Merge rsync://bughost.org/repos/ieee80211-delta/
[linux-2.6] / arch / um / os-Linux / start_up.c
1 /*
2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5
6 #include <stdio.h>
7 #include <stddef.h>
8 #include <stdarg.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <unistd.h>
12 #include <signal.h>
13 #include <sched.h>
14 #include <fcntl.h>
15 #include <errno.h>
16 #include <setjmp.h>
17 #include <sys/time.h>
18 #include <sys/wait.h>
19 #include <sys/mman.h>
20 #include <asm/unistd.h>
21 #include <asm/page.h>
22 #include <sys/types.h>
23 #include "user_util.h"
24 #include "kern_util.h"
25 #include "user.h"
26 #include "signal_kern.h"
27 #include "signal_user.h"
28 #include "sysdep/ptrace.h"
29 #include "sysdep/sigcontext.h"
30 #include "irq_user.h"
31 #include "ptrace_user.h"
32 #include "mem_user.h"
33 #include "time_user.h"
34 #include "init.h"
35 #include "os.h"
36 #include "uml-config.h"
37 #include "choose-mode.h"
38 #include "mode.h"
39 #include "tempfile.h"
40 #include "kern_constants.h"
41
42 #ifdef UML_CONFIG_MODE_SKAS
43 #include "skas.h"
44 #include "skas_ptrace.h"
45 #include "registers.h"
46 #endif
47
48 static int ptrace_child(void *arg)
49 {
50         int ret;
51         int pid = os_getpid(), ppid = getppid();
52         int sc_result;
53
54         if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
55                 perror("ptrace");
56                 os_kill_process(pid, 0);
57         }
58         os_stop_process(pid);
59
60         /*This syscall will be intercepted by the parent. Don't call more than
61          * once, please.*/
62         sc_result = os_getpid();
63
64         if (sc_result == pid)
65                 ret = 1; /*Nothing modified by the parent, we are running
66                            normally.*/
67         else if (sc_result == ppid)
68                 ret = 0; /*Expected in check_ptrace and check_sysemu when they
69                            succeed in modifying the stack frame*/
70         else
71                 ret = 2; /*Serious trouble! This could be caused by a bug in
72                            host 2.6 SKAS3/2.6 patch before release -V6, together
73                            with a bug in the UML code itself.*/
74         _exit(ret);
75 }
76
77 static int start_ptraced_child(void **stack_out)
78 {
79         void *stack;
80         unsigned long sp;
81         int pid, n, status;
82
83         stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
84                      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
85         if(stack == MAP_FAILED)
86                 panic("check_ptrace : mmap failed, errno = %d", errno);
87         sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
88         pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
89         if(pid < 0)
90                 panic("start_ptraced_child : clone failed, errno = %d", errno);
91         CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
92         if(n < 0)
93                 panic("check_ptrace : clone failed, errno = %d", errno);
94         if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
95                 panic("check_ptrace : expected SIGSTOP, got status = %d",
96                       status);
97
98         *stack_out = stack;
99         return(pid);
100 }
101
102 /* When testing for SYSEMU support, if it is one of the broken versions, we
103  * must just avoid using sysemu, not panic, but only if SYSEMU features are
104  * broken.
105  * So only for SYSEMU features we test mustpanic, while normal host features
106  * must work anyway!
107  */
108 static int stop_ptraced_child(int pid, void *stack, int exitcode,
109                               int mustpanic)
110 {
111         int status, n, ret = 0;
112
113         if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
114                 panic("check_ptrace : ptrace failed, errno = %d", errno);
115         CATCH_EINTR(n = waitpid(pid, &status, 0));
116         if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
117                 int exit_with = WEXITSTATUS(status);
118                 if (exit_with == 2)
119                         printk("check_ptrace : child exited with status 2. "
120                                "Serious trouble happening! Try updating your "
121                                "host skas patch!\nDisabling SYSEMU support.");
122                 printk("check_ptrace : child exited with exitcode %d, while "
123                       "expecting %d; status 0x%x", exit_with,
124                       exitcode, status);
125                 if (mustpanic)
126                         panic("\n");
127                 else
128                         printk("\n");
129                 ret = -1;
130         }
131
132         if(munmap(stack, PAGE_SIZE) < 0)
133                 panic("check_ptrace : munmap failed, errno = %d", errno);
134         return ret;
135 }
136
137 int ptrace_faultinfo = 1;
138 int ptrace_ldt = 1;
139 int proc_mm = 1;
140 int skas_needs_stub = 0;
141
142 static int __init skas0_cmd_param(char *str, int* add)
143 {
144         ptrace_faultinfo = proc_mm = 0;
145         return 0;
146 }
147
148 /* The two __uml_setup would conflict, without this stupid alias. */
149
150 static int __init mode_skas0_cmd_param(char *str, int* add)
151         __attribute__((alias("skas0_cmd_param")));
152
153 __uml_setup("skas0", skas0_cmd_param,
154                 "skas0\n"
155                 "    Disables SKAS3 usage, so that SKAS0 is used, unless \n"
156                 "    you specify mode=tt.\n\n");
157
158 __uml_setup("mode=skas0", mode_skas0_cmd_param,
159                 "mode=skas0\n"
160                 "    Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
161                 "    specify mode=tt. Note that this was recently added - on \n"
162                 "    older kernels you must use simply \"skas0\".\n\n");
163
164 static int force_sysemu_disabled = 0;
165
166 static int __init nosysemu_cmd_param(char *str, int* add)
167 {
168         force_sysemu_disabled = 1;
169         return 0;
170 }
171
172 __uml_setup("nosysemu", nosysemu_cmd_param,
173 "nosysemu\n"
174 "    Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
175 "    SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
176 "    behaviour of ptrace() and helps reducing host context switch rate.\n"
177 "    To make it working, you need a kernel patch for your host, too.\n"
178 "    See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
179 "    information.\n\n");
180
181 static void __init check_sysemu(void)
182 {
183         void *stack;
184         int pid, n, status, count=0;
185
186         printk("Checking syscall emulation patch for ptrace...");
187         sysemu_supported = 0;
188         pid = start_ptraced_child(&stack);
189
190         if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
191                 goto fail;
192
193         CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
194         if (n < 0)
195                 panic("check_sysemu : wait failed, errno = %d", errno);
196         if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
197                 panic("check_sysemu : expected SIGTRAP, "
198                       "got status = %d", status);
199
200         n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
201                    os_getpid());
202         if(n < 0)
203                 panic("check_sysemu : failed to modify system "
204                       "call return, errno = %d", errno);
205
206         if (stop_ptraced_child(pid, stack, 0, 0) < 0)
207                 goto fail_stopped;
208
209         sysemu_supported = 1;
210         printk("OK\n");
211         set_using_sysemu(!force_sysemu_disabled);
212
213         printk("Checking advanced syscall emulation patch for ptrace...");
214         pid = start_ptraced_child(&stack);
215
216         if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
217                   (void *) PTRACE_O_TRACESYSGOOD) < 0)
218                 panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d",
219                       errno);
220
221         while(1){
222                 count++;
223                 if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
224                         goto fail;
225                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
226                 if(n < 0)
227                         panic("check_ptrace : wait failed, errno = %d", errno);
228                 if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))){
229                         if (!count)
230                                 panic("check_ptrace : SYSEMU_SINGLESTEP "
231                                       "doesn't singlestep");
232                         n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
233                                    os_getpid());
234                         if(n < 0)
235                                 panic("check_sysemu : failed to modify system "
236                                       "call return, errno = %d", errno);
237                         break;
238                 }
239                 else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
240                         count++;
241                 else
242                         panic("check_ptrace : expected SIGTRAP or "
243                               "(SIGTRAP|0x80), got status = %d", status);
244         }
245         if (stop_ptraced_child(pid, stack, 0, 0) < 0)
246                 goto fail_stopped;
247
248         sysemu_supported = 2;
249         printk("OK\n");
250
251         if ( !force_sysemu_disabled )
252                 set_using_sysemu(sysemu_supported);
253         return;
254
255 fail:
256         stop_ptraced_child(pid, stack, 1, 0);
257 fail_stopped:
258         printk("missing\n");
259 }
260
261 static void __init check_ptrace(void)
262 {
263         void *stack;
264         int pid, syscall, n, status;
265
266         printk("Checking that ptrace can change system call numbers...");
267         pid = start_ptraced_child(&stack);
268
269         if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
270                 panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", errno);
271
272         while(1){
273                 if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
274                         panic("check_ptrace : ptrace failed, errno = %d",
275                               errno);
276                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
277                 if(n < 0)
278                         panic("check_ptrace : wait failed, errno = %d", errno);
279                 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != (SIGTRAP|0x80)))
280                         panic("check_ptrace : expected (SIGTRAP|0x80), "
281                               "got status = %d", status);
282
283                 syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
284                                  0);
285                 if(syscall == __NR_getpid){
286                         n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
287                                    __NR_getppid);
288                         if(n < 0)
289                                 panic("check_ptrace : failed to modify system "
290                                       "call, errno = %d", errno);
291                         break;
292                 }
293         }
294         stop_ptraced_child(pid, stack, 0, 1);
295         printk("OK\n");
296         check_sysemu();
297 }
298
299 extern int create_tmp_file(unsigned long long len);
300
301 static void check_tmpexec(void)
302 {
303         void *addr;
304         int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
305
306         addr = mmap(NULL, UM_KERN_PAGE_SIZE,
307                     PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
308         printf("Checking PROT_EXEC mmap in /tmp...");
309         fflush(stdout);
310         if(addr == MAP_FAILED){
311                 err = errno;
312                 perror("failed");
313                 if(err == EPERM)
314                         printf("/tmp must be not mounted noexec\n");
315                 exit(1);
316         }
317         printf("OK\n");
318         munmap(addr, UM_KERN_PAGE_SIZE);
319
320         close(fd);
321 }
322
323 void os_early_checks(void)
324 {
325         check_ptrace();
326
327         /* Need to check this early because mmapping happens before the
328          * kernel is running.
329          */
330         check_tmpexec();
331 }
332
333 static int __init noprocmm_cmd_param(char *str, int* add)
334 {
335         proc_mm = 0;
336         return 0;
337 }
338
339 __uml_setup("noprocmm", noprocmm_cmd_param,
340 "noprocmm\n"
341 "    Turns off usage of /proc/mm, even if host supports it.\n"
342 "    To support /proc/mm, the host needs to be patched using\n"
343 "    the current skas3 patch.\n\n");
344
345 static int __init noptracefaultinfo_cmd_param(char *str, int* add)
346 {
347         ptrace_faultinfo = 0;
348         return 0;
349 }
350
351 __uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
352 "noptracefaultinfo\n"
353 "    Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
354 "    it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
355 "    using the current skas3 patch.\n\n");
356
357 static int __init noptraceldt_cmd_param(char *str, int* add)
358 {
359         ptrace_ldt = 0;
360         return 0;
361 }
362
363 __uml_setup("noptraceldt", noptraceldt_cmd_param,
364 "noptraceldt\n"
365 "    Turns off usage of PTRACE_LDT, even if host supports it.\n"
366 "    To support PTRACE_LDT, the host needs to be patched using\n"
367 "    the current skas3 patch.\n\n");
368
369 #ifdef UML_CONFIG_MODE_SKAS
370 static inline void check_skas3_ptrace_faultinfo(void)
371 {
372         struct ptrace_faultinfo fi;
373         void *stack;
374         int pid, n;
375
376         printf("  - PTRACE_FAULTINFO...");
377         pid = start_ptraced_child(&stack);
378
379         n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
380         if (n < 0) {
381                 ptrace_faultinfo = 0;
382                 if(errno == EIO)
383                         printf("not found\n");
384                 else
385                         perror("not found");
386         }
387         else {
388                 if (!ptrace_faultinfo)
389                         printf("found but disabled on command line\n");
390                 else
391                         printf("found\n");
392         }
393
394         init_registers(pid);
395         stop_ptraced_child(pid, stack, 1, 1);
396 }
397
398 static inline void check_skas3_ptrace_ldt(void)
399 {
400 #ifdef PTRACE_LDT
401         void *stack;
402         int pid, n;
403         unsigned char ldtbuf[40];
404         struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
405                 .func = 2, /* read default ldt */
406                 .ptr = ldtbuf,
407                 .bytecount = sizeof(ldtbuf)};
408
409         printf("  - PTRACE_LDT...");
410         pid = start_ptraced_child(&stack);
411
412         n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
413         if (n < 0) {
414                 if(errno == EIO)
415                         printf("not found\n");
416                 else {
417                         perror("not found");
418                 }
419                 ptrace_ldt = 0;
420         }
421         else {
422                 if(ptrace_ldt)
423                         printf("found\n");
424                 else
425                         printf("found, but use is disabled\n");
426         }
427
428         stop_ptraced_child(pid, stack, 1, 1);
429 #else
430         /* PTRACE_LDT might be disabled via cmdline option.
431          * We want to override this, else we might use the stub
432          * without real need
433          */
434         ptrace_ldt = 1;
435 #endif
436 }
437
438 static inline void check_skas3_proc_mm(void)
439 {
440         printf("  - /proc/mm...");
441         if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
442                 proc_mm = 0;
443                 printf("not found\n");
444         }
445         else {
446                 if (!proc_mm)
447                         printf("found but disabled on command line\n");
448                 else
449                         printf("found\n");
450         }
451 }
452
453 int can_do_skas(void)
454 {
455         printf("Checking for the skas3 patch in the host:\n");
456
457         check_skas3_proc_mm();
458         check_skas3_ptrace_faultinfo();
459         check_skas3_ptrace_ldt();
460
461         if(!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
462                 skas_needs_stub = 1;
463
464         return 1;
465 }
466 #else
467 int can_do_skas(void)
468 {
469         return(0);
470 }
471 #endif
472
473 int have_devanon = 0;
474
475 void check_devanon(void)
476 {
477         int fd;
478
479         printk("Checking for /dev/anon on the host...");
480         fd = open("/dev/anon", O_RDWR);
481         if(fd < 0){
482                 printk("Not available (open failed with errno %d)\n", errno);
483                 return;
484         }
485
486         printk("OK\n");
487         have_devanon = 1;
488 }
489
490 int __init parse_iomem(char *str, int *add)
491 {
492         struct iomem_region *new;
493         struct uml_stat buf;
494         char *file, *driver;
495         int fd, err, size;
496
497         driver = str;
498         file = strchr(str,',');
499         if(file == NULL){
500                 printf("parse_iomem : failed to parse iomem\n");
501                 goto out;
502         }
503         *file = '\0';
504         file++;
505         fd = os_open_file(file, of_rdwr(OPENFLAGS()), 0);
506         if(fd < 0){
507                 os_print_error(fd, "parse_iomem - Couldn't open io file");
508                 goto out;
509         }
510
511         err = os_stat_fd(fd, &buf);
512         if(err < 0){
513                 os_print_error(err, "parse_iomem - cannot stat_fd file");
514                 goto out_close;
515         }
516
517         new = malloc(sizeof(*new));
518         if(new == NULL){
519                 perror("Couldn't allocate iomem_region struct");
520                 goto out_close;
521         }
522
523         size = (buf.ust_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
524
525         *new = ((struct iomem_region) { .next           = iomem_regions,
526                                         .driver         = driver,
527                                         .fd             = fd,
528                                         .size           = size,
529                                         .phys           = 0,
530                                         .virt           = 0 });
531         iomem_regions = new;
532         iomem_size += new->size + UM_KERN_PAGE_SIZE;
533
534         return(0);
535  out_close:
536         os_close_file(fd);
537  out:
538         return(1);
539 }
540