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 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 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 93 void os_alarm_process(int pid) 94 { 95 kill(pid, SIGALRM); 96 } 97 98 void os_stop_process(int pid) 99 { 100 kill(pid, SIGSTOP); 101 } 102 103 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 */ 114 115 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 */ 127 128 int os_getpid(void) 129 { 130 return syscall(__NR_getpid); 131 } 132 133 int os_getpgrp(void) 134 { 135 return getpgrp(); 136 } 137 138 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 } 153 154 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 } 164 165 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 178 179 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 } 188 189 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 } 225 226 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 } 241 242 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 } 276 277 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