arch/um/os-Linux/process.c

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