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 <linux/unistd.h>
  11 #include <sys/mman.h>
  12 #include <sys/wait.h>
  13 #include <sys/mman.h>
  14 #include <sys/syscall.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 int os_getpid(void)
 145 {
 146         return(syscall(__NR_getpid));
 147 }
 148
 149 int os_getpgrp(void)
 150 {
 151         return getpgrp();
 152 }
 153
 154 int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
 155                   int r, int w, int x)
 156 {
 157         void *loc;
 158         int prot;
 159
 160         prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 161                 (x ? PROT_EXEC : 0);
 162
 163         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
 164                      fd, off);
 165         if(loc == MAP_FAILED)
 166                 return(-errno);
 167         return(0);
 168 }
 169
 170 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
 171 {
 172         int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
 173                     (x ? PROT_EXEC : 0));
 174
 175         if(mprotect(addr, len, prot) < 0)
 176                 return(-errno);
 177         return(0);
 178 }
 179
 180 int os_unmap_memory(void *addr, int len)
 181 {
 182         int err;
 183
 184         err = munmap(addr, len);
 185         if(err < 0)
 186                 return(-errno);
 187         return(0);
 188 }
 189
 190 #ifndef MADV_REMOVE
 191 #define MADV_REMOVE KERNEL_MADV_REMOVE
 192 #endif
 193
 194 int os_drop_memory(void *addr, int length)
 195 {
 196         int err;
 197
 198         err = madvise(addr, length, MADV_REMOVE);
 199         if(err < 0)
 200                 err = -errno;
 201         return err;
 202 }
 203
 204 int can_drop_memory(void)
 205 {
 206         void *addr;
 207         int fd, ok = 0;
 208
 209         printk("Checking host MADV_REMOVE support...");
 210         fd = create_mem_file(UM_KERN_PAGE_SIZE);
 211         if(fd < 0){
 212                 printk("Creating test memory file failed, err = %d\n", -fd);
 213                 goto out;
 214         }
 215
 216         addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 217                       MAP_SHARED, fd, 0);
 218         if(addr == MAP_FAILED){
 219                 printk("Mapping test memory file failed, err = %d\n", -errno);
 220                 goto out_close;
 221         }
 222
 223         if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){
 224                 printk("MADV_REMOVE failed, err = %d\n", -errno);
 225                 goto out_unmap;
 226         }
 227
 228         printk("OK\n");
 229         ok = 1;
 230
 231 out_unmap:
 232         munmap(addr, UM_KERN_PAGE_SIZE);
 233 out_close:
 234         close(fd);
 235 out:
 236         return ok;
 237 }
 238
 239 void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
 240 {
 241         int flags = 0, pages;
 242
 243         if(sig_stack != NULL){
 244                 pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
 245                 set_sigstack(sig_stack, pages * page_size());
 246                 flags = SA_ONSTACK;
 247         }
 248         if(usr1_handler){
 249                 struct sigaction sa;
 250
 251                 sa.sa_handler = usr1_handler;
 252                 sigemptyset(&sa.sa_mask);
 253                 sa.sa_flags = flags;
 254                 sa.sa_restorer = NULL;
 255                 if(sigaction(SIGUSR1, &sa, NULL) < 0)
 256                         panic("init_new_thread_stack - sigaction failed - "
 257                               "errno = %d\n", errno);
 258         }
 259 }
 260
 261 void init_new_thread_signals(void)
 262 {
 263         set_handler(SIGSEGV, (__sighandler_t) sig_handler, SA_ONSTACK,
 264                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 265         set_handler(SIGTRAP, (__sighandler_t) sig_handler, SA_ONSTACK,
 266                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 267         set_handler(SIGFPE, (__sighandler_t) sig_handler, SA_ONSTACK,
 268                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 269         set_handler(SIGILL, (__sighandler_t) sig_handler, SA_ONSTACK,
 270                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 271         set_handler(SIGBUS, (__sighandler_t) sig_handler, SA_ONSTACK,
 272                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 273         set_handler(SIGUSR2, (__sighandler_t) sig_handler,
 274                     SA_ONSTACK, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
 275                     -1);
 276         signal(SIGHUP, SIG_IGN);
 277
 278         init_irq_signals(1);
 279 }
 280
 281 int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
 282 {
 283         jmp_buf buf;
 284         int n;
 285
 286         *jmp_ptr = &buf;
 287         n = UML_SETJMP(&buf);
 288         if(n != 0)
 289                 return n;
 290         (*fn)(arg);
 291         return 0;
 292 }