| 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 | * $DragonFly: src/sys/kern/kern_exec.c,v 1.13 2003/11/05 23:26:20 dillon Exp $ |
| 28 | */ |
| 29 | |
| 30 | #include <sys/param.h> |
| 31 | #include <sys/systm.h> |
| 32 | #include <sys/sysproto.h> |
| 33 | #include <sys/kernel.h> |
| 34 | #include <sys/mount.h> |
| 35 | #include <sys/filedesc.h> |
| 36 | #include <sys/fcntl.h> |
| 37 | #include <sys/acct.h> |
| 38 | #include <sys/exec.h> |
| 39 | #include <sys/imgact.h> |
| 40 | #include <sys/imgact_elf.h> |
| 41 | #include <sys/wait.h> |
| 42 | #include <sys/malloc.h> |
| 43 | #include <sys/proc.h> |
| 44 | #include <sys/signalvar.h> |
| 45 | #include <sys/pioctl.h> |
| 46 | #include <sys/namei.h> |
| 47 | #include <sys/sysent.h> |
| 48 | #include <sys/shm.h> |
| 49 | #include <sys/sysctl.h> |
| 50 | #include <sys/vnode.h> |
| 51 | #include <sys/aio.h> |
| 52 | |
| 53 | #include <vm/vm.h> |
| 54 | #include <vm/vm_param.h> |
| 55 | #include <sys/lock.h> |
| 56 | #include <vm/pmap.h> |
| 57 | #include <vm/vm_page.h> |
| 58 | #include <vm/vm_map.h> |
| 59 | #include <vm/vm_kern.h> |
| 60 | #include <vm/vm_extern.h> |
| 61 | #include <vm/vm_object.h> |
| 62 | #include <vm/vm_pager.h> |
| 63 | |
| 64 | #include <sys/user.h> |
| 65 | #include <machine/reg.h> |
| 66 | |
| 67 | MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); |
| 68 | |
| 69 | static register_t *exec_copyout_strings (struct image_params *); |
| 70 | |
| 71 | /* XXX This should be vm_size_t. */ |
| 72 | static u_long ps_strings = PS_STRINGS; |
| 73 | SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, ""); |
| 74 | |
| 75 | /* XXX This should be vm_size_t. */ |
| 76 | static u_long usrstack = USRSTACK; |
| 77 | SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, ""); |
| 78 | |
| 79 | u_long ps_arg_cache_limit = PAGE_SIZE / 16; |
| 80 | SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, |
| 81 | &ps_arg_cache_limit, 0, ""); |
| 82 | |
| 83 | int ps_argsopen = 1; |
| 84 | SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); |
| 85 | |
| 86 | /* |
| 87 | * Each of the items is a pointer to a `const struct execsw', hence the |
| 88 | * double pointer here. |
| 89 | */ |
| 90 | static const struct execsw **execsw; |
| 91 | |
| 92 | /* |
| 93 | * execve() system call. |
| 94 | */ |
| 95 | int |
| 96 | execve(struct execve_args *uap) |
| 97 | { |
| 98 | struct thread *td = curthread; |
| 99 | struct proc *p = td->td_proc; |
| 100 | struct nameidata nd, *ndp; |
| 101 | register_t *stack_base; |
| 102 | int error, len, i; |
| 103 | struct image_params image_params, *imgp; |
| 104 | struct vattr attr; |
| 105 | int (*img_first) (struct image_params *); |
| 106 | |
| 107 | KKASSERT(p); |
| 108 | imgp = &image_params; |
| 109 | |
| 110 | /* |
| 111 | * Lock the process and set the P_INEXEC flag to indicate that |
| 112 | * it should be left alone until we're done here. This is |
| 113 | * necessary to avoid race conditions - e.g. in ptrace() - |
| 114 | * that might allow a local user to illicitly obtain elevated |
| 115 | * privileges. |
| 116 | */ |
| 117 | p->p_flag |= P_INEXEC; |
| 118 | |
| 119 | /* |
| 120 | * Initialize part of the common data |
| 121 | */ |
| 122 | imgp->proc = p; |
| 123 | imgp->uap = uap; |
| 124 | imgp->attr = &attr; |
| 125 | imgp->argc = imgp->envc = 0; |
| 126 | imgp->argv0 = NULL; |
| 127 | imgp->entry_addr = 0; |
| 128 | imgp->vmspace_destroyed = 0; |
| 129 | imgp->interpreted = 0; |
| 130 | imgp->interpreter_name[0] = '\0'; |
| 131 | imgp->auxargs = NULL; |
| 132 | imgp->vp = NULL; |
| 133 | imgp->firstpage = NULL; |
| 134 | imgp->ps_strings = 0; |
| 135 | |
| 136 | /* |
| 137 | * Allocate temporary demand zeroed space for argument and |
| 138 | * environment strings |
| 139 | */ |
| 140 | imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + PAGE_SIZE); |
| 141 | if (imgp->stringbase == NULL) { |
| 142 | error = ENOMEM; |
| 143 | goto exec_fail; |
| 144 | } |
| 145 | imgp->stringp = imgp->stringbase; |
| 146 | imgp->stringspace = ARG_MAX; |
| 147 | imgp->image_header = imgp->stringbase + ARG_MAX; |
| 148 | |
| 149 | /* |
| 150 | * Translate the file name. namei() returns a vnode pointer |
| 151 | * in ni_vp amoung other things. |
| 152 | */ |
| 153 | ndp = &nd; |
| 154 | NDINIT(ndp, NAMEI_LOOKUP, CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME, |
| 155 | UIO_USERSPACE, uap->fname, td); |
| 156 | |
| 157 | interpret: |
| 158 | |
| 159 | error = namei(ndp); |
| 160 | if (error) { |
| 161 | kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, |
| 162 | ARG_MAX + PAGE_SIZE); |
| 163 | goto exec_fail; |
| 164 | } |
| 165 | |
| 166 | imgp->vp = ndp->ni_vp; |
| 167 | imgp->fname = uap->fname; |
| 168 | |
| 169 | /* |
| 170 | * Check file permissions (also 'opens' file) |
| 171 | */ |
| 172 | error = exec_check_permissions(imgp); |
| 173 | if (error) { |
| 174 | VOP_UNLOCK(imgp->vp, 0, td); |
| 175 | goto exec_fail_dealloc; |
| 176 | } |
| 177 | |
| 178 | error = exec_map_first_page(imgp); |
| 179 | VOP_UNLOCK(imgp->vp, 0, td); |
| 180 | if (error) |
| 181 | goto exec_fail_dealloc; |
| 182 | |
| 183 | /* |
| 184 | * If the current process has a special image activator it |
| 185 | * wants to try first, call it. For example, emulating shell |
| 186 | * scripts differently. |
| 187 | */ |
| 188 | error = -1; |
| 189 | if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) |
| 190 | error = img_first(imgp); |
| 191 | |
| 192 | /* |
| 193 | * Loop through the list of image activators, calling each one. |
| 194 | * An activator returns -1 if there is no match, 0 on success, |
| 195 | * and an error otherwise. |
| 196 | */ |
| 197 | for (i = 0; error == -1 && execsw[i]; ++i) { |
| 198 | if (execsw[i]->ex_imgact == NULL || |
| 199 | execsw[i]->ex_imgact == img_first) { |
| 200 | continue; |
| 201 | } |
| 202 | error = (*execsw[i]->ex_imgact)(imgp); |
| 203 | } |
| 204 | |
| 205 | if (error) { |
| 206 | if (error == -1) |
| 207 | error = ENOEXEC; |
| 208 | goto exec_fail_dealloc; |
| 209 | } |
| 210 | |
| 211 | /* |
| 212 | * Special interpreter operation, cleanup and loop up to try to |
| 213 | * activate the interpreter. |
| 214 | */ |
| 215 | if (imgp->interpreted) { |
| 216 | exec_unmap_first_page(imgp); |
| 217 | /* free name buffer and old vnode */ |
| 218 | NDFREE(ndp, NDF_ONLY_PNBUF); |
| 219 | vrele(ndp->ni_vp); |
| 220 | /* set new name to that of the interpreter */ |
| 221 | NDINIT(ndp, NAMEI_LOOKUP, |
| 222 | CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME, |
| 223 | UIO_SYSSPACE, imgp->interpreter_name, td); |
| 224 | goto interpret; |
| 225 | } |
| 226 | |
| 227 | /* |
| 228 | * Copy out strings (args and env) and initialize stack base |
| 229 | */ |
| 230 | stack_base = exec_copyout_strings(imgp); |
| 231 | p->p_vmspace->vm_minsaddr = (char *)stack_base; |
| 232 | |
| 233 | /* |
| 234 | * If custom stack fixup routine present for this process |
| 235 | * let it do the stack setup. |
| 236 | * Else stuff argument count as first item on stack |
| 237 | */ |
| 238 | if (p->p_sysent->sv_fixup) |
| 239 | (*p->p_sysent->sv_fixup)(&stack_base, imgp); |
| 240 | else |
| 241 | suword(--stack_base, imgp->argc); |
| 242 | |
| 243 | /* |
| 244 | * For security and other reasons, the file descriptor table cannot |
| 245 | * be shared after an exec. |
| 246 | */ |
| 247 | if (p->p_fd->fd_refcnt > 1) { |
| 248 | struct filedesc *tmp; |
| 249 | |
| 250 | tmp = fdcopy(p); |
| 251 | fdfree(p); |
| 252 | p->p_fd = tmp; |
| 253 | } |
| 254 | |
| 255 | /* |
| 256 | * For security and other reasons, signal handlers cannot |
| 257 | * be shared after an exec. The new proces gets a copy of the old |
| 258 | * handlers. In execsigs(), the new process will have its signals |
| 259 | * reset. |
| 260 | */ |
| 261 | if (p->p_procsig->ps_refcnt > 1) { |
| 262 | struct procsig *newprocsig; |
| 263 | |
| 264 | MALLOC(newprocsig, struct procsig *, sizeof(struct procsig), |
| 265 | M_SUBPROC, M_WAITOK); |
| 266 | bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig)); |
| 267 | p->p_procsig->ps_refcnt--; |
| 268 | p->p_procsig = newprocsig; |
| 269 | p->p_procsig->ps_refcnt = 1; |
| 270 | if (p->p_sigacts == &p->p_addr->u_sigacts) |
| 271 | panic("shared procsig but private sigacts?"); |
| 272 | |
| 273 | p->p_addr->u_sigacts = *p->p_sigacts; |
| 274 | p->p_sigacts = &p->p_addr->u_sigacts; |
| 275 | } |
| 276 | |
| 277 | /* Stop profiling */ |
| 278 | stopprofclock(p); |
| 279 | |
| 280 | /* close files on exec */ |
| 281 | fdcloseexec(p); |
| 282 | |
| 283 | /* reset caught signals */ |
| 284 | execsigs(p); |
| 285 | |
| 286 | /* name this process - nameiexec(p, ndp) */ |
| 287 | len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); |
| 288 | bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); |
| 289 | p->p_comm[len] = 0; |
| 290 | |
| 291 | /* |
| 292 | * mark as execed, wakeup the process that vforked (if any) and tell |
| 293 | * it that it now has its own resources back |
| 294 | */ |
| 295 | p->p_flag |= P_EXEC; |
| 296 | if (p->p_pptr && (p->p_flag & P_PPWAIT)) { |
| 297 | p->p_flag &= ~P_PPWAIT; |
| 298 | wakeup((caddr_t)p->p_pptr); |
| 299 | } |
| 300 | |
| 301 | /* |
| 302 | * Implement image setuid/setgid. |
| 303 | * |
| 304 | * Don't honor setuid/setgid if the filesystem prohibits it or if |
| 305 | * the process is being traced. |
| 306 | */ |
| 307 | if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) || |
| 308 | ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) && |
| 309 | (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && |
| 310 | (p->p_flag & P_TRACED) == 0) { |
| 311 | /* |
| 312 | * Turn off syscall tracing for set-id programs, except for |
| 313 | * root. Record any set-id flags first to make sure that |
| 314 | * we do not regain any tracing during a possible block. |
| 315 | */ |
| 316 | setsugid(); |
| 317 | if (p->p_tracep && suser(td)) { |
| 318 | struct vnode *vtmp; |
| 319 | |
| 320 | if ((vtmp = p->p_tracep) != NULL) { |
| 321 | p->p_tracep = NULL; |
| 322 | p->p_traceflag = 0; |
| 323 | vrele(vtmp); |
| 324 | } |
| 325 | } |
| 326 | /* Close any file descriptors 0..2 that reference procfs */ |
| 327 | setugidsafety(p); |
| 328 | /* Make sure file descriptors 0..2 are in use. */ |
| 329 | error = fdcheckstd(p); |
| 330 | if (error != 0) |
| 331 | goto exec_fail_dealloc; |
| 332 | /* |
| 333 | * Set the new credentials. |
| 334 | */ |
| 335 | cratom(&p->p_ucred); |
| 336 | if (attr.va_mode & VSUID) |
| 337 | change_euid(attr.va_uid); |
| 338 | if (attr.va_mode & VSGID) |
| 339 | p->p_ucred->cr_gid = attr.va_gid; |
| 340 | |
| 341 | /* |
| 342 | * Clear local varsym variables |
| 343 | */ |
| 344 | varsymset_clean(&p->p_varsymset); |
| 345 | } else { |
| 346 | if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid && |
| 347 | p->p_ucred->cr_gid == p->p_ucred->cr_rgid) |
| 348 | p->p_flag &= ~P_SUGID; |
| 349 | } |
| 350 | |
| 351 | /* |
| 352 | * Implement correct POSIX saved-id behavior. |
| 353 | */ |
| 354 | if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid || |
| 355 | p->p_ucred->cr_svgid != p->p_ucred->cr_gid) { |
| 356 | cratom(&p->p_ucred); |
| 357 | p->p_ucred->cr_svuid = p->p_ucred->cr_uid; |
| 358 | p->p_ucred->cr_svgid = p->p_ucred->cr_gid; |
| 359 | } |
| 360 | |
| 361 | /* |
| 362 | * Store the vp for use in procfs |
| 363 | */ |
| 364 | if (p->p_textvp) /* release old reference */ |
| 365 | vrele(p->p_textvp); |
| 366 | VREF(ndp->ni_vp); |
| 367 | p->p_textvp = ndp->ni_vp; |
| 368 | |
| 369 | /* |
| 370 | * Notify others that we exec'd, and clear the P_INEXEC flag |
| 371 | * as we're now a bona fide freshly-execed process. |
| 372 | */ |
| 373 | KNOTE(&p->p_klist, NOTE_EXEC); |
| 374 | p->p_flag &= ~P_INEXEC; |
| 375 | |
| 376 | /* |
| 377 | * If tracing the process, trap to debugger so breakpoints |
| 378 | * can be set before the program executes. |
| 379 | */ |
| 380 | STOPEVENT(p, S_EXEC, 0); |
| 381 | |
| 382 | if (p->p_flag & P_TRACED) |
| 383 | psignal(p, SIGTRAP); |
| 384 | |
| 385 | /* clear "fork but no exec" flag, as we _are_ execing */ |
| 386 | p->p_acflag &= ~AFORK; |
| 387 | |
| 388 | /* Set values passed into the program in registers. */ |
| 389 | setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base, |
| 390 | imgp->ps_strings); |
| 391 | |
| 392 | /* |
| 393 | * The syscall result is returned in registers to the new program. |
| 394 | * Linux will register %edx as an atexit function and we must be |
| 395 | * sure to set it to 0. XXX |
| 396 | */ |
| 397 | uap->sysmsg_result64 = 0; |
| 398 | |
| 399 | /* Free any previous argument cache */ |
| 400 | if (p->p_args && --p->p_args->ar_ref == 0) |
| 401 | FREE(p->p_args, M_PARGS); |
| 402 | p->p_args = NULL; |
| 403 | |
| 404 | /* Cache arguments if they fit inside our allowance */ |
| 405 | i = imgp->endargs - imgp->stringbase; |
| 406 | if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { |
| 407 | MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i, |
| 408 | M_PARGS, M_WAITOK); |
| 409 | p->p_args->ar_ref = 1; |
| 410 | p->p_args->ar_length = i; |
| 411 | bcopy(imgp->stringbase, p->p_args->ar_args, i); |
| 412 | } |
| 413 | |
| 414 | exec_fail_dealloc: |
| 415 | |
| 416 | /* |
| 417 | * free various allocated resources |
| 418 | */ |
| 419 | if (imgp->firstpage) |
| 420 | exec_unmap_first_page(imgp); |
| 421 | |
| 422 | if (imgp->stringbase != NULL) |
| 423 | kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, |
| 424 | ARG_MAX + PAGE_SIZE); |
| 425 | |
| 426 | if (imgp->vp) { |
| 427 | NDFREE(ndp, NDF_ONLY_PNBUF); |
| 428 | vrele(imgp->vp); |
| 429 | } |
| 430 | |
| 431 | if (error == 0) |
| 432 | return (0); |
| 433 | |
| 434 | exec_fail: |
| 435 | /* we're done here, clear P_INEXEC */ |
| 436 | p->p_flag &= ~P_INEXEC; |
| 437 | if (imgp->vmspace_destroyed) { |
| 438 | /* sorry, no more process anymore. exit gracefully */ |
| 439 | exit1(W_EXITCODE(0, SIGABRT)); |
| 440 | /* NOT REACHED */ |
| 441 | return(0); |
| 442 | } else { |
| 443 | return(error); |
| 444 | } |
| 445 | } |
| 446 | |
| 447 | int |
| 448 | exec_map_first_page(struct image_params *imgp) |
| 449 | { |
| 450 | int s, rv, i; |
| 451 | int initial_pagein; |
| 452 | vm_page_t ma[VM_INITIAL_PAGEIN]; |
| 453 | vm_object_t object; |
| 454 | |
| 455 | |
| 456 | if (imgp->firstpage) { |
| 457 | exec_unmap_first_page(imgp); |
| 458 | } |
| 459 | |
| 460 | VOP_GETVOBJECT(imgp->vp, &object); |
| 461 | s = splvm(); |
| 462 | |
| 463 | ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); |
| 464 | |
| 465 | if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { |
| 466 | initial_pagein = VM_INITIAL_PAGEIN; |
| 467 | if (initial_pagein > object->size) |
| 468 | initial_pagein = object->size; |
| 469 | for (i = 1; i < initial_pagein; i++) { |
| 470 | if ((ma[i] = vm_page_lookup(object, i)) != NULL) { |
| 471 | if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) |
| 472 | break; |
| 473 | if (ma[i]->valid) |
| 474 | break; |
| 475 | vm_page_busy(ma[i]); |
| 476 | } else { |
| 477 | ma[i] = vm_page_alloc(object, i, VM_ALLOC_NORMAL); |
| 478 | if (ma[i] == NULL) |
| 479 | break; |
| 480 | } |
| 481 | } |
| 482 | initial_pagein = i; |
| 483 | |
| 484 | rv = vm_pager_get_pages(object, ma, initial_pagein, 0); |
| 485 | ma[0] = vm_page_lookup(object, 0); |
| 486 | |
| 487 | if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || (ma[0]->valid == 0)) { |
| 488 | if (ma[0]) { |
| 489 | vm_page_protect(ma[0], VM_PROT_NONE); |
| 490 | vm_page_free(ma[0]); |
| 491 | } |
| 492 | splx(s); |
| 493 | return EIO; |
| 494 | } |
| 495 | } |
| 496 | |
| 497 | vm_page_wire(ma[0]); |
| 498 | vm_page_wakeup(ma[0]); |
| 499 | splx(s); |
| 500 | |
| 501 | pmap_kenter((vm_offset_t) imgp->image_header, VM_PAGE_TO_PHYS(ma[0])); |
| 502 | imgp->firstpage = ma[0]; |
| 503 | |
| 504 | return 0; |
| 505 | } |
| 506 | |
| 507 | void |
| 508 | exec_unmap_first_page(imgp) |
| 509 | struct image_params *imgp; |
| 510 | { |
| 511 | if (imgp->firstpage) { |
| 512 | pmap_kremove((vm_offset_t) imgp->image_header); |
| 513 | vm_page_unwire(imgp->firstpage, 1); |
| 514 | imgp->firstpage = NULL; |
| 515 | } |
| 516 | } |
| 517 | |
| 518 | /* |
| 519 | * Destroy old address space, and allocate a new stack |
| 520 | * The new stack is only SGROWSIZ large because it is grown |
| 521 | * automatically in trap.c. |
| 522 | */ |
| 523 | int |
| 524 | exec_new_vmspace(imgp) |
| 525 | struct image_params *imgp; |
| 526 | { |
| 527 | int error; |
| 528 | struct vmspace *vmspace = imgp->proc->p_vmspace; |
| 529 | vm_offset_t stack_addr = USRSTACK - maxssiz; |
| 530 | vm_map_t map = &vmspace->vm_map; |
| 531 | |
| 532 | imgp->vmspace_destroyed = 1; |
| 533 | |
| 534 | /* |
| 535 | * Prevent a pending AIO from modifying the new address space. |
| 536 | */ |
| 537 | aio_proc_rundown(imgp->proc); |
| 538 | |
| 539 | /* |
| 540 | * Blow away entire process VM, if address space not shared, |
| 541 | * otherwise, create a new VM space so that other threads are |
| 542 | * not disrupted |
| 543 | */ |
| 544 | if (vmspace->vm_refcnt == 1) { |
| 545 | shmexit(vmspace); |
| 546 | pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS); |
| 547 | vm_map_remove(map, 0, VM_MAXUSER_ADDRESS); |
| 548 | } else { |
| 549 | vmspace_exec(imgp->proc); |
| 550 | vmspace = imgp->proc->p_vmspace; |
| 551 | map = &vmspace->vm_map; |
| 552 | } |
| 553 | |
| 554 | /* Allocate a new stack */ |
| 555 | error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz, |
| 556 | VM_PROT_ALL, VM_PROT_ALL, 0); |
| 557 | if (error) |
| 558 | return (error); |
| 559 | |
| 560 | /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the |
| 561 | * VM_STACK case, but they are still used to monitor the size of the |
| 562 | * process stack so we can check the stack rlimit. |
| 563 | */ |
| 564 | vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; |
| 565 | vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz; |
| 566 | |
| 567 | return(0); |
| 568 | } |
| 569 | |
| 570 | /* |
| 571 | * Copy out argument and environment strings from the old process |
| 572 | * address space into the temporary string buffer. |
| 573 | */ |
| 574 | int |
| 575 | exec_extract_strings(imgp) |
| 576 | struct image_params *imgp; |
| 577 | { |
| 578 | char **argv, **envv; |
| 579 | char *argp, *envp; |
| 580 | int error; |
| 581 | size_t length; |
| 582 | |
| 583 | /* |
| 584 | * extract arguments first |
| 585 | */ |
| 586 | |
| 587 | argv = imgp->uap->argv; |
| 588 | |
| 589 | if (argv) { |
| 590 | argp = (caddr_t) (intptr_t) fuword(argv); |
| 591 | if (argp == (caddr_t) -1) |
| 592 | return (EFAULT); |
| 593 | if (argp) |
| 594 | argv++; |
| 595 | if (imgp->argv0) |
| 596 | argp = imgp->argv0; |
| 597 | if (argp) { |
| 598 | do { |
| 599 | if (argp == (caddr_t) -1) |
| 600 | return (EFAULT); |
| 601 | if ((error = copyinstr(argp, imgp->stringp, |
| 602 | imgp->stringspace, &length))) { |
| 603 | if (error == ENAMETOOLONG) |
| 604 | return(E2BIG); |
| 605 | return (error); |
| 606 | } |
| 607 | imgp->stringspace -= length; |
| 608 | imgp->stringp += length; |
| 609 | imgp->argc++; |
| 610 | } while ((argp = (caddr_t) (intptr_t) fuword(argv++))); |
| 611 | } |
| 612 | } |
| 613 | |
| 614 | imgp->endargs = imgp->stringp; |
| 615 | |
| 616 | /* |
| 617 | * extract environment strings |
| 618 | */ |
| 619 | |
| 620 | envv = imgp->uap->envv; |
| 621 | |
| 622 | if (envv) { |
| 623 | while ((envp = (caddr_t) (intptr_t) fuword(envv++))) { |
| 624 | if (envp == (caddr_t) -1) |
| 625 | return (EFAULT); |
| 626 | if ((error = copyinstr(envp, imgp->stringp, |
| 627 | imgp->stringspace, &length))) { |
| 628 | if (error == ENAMETOOLONG) |
| 629 | return(E2BIG); |
| 630 | return (error); |
| 631 | } |
| 632 | imgp->stringspace -= length; |
| 633 | imgp->stringp += length; |
| 634 | imgp->envc++; |
| 635 | } |
| 636 | } |
| 637 | |
| 638 | return (0); |
| 639 | } |
| 640 | |
| 641 | /* |
| 642 | * Copy strings out to the new process address space, constructing |
| 643 | * new arg and env vector tables. Return a pointer to the base |
| 644 | * so that it can be used as the initial stack pointer. |
| 645 | */ |
| 646 | register_t * |
| 647 | exec_copyout_strings(imgp) |
| 648 | struct image_params *imgp; |
| 649 | { |
| 650 | int argc, envc; |
| 651 | char **vectp; |
| 652 | char *stringp, *destp; |
| 653 | register_t *stack_base; |
| 654 | struct ps_strings *arginfo; |
| 655 | int szsigcode; |
| 656 | |
| 657 | /* |
| 658 | * Calculate string base and vector table pointers. |
| 659 | * Also deal with signal trampoline code for this exec type. |
| 660 | */ |
| 661 | arginfo = (struct ps_strings *)PS_STRINGS; |
| 662 | szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); |
| 663 | destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - |
| 664 | roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); |
| 665 | |
| 666 | /* |
| 667 | * install sigcode |
| 668 | */ |
| 669 | if (szsigcode) |
| 670 | copyout(imgp->proc->p_sysent->sv_sigcode, |
| 671 | ((caddr_t)arginfo - szsigcode), szsigcode); |
| 672 | |
| 673 | /* |
| 674 | * If we have a valid auxargs ptr, prepare some room |
| 675 | * on the stack. |
| 676 | */ |
| 677 | if (imgp->auxargs) |
| 678 | /* |
| 679 | * The '+ 2' is for the null pointers at the end of each of the |
| 680 | * arg and env vector sets, and 'AT_COUNT*2' is room for the |
| 681 | * ELF Auxargs data. |
| 682 | */ |
| 683 | vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + |
| 684 | AT_COUNT*2) * sizeof(char*)); |
| 685 | else |
| 686 | /* |
| 687 | * The '+ 2' is for the null pointers at the end of each of the |
| 688 | * arg and env vector sets |
| 689 | */ |
| 690 | vectp = (char **) |
| 691 | (destp - (imgp->argc + imgp->envc + 2) * sizeof(char*)); |
| 692 | |
| 693 | /* |
| 694 | * vectp also becomes our initial stack base |
| 695 | */ |
| 696 | stack_base = (register_t *)vectp; |
| 697 | |
| 698 | stringp = imgp->stringbase; |
| 699 | argc = imgp->argc; |
| 700 | envc = imgp->envc; |
| 701 | |
| 702 | /* |
| 703 | * Copy out strings - arguments and environment. |
| 704 | */ |
| 705 | copyout(stringp, destp, ARG_MAX - imgp->stringspace); |
| 706 | |
| 707 | /* |
| 708 | * Fill in "ps_strings" struct for ps, w, etc. |
| 709 | */ |
| 710 | suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); |
| 711 | suword(&arginfo->ps_nargvstr, argc); |
| 712 | |
| 713 | /* |
| 714 | * Fill in argument portion of vector table. |
| 715 | */ |
| 716 | for (; argc > 0; --argc) { |
| 717 | suword(vectp++, (long)(intptr_t)destp); |
| 718 | while (*stringp++ != 0) |
| 719 | destp++; |
| 720 | destp++; |
| 721 | } |
| 722 | |
| 723 | /* a null vector table pointer seperates the argp's from the envp's */ |
| 724 | suword(vectp++, 0); |
| 725 | |
| 726 | suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); |
| 727 | suword(&arginfo->ps_nenvstr, envc); |
| 728 | |
| 729 | /* |
| 730 | * Fill in environment portion of vector table. |
| 731 | */ |
| 732 | for (; envc > 0; --envc) { |
| 733 | suword(vectp++, (long)(intptr_t)destp); |
| 734 | while (*stringp++ != 0) |
| 735 | destp++; |
| 736 | destp++; |
| 737 | } |
| 738 | |
| 739 | /* end of vector table is a null pointer */ |
| 740 | suword(vectp, 0); |
| 741 | |
| 742 | return (stack_base); |
| 743 | } |
| 744 | |
| 745 | /* |
| 746 | * Check permissions of file to execute. |
| 747 | * Return 0 for success or error code on failure. |
| 748 | */ |
| 749 | int |
| 750 | exec_check_permissions(imgp) |
| 751 | struct image_params *imgp; |
| 752 | { |
| 753 | struct proc *p = imgp->proc; |
| 754 | struct vnode *vp = imgp->vp; |
| 755 | struct vattr *attr = imgp->attr; |
| 756 | struct thread *td = p->p_thread; |
| 757 | int error; |
| 758 | |
| 759 | /* Get file attributes */ |
| 760 | error = VOP_GETATTR(vp, attr, td); |
| 761 | if (error) |
| 762 | return (error); |
| 763 | |
| 764 | /* |
| 765 | * 1) Check if file execution is disabled for the filesystem that this |
| 766 | * file resides on. |
| 767 | * 2) Insure that at least one execute bit is on - otherwise root |
| 768 | * will always succeed, and we don't want to happen unless the |
| 769 | * file really is executable. |
| 770 | * 3) Insure that the file is a regular file. |
| 771 | */ |
| 772 | if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || |
| 773 | ((attr->va_mode & 0111) == 0) || |
| 774 | (attr->va_type != VREG)) { |
| 775 | return (EACCES); |
| 776 | } |
| 777 | |
| 778 | /* |
| 779 | * Zero length files can't be exec'd |
| 780 | */ |
| 781 | if (attr->va_size == 0) |
| 782 | return (ENOEXEC); |
| 783 | |
| 784 | /* |
| 785 | * Check for execute permission to file based on current credentials. |
| 786 | */ |
| 787 | error = VOP_ACCESS(vp, VEXEC, p->p_ucred, td); |
| 788 | if (error) |
| 789 | return (error); |
| 790 | |
| 791 | /* |
| 792 | * Check number of open-for-writes on the file and deny execution |
| 793 | * if there are any. |
| 794 | */ |
| 795 | if (vp->v_writecount) |
| 796 | return (ETXTBSY); |
| 797 | |
| 798 | /* |
| 799 | * Call filesystem specific open routine (which does nothing in the |
| 800 | * general case). |
| 801 | */ |
| 802 | error = VOP_OPEN(vp, FREAD, p->p_ucred, td); |
| 803 | if (error) |
| 804 | return (error); |
| 805 | |
| 806 | return (0); |
| 807 | } |
| 808 | |
| 809 | /* |
| 810 | * Exec handler registration |
| 811 | */ |
| 812 | int |
| 813 | exec_register(execsw_arg) |
| 814 | const struct execsw *execsw_arg; |
| 815 | { |
| 816 | const struct execsw **es, **xs, **newexecsw; |
| 817 | int count = 2; /* New slot and trailing NULL */ |
| 818 | |
| 819 | if (execsw) |
| 820 | for (es = execsw; *es; es++) |
| 821 | count++; |
| 822 | newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); |
| 823 | if (newexecsw == NULL) |
| 824 | return ENOMEM; |
| 825 | xs = newexecsw; |
| 826 | if (execsw) |
| 827 | for (es = execsw; *es; es++) |
| 828 | *xs++ = *es; |
| 829 | *xs++ = execsw_arg; |
| 830 | *xs = NULL; |
| 831 | if (execsw) |
| 832 | free(execsw, M_TEMP); |
| 833 | execsw = newexecsw; |
| 834 | return 0; |
| 835 | } |
| 836 | |
| 837 | int |
| 838 | exec_unregister(execsw_arg) |
| 839 | const struct execsw *execsw_arg; |
| 840 | { |
| 841 | const struct execsw **es, **xs, **newexecsw; |
| 842 | int count = 1; |
| 843 | |
| 844 | if (execsw == NULL) |
| 845 | panic("unregister with no handlers left?\n"); |
| 846 | |
| 847 | for (es = execsw; *es; es++) { |
| 848 | if (*es == execsw_arg) |
| 849 | break; |
| 850 | } |
| 851 | if (*es == NULL) |
| 852 | return ENOENT; |
| 853 | for (es = execsw; *es; es++) |
| 854 | if (*es != execsw_arg) |
| 855 | count++; |
| 856 | newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); |
| 857 | if (newexecsw == NULL) |
| 858 | return ENOMEM; |
| 859 | xs = newexecsw; |
| 860 | for (es = execsw; *es; es++) |
| 861 | if (*es != execsw_arg) |
| 862 | *xs++ = *es; |
| 863 | *xs = NULL; |
| 864 | if (execsw) |
| 865 | free(execsw, M_TEMP); |
| 866 | execsw = newexecsw; |
| 867 | return 0; |
| 868 | } |