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 <setjmp.h>
  11 #include <linux/unistd.h>
  12 #include <sys/mman.h>
  13 #include <sys/wait.h>
  14 #include <sys/mman.h>
  15 #include "ptrace_user.h"
  16 #include "os.h"
  17 #include "user.h"
  18 #include "user_util.h"
  19 #include "process.h"
  20 #include "irq_user.h"
  21 #include "kern_util.h"
  22 #include "longjmp.h"
  23 #include "skas_ptrace.h"
  24 #include "kern_constants.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         err = os_read_file(fd, buf, sizeof(buf));
  46         if(err < 0){
  47                 printk("os_process_pc - couldn't read '%s', err = %d\n",
  48                        proc_stat, -err);
  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) return(-1);
  69
  70         snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
  71         fd = os_open_file(stat, of_read(OPENFLAGS()), 0);
  72         if(fd < 0){
  73                 printk("Couldn't open '%s', err = %d\n", stat, -fd);
  74                 return(FAILURE_PID);
  75         }
  76
  77         n = os_read_file(fd, data, sizeof(data));
  78         os_close_file(fd);
  79
  80         if(n < 0){
  81                 printk("Couldn't read '%s', err = %d\n", stat, -n);
  82                 return(FAILURE_PID);
  83         }
  84
  85         parent = FAILURE_PID;
  86         n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
  87         if(n != 1)
  88                 printk("Failed to scan '%s'\n", data);
  89
  90         return(parent);
  91 }
  92
  93 void os_stop_process(int pid)
  94 {
  95         kill(pid, SIGSTOP);
  96 }
  97
  98 void os_kill_process(int pid, int reap_child)
  99 {
 100         kill(pid, SIGKILL);
 101         if(reap_child)
 102                 CATCH_EINTR(waitpid(pid, NULL, 0));
 103
 104 }
 105
 106 /* This is here uniquely to have access to the userspace errno, i.e. the one
 107  * used by ptrace in case of error.
 108  */
 109
 110 long os_ptrace_ldt(long pid, long addr, long data)
 111 {
 112         int ret;
 113
 114         ret = ptrace(PTRACE_LDT, pid, addr, data);
 115
 116         if (ret < 0)
 117                 return -errno;
 118         return ret;
 119 }
 120
 121 /* Kill off a ptraced child by all means available.  kill it normally first,
 122  * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
 123  * which it can't exit directly.
 124  */
 125
 126 void os_kill_ptraced_process(int pid, int reap_child)
 127 {
 128         kill(pid, SIGKILL);
 129         ptrace(PTRACE_KILL, pid);
 130         ptrace(PTRACE_CONT, pid);
 131         if(reap_child)
 132                 CATCH_EINTR(waitpid(pid, NULL, 0));
 133 }
 134
 135 void os_usr1_process(int pid)
 136 {
 137         kill(pid, SIGUSR1);
 138 }
 139
 140 /* Don't use the glibc version, which caches the result in TLS. It misses some
 141  * syscalls, and also breaks with clone(), which does not unshare the TLS.
 142  */
 143
 144 inline _syscall0(pid_t, getpid)
 145
 146 int os_getpid(void)
 147 {
 148         return(getpid());
 149 }
 150
 151 int os_getpgrp(void)
 152 {
 153         return getpgrp();
 154 }
 155
 156 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
 157                   int r, int w, int x)
 158 {
 159         void *loc;
 160         int prot;
 161
 162         prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 163                 (x ? PROT_EXEC : 0);
 164
 165         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
 166                      fd, off);
 167         if(loc == MAP_FAILED)
 168                 return(-errno);
 169         return(0);
 170 }
 171
 172 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
 173 {
 174         int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 175                     (x ? PROT_EXEC : 0));
 176
 177         if(mprotect(addr, len, prot) < 0)
 178                 return(-errno);
 179         return(0);
 180 }
 181
 182 int os_unmap_memory(void *addr, int len)
 183 {
 184         int err;
 185
 186         err = munmap(addr, len);
 187         if(err < 0)
 188                 return(-errno);
 189         return(0);
 190 }
 191
 192 #ifndef MADV_REMOVE
 193 #define MADV_REMOVE KERNEL_MADV_REMOVE
 194 #endif
 195
 196 int os_drop_memory(void *addr, int length)
 197 {
 198         int err;
 199
 200         err = madvise(addr, length, MADV_REMOVE);
 201         if(err < 0)
 202                 err = -errno;
 203         return err;
 204 }
 205
 206 int can_drop_memory(void)
 207 {
 208         void *addr;
 209         int fd, ok = 0;
 210
 211         printk("Checking host MADV_REMOVE support...");
 212         fd = create_mem_file(UM_KERN_PAGE_SIZE);
 213         if(fd < 0){
 214                 printk("Creating test memory file failed, err = %d\n", -fd);
 215                 goto out;
 216         }
 217
 218         addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 219                       MAP_SHARED, fd, 0);
 220         if(addr == MAP_FAILED){
 221                 printk("Mapping test memory file failed, err = %d\n", -errno);
 222                 goto out_close;
 223         }
 224
 225         if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){
 226                 printk("MADV_REMOVE failed, err = %d\n", -errno);
 227                 goto out_unmap;
 228         }
 229
 230         printk("OK\n");
 231         ok = 1;
 232
 233 out_unmap:
 234         munmap(addr, UM_KERN_PAGE_SIZE);
 235 out_close:
 236         close(fd);
 237 out:
 238         return ok;
 239 }
 240
 241 void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
 242 {
 243         int flags = 0, pages;
 244
 245         if(sig_stack != NULL){
 246                 pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
 247                 set_sigstack(sig_stack, pages * page_size());
 248                 flags = SA_ONSTACK;
 249         }
 250         if(usr1_handler) set_handler(SIGUSR1, usr1_handler, flags, -1);
 251 }
 252
 253 void init_new_thread_signals(int altstack)
 254 {
 255         int flags = altstack ? SA_ONSTACK : 0;
 256
 257         set_handler(SIGSEGV, (__sighandler_t) sig_handler, flags,
 258                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 259         set_handler(SIGTRAP, (__sighandler_t) sig_handler, flags,
 260                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 261         set_handler(SIGFPE, (__sighandler_t) sig_handler, flags,
 262                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 263         set_handler(SIGILL, (__sighandler_t) sig_handler, flags,
 264                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 265         set_handler(SIGBUS, (__sighandler_t) sig_handler, flags,
 266                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 267         set_handler(SIGUSR2, (__sighandler_t) sig_handler,
 268                     flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 269         signal(SIGHUP, SIG_IGN);
 270
 271         init_irq_signals(altstack);
 272 }
 273
 274 int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
 275 {
 276         jmp_buf buf;
 277         int n, enable;
 278
 279         *jmp_ptr = &buf;
 280         n = UML_SETJMP(&buf, enable);
 281         if(n != 0)
 282                 return(n);
 283         (*fn)(arg);
 284         return(0);
 285 }