1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
4 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 */
6
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <unistd.h>
10 #include <errno.h>
11 #include <signal.h>
12 #include <fcntl.h>
13 #include <sys/mman.h>
14 #include <sys/ptrace.h>
15 #include <sys/wait.h>
16 #include <asm/unistd.h>
17 #include <init.h>
18 #include <longjmp.h>
19 #include <os.h>
20
21 #define ARBITRARY_ADDR -1
22 #define FAILURE_PID -1
23
24 #define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
25 #define COMM_SCANF "%*[^)])"
26
os_process_pc(int pid)27 unsigned long os_process_pc(int pid)
28 {
29 char proc_stat[STAT_PATH_LEN], buf[256];
30 unsigned long pc = ARBITRARY_ADDR;
31 int fd, err;
32
33 sprintf(proc_stat, "/proc/%d/stat", pid);
34 fd = open(proc_stat, O_RDONLY, 0);
35 if (fd < 0) {
36 printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', "
37 "errno = %d\n", proc_stat, errno);
38 goto out;
39 }
40 CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
41 if (err < 0) {
42 printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', "
43 "err = %d\n", proc_stat, errno);
44 goto out_close;
45 }
46 os_close_file(fd);
47 pc = ARBITRARY_ADDR;
48 if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
49 "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
50 "%*d %*d %*d %*d %*d %lu", &pc) != 1)
51 printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n",
52 buf);
53 out_close:
54 close(fd);
55 out:
56 return pc;
57 }
58
os_process_parent(int pid)59 int os_process_parent(int pid)
60 {
61 char stat[STAT_PATH_LEN];
62 char data[256];
63 int parent = FAILURE_PID, n, fd;
64
65 if (pid == -1)
66 return parent;
67
68 snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
69 fd = open(stat, O_RDONLY, 0);
70 if (fd < 0) {
71 printk(UM_KERN_ERR "Couldn't open '%s', errno = %d\n", stat,
72 errno);
73 return parent;
74 }
75
76 CATCH_EINTR(n = read(fd, data, sizeof(data)));
77 close(fd);
78
79 if (n < 0) {
80 printk(UM_KERN_ERR "Couldn't read '%s', errno = %d\n", stat,
81 errno);
82 return parent;
83 }
84
85 parent = FAILURE_PID;
86 n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
87 if (n != 1)
88 printk(UM_KERN_ERR "Failed to scan '%s'\n", data);
89
90 return parent;
91 }
92
os_alarm_process(int pid)93 void os_alarm_process(int pid)
94 {
95 kill(pid, SIGALRM);
96 }
97
os_stop_process(int pid)98 void os_stop_process(int pid)
99 {
100 kill(pid, SIGSTOP);
101 }
102
os_kill_process(int pid,int reap_child)103 void os_kill_process(int pid, int reap_child)
104 {
105 kill(pid, SIGKILL);
106 if (reap_child)
107 CATCH_EINTR(waitpid(pid, NULL, __WALL));
108 }
109
110 /* Kill off a ptraced child by all means available. kill it normally first,
111 * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
112 * which it can't exit directly.
113 */
114
os_kill_ptraced_process(int pid,int reap_child)115 void os_kill_ptraced_process(int pid, int reap_child)
116 {
117 kill(pid, SIGKILL);
118 ptrace(PTRACE_KILL, pid);
119 ptrace(PTRACE_CONT, pid);
120 if (reap_child)
121 CATCH_EINTR(waitpid(pid, NULL, __WALL));
122 }
123
124 /* Don't use the glibc version, which caches the result in TLS. It misses some
125 * syscalls, and also breaks with clone(), which does not unshare the TLS.
126 */
127
os_getpid(void)128 int os_getpid(void)
129 {
130 return syscall(__NR_getpid);
131 }
132
os_getpgrp(void)133 int os_getpgrp(void)
134 {
135 return getpgrp();
136 }
137
os_map_memory(void * virt,int fd,unsigned long long off,unsigned long len,int r,int w,int x)138 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
139 int r, int w, int x)
140 {
141 void *loc;
142 int prot;
143
144 prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
145 (x ? PROT_EXEC : 0);
146
147 loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
148 fd, off);
149 if (loc == MAP_FAILED)
150 return -errno;
151 return 0;
152 }
153
os_protect_memory(void * addr,unsigned long len,int r,int w,int x)154 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
155 {
156 int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
157 (x ? PROT_EXEC : 0));
158
159 if (mprotect(addr, len, prot) < 0)
160 return -errno;
161
162 return 0;
163 }
164
os_unmap_memory(void * addr,int len)165 int os_unmap_memory(void *addr, int len)
166 {
167 int err;
168
169 err = munmap(addr, len);
170 if (err < 0)
171 return -errno;
172 return 0;
173 }
174
175 #ifndef MADV_REMOVE
176 #define MADV_REMOVE KERNEL_MADV_REMOVE
177 #endif
178
os_drop_memory(void * addr,int length)179 int os_drop_memory(void *addr, int length)
180 {
181 int err;
182
183 err = madvise(addr, length, MADV_REMOVE);
184 if (err < 0)
185 err = -errno;
186 return err;
187 }
188
can_drop_memory(void)189 int __init can_drop_memory(void)
190 {
191 void *addr;
192 int fd, ok = 0;
193
194 printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
195 fd = create_mem_file(UM_KERN_PAGE_SIZE);
196 if (fd < 0) {
197 printk(UM_KERN_ERR "Creating test memory file failed, "
198 "err = %d\n", -fd);
199 goto out;
200 }
201
202 addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
203 MAP_SHARED, fd, 0);
204 if (addr == MAP_FAILED) {
205 printk(UM_KERN_ERR "Mapping test memory file failed, "
206 "err = %d\n", -errno);
207 goto out_close;
208 }
209
210 if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
211 printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
212 goto out_unmap;
213 }
214
215 printk(UM_KERN_CONT "OK\n");
216 ok = 1;
217
218 out_unmap:
219 munmap(addr, UM_KERN_PAGE_SIZE);
220 out_close:
221 close(fd);
222 out:
223 return ok;
224 }
225
os_page_mincore(void * addr)226 static int os_page_mincore(void *addr)
227 {
228 char vec[2];
229 int ret;
230
231 ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
232 if (ret < 0) {
233 if (errno == ENOMEM || errno == EINVAL)
234 return 0;
235 else
236 return -errno;
237 }
238
239 return vec[0] & 1;
240 }
241
os_mincore(void * addr,unsigned long len)242 int os_mincore(void *addr, unsigned long len)
243 {
244 char *vec;
245 int ret, i;
246
247 if (len <= UM_KERN_PAGE_SIZE)
248 return os_page_mincore(addr);
249
250 vec = calloc(1, (len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE);
251 if (!vec)
252 return -ENOMEM;
253
254 ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
255 if (ret < 0) {
256 if (errno == ENOMEM || errno == EINVAL)
257 ret = 0;
258 else
259 ret = -errno;
260
261 goto out;
262 }
263
264 for (i = 0; i < ((len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); i++) {
265 if (!(vec[i] & 1)) {
266 ret = 0;
267 goto out;
268 }
269 }
270
271 ret = 1;
272 out:
273 free(vec);
274 return ret;
275 }
276
init_new_thread_signals(void)277 void init_new_thread_signals(void)
278 {
279 set_handler(SIGSEGV);
280 set_handler(SIGTRAP);
281 set_handler(SIGFPE);
282 set_handler(SIGILL);
283 set_handler(SIGBUS);
284 signal(SIGHUP, SIG_IGN);
285 set_handler(SIGIO);
286 signal(SIGWINCH, SIG_IGN);
287 }
288