 | |
| 566 | if (error == 0) { |
| 567 | ++mycpu->gd_cnt.v_exec; |
| 568 | lwkt_reltoken(&p->p_token); |
| 569 | return (0); |
| 570 | } |
| 571 | |
| 572 | exec_fail: |
| 573 | /* |
| 574 | * we're done here, clear P_INEXEC if we were the ones that |
| 575 | * set it. Otherwise if vmspace_destroyed is still set we |
| 576 | * raced another thread and that thread is responsible for |
| 577 | * clearing it. |
| 578 | */ |
| 579 | if (imgp->vmspace_destroyed & 2) { |
| 580 | p->p_flags &= ~P_INEXEC; |
| 581 | if (p->p_stops) |
| 582 | wakeup(&p->p_stype); |
| 583 | } |
| 584 | lwkt_reltoken(&p->p_token); |
| 585 | if (imgp->vmspace_destroyed) { |
| 586 | /* |
| 587 | * Sorry, no more process anymore. exit gracefully. |
| 588 | * However we can't die right here, because our |
| 589 | * caller might have to clean up, so indicate a |
| 590 | * lethal error by returning -1. |
| 591 | */ |
| 592 | return(-1); |
| 593 | } else { |
| 594 | return(error); |
| 595 | } |
| 596 | } |
| 597 | |
| 598 | /* |
| 599 | * execve() system call. |
| 600 | */ |
| 601 | int |
| 602 | sys_execve(struct execve_args *uap) |
| 603 | { |
| 604 | struct nlookupdata nd; |
| 605 | struct image_args args; |
| 606 | int error; |
| 607 | |
| 608 | bzero(&args, sizeof(args)); |
| 609 | |
| 610 | error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW); |
| 611 | if (error == 0) { |
| 612 | error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE, |
| 613 | uap->argv, uap->envv); |
| 614 | } |
| 615 | if (error == 0) |
| 616 | error = kern_execve(&nd, &args); |
| 617 | nlookup_done(&nd); |
| 618 | exec_free_args(&args); |
| 619 | |
| 620 | if (error < 0) { |
| 621 | /* We hit a lethal error condition. Let's die now. */ |
| 622 | exit1(W_EXITCODE(0, SIGABRT)); |
| 623 | /* NOTREACHED */ |
| 624 | } |
| 625 | |
| 626 | /* |
| 627 | * The syscall result is returned in registers to the new program. |
| 628 | * Linux will register %edx as an atexit function and we must be |
| 629 | * sure to set it to 0. XXX |
| 630 | */ |
| 631 | if (error == 0) |
| 632 | uap->sysmsg_result64 = 0; |
| 633 | |
| 634 | return (error); |
| 635 | } |
| 636 | |
| 637 | int |
| 638 | exec_map_page(struct image_params *imgp, vm_pindex_t pageno, |
| 639 | struct lwbuf **plwb, const char **pdata) |
| 640 | { |
| 641 | int rv; |
| 642 | vm_page_t ma; |
| 643 | vm_page_t m; |
| 644 | vm_object_t object; |
| 645 | |
| 646 | /* |
| 647 | * The file has to be mappable. |
| 648 | */ |
| 649 | if ((object = imgp->vp->v_object) == NULL) |
| 650 | return (EIO); |
| 651 | |
| 652 | if (pageno >= object->size) |
| 653 | return (EIO); |
| 654 | |
| 655 | vm_object_hold(object); |
| 656 | m = vm_page_grab(object, pageno, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); |
| 657 | while ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { |
| 658 | ma = m; |
| 659 | |
| 660 | /* |
| 661 | * get_pages unbusies all the requested pages except the |
| 662 | * primary page (at index 0 in this case). The primary |
| 663 | * page may have been wired during the pagein (e.g. by |
| 664 | * the buffer cache) so vnode_pager_freepage() must be |
| 665 | * used to properly release it. |
| 666 | */ |
| 667 | rv = vm_pager_get_page(object, &ma, 1); |
| 668 | m = vm_page_lookup(object, pageno); |
| 669 | |
| 670 | if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) { |
| 671 | if (m) { |
| 672 | vm_page_protect(m, VM_PROT_NONE); |
| 673 | vnode_pager_freepage(m); |
| 674 | } |
| 675 | vm_object_drop(object); |
| 676 | return EIO; |
| 677 | } |
| 678 | } |
| 679 | vm_page_hold(m); |
| 680 | vm_page_wakeup(m); /* unbusy the page */ |
| 681 | vm_object_drop(object); |
| 682 | |
| 683 | *plwb = lwbuf_alloc(m, *plwb); |
| 684 | *pdata = (void *)lwbuf_kva(*plwb); |
| 685 | |
| 686 | return (0); |
| 687 | } |
| 688 | |
| 689 | /* |
| 690 | * Map the first page of an executable image. |
| 691 | * |
| 692 | * NOTE: If the mapping fails we have to NULL-out firstpage which may |
| 693 | * still be pointing to our supplied lwp structure. |
| 694 | */ |
| 695 | int |
| 696 | exec_map_first_page(struct image_params *imgp) |
| 697 | { |
| 698 | int err; |
| 699 | |
| 700 | if (imgp->firstpage) |
| 701 | exec_unmap_first_page(imgp); |
| 702 | |
| 703 | imgp->firstpage = &imgp->firstpage_cache; |
| 704 | err = exec_map_page(imgp, 0, &imgp->firstpage, &imgp->image_header); |
| 705 | |
| 706 | if (err) { |
| 707 | imgp->firstpage = NULL; |
| 708 | return err; |
| 709 | } |
| 710 | |
| 711 | return 0; |
| 712 | } |
| 713 | |
| 714 | void |
| 715 | exec_unmap_page(struct lwbuf *lwb) |
| 716 | { |
| 717 | vm_page_t m; |
| 718 | |
| 719 | crit_enter(); |
| 720 | if (lwb != NULL) { |
| 721 | m = lwbuf_page(lwb); |
| 722 | lwbuf_free(lwb); |
| 723 | vm_page_unhold(m); |
| 724 | } |
| 725 | crit_exit(); |
| 726 | } |
| 727 | |
| 728 | void |
| 729 | exec_unmap_first_page(struct image_params *imgp) |
| 730 | { |
| 731 | exec_unmap_page(imgp->firstpage); |
| 732 | imgp->firstpage = NULL; |
| 733 | imgp->image_header = NULL; |
| 734 | } |
| 735 | |
| 736 | /* |
| 737 | * Destroy old address space, and allocate a new stack |
| 738 | * The new stack is only SGROWSIZ large because it is grown |
| 739 | * automatically in trap.c. |
| 740 | * |
| 741 | * This is the point of no return. |
| 742 | */ |
| 743 | int |
| 744 | exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy) |
| 745 | { |
| 746 | struct vmspace *vmspace = imgp->proc->p_vmspace; |
| 747 | vm_offset_t stack_addr = USRSTACK - maxssiz; |
| 748 | struct proc *p; |
| 749 | vm_map_t map; |
| 750 | int error; |
| 751 | |
| 752 | /* |
| 753 | * Indicate that we cannot gracefully error out any more, kill |
| 754 | * any other threads present, and set P_INEXEC to indicate that |
| 755 | * we are now messing with the process structure proper. |
| 756 | * |
| 757 | * If killalllwps() races return an error which coupled with |
| 758 | * vmspace_destroyed will cause us to exit. This is what we |
| 759 | * want since another thread is patiently waiting for us to exit |
| 760 | * in that case. |
| 761 | */ |
| 762 | p = curproc; |
| 763 | imgp->vmspace_destroyed = 1; |
| 764 | |
| 765 | if (curthread->td_proc->p_nthreads > 1) { |
| 766 | error = killalllwps(1); |
| 767 | if (error) |
| 768 | return (error); |
| 769 | } |
| 770 | imgp->vmspace_destroyed |= 2; /* we are responsible for P_INEXEC */ |
| 771 | p->p_flags |= P_INEXEC; |
| 772 | |
| 773 | /* |
| 774 | * Tell procfs to release its hold on the process. It |
| 775 | * will return EAGAIN. |
| 776 | */ |
| 777 | if (p->p_stops) |
| 778 | wakeup(&p->p_stype); |
| 779 | |
| 780 | /* |
| 781 | * After setting P_INEXEC wait for any remaining references to |
| 782 | * the process (p) to go away. |
| 783 | * |
| 784 | * In particular, a vfork/exec sequence will replace p->p_vmspace |
| 785 | * and we must interlock anyone trying to access the space (aka |
| 786 | * procfs or sys_process.c calling procfs_domem()). |
| 787 | * |
| 788 | * If P_PPWAIT is set the parent vfork()'d and has a PHOLD() on us. |
| 789 | */ |
| 790 | PSTALL(p, "exec1", ((p->p_flags & P_PPWAIT) ? 1 : 0)); |
| 791 | |
| 792 | /* |
| 793 | * Blow away entire process VM, if address space not shared, |
| 794 | * otherwise, create a new VM space so that other threads are |
| 795 | * not disrupted. If we are execing a resident vmspace we |
| 796 | * create a duplicate of it and remap the stack. |
| 797 | */ |
| 798 | map = &vmspace->vm_map; |
| 799 | if (vmcopy) { |
| 800 | vmspace_exec(imgp->proc, vmcopy); |
| 801 | vmspace = imgp->proc->p_vmspace; |
| 802 | pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK); |
| 803 | map = &vmspace->vm_map; |
| 804 | } else if (vmspace->vm_sysref.refcnt == 1) { |
| 805 | shmexit(vmspace); |
| 806 | pmap_remove_pages(vmspace_pmap(vmspace), |
| 807 | 0, VM_MAX_USER_ADDRESS); |
| 808 | vm_map_remove(map, 0, VM_MAX_USER_ADDRESS); |
| 809 | } else { |
| 810 | vmspace_exec(imgp->proc, NULL); |
| 811 | vmspace = imgp->proc->p_vmspace; |
| 812 | map = &vmspace->vm_map; |
| 813 | } |
| 814 | |
| 815 | /* Allocate a new stack */ |
| 816 | error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz, |
| 817 | 0, VM_PROT_ALL, VM_PROT_ALL, 0); |
| 818 | if (error) |
| 819 | return (error); |
| 820 | |
| 821 | /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the |
| 822 | * VM_STACK case, but they are still used to monitor the size of the |
| 823 | * process stack so we can check the stack rlimit. |
| 824 | */ |
| 825 | vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; |
| 826 | vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz; |
| 827 | |
| 828 | return(0); |
| 829 | } |
| 830 | |
| 831 | /* |
| 832 | * Copy out argument and environment strings from the old process |
| 833 | * address space into the temporary string buffer. |
| 834 | */ |
| 835 | int |
| 836 | exec_copyin_args(struct image_args *args, char *fname, |
| 837 | enum exec_path_segflg segflg, char **argv, char **envv) |
| 838 | { |
| 839 | char *argp, *envp; |
| 840 | int error = 0; |
| 841 | size_t length; |
| 842 | |
| 843 | args->buf = objcache_get(exec_objcache, M_WAITOK); |
| 844 | if (args->buf == NULL) |
| 845 | return (ENOMEM); |
| 846 | args->begin_argv = args->buf; |
| 847 | args->endp = args->begin_argv; |
| 848 | args->space = ARG_MAX; |
| 849 | |
| 850 | args->fname = args->buf + ARG_MAX; |
| 851 | |
| 852 | /* |
| 853 | * Copy the file name. |
| 854 | */ |
| 855 | if (segflg == PATH_SYSSPACE) { |
| 856 | error = copystr(fname, args->fname, PATH_MAX, &length); |
| 857 | } else if (segflg == PATH_USERSPACE) { |
| 858 | error = copyinstr(fname, args->fname, PATH_MAX, &length); |
| 859 | } |
| 860 | |
| 861 | /* |
| 862 | * Extract argument strings. argv may not be NULL. The argv |
| 863 | * array is terminated by a NULL entry. We special-case the |
| 864 | * situation where argv[0] is NULL by passing { filename, NULL } |
| 865 | * to the new program to guarentee that the interpreter knows what |
| 866 | * file to open in case we exec an interpreted file. Note that |
| 867 | * a NULL argv[0] terminates the argv[] array. |
| 868 | * |
| 869 | * XXX the special-casing of argv[0] is historical and needs to be |
| 870 | * revisited. |
| 871 | */ |
| 872 | if (argv == NULL) |
| 873 | error = EFAULT; |
| 874 | if (error == 0) { |
| 875 | while ((argp = (caddr_t)(intptr_t)fuword(argv++)) != NULL) { |
| 876 | if (argp == (caddr_t)-1) { |
| 877 | error = EFAULT; |
| 878 | break; |
| 879 | } |
| 880 | error = copyinstr(argp, args->endp, |
| 881 | args->space, &length); |
| 882 | if (error) { |
| 883 | if (error == ENAMETOOLONG) |
| 884 | error = E2BIG; |
| 885 | break; |
| 886 | } |
| 887 | args->space -= length; |
| 888 | args->endp += length; |
| 889 | args->argc++; |
| 890 | } |
| 891 | if (args->argc == 0 && error == 0) { |
| 892 | length = strlen(args->fname) + 1; |
| 893 | if (length > args->space) { |
| 894 | error = E2BIG; |
| 895 | } else { |
| 896 | bcopy(args->fname, args->endp, length); |
| 897 | args->space -= length; |
| 898 | args->endp += length; |
| 899 | args->argc++; |
| 900 | } |
| 901 | } |
| 902 | } |
| 903 | |
| 904 | args->begin_envv = args->endp; |
| 905 | |
| 906 | /* |
| 907 | * extract environment strings. envv may be NULL. |
| 908 | */ |
| 909 | if (envv && error == 0) { |
| 910 | while ((envp = (caddr_t) (intptr_t) fuword(envv++))) { |
| 911 | if (envp == (caddr_t) -1) { |
| 912 | error = EFAULT; |
| 913 | break; |
| 914 | } |
| 915 | error = copyinstr(envp, args->endp, |
| 916 | args->space, &length); |
| 917 | if (error) { |
| 918 | if (error == ENAMETOOLONG) |
| 919 | error = E2BIG; |
| 920 | break; |
| 921 | } |
| 922 | args->space -= length; |
| 923 | args->endp += length; |
| 924 | args->envc++; |
| 925 | } |
| 926 | } |
| 927 | return (error); |
| 928 | } |
| 929 | |
| 930 | void |
| 931 | exec_free_args(struct image_args *args) |
| 932 | { |
| 933 | if (args->buf) { |
| 934 | objcache_put(exec_objcache, args->buf); |
| 935 | args->buf = NULL; |
| 936 | } |
| 937 | } |
| 938 | |
| 939 | /* |
| 940 | * Copy strings out to the new process address space, constructing |
| 941 | * new arg and env vector tables. Return a pointer to the base |
| 942 | * so that it can be used as the initial stack pointer. |
| 943 | * |
| 944 | * The format is, roughly: |
| 945 | * |
| 946 | * [argv[]] <-- vectp |
| 947 | * [envp[]] |
| 948 | * [ELF_Auxargs] |
| 949 | * |
| 950 | * [args & env] <-- destp |
| 951 | * [sgap] |
| 952 | * [SPARE_USRSPACE] |
| 953 | * [execpath] |
| 954 | * [szsigcode] |
| 955 | * [ps_strings] top of user stack |
| 956 | * |
| 957 | */ |
| 958 | register_t * |
| 959 | exec_copyout_strings(struct image_params *imgp) |
| 960 | { |
| 961 | int argc, envc, sgap; |
| 962 | int gap; |
| 963 | int argsenvspace; |
| 964 | char **vectp; |
| 965 | char *stringp, *destp; |
| 966 | register_t *stack_base; |
| 967 | struct ps_strings *arginfo; |
| 968 | size_t execpath_len; |
| 969 | int szsigcode; |
| 970 | |
| 971 | /* |
| 972 | * Calculate string base and vector table pointers. |
| 973 | * Also deal with signal trampoline code for this exec type. |
| 974 | */ |
| 975 | if (imgp->execpath != NULL && imgp->auxargs != NULL) |
| 976 | execpath_len = strlen(imgp->execpath) + 1; |
| 977 | else |
| 978 | execpath_len = 0; |
| 979 | arginfo = (struct ps_strings *)PS_STRINGS; |
| 980 | szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); |
| 981 | |
| 982 | argsenvspace = roundup((ARG_MAX - imgp->args->space), sizeof(char *)); |
| 983 | gap = stackgap_random; |
| 984 | cpu_ccfence(); |
| 985 | if (gap != 0) { |
| 986 | if (gap < 0) |
| 987 | sgap = ALIGN(-gap); |
| 988 | else |
| 989 | sgap = ALIGN(karc4random() & (gap - 1)); |
| 990 | } else { |
| 991 | sgap = 0; |
| 992 | } |
| 993 | |
| 994 | /* |
| 995 | * Calculate destp, which points to [args & env] and above. |
| 996 | */ |
| 997 | destp = (caddr_t)arginfo - |
| 998 | szsigcode - |
| 999 | roundup(execpath_len, sizeof(char *)) - |
| 1000 | SPARE_USRSPACE - |
| 1001 | sgap - |
| 1002 | argsenvspace; |
| 1003 | |
| 1004 | /* |
| 1005 | * install sigcode |
| 1006 | */ |
| 1007 | if (szsigcode) { |
| 1008 | copyout(imgp->proc->p_sysent->sv_sigcode, |
| 1009 | ((caddr_t)arginfo - szsigcode), szsigcode); |
| 1010 | } |
| 1011 | |
| 1012 | /* |
| 1013 | * Copy the image path for the rtld |
| 1014 | */ |
| 1015 | if (execpath_len) { |
| 1016 | imgp->execpathp = (uintptr_t)arginfo |
| 1017 | - szsigcode |
| 1018 | - roundup(execpath_len, sizeof(char *)); |
| 1019 | copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len); |
| 1020 | } |
| 1021 | |
| 1022 | /* |
| 1023 | * Calculate base for argv[], envp[], and ELF_Auxargs. |
| 1024 | */ |
| 1025 | vectp = (char **)destp - (AT_COUNT * 2); |
| 1026 | vectp -= imgp->args->argc + imgp->args->envc + 2; |
| 1027 | |
| 1028 | stack_base = (register_t *)vectp; |
| 1029 | |
| 1030 | stringp = imgp->args->begin_argv; |
| 1031 | argc = imgp->args->argc; |
| 1032 | envc = imgp->args->envc; |
| 1033 | |
| 1034 | /* |
| 1035 | * Copy out strings - arguments and environment (at destp) |
| 1036 | */ |
| 1037 | copyout(stringp, destp, ARG_MAX - imgp->args->space); |
| 1038 | |
| 1039 | /* |
| 1040 | * Fill in "ps_strings" struct for ps, w, etc. |
| 1041 | */ |
| 1042 | suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); |
| 1043 | suword32(&arginfo->ps_nargvstr, argc); |
| 1044 | |
| 1045 | /* |
| 1046 | * Fill in argument portion of vector table. |
| 1047 | */ |
| 1048 | for (; argc > 0; --argc) { |
| 1049 | suword(vectp++, (long)(intptr_t)destp); |
| 1050 | while (*stringp++ != 0) |
| 1051 | destp++; |
| 1052 | destp++; |
| 1053 | } |
| 1054 | |
| 1055 | /* a null vector table pointer separates the argp's from the envp's */ |
| 1056 | suword(vectp++, 0); |
| 1057 | |
| 1058 | suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); |
| 1059 | suword32(&arginfo->ps_nenvstr, envc); |
| 1060 | |
| 1061 | /* |
| 1062 | * Fill in environment portion of vector table. |
| 1063 | */ |
| 1064 | for (; envc > 0; --envc) { |
| 1065 | suword(vectp++, (long)(intptr_t)destp); |
| 1066 | while (*stringp++ != 0) |
| 1067 | destp++; |
| 1068 | destp++; |
| 1069 | } |
| 1070 | |
| 1071 | /* end of vector table is a null pointer */ |
| 1072 | suword(vectp, 0); |
| 1073 | |
| 1074 | return (stack_base); |
| 1075 | } |
| 1076 | |
| 1077 | /* |
| 1078 | * Check permissions of file to execute. |
| 1079 | * Return 0 for success or error code on failure. |
| 1080 | */ |
| 1081 | int |
| 1082 | exec_check_permissions(struct image_params *imgp, struct mount *topmnt) |
| 1083 | { |
| 1084 | struct proc *p = imgp->proc; |
| 1085 | struct vnode *vp = imgp->vp; |
| 1086 | struct vattr *attr = imgp->attr; |
| 1087 | int error; |
| 1088 | |
| 1089 | /* Get file attributes */ |
| 1090 | error = VOP_GETATTR(vp, attr); |
| 1091 | if (error) |
| 1092 | return (error); |
| 1093 | |
| 1094 | /* |
| 1095 | * 1) Check if file execution is disabled for the filesystem that this |
| 1096 | * file resides on. |
| 1097 | * 2) Insure that at least one execute bit is on - otherwise root |
| 1098 | * will always succeed, and we don't want to happen unless the |
| 1099 | * file really is executable. |
| 1100 | * 3) Insure that the file is a regular file. |
| 1101 | */ |
| 1102 | if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || |
| 1103 | ((topmnt != NULL) && (topmnt->mnt_flag & MNT_NOEXEC)) || |
| 1104 | ((attr->va_mode & 0111) == 0) || |
| 1105 | (attr->va_type != VREG)) { |
| 1106 | return (EACCES); |
| 1107 | } |
| 1108 | |
| 1109 | /* |
| 1110 | * Zero length files can't be exec'd |
| 1111 | */ |
| 1112 | if (attr->va_size == 0) |
| 1113 | return (ENOEXEC); |
| 1114 | |
| 1115 | /* |
| 1116 | * Check for execute permission to file based on current credentials. |
| 1117 | */ |
| 1118 | error = VOP_EACCESS(vp, VEXEC, p->p_ucred); |
| 1119 | if (error) |
| 1120 | return (error); |
| 1121 | |
| 1122 | /* |
| 1123 | * Check number of open-for-writes on the file and deny execution |
| 1124 | * if there are any. |
| 1125 | */ |
| 1126 | if (vp->v_writecount) |
| 1127 | return (ETXTBSY); |
| 1128 | |
| 1129 | /* |
| 1130 | * Call filesystem specific open routine, which allows us to read, |
| 1131 | * write, and mmap the file. Without the VOP_OPEN we can only |
| 1132 | * stat the file. |
| 1133 | */ |
| 1134 | error = VOP_OPEN(vp, FREAD, p->p_ucred, NULL); |
| 1135 | if (error) |
| 1136 | return (error); |
| 1137 | |
| 1138 | return (0); |
| 1139 | } |
| 1140 | |
| 1141 | /* |
| 1142 | * Exec handler registration |
| 1143 | */ |
| 1144 | int |
| 1145 | exec_register(const struct execsw *execsw_arg) |
| 1146 | { |
| 1147 | const struct execsw **es, **xs, **newexecsw; |
| 1148 | int count = 2; /* New slot and trailing NULL */ |
| 1149 | |
| 1150 | if (execsw) |
| 1151 | for (es = execsw; *es; es++) |
| 1152 | count++; |
| 1153 | newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK); |
| 1154 | xs = newexecsw; |
| 1155 | if (execsw) |
| 1156 | for (es = execsw; *es; es++) |
| 1157 | *xs++ = *es; |
| 1158 | *xs++ = execsw_arg; |
| 1159 | *xs = NULL; |
| 1160 | if (execsw) |
| 1161 | kfree(execsw, M_TEMP); |
| 1162 | execsw = newexecsw; |
| 1163 | return 0; |
| 1164 | } |
| 1165 | |
| 1166 | int |
| 1167 | exec_unregister(const struct execsw *execsw_arg) |
| 1168 | { |
| 1169 | const struct execsw **es, **xs, **newexecsw; |
| 1170 | int count = 1; |
| 1171 | |
| 1172 | if (execsw == NULL) |
| 1173 | panic("unregister with no handlers left?"); |
| 1174 | |
| 1175 | for (es = execsw; *es; es++) { |
| 1176 | if (*es == execsw_arg) |
| 1177 | break; |
| 1178 | } |
| 1179 | if (*es == NULL) |
| 1180 | return ENOENT; |
| 1181 | for (es = execsw; *es; es++) |
| 1182 | if (*es != execsw_arg) |
| 1183 | count++; |
| 1184 | newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK); |
| 1185 | xs = newexecsw; |
| 1186 | for (es = execsw; *es; es++) |
| 1187 | if (*es != execsw_arg) |
| 1188 | *xs++ = *es; |
| 1189 | *xs = NULL; |
| 1190 | if (execsw) |
| 1191 | kfree(execsw, M_TEMP); |
| 1192 | execsw = newexecsw; |
| 1193 | return 0; |
| 1194 | } |