ARM: report present cpus instead of online CPUs
[linux-2.6.git] / fs / binfmt_aout.c
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/time.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/binfmts.h>
24 #include <linux/personality.h>
25 #include <linux/init.h>
26 #include <linux/coredump.h>
27 #include <linux/slab.h>
28
29 #include <asm/system.h>
30 #include <asm/uaccess.h>
31 #include <asm/cacheflush.h>
32 #include <asm/a.out-core.h>
33
34 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
35 static int load_aout_library(struct file*);
36 static int aout_core_dump(struct coredump_params *cprm);
37
38 static struct linux_binfmt aout_format = {
39         .module         = THIS_MODULE,
40         .load_binary    = load_aout_binary,
41         .load_shlib     = load_aout_library,
42         .core_dump      = aout_core_dump,
43         .min_coredump   = PAGE_SIZE
44 };
45
46 #define BAD_ADDR(x)     ((unsigned long)(x) >= TASK_SIZE)
47
48 static int set_brk(unsigned long start, unsigned long end)
49 {
50         start = PAGE_ALIGN(start);
51         end = PAGE_ALIGN(end);
52         if (end > start) {
53                 unsigned long addr;
54                 down_write(&current->mm->mmap_sem);
55                 addr = do_brk(start, end - start);
56                 up_write(&current->mm->mmap_sem);
57                 if (BAD_ADDR(addr))
58                         return addr;
59         }
60         return 0;
61 }
62
63 /*
64  * Routine writes a core dump image in the current directory.
65  * Currently only a stub-function.
66  *
67  * Note that setuid/setgid files won't make a core-dump if the uid/gid
68  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
69  * field, which also makes sure the core-dumps won't be recursive if the
70  * dumping of the process results in another error..
71  */
72
73 static int aout_core_dump(struct coredump_params *cprm)
74 {
75         struct file *file = cprm->file;
76         mm_segment_t fs;
77         int has_dumped = 0;
78         void __user *dump_start;
79         int dump_size;
80         struct user dump;
81 #ifdef __alpha__
82 #       define START_DATA(u)    ((void __user *)u.start_data)
83 #else
84 #       define START_DATA(u)    ((void __user *)((u.u_tsize << PAGE_SHIFT) + \
85                                  u.start_code))
86 #endif
87 #       define START_STACK(u)   ((void __user *)u.start_stack)
88
89         fs = get_fs();
90         set_fs(KERNEL_DS);
91         has_dumped = 1;
92         current->flags |= PF_DUMPCORE;
93         strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
94         dump.u_ar0 = offsetof(struct user, regs);
95         dump.signal = cprm->signr;
96         aout_dump_thread(cprm->regs, &dump);
97
98 /* If the size of the dump file exceeds the rlimit, then see what would happen
99    if we wrote the stack, but not the data area.  */
100         if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
101                 dump.u_dsize = 0;
102
103 /* Make sure we have enough room to write the stack and data areas. */
104         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
105                 dump.u_ssize = 0;
106
107 /* make sure we actually have a data and stack area to dump */
108         set_fs(USER_DS);
109         if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
110                 dump.u_dsize = 0;
111         if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
112                 dump.u_ssize = 0;
113
114         set_fs(KERNEL_DS);
115 /* struct user */
116         if (!dump_write(file, &dump, sizeof(dump)))
117                 goto end_coredump;
118 /* Now dump all of the user data.  Include malloced stuff as well */
119         if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
120                 goto end_coredump;
121 /* now we start writing out the user space info */
122         set_fs(USER_DS);
123 /* Dump the data area */
124         if (dump.u_dsize != 0) {
125                 dump_start = START_DATA(dump);
126                 dump_size = dump.u_dsize << PAGE_SHIFT;
127                 if (!dump_write(file, dump_start, dump_size))
128                         goto end_coredump;
129         }
130 /* Now prepare to dump the stack area */
131         if (dump.u_ssize != 0) {
132                 dump_start = START_STACK(dump);
133                 dump_size = dump.u_ssize << PAGE_SHIFT;
134                 if (!dump_write(file, dump_start, dump_size))
135                         goto end_coredump;
136         }
137 end_coredump:
138         set_fs(fs);
139         return has_dumped;
140 }
141
142 /*
143  * create_aout_tables() parses the env- and arg-strings in new user
144  * memory and creates the pointer tables from them, and puts their
145  * addresses on the "stack", returning the new stack pointer value.
146  */
147 static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
148 {
149         char __user * __user *argv;
150         char __user * __user *envp;
151         unsigned long __user *sp;
152         int argc = bprm->argc;
153         int envc = bprm->envc;
154
155         sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
156 #ifdef __alpha__
157 /* whee.. test-programs are so much fun. */
158         put_user(0, --sp);
159         put_user(0, --sp);
160         if (bprm->loader) {
161                 put_user(0, --sp);
162                 put_user(1003, --sp);
163                 put_user(bprm->loader, --sp);
164                 put_user(1002, --sp);
165         }
166         put_user(bprm->exec, --sp);
167         put_user(1001, --sp);
168 #endif
169         sp -= envc+1;
170         envp = (char __user * __user *) sp;
171         sp -= argc+1;
172         argv = (char __user * __user *) sp;
173 #ifndef __alpha__
174         put_user((unsigned long) envp,--sp);
175         put_user((unsigned long) argv,--sp);
176 #endif
177         put_user(argc,--sp);
178         current->mm->arg_start = (unsigned long) p;
179         while (argc-->0) {
180                 char c;
181                 put_user(p,argv++);
182                 do {
183                         get_user(c,p++);
184                 } while (c);
185         }
186         put_user(NULL,argv);
187         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
188         while (envc-->0) {
189                 char c;
190                 put_user(p,envp++);
191                 do {
192                         get_user(c,p++);
193                 } while (c);
194         }
195         put_user(NULL,envp);
196         current->mm->env_end = (unsigned long) p;
197         return sp;
198 }
199
200 /*
201  * These are the functions used to load a.out style executables and shared
202  * libraries.  There is no binary dependent code anywhere else.
203  */
204
205 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
206 {
207         struct exec ex;
208         unsigned long error;
209         unsigned long fd_offset;
210         unsigned long rlim;
211         int retval;
212
213         ex = *((struct exec *) bprm->buf);              /* exec-header */
214         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
215              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
216             N_TRSIZE(ex) || N_DRSIZE(ex) ||
217             i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
218                 return -ENOEXEC;
219         }
220
221         /*
222          * Requires a mmap handler. This prevents people from using a.out
223          * as part of an exploit attack against /proc-related vulnerabilities.
224          */
225         if (!bprm->file->f_op || !bprm->file->f_op->mmap)
226                 return -ENOEXEC;
227
228         fd_offset = N_TXTOFF(ex);
229
230         /* Check initial limits. This avoids letting people circumvent
231          * size limits imposed on them by creating programs with large
232          * arrays in the data or bss.
233          */
234         rlim = rlimit(RLIMIT_DATA);
235         if (rlim >= RLIM_INFINITY)
236                 rlim = ~0;
237         if (ex.a_data + ex.a_bss > rlim)
238                 return -ENOMEM;
239
240         /* Flush all traces of the currently running executable */
241         retval = flush_old_exec(bprm);
242         if (retval)
243                 return retval;
244
245         /* OK, This is the point of no return */
246 #ifdef __alpha__
247         SET_AOUT_PERSONALITY(bprm, ex);
248 #else
249         set_personality(PER_LINUX);
250 #endif
251         setup_new_exec(bprm);
252
253         current->mm->end_code = ex.a_text +
254                 (current->mm->start_code = N_TXTADDR(ex));
255         current->mm->end_data = ex.a_data +
256                 (current->mm->start_data = N_DATADDR(ex));
257         current->mm->brk = ex.a_bss +
258                 (current->mm->start_brk = N_BSSADDR(ex));
259         current->mm->free_area_cache = current->mm->mmap_base;
260         current->mm->cached_hole_size = 0;
261
262         install_exec_creds(bprm);
263         current->flags &= ~PF_FORKNOEXEC;
264
265         if (N_MAGIC(ex) == OMAGIC) {
266                 unsigned long text_addr, map_size;
267                 loff_t pos;
268
269                 text_addr = N_TXTADDR(ex);
270
271 #ifdef __alpha__
272                 pos = fd_offset;
273                 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
274 #else
275                 pos = 32;
276                 map_size = ex.a_text+ex.a_data;
277 #endif
278                 down_write(&current->mm->mmap_sem);
279                 error = do_brk(text_addr & PAGE_MASK, map_size);
280                 up_write(&current->mm->mmap_sem);
281                 if (error != (text_addr & PAGE_MASK)) {
282                         send_sig(SIGKILL, current, 0);
283                         return error;
284                 }
285
286                 error = bprm->file->f_op->read(bprm->file,
287                           (char __user *)text_addr,
288                           ex.a_text+ex.a_data, &pos);
289                 if ((signed long)error < 0) {
290                         send_sig(SIGKILL, current, 0);
291                         return error;
292                 }
293                          
294                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
295         } else {
296                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
297                     (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
298                 {
299                         printk(KERN_NOTICE "executable not page aligned\n");
300                 }
301
302                 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
303                 {
304                         printk(KERN_WARNING 
305                                "fd_offset is not page aligned. Please convert program: %s\n",
306                                bprm->file->f_path.dentry->d_name.name);
307                 }
308
309                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
310                         loff_t pos = fd_offset;
311                         down_write(&current->mm->mmap_sem);
312                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
313                         up_write(&current->mm->mmap_sem);
314                         bprm->file->f_op->read(bprm->file,
315                                         (char __user *)N_TXTADDR(ex),
316                                         ex.a_text+ex.a_data, &pos);
317                         flush_icache_range((unsigned long) N_TXTADDR(ex),
318                                            (unsigned long) N_TXTADDR(ex) +
319                                            ex.a_text+ex.a_data);
320                         goto beyond_if;
321                 }
322
323                 down_write(&current->mm->mmap_sem);
324                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
325                         PROT_READ | PROT_EXEC,
326                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
327                         fd_offset);
328                 up_write(&current->mm->mmap_sem);
329
330                 if (error != N_TXTADDR(ex)) {
331                         send_sig(SIGKILL, current, 0);
332                         return error;
333                 }
334
335                 down_write(&current->mm->mmap_sem);
336                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
337                                 PROT_READ | PROT_WRITE | PROT_EXEC,
338                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
339                                 fd_offset + ex.a_text);
340                 up_write(&current->mm->mmap_sem);
341                 if (error != N_DATADDR(ex)) {
342                         send_sig(SIGKILL, current, 0);
343                         return error;
344                 }
345         }
346 beyond_if:
347         set_binfmt(&aout_format);
348
349         retval = set_brk(current->mm->start_brk, current->mm->brk);
350         if (retval < 0) {
351                 send_sig(SIGKILL, current, 0);
352                 return retval;
353         }
354
355         retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
356         if (retval < 0) { 
357                 /* Someone check-me: is this error path enough? */ 
358                 send_sig(SIGKILL, current, 0); 
359                 return retval;
360         }
361
362         current->mm->start_stack =
363                 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
364 #ifdef __alpha__
365         regs->gp = ex.a_gpvalue;
366 #endif
367         start_thread(regs, ex.a_entry, current->mm->start_stack);
368         return 0;
369 }
370
371 static int load_aout_library(struct file *file)
372 {
373         struct inode * inode;
374         unsigned long bss, start_addr, len;
375         unsigned long error;
376         int retval;
377         struct exec ex;
378
379         inode = file->f_path.dentry->d_inode;
380
381         retval = -ENOEXEC;
382         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
383         if (error != sizeof(ex))
384                 goto out;
385
386         /* We come in here for the regular a.out style of shared libraries */
387         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
388             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
389             i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
390                 goto out;
391         }
392
393         /*
394          * Requires a mmap handler. This prevents people from using a.out
395          * as part of an exploit attack against /proc-related vulnerabilities.
396          */
397         if (!file->f_op || !file->f_op->mmap)
398                 goto out;
399
400         if (N_FLAGS(ex))
401                 goto out;
402
403         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
404            this off to get the starting address for the page */
405
406         start_addr =  ex.a_entry & 0xfffff000;
407
408         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
409                 loff_t pos = N_TXTOFF(ex);
410
411                 if (printk_ratelimit())
412                 {
413                         printk(KERN_WARNING 
414                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
415                                file->f_path.dentry->d_name.name);
416                 }
417                 down_write(&current->mm->mmap_sem);
418                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
419                 up_write(&current->mm->mmap_sem);
420                 
421                 file->f_op->read(file, (char __user *)start_addr,
422                         ex.a_text + ex.a_data, &pos);
423                 flush_icache_range((unsigned long) start_addr,
424                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
425
426                 retval = 0;
427                 goto out;
428         }
429         /* Now use mmap to map the library into memory. */
430         down_write(&current->mm->mmap_sem);
431         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
432                         PROT_READ | PROT_WRITE | PROT_EXEC,
433                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
434                         N_TXTOFF(ex));
435         up_write(&current->mm->mmap_sem);
436         retval = error;
437         if (error != start_addr)
438                 goto out;
439
440         len = PAGE_ALIGN(ex.a_text + ex.a_data);
441         bss = ex.a_text + ex.a_data + ex.a_bss;
442         if (bss > len) {
443                 down_write(&current->mm->mmap_sem);
444                 error = do_brk(start_addr + len, bss - len);
445                 up_write(&current->mm->mmap_sem);
446                 retval = error;
447                 if (error != start_addr + len)
448                         goto out;
449         }
450         retval = 0;
451 out:
452         return retval;
453 }
454
455 static int __init init_aout_binfmt(void)
456 {
457         return register_binfmt(&aout_format);
458 }
459
460 static void __exit exit_aout_binfmt(void)
461 {
462         unregister_binfmt(&aout_format);
463 }
464
465 core_initcall(init_aout_binfmt);
466 module_exit(exit_aout_binfmt);
467 MODULE_LICENSE("GPL");