arch/um/os-Linux/process.c

   1 /*
   2  * Copyright (C) 2002 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <unistd.h>
   7 #include <stdio.h>
   8 #include <errno.h>
   9 #include <signal.h>
  10 #include <sys/mman.h>
  11 #include <sys/wait.h>
  12 #include <sys/mman.h>
  13 #include <sys/syscall.h>
  14 #include "ptrace_user.h"
  15 #include "os.h"
  16 #include "user.h"
  17 #include "process.h"
  18 #include "irq_user.h"
  19 #include "kern_util.h"
  20 #include "longjmp.h"
  21 #include "skas_ptrace.h"
  22 #include "kern_constants.h"
  23 #include "uml-config.h"
  24 #include "init.h"
  25
  26 #define ARBITRARY_ADDR -1
  27 #define FAILURE_PID    -1
  28
  29 #define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
  30 #define COMM_SCANF "%*[^)])"
  31
  32 unsigned long os_process_pc(int pid)
  33 {
  34         char proc_stat[STAT_PATH_LEN], buf[256];
  35         unsigned long pc;
  36         int fd, err;
  37
  38         sprintf(proc_stat, "/proc/%d/stat", pid);
  39         fd = os_open_file(proc_stat, of_read(OPENFLAGS()), 0);
  40         if(fd < 0){
  41                 printk("os_process_pc - couldn't open '%s', err = %d\n",
  42                        proc_stat, -fd);
  43                 return ARBITRARY_ADDR;
  44         }
  45         CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
  46         if(err < 0){
  47                 printk("os_process_pc - couldn't read '%s', err = %d\n",
  48                        proc_stat, errno);
  49                 os_close_file(fd);
  50                 return ARBITRARY_ADDR;
  51         }
  52         os_close_file(fd);
  53         pc = ARBITRARY_ADDR;
  54         if(sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
  55                   "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
  56                   "%*d %*d %*d %*d %*d %lu", &pc) != 1){
  57                 printk("os_process_pc - couldn't find pc in '%s'\n", buf);
  58         }
  59         return pc;
  60 }
  61
  62 int os_process_parent(int pid)
  63 {
  64         char stat[STAT_PATH_LEN];
  65         char data[256];
  66         int parent, n, fd;
  67
  68         if(pid == -1)
  69                 return -1;
  70
  71         snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
  72         fd = os_open_file(stat, of_read(OPENFLAGS()), 0);
  73         if(fd < 0){
  74                 printk("Couldn't open '%s', err = %d\n", stat, -fd);
  75                 return FAILURE_PID;
  76         }
  77
  78         CATCH_EINTR(n = read(fd, data, sizeof(data)));
  79         os_close_file(fd);
  80
  81         if(n < 0){
  82                 printk("Couldn't read '%s', err = %d\n", stat, errno);
  83                 return FAILURE_PID;
  84         }
  85
  86         parent = FAILURE_PID;
  87         n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
  88         if(n != 1)
  89                 printk("Failed to scan '%s'\n", data);
  90
  91         return parent;
  92 }
  93
  94 void os_stop_process(int pid)
  95 {
  96         kill(pid, SIGSTOP);
  97 }
  98
  99 void os_kill_process(int pid, int reap_child)
 100 {
 101         kill(pid, SIGKILL);
 102         if(reap_child)
 103                 CATCH_EINTR(waitpid(pid, NULL, 0));
 104
 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, 0));
 134 }
 135
 136 #ifdef UML_CONFIG_MODE_TT
 137 void os_usr1_process(int pid)
 138 {
 139         kill(pid, SIGUSR1);
 140 }
 141 #endif
 142
 143 /* Don't use the glibc version, which caches the result in TLS. It misses some
 144  * syscalls, and also breaks with clone(), which does not unshare the TLS.
 145  */
 146
 147 int os_getpid(void)
 148 {
 149         return syscall(__NR_getpid);
 150 }
 151
 152 int os_getpgrp(void)
 153 {
 154         return getpgrp();
 155 }
 156
 157 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
 158                   int r, int w, int x)
 159 {
 160         void *loc;
 161         int prot;
 162
 163         prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 164                 (x ? PROT_EXEC : 0);
 165
 166         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
 167                      fd, off);
 168         if(loc == MAP_FAILED)
 169                 return -errno;
 170         return 0;
 171 }
 172
 173 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
 174 {
 175         int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 176                     (x ? PROT_EXEC : 0));
 177
 178         if(mprotect(addr, len, prot) < 0)
 179                 return -errno;
 180         return 0;
 181 }
 182
 183 int os_unmap_memory(void *addr, int len)
 184 {
 185         int err;
 186
 187         err = munmap(addr, len);
 188         if(err < 0)
 189                 return -errno;
 190         return 0;
 191 }
 192
 193 #ifndef MADV_REMOVE
 194 #define MADV_REMOVE KERNEL_MADV_REMOVE
 195 #endif
 196
 197 int __init os_drop_memory(void *addr, int length)
 198 {
 199         int err;
 200
 201         err = madvise(addr, length, MADV_REMOVE);
 202         if(err < 0)
 203                 err = -errno;
 204         return err;
 205 }
 206
 207 int __init can_drop_memory(void)
 208 {
 209         void *addr;
 210         int fd, ok = 0;
 211
 212         printk("Checking host MADV_REMOVE support...");
 213         fd = create_mem_file(UM_KERN_PAGE_SIZE);
 214         if(fd < 0){
 215                 printk("Creating test memory file failed, err = %d\n", -fd);
 216                 goto out;
 217         }
 218
 219         addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 220                       MAP_SHARED, fd, 0);
 221         if(addr == MAP_FAILED){
 222                 printk("Mapping test memory file failed, err = %d\n", -errno);
 223                 goto out_close;
 224         }
 225
 226         if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){
 227                 printk("MADV_REMOVE failed, err = %d\n", -errno);
 228                 goto out_unmap;
 229         }
 230
 231         printk("OK\n");
 232         ok = 1;
 233
 234 out_unmap:
 235         munmap(addr, UM_KERN_PAGE_SIZE);
 236 out_close:
 237         close(fd);
 238 out:
 239         return ok;
 240 }
 241
 242 #ifdef UML_CONFIG_MODE_TT
 243 void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
 244 {
 245         int flags = 0, pages;
 246
 247         if(sig_stack != NULL){
 248                 pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
 249                 set_sigstack(sig_stack, pages * UM_KERN_PAGE_SIZE);
 250                 flags = SA_ONSTACK;
 251         }
 252         if(usr1_handler){
 253                 struct sigaction sa;
 254
 255                 sa.sa_handler = usr1_handler;
 256                 sigemptyset(&sa.sa_mask);
 257                 sa.sa_flags = flags;
 258                 sa.sa_restorer = NULL;
 259                 if(sigaction(SIGUSR1, &sa, NULL) < 0)
 260                         panic("init_new_thread_stack - sigaction failed - "
 261                               "errno = %d\n", errno);
 262         }
 263 }
 264 #endif
 265
 266 void init_new_thread_signals(void)
 267 {
 268         set_handler(SIGSEGV, (__sighandler_t) sig_handler, SA_ONSTACK,
 269                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 270         set_handler(SIGTRAP, (__sighandler_t) sig_handler, SA_ONSTACK,
 271                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 272         set_handler(SIGFPE, (__sighandler_t) sig_handler, SA_ONSTACK,
 273                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 274         set_handler(SIGILL, (__sighandler_t) sig_handler, SA_ONSTACK,
 275                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 276         set_handler(SIGBUS, (__sighandler_t) sig_handler, SA_ONSTACK,
 277                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 278         set_handler(SIGUSR2, (__sighandler_t) sig_handler,
 279                     SA_ONSTACK, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
 280                     -1);
 281         signal(SIGHUP, SIG_IGN);
 282
 283         init_irq_signals(1);
 284 }
 285
 286 int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
 287 {
 288         jmp_buf buf;
 289         int n;
 290
 291         *jmp_ptr = &buf;
 292         n = UML_SETJMP(&buf);
 293         if(n != 0)
 294                 return n;
 295         (*fn)(arg);
 296         return 0;
 297 }