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 "kern_constants.h"
  17 #include "longjmp.h"
  18 #include "os.h"
  19 #include "process.h"
  20 #include "skas_ptrace.h"
  21 #include "user.h"
  22
  23 #define ARBITRARY_ADDR -1
  24 #define FAILURE_PID    -1
  25
  26 #define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
  27 #define COMM_SCANF "%*[^)])"
  28
  29 unsigned long os_process_pc(int pid)
  30 {
  31         char proc_stat[STAT_PATH_LEN], buf[256];
  32         unsigned long pc = ARBITRARY_ADDR;
  33         int fd, err;
  34
  35         sprintf(proc_stat, "/proc/%d/stat", pid);
  36         fd = open(proc_stat, O_RDONLY, 0);
  37         if (fd < 0) {
  38                 printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', "
  39                        "errno = %d\n", proc_stat, errno);
  40                 goto out;
  41         }
  42         CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
  43         if (err < 0) {
  44                 printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', "
  45                        "err = %d\n", proc_stat, errno);
  46                 goto out_close;
  47         }
  48         os_close_file(fd);
  49         pc = ARBITRARY_ADDR;
  50         if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
  51                    "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
  52                    "%*d %*d %*d %*d %*d %lu", &pc) != 1)
  53                 printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n",
  54                        buf);
  55  out_close:
  56         close(fd);
  57  out:
  58         return pc;
  59 }
  60
  61 int os_process_parent(int pid)
  62 {
  63         char stat[STAT_PATH_LEN];
  64         char data[256];
  65         int parent = FAILURE_PID, n, fd;
  66
  67         if (pid == -1)
  68                 return parent;
  69
  70         snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
  71         fd = open(stat, O_RDONLY, 0);
  72         if (fd < 0) {
  73                 printk(UM_KERN_ERR "Couldn't open '%s', errno = %d\n", stat,
  74                        errno);
  75                 return parent;
  76         }
  77
  78         CATCH_EINTR(n = read(fd, data, sizeof(data)));
  79         close(fd);
  80
  81         if (n < 0) {
  82                 printk(UM_KERN_ERR "Couldn't read '%s', errno = %d\n", stat,
  83                        errno);
  84                 return parent;
  85         }
  86
  87         parent = FAILURE_PID;
  88         n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
  89         if (n != 1)
  90                 printk(UM_KERN_ERR "Failed to scan '%s'\n", data);
  91
  92         return parent;
  93 }
  94
  95 void os_stop_process(int pid)
  96 {
  97         kill(pid, SIGSTOP);
  98 }
  99
 100 void os_kill_process(int pid, int reap_child)
 101 {
 102         kill(pid, SIGKILL);
 103         if (reap_child)
 104                 CATCH_EINTR(waitpid(pid, NULL, __WALL));
 105 }
 106
 107 /* This is here uniquely to have access to the userspace errno, i.e. the one
 108  * used by ptrace in case of error.
 109  */
 110
 111 long os_ptrace_ldt(long pid, long addr, long data)
 112 {
 113         int ret;
 114
 115         ret = ptrace(PTRACE_LDT, pid, addr, data);
 116
 117         if (ret < 0)
 118                 return -errno;
 119         return ret;
 120 }
 121
 122 /* Kill off a ptraced child by all means available.  kill it normally first,
 123  * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
 124  * which it can't exit directly.
 125  */
 126
 127 void os_kill_ptraced_process(int pid, int reap_child)
 128 {
 129         kill(pid, SIGKILL);
 130         ptrace(PTRACE_KILL, pid);
 131         ptrace(PTRACE_CONT, pid);
 132         if (reap_child)
 133                 CATCH_EINTR(waitpid(pid, NULL, __WALL));
 134 }
 135
 136 /* Don't use the glibc version, which caches the result in TLS. It misses some
 137  * syscalls, and also breaks with clone(), which does not unshare the TLS.
 138  */
 139
 140 int os_getpid(void)
 141 {
 142         return syscall(__NR_getpid);
 143 }
 144
 145 int os_getpgrp(void)
 146 {
 147         return getpgrp();
 148 }
 149
 150 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
 151                   int r, int w, int x)
 152 {
 153         void *loc;
 154         int prot;
 155
 156         prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 157                 (x ? PROT_EXEC : 0);
 158
 159         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
 160                      fd, off);
 161         if (loc == MAP_FAILED)
 162                 return -errno;
 163         return 0;
 164 }
 165
 166 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
 167 {
 168         int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 169                     (x ? PROT_EXEC : 0));
 170
 171         if (mprotect(addr, len, prot) < 0)
 172                 return -errno;
 173
 174         return 0;
 175 }
 176
 177 int os_unmap_memory(void *addr, int len)
 178 {
 179         int err;
 180
 181         err = munmap(addr, len);
 182         if (err < 0)
 183                 return -errno;
 184         return 0;
 185 }
 186
 187 #ifndef MADV_REMOVE
 188 #define MADV_REMOVE KERNEL_MADV_REMOVE
 189 #endif
 190
 191 int os_drop_memory(void *addr, int length)
 192 {
 193         int err;
 194
 195         err = madvise(addr, length, MADV_REMOVE);
 196         if (err < 0)
 197                 err = -errno;
 198         return err;
 199 }
 200
 201 int __init can_drop_memory(void)
 202 {
 203         void *addr;
 204         int fd, ok = 0;
 205
 206         printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
 207         fd = create_mem_file(UM_KERN_PAGE_SIZE);
 208         if (fd < 0) {
 209                 printk(UM_KERN_ERR "Creating test memory file failed, "
 210                        "err = %d\n", -fd);
 211                 goto out;
 212         }
 213
 214         addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 215                       MAP_SHARED, fd, 0);
 216         if (addr == MAP_FAILED) {
 217                 printk(UM_KERN_ERR "Mapping test memory file failed, "
 218                        "err = %d\n", -errno);
 219                 goto out_close;
 220         }
 221
 222         if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
 223                 printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
 224                 goto out_unmap;
 225         }
 226
 227         printk("OK\n");
 228         ok = 1;
 229
 230 out_unmap:
 231         munmap(addr, UM_KERN_PAGE_SIZE);
 232 out_close:
 233         close(fd);
 234 out:
 235         return ok;
 236 }
 237
 238 void init_new_thread_signals(void)
 239 {
 240         set_handler(SIGSEGV, (__sighandler_t) sig_handler, SA_ONSTACK,
 241                     SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
 242         set_handler(SIGTRAP, (__sighandler_t) sig_handler, SA_ONSTACK,
 243                     SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
 244         set_handler(SIGFPE, (__sighandler_t) sig_handler, SA_ONSTACK,
 245                     SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
 246         set_handler(SIGILL, (__sighandler_t) sig_handler, SA_ONSTACK,
 247                     SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
 248         set_handler(SIGBUS, (__sighandler_t) sig_handler, SA_ONSTACK,
 249                     SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
 250         signal(SIGHUP, SIG_IGN);
 251
 252         set_handler(SIGIO, (__sighandler_t) sig_handler,
 253                     SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGALRM,
 254                     SIGVTALRM, -1);
 255         signal(SIGWINCH, SIG_IGN);
 256 }
 257
 258 int run_kernel_thread(int (*fn)(void *), void *arg, jmp_buf **jmp_ptr)
 259 {
 260         jmp_buf buf;
 261         int n;
 262
 263         *jmp_ptr = &buf;
 264         n = UML_SETJMP(&buf);
 265         if (n != 0)
 266                 return n;
 267         (*fn)(arg);
 268         return 0;
 269 }