sftp-server.c

   1 /* $OpenBSD: sftp-server.c,v 1.88 2009/10/17 12:10:39 sobrado Exp $ */
   2 /*
   3  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #include "includes.h"
  19
  20 #include <sys/types.h>
  21 #include <sys/param.h>
  22 #include <sys/stat.h>
  23 #ifdef HAVE_SYS_TIME_H
  24 # include <sys/time.h>
  25 #endif
  26 #ifdef HAVE_SYS_MOUNT_H
  27 #include <sys/mount.h>
  28 #endif
  29 #ifdef HAVE_SYS_STATVFS_H
  30 #include <sys/statvfs.h>
  31 #endif
  32
  33 #include <dirent.h>
  34 #include <errno.h>
  35 #include <fcntl.h>
  36 #include <pwd.h>
  37 #include <stdlib.h>
  38 #include <stdio.h>
  39 #include <string.h>
  40 #include <pwd.h>
  41 #include <time.h>
  42 #include <unistd.h>
  43 #include <stdarg.h>
  44
  45 #include "xmalloc.h"
  46 #include "buffer.h"
  47 #include "log.h"
  48 #include "misc.h"
  49 #include "uidswap.h"
  50
  51 #include "sftp.h"
  52 #include "sftp-common.h"
  53
  54 /* helper */
  55 #define get_int64()                     buffer_get_int64(&iqueue);
  56 #define get_int()                       buffer_get_int(&iqueue);
  57 #define get_string(lenp)                buffer_get_string(&iqueue, lenp);
  58
  59 /* Our verbosity */
  60 LogLevel log_level = SYSLOG_LEVEL_ERROR;
  61
  62 /* Our client */
  63 struct passwd *pw = NULL;
  64 char *client_addr = NULL;
  65
  66 /* input and output queue */
  67 Buffer iqueue;
  68 Buffer oqueue;
  69
  70 /* Version of client */
  71 int version;
  72
  73 /* portable attributes, etc. */
  74
  75 typedef struct Stat Stat;
  76
  77 struct Stat {
  78         char *name;
  79         char *long_name;
  80         Attrib attrib;
  81 };
  82
  83 static int
  84 errno_to_portable(int unixerrno)
  85 {
  86         int ret = 0;
  87
  88         switch (unixerrno) {
  89         case 0:
  90                 ret = SSH2_FX_OK;
  91                 break;
  92         case ENOENT:
  93         case ENOTDIR:
  94         case EBADF:
  95         case ELOOP:
  96                 ret = SSH2_FX_NO_SUCH_FILE;
  97                 break;
  98         case EPERM:
  99         case EACCES:
 100         case EFAULT:
 101                 ret = SSH2_FX_PERMISSION_DENIED;
 102                 break;
 103         case ENAMETOOLONG:
 104         case EINVAL:
 105                 ret = SSH2_FX_BAD_MESSAGE;
 106                 break;
 107         case ENOSYS:
 108                 ret = SSH2_FX_OP_UNSUPPORTED;
 109                 break;
 110         default:
 111                 ret = SSH2_FX_FAILURE;
 112                 break;
 113         }
 114         return ret;
 115 }
 116
 117 static int
 118 flags_from_portable(int pflags)
 119 {
 120         int flags = 0;
 121
 122         if ((pflags & SSH2_FXF_READ) &&
 123             (pflags & SSH2_FXF_WRITE)) {
 124                 flags = O_RDWR;
 125         } else if (pflags & SSH2_FXF_READ) {
 126                 flags = O_RDONLY;
 127         } else if (pflags & SSH2_FXF_WRITE) {
 128                 flags = O_WRONLY;
 129         }
 130         if (pflags & SSH2_FXF_CREAT)
 131                 flags |= O_CREAT;
 132         if (pflags & SSH2_FXF_TRUNC)
 133                 flags |= O_TRUNC;
 134         if (pflags & SSH2_FXF_EXCL)
 135                 flags |= O_EXCL;
 136         return flags;
 137 }
 138
 139 static const char *
 140 string_from_portable(int pflags)
 141 {
 142         static char ret[128];
 143
 144         *ret = '\0';
 145
 146 #define PAPPEND(str)    {                               \
 147                 if (*ret != '\0')                       \
 148                         strlcat(ret, ",", sizeof(ret)); \
 149                 strlcat(ret, str, sizeof(ret));         \
 150         }
 151
 152         if (pflags & SSH2_FXF_READ)
 153                 PAPPEND("READ")
 154         if (pflags & SSH2_FXF_WRITE)
 155                 PAPPEND("WRITE")
 156         if (pflags & SSH2_FXF_CREAT)
 157                 PAPPEND("CREATE")
 158         if (pflags & SSH2_FXF_TRUNC)
 159                 PAPPEND("TRUNCATE")
 160         if (pflags & SSH2_FXF_EXCL)
 161                 PAPPEND("EXCL")
 162
 163         return ret;
 164 }
 165
 166 static Attrib *
 167 get_attrib(void)
 168 {
 169         return decode_attrib(&iqueue);
 170 }
 171
 172 /* handle handles */
 173
 174 typedef struct Handle Handle;
 175 struct Handle {
 176         int use;
 177         DIR *dirp;
 178         int fd;
 179         char *name;
 180         u_int64_t bytes_read, bytes_write;
 181         int next_unused;
 182 };
 183
 184 enum {
 185         HANDLE_UNUSED,
 186         HANDLE_DIR,
 187         HANDLE_FILE
 188 };
 189
 190 Handle *handles = NULL;
 191 u_int num_handles = 0;
 192 int first_unused_handle = -1;
 193
 194 static void handle_unused(int i)
 195 {
 196         handles[i].use = HANDLE_UNUSED;
 197         handles[i].next_unused = first_unused_handle;
 198         first_unused_handle = i;
 199 }
 200
 201 static int
 202 handle_new(int use, const char *name, int fd, DIR *dirp)
 203 {
 204         int i;
 205
 206         if (first_unused_handle == -1) {
 207                 if (num_handles + 1 <= num_handles)
 208                         return -1;
 209                 num_handles++;
 210                 handles = xrealloc(handles, num_handles, sizeof(Handle));
 211                 handle_unused(num_handles - 1);
 212         }
 213
 214         i = first_unused_handle;
 215         first_unused_handle = handles[i].next_unused;
 216
 217         handles[i].use = use;
 218         handles[i].dirp = dirp;
 219         handles[i].fd = fd;
 220         handles[i].name = xstrdup(name);
 221         handles[i].bytes_read = handles[i].bytes_write = 0;
 222
 223         return i;
 224 }
 225
 226 static int
 227 handle_is_ok(int i, int type)
 228 {
 229         return i >= 0 && (u_int)i < num_handles && handles[i].use == type;
 230 }
 231
 232 static int
 233 handle_to_string(int handle, char **stringp, int *hlenp)
 234 {
 235         if (stringp == NULL || hlenp == NULL)
 236                 return -1;
 237         *stringp = xmalloc(sizeof(int32_t));
 238         put_u32(*stringp, handle);
 239         *hlenp = sizeof(int32_t);
 240         return 0;
 241 }
 242
 243 static int
 244 handle_from_string(const char *handle, u_int hlen)
 245 {
 246         int val;
 247
 248         if (hlen != sizeof(int32_t))
 249                 return -1;
 250         val = get_u32(handle);
 251         if (handle_is_ok(val, HANDLE_FILE) ||
 252             handle_is_ok(val, HANDLE_DIR))
 253                 return val;
 254         return -1;
 255 }
 256
 257 static char *
 258 handle_to_name(int handle)
 259 {
 260         if (handle_is_ok(handle, HANDLE_DIR)||
 261             handle_is_ok(handle, HANDLE_FILE))
 262                 return handles[handle].name;
 263         return NULL;
 264 }
 265
 266 static DIR *
 267 handle_to_dir(int handle)
 268 {
 269         if (handle_is_ok(handle, HANDLE_DIR))
 270                 return handles[handle].dirp;
 271         return NULL;
 272 }
 273
 274 static int
 275 handle_to_fd(int handle)
 276 {
 277         if (handle_is_ok(handle, HANDLE_FILE))
 278                 return handles[handle].fd;
 279         return -1;
 280 }
 281
 282 static void
 283 handle_update_read(int handle, ssize_t bytes)
 284 {
 285         if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
 286                 handles[handle].bytes_read += bytes;
 287 }
 288
 289 static void
 290 handle_update_write(int handle, ssize_t bytes)
 291 {
 292         if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
 293                 handles[handle].bytes_write += bytes;
 294 }
 295
 296 static u_int64_t
 297 handle_bytes_read(int handle)
 298 {
 299         if (handle_is_ok(handle, HANDLE_FILE))
 300                 return (handles[handle].bytes_read);
 301         return 0;
 302 }
 303
 304 static u_int64_t
 305 handle_bytes_write(int handle)
 306 {
 307         if (handle_is_ok(handle, HANDLE_FILE))
 308                 return (handles[handle].bytes_write);
 309         return 0;
 310 }
 311
 312 static int
 313 handle_close(int handle)
 314 {
 315         int ret = -1;
 316
 317         if (handle_is_ok(handle, HANDLE_FILE)) {
 318                 ret = close(handles[handle].fd);
 319                 xfree(handles[handle].name);
 320                 handle_unused(handle);
 321         } else if (handle_is_ok(handle, HANDLE_DIR)) {
 322                 ret = closedir(handles[handle].dirp);
 323                 xfree(handles[handle].name);
 324                 handle_unused(handle);
 325         } else {
 326                 errno = ENOENT;
 327         }
 328         return ret;
 329 }
 330
 331 static void
 332 handle_log_close(int handle, char *emsg)
 333 {
 334         if (handle_is_ok(handle, HANDLE_FILE)) {
 335                 logit("%s%sclose \"%s\" bytes read %llu written %llu",
 336                     emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
 337                     handle_to_name(handle),
 338                     (unsigned long long)handle_bytes_read(handle),
 339                     (unsigned long long)handle_bytes_write(handle));
 340         } else {
 341                 logit("%s%sclosedir \"%s\"",
 342                     emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
 343                     handle_to_name(handle));
 344         }
 345 }
 346
 347 static void
 348 handle_log_exit(void)
 349 {
 350         u_int i;
 351
 352         for (i = 0; i < num_handles; i++)
 353                 if (handles[i].use != HANDLE_UNUSED)
 354                         handle_log_close(i, "forced");
 355 }
 356
 357 static int
 358 get_handle(void)
 359 {
 360         char *handle;
 361         int val = -1;
 362         u_int hlen;
 363
 364         handle = get_string(&hlen);
 365         if (hlen < 256)
 366                 val = handle_from_string(handle, hlen);
 367         xfree(handle);
 368         return val;
 369 }
 370
 371 /* send replies */
 372
 373 static void
 374 send_msg(Buffer *m)
 375 {
 376         int mlen = buffer_len(m);
 377
 378         buffer_put_int(&oqueue, mlen);
 379         buffer_append(&oqueue, buffer_ptr(m), mlen);
 380         buffer_consume(m, mlen);
 381 }
 382
 383 static const char *
 384 status_to_message(u_int32_t status)
 385 {
 386         const char *status_messages[] = {
 387                 "Success",                      /* SSH_FX_OK */
 388                 "End of file",                  /* SSH_FX_EOF */
 389                 "No such file",                 /* SSH_FX_NO_SUCH_FILE */
 390                 "Permission denied",            /* SSH_FX_PERMISSION_DENIED */
 391                 "Failure",                      /* SSH_FX_FAILURE */
 392                 "Bad message",                  /* SSH_FX_BAD_MESSAGE */
 393                 "No connection",                /* SSH_FX_NO_CONNECTION */
 394                 "Connection lost",              /* SSH_FX_CONNECTION_LOST */
 395                 "Operation unsupported",        /* SSH_FX_OP_UNSUPPORTED */
 396                 "Unknown error"                 /* Others */
 397         };
 398         return (status_messages[MIN(status,SSH2_FX_MAX)]);
 399 }
 400
 401 static void
 402 send_status(u_int32_t id, u_int32_t status)
 403 {
 404         Buffer msg;
 405
 406         debug3("request %u: sent status %u", id, status);
 407         if (log_level > SYSLOG_LEVEL_VERBOSE ||
 408             (status != SSH2_FX_OK && status != SSH2_FX_EOF))
 409                 logit("sent status %s", status_to_message(status));
 410         buffer_init(&msg);
 411         buffer_put_char(&msg, SSH2_FXP_STATUS);
 412         buffer_put_int(&msg, id);
 413         buffer_put_int(&msg, status);
 414         if (version >= 3) {
 415                 buffer_put_cstring(&msg, status_to_message(status));
 416                 buffer_put_cstring(&msg, "");
 417         }
 418         send_msg(&msg);
 419         buffer_free(&msg);
 420 }
 421 static void
 422 send_data_or_handle(char type, u_int32_t id, const char *data, int dlen)
 423 {
 424         Buffer msg;
 425
 426         buffer_init(&msg);
 427         buffer_put_char(&msg, type);
 428         buffer_put_int(&msg, id);
 429         buffer_put_string(&msg, data, dlen);
 430         send_msg(&msg);
 431         buffer_free(&msg);
 432 }
 433
 434 static void
 435 send_data(u_int32_t id, const char *data, int dlen)
 436 {
 437         debug("request %u: sent data len %d", id, dlen);
 438         send_data_or_handle(SSH2_FXP_DATA, id, data, dlen);
 439 }
 440
 441 static void
 442 send_handle(u_int32_t id, int handle)
 443 {
 444         char *string;
 445         int hlen;
 446
 447         handle_to_string(handle, &string, &hlen);
 448         debug("request %u: sent handle handle %d", id, handle);
 449         send_data_or_handle(SSH2_FXP_HANDLE, id, string, hlen);
 450         xfree(string);
 451 }
 452
 453 static void
 454 send_names(u_int32_t id, int count, const Stat *stats)
 455 {
 456         Buffer msg;
 457         int i;
 458
 459         buffer_init(&msg);
 460         buffer_put_char(&msg, SSH2_FXP_NAME);
 461         buffer_put_int(&msg, id);
 462         buffer_put_int(&msg, count);
 463         debug("request %u: sent names count %d", id, count);
 464         for (i = 0; i < count; i++) {
 465                 buffer_put_cstring(&msg, stats[i].name);
 466                 buffer_put_cstring(&msg, stats[i].long_name);
 467                 encode_attrib(&msg, &stats[i].attrib);
 468         }
 469         send_msg(&msg);
 470         buffer_free(&msg);
 471 }
 472
 473 static void
 474 send_attrib(u_int32_t id, const Attrib *a)
 475 {
 476         Buffer msg;
 477
 478         debug("request %u: sent attrib have 0x%x", id, a->flags);
 479         buffer_init(&msg);
 480         buffer_put_char(&msg, SSH2_FXP_ATTRS);
 481         buffer_put_int(&msg, id);
 482         encode_attrib(&msg, a);
 483         send_msg(&msg);
 484         buffer_free(&msg);
 485 }
 486
 487 static void
 488 send_statvfs(u_int32_t id, struct statvfs *st)
 489 {
 490         Buffer msg;
 491         u_int64_t flag;
 492
 493         flag = (st->f_flag & ST_RDONLY) ? SSH2_FXE_STATVFS_ST_RDONLY : 0;
 494         flag |= (st->f_flag & ST_NOSUID) ? SSH2_FXE_STATVFS_ST_NOSUID : 0;
 495
 496         buffer_init(&msg);
 497         buffer_put_char(&msg, SSH2_FXP_EXTENDED_REPLY);
 498         buffer_put_int(&msg, id);
 499         buffer_put_int64(&msg, st->f_bsize);
 500         buffer_put_int64(&msg, st->f_frsize);
 501         buffer_put_int64(&msg, st->f_blocks);
 502         buffer_put_int64(&msg, st->f_bfree);
 503         buffer_put_int64(&msg, st->f_bavail);
 504         buffer_put_int64(&msg, st->f_files);
 505         buffer_put_int64(&msg, st->f_ffree);
 506         buffer_put_int64(&msg, st->f_favail);
 507         buffer_put_int64(&msg, FSID_TO_ULONG(st->f_fsid));
 508         buffer_put_int64(&msg, flag);
 509         buffer_put_int64(&msg, st->f_namemax);
 510         send_msg(&msg);
 511         buffer_free(&msg);
 512 }
 513
 514 /* parse incoming */
 515
 516 static void
 517 process_init(void)
 518 {
 519         Buffer msg;
 520
 521         version = get_int();
 522         verbose("received client version %d", version);
 523         buffer_init(&msg);
 524         buffer_put_char(&msg, SSH2_FXP_VERSION);
 525         buffer_put_int(&msg, SSH2_FILEXFER_VERSION);
 526         /* POSIX rename extension */
 527         buffer_put_cstring(&msg, "posix-rename@openssh.com");
 528         buffer_put_cstring(&msg, "1"); /* version */
 529         /* statvfs extension */
 530         buffer_put_cstring(&msg, "statvfs@openssh.com");
 531         buffer_put_cstring(&msg, "2"); /* version */
 532         /* fstatvfs extension */
 533         buffer_put_cstring(&msg, "fstatvfs@openssh.com");
 534         buffer_put_cstring(&msg, "2"); /* version */
 535         send_msg(&msg);
 536         buffer_free(&msg);
 537 }
 538
 539 static void
 540 process_open(void)
 541 {
 542         u_int32_t id, pflags;
 543         Attrib *a;
 544         char *name;
 545         int handle, fd, flags, mode, status = SSH2_FX_FAILURE;
 546
 547         id = get_int();
 548         name = get_string(NULL);
 549         pflags = get_int();             /* portable flags */
 550         debug3("request %u: open flags %d", id, pflags);
 551         a = get_attrib();
 552         flags = flags_from_portable(pflags);
 553         mode = (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a->perm : 0666;
 554         logit("open \"%s\" flags %s mode 0%o",
 555             name, string_from_portable(pflags), mode);
 556         fd = open(name, flags, mode);
 557         if (fd < 0) {
 558                 status = errno_to_portable(errno);
 559         } else {
 560                 handle = handle_new(HANDLE_FILE, name, fd, NULL);
 561                 if (handle < 0) {
 562                         close(fd);
 563                 } else {
 564                         send_handle(id, handle);
 565                         status = SSH2_FX_OK;
 566                 }
 567         }
 568         if (status != SSH2_FX_OK)
 569                 send_status(id, status);
 570         xfree(name);
 571 }
 572
 573 static void
 574 process_close(void)
 575 {
 576         u_int32_t id;
 577         int handle, ret, status = SSH2_FX_FAILURE;
 578
 579         id = get_int();
 580         handle = get_handle();
 581         debug3("request %u: close handle %u", id, handle);
 582         handle_log_close(handle, NULL);
 583         ret = handle_close(handle);
 584         status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
 585         send_status(id, status);
 586 }
 587
 588 static void
 589 process_read(void)
 590 {
 591         char buf[64*1024];
 592         u_int32_t id, len;
 593         int handle, fd, ret, status = SSH2_FX_FAILURE;
 594         u_int64_t off;
 595
 596         id = get_int();
 597         handle = get_handle();
 598         off = get_int64();
 599         len = get_int();
 600
 601         debug("request %u: read \"%s\" (handle %d) off %llu len %d",
 602             id, handle_to_name(handle), handle, (unsigned long long)off, len);
 603         if (len > sizeof buf) {
 604                 len = sizeof buf;
 605                 debug2("read change len %d", len);
 606         }
 607         fd = handle_to_fd(handle);
 608         if (fd >= 0) {
 609                 if (lseek(fd, off, SEEK_SET) < 0) {
 610                         error("process_read: seek failed");
 611                         status = errno_to_portable(errno);
 612                 } else {
 613                         ret = read(fd, buf, len);
 614                         if (ret < 0) {
 615                                 status = errno_to_portable(errno);
 616                         } else if (ret == 0) {
 617                                 status = SSH2_FX_EOF;
 618                         } else {
 619                                 send_data(id, buf, ret);
 620                                 status = SSH2_FX_OK;
 621                                 handle_update_read(handle, ret);
 622                         }
 623                 }
 624         }
 625         if (status != SSH2_FX_OK)
 626                 send_status(id, status);
 627 }
 628
 629 static void
 630 process_write(void)
 631 {
 632         u_int32_t id;
 633         u_int64_t off;
 634         u_int len;
 635         int handle, fd, ret, status = SSH2_FX_FAILURE;
 636         char *data;
 637
 638         id = get_int();
 639         handle = get_handle();
 640         off = get_int64();
 641         data = get_string(&len);
 642
 643         debug("request %u: write \"%s\" (handle %d) off %llu len %d",
 644             id, handle_to_name(handle), handle, (unsigned long long)off, len);
 645         fd = handle_to_fd(handle);
 646         if (fd >= 0) {
 647                 if (lseek(fd, off, SEEK_SET) < 0) {
 648                         status = errno_to_portable(errno);
 649                         error("process_write: seek failed");
 650                 } else {
 651 /* XXX ATOMICIO ? */
 652                         ret = write(fd, data, len);
 653                         if (ret < 0) {
 654                                 error("process_write: write failed");
 655                                 status = errno_to_portable(errno);
 656                         } else if ((size_t)ret == len) {
 657                                 status = SSH2_FX_OK;
 658                                 handle_update_write(handle, ret);
 659                         } else {
 660                                 debug2("nothing at all written");
 661                         }
 662                 }
 663         }
 664         send_status(id, status);
 665         xfree(data);
 666 }
 667
 668 static void
 669 process_do_stat(int do_lstat)
 670 {
 671         Attrib a;
 672         struct stat st;
 673         u_int32_t id;
 674         char *name;
 675         int ret, status = SSH2_FX_FAILURE;
 676
 677         id = get_int();
 678         name = get_string(NULL);
 679         debug3("request %u: %sstat", id, do_lstat ? "l" : "");
 680         verbose("%sstat name \"%s\"", do_lstat ? "l" : "", name);
 681         ret = do_lstat ? lstat(name, &st) : stat(name, &st);
 682         if (ret < 0) {
 683                 status = errno_to_portable(errno);
 684         } else {
 685                 stat_to_attrib(&st, &a);
 686                 send_attrib(id, &a);
 687                 status = SSH2_FX_OK;
 688         }
 689         if (status != SSH2_FX_OK)
 690                 send_status(id, status);
 691         xfree(name);
 692 }
 693
 694 static void
 695 process_stat(void)
 696 {
 697         process_do_stat(0);
 698 }
 699
 700 static void
 701 process_lstat(void)
 702 {
 703         process_do_stat(1);
 704 }
 705
 706 static void
 707 process_fstat(void)
 708 {
 709         Attrib a;
 710         struct stat st;
 711         u_int32_t id;
 712         int fd, ret, handle, status = SSH2_FX_FAILURE;
 713
 714         id = get_int();
 715         handle = get_handle();
 716         debug("request %u: fstat \"%s\" (handle %u)",
 717             id, handle_to_name(handle), handle);
 718         fd = handle_to_fd(handle);
 719         if (fd >= 0) {
 720                 ret = fstat(fd, &st);
 721                 if (ret < 0) {
 722                         status = errno_to_portable(errno);
 723                 } else {
 724                         stat_to_attrib(&st, &a);
 725                         send_attrib(id, &a);
 726                         status = SSH2_FX_OK;
 727                 }
 728         }
 729         if (status != SSH2_FX_OK)
 730                 send_status(id, status);
 731 }
 732
 733 static struct timeval *
 734 attrib_to_tv(const Attrib *a)
 735 {
 736         static struct timeval tv[2];
 737
 738         tv[0].tv_sec = a->atime;
 739         tv[0].tv_usec = 0;
 740         tv[1].tv_sec = a->mtime;
 741         tv[1].tv_usec = 0;
 742         return tv;
 743 }
 744
 745 static void
 746 process_setstat(void)
 747 {
 748         Attrib *a;
 749         u_int32_t id;
 750         char *name;
 751         int status = SSH2_FX_OK, ret;
 752
 753         id = get_int();
 754         name = get_string(NULL);
 755         a = get_attrib();
 756         debug("request %u: setstat name \"%s\"", id, name);
 757         if (a->flags & SSH2_FILEXFER_ATTR_SIZE) {
 758                 logit("set \"%s\" size %llu",
 759                     name, (unsigned long long)a->size);
 760                 ret = truncate(name, a->size);
 761                 if (ret == -1)
 762                         status = errno_to_portable(errno);
 763         }
 764         if (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
 765                 logit("set \"%s\" mode %04o", name, a->perm);
 766                 ret = chmod(name, a->perm & 07777);
 767                 if (ret == -1)
 768                         status = errno_to_portable(errno);
 769         }
 770         if (a->flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
 771                 char buf[64];
 772                 time_t t = a->mtime;
 773
 774                 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
 775                     localtime(&t));
 776                 logit("set \"%s\" modtime %s", name, buf);
 777                 ret = utimes(name, attrib_to_tv(a));
 778                 if (ret == -1)
 779                         status = errno_to_portable(errno);
 780         }
 781         if (a->flags & SSH2_FILEXFER_ATTR_UIDGID) {
 782                 logit("set \"%s\" owner %lu group %lu", name,
 783                     (u_long)a->uid, (u_long)a->gid);
 784                 ret = chown(name, a->uid, a->gid);
 785                 if (ret == -1)
 786                         status = errno_to_portable(errno);
 787         }
 788         send_status(id, status);
 789         xfree(name);
 790 }
 791
 792 static void
 793 process_fsetstat(void)
 794 {
 795         Attrib *a;
 796         u_int32_t id;
 797         int handle, fd, ret;
 798         int status = SSH2_FX_OK;
 799
 800         id = get_int();
 801         handle = get_handle();
 802         a = get_attrib();
 803         debug("request %u: fsetstat handle %d", id, handle);
 804         fd = handle_to_fd(handle);
 805         if (fd < 0) {
 806                 status = SSH2_FX_FAILURE;
 807         } else {
 808                 char *name = handle_to_name(handle);
 809
 810                 if (a->flags & SSH2_FILEXFER_ATTR_SIZE) {
 811                         logit("set \"%s\" size %llu",
 812                             name, (unsigned long long)a->size);
 813                         ret = ftruncate(fd, a->size);
 814                         if (ret == -1)
 815                                 status = errno_to_portable(errno);
 816                 }
 817                 if (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
 818                         logit("set \"%s\" mode %04o", name, a->perm);
 819 #ifdef HAVE_FCHMOD
 820                         ret = fchmod(fd, a->perm & 07777);
 821 #else
 822                         ret = chmod(name, a->perm & 07777);
 823 #endif
 824                         if (ret == -1)
 825                                 status = errno_to_portable(errno);
 826                 }
 827                 if (a->flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
 828                         char buf[64];
 829                         time_t t = a->mtime;
 830
 831                         strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
 832                             localtime(&t));
 833                         logit("set \"%s\" modtime %s", name, buf);
 834 #ifdef HAVE_FUTIMES
 835                         ret = futimes(fd, attrib_to_tv(a));
 836 #else
 837                         ret = utimes(name, attrib_to_tv(a));
 838 #endif
 839                         if (ret == -1)
 840                                 status = errno_to_portable(errno);
 841                 }
 842                 if (a->flags & SSH2_FILEXFER_ATTR_UIDGID) {
 843                         logit("set \"%s\" owner %lu group %lu", name,
 844                             (u_long)a->uid, (u_long)a->gid);
 845 #ifdef HAVE_FCHOWN
 846                         ret = fchown(fd, a->uid, a->gid);
 847 #else
 848                         ret = chown(name, a->uid, a->gid);
 849 #endif
 850                         if (ret == -1)
 851                                 status = errno_to_portable(errno);
 852                 }
 853         }
 854         send_status(id, status);
 855 }
 856
 857 static void
 858 process_opendir(void)
 859 {
 860         DIR *dirp = NULL;
 861         char *path;
 862         int handle, status = SSH2_FX_FAILURE;
 863         u_int32_t id;
 864
 865         id = get_int();
 866         path = get_string(NULL);
 867         debug3("request %u: opendir", id);
 868         logit("opendir \"%s\"", path);
 869         dirp = opendir(path);
 870         if (dirp == NULL) {
 871                 status = errno_to_portable(errno);
 872         } else {
 873                 handle = handle_new(HANDLE_DIR, path, 0, dirp);
 874                 if (handle < 0) {
 875                         closedir(dirp);
 876                 } else {
 877                         send_handle(id, handle);
 878                         status = SSH2_FX_OK;
 879                 }
 880
 881         }
 882         if (status != SSH2_FX_OK)
 883                 send_status(id, status);
 884         xfree(path);
 885 }
 886
 887 static void
 888 process_readdir(void)
 889 {
 890         DIR *dirp;
 891         struct dirent *dp;
 892         char *path;
 893         int handle;
 894         u_int32_t id;
 895
 896         id = get_int();
 897         handle = get_handle();
 898         debug("request %u: readdir \"%s\" (handle %d)", id,
 899             handle_to_name(handle), handle);
 900         dirp = handle_to_dir(handle);
 901         path = handle_to_name(handle);
 902         if (dirp == NULL || path == NULL) {
 903                 send_status(id, SSH2_FX_FAILURE);
 904         } else {
 905                 struct stat st;
 906                 char pathname[MAXPATHLEN];
 907                 Stat *stats;
 908                 int nstats = 10, count = 0, i;
 909
 910                 stats = xcalloc(nstats, sizeof(Stat));
 911                 while ((dp = readdir(dirp)) != NULL) {
 912                         if (count >= nstats) {
 913                                 nstats *= 2;
 914                                 stats = xrealloc(stats, nstats, sizeof(Stat));
 915                         }
 916 /* XXX OVERFLOW ? */
 917                         snprintf(pathname, sizeof pathname, "%s%s%s", path,
 918                             strcmp(path, "/") ? "/" : "", dp->d_name);
 919                         if (lstat(pathname, &st) < 0)
 920                                 continue;
 921                         stat_to_attrib(&st, &(stats[count].attrib));
 922                         stats[count].name = xstrdup(dp->d_name);
 923                         stats[count].long_name = ls_file(dp->d_name, &st, 0);
 924                         count++;
 925                         /* send up to 100 entries in one message */
 926                         /* XXX check packet size instead */
 927                         if (count == 100)
 928                                 break;
 929                 }
 930                 if (count > 0) {
 931                         send_names(id, count, stats);
 932                         for (i = 0; i < count; i++) {
 933                                 xfree(stats[i].name);
 934                                 xfree(stats[i].long_name);
 935                         }
 936                 } else {
 937                         send_status(id, SSH2_FX_EOF);
 938                 }
 939                 xfree(stats);
 940         }
 941 }
 942
 943 static void
 944 process_remove(void)
 945 {
 946         char *name;
 947         u_int32_t id;
 948         int status = SSH2_FX_FAILURE;
 949         int ret;
 950
 951         id = get_int();
 952         name = get_string(NULL);
 953         debug3("request %u: remove", id);
 954         logit("remove name \"%s\"", name);
 955         ret = unlink(name);
 956         status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
 957         send_status(id, status);
 958         xfree(name);
 959 }
 960
 961 static void
 962 process_mkdir(void)
 963 {
 964         Attrib *a;
 965         u_int32_t id;
 966         char *name;
 967         int ret, mode, status = SSH2_FX_FAILURE;
 968
 969         id = get_int();
 970         name = get_string(NULL);
 971         a = get_attrib();
 972         mode = (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
 973             a->perm & 07777 : 0777;
 974         debug3("request %u: mkdir", id);
 975         logit("mkdir name \"%s\" mode 0%o", name, mode);
 976         ret = mkdir(name, mode);
 977         status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
 978         send_status(id, status);
 979         xfree(name);
 980 }
 981
 982 static void
 983 process_rmdir(void)
 984 {
 985         u_int32_t id;
 986         char *name;
 987         int ret, status;
 988
 989         id = get_int();
 990         name = get_string(NULL);
 991         debug3("request %u: rmdir", id);
 992         logit("rmdir name \"%s\"", name);
 993         ret = rmdir(name);
 994         status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
 995         send_status(id, status);
 996         xfree(name);
 997 }
 998
 999 static void
1000 process_realpath(void)
1001 {
1002         char resolvedname[MAXPATHLEN];
1003         u_int32_t id;
1004         char *path;
1005
1006         id = get_int();
1007         path = get_string(NULL);
1008         if (path[0] == '\0') {
1009                 xfree(path);
1010                 path = xstrdup(".");
1011         }
1012         debug3("request %u: realpath", id);
1013         verbose("realpath \"%s\"", path);
1014         if (realpath(path, resolvedname) == NULL) {
1015                 send_status(id, errno_to_portable(errno));
1016         } else {
1017                 Stat s;
1018                 attrib_clear(&s.attrib);
1019                 s.name = s.long_name = resolvedname;
1020                 send_names(id, 1, &s);
1021         }
1022         xfree(path);
1023 }
1024
1025 static void
1026 process_rename(void)
1027 {
1028         u_int32_t id;
1029         char *oldpath, *newpath;
1030         int status;
1031         struct stat sb;
1032
1033         id = get_int();
1034         oldpath = get_string(NULL);
1035         newpath = get_string(NULL);
1036         debug3("request %u: rename", id);
1037         logit("rename old \"%s\" new \"%s\"", oldpath, newpath);
1038         status = SSH2_FX_FAILURE;
1039         if (lstat(oldpath, &sb) == -1)
1040                 status = errno_to_portable(errno);
1041         else if (S_ISREG(sb.st_mode)) {
1042                 /* Race-free rename of regular files */
1043                 if (link(oldpath, newpath) == -1) {
1044                         if (errno == EOPNOTSUPP || errno == ENOSYS
1045 #ifdef EXDEV
1046                             || errno == EXDEV
1047 #endif
1048 #ifdef LINK_OPNOTSUPP_ERRNO
1049                             || errno == LINK_OPNOTSUPP_ERRNO
1050 #endif
1051                             ) {
1052                                 struct stat st;
1053
1054                                 /*
1055                                  * fs doesn't support links, so fall back to
1056                                  * stat+rename.  This is racy.
1057                                  */
1058                                 if (stat(newpath, &st) == -1) {
1059                                         if (rename(oldpath, newpath) == -1)
1060                                                 status =
1061                                                     errno_to_portable(errno);
1062                                         else
1063                                                 status = SSH2_FX_OK;
1064                                 }
1065                         } else {
1066                                 status = errno_to_portable(errno);
1067                         }
1068                 } else if (unlink(oldpath) == -1) {
1069                         status = errno_to_portable(errno);
1070                         /* clean spare link */
1071                         unlink(newpath);
1072                 } else
1073                         status = SSH2_FX_OK;
1074         } else if (stat(newpath, &sb) == -1) {
1075                 if (rename(oldpath, newpath) == -1)
1076                         status = errno_to_portable(errno);
1077                 else
1078                         status = SSH2_FX_OK;
1079         }
1080         send_status(id, status);
1081         xfree(oldpath);
1082         xfree(newpath);
1083 }
1084
1085 static void
1086 process_readlink(void)
1087 {
1088         u_int32_t id;
1089         int len;
1090         char buf[MAXPATHLEN];
1091         char *path;
1092
1093         id = get_int();
1094         path = get_string(NULL);
1095         debug3("request %u: readlink", id);
1096         verbose("readlink \"%s\"", path);
1097         if ((len = readlink(path, buf, sizeof(buf) - 1)) == -1)
1098                 send_status(id, errno_to_portable(errno));
1099         else {
1100                 Stat s;
1101
1102                 buf[len] = '\0';
1103                 attrib_clear(&s.attrib);
1104                 s.name = s.long_name = buf;
1105                 send_names(id, 1, &s);
1106         }
1107         xfree(path);
1108 }
1109
1110 static void
1111 process_symlink(void)
1112 {
1113         u_int32_t id;
1114         char *oldpath, *newpath;
1115         int ret, status;
1116
1117         id = get_int();
1118         oldpath = get_string(NULL);
1119         newpath = get_string(NULL);
1120         debug3("request %u: symlink", id);
1121         logit("symlink old \"%s\" new \"%s\"", oldpath, newpath);
1122         /* this will fail if 'newpath' exists */
1123         ret = symlink(oldpath, newpath);
1124         status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1125         send_status(id, status);
1126         xfree(oldpath);
1127         xfree(newpath);
1128 }
1129
1130 static void
1131 process_extended_posix_rename(u_int32_t id)
1132 {
1133         char *oldpath, *newpath;
1134
1135         oldpath = get_string(NULL);
1136         newpath = get_string(NULL);
1137         debug3("request %u: posix-rename", id);
1138         logit("posix-rename old \"%s\" new \"%s\"", oldpath, newpath);
1139         if (rename(oldpath, newpath) == -1)
1140                 send_status(id, errno_to_portable(errno));
1141         else
1142                 send_status(id, SSH2_FX_OK);
1143         xfree(oldpath);
1144         xfree(newpath);
1145 }
1146
1147 static void
1148 process_extended_statvfs(u_int32_t id)
1149 {
1150         char *path;
1151         struct statvfs st;
1152
1153         path = get_string(NULL);
1154         debug3("request %u: statfs", id);
1155         logit("statfs \"%s\"", path);
1156
1157         if (statvfs(path, &st) != 0)
1158                 send_status(id, errno_to_portable(errno));
1159         else
1160                 send_statvfs(id, &st);
1161         xfree(path);
1162 }
1163
1164 static void
1165 process_extended_fstatvfs(u_int32_t id)
1166 {
1167         int handle, fd;
1168         struct statvfs st;
1169
1170         handle = get_handle();
1171         debug("request %u: fstatvfs \"%s\" (handle %u)",
1172             id, handle_to_name(handle), handle);
1173         if ((fd = handle_to_fd(handle)) < 0) {
1174                 send_status(id, SSH2_FX_FAILURE);
1175                 return;
1176         }
1177         if (fstatvfs(fd, &st) != 0)
1178                 send_status(id, errno_to_portable(errno));
1179         else
1180                 send_statvfs(id, &st);
1181 }
1182
1183 static void
1184 process_extended(void)
1185 {
1186         u_int32_t id;
1187         char *request;
1188
1189         id = get_int();
1190         request = get_string(NULL);
1191         if (strcmp(request, "posix-rename@openssh.com") == 0)
1192                 process_extended_posix_rename(id);
1193         else if (strcmp(request, "statvfs@openssh.com") == 0)
1194                 process_extended_statvfs(id);
1195         else if (strcmp(request, "fstatvfs@openssh.com") == 0)
1196                 process_extended_fstatvfs(id);
1197         else
1198                 send_status(id, SSH2_FX_OP_UNSUPPORTED);        /* MUST */
1199         xfree(request);
1200 }
1201
1202 /* stolen from ssh-agent */
1203
1204 static void
1205 process(void)
1206 {
1207         u_int msg_len;
1208         u_int buf_len;
1209         u_int consumed;
1210         u_int type;
1211         u_char *cp;
1212
1213         buf_len = buffer_len(&iqueue);
1214         if (buf_len < 5)
1215                 return;         /* Incomplete message. */
1216         cp = buffer_ptr(&iqueue);
1217         msg_len = get_u32(cp);
1218         if (msg_len > SFTP_MAX_MSG_LENGTH) {
1219                 error("bad message from %s local user %s",
1220                     client_addr, pw->pw_name);
1221                 sftp_server_cleanup_exit(11);
1222         }
1223         if (buf_len < msg_len + 4)
1224                 return;
1225         buffer_consume(&iqueue, 4);
1226         buf_len -= 4;
1227         type = buffer_get_char(&iqueue);
1228         switch (type) {
1229         case SSH2_FXP_INIT:
1230                 process_init();
1231                 break;
1232         case SSH2_FXP_OPEN:
1233                 process_open();
1234                 break;
1235         case SSH2_FXP_CLOSE:
1236                 process_close();
1237                 break;
1238         case SSH2_FXP_READ:
1239                 process_read();
1240                 break;
1241         case SSH2_FXP_WRITE:
1242                 process_write();
1243                 break;
1244         case SSH2_FXP_LSTAT:
1245                 process_lstat();
1246                 break;
1247         case SSH2_FXP_FSTAT:
1248                 process_fstat();
1249                 break;
1250         case SSH2_FXP_SETSTAT:
1251                 process_setstat();
1252                 break;
1253         case SSH2_FXP_FSETSTAT:
1254                 process_fsetstat();
1255                 break;
1256         case SSH2_FXP_OPENDIR:
1257                 process_opendir();
1258                 break;
1259         case SSH2_FXP_READDIR:
1260                 process_readdir();
1261                 break;
1262         case SSH2_FXP_REMOVE:
1263                 process_remove();
1264                 break;
1265         case SSH2_FXP_MKDIR:
1266                 process_mkdir();
1267                 break;
1268         case SSH2_FXP_RMDIR:
1269                 process_rmdir();
1270                 break;
1271         case SSH2_FXP_REALPATH:
1272                 process_realpath();
1273                 break;
1274         case SSH2_FXP_STAT:
1275                 process_stat();
1276                 break;
1277         case SSH2_FXP_RENAME:
1278                 process_rename();
1279                 break;
1280         case SSH2_FXP_READLINK:
1281                 process_readlink();
1282                 break;
1283         case SSH2_FXP_SYMLINK:
1284                 process_symlink();
1285                 break;
1286         case SSH2_FXP_EXTENDED:
1287                 process_extended();
1288                 break;
1289         default:
1290                 error("Unknown message %d", type);
1291                 break;
1292         }
1293         /* discard the remaining bytes from the current packet */
1294         if (buf_len < buffer_len(&iqueue)) {
1295                 error("iqueue grew unexpectedly");
1296                 sftp_server_cleanup_exit(255);
1297         }
1298         consumed = buf_len - buffer_len(&iqueue);
1299         if (msg_len < consumed) {
1300                 error("msg_len %d < consumed %d", msg_len, consumed);
1301                 sftp_server_cleanup_exit(255);
1302         }
1303         if (msg_len > consumed)
1304                 buffer_consume(&iqueue, msg_len - consumed);
1305 }
1306
1307 /* Cleanup handler that logs active handles upon normal exit */
1308 void
1309 sftp_server_cleanup_exit(int i)
1310 {
1311         if (pw != NULL && client_addr != NULL) {
1312                 handle_log_exit();
1313                 logit("session closed for local user %s from [%s]",
1314                     pw->pw_name, client_addr);
1315         }
1316         _exit(i);
1317 }
1318
1319 static void
1320 sftp_server_usage(void)
1321 {
1322         extern char *__progname;
1323
1324         fprintf(stderr,
1325             "usage: %s [-eh] [-f log_facility] [-l log_level] [-u umask]\n",
1326             __progname);
1327         exit(1);
1328 }
1329
1330 int
1331 sftp_server_main(int argc, char **argv, struct passwd *user_pw)
1332 {
1333         fd_set *rset, *wset;
1334         int in, out, max, ch, skipargs = 0, log_stderr = 0;
1335         ssize_t len, olen, set_size;
1336         SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
1337         char *cp, buf[4*4096];
1338         const char *errmsg;
1339         mode_t mask;
1340
1341         extern char *optarg;
1342         extern char *__progname;
1343
1344         __progname = ssh_get_progname(argv[0]);
1345         log_init(__progname, log_level, log_facility, log_stderr);
1346
1347         while (!skipargs && (ch = getopt(argc, argv, "f:l:u:che")) != -1) {
1348                 switch (ch) {
1349                 case 'c':
1350                         /*
1351                          * Ignore all arguments if we are invoked as a
1352                          * shell using "sftp-server -c command"
1353                          */
1354                         skipargs = 1;
1355                         break;
1356                 case 'e':
1357                         log_stderr = 1;
1358                         break;
1359                 case 'l':
1360                         log_level = log_level_number(optarg);
1361                         if (log_level == SYSLOG_LEVEL_NOT_SET)
1362                                 error("Invalid log level \"%s\"", optarg);
1363                         break;
1364                 case 'f':
1365                         log_facility = log_facility_number(optarg);
1366                         if (log_facility == SYSLOG_FACILITY_NOT_SET)
1367                                 error("Invalid log facility \"%s\"", optarg);
1368                         break;
1369                 case 'u':
1370                         mask = (mode_t)strtonum(optarg, 0, 0777, &errmsg);
1371                         if (errmsg != NULL)
1372                                 fatal("Invalid umask \"%s\": %s",
1373                                     optarg, errmsg);
1374                         (void)umask(mask);
1375                         break;
1376                 case 'h':
1377                 default:
1378                         sftp_server_usage();
1379                 }
1380         }
1381
1382         log_init(__progname, log_level, log_facility, log_stderr);
1383
1384         if ((cp = getenv("SSH_CONNECTION")) != NULL) {
1385                 client_addr = xstrdup(cp);
1386                 if ((cp = strchr(client_addr, ' ')) == NULL) {
1387                         error("Malformed SSH_CONNECTION variable: \"%s\"",
1388                             getenv("SSH_CONNECTION"));
1389                         sftp_server_cleanup_exit(255);
1390                 }
1391                 *cp = '\0';
1392         } else
1393                 client_addr = xstrdup("UNKNOWN");
1394
1395         pw = pwcopy(user_pw);
1396
1397         logit("session opened for local user %s from [%s]",
1398             pw->pw_name, client_addr);
1399
1400         in = dup(STDIN_FILENO);
1401         out = dup(STDOUT_FILENO);
1402
1403 #ifdef HAVE_CYGWIN
1404         setmode(in, O_BINARY);
1405         setmode(out, O_BINARY);
1406 #endif
1407
1408         max = 0;
1409         if (in > max)
1410                 max = in;
1411         if (out > max)
1412                 max = out;
1413
1414         buffer_init(&iqueue);
1415         buffer_init(&oqueue);
1416
1417         set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
1418         rset = (fd_set *)xmalloc(set_size);
1419         wset = (fd_set *)xmalloc(set_size);
1420
1421         for (;;) {
1422                 memset(rset, 0, set_size);
1423                 memset(wset, 0, set_size);
1424
1425                 /*
1426                  * Ensure that we can read a full buffer and handle
1427                  * the worst-case length packet it can generate,
1428                  * otherwise apply backpressure by stopping reads.
1429                  */
1430                 if (buffer_check_alloc(&iqueue, sizeof(buf)) &&
1431                     buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH))
1432                         FD_SET(in, rset);
1433
1434                 olen = buffer_len(&oqueue);
1435                 if (olen > 0)
1436                         FD_SET(out, wset);
1437
1438                 if (select(max+1, rset, wset, NULL, NULL) < 0) {
1439                         if (errno == EINTR)
1440                                 continue;
1441                         error("select: %s", strerror(errno));
1442                         sftp_server_cleanup_exit(2);
1443                 }
1444
1445                 /* copy stdin to iqueue */
1446                 if (FD_ISSET(in, rset)) {
1447                         len = read(in, buf, sizeof buf);
1448                         if (len == 0) {
1449                                 debug("read eof");
1450                                 sftp_server_cleanup_exit(0);
1451                         } else if (len < 0) {
1452                                 error("read: %s", strerror(errno));
1453                                 sftp_server_cleanup_exit(1);
1454                         } else {
1455                                 buffer_append(&iqueue, buf, len);
1456                         }
1457                 }
1458                 /* send oqueue to stdout */
1459                 if (FD_ISSET(out, wset)) {
1460                         len = write(out, buffer_ptr(&oqueue), olen);
1461                         if (len < 0) {
1462                                 error("write: %s", strerror(errno));
1463                                 sftp_server_cleanup_exit(1);
1464                         } else {
1465                                 buffer_consume(&oqueue, len);
1466                         }
1467                 }
1468
1469                 /*
1470                  * Process requests from client if we can fit the results
1471                  * into the output buffer, otherwise stop processing input
1472                  * and let the output queue drain.
1473                  */
1474                 if (buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH))
1475                         process();
1476         }
1477 }