Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_checkpoint.c
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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 27 #include <sys/types.h> 28 #include <sys/param.h> 29 #include <sys/proc.h> 30 #include <sys/module.h> 31 #include <sys/sysent.h> 32 #include <sys/kernel.h> 33 #include <sys/systm.h> 34 #include <sys/nlookup.h> 35 36 #include <sys/file.h> 37 #include <sys/fcntl.h> 38 #include <sys/signal.h> 39 #include <vm/vm_param.h> 40 #include <vm/vm.h> 41 #include <sys/imgact_elf.h> 42 #include <sys/procfs.h> 43 44 #include <sys/lock.h> 45 #include <vm/pmap.h> 46 #include <vm/vm_map.h> 47 #include <vm/vm_extern.h> 48 #include <sys/mman.h> 49 #include <sys/sysproto.h> 50 #include <sys/resource.h> 51 #include <sys/resourcevar.h> 52 #include <sys/malloc.h> 53 #include <sys/stat.h> 54 #include <sys/uio.h> 55 #include <sys/namei.h> 56 #include <sys/vnode.h> 57 #include <machine/inttypes.h> 58 #include <machine/limits.h> 59 #include <machine/frame.h> 60 #include <sys/signalvar.h> 61 #include <sys/syslog.h> 62 #include <sys/sysctl.h> 63 #include <machine/sigframe.h> 64 #include <sys/exec.h> 65 #include <sys/unistd.h> 66 #include <sys/time.h> 67 #include <sys/kern_syscall.h> 68 #include <sys/checkpoint.h> 69 #include <sys/mount.h> 70 #include <sys/ckpt.h> 71 72 #include <sys/mplock2.h> 73 #include <sys/file2.h> 74 75 static int elf_loadphdrs(struct file *fp, Elf_Phdr *phdr, int numsegs); 76 static int elf_getnotes(struct lwp *lp, struct file *fp, size_t notesz); 77 static int elf_demarshalnotes(void *src, prpsinfo_t *psinfo, 78 prstatus_t *status, prfpregset_t *fpregset, int nthreads); 79 static int elf_loadnotes(struct lwp *, prpsinfo_t *, prstatus_t *, 80 prfpregset_t *); 81 static int elf_getsigs(struct lwp *lp, struct file *fp); 82 static int elf_getfiles(struct lwp *lp, struct file *fp); 83 static int elf_gettextvp(struct proc *p, struct file *fp); 84 static char *ckpt_expand_name(const char *name, uid_t uid, pid_t pid); 85 86 static int ckptgroup = 0; /* wheel only, -1 for any group */ 87 SYSCTL_INT(_kern, OID_AUTO, ckptgroup, CTLFLAG_RW, &ckptgroup, 0, ""); 88 89 /* ref count to see how many processes that are being checkpointed */ 90 static int chptinuse = 0; 91 92 static __inline 93 int 94 read_check(struct file *fp, void *buf, size_t nbyte) 95 { 96 size_t nread; 97 int error; 98 99 PRINTF(("reading %zd bytes\n", nbyte)); 100 error = fp_read(fp, buf, nbyte, &nread, 1, UIO_SYSSPACE); 101 if (error) { 102 PRINTF(("read failed - %d", error)); 103 } else if (nread != nbyte) { 104 PRINTF(("wanted to read %zd - read %zd\n", nbyte, nread)); 105 error = EINVAL; 106 } 107 return error; 108 } 109 110 static int 111 elf_gethdr(struct file *fp, Elf_Ehdr *ehdr) 112 { 113 size_t nbyte = sizeof(Elf_Ehdr); 114 int error; 115 116 if ((error = read_check(fp, ehdr, nbyte)) != 0) 117 goto done; 118 if (!(ehdr->e_ehsize == sizeof(Elf_Ehdr))) { 119 PRINTF(("wrong elf header size: %d\n" 120 "expected size : %zd\n", 121 ehdr->e_ehsize, sizeof(Elf_Ehdr))); 122 return EINVAL; 123 } 124 if (!(ehdr->e_phentsize == sizeof(Elf_Phdr))) { 125 PRINTF(("wrong program header size: %d\n" 126 "expected size : %zd\n", 127 ehdr->e_phentsize, sizeof(Elf_Phdr))); 128 return EINVAL; 129 } 130 131 if (!(ehdr->e_ident[EI_MAG0] == ELFMAG0 && 132 ehdr->e_ident[EI_MAG1] == ELFMAG1 && 133 ehdr->e_ident[EI_MAG2] == ELFMAG2 && 134 ehdr->e_ident[EI_MAG3] == ELFMAG3 && 135 ehdr->e_ident[EI_CLASS] == ELF_CLASS && 136 ehdr->e_ident[EI_DATA] == ELF_DATA && 137 ehdr->e_ident[EI_VERSION] == EV_CURRENT && 138 ehdr->e_ident[EI_OSABI] == ELFOSABI_NONE && 139 ehdr->e_ident[EI_ABIVERSION] == 0)) { 140 PRINTF(("bad elf header\n there are %d segments\n", 141 ehdr->e_phnum)); 142 return EINVAL; 143 144 } 145 PRINTF(("Elf header size: %d\n", ehdr->e_ehsize)); 146 PRINTF(("Program header size: %d\n", ehdr->e_phentsize)); 147 PRINTF(("Number of Program headers: %d\n", ehdr->e_phnum)); 148 done: 149 return error; 150 } 151 152 static int 153 elf_getphdrs(struct file *fp, Elf_Phdr *phdr, size_t nbyte) 154 { 155 int i; 156 int error; 157 int nheaders = nbyte/sizeof(Elf_Phdr); 158 159 PRINTF(("reading phdrs section\n")); 160 if ((error = read_check(fp, phdr, nbyte)) != 0) 161 goto done; 162 PRINTF(("headers section:\n")); 163 for (i = 0; i < nheaders; i++) { 164 PRINTF(("entry type: %d\n", phdr[i].p_type)); 165 PRINTF(("file offset: %jd\n", (intmax_t)phdr[i].p_offset)); 166 PRINTF(("virt address: %p\n", (uint32_t *)phdr[i].p_vaddr)); 167 PRINTF(("file size: %jd\n", (intmax_t)phdr[i].p_filesz)); 168 PRINTF(("memory size: %jd\n", (intmax_t)phdr[i].p_memsz)); 169 PRINTF(("\n")); 170 } 171 done: 172 return error; 173 } 174 175 176 static int 177 elf_getnotes(struct lwp *lp, struct file *fp, size_t notesz) 178 { 179 int error; 180 int nthreads; 181 char *note; 182 prpsinfo_t *psinfo; 183 prstatus_t *status; 184 prfpregset_t *fpregset; 185 186 nthreads = (notesz - sizeof(prpsinfo_t))/(sizeof(prstatus_t) + 187 sizeof(prfpregset_t)); 188 PRINTF(("reading notes header nthreads=%d\n", nthreads)); 189 if (nthreads <= 0 || nthreads > CKPT_MAXTHREADS) 190 return EINVAL; 191 192 psinfo = kmalloc(sizeof(prpsinfo_t), M_TEMP, M_ZERO | M_WAITOK); 193 status = kmalloc(nthreads*sizeof(prstatus_t), M_TEMP, M_WAITOK); 194 fpregset = kmalloc(nthreads*sizeof(prfpregset_t), M_TEMP, M_WAITOK); 195 note = kmalloc(notesz, M_TEMP, M_WAITOK); 196 197 198 PRINTF(("reading notes section\n")); 199 if ((error = read_check(fp, note, notesz)) != 0) 200 goto done; 201 error = elf_demarshalnotes(note, psinfo, status, fpregset, nthreads); 202 if (error) 203 goto done; 204 /* fetch register state from notes */ 205 error = elf_loadnotes(lp, psinfo, status, fpregset); 206 done: 207 if (psinfo) 208 kfree(psinfo, M_TEMP); 209 if (status) 210 kfree(status, M_TEMP); 211 if (fpregset) 212 kfree(fpregset, M_TEMP); 213 if (note) 214 kfree(note, M_TEMP); 215 return error; 216 } 217 218 static int 219 ckpt_thaw_proc(struct lwp *lp, struct file *fp) 220 { 221 struct proc *p = lp->lwp_proc; 222 Elf_Phdr *phdr = NULL; 223 Elf_Ehdr *ehdr = NULL; 224 int error; 225 size_t nbyte; 226 227 TRACE_ENTER; 228 229 ehdr = kmalloc(sizeof(Elf_Ehdr), M_TEMP, M_ZERO | M_WAITOK); 230 231 if ((error = elf_gethdr(fp, ehdr)) != 0) 232 goto done; 233 nbyte = sizeof(Elf_Phdr) * ehdr->e_phnum; 234 phdr = kmalloc(nbyte, M_TEMP, M_WAITOK); 235 236 /* fetch description of program writable mappings */ 237 if ((error = elf_getphdrs(fp, phdr, nbyte)) != 0) 238 goto done; 239 240 /* fetch notes section containing register state */ 241 if ((error = elf_getnotes(lp, fp, phdr->p_filesz)) != 0) 242 goto done; 243 244 /* fetch program text vnodes */ 245 if ((error = elf_gettextvp(p, fp)) != 0) 246 goto done; 247 248 /* fetch signal disposition */ 249 if ((error = elf_getsigs(lp, fp)) != 0) { 250 kprintf("failure in recovering signals\n"); 251 goto done; 252 } 253 254 /* fetch open files */ 255 if ((error = elf_getfiles(lp, fp)) != 0) 256 goto done; 257 258 /* handle mappings last in case we are reading from a socket */ 259 error = elf_loadphdrs(fp, phdr, ehdr->e_phnum); 260 261 /* 262 * Set the textvp to the checkpoint file and mark the vnode so 263 * a future checkpointing of this checkpoint-restored program 264 * will copy out the contents of the mappings rather then trying 265 * to record the vnode info related to the checkpoint file, which 266 * is likely going to be destroyed when the program is re-checkpointed. 267 */ 268 if (error == 0 && fp->f_data && fp->f_type == DTYPE_VNODE) { 269 if (p->p_textvp) 270 vrele(p->p_textvp); 271 p->p_textvp = (struct vnode *)fp->f_data; 272 vsetflags(p->p_textvp, VCKPT); 273 vref(p->p_textvp); 274 } 275 done: 276 if (ehdr) 277 kfree(ehdr, M_TEMP); 278 if (phdr) 279 kfree(phdr, M_TEMP); 280 TRACE_EXIT; 281 return error; 282 } 283 284 static int 285 elf_loadnotes(struct lwp *lp, prpsinfo_t *psinfo, prstatus_t *status, 286 prfpregset_t *fpregset) 287 { 288 struct proc *p = lp->lwp_proc; 289 int error; 290 291 /* validate status and psinfo */ 292 TRACE_ENTER; 293 if (status->pr_version != PRSTATUS_VERSION || 294 status->pr_statussz != sizeof(prstatus_t) || 295 status->pr_gregsetsz != sizeof(gregset_t) || 296 status->pr_fpregsetsz != sizeof(fpregset_t) || 297 psinfo->pr_version != PRPSINFO_VERSION || 298 psinfo->pr_psinfosz != sizeof(prpsinfo_t)) { 299 PRINTF(("status check failed\n")); 300 error = EINVAL; 301 goto done; 302 } 303 /* XXX lwp handle more than one lwp*/ 304 if ((error = set_regs(lp, &status->pr_reg)) != 0) 305 goto done; 306 error = set_fpregs(lp, fpregset); 307 strlcpy(p->p_comm, psinfo->pr_fname, sizeof(p->p_comm)); 308 /* XXX psinfo->pr_psargs not yet implemented */ 309 done: 310 TRACE_EXIT; 311 return error; 312 } 313 314 static int 315 elf_getnote(void *src, size_t *off, const char *name, unsigned int type, 316 void **desc, size_t descsz) 317 { 318 Elf_Note note; 319 int error; 320 321 TRACE_ENTER; 322 if (src == NULL) { 323 error = EFAULT; 324 goto done; 325 } 326 bcopy((char *)src + *off, ¬e, sizeof note); 327 328 PRINTF(("at offset: %zd expected note of type: %d - got: %d\n", 329 *off, type, note.n_type)); 330 *off += sizeof note; 331 if (type != note.n_type) { 332 TRACE_ERR; 333 error = EINVAL; 334 goto done; 335 } 336 if (strncmp(name, (char *) src + *off, note.n_namesz) != 0) { 337 error = EINVAL; 338 goto done; 339 } 340 *off += roundup2(note.n_namesz, sizeof(Elf_Size)); 341 if (note.n_descsz != descsz) { 342 TRACE_ERR; 343 error = EINVAL; 344 goto done; 345 } 346 if (desc) 347 bcopy((char *)src + *off, *desc, note.n_descsz); 348 *off += roundup2(note.n_descsz, sizeof(Elf_Size)); 349 error = 0; 350 done: 351 TRACE_EXIT; 352 return error; 353 } 354 355 static int 356 elf_demarshalnotes(void *src, prpsinfo_t *psinfo, prstatus_t *status, 357 prfpregset_t *fpregset, int nthreads) 358 { 359 int i; 360 int error; 361 size_t off = 0; 362 363 TRACE_ENTER; 364 error = elf_getnote(src, &off, "CORE", NT_PRPSINFO, 365 (void **)&psinfo, sizeof(prpsinfo_t)); 366 if (error) 367 goto done; 368 error = elf_getnote(src, &off, "CORE", NT_PRSTATUS, 369 (void **)&status, sizeof(prstatus_t)); 370 if (error) 371 goto done; 372 error = elf_getnote(src, &off, "CORE", NT_FPREGSET, 373 (void **)&fpregset, sizeof(prfpregset_t)); 374 if (error) 375 goto done; 376 377 /* 378 * The remaining portion needs to be an integer multiple 379 * of prstatus_t and prfpregset_t 380 */ 381 for (i = 0 ; i < nthreads - 1; i++) { 382 status++; fpregset++; 383 error = elf_getnote(src, &off, "CORE", NT_PRSTATUS, 384 (void **)&status, sizeof (prstatus_t)); 385 if (error) 386 goto done; 387 error = elf_getnote(src, &off, "CORE", NT_FPREGSET, 388 (void **)&fpregset, sizeof(prfpregset_t)); 389 if (error) 390 goto done; 391 } 392 393 done: 394 TRACE_EXIT; 395 return error; 396 } 397 398 399 static int 400 mmap_phdr(struct file *fp, Elf_Phdr *phdr) 401 { 402 int error; 403 size_t len; 404 int prot; 405 void *addr; 406 int flags; 407 off_t pos; 408 409 TRACE_ENTER; 410 pos = phdr->p_offset; 411 len = phdr->p_filesz; 412 addr = (void *)phdr->p_vaddr; 413 flags = MAP_FIXED | MAP_NOSYNC | MAP_PRIVATE; 414 prot = 0; 415 if (phdr->p_flags & PF_R) 416 prot |= PROT_READ; 417 if (phdr->p_flags & PF_W) 418 prot |= PROT_WRITE; 419 if (phdr->p_flags & PF_X) 420 prot |= PROT_EXEC; 421 if ((error = fp_mmap(addr, len, prot, flags, fp, pos, &addr)) != 0) { 422 PRINTF(("mmap failed: %d\n", error); ); 423 } 424 PRINTF(("map @%08"PRIxPTR"-%08"PRIxPTR" fileoff %08x-%08x\n", (uintptr_t)addr, 425 (uintptr_t)((char *)addr + len), (int)pos, (int)(pos + len))); 426 TRACE_EXIT; 427 return error; 428 } 429 430 /* 431 * Load memory mapped segments. The segments are backed by the checkpoint 432 * file. 433 */ 434 static int 435 elf_loadphdrs(struct file *fp, Elf_Phdr *phdr, int numsegs) 436 { 437 int i; 438 int error = 0; 439 440 TRACE_ENTER; 441 for (i = 1; i < numsegs; i++) { 442 if ((error = mmap_phdr(fp, &phdr[i])) != 0) 443 break; 444 } 445 TRACE_EXIT; 446 return error; 447 } 448 449 static int 450 elf_getsigs(struct lwp *lp, struct file *fp) 451 { 452 struct proc *p = lp->lwp_proc; 453 int error; 454 struct ckpt_siginfo *csi; 455 456 TRACE_ENTER; 457 csi = kmalloc(sizeof(struct ckpt_siginfo), M_TEMP, M_ZERO | M_WAITOK); 458 if ((error = read_check(fp, csi, sizeof(struct ckpt_siginfo))) != 0) 459 goto done; 460 461 if (csi->csi_ckptpisz != sizeof(struct ckpt_siginfo)) { 462 TRACE_ERR; 463 error = EINVAL; 464 goto done; 465 } 466 bcopy(&csi->csi_sigacts, p->p_sigacts, sizeof(struct sigacts)); 467 bcopy(&csi->csi_itimerval, &p->p_realtimer, sizeof(struct itimerval)); 468 SIG_CANTMASK(csi->csi_sigmask); 469 /* XXX lwp handle more than one lwp */ 470 bcopy(&csi->csi_sigmask, &lp->lwp_sigmask, sizeof(sigset_t)); 471 p->p_sigparent = csi->csi_sigparent; 472 done: 473 if (csi) 474 kfree(csi, M_TEMP); 475 TRACE_EXIT; 476 return error; 477 } 478 479 /* 480 * Returns a locked, refd vnode 481 */ 482 static int 483 ckpt_fhtovp(fhandle_t *fh, struct vnode **vpp) 484 { 485 struct mount *mp; 486 int error; 487 488 TRACE_ENTER; 489 mp = vfs_getvfs(&fh->fh_fsid); 490 491 if (!mp) { 492 TRACE_ERR; 493 PRINTF(("failed to get mount - ESTALE\n")); 494 TRACE_EXIT; 495 return ESTALE; 496 } 497 error = VFS_FHTOVP(mp, NULL, &fh->fh_fid, vpp); 498 if (error) { 499 PRINTF(("failed with: %d\n", error)); 500 TRACE_ERR; 501 TRACE_EXIT; 502 return error; 503 } 504 TRACE_EXIT; 505 return 0; 506 } 507 508 static int 509 mmap_vp(struct vn_hdr *vnh) 510 { 511 struct vnode *vp; 512 Elf_Phdr *phdr; 513 struct file *fp; 514 int error; 515 TRACE_ENTER; 516 517 phdr = &vnh->vnh_phdr; 518 519 if ((error = ckpt_fhtovp(&vnh->vnh_fh, &vp)) != 0) 520 return error; 521 /* 522 * XXX O_RDONLY -> or O_RDWR if file is PROT_WRITE, MAP_SHARED 523 */ 524 if ((error = fp_vpopen(vp, O_RDONLY, &fp)) != 0) { 525 vput(vp); 526 return error; 527 } 528 error = mmap_phdr(fp, phdr); 529 fp_close(fp); 530 TRACE_EXIT; 531 return error; 532 } 533 534 535 static int 536 elf_gettextvp(struct proc *p, struct file *fp) 537 { 538 int i; 539 int error; 540 int vpcount; 541 struct ckpt_vminfo vminfo; 542 struct vn_hdr *vnh = NULL; 543 544 TRACE_ENTER; 545 if ((error = read_check(fp, &vminfo, sizeof(vminfo))) != 0) 546 goto done; 547 if (vminfo.cvm_dsize < 0 || 548 vminfo.cvm_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur || 549 vminfo.cvm_tsize < 0 || 550 (u_quad_t)vminfo.cvm_tsize > maxtsiz || 551 vminfo.cvm_daddr >= (caddr_t)VM_MAX_USER_ADDRESS || 552 vminfo.cvm_taddr >= (caddr_t)VM_MAX_USER_ADDRESS 553 ) { 554 error = ERANGE; 555 goto done; 556 } 557 558 vmspace_exec(p, NULL); 559 p->p_vmspace->vm_daddr = vminfo.cvm_daddr; 560 p->p_vmspace->vm_dsize = vminfo.cvm_dsize; 561 p->p_vmspace->vm_taddr = vminfo.cvm_taddr; 562 p->p_vmspace->vm_tsize = vminfo.cvm_tsize; 563 if ((error = read_check(fp, &vpcount, sizeof(int))) != 0) 564 goto done; 565 vnh = kmalloc(sizeof(struct vn_hdr) * vpcount, M_TEMP, M_WAITOK); 566 if ((error = read_check(fp, vnh, sizeof(struct vn_hdr)*vpcount)) != 0) 567 goto done; 568 for (i = 0; i < vpcount; i++) { 569 if ((error = mmap_vp(&vnh[i])) != 0) 570 goto done; 571 } 572 573 done: 574 if (vnh) 575 kfree(vnh, M_TEMP); 576 TRACE_EXIT; 577 return error; 578 } 579 580 581 582 /* place holder */ 583 static int 584 elf_getfiles(struct lwp *lp, struct file *fp) 585 { 586 int error; 587 int i; 588 int filecount; 589 int fd; 590 struct ckpt_filehdr filehdr; 591 struct ckpt_fileinfo *cfi_base = NULL; 592 struct filedesc *fdp = lp->lwp_proc->p_fd; 593 struct vnode *vp; 594 struct file *tempfp; 595 struct file *ofp; 596 597 TRACE_ENTER; 598 if ((error = read_check(fp, &filehdr, sizeof(filehdr))) != 0) 599 goto done; 600 filecount = filehdr.cfh_nfiles; 601 cfi_base = kmalloc(filecount*sizeof(struct ckpt_fileinfo), M_TEMP, M_WAITOK); 602 error = read_check(fp, cfi_base, filecount*sizeof(struct ckpt_fileinfo)); 603 if (error) 604 goto done; 605 606 /* 607 * Close all file descriptors >= 3. These descriptors are from the 608 * checkpt(1) program itself and should not be retained. 609 * 610 * XXX we need a flag so a checkpoint restore can opt to supply the 611 * descriptors, or the non-regular-file descripors. 612 */ 613 for (i = 3; i < fdp->fd_nfiles; ++i) 614 kern_close(i); 615 616 /* 617 * Scan files to load 618 */ 619 for (i = 0; i < filecount; i++) { 620 struct ckpt_fileinfo *cfi= &cfi_base[i]; 621 /* 622 * Ignore placeholder entries where cfi_index is less then 623 * zero. This will occur if the elf core dump code thinks 624 * it can save a vnode but winds up not being able to. 625 */ 626 if (cfi->cfi_index < 0) 627 continue; 628 629 /* 630 * Restore a saved file descriptor. If CKFIF_ISCKPTFD is 631 * set the descriptor represents the checkpoint file itself, 632 * probably due to the user calling sys_checkpoint(). We 633 * want to use the fp being used to restore the checkpoint 634 * instead of trying to restore the original filehandle. 635 */ 636 if (cfi->cfi_ckflags & CKFIF_ISCKPTFD) { 637 fhold(fp); 638 tempfp = fp; 639 error = 0; 640 } else { 641 error = ckpt_fhtovp(&cfi->cfi_fh, &vp); 642 if (error == 0) { 643 error = fp_vpopen(vp, OFLAGS(cfi->cfi_flags), 644 &tempfp); 645 if (error) 646 vput(vp); 647 } 648 } 649 if (error) 650 break; 651 tempfp->f_offset = cfi->cfi_offset; 652 653 /* 654 * If overwriting a descriptor close the old descriptor. This 655 * only occurs if the saved core saved descriptors that we 656 * have not already closed. 657 */ 658 if (cfi->cfi_index < fdp->fd_nfiles && 659 (ofp = fdp->fd_files[cfi->cfi_index].fp) != NULL) { 660 kern_close(cfi->cfi_index); 661 } 662 663 /* 664 * Allocate the descriptor we want. 665 */ 666 if (fdalloc(lp->lwp_proc, cfi->cfi_index, &fd) != 0) { 667 PRINTF(("can't currently restore fd: %d\n", 668 cfi->cfi_index)); 669 fp_close(fp); 670 goto done; 671 } 672 KKASSERT(fd == cfi->cfi_index); 673 fsetfd(fdp, tempfp, fd); 674 fdrop(tempfp); 675 cfi++; 676 PRINTF(("restoring %d\n", cfi->cfi_index)); 677 } 678 679 done: 680 if (cfi_base) 681 kfree(cfi_base, M_TEMP); 682 TRACE_EXIT; 683 return error; 684 } 685 686 static int 687 ckpt_freeze_proc(struct lwp *lp, struct file *fp) 688 { 689 struct proc *p = lp->lwp_proc; 690 rlim_t limit; 691 int error; 692 693 lwkt_gettoken(&p->p_token); /* needed for proc_*() calls */ 694 695 PRINTF(("calling generic_elf_coredump\n")); 696 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 697 if (limit) { 698 proc_stop(p); 699 while (p->p_nstopped < p->p_nthreads - 1) 700 tsleep(&p->p_nstopped, 0, "freeze", 1); 701 error = generic_elf_coredump(lp, SIGCKPT, fp, limit); 702 proc_unstop(p); 703 } else { 704 error = ERANGE; 705 } 706 lwkt_reltoken(&p->p_token); 707 return error; 708 } 709 710 /* 711 * MPALMOSTSAFE 712 */ 713 int 714 sys_sys_checkpoint(struct sys_checkpoint_args *uap) 715 { 716 int error = 0; 717 struct thread *td = curthread; 718 struct proc *p = td->td_proc; 719 struct filedesc *fdp = p->p_fd; 720 struct file *fp; 721 722 /* 723 * Only certain groups (to reduce our security exposure). -1 724 * allows any group. 725 */ 726 if (ckptgroup >= 0 && groupmember(ckptgroup, td->td_ucred) == 0) 727 return (EPERM); 728 729 /* 730 * For now we can only checkpoint the current process 731 */ 732 if (uap->pid != -1 && uap->pid != p->p_pid) 733 return (EINVAL); 734 735 get_mplock(); 736 737 switch (uap->type) { 738 case CKPT_FREEZE: 739 fp = NULL; 740 if (uap->fd == -1 && uap->pid == (pid_t)-1) 741 error = checkpoint_signal_handler(td->td_lwp); 742 else if ((fp = holdfp(fdp, uap->fd, FWRITE)) == NULL) 743 error = EBADF; 744 else 745 error = ckpt_freeze_proc(td->td_lwp, fp); 746 if (fp) 747 fdrop(fp); 748 break; 749 case CKPT_THAW: 750 if (uap->pid != -1) { 751 error = EINVAL; 752 break; 753 } 754 if ((fp = holdfp(fdp, uap->fd, FREAD)) == NULL) { 755 error = EBADF; 756 break; 757 } 758 uap->sysmsg_result = uap->retval; 759 error = ckpt_thaw_proc(td->td_lwp, fp); 760 fdrop(fp); 761 break; 762 default: 763 error = EOPNOTSUPP; 764 break; 765 } 766 rel_mplock(); 767 return error; 768 } 769 770 int 771 checkpoint_signal_handler(struct lwp *lp) 772 { 773 struct thread *td = lp->lwp_thread; 774 struct proc *p = lp->lwp_proc; 775 char *buf; 776 struct file *fp; 777 struct nlookupdata nd; 778 int error; 779 780 chptinuse++; 781 782 /* 783 * Being able to checkpoint an suid or sgid program is not a good 784 * idea. 785 */ 786 if (sugid_coredump == 0 && (p->p_flags & P_SUGID)) { 787 chptinuse--; 788 return (EPERM); 789 } 790 791 buf = ckpt_expand_name(p->p_comm, td->td_ucred->cr_uid, p->p_pid); 792 if (buf == NULL) { 793 chptinuse--; 794 return (ENOMEM); 795 } 796 797 log(LOG_INFO, "pid %d (%s), uid %d: checkpointing to %s\n", 798 p->p_pid, p->p_comm, 799 (td->td_ucred ? td->td_ucred->cr_uid : -1), 800 buf); 801 802 PRINTF(("ckpt handler called, using '%s'\n", buf)); 803 804 /* 805 * Use the same safety flags that the coredump code uses. Remove 806 * any previous checkpoint file before writing out the new one in 807 * case we are re-checkpointing a program that had been checkpt 808 * restored. Otherwise we will corrupt the program space (which is 809 * made up of mmap()ings of the previous checkpoint file) while we 810 * write out the new one. 811 */ 812 error = nlookup_init(&nd, buf, UIO_SYSSPACE, 0); 813 if (error == 0) 814 error = kern_unlink(&nd); 815 nlookup_done(&nd); 816 error = fp_open(buf, O_WRONLY|O_CREAT|O_TRUNC|O_NOFOLLOW, 0600, &fp); 817 if (error == 0) { 818 error = ckpt_freeze_proc(lp, fp); 819 fp_close(fp); 820 } else { 821 kprintf("checkpoint failed with open - error: %d\n", error); 822 } 823 kfree(buf, M_TEMP); 824 chptinuse--; 825 return (error); 826 } 827 828 static char ckptfilename[MAXPATHLEN] = {"%N.ckpt"}; 829 SYSCTL_STRING(_kern, OID_AUTO, ckptfile, CTLFLAG_RW, ckptfilename, 830 sizeof(ckptfilename), "process checkpoint name format string"); 831 832 /* 833 * expand_name(name, uid, pid) 834 * Expand the name described in corefilename, using name, uid, and pid. 835 * corefilename is a kprintf-like string, with three format specifiers: 836 * %N name of process ("name") 837 * %P process id (pid) 838 * %U user id (uid) 839 * For example, "%N.core" is the default; they can be disabled completely 840 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 841 * This is controlled by the sysctl variable kern.corefile (see above). 842 * 843 * -- taken from the coredump code 844 */ 845 846 static 847 char * 848 ckpt_expand_name(const char *name, uid_t uid, pid_t pid) 849 { 850 char *temp; 851 char *bp; 852 char buf[11]; /* Buffer for pid/uid -- max 4B */ 853 int error; 854 int i; 855 int n; 856 char *format = ckptfilename; 857 size_t namelen; 858 859 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 860 if (temp == NULL) 861 return NULL; 862 namelen = strlen(name); 863 n = 0; 864 if (ckptfilename[0] != '/') { 865 if ((bp = kern_getcwd(temp, MAXPATHLEN - 1, &error)) == NULL) { 866 kfree(temp, M_TEMP); 867 return NULL; 868 } 869 n = strlen(bp); 870 bcopy(bp, temp, n + 1); /* normalize location of the path */ 871 temp[n++] = '/'; 872 temp[n] = '\0'; 873 } 874 for (i= 0; n < MAXPATHLEN && format[i]; i++) { 875 int l; 876 switch (format[i]) { 877 case '%': /* Format character */ 878 i++; 879 switch (format[i]) { 880 case '%': 881 temp[n++] = '%'; 882 break; 883 case 'N': /* process name */ 884 if ((n + namelen) > MAXPATHLEN) { 885 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 886 pid, name, uid, temp, name); 887 kfree(temp, M_TEMP); 888 return NULL; 889 } 890 memcpy(temp+n, name, namelen); 891 n += namelen; 892 break; 893 case 'P': /* process id */ 894 l = ksprintf(buf, "%u", pid); 895 if ((n + l) > MAXPATHLEN) { 896 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 897 pid, name, uid, temp, name); 898 kfree(temp, M_TEMP); 899 return NULL; 900 } 901 memcpy(temp+n, buf, l); 902 n += l; 903 break; 904 case 'U': /* user id */ 905 l = ksprintf(buf, "%u", uid); 906 if ((n + l) > MAXPATHLEN) { 907 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 908 pid, name, uid, temp, name); 909 kfree(temp, M_TEMP); 910 return NULL; 911 } 912 memcpy(temp+n, buf, l); 913 n += l; 914 break; 915 default: 916 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 917 } 918 break; 919 default: 920 temp[n++] = format[i]; 921 } 922 } 923 temp[n] = '\0'; 924 return temp; 925 } 926
Cache object: b3a7f6ed8a1f169dd40184339bb35326
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