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/prctl.h>
16 #include <sys/wait.h>
17 #include <asm/unistd.h>
18 #include <init.h>
19 #include <longjmp.h>
20 #include <os.h>
21
os_alarm_process(int pid)22 void os_alarm_process(int pid)
23 {
24 kill(pid, SIGALRM);
25 }
26
os_kill_process(int pid,int reap_child)27 void os_kill_process(int pid, int reap_child)
28 {
29 kill(pid, SIGKILL);
30 if (reap_child)
31 CATCH_EINTR(waitpid(pid, NULL, __WALL));
32 }
33
34 /* Kill off a ptraced child by all means available. kill it normally first,
35 * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
36 * which it can't exit directly.
37 */
38
os_kill_ptraced_process(int pid,int reap_child)39 void os_kill_ptraced_process(int pid, int reap_child)
40 {
41 kill(pid, SIGKILL);
42 ptrace(PTRACE_KILL, pid);
43 ptrace(PTRACE_CONT, pid);
44 if (reap_child)
45 CATCH_EINTR(waitpid(pid, NULL, __WALL));
46 }
47
48 /* Don't use the glibc version, which caches the result in TLS. It misses some
49 * syscalls, and also breaks with clone(), which does not unshare the TLS.
50 */
51
os_getpid(void)52 int os_getpid(void)
53 {
54 return syscall(__NR_getpid);
55 }
56
os_map_memory(void * virt,int fd,unsigned long long off,unsigned long len,int r,int w,int x)57 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
58 int r, int w, int x)
59 {
60 void *loc;
61 int prot;
62
63 prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
64 (x ? PROT_EXEC : 0);
65
66 loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
67 fd, off);
68 if (loc == MAP_FAILED)
69 return -errno;
70 return 0;
71 }
72
os_protect_memory(void * addr,unsigned long len,int r,int w,int x)73 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
74 {
75 int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
76 (x ? PROT_EXEC : 0));
77
78 if (mprotect(addr, len, prot) < 0)
79 return -errno;
80
81 return 0;
82 }
83
os_unmap_memory(void * addr,int len)84 int os_unmap_memory(void *addr, int len)
85 {
86 int err;
87
88 err = munmap(addr, len);
89 if (err < 0)
90 return -errno;
91 return 0;
92 }
93
94 #ifndef MADV_REMOVE
95 #define MADV_REMOVE KERNEL_MADV_REMOVE
96 #endif
97
os_drop_memory(void * addr,int length)98 int os_drop_memory(void *addr, int length)
99 {
100 int err;
101
102 err = madvise(addr, length, MADV_REMOVE);
103 if (err < 0)
104 err = -errno;
105 return err;
106 }
107
can_drop_memory(void)108 int __init can_drop_memory(void)
109 {
110 void *addr;
111 int fd, ok = 0;
112
113 printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
114 fd = create_mem_file(UM_KERN_PAGE_SIZE);
115 if (fd < 0) {
116 printk(UM_KERN_ERR "Creating test memory file failed, "
117 "err = %d\n", -fd);
118 goto out;
119 }
120
121 addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
122 MAP_SHARED, fd, 0);
123 if (addr == MAP_FAILED) {
124 printk(UM_KERN_ERR "Mapping test memory file failed, "
125 "err = %d\n", -errno);
126 goto out_close;
127 }
128
129 if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
130 printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
131 goto out_unmap;
132 }
133
134 printk(UM_KERN_CONT "OK\n");
135 ok = 1;
136
137 out_unmap:
138 munmap(addr, UM_KERN_PAGE_SIZE);
139 out_close:
140 close(fd);
141 out:
142 return ok;
143 }
144
os_page_mincore(void * addr)145 static int os_page_mincore(void *addr)
146 {
147 char vec[2];
148 int ret;
149
150 ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
151 if (ret < 0) {
152 if (errno == ENOMEM || errno == EINVAL)
153 return 0;
154 else
155 return -errno;
156 }
157
158 return vec[0] & 1;
159 }
160
os_mincore(void * addr,unsigned long len)161 int os_mincore(void *addr, unsigned long len)
162 {
163 char *vec;
164 int ret, i;
165
166 if (len <= UM_KERN_PAGE_SIZE)
167 return os_page_mincore(addr);
168
169 vec = calloc(1, (len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE);
170 if (!vec)
171 return -ENOMEM;
172
173 ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
174 if (ret < 0) {
175 if (errno == ENOMEM || errno == EINVAL)
176 ret = 0;
177 else
178 ret = -errno;
179
180 goto out;
181 }
182
183 for (i = 0; i < ((len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); i++) {
184 if (!(vec[i] & 1)) {
185 ret = 0;
186 goto out;
187 }
188 }
189
190 ret = 1;
191 out:
192 free(vec);
193 return ret;
194 }
195
init_new_thread_signals(void)196 void init_new_thread_signals(void)
197 {
198 set_handler(SIGSEGV);
199 set_handler(SIGTRAP);
200 set_handler(SIGFPE);
201 set_handler(SIGILL);
202 set_handler(SIGBUS);
203 signal(SIGHUP, SIG_IGN);
204 set_handler(SIGIO);
205 signal(SIGWINCH, SIG_IGN);
206 }
207
os_set_pdeathsig(void)208 void os_set_pdeathsig(void)
209 {
210 prctl(PR_SET_PDEATHSIG, SIGKILL);
211 }
212