Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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#include <skas/skas.h>
22
23void os_alarm_process(int pid)
24{
25 if (pid <= 0)
26 return;
27
28 kill(pid, SIGALRM);
29}
30
31void os_kill_process(int pid, int reap_child)
32{
33 if (pid <= 0)
34 return;
35
36 /* Block signals until child is reaped */
37 block_signals();
38
39 kill(pid, SIGKILL);
40 if (reap_child)
41 CATCH_EINTR(waitpid(pid, NULL, __WALL));
42
43 unblock_signals();
44}
45
46/* Kill off a ptraced child by all means available. kill it normally first,
47 * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
48 * which it can't exit directly.
49 */
50
51void os_kill_ptraced_process(int pid, int reap_child)
52{
53 if (pid <= 0)
54 return;
55
56 /* Block signals until child is reaped */
57 block_signals();
58
59 kill(pid, SIGKILL);
60 ptrace(PTRACE_KILL, pid);
61 ptrace(PTRACE_CONT, pid);
62 if (reap_child)
63 CATCH_EINTR(waitpid(pid, NULL, __WALL));
64
65 unblock_signals();
66}
67
68pid_t os_reap_child(void)
69{
70 int status;
71
72 /* Try to reap a child */
73 return waitpid(-1, &status, WNOHANG);
74}
75
76/* Don't use the glibc version, which caches the result in TLS. It misses some
77 * syscalls, and also breaks with clone(), which does not unshare the TLS.
78 */
79
80int os_getpid(void)
81{
82 return syscall(__NR_getpid);
83}
84
85int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
86 int r, int w, int x)
87{
88 void *loc;
89 int prot;
90
91 prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
92 (x ? PROT_EXEC : 0);
93
94 loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
95 fd, off);
96 if (loc == MAP_FAILED)
97 return -errno;
98 return 0;
99}
100
101int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
102{
103 int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
104 (x ? PROT_EXEC : 0));
105
106 if (mprotect(addr, len, prot) < 0)
107 return -errno;
108
109 return 0;
110}
111
112int os_unmap_memory(void *addr, int len)
113{
114 int err;
115
116 err = munmap(addr, len);
117 if (err < 0)
118 return -errno;
119 return 0;
120}
121
122#ifndef MADV_REMOVE
123#define MADV_REMOVE KERNEL_MADV_REMOVE
124#endif
125
126int os_drop_memory(void *addr, int length)
127{
128 int err;
129
130 err = madvise(addr, length, MADV_REMOVE);
131 if (err < 0)
132 err = -errno;
133 return err;
134}
135
136int __init can_drop_memory(void)
137{
138 void *addr;
139 int fd, ok = 0;
140
141 printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
142 fd = create_mem_file(UM_KERN_PAGE_SIZE);
143 if (fd < 0) {
144 printk(UM_KERN_ERR "Creating test memory file failed, "
145 "err = %d\n", -fd);
146 goto out;
147 }
148
149 addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
150 MAP_SHARED, fd, 0);
151 if (addr == MAP_FAILED) {
152 printk(UM_KERN_ERR "Mapping test memory file failed, "
153 "err = %d\n", -errno);
154 goto out_close;
155 }
156
157 if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
158 printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
159 goto out_unmap;
160 }
161
162 printk(UM_KERN_CONT "OK\n");
163 ok = 1;
164
165out_unmap:
166 munmap(addr, UM_KERN_PAGE_SIZE);
167out_close:
168 close(fd);
169out:
170 return ok;
171}
172
173void init_new_thread_signals(void)
174{
175 set_handler(SIGSEGV);
176 set_handler(SIGTRAP);
177 set_handler(SIGFPE);
178 set_handler(SIGILL);
179 set_handler(SIGBUS);
180 signal(SIGHUP, SIG_IGN);
181 set_handler(SIGIO);
182 /* We (currently) only use the child reaper IRQ in seccomp mode */
183 if (using_seccomp)
184 set_handler(SIGCHLD);
185 signal(SIGWINCH, SIG_IGN);
186}
187
188void os_set_pdeathsig(void)
189{
190 prctl(PR_SET_PDEATHSIG, SIGKILL);
191}