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5
6#include <stdio.h>
7#include <stdlib.h>
8#include <stdarg.h>
9#include <unistd.h>
10#include <errno.h>
11#include <fcntl.h>
12#include <sched.h>
13#include <signal.h>
14#include <string.h>
15#include <sys/mman.h>
16#include <sys/stat.h>
17#include <sys/wait.h>
18#include <sys/time.h>
19#include <sys/resource.h>
20#include <asm/unistd.h>
21#include <init.h>
22#include <os.h>
23#include <mem_user.h>
24#include <ptrace_user.h>
25#include <registers.h>
26#include <skas.h>
27
28static void ptrace_child(void)
29{
30 int ret;
31
32 int pid = os_getpid(), ppid = getppid();
33 int sc_result;
34
35 if (change_sig(SIGWINCH, 0) < 0 ||
36 ptrace(PTRACE_TRACEME, 0, 0, 0) < 0) {
37 perror("ptrace");
38 kill(pid, SIGKILL);
39 }
40 kill(pid, SIGSTOP);
41
42
43
44
45
46 sc_result = os_getpid();
47
48 if (sc_result == pid)
49
50 ret = 1;
51 else if (sc_result == ppid)
52
53
54
55
56 ret = 0;
57 else
58
59
60
61
62 ret = 2;
63
64 exit(ret);
65}
66
67static void fatal_perror(const char *str)
68{
69 perror(str);
70 exit(1);
71}
72
73static void fatal(char *fmt, ...)
74{
75 va_list list;
76
77 va_start(list, fmt);
78 vfprintf(stderr, fmt, list);
79 va_end(list);
80
81 exit(1);
82}
83
84static void non_fatal(char *fmt, ...)
85{
86 va_list list;
87
88 va_start(list, fmt);
89 vfprintf(stderr, fmt, list);
90 va_end(list);
91}
92
93static int start_ptraced_child(void)
94{
95 int pid, n, status;
96
97 pid = fork();
98 if (pid == 0)
99 ptrace_child();
100 else if (pid < 0)
101 fatal_perror("start_ptraced_child : fork failed");
102
103 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
104 if (n < 0)
105 fatal_perror("check_ptrace : waitpid failed");
106 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
107 fatal("check_ptrace : expected SIGSTOP, got status = %d",
108 status);
109
110 return pid;
111}
112
113
114
115
116
117
118
119static int stop_ptraced_child(int pid, int exitcode, int mustexit)
120{
121 int status, n, ret = 0;
122
123 if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
124 perror("stop_ptraced_child : ptrace failed");
125 return -1;
126 }
127 CATCH_EINTR(n = waitpid(pid, &status, 0));
128 if (!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
129 int exit_with = WEXITSTATUS(status);
130 if (exit_with == 2)
131 non_fatal("check_ptrace : child exited with status 2. "
132 "\nDisabling SYSEMU support.\n");
133 non_fatal("check_ptrace : child exited with exitcode %d, while "
134 "expecting %d; status 0x%x\n", exit_with,
135 exitcode, status);
136 if (mustexit)
137 exit(1);
138 ret = -1;
139 }
140
141 return ret;
142}
143
144
145static int force_sysemu_disabled = 0;
146
147static int __init nosysemu_cmd_param(char *str, int* add)
148{
149 force_sysemu_disabled = 1;
150 return 0;
151}
152
153__uml_setup("nosysemu", nosysemu_cmd_param,
154"nosysemu\n"
155" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
156" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
157" behaviour of ptrace() and helps reducing host context switch rate.\n"
158" To make it working, you need a kernel patch for your host, too.\n"
159" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
160" information.\n\n");
161
162static void __init check_sysemu(void)
163{
164 unsigned long regs[MAX_REG_NR];
165 int pid, n, status, count=0;
166
167 non_fatal("Checking syscall emulation patch for ptrace...");
168 sysemu_supported = 0;
169 pid = start_ptraced_child();
170
171 if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
172 goto fail;
173
174 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
175 if (n < 0)
176 fatal_perror("check_sysemu : wait failed");
177 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
178 fatal("check_sysemu : expected SIGTRAP, got status = %d\n",
179 status);
180
181 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
182 fatal_perror("check_sysemu : PTRACE_GETREGS failed");
183 if (PT_SYSCALL_NR(regs) != __NR_getpid) {
184 non_fatal("check_sysemu got system call number %d, "
185 "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
186 goto fail;
187 }
188
189 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
190 if (n < 0) {
191 non_fatal("check_sysemu : failed to modify system call "
192 "return");
193 goto fail;
194 }
195
196 if (stop_ptraced_child(pid, 0, 0) < 0)
197 goto fail_stopped;
198
199 sysemu_supported = 1;
200 non_fatal("OK\n");
201 set_using_sysemu(!force_sysemu_disabled);
202
203 non_fatal("Checking advanced syscall emulation patch for ptrace...");
204 pid = start_ptraced_child();
205
206 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
207 (void *) PTRACE_O_TRACESYSGOOD) < 0))
208 fatal_perror("check_sysemu: PTRACE_OLDSETOPTIONS failed");
209
210 while (1) {
211 count++;
212 if (ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
213 goto fail;
214 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
215 if (n < 0)
216 fatal_perror("check_sysemu: wait failed");
217
218 if (WIFSTOPPED(status) &&
219 (WSTOPSIG(status) == (SIGTRAP|0x80))) {
220 if (!count) {
221 non_fatal("check_sysemu: SYSEMU_SINGLESTEP "
222 "doesn't singlestep");
223 goto fail;
224 }
225 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET,
226 os_getpid());
227 if (n < 0)
228 fatal_perror("check_sysemu : failed to modify "
229 "system call return");
230 break;
231 }
232 else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
233 count++;
234 else {
235 non_fatal("check_sysemu: expected SIGTRAP or "
236 "(SIGTRAP | 0x80), got status = %d\n",
237 status);
238 goto fail;
239 }
240 }
241 if (stop_ptraced_child(pid, 0, 0) < 0)
242 goto fail_stopped;
243
244 sysemu_supported = 2;
245 non_fatal("OK\n");
246
247 if (!force_sysemu_disabled)
248 set_using_sysemu(sysemu_supported);
249 return;
250
251fail:
252 stop_ptraced_child(pid, 1, 0);
253fail_stopped:
254 non_fatal("missing\n");
255}
256
257static void __init check_ptrace(void)
258{
259 int pid, syscall, n, status;
260
261 non_fatal("Checking that ptrace can change system call numbers...");
262 pid = start_ptraced_child();
263
264 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
265 (void *) PTRACE_O_TRACESYSGOOD) < 0))
266 fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
267
268 while (1) {
269 if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
270 fatal_perror("check_ptrace : ptrace failed");
271
272 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
273 if (n < 0)
274 fatal_perror("check_ptrace : wait failed");
275
276 if (!WIFSTOPPED(status) ||
277 (WSTOPSIG(status) != (SIGTRAP | 0x80)))
278 fatal("check_ptrace : expected (SIGTRAP|0x80), "
279 "got status = %d", status);
280
281 syscall = ptrace(PTRACE_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
282 0);
283 if (syscall == __NR_getpid) {
284 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
285 __NR_getppid);
286 if (n < 0)
287 fatal_perror("check_ptrace : failed to modify "
288 "system call");
289 break;
290 }
291 }
292 stop_ptraced_child(pid, 0, 1);
293 non_fatal("OK\n");
294 check_sysemu();
295}
296
297extern void check_tmpexec(void);
298
299static void __init check_coredump_limit(void)
300{
301 struct rlimit lim;
302 int err = getrlimit(RLIMIT_CORE, &lim);
303
304 if (err) {
305 perror("Getting core dump limit");
306 return;
307 }
308
309 printf("Core dump limits :\n\tsoft - ");
310 if (lim.rlim_cur == RLIM_INFINITY)
311 printf("NONE\n");
312 else printf("%lu\n", lim.rlim_cur);
313
314 printf("\thard - ");
315 if (lim.rlim_max == RLIM_INFINITY)
316 printf("NONE\n");
317 else printf("%lu\n", lim.rlim_max);
318}
319
320void __init os_early_checks(void)
321{
322 int pid;
323
324
325 check_coredump_limit();
326
327 check_ptrace();
328
329
330
331
332 check_tmpexec();
333
334 pid = start_ptraced_child();
335 if (init_registers(pid))
336 fatal("Failed to initialize default registers");
337 stop_ptraced_child(pid, 1, 1);
338}
339
340int __init parse_iomem(char *str, int *add)
341{
342 struct iomem_region *new;
343 struct stat64 buf;
344 char *file, *driver;
345 int fd, size;
346
347 driver = str;
348 file = strchr(str,',');
349 if (file == NULL) {
350 fprintf(stderr, "parse_iomem : failed to parse iomem\n");
351 goto out;
352 }
353 *file = '\0';
354 file++;
355 fd = open(file, O_RDWR, 0);
356 if (fd < 0) {
357 perror("parse_iomem - Couldn't open io file");
358 goto out;
359 }
360
361 if (fstat64(fd, &buf) < 0) {
362 perror("parse_iomem - cannot stat_fd file");
363 goto out_close;
364 }
365
366 new = malloc(sizeof(*new));
367 if (new == NULL) {
368 perror("Couldn't allocate iomem_region struct");
369 goto out_close;
370 }
371
372 size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
373
374 *new = ((struct iomem_region) { .next = iomem_regions,
375 .driver = driver,
376 .fd = fd,
377 .size = size,
378 .phys = 0,
379 .virt = 0 });
380 iomem_regions = new;
381 iomem_size += new->size + UM_KERN_PAGE_SIZE;
382
383 return 0;
384 out_close:
385 close(fd);
386 out:
387 return 1;
388}
389
