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util.c

/*
 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <sys/param.h>
#include <sys/time.h>
#include "asm/types.h"
#include <ctype.h>
#include <signal.h>
#include <wait.h>
#include <errno.h>
#include <stdarg.h>
#include <sched.h>
#include <termios.h>
#include <string.h>
#include "kern_util.h"
#include "user.h"
#include "mem_user.h"
#include "init.h"
#include "ptrace_user.h"
#include "uml-config.h"
#include "os.h"
#include "longjmp.h"
#include "kern_constants.h"

void stack_protections(unsigned long address)
{
      if(mprotect((void *) address, UM_THREAD_SIZE,
                PROT_READ | PROT_WRITE | PROT_EXEC) < 0)
            panic("protecting stack failed, errno = %d", errno);
}

int raw(int fd)
{
      struct termios tt;
      int err;

      CATCH_EINTR(err = tcgetattr(fd, &tt));
      if(err < 0)
            return -errno;

      cfmakeraw(&tt);

      CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt));
      if(err < 0)
            return -errno;

      /* XXX tcsetattr could have applied only some changes
       * (and cfmakeraw() is a set of changes) */
      return 0;
}

void setup_machinename(char *machine_out)
{
      struct utsname host;

      uname(&host);
#ifdef UML_CONFIG_UML_X86
# ifndef UML_CONFIG_64BIT
      if (!strcmp(host.machine, "x86_64")) {
            strcpy(machine_out, "i686");
            return;
      }
# else
      if (!strcmp(host.machine, "i686")) {
            strcpy(machine_out, "x86_64");
            return;
      }
# endif
#endif
      strcpy(machine_out, host.machine);
}

void setup_hostinfo(char *buf, int len)
{
      struct utsname host;

      uname(&host);
      snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename,
             host.release, host.version, host.machine);
}

int setjmp_wrapper(void (*proc)(void *, void *), ...)
{
      va_list args;
      jmp_buf buf;
      int n;

      n = UML_SETJMP(&buf);
      if(n == 0){
            va_start(args, proc);
            (*proc)(&buf, &args);
      }
      va_end(args);
      return n;
}

void os_dump_core(void)
{
      int pid;

      signal(SIGSEGV, SIG_DFL);

      /*
       * We are about to SIGTERM this entire process group to ensure that
       * nothing is around to run after the kernel exits.  The
       * kernel wants to abort, not die through SIGTERM, so we
       * ignore it here.
       */

      signal(SIGTERM, SIG_IGN);
      kill(0, SIGTERM);
      /*
       * Most of the other processes associated with this UML are
       * likely sTopped, so give them a SIGCONT so they see the
       * SIGTERM.
       */
      kill(0, SIGCONT);

      /*
       * Now, having sent signals to everyone but us, make sure they
       * die by ptrace.  Processes can survive what's been done to
       * them so far - the mechanism I understand is receiving a
       * SIGSEGV and segfaulting immediately upon return.  There is
       * always a SIGSEGV pending, and (I'm guessing) signals are
       * processed in numeric order so the SIGTERM (signal 15 vs
       * SIGSEGV being signal 11) is never handled.
       *
       * Run a waitpid loop until we get some kind of error.
       * Hopefully, it's ECHILD, but there's not a lot we can do if
       * it's something else.  Tell os_kill_ptraced_process not to
       * wait for the child to report its death because there's
       * nothing reasonable to do if that fails.
       */

      while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
            os_kill_ptraced_process(pid, 0);

      abort();
}

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