sys/kern/imgact_binmisc.c

   1 /*-
   2  * Copyright (c) 2013-15, Stacey D. Son
   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/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/ctype.h>
  32 #include <sys/sbuf.h>
  33 #include <sys/systm.h>
  34 #include <sys/sysproto.h>
  35 #include <sys/exec.h>
  36 #include <sys/imgact.h>
  37 #include <sys/imgact_binmisc.h>
  38 #include <sys/kernel.h>
  39 #include <sys/libkern.h>
  40 #include <sys/lock.h>
  41 #include <sys/malloc.h>
  42 #include <sys/mutex.h>
  43 #include <sys/sysctl.h>
  44 #include <sys/sx.h>
  45
  46 #include <machine/atomic.h>
  47
  48 /**
  49  * Miscellaneous binary interpreter image activator.
  50  *
  51  * If the given target executable's header matches 'xbe_magic' field in the
  52  * 'interpreter_list' then it will use the user-level interpreter specified in
  53  * the 'xbe_interpreter' field to execute the binary. The 'xbe_magic' field may
  54  * be adjusted to a given offset using the value in the 'xbe_moffset' field
  55  * and bits of the header may be masked using the 'xbe_mask' field.  The
  56  * 'interpreter_list' entries are managed using sysctl(3) as described in the
  57  * <sys/imgact_binmisc.h> file.
  58  */
  59
  60 /*
  61  * Node of the interpreter list.
  62  */
  63 typedef struct imgact_binmisc_entry {
  64         char                             *ibe_name;
  65         uint8_t                          *ibe_magic;
  66         uint32_t                          ibe_moffset;
  67         uint32_t                          ibe_msize;
  68         uint8_t                          *ibe_mask;
  69         uint8_t                          *ibe_interpreter;
  70         uint32_t                          ibe_interp_argcnt;
  71         uint32_t                          ibe_interp_length;
  72         uint32_t                          ibe_flags;
  73         SLIST_ENTRY(imgact_binmisc_entry) link;
  74 } imgact_binmisc_entry_t;
  75
  76 /*
  77  * sysctl() commands.
  78  */
  79 #define IBC_ADD         1       /* Add given entry. */
  80 #define IBC_REMOVE      2       /* Remove entry for a given name. */
  81 #define IBC_DISABLE     3       /* Disable entry for a given name. */
  82 #define IBC_ENABLE      4       /* Enable entry for a given name. */
  83 #define IBC_LOOKUP      5       /* Lookup and return entry for given name. */
  84 #define IBC_LIST        6       /* Get a snapshot of the interpretor list. */
  85
  86 /*
  87  * Interpreter string macros.
  88  *
  89  * They all start with '#' followed by a single letter:
  90  */
  91 #define ISM_POUND       '#'     /* "##" is the escape sequence for single #. */
  92 #define ISM_OLD_ARGV0   'a'     /* "#a" is replaced with the old argv0. */
  93
  94 MALLOC_DEFINE(M_BINMISC, KMOD_NAME, "misc binary image activator");
  95
  96 /* The interpreter list. */
  97 static SLIST_HEAD(, imgact_binmisc_entry) interpreter_list =
  98         SLIST_HEAD_INITIALIZER(interpreter_list);
  99
 100 static int interp_list_entry_count = 0;
 101
 102 static struct sx interp_list_sx;
 103
 104 int imgact_binmisc_exec(struct image_params *imgp);
 105
 106
 107 /*
 108  * Populate the entry with the information about the interpreter.
 109  */
 110 static void
 111 imgact_binmisc_populate_interp(char *str, imgact_binmisc_entry_t *ibe)
 112 {
 113         uint32_t len = 0, argc = 1;
 114         char t[IBE_INTERP_LEN_MAX];
 115         char *sp, *tp;
 116
 117         memset(t, 0, sizeof(t));
 118
 119         /*
 120          * Normalize interpreter string. Replace white space between args with
 121          * single space.
 122          */
 123         sp = str; tp = t;
 124         while (*sp != '\0') {
 125                 if (*sp == ' ' || *sp == '\t') {
 126                         if (++len > IBE_INTERP_LEN_MAX)
 127                                 break;
 128                         *tp++ = ' ';
 129                         argc++;
 130                         while (*sp == ' ' || *sp == '\t')
 131                                 sp++;
 132                         continue;
 133                 } else {
 134                         *tp++ = *sp++;
 135                         len++;
 136                 }
 137         }
 138         *tp = '\0';
 139         len++;
 140
 141         ibe->ibe_interpreter = malloc(len, M_BINMISC, M_WAITOK|M_ZERO);
 142
 143         /* Populate all the ibe fields for the interpreter. */
 144         memcpy(ibe->ibe_interpreter, t, len);
 145         ibe->ibe_interp_argcnt = argc;
 146         ibe->ibe_interp_length = len;
 147 }
 148
 149 /*
 150  * Allocate memory and populate a new entry for the interpreter table.
 151  */
 152 static imgact_binmisc_entry_t *
 153 imgact_binmisc_new_entry(ximgact_binmisc_entry_t *xbe)
 154 {
 155         imgact_binmisc_entry_t *ibe = NULL;
 156         size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX);
 157
 158         ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
 159
 160         ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
 161         strlcpy(ibe->ibe_name, xbe->xbe_name, namesz);
 162
 163         imgact_binmisc_populate_interp(xbe->xbe_interpreter, ibe);
 164
 165         ibe->ibe_magic = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
 166         memcpy(ibe->ibe_magic, xbe->xbe_magic, xbe->xbe_msize);
 167
 168         ibe->ibe_mask = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
 169         memcpy(ibe->ibe_mask, xbe->xbe_mask, xbe->xbe_msize);
 170
 171         ibe->ibe_moffset = xbe->xbe_moffset;
 172         ibe->ibe_msize = xbe->xbe_msize;
 173         ibe->ibe_flags = xbe->xbe_flags;
 174
 175         return (ibe);
 176 }
 177
 178 /*
 179  * Free the allocated memory for a given list item.
 180  */
 181 static void
 182 imgact_binmisc_destroy_entry(imgact_binmisc_entry_t *ibe)
 183 {
 184         if (!ibe)
 185                 return;
 186         if (ibe->ibe_magic)
 187                 free(ibe->ibe_magic, M_BINMISC);
 188         if (ibe->ibe_mask)
 189                 free(ibe->ibe_mask, M_BINMISC);
 190         if (ibe->ibe_interpreter)
 191                 free(ibe->ibe_interpreter, M_BINMISC);
 192         if (ibe->ibe_name)
 193                 free(ibe->ibe_name, M_BINMISC);
 194         if (ibe)
 195                 free(ibe, M_BINMISC);
 196 }
 197
 198 /*
 199  * Find the interpreter in the list by the given name.  Return NULL if not
 200  * found.
 201  */
 202 static imgact_binmisc_entry_t *
 203 imgact_binmisc_find_entry(char *name)
 204 {
 205         imgact_binmisc_entry_t *ibe;
 206
 207         sx_assert(&interp_list_sx, SA_LOCKED);
 208
 209         SLIST_FOREACH(ibe, &interpreter_list, link) {
 210                 if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
 211                         return (ibe);
 212         }
 213
 214         return (NULL);
 215 }
 216
 217 /*
 218  * Add the given interpreter if it doesn't already exist.  Return EEXIST
 219  * if the name already exist in the interpreter list.
 220  */
 221 static int
 222 imgact_binmisc_add_entry(ximgact_binmisc_entry_t *xbe)
 223 {
 224         imgact_binmisc_entry_t *ibe;
 225         char *p;
 226
 227         if (xbe->xbe_msize > IBE_MAGIC_MAX)
 228                 return (EINVAL);
 229
 230         for(p = xbe->xbe_name; *p != 0; p++)
 231                 if (!isascii((int)*p))
 232                         return (EINVAL);
 233
 234         for(p = xbe->xbe_interpreter; *p != 0; p++)
 235                 if (!isascii((int)*p))
 236                         return (EINVAL);
 237
 238         /* Make sure we don't have any invalid #'s. */
 239         p = xbe->xbe_interpreter;
 240         while (1) {
 241                 p = strchr(p, '#');
 242                 if (!p)
 243                         break;
 244
 245                 p++;
 246                 switch(*p) {
 247                 case ISM_POUND:
 248                         /* "##" */
 249                         p++;
 250                         break;
 251
 252                 case ISM_OLD_ARGV0:
 253                         /* "#a" */
 254                         p++;
 255                         break;
 256
 257                 case 0:
 258                 default:
 259                         /* Anything besides the above is invalid. */
 260                         return (EINVAL);
 261                 }
 262         }
 263
 264         sx_xlock(&interp_list_sx);
 265         if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
 266                 sx_xunlock(&interp_list_sx);
 267                 return (EEXIST);
 268         }
 269
 270         /* Preallocate a new entry. */
 271         ibe = imgact_binmisc_new_entry(xbe);
 272         if (!ibe)
 273                 return (ENOMEM);
 274
 275         SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
 276         interp_list_entry_count++;
 277         sx_xunlock(&interp_list_sx);
 278
 279         return (0);
 280 }
 281
 282 /*
 283  * Remove the interpreter in the list with the given name. Return ENOENT
 284  * if not found.
 285  */
 286 static int
 287 imgact_binmisc_remove_entry(char *name)
 288 {
 289         imgact_binmisc_entry_t *ibe;
 290
 291         sx_xlock(&interp_list_sx);
 292         if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
 293                 sx_xunlock(&interp_list_sx);
 294                 return (ENOENT);
 295         }
 296         SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
 297         interp_list_entry_count--;
 298         sx_xunlock(&interp_list_sx);
 299
 300         imgact_binmisc_destroy_entry(ibe);
 301
 302         return (0);
 303 }
 304
 305 /*
 306  * Disable the interpreter in the list with the given name. Return ENOENT
 307  * if not found.
 308  */
 309 static int
 310 imgact_binmisc_disable_entry(char *name)
 311 {
 312         imgact_binmisc_entry_t *ibe;
 313
 314         sx_slock(&interp_list_sx);
 315         if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
 316                 sx_sunlock(&interp_list_sx);
 317                 return (ENOENT);
 318         }
 319
 320         atomic_clear_32(&ibe->ibe_flags, IBF_ENABLED);
 321         sx_sunlock(&interp_list_sx);
 322
 323         return (0);
 324 }
 325
 326 /*
 327  * Enable the interpreter in the list with the given name. Return ENOENT
 328  * if not found.
 329  */
 330 static int
 331 imgact_binmisc_enable_entry(char *name)
 332 {
 333         imgact_binmisc_entry_t *ibe;
 334
 335         sx_slock(&interp_list_sx);
 336         if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
 337                 sx_sunlock(&interp_list_sx);
 338                 return (ENOENT);
 339         }
 340
 341         atomic_set_32(&ibe->ibe_flags, IBF_ENABLED);
 342         sx_sunlock(&interp_list_sx);
 343
 344         return (0);
 345 }
 346
 347 static int
 348 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
 349     imgact_binmisc_entry_t *ibe)
 350 {
 351         uint32_t i;
 352
 353         sx_assert(&interp_list_sx, SA_LOCKED);
 354
 355         memset(xbe, 0, sizeof(*xbe));
 356         strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
 357
 358         /* Copy interpreter string.  Replace NULL breaks with space. */
 359         memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
 360             ibe->ibe_interp_length);
 361         for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
 362                 if (xbe->xbe_interpreter[i] == '\0')
 363                         xbe->xbe_interpreter[i] = ' ';
 364
 365         memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
 366         memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
 367         xbe->xbe_version = IBE_VERSION;
 368         xbe->xbe_flags = ibe->ibe_flags;
 369         xbe->xbe_moffset = ibe->ibe_moffset;
 370         xbe->xbe_msize = ibe->ibe_msize;
 371
 372         return (0);
 373 }
 374
 375 /*
 376  * Retrieve the interpreter with the give name and populate the
 377  * ximgact_binmisc_entry structure.  Return ENOENT if not found.
 378  */
 379 static int
 380 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
 381 {
 382         imgact_binmisc_entry_t *ibe;
 383         int error = 0;
 384
 385         sx_slock(&interp_list_sx);
 386         if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
 387                 sx_sunlock(&interp_list_sx);
 388                 return (ENOENT);
 389         }
 390
 391         error = imgact_binmisc_populate_xbe(xbe, ibe);
 392         sx_sunlock(&interp_list_sx);
 393
 394         return (error);
 395 }
 396
 397 /*
 398  * Get a snapshot of all the interpreter entries in the list.
 399  */
 400 static int
 401 imgact_binmisc_get_all_entries(struct sysctl_req *req)
 402 {
 403         ximgact_binmisc_entry_t *xbe, *xbep;
 404         imgact_binmisc_entry_t *ibe;
 405         int error = 0, count;
 406
 407         sx_slock(&interp_list_sx);
 408         count = interp_list_entry_count;
 409         xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_ZERO);
 410         if (!xbe) {
 411                 sx_sunlock(&interp_list_sx);
 412                 return (ENOMEM);
 413         }
 414
 415         xbep = xbe;
 416         SLIST_FOREACH(ibe, &interpreter_list, link) {
 417                 error = imgact_binmisc_populate_xbe(xbep++, ibe);
 418                 if (error)
 419                         break;
 420         }
 421         sx_sunlock(&interp_list_sx);
 422
 423         if (!error)
 424                 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
 425
 426         free(xbe, M_BINMISC);
 427         return (error);
 428 }
 429
 430 /*
 431  * sysctl() handler for munipulating interpretor table.
 432  * Not MP safe (locked by sysctl).
 433  */
 434 static int
 435 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
 436 {
 437         ximgact_binmisc_entry_t xbe;
 438         int error = 0;
 439
 440         switch(arg2) {
 441         case IBC_ADD:
 442                 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
 443                 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
 444                 if (error)
 445                         return (error);
 446                 if (IBE_VERSION != xbe.xbe_version)
 447                         return (EINVAL);
 448                 if (interp_list_entry_count == IBE_MAX_ENTRIES)
 449                         return (ENOSPC);
 450                 error = imgact_binmisc_add_entry(&xbe);
 451                 break;
 452
 453         case IBC_REMOVE:
 454                 /* Remove an entry. */
 455                 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
 456                 if (error)
 457                         return (error);
 458                 if (IBE_VERSION != xbe.xbe_version)
 459                         return (EINVAL);
 460                 error = imgact_binmisc_remove_entry(xbe.xbe_name);
 461                 break;
 462
 463         case IBC_DISABLE:
 464                 /* Disable an entry. */
 465                 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
 466                 if (error)
 467                         return (error);
 468                 if (IBE_VERSION != xbe.xbe_version)
 469                         return (EINVAL);
 470                 error = imgact_binmisc_disable_entry(xbe.xbe_name);
 471                 break;
 472
 473         case IBC_ENABLE:
 474                 /* Enable an entry. */
 475                 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
 476                 if (error)
 477                         return (error);
 478                 if (IBE_VERSION != xbe.xbe_version)
 479                         return (EINVAL);
 480                 error = imgact_binmisc_enable_entry(xbe.xbe_name);
 481                 break;
 482
 483         case IBC_LOOKUP:
 484                 /* Lookup an entry. */
 485                 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
 486                 if (error)
 487                         return (error);
 488                 if (IBE_VERSION != xbe.xbe_version)
 489                         return (EINVAL);
 490                 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
 491                 if (!error)
 492                         error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
 493                 break;
 494
 495         case IBC_LIST:
 496                 /* Return a snapshot of the interpretor list. */
 497
 498                 if (!req->oldptr) {
 499                         /* No pointer then just return the list size. */
 500                         error = SYSCTL_OUT(req, 0, interp_list_entry_count *
 501                             sizeof(ximgact_binmisc_entry_t));
 502                         return (error);
 503                 } else
 504                         if (!req->oldlen)
 505                                 return (EINVAL);
 506
 507                 error = imgact_binmisc_get_all_entries(req);
 508                 break;
 509
 510         default:
 511                 return (EINVAL);
 512         }
 513
 514         return (error);
 515 }
 516
 517 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW, 0,
 518     "Image activator for miscellaneous binaries");
 519
 520 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
 521     CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
 522     sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
 523     "Add an activator entry");
 524
 525 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
 526     CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
 527     sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
 528     "Remove an activator entry");
 529
 530 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
 531     CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
 532     sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
 533     "Disable an activator entry");
 534
 535 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
 536     CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
 537     sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
 538     "Enable an activator entry");
 539
 540 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
 541     CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
 542     sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
 543     "Lookup an activator entry");
 544
 545 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
 546     CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
 547     sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
 548     "Get snapshot of all the activator entries");
 549
 550 static imgact_binmisc_entry_t *
 551 imgact_binmisc_find_interpreter(const char *image_header)
 552 {
 553         imgact_binmisc_entry_t *ibe;
 554         const char *p;
 555         int i;
 556         size_t sz;
 557
 558         sx_assert(&interp_list_sx, SA_LOCKED);
 559
 560         SLIST_FOREACH(ibe, &interpreter_list, link) {
 561                 if (!(IBF_ENABLED & ibe->ibe_flags))
 562                         continue;
 563
 564                 p = image_header + ibe->ibe_moffset;
 565                 sz = ibe->ibe_msize;
 566                 if (IBF_USE_MASK & ibe->ibe_flags) {
 567                         /* Compare using mask. */
 568                         for (i = 0; i < sz; i++)
 569                                 if ((*p++ ^ ibe->ibe_magic[i]) &
 570                                     ibe->ibe_mask[i])
 571                                         break;
 572                 } else {
 573                         for (i = 0; i < sz; i++)
 574                                 if (*p++ ^ ibe->ibe_magic[i])
 575                                         break;
 576                 }
 577                 if (i == ibe->ibe_msize)
 578                         return (ibe);
 579         }
 580         return (NULL);
 581 }
 582
 583 int
 584 imgact_binmisc_exec(struct image_params *imgp)
 585 {
 586         const char *image_header = imgp->image_header;
 587         const char *fname = NULL;
 588         int error = 0;
 589         size_t offset, l;
 590         imgact_binmisc_entry_t *ibe;
 591         struct sbuf *sname;
 592         char *s, *d;
 593
 594         /* Do we have an interpreter for the given image header? */
 595         sx_slock(&interp_list_sx);
 596         if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
 597                 sx_sunlock(&interp_list_sx);
 598                 return (-1);
 599         }
 600
 601         /* No interpreter nesting allowed. */
 602         if (imgp->interpreted & IMGACT_BINMISC) {
 603                 sx_sunlock(&interp_list_sx);
 604                 return (ENOEXEC);
 605         }
 606
 607         imgp->interpreted |= IMGACT_BINMISC;
 608
 609         if (imgp->args->fname != NULL) {
 610                 fname = imgp->args->fname;
 611                 sname = NULL;
 612         } else {
 613                 /* Use the fdescfs(5) path for fexecve(2). */
 614                 sname = sbuf_new_auto();
 615                 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
 616                 sbuf_finish(sname);
 617                 fname = sbuf_data(sname);
 618         }
 619
 620
 621         /*
 622          * We need to "push" the interpreter in the arg[] list.  To do this,
 623          * we first shift all the other values in the `begin_argv' area to
 624          * provide the exact amount of room for the values added.  Set up
 625          * `offset' as the number of bytes to be added to the `begin_argv'
 626          * area.
 627          */
 628         offset = ibe->ibe_interp_length;
 629
 630         /* Adjust the offset for #'s. */
 631         s = ibe->ibe_interpreter;
 632         while (1) {
 633                 s = strchr(s, '#');
 634                 if (!s)
 635                         break;
 636
 637                 s++;
 638                 switch(*s) {
 639                 case ISM_POUND:
 640                         /* "##" -> "#": reduce offset by one. */
 641                         offset--;
 642                         break;
 643
 644                 case ISM_OLD_ARGV0:
 645                         /* "#a" -> (old argv0): increase offset to fit fname */
 646                         offset += strlen(fname) - 2;
 647                         break;
 648
 649                 default:
 650                         /* Hmm... This shouldn't happen. */
 651                         sx_sunlock(&interp_list_sx);
 652                         printf("%s: Unknown macro #%c sequence in "
 653                             "interpreter string\n", KMOD_NAME, *(s + 1));
 654                         error = EINVAL;
 655                         goto done;
 656                 }
 657                 s++;
 658         }
 659
 660         /* Check to make sure we won't overrun the stringspace. */
 661         if (offset > imgp->args->stringspace) {
 662                 sx_sunlock(&interp_list_sx);
 663                 error = E2BIG;
 664                 goto done;
 665         }
 666
 667         /* Make room for the interpreter */
 668         bcopy(imgp->args->begin_argv, imgp->args->begin_argv + offset,
 669             imgp->args->endp - imgp->args->begin_argv);
 670
 671         /* Adjust everything by the offset. */
 672         imgp->args->begin_envv += offset;
 673         imgp->args->endp += offset;
 674         imgp->args->stringspace -= offset;
 675
 676         /* Add the new argument(s) in the count. */
 677         imgp->args->argc += ibe->ibe_interp_argcnt;
 678
 679         /*
 680          * The original arg[] list has been shifted appropriately.  Copy in
 681          * the interpreter path.
 682          */
 683         s = ibe->ibe_interpreter;
 684         d = imgp->args->begin_argv;
 685         while(*s != '\0') {
 686                 switch (*s) {
 687                 case '#':
 688                         /* Handle "#" in interpreter string. */
 689                         s++;
 690                         switch(*s) {
 691                         case ISM_POUND:
 692                                 /* "##": Replace with a single '#' */
 693                                 *d++ = '#';
 694                                 break;
 695
 696                         case ISM_OLD_ARGV0:
 697                                 /* "#a": Replace with old arg0 (fname). */
 698                                 if ((l = strlen(fname)) != 0) {
 699                                         memcpy(d, fname, l);
 700                                         d += l;
 701                                 }
 702                                 break;
 703
 704                         default:
 705                                 /* Shouldn't happen but skip it if it does. */
 706                                 break;
 707                         }
 708                         break;
 709
 710                 case ' ':
 711                         /* Replace space with NUL to seperate arguments. */
 712                         *d++ = '\0';
 713                         break;
 714
 715                 default:
 716                         *d++ = *s;
 717                         break;
 718                 }
 719                 s++;
 720         }
 721         *d = '\0';
 722         sx_sunlock(&interp_list_sx);
 723
 724         if (!error)
 725                 imgp->interpreter_name = imgp->args->begin_argv;
 726
 727
 728 done:
 729         if (sname)
 730                 sbuf_delete(sname);
 731         return (error);
 732 }
 733
 734 static void
 735 imgact_binmisc_init(void *arg)
 736 {
 737
 738         sx_init(&interp_list_sx, KMOD_NAME);
 739 }
 740
 741 static void
 742 imgact_binmisc_fini(void *arg)
 743 {
 744         imgact_binmisc_entry_t *ibe, *ibe_tmp;
 745
 746         /* Free all the interpreters. */
 747         sx_xlock(&interp_list_sx);
 748         SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
 749                 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
 750                     link);
 751                 imgact_binmisc_destroy_entry(ibe);
 752         }
 753         sx_xunlock(&interp_list_sx);
 754
 755         sx_destroy(&interp_list_sx);
 756 }
 757
 758 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init, 0);
 759 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini, 0);
 760
 761 /*
 762  * Tell kern_execve.c about it, with a little help from the linker.
 763  */
 764 static struct execsw imgact_binmisc_execsw = { imgact_binmisc_exec, KMOD_NAME };
 765 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);