1 /*
2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include <signal.h>
10 #include <fcntl.h>
11 #include <sys/mman.h>
12 #include <sys/ptrace.h>
13 #include <sys/wait.h>
14 #include <asm/unistd.h>
15 #include "init.h"
16 #include "kern_constants.h"
17 #include "longjmp.h"
18 #include "os.h"
19 #include "process.h"
20 #include "skas_ptrace.h"
21 #include "user.h"
22
23 #define ARBITRARY_ADDR -1
24 #define FAILURE_PID -1
25
26 #define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
27 #define COMM_SCANF "%*[^)])"
28
29 unsigned long os_process_pc(int pid)
30 {
31 char proc_stat[STAT_PATH_LEN], buf[256];
32 unsigned long pc = ARBITRARY_ADDR;
33 int fd, err;
34
35 sprintf(proc_stat, "/proc/%d/stat", pid);
36 fd = open(proc_stat, O_RDONLY, 0);
37 if (fd < 0) {
38 printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', "
39 "errno = %d\n", proc_stat, errno);
40 goto out;
41 }
42 CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
43 if (err < 0) {
44 printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', "
45 "err = %d\n", proc_stat, errno);
46 goto out_close;
47 }
48 os_close_file(fd);
49 pc = ARBITRARY_ADDR;
50 if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
51 "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
52 "%*d %*d %*d %*d %*d %lu", &pc) != 1)
53 printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n",
54 buf);
55 out_close:
56 close(fd);
57 out:
58 return pc;
59 }
60
61 int os_process_parent(int pid)
62 {
63 char stat[STAT_PATH_LEN];
64 char data[256];
65 int parent = FAILURE_PID, n, fd;
66
67 if (pid == -1)
68 return parent;
69
70 snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
71 fd = open(stat, O_RDONLY, 0);
72 if (fd < 0) {
73 printk(UM_KERN_ERR "Couldn't open '%s', errno = %d\n", stat,
74 errno);
75 return parent;
76 }
77
78 CATCH_EINTR(n = read(fd, data, sizeof(data)));
79 close(fd);
80
81 if (n < 0) {
82 printk(UM_KERN_ERR "Couldn't read '%s', errno = %d\n", stat,
83 errno);
84 return parent;
85 }
86
87 parent = FAILURE_PID;
88 n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
89 if (n != 1)
90 printk(UM_KERN_ERR "Failed to scan '%s'\n", data);
91
92 return parent;
93 }
94
95 void os_stop_process(int pid)
96 {
97 kill(pid, SIGSTOP);
98 }
99
100 void os_kill_process(int pid, int reap_child)
101 {
102 kill(pid, SIGKILL);
103 if (reap_child)
104 CATCH_EINTR(waitpid(pid, NULL, __WALL));
105 }
106
107 /* This is here uniquely to have access to the userspace errno, i.e. the one
108 * used by ptrace in case of error.
109 */
110
111 long os_ptrace_ldt(long pid, long addr, long data)
112 {
113 int ret;
114
115 ret = ptrace(PTRACE_LDT, pid, addr, data);
116
117 if (ret < 0)
118 return -errno;
119 return ret;
120 }
121
122 /* Kill off a ptraced child by all means available. kill it normally first,
123 * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
124 * which it can't exit directly.
125 */
126
127 void os_kill_ptraced_process(int pid, int reap_child)
128 {
129 kill(pid, SIGKILL);
130 ptrace(PTRACE_KILL, pid);
131 ptrace(PTRACE_CONT, pid);
132 if (reap_child)
133 CATCH_EINTR(waitpid(pid, NULL, __WALL));
134 }
135
136 /* Don't use the glibc version, which caches the result in TLS. It misses some
137 * syscalls, and also breaks with clone(), which does not unshare the TLS.
138 */
139
140 int os_getpid(void)
141 {
142 return syscall(__NR_getpid);
143 }
144
145 int os_getpgrp(void)
146 {
147 return getpgrp();
148 }
149
150 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
151 int r, int w, int x)
152 {
153 void *loc;
154 int prot;
155
156 prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
157 (x ? PROT_EXEC : 0);
158
159 loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
160 fd, off);
161 if (loc == MAP_FAILED)
162 return -errno;
163 return 0;
164 }
165
166 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
167 {
168 int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
169 (x ? PROT_EXEC : 0));
170
171 if (mprotect(addr, len, prot) < 0)
172 return -errno;
173
174 return 0;
175 }
176
177 int os_unmap_memory(void *addr, int len)
178 {
179 int err;
180
181 err = munmap(addr, len);
182 if (err < 0)
183 return -errno;
184 return 0;
185 }
186
187 #ifndef MADV_REMOVE
188 #define MADV_REMOVE KERNEL_MADV_REMOVE
189 #endif
190
191 int os_drop_memory(void *addr, int length)
192 {
193 int err;
194
195 err = madvise(addr, length, MADV_REMOVE);
196 if (err < 0)
197 err = -errno;
198 return err;
199 }
200
201 int __init can_drop_memory(void)
202 {
203 void *addr;
204 int fd, ok = 0;
205
206 printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
207 fd = create_mem_file(UM_KERN_PAGE_SIZE);
208 if (fd < 0) {
209 printk(UM_KERN_ERR "Creating test memory file failed, "
210 "err = %d\n", -fd);
211 goto out;
212 }
213
214 addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
215 MAP_SHARED, fd, 0);
216 if (addr == MAP_FAILED) {
217 printk(UM_KERN_ERR "Mapping test memory file failed, "
218 "err = %d\n", -errno);
219 goto out_close;
220 }
221
222 if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
223 printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
224 goto out_unmap;
225 }
226
227 printk(UM_KERN_CONT "OK\n");
228 ok = 1;
229
230 out_unmap:
231 munmap(addr, UM_KERN_PAGE_SIZE);
232 out_close:
233 close(fd);
234 out:
235 return ok;
236 }
237
238 void init_new_thread_signals(void)
239 {
240 set_handler(SIGSEGV, (__sighandler_t) sig_handler, SA_ONSTACK,
241 SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
242 set_handler(SIGTRAP, (__sighandler_t) sig_handler, SA_ONSTACK,
243 SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
244 set_handler(SIGFPE, (__sighandler_t) sig_handler, SA_ONSTACK,
245 SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
246 set_handler(SIGILL, (__sighandler_t) sig_handler, SA_ONSTACK,
247 SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
248 set_handler(SIGBUS, (__sighandler_t) sig_handler, SA_ONSTACK,
249 SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
250 signal(SIGHUP, SIG_IGN);
251
252 set_handler(SIGIO, (__sighandler_t) sig_handler,
253 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGALRM,
254 SIGVTALRM, -1);
255 signal(SIGWINCH, SIG_IGN);
256 }
257
258 int run_kernel_thread(int (*fn)(void *), void *arg, jmp_buf **jmp_ptr)
259 {
260 jmp_buf buf;
261 int n;
262
263 *jmp_ptr = &buf;
264 n = UML_SETJMP(&buf);
265 if (n != 0)
266 return n;
267 (*fn)(arg);
268 return 0;
269 }
270
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