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 "user_util.h"
  18 #include "process.h"
  19 #include "irq_user.h"
  20 #include "kern_util.h"
  21 #include "longjmp.h"
  22 #include "skas_ptrace.h"
  23 #include "kern_constants.h"
  24
  25 #define ARBITRARY_ADDR -1
  26 #define FAILURE_PID    -1
  27
  28 #define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
  29 #define COMM_SCANF "%*[^)])"
  30
  31 unsigned long os_process_pc(int pid)
  32 {
  33         char proc_stat[STAT_PATH_LEN], buf[256];
  34         unsigned long pc;
  35         int fd, err;
  36
  37         sprintf(proc_stat, "/proc/%d/stat", pid);
  38         fd = os_open_file(proc_stat, of_read(OPENFLAGS()), 0);
  39         if(fd < 0){
  40                 printk("os_process_pc - couldn't open '%s', err = %d\n",
  41                        proc_stat, -fd);
  42                 return(ARBITRARY_ADDR);
  43         }
  44         err = os_read_file(fd, buf, sizeof(buf));
  45         if(err < 0){
  46                 printk("os_process_pc - couldn't read '%s', err = %d\n",
  47                        proc_stat, -err);
  48                 os_close_file(fd);
  49                 return(ARBITRARY_ADDR);
  50         }
  51         os_close_file(fd);
  52         pc = ARBITRARY_ADDR;
  53         if(sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
  54                   "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
  55                   "%*d %*d %*d %*d %*d %lu", &pc) != 1){
  56                 printk("os_process_pc - couldn't find pc in '%s'\n", buf);
  57         }
  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, n, fd;
  66
  67         if(pid == -1) return(-1);
  68
  69         snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
  70         fd = os_open_file(stat, of_read(OPENFLAGS()), 0);
  71         if(fd < 0){
  72                 printk("Couldn't open '%s', err = %d\n", stat, -fd);
  73                 return(FAILURE_PID);
  74         }
  75
  76         n = os_read_file(fd, data, sizeof(data));
  77         os_close_file(fd);
  78
  79         if(n < 0){
  80                 printk("Couldn't read '%s', err = %d\n", stat, -n);
  81                 return(FAILURE_PID);
  82         }
  83
  84         parent = FAILURE_PID;
  85         n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
  86         if(n != 1)
  87                 printk("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, 0));
 102
 103 }
 104
 105 /* This is here uniquely to have access to the userspace errno, i.e. the one
 106  * used by ptrace in case of error.
 107  */
 108
 109 long os_ptrace_ldt(long pid, long addr, long data)
 110 {
 111         int ret;
 112
 113         ret = ptrace(PTRACE_LDT, pid, addr, data);
 114
 115         if (ret < 0)
 116                 return -errno;
 117         return ret;
 118 }
 119
 120 /* Kill off a ptraced child by all means available.  kill it normally first,
 121  * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
 122  * which it can't exit directly.
 123  */
 124
 125 void os_kill_ptraced_process(int pid, int reap_child)
 126 {
 127         kill(pid, SIGKILL);
 128         ptrace(PTRACE_KILL, pid);
 129         ptrace(PTRACE_CONT, pid);
 130         if(reap_child)
 131                 CATCH_EINTR(waitpid(pid, NULL, 0));
 132 }
 133
 134 void os_usr1_process(int pid)
 135 {
 136         kill(pid, SIGUSR1);
 137 }
 138
 139 /* Don't use the glibc version, which caches the result in TLS. It misses some
 140  * syscalls, and also breaks with clone(), which does not unshare the TLS.
 141  */
 142
 143 int os_getpid(void)
 144 {
 145         return(syscall(__NR_getpid));
 146 }
 147
 148 int os_getpgrp(void)
 149 {
 150         return getpgrp();
 151 }
 152
 153 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
 154                   int r, int w, int x)
 155 {
 156         void *loc;
 157         int prot;
 158
 159         prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 160                 (x ? PROT_EXEC : 0);
 161
 162         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
 163                      fd, off);
 164         if(loc == MAP_FAILED)
 165                 return(-errno);
 166         return(0);
 167 }
 168
 169 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
 170 {
 171         int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 172                     (x ? PROT_EXEC : 0));
 173
 174         if(mprotect(addr, len, prot) < 0)
 175                 return(-errno);
 176         return(0);
 177 }
 178
 179 int os_unmap_memory(void *addr, int len)
 180 {
 181         int err;
 182
 183         err = munmap(addr, len);
 184         if(err < 0)
 185                 return(-errno);
 186         return(0);
 187 }
 188
 189 #ifndef MADV_REMOVE
 190 #define MADV_REMOVE KERNEL_MADV_REMOVE
 191 #endif
 192
 193 int os_drop_memory(void *addr, int length)
 194 {
 195         int err;
 196
 197         err = madvise(addr, length, MADV_REMOVE);
 198         if(err < 0)
 199                 err = -errno;
 200         return err;
 201 }
 202
 203 int can_drop_memory(void)
 204 {
 205         void *addr;
 206         int fd, ok = 0;
 207
 208         printk("Checking host MADV_REMOVE support...");
 209         fd = create_mem_file(UM_KERN_PAGE_SIZE);
 210         if(fd < 0){
 211                 printk("Creating test memory file failed, err = %d\n", -fd);
 212                 goto out;
 213         }
 214
 215         addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 216                       MAP_SHARED, fd, 0);
 217         if(addr == MAP_FAILED){
 218                 printk("Mapping test memory file failed, err = %d\n", -errno);
 219                 goto out_close;
 220         }
 221
 222         if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){
 223                 printk("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_stack(void *sig_stack, void (*usr1_handler)(int))
 239 {
 240         int flags = 0, pages;
 241
 242         if(sig_stack != NULL){
 243                 pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
 244                 set_sigstack(sig_stack, pages * page_size());
 245                 flags = SA_ONSTACK;
 246         }
 247         if(usr1_handler){
 248                 struct sigaction sa;
 249
 250                 sa.sa_handler = usr1_handler;
 251                 sigemptyset(&sa.sa_mask);
 252                 sa.sa_flags = flags;
 253                 sa.sa_restorer = NULL;
 254                 if(sigaction(SIGUSR1, &sa, NULL) < 0)
 255                         panic("init_new_thread_stack - sigaction failed - "
 256                               "errno = %d\n", errno);
 257         }
 258 }
 259
 260 void init_new_thread_signals(void)
 261 {
 262         set_handler(SIGSEGV, (__sighandler_t) sig_handler, SA_ONSTACK,
 263                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 264         set_handler(SIGTRAP, (__sighandler_t) sig_handler, SA_ONSTACK,
 265                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 266         set_handler(SIGFPE, (__sighandler_t) sig_handler, SA_ONSTACK,
 267                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 268         set_handler(SIGILL, (__sighandler_t) sig_handler, SA_ONSTACK,
 269                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 270         set_handler(SIGBUS, (__sighandler_t) sig_handler, SA_ONSTACK,
 271                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 272         set_handler(SIGUSR2, (__sighandler_t) sig_handler,
 273                     SA_ONSTACK, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
 274                     -1);
 275         signal(SIGHUP, SIG_IGN);
 276
 277         init_irq_signals(1);
 278 }
 279
 280 int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
 281 {
 282         jmp_buf buf;
 283         int n;
 284
 285         *jmp_ptr = &buf;
 286         n = UML_SETJMP(&buf);
 287         if(n != 0)
 288                 return n;
 289         (*fn)(arg);
 290         return 0;
 291 }