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 <unistd.h>
   8 #include <errno.h>
   9 #include <signal.h>
  10 #include <fcntl.h>
  11 #include <sys/mman.h>
  12 #include <sys/ptrace.h>
  13 #include <sys/wait.h>
  14 #include <asm/unistd.h>
  15 #include "init.h"
  16 #include "longjmp.h"
  17 #include "os.h"
  18 #include "skas_ptrace.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 /* This is here uniquely to have access to the userspace errno, i.e. the one
 105  * used by ptrace in case of error.
 106  */
 107
 108 long os_ptrace_ldt(long pid, long addr, long data)
 109 {
 110         int ret;
 111
 112         ret = ptrace(PTRACE_LDT, pid, addr, data);
 113
 114         if (ret < 0)
 115                 return -errno;
 116         return ret;
 117 }
 118
 119 /* Kill off a ptraced child by all means available.  kill it normally first,
 120  * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
 121  * which it can't exit directly.
 122  */
 123
 124 void os_kill_ptraced_process(int pid, int reap_child)
 125 {
 126         kill(pid, SIGKILL);
 127         ptrace(PTRACE_KILL, pid);
 128         ptrace(PTRACE_CONT, pid);
 129         if (reap_child)
 130                 CATCH_EINTR(waitpid(pid, NULL, __WALL));
 131 }
 132
 133 /* Don't use the glibc version, which caches the result in TLS. It misses some
 134  * syscalls, and also breaks with clone(), which does not unshare the TLS.
 135  */
 136
 137 int os_getpid(void)
 138 {
 139         return syscall(__NR_getpid);
 140 }
 141
 142 int os_getpgrp(void)
 143 {
 144         return getpgrp();
 145 }
 146
 147 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
 148                   int r, int w, int x)
 149 {
 150         void *loc;
 151         int prot;
 152
 153         prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 154                 (x ? PROT_EXEC : 0);
 155
 156         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
 157                      fd, off);
 158         if (loc == MAP_FAILED)
 159                 return -errno;
 160         return 0;
 161 }
 162
 163 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
 164 {
 165         int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 166                     (x ? PROT_EXEC : 0));
 167
 168         if (mprotect(addr, len, prot) < 0)
 169                 return -errno;
 170
 171         return 0;
 172 }
 173
 174 int os_unmap_memory(void *addr, int len)
 175 {
 176         int err;
 177
 178         err = munmap(addr, len);
 179         if (err < 0)
 180                 return -errno;
 181         return 0;
 182 }
 183
 184 #ifndef MADV_REMOVE
 185 #define MADV_REMOVE KERNEL_MADV_REMOVE
 186 #endif
 187
 188 int os_drop_memory(void *addr, int length)
 189 {
 190         int err;
 191
 192         err = madvise(addr, length, MADV_REMOVE);
 193         if (err < 0)
 194                 err = -errno;
 195         return err;
 196 }
 197
 198 int __init can_drop_memory(void)
 199 {
 200         void *addr;
 201         int fd, ok = 0;
 202
 203         printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
 204         fd = create_mem_file(UM_KERN_PAGE_SIZE);
 205         if (fd < 0) {
 206                 printk(UM_KERN_ERR "Creating test memory file failed, "
 207                        "err = %d\n", -fd);
 208                 goto out;
 209         }
 210
 211         addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 212                       MAP_SHARED, fd, 0);
 213         if (addr == MAP_FAILED) {
 214                 printk(UM_KERN_ERR "Mapping test memory file failed, "
 215                        "err = %d\n", -errno);
 216                 goto out_close;
 217         }
 218
 219         if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
 220                 printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
 221                 goto out_unmap;
 222         }
 223
 224         printk(UM_KERN_CONT "OK\n");
 225         ok = 1;
 226
 227 out_unmap:
 228         munmap(addr, UM_KERN_PAGE_SIZE);
 229 out_close:
 230         close(fd);
 231 out:
 232         return ok;
 233 }
 234
 235 void init_new_thread_signals(void)
 236 {
 237         set_handler(SIGSEGV);
 238         set_handler(SIGTRAP);
 239         set_handler(SIGFPE);
 240         set_handler(SIGILL);
 241         set_handler(SIGBUS);
 242         signal(SIGHUP, SIG_IGN);
 243         set_handler(SIGIO);
 244         signal(SIGWINCH, SIG_IGN);
 245         signal(SIGTERM, SIG_DFL);
 246 }
 247
 248 int run_kernel_thread(int (*fn)(void *), void *arg, jmp_buf **jmp_ptr)
 249 {
 250         jmp_buf buf;
 251         int n;
 252
 253         *jmp_ptr = &buf;
 254         n = UML_SETJMP(&buf);
 255         if (n != 0)
 256                 return n;
 257         (*fn)(arg);
 258         return 0;
 259 }