Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/binfmt_aout.c
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1 /* 2 * linux/fs/binfmt_aout.c 3 * 4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds 5 */ 6 7 #include <linux/module.h> 8 9 #include <linux/sched.h> 10 #include <linux/kernel.h> 11 #include <linux/mm.h> 12 #include <linux/mman.h> 13 #include <linux/a.out.h> 14 #include <linux/errno.h> 15 #include <linux/signal.h> 16 #include <linux/string.h> 17 #include <linux/fs.h> 18 #include <linux/file.h> 19 #include <linux/stat.h> 20 #include <linux/fcntl.h> 21 #include <linux/ptrace.h> 22 #include <linux/user.h> 23 #include <linux/slab.h> 24 #include <linux/binfmts.h> 25 #include <linux/personality.h> 26 #include <linux/init.h> 27 28 #include <asm/system.h> 29 #include <asm/uaccess.h> 30 #include <asm/pgalloc.h> 31 32 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); 33 static int load_aout_library(struct file*); 34 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file); 35 36 extern void dump_thread(struct pt_regs *, struct user *); 37 38 static struct linux_binfmt aout_format = { 39 NULL, THIS_MODULE, load_aout_binary, load_aout_library, aout_core_dump, PAGE_SIZE 40 }; 41 42 static void set_brk(unsigned long start, unsigned long end) 43 { 44 start = PAGE_ALIGN(start); 45 end = PAGE_ALIGN(end); 46 if (end <= start) 47 return; 48 do_brk(start, end - start); 49 } 50 51 /* 52 * These are the only things you should do on a core-file: use only these 53 * macros to write out all the necessary info. 54 */ 55 56 static int dump_write(struct file *file, const void *addr, int nr) 57 { 58 return file->f_op->write(file, addr, nr, &file->f_pos) == nr; 59 } 60 61 #define DUMP_WRITE(addr, nr) \ 62 if (!dump_write(file, (void *)(addr), (nr))) \ 63 goto end_coredump; 64 65 #define DUMP_SEEK(offset) \ 66 if (file->f_op->llseek) { \ 67 if (file->f_op->llseek(file,(offset),0) != (offset)) \ 68 goto end_coredump; \ 69 } else file->f_pos = (offset) 70 71 /* 72 * Routine writes a core dump image in the current directory. 73 * Currently only a stub-function. 74 * 75 * Note that setuid/setgid files won't make a core-dump if the uid/gid 76 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable" 77 * field, which also makes sure the core-dumps won't be recursive if the 78 * dumping of the process results in another error.. 79 */ 80 81 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file) 82 { 83 mm_segment_t fs; 84 int has_dumped = 0; 85 unsigned long dump_start, dump_size; 86 struct user dump; 87 #if defined(__alpha__) 88 # define START_DATA(u) (u.start_data) 89 #elif defined(__arm__) 90 # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code) 91 #elif defined(__sparc__) 92 # define START_DATA(u) (u.u_tsize) 93 #elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__) 94 # define START_DATA(u) (u.u_tsize << PAGE_SHIFT) 95 #endif 96 #ifdef __sparc__ 97 # define START_STACK(u) ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1)) 98 #else 99 # define START_STACK(u) (u.start_stack) 100 #endif 101 102 fs = get_fs(); 103 set_fs(KERNEL_DS); 104 has_dumped = 1; 105 current->flags |= PF_DUMPCORE; 106 strncpy(dump.u_comm, current->comm, sizeof(current->comm)); 107 #ifndef __sparc__ 108 dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump))); 109 #endif 110 dump.signal = signr; 111 dump_thread(regs, &dump); 112 113 /* If the size of the dump file exceeds the rlimit, then see what would happen 114 if we wrote the stack, but not the data area. */ 115 #ifdef __sparc__ 116 if ((dump.u_dsize+dump.u_ssize) > 117 current->rlim[RLIMIT_CORE].rlim_cur) 118 dump.u_dsize = 0; 119 #else 120 if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE > 121 current->rlim[RLIMIT_CORE].rlim_cur) 122 dump.u_dsize = 0; 123 #endif 124 125 /* Make sure we have enough room to write the stack and data areas. */ 126 #ifdef __sparc__ 127 if ((dump.u_ssize) > 128 current->rlim[RLIMIT_CORE].rlim_cur) 129 dump.u_ssize = 0; 130 #else 131 if ((dump.u_ssize+1) * PAGE_SIZE > 132 current->rlim[RLIMIT_CORE].rlim_cur) 133 dump.u_ssize = 0; 134 #endif 135 136 /* make sure we actually have a data and stack area to dump */ 137 set_fs(USER_DS); 138 #ifdef __sparc__ 139 if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize)) 140 dump.u_dsize = 0; 141 if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize)) 142 dump.u_ssize = 0; 143 #else 144 if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) 145 dump.u_dsize = 0; 146 if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) 147 dump.u_ssize = 0; 148 #endif 149 150 set_fs(KERNEL_DS); 151 /* struct user */ 152 DUMP_WRITE(&dump,sizeof(dump)); 153 /* Now dump all of the user data. Include malloced stuff as well */ 154 #ifndef __sparc__ 155 DUMP_SEEK(PAGE_SIZE); 156 #endif 157 /* now we start writing out the user space info */ 158 set_fs(USER_DS); 159 /* Dump the data area */ 160 if (dump.u_dsize != 0) { 161 dump_start = START_DATA(dump); 162 #ifdef __sparc__ 163 dump_size = dump.u_dsize; 164 #else 165 dump_size = dump.u_dsize << PAGE_SHIFT; 166 #endif 167 DUMP_WRITE(dump_start,dump_size); 168 } 169 /* Now prepare to dump the stack area */ 170 if (dump.u_ssize != 0) { 171 dump_start = START_STACK(dump); 172 #ifdef __sparc__ 173 dump_size = dump.u_ssize; 174 #else 175 dump_size = dump.u_ssize << PAGE_SHIFT; 176 #endif 177 DUMP_WRITE(dump_start,dump_size); 178 } 179 /* Finally dump the task struct. Not be used by gdb, but could be useful */ 180 set_fs(KERNEL_DS); 181 DUMP_WRITE(current,sizeof(*current)); 182 end_coredump: 183 set_fs(fs); 184 return has_dumped; 185 } 186 187 /* 188 * create_aout_tables() parses the env- and arg-strings in new user 189 * memory and creates the pointer tables from them, and puts their 190 * addresses on the "stack", returning the new stack pointer value. 191 */ 192 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm) 193 { 194 char **argv, **envp; 195 unsigned long * sp; 196 int argc = bprm->argc; 197 int envc = bprm->envc; 198 199 sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p); 200 #ifdef __sparc__ 201 /* This imposes the proper stack alignment for a new process. */ 202 sp = (unsigned long *) (((unsigned long) sp) & ~7); 203 if ((envc+argc+3)&1) --sp; 204 #endif 205 #ifdef __alpha__ 206 /* whee.. test-programs are so much fun. */ 207 put_user(0, --sp); 208 put_user(0, --sp); 209 if (bprm->loader) { 210 put_user(0, --sp); 211 put_user(0x3eb, --sp); 212 put_user(bprm->loader, --sp); 213 put_user(0x3ea, --sp); 214 } 215 put_user(bprm->exec, --sp); 216 put_user(0x3e9, --sp); 217 #endif 218 sp -= envc+1; 219 envp = (char **) sp; 220 sp -= argc+1; 221 argv = (char **) sp; 222 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__) 223 put_user((unsigned long) envp,--sp); 224 put_user((unsigned long) argv,--sp); 225 #endif 226 put_user(argc,--sp); 227 current->mm->arg_start = (unsigned long) p; 228 while (argc-->0) { 229 char c; 230 put_user(p,argv++); 231 do { 232 get_user(c,p++); 233 } while (c); 234 } 235 put_user(NULL,argv); 236 current->mm->arg_end = current->mm->env_start = (unsigned long) p; 237 while (envc-->0) { 238 char c; 239 put_user(p,envp++); 240 do { 241 get_user(c,p++); 242 } while (c); 243 } 244 put_user(NULL,envp); 245 current->mm->env_end = (unsigned long) p; 246 return sp; 247 } 248 249 /* 250 * These are the functions used to load a.out style executables and shared 251 * libraries. There is no binary dependent code anywhere else. 252 */ 253 254 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs) 255 { 256 struct exec ex; 257 unsigned long error; 258 unsigned long fd_offset; 259 unsigned long rlim; 260 int retval; 261 262 ex = *((struct exec *) bprm->buf); /* exec-header */ 263 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && 264 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || 265 N_TRSIZE(ex) || N_DRSIZE(ex) || 266 bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { 267 return -ENOEXEC; 268 } 269 270 fd_offset = N_TXTOFF(ex); 271 272 /* Check initial limits. This avoids letting people circumvent 273 * size limits imposed on them by creating programs with large 274 * arrays in the data or bss. 275 */ 276 rlim = current->rlim[RLIMIT_DATA].rlim_cur; 277 if (rlim >= RLIM_INFINITY) 278 rlim = ~0; 279 if (ex.a_data + ex.a_bss > rlim) 280 return -ENOMEM; 281 282 /* Flush all traces of the currently running executable */ 283 retval = flush_old_exec(bprm); 284 if (retval) 285 return retval; 286 287 /* OK, This is the point of no return */ 288 #if defined(__alpha__) 289 SET_AOUT_PERSONALITY(bprm, ex); 290 #elif defined(__sparc__) 291 set_personality(PER_SUNOS); 292 #if !defined(__sparc_v9__) 293 memcpy(¤t->thread.core_exec, &ex, sizeof(struct exec)); 294 #endif 295 #else 296 set_personality(PER_LINUX); 297 #endif 298 299 current->mm->end_code = ex.a_text + 300 (current->mm->start_code = N_TXTADDR(ex)); 301 current->mm->end_data = ex.a_data + 302 (current->mm->start_data = N_DATADDR(ex)); 303 current->mm->brk = ex.a_bss + 304 (current->mm->start_brk = N_BSSADDR(ex)); 305 306 current->mm->rss = 0; 307 current->mm->mmap = NULL; 308 compute_creds(bprm); 309 current->flags &= ~PF_FORKNOEXEC; 310 #ifdef __sparc__ 311 if (N_MAGIC(ex) == NMAGIC) { 312 loff_t pos = fd_offset; 313 /* Fuck me plenty... */ 314 /* <AOL></AOL> */ 315 error = do_brk(N_TXTADDR(ex), ex.a_text); 316 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex), 317 ex.a_text, &pos); 318 error = do_brk(N_DATADDR(ex), ex.a_data); 319 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex), 320 ex.a_data, &pos); 321 goto beyond_if; 322 } 323 #endif 324 325 if (N_MAGIC(ex) == OMAGIC) { 326 unsigned long text_addr, map_size; 327 loff_t pos; 328 329 text_addr = N_TXTADDR(ex); 330 331 #if defined(__alpha__) || defined(__sparc__) 332 pos = fd_offset; 333 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; 334 #else 335 pos = 32; 336 map_size = ex.a_text+ex.a_data; 337 #endif 338 339 error = do_brk(text_addr & PAGE_MASK, map_size); 340 if (error != (text_addr & PAGE_MASK)) { 341 send_sig(SIGKILL, current, 0); 342 return error; 343 } 344 345 error = bprm->file->f_op->read(bprm->file, (char *)text_addr, 346 ex.a_text+ex.a_data, &pos); 347 if ((signed long)error < 0) { 348 send_sig(SIGKILL, current, 0); 349 return error; 350 } 351 352 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data); 353 } else { 354 static unsigned long error_time, error_time2; 355 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && 356 (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ) 357 { 358 printk(KERN_NOTICE "executable not page aligned\n"); 359 error_time2 = jiffies; 360 } 361 362 if ((fd_offset & ~PAGE_MASK) != 0 && 363 (jiffies-error_time) > 5*HZ) 364 { 365 printk(KERN_WARNING 366 "fd_offset is not page aligned. Please convert program: %s\n", 367 bprm->file->f_dentry->d_name.name); 368 error_time = jiffies; 369 } 370 371 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { 372 loff_t pos = fd_offset; 373 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); 374 bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex), 375 ex.a_text+ex.a_data, &pos); 376 flush_icache_range((unsigned long) N_TXTADDR(ex), 377 (unsigned long) N_TXTADDR(ex) + 378 ex.a_text+ex.a_data); 379 goto beyond_if; 380 } 381 382 down_write(¤t->mm->mmap_sem); 383 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, 384 PROT_READ | PROT_EXEC, 385 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, 386 fd_offset); 387 up_write(¤t->mm->mmap_sem); 388 389 if (error != N_TXTADDR(ex)) { 390 send_sig(SIGKILL, current, 0); 391 return error; 392 } 393 394 down_write(¤t->mm->mmap_sem); 395 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data, 396 PROT_READ | PROT_WRITE | PROT_EXEC, 397 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, 398 fd_offset + ex.a_text); 399 up_write(¤t->mm->mmap_sem); 400 if (error != N_DATADDR(ex)) { 401 send_sig(SIGKILL, current, 0); 402 return error; 403 } 404 } 405 beyond_if: 406 set_binfmt(&aout_format); 407 408 set_brk(current->mm->start_brk, current->mm->brk); 409 410 retval = setup_arg_pages(bprm); 411 if (retval < 0) { 412 /* Someone check-me: is this error path enough? */ 413 send_sig(SIGKILL, current, 0); 414 return retval; 415 } 416 417 current->mm->start_stack = 418 (unsigned long) create_aout_tables((char *) bprm->p, bprm); 419 #ifdef __alpha__ 420 regs->gp = ex.a_gpvalue; 421 #endif 422 start_thread(regs, ex.a_entry, current->mm->start_stack); 423 if (current->ptrace & PT_PTRACED) 424 send_sig(SIGTRAP, current, 0); 425 return 0; 426 } 427 428 static int load_aout_library(struct file *file) 429 { 430 struct inode * inode; 431 unsigned long bss, start_addr, len; 432 unsigned long error; 433 int retval; 434 struct exec ex; 435 436 inode = file->f_dentry->d_inode; 437 438 retval = -ENOEXEC; 439 error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); 440 if (error != sizeof(ex)) 441 goto out; 442 443 /* We come in here for the regular a.out style of shared libraries */ 444 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || 445 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || 446 inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { 447 goto out; 448 } 449 450 if (N_FLAGS(ex)) 451 goto out; 452 453 /* For QMAGIC, the starting address is 0x20 into the page. We mask 454 this off to get the starting address for the page */ 455 456 start_addr = ex.a_entry & 0xfffff000; 457 458 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { 459 static unsigned long error_time; 460 loff_t pos = N_TXTOFF(ex); 461 462 if ((jiffies-error_time) > 5*HZ) 463 { 464 printk(KERN_WARNING 465 "N_TXTOFF is not page aligned. Please convert library: %s\n", 466 file->f_dentry->d_name.name); 467 error_time = jiffies; 468 } 469 470 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); 471 472 file->f_op->read(file, (char *)start_addr, 473 ex.a_text + ex.a_data, &pos); 474 flush_icache_range((unsigned long) start_addr, 475 (unsigned long) start_addr + ex.a_text + ex.a_data); 476 477 retval = 0; 478 goto out; 479 } 480 /* Now use mmap to map the library into memory. */ 481 down_write(¤t->mm->mmap_sem); 482 error = do_mmap(file, start_addr, ex.a_text + ex.a_data, 483 PROT_READ | PROT_WRITE | PROT_EXEC, 484 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, 485 N_TXTOFF(ex)); 486 up_write(¤t->mm->mmap_sem); 487 retval = error; 488 if (error != start_addr) 489 goto out; 490 491 len = PAGE_ALIGN(ex.a_text + ex.a_data); 492 bss = ex.a_text + ex.a_data + ex.a_bss; 493 if (bss > len) { 494 error = do_brk(start_addr + len, bss - len); 495 retval = error; 496 if (error != start_addr + len) 497 goto out; 498 } 499 retval = 0; 500 out: 501 return retval; 502 } 503 504 static int __init init_aout_binfmt(void) 505 { 506 return register_binfmt(&aout_format); 507 } 508 509 static void __exit exit_aout_binfmt(void) 510 { 511 unregister_binfmt(&aout_format); 512 } 513 514 EXPORT_NO_SYMBOLS; 515 516 module_init(init_aout_binfmt); 517 module_exit(exit_aout_binfmt); 518 MODULE_LICENSE("GPL");
Cache object: 3237864729f67a01aac386502d28c471
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