1 /*- 2 * Copyright (c) 2003 Kip Macy 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 * $DragonFly: src/sys/kern/kern_checkpoint.c,v 1.19 2007/06/29 23:40:00 dillon Exp $ 27 */ 28 29 #include <sys/types.h> 30 #include <sys/param.h> 31 #include <sys/proc.h> 32 #include <sys/module.h> 33 #include <sys/sysent.h> 34 #include <sys/kernel.h> 35 #include <sys/systm.h> 36 #include <sys/nlookup.h> 37 38 #include <sys/file.h> 39 /* only on dragonfly */ 40 #include <sys/file2.h> 41 #include <sys/fcntl.h> 42 #include <sys/signal.h> 43 #include <vm/vm_param.h> 44 #include <vm/vm.h> 45 #include <sys/imgact_elf.h> 46 #include <sys/procfs.h> 47 48 #include <sys/lock.h> 49 #include <vm/pmap.h> 50 #include <vm/vm_map.h> 51 #include <vm/vm_extern.h> 52 #include <sys/mman.h> 53 #include <sys/sysent.h> 54 #include <sys/sysproto.h> 55 #include <sys/resource.h> 56 #include <sys/resourcevar.h> 57 #include <sys/malloc.h> 58 #include <sys/stat.h> 59 #include <sys/uio.h> 60 #include <sys/namei.h> 61 #include <sys/vnode.h> 62 #include <machine/limits.h> 63 #include <machine/frame.h> 64 #include <sys/signalvar.h> 65 #include <sys/syslog.h> 66 #include <sys/sysctl.h> 67 #include <machine/sigframe.h> 68 #include <sys/exec.h> 69 #include <sys/unistd.h> 70 #include <sys/time.h> 71 #include <sys/kern_syscall.h> 72 #include <sys/checkpoint.h> 73 #include <sys/mount.h> 74 #include <sys/ckpt.h> 75 76 77 static int elf_loadphdrs(struct file *fp, Elf_Phdr *phdr, int numsegs); 78 static int elf_getnotes(struct lwp *lp, struct file *fp, size_t notesz); 79 static int elf_demarshalnotes(void *src, prpsinfo_t *psinfo, 80 prstatus_t *status, prfpregset_t *fpregset, int nthreads); 81 static int elf_loadnotes(struct lwp *, prpsinfo_t *, prstatus_t *, 82 prfpregset_t *); 83 static int elf_getsigs(struct lwp *lp, struct file *fp); 84 static int elf_getfiles(struct proc *p, struct file *fp); 85 static int elf_gettextvp(struct proc *p, struct file *fp); 86 static char *ckpt_expand_name(const char *name, uid_t uid, pid_t pid); 87 88 static int ckptgroup = 0; /* wheel only, -1 for any group */ 89 SYSCTL_INT(_kern, OID_AUTO, ckptgroup, CTLFLAG_RW, &ckptgroup, 0, ""); 90 91 /* ref count to see how many processes that are being checkpointed */ 92 static int chptinuse = 0; 93 94 static __inline 95 int 96 read_check(struct file *fp, void *buf, size_t nbyte) 97 { 98 size_t nread; 99 int error; 100 101 PRINTF(("reading %d bytes\n", nbyte)); 102 error = fp_read(fp, buf, nbyte, &nread, 1, UIO_SYSSPACE); 103 if (error) { 104 PRINTF(("read failed - %d", error)); 105 } else if (nread != nbyte) { 106 PRINTF(("wanted to read %d - read %d\n", nbyte, nread)); 107 error = EINVAL; 108 } 109 return error; 110 } 111 112 static int 113 elf_gethdr(struct file *fp, Elf_Ehdr *ehdr) 114 { 115 size_t nbyte = sizeof(Elf_Ehdr); 116 int error; 117 118 if ((error = read_check(fp, ehdr, nbyte)) != 0) 119 goto done; 120 if (!(ehdr->e_ehsize == sizeof(Elf_Ehdr))) { 121 PRINTF(("wrong elf header size: %d\n" 122 "expected size : %d\n", 123 ehdr->e_ehsize, sizeof(Elf_Ehdr))); 124 return EINVAL; 125 } 126 if (!(ehdr->e_phentsize == sizeof(Elf_Phdr))) { 127 PRINTF(("wrong program header size: %d\n" 128 "expected size : %d\n", 129 ehdr->e_phentsize, sizeof(Elf_Phdr))); 130 return EINVAL; 131 } 132 133 if (!(ehdr->e_ident[EI_MAG0] == ELFMAG0 && 134 ehdr->e_ident[EI_MAG1] == ELFMAG1 && 135 ehdr->e_ident[EI_MAG2] == ELFMAG2 && 136 ehdr->e_ident[EI_MAG3] == ELFMAG3 && 137 ehdr->e_ident[EI_CLASS] == ELF_CLASS && 138 ehdr->e_ident[EI_DATA] == ELF_DATA && 139 ehdr->e_ident[EI_VERSION] == EV_CURRENT && 140 ehdr->e_ident[EI_OSABI] == ELFOSABI_FREEBSD && 141 ehdr->e_ident[EI_ABIVERSION] == 0)) { 142 PRINTF(("bad elf header\n there are %d segments\n", 143 ehdr->e_phnum)); 144 return EINVAL; 145 146 } 147 PRINTF(("Elf header size: %d\n", ehdr->e_ehsize)); 148 PRINTF(("Program header size: %d\n", ehdr->e_phentsize)); 149 PRINTF(("Number of Program headers: %d\n", ehdr->e_phnum)); 150 done: 151 return error; 152 } 153 154 static int 155 elf_getphdrs(struct file *fp, Elf_Phdr *phdr, size_t nbyte) 156 { 157 int i; 158 int error; 159 int nheaders = nbyte/sizeof(Elf_Phdr); 160 161 PRINTF(("reading phdrs section\n")); 162 if ((error = read_check(fp, phdr, nbyte)) != 0) 163 goto done; 164 PRINTF(("headers section:\n")); 165 for (i = 0; i < nheaders; i++) { 166 PRINTF(("entry type: %d\n", phdr[i].p_type)); 167 PRINTF(("file offset: %d\n", phdr[i].p_offset)); 168 PRINTF(("virt address: %p\n", (uint32_t *)phdr[i].p_vaddr)); 169 PRINTF(("file size: %d\n", phdr[i].p_filesz)); 170 PRINTF(("memory size: %d\n", phdr[i].p_memsz)); 171 PRINTF(("\n")); 172 } 173 done: 174 return error; 175 } 176 177 178 static int 179 elf_getnotes(struct lwp *lp, struct file *fp, size_t notesz) 180 { 181 int error; 182 int nthreads; 183 char *note; 184 prpsinfo_t *psinfo; 185 prstatus_t *status; 186 prfpregset_t *fpregset; 187 188 nthreads = (notesz - sizeof(prpsinfo_t))/(sizeof(prstatus_t) + 189 sizeof(prfpregset_t)); 190 PRINTF(("reading notes header nthreads=%d\n", nthreads)); 191 if (nthreads <= 0 || nthreads > CKPT_MAXTHREADS) 192 return EINVAL; 193 194 psinfo = kmalloc(sizeof(prpsinfo_t), M_TEMP, M_ZERO | M_WAITOK); 195 status = kmalloc(nthreads*sizeof(prstatus_t), M_TEMP, M_WAITOK); 196 fpregset = kmalloc(nthreads*sizeof(prfpregset_t), M_TEMP, M_WAITOK); 197 note = kmalloc(notesz, M_TEMP, M_WAITOK); 198 199 200 PRINTF(("reading notes section\n")); 201 if ((error = read_check(fp, note, notesz)) != 0) 202 goto done; 203 error = elf_demarshalnotes(note, psinfo, status, fpregset, nthreads); 204 if (error) 205 goto done; 206 /* fetch register state from notes */ 207 error = elf_loadnotes(lp, psinfo, status, fpregset); 208 done: 209 if (psinfo) 210 kfree(psinfo, M_TEMP); 211 if (status) 212 kfree(status, M_TEMP); 213 if (fpregset) 214 kfree(fpregset, M_TEMP); 215 if (note) 216 kfree(note, M_TEMP); 217 return error; 218 } 219 220 static int 221 ckpt_thaw_proc(struct lwp *lp, struct file *fp) 222 { 223 struct proc *p = lp->lwp_proc; 224 Elf_Phdr *phdr = NULL; 225 Elf_Ehdr *ehdr = NULL; 226 int error; 227 size_t nbyte; 228 229 TRACE_ENTER; 230 231 ehdr = kmalloc(sizeof(Elf_Ehdr), M_TEMP, M_ZERO | M_WAITOK); 232 233 if ((error = elf_gethdr(fp, ehdr)) != 0) 234 goto done; 235 nbyte = sizeof(Elf_Phdr) * ehdr->e_phnum; 236 phdr = kmalloc(nbyte, M_TEMP, M_WAITOK); 237 238 /* fetch description of program writable mappings */ 239 if ((error = elf_getphdrs(fp, phdr, nbyte)) != 0) 240 goto done; 241 242 /* fetch notes section containing register state */ 243 if ((error = elf_getnotes(lp, fp, phdr->p_filesz)) != 0) 244 goto done; 245 246 /* fetch program text vnodes */ 247 if ((error = elf_gettextvp(p, fp)) != 0) 248 goto done; 249 250 /* fetch signal disposition */ 251 if ((error = elf_getsigs(lp, fp)) != 0) { 252 kprintf("failure in recovering signals\n"); 253 goto done; 254 } 255 256 /* fetch open files */ 257 if ((error = elf_getfiles(p, fp)) != 0) 258 goto done; 259 260 /* handle mappings last in case we are reading from a socket */ 261 error = elf_loadphdrs(fp, phdr, ehdr->e_phnum); 262 263 /* 264 * Set the textvp to the checkpoint file and mark the vnode so 265 * a future checkpointing of this checkpoint-restored program 266 * will copy out the contents of the mappings rather then trying 267 * to record the vnode info related to the checkpoint file, which 268 * is likely going to be destroyed when the program is re-checkpointed. 269 */ 270 if (error == 0 && fp->f_data && fp->f_type == DTYPE_VNODE) { 271 if (p->p_textvp) 272 vrele(p->p_textvp); 273 p->p_textvp = (struct vnode *)fp->f_data; 274 p->p_textvp->v_flag |= VCKPT; 275 vref(p->p_textvp); 276 } 277 done: 278 if (ehdr) 279 kfree(ehdr, M_TEMP); 280 if (phdr) 281 kfree(phdr, M_TEMP); 282 TRACE_EXIT; 283 return error; 284 } 285 286 static int 287 elf_loadnotes(struct lwp *lp, prpsinfo_t *psinfo, prstatus_t *status, 288 prfpregset_t *fpregset) 289 { 290 struct proc *p = lp->lwp_proc; 291 int error; 292 293 /* validate status and psinfo */ 294 TRACE_ENTER; 295 if (status->pr_version != PRSTATUS_VERSION || 296 status->pr_statussz != sizeof(prstatus_t) || 297 status->pr_gregsetsz != sizeof(gregset_t) || 298 status->pr_fpregsetsz != sizeof(fpregset_t) || 299 psinfo->pr_version != PRPSINFO_VERSION || 300 psinfo->pr_psinfosz != sizeof(prpsinfo_t)) { 301 PRINTF(("status check failed\n")); 302 error = EINVAL; 303 goto done; 304 } 305 /* XXX lwp handle more than one lwp*/ 306 if ((error = set_regs(lp, &status->pr_reg)) != 0) 307 goto done; 308 error = set_fpregs(lp, fpregset); 309 strlcpy(p->p_comm, psinfo->pr_fname, sizeof(p->p_comm)); 310 /* XXX psinfo->pr_psargs not yet implemented */ 311 done: 312 TRACE_EXIT; 313 return error; 314 } 315 316 static int 317 elf_getnote(void *src, size_t *off, const char *name, unsigned int type, 318 void **desc, size_t descsz) 319 { 320 Elf_Note note; 321 int error; 322 323 TRACE_ENTER; 324 if (src == NULL) { 325 error = EFAULT; 326 goto done; 327 } 328 bcopy((char *)src + *off, ¬e, sizeof note); 329 330 PRINTF(("at offset: %d expected note of type: %d - got: %d\n", 331 *off, type, note.n_type)); 332 *off += sizeof note; 333 if (type != note.n_type) { 334 TRACE_ERR; 335 error = EINVAL; 336 goto done; 337 } 338 if (strncmp(name, (char *) src + *off, note.n_namesz) != 0) { 339 error = EINVAL; 340 goto done; 341 } 342 *off += roundup2(note.n_namesz, sizeof(Elf_Size)); 343 if (note.n_descsz != descsz) { 344 TRACE_ERR; 345 error = EINVAL; 346 goto done; 347 } 348 if (desc) 349 bcopy((char *)src + *off, *desc, note.n_descsz); 350 *off += roundup2(note.n_descsz, sizeof(Elf_Size)); 351 error = 0; 352 done: 353 TRACE_EXIT; 354 return error; 355 } 356 357 static int 358 elf_demarshalnotes(void *src, prpsinfo_t *psinfo, prstatus_t *status, 359 prfpregset_t *fpregset, int nthreads) 360 { 361 int i; 362 int error; 363 int off = 0; 364 365 TRACE_ENTER; 366 error = elf_getnote(src, &off, "FreeBSD", NT_PRSTATUS, 367 (void **)&status, sizeof(prstatus_t)); 368 if (error) 369 goto done; 370 error = elf_getnote(src, &off, "FreeBSD", NT_FPREGSET, 371 (void **)&fpregset, sizeof(prfpregset_t)); 372 if (error) 373 goto done; 374 error = elf_getnote(src, &off, "FreeBSD", NT_PRPSINFO, 375 (void **)&psinfo, sizeof(prpsinfo_t)); 376 if (error) 377 goto done; 378 379 /* 380 * The remaining portion needs to be an integer multiple 381 * of prstatus_t and prfpregset_t 382 */ 383 for (i = 0 ; i < nthreads - 1; i++) { 384 status++; fpregset++; 385 error = elf_getnote(src, &off, "FreeBSD", NT_PRSTATUS, 386 (void **)&status, sizeof (prstatus_t)); 387 if (error) 388 goto done; 389 error = elf_getnote(src, &off, "FreeBSD", NT_FPREGSET, 390 (void **)&fpregset, sizeof(prfpregset_t)); 391 if (error) 392 goto done; 393 } 394 395 done: 396 TRACE_EXIT; 397 return error; 398 } 399 400 401 static int 402 mmap_phdr(struct file *fp, Elf_Phdr *phdr) 403 { 404 int error; 405 size_t len; 406 int prot; 407 void *addr; 408 int flags; 409 off_t pos; 410 411 TRACE_ENTER; 412 pos = phdr->p_offset; 413 len = phdr->p_filesz; 414 addr = (void *)phdr->p_vaddr; 415 flags = MAP_FIXED | MAP_NOSYNC | MAP_PRIVATE; 416 prot = 0; 417 if (phdr->p_flags & PF_R) 418 prot |= PROT_READ; 419 if (phdr->p_flags & PF_W) 420 prot |= PROT_WRITE; 421 if (phdr->p_flags & PF_X) 422 prot |= PROT_EXEC; 423 if ((error = fp_mmap(addr, len, prot, flags, fp, pos, &addr)) != 0) { 424 PRINTF(("mmap failed: %d\n", error); ); 425 } 426 PRINTF(("map @%08x-%08x fileoff %08x-%08x\n", (int)addr, 427 (int)((char *)addr + len), (int)pos, (int)(pos + len))); 428 TRACE_EXIT; 429 return error; 430 } 431 432 /* 433 * Load memory mapped segments. The segments are backed by the checkpoint 434 * file. 435 */ 436 static int 437 elf_loadphdrs(struct file *fp, Elf_Phdr *phdr, int numsegs) 438 { 439 int i; 440 int error = 0; 441 442 TRACE_ENTER; 443 for (i = 1; i < numsegs; i++) { 444 if ((error = mmap_phdr(fp, &phdr[i])) != 0) 445 break; 446 } 447 TRACE_EXIT; 448 return error; 449 } 450 451 static int 452 elf_getsigs(struct lwp *lp, struct file *fp) 453 { 454 struct proc *p = lp->lwp_proc; 455 int error; 456 struct ckpt_siginfo *csi; 457 458 TRACE_ENTER; 459 csi = kmalloc(sizeof(struct ckpt_siginfo), M_TEMP, M_ZERO | M_WAITOK); 460 if ((error = read_check(fp, csi, sizeof(struct ckpt_siginfo))) != 0) 461 goto done; 462 463 if (csi->csi_ckptpisz != sizeof(struct ckpt_siginfo)) { 464 TRACE_ERR; 465 error = EINVAL; 466 goto done; 467 } 468 bcopy(&csi->csi_sigacts, p->p_sigacts, sizeof(p->p_sigacts)); 469 bcopy(&csi->csi_itimerval, &p->p_realtimer, sizeof(struct itimerval)); 470 SIG_CANTMASK(csi->csi_sigmask); 471 /* XXX lwp handle more than one lwp */ 472 bcopy(&csi->csi_sigmask, &lp->lwp_sigmask, sizeof(sigset_t)); 473 p->p_sigparent = csi->csi_sigparent; 474 done: 475 if (csi) 476 kfree(csi, M_TEMP); 477 TRACE_EXIT; 478 return error; 479 } 480 481 /* 482 * Returns a locked, refd vnode 483 */ 484 static int 485 ckpt_fhtovp(fhandle_t *fh, struct vnode **vpp) 486 { 487 struct mount *mp; 488 int error; 489 490 TRACE_ENTER; 491 mp = vfs_getvfs(&fh->fh_fsid); 492 493 if (!mp) { 494 TRACE_ERR; 495 PRINTF(("failed to get mount - ESTALE\n")); 496 TRACE_EXIT; 497 return ESTALE; 498 } 499 error = VFS_FHTOVP(mp, &fh->fh_fid, vpp); 500 if (error) { 501 PRINTF(("failed with: %d\n", error)); 502 TRACE_ERR; 503 TRACE_EXIT; 504 return error; 505 } 506 TRACE_EXIT; 507 return 0; 508 } 509 510 static int 511 mmap_vp(struct vn_hdr *vnh) 512 { 513 struct vnode *vp; 514 Elf_Phdr *phdr; 515 struct file *fp; 516 int error; 517 TRACE_ENTER; 518 519 phdr = &vnh->vnh_phdr; 520 521 if ((error = ckpt_fhtovp(&vnh->vnh_fh, &vp)) != 0) 522 return error; 523 /* 524 * XXX O_RDONLY -> or O_RDWR if file is PROT_WRITE, MAP_SHARED 525 */ 526 if ((error = fp_vpopen(vp, O_RDONLY, &fp)) != 0) { 527 vput(vp); 528 return error; 529 } 530 error = mmap_phdr(fp, phdr); 531 fp_close(fp); 532 TRACE_EXIT; 533 return error; 534 } 535 536 537 static int 538 elf_gettextvp(struct proc *p, struct file *fp) 539 { 540 int i; 541 int error; 542 int vpcount; 543 struct ckpt_vminfo vminfo; 544 struct vn_hdr *vnh = NULL; 545 546 TRACE_ENTER; 547 if ((error = read_check(fp, &vminfo, sizeof(vminfo))) != 0) 548 goto done; 549 if (vminfo.cvm_dsize < 0 || 550 vminfo.cvm_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur || 551 vminfo.cvm_tsize < 0 || 552 (u_quad_t)vminfo.cvm_tsize > maxtsiz || 553 vminfo.cvm_daddr >= (caddr_t)VM_MAX_USER_ADDRESS || 554 vminfo.cvm_taddr >= (caddr_t)VM_MAX_USER_ADDRESS 555 ) { 556 error = ERANGE; 557 goto done; 558 } 559 560 vmspace_exec(p, NULL); 561 p->p_vmspace->vm_daddr = vminfo.cvm_daddr; 562 p->p_vmspace->vm_dsize = vminfo.cvm_dsize; 563 p->p_vmspace->vm_taddr = vminfo.cvm_taddr; 564 p->p_vmspace->vm_tsize = vminfo.cvm_tsize; 565 if ((error = read_check(fp, &vpcount, sizeof(int))) != 0) 566 goto done; 567 vnh = kmalloc(sizeof(struct vn_hdr) * vpcount, M_TEMP, M_WAITOK); 568 if ((error = read_check(fp, vnh, sizeof(struct vn_hdr)*vpcount)) != 0) 569 goto done; 570 for (i = 0; i < vpcount; i++) { 571 if ((error = mmap_vp(&vnh[i])) != 0) 572 goto done; 573 } 574 575 done: 576 if (vnh) 577 kfree(vnh, M_TEMP); 578 TRACE_EXIT; 579 return error; 580 } 581 582 583 584 /* place holder */ 585 static int 586 elf_getfiles(struct proc *p, struct file *fp) 587 { 588 int error; 589 int i; 590 int filecount; 591 int fd; 592 struct ckpt_filehdr filehdr; 593 struct ckpt_fileinfo *cfi_base = NULL; 594 struct vnode *vp; 595 struct file *tempfp; 596 struct file *ofp; 597 598 TRACE_ENTER; 599 if ((error = read_check(fp, &filehdr, sizeof(filehdr))) != 0) 600 goto done; 601 filecount = filehdr.cfh_nfiles; 602 cfi_base = kmalloc(filecount*sizeof(struct ckpt_fileinfo), M_TEMP, M_WAITOK); 603 error = read_check(fp, cfi_base, filecount*sizeof(struct ckpt_fileinfo)); 604 if (error) 605 goto done; 606 607 /* 608 * Close all file descriptors >= 3. These descriptors are from the 609 * checkpt(1) program itself and should not be retained. 610 * 611 * XXX we need a flag so a checkpoint restore can opt to supply the 612 * descriptors, or the non-regular-file descripors. 613 */ 614 for (i = 3; i < p->p_fd->fd_nfiles; ++i) 615 kern_close(i); 616 617 /* 618 * Scan files to load 619 */ 620 for (i = 0; i < filecount; i++) { 621 struct ckpt_fileinfo *cfi= &cfi_base[i]; 622 /* 623 * Ignore placeholder entries where cfi_index is less then 624 * zero. This will occur if the elf core dump code thinks 625 * it can save a vnode but winds up not being able to. 626 */ 627 if (cfi->cfi_index < 0) 628 continue; 629 630 /* 631 * Restore a saved file descriptor. If CKFIF_ISCKPTFD is 632 * set the descriptor represents the checkpoint file itself, 633 * probably due to the user calling sys_checkpoint(). We 634 * want to use the fp being used to restore the checkpoint 635 * instead of trying to restore the original filehandle. 636 */ 637 if (cfi->cfi_ckflags & CKFIF_ISCKPTFD) { 638 fhold(fp); 639 tempfp = fp; 640 error = 0; 641 } else { 642 error = ckpt_fhtovp(&cfi->cfi_fh, &vp); 643 if (error == 0) { 644 error = fp_vpopen(vp, OFLAGS(cfi->cfi_flags), 645 &tempfp); 646 if (error) 647 vput(vp); 648 } 649 } 650 if (error) 651 break; 652 tempfp->f_offset = cfi->cfi_offset; 653 654 /* 655 * If overwriting a descriptor close the old descriptor. This 656 * only occurs if the saved core saved descriptors that we 657 * have not already closed. 658 */ 659 if (cfi->cfi_index < p->p_fd->fd_nfiles && 660 (ofp = p->p_fd->fd_files[cfi->cfi_index].fp) != NULL) { 661 kern_close(cfi->cfi_index); 662 } 663 664 /* 665 * Allocate the descriptor we want. 666 */ 667 if (fdalloc(p, cfi->cfi_index, &fd) != 0) { 668 PRINTF(("can't currently restore fd: %d\n", 669 cfi->cfi_index)); 670 fp_close(fp); 671 goto done; 672 } 673 KKASSERT(fd == cfi->cfi_index); 674 fsetfd(p, tempfp, fd); 675 fdrop(tempfp); 676 cfi++; 677 PRINTF(("restoring %d\n", cfi->cfi_index)); 678 } 679 680 done: 681 if (cfi_base) 682 kfree(cfi_base, M_TEMP); 683 TRACE_EXIT; 684 return error; 685 } 686 687 static int 688 ckpt_freeze_proc(struct lwp *lp, struct file *fp) 689 { 690 struct proc *p = lp->lwp_proc; 691 rlim_t limit; 692 int error; 693 694 PRINTF(("calling generic_elf_coredump\n")); 695 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 696 if (limit) { 697 error = generic_elf_coredump(lp, SIGCKPT, fp, limit); 698 } else { 699 error = ERANGE; 700 } 701 return error; 702 } 703 704 int 705 sys_sys_checkpoint(struct sys_checkpoint_args *uap) 706 { 707 int error = 0; 708 struct lwp *lp = curthread->td_lwp; 709 struct proc *p = curthread->td_proc; 710 struct file *fp; 711 712 /* 713 * Only certain groups (to reduce our security exposure). -1 714 * allows any group. 715 */ 716 if (ckptgroup >= 0 && groupmember(ckptgroup, p->p_ucred) == 0) 717 return (EPERM); 718 719 /* 720 * For now we can only checkpoint the current process 721 */ 722 if (uap->pid != -1 && uap->pid != p->p_pid) 723 return (EINVAL); 724 725 switch (uap->type) { 726 case CKPT_FREEZE: 727 fp = NULL; 728 if (uap->fd == -1 && uap->pid == (pid_t)-1) 729 error = checkpoint_signal_handler(lp); 730 else if ((fp = holdfp(p->p_fd, uap->fd, FWRITE)) == NULL) 731 error = EBADF; 732 else 733 error = ckpt_freeze_proc(lp, fp); 734 if (fp) 735 fdrop(fp); 736 break; 737 case CKPT_THAW: 738 if (uap->pid != -1) 739 return EINVAL; 740 if ((fp = holdfp(p->p_fd, uap->fd, FREAD)) == NULL) 741 return EBADF; 742 uap->sysmsg_result = uap->retval; 743 error = ckpt_thaw_proc(lp, fp); 744 fdrop(fp); 745 break; 746 default: 747 error = EOPNOTSUPP; 748 break; 749 } 750 return error; 751 } 752 753 int 754 checkpoint_signal_handler(struct lwp *lp) 755 { 756 struct proc *p = lp->lwp_proc; 757 char *buf; 758 struct file *fp; 759 struct nlookupdata nd; 760 int error; 761 762 chptinuse++; 763 764 /* 765 * Being able to checkpoint an suid or sgid program is not a good 766 * idea. 767 */ 768 if (sugid_coredump == 0 && (p->p_flag & P_SUGID)) { 769 chptinuse--; 770 return (EPERM); 771 } 772 773 buf = ckpt_expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 774 if (buf == NULL) { 775 chptinuse--; 776 return (ENOMEM); 777 } 778 779 log(LOG_INFO, "pid %d (%s), uid %d: checkpointing to %s\n", 780 p->p_pid, p->p_comm, 781 (p->p_ucred ? p->p_ucred->cr_uid : -1), 782 buf); 783 784 PRINTF(("ckpt handler called, using '%s'\n", buf)); 785 786 /* 787 * Use the same safety flags that the coredump code uses. Remove 788 * any previous checkpoint file before writing out the new one in 789 * case we are re-checkpointing a program that had been checkpt 790 * restored. Otherwise we will corrupt the program space (which is 791 * made up of mmap()ings of the previous checkpoint file) while we 792 * write out the new one. 793 */ 794 error = nlookup_init(&nd, buf, UIO_SYSSPACE, 0); 795 if (error == 0) 796 error = kern_unlink(&nd); 797 nlookup_done(&nd); 798 error = fp_open(buf, O_WRONLY|O_CREAT|O_TRUNC|O_NOFOLLOW, 0600, &fp); 799 if (error == 0) { 800 error = ckpt_freeze_proc(lp, fp); 801 fp_close(fp); 802 } else { 803 kprintf("checkpoint failed with open - error: %d\n", error); 804 } 805 kfree(buf, M_TEMP); 806 chptinuse--; 807 return (error); 808 } 809 810 static char ckptfilename[MAXPATHLEN] = {"%N.ckpt"}; 811 SYSCTL_STRING(_kern, OID_AUTO, ckptfile, CTLFLAG_RW, ckptfilename, 812 sizeof(ckptfilename), "process checkpoint name format string"); 813 814 /* 815 * expand_name(name, uid, pid) 816 * Expand the name described in corefilename, using name, uid, and pid. 817 * corefilename is a kprintf-like string, with three format specifiers: 818 * %N name of process ("name") 819 * %P process id (pid) 820 * %U user id (uid) 821 * For example, "%N.core" is the default; they can be disabled completely 822 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 823 * This is controlled by the sysctl variable kern.corefile (see above). 824 * 825 * -- taken from the coredump code 826 */ 827 828 static 829 char * 830 ckpt_expand_name(const char *name, uid_t uid, pid_t pid) 831 { 832 char *temp; 833 char *bp; 834 char buf[11]; /* Buffer for pid/uid -- max 4B */ 835 int error; 836 int i; 837 int n; 838 char *format = ckptfilename; 839 size_t namelen; 840 841 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 842 if (temp == NULL) 843 return NULL; 844 namelen = strlen(name); 845 n = 0; 846 if (ckptfilename[0] != '/') { 847 if ((bp = kern_getcwd(temp, MAXPATHLEN - 1, &error)) == NULL) { 848 kfree(temp, M_TEMP); 849 return NULL; 850 } 851 n = strlen(bp); 852 bcopy(bp, temp, n + 1); /* normalize location of the path */ 853 temp[n++] = '/'; 854 temp[n] = '\0'; 855 } 856 for (i= 0; n < MAXPATHLEN && format[i]; i++) { 857 int l; 858 switch (format[i]) { 859 case '%': /* Format character */ 860 i++; 861 switch (format[i]) { 862 case '%': 863 temp[n++] = '%'; 864 break; 865 case 'N': /* process name */ 866 if ((n + namelen) > MAXPATHLEN) { 867 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 868 pid, name, uid, temp, name); 869 kfree(temp, M_TEMP); 870 return NULL; 871 } 872 memcpy(temp+n, name, namelen); 873 n += namelen; 874 break; 875 case 'P': /* process id */ 876 l = ksprintf(buf, "%u", pid); 877 if ((n + l) > MAXPATHLEN) { 878 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 879 pid, name, uid, temp, name); 880 kfree(temp, M_TEMP); 881 return NULL; 882 } 883 memcpy(temp+n, buf, l); 884 n += l; 885 break; 886 case 'U': /* user id */ 887 l = ksprintf(buf, "%u", uid); 888 if ((n + l) > MAXPATHLEN) { 889 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 890 pid, name, uid, temp, name); 891 kfree(temp, M_TEMP); 892 return NULL; 893 } 894 memcpy(temp+n, buf, l); 895 n += l; 896 break; 897 default: 898 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 899 } 900 break; 901 default: 902 temp[n++] = format[i]; 903 } 904 } 905 temp[n] = '\0'; 906 return temp; 907 } 908 909