/*
   * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   * Licensed under the GPL
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <errno.h>
  #include <signal.h>
  #include <string.h>
  #include <sys/resource.h>
  #include <as-layout.h>
  #include <init.h>
  #include <kern_util.h>
  #include <os.h>
  #include <um_malloc.h>
  
  #define PGD_BOUND (4 * 1024 * 1024)
  #define STACKSIZE (8 * 1024 * 1024)
  #define THREAD_NAME_LEN (256)
  
  long elf_aux_hwcap;
  
  static void set_stklim(void)
  {
  	struct rlimit lim;
  
  	if (getrlimit(RLIMIT_STACK, &lim) < 0) {
  		perror("getrlimit");
  		exit(1);
  	}
  	if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) {
  		lim.rlim_cur = STACKSIZE;
  		if (setrlimit(RLIMIT_STACK, &lim) < 0) {
  			perror("setrlimit");
  			exit(1);
  		}
  	}
  }
  
  static __init void do_uml_initcalls(void)
  {
  	initcall_t *call;
  
  	call = &__uml_initcall_start;
  	while (call < &__uml_initcall_end) {
  		(*call)();
  		call++;
  	}
  }
  
  static void last_ditch_exit(int sig)
  {
  	uml_cleanup();
  	exit(1);
  }
  
  static void install_fatal_handler(int sig)
  {
  	struct sigaction action;
  
  	/* All signals are enabled in this handler ... */
  	sigemptyset(&action.sa_mask);
  
  	/*
  	 * ... including the signal being handled, plus we want the
  	 * handler reset to the default behavior, so that if an exit
  	 * handler is hanging for some reason, the UML will just die
  	 * after this signal is sent a second time.
  	 */
  	action.sa_flags = SA_RESETHAND | SA_NODEFER;
  	action.sa_restorer = NULL;
  	action.sa_handler = last_ditch_exit;
  	if (sigaction(sig, &action, NULL) < 0) {
  		printf("failed to install handler for signal %d - errno = %d
  ",
  		       sig, errno);
  		exit(1);
  	}
  }
  
  #define UML_LIB_PATH	":" OS_LIB_PATH "/uml"
  
  static void setup_env_path(void)
  {
  	char *new_path = NULL;
  	char *old_path = NULL;
  	int path_len = 0;
  
  	old_path = getenv("PATH");
  	/*
  	 * if no PATH variable is set or it has an empty value
  	 * just use the default + /usr/lib/uml
  	 */
  	if (!old_path || (path_len = strlen(old_path)) == 0) {
  		if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH))
  			perror("couldn't putenv");
  		return;
  	}
  
  	/* append /usr/lib/uml to the existing path */
  	path_len += strlen("PATH=" UML_LIB_PATH) + 1;
  	new_path = malloc(path_len);
  	if (!new_path) {
  		perror("couldn't malloc to set a new PATH");
  		return;
  	}
  	snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
  	if (putenv(new_path)) {
  		perror("couldn't putenv to set a new PATH");
  		free(new_path);
  	}
  }
  
  extern void scan_elf_aux( char **envp);
  
  int __init main(int argc, char **argv, char **envp)
  {
  	char **new_argv;
  	int ret, i, err;
  
  	set_stklim();
  
  	setup_env_path();
  
  	setsid();
  
  	new_argv = malloc((argc + 1) * sizeof(char *));
  	if (new_argv == NULL) {
  		perror("Mallocing argv");
  		exit(1);
  	}
  	for (i = 0; i < argc; i++) {
  		new_argv[i] = strdup(argv[i]);
  		if (new_argv[i] == NULL) {
  			perror("Mallocing an arg");
  			exit(1);
  		}
  	}
  	new_argv[argc] = NULL;
  
  	/*
  	 * Allow these signals to bring down a UML if all other
  	 * methods of control fail.
  	 */
  	install_fatal_handler(SIGINT);
  	install_fatal_handler(SIGTERM);
  
  #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
  	scan_elf_aux(envp);
  #endif
  
  	do_uml_initcalls();
  	ret = linux_main(argc, argv);
  
  	/*
  	 * Disable SIGPROF - I have no idea why libc doesn't do this or turn
  	 * off the profiling time, but UML dies with a SIGPROF just before
  	 * exiting when profiling is active.
  	 */
  	change_sig(SIGPROF, 0);
  
  	/*
  	 * This signal stuff used to be in the reboot case.  However,
  	 * sometimes a SIGVTALRM can come in when we're halting (reproducably
  	 * when writing out gcov information, presumably because that takes
  	 * some time) and cause a segfault.
  	 */
  
  	/* stop timers and set SIGVTALRM to be ignored */
  	disable_timer();
  
  	/* disable SIGIO for the fds and set SIGIO to be ignored */
  	err = deactivate_all_fds();
  	if (err)
  		printf("deactivate_all_fds failed, errno = %d
  ", -err);
  
  	/*
  	 * Let any pending signals fire now.  This ensures
  	 * that they won't be delivered after the exec, when
  	 * they are definitely not expected.
  	 */
  	unblock_signals();
  
  	/* Reboot */
  	if (ret) {
  		printf("
  ");
  		execvp(new_argv[0], new_argv);
  		perror("Failed to exec kernel");
  		ret = 1;
  	}
  	printf("
  ");
  	return uml_exitcode;
  }
  
  extern void *__real_malloc(int);
  
  void *__wrap_malloc(int size)
  {
  	void *ret;
  
  	if (!kmalloc_ok)
  		return __real_malloc(size);
  	else if (size <= UM_KERN_PAGE_SIZE)
  		/* finding contiguous pages can be hard*/
  		ret = uml_kmalloc(size, UM_GFP_KERNEL);
  	else ret = vmalloc(size);
  
  	/*
  	 * glibc people insist that if malloc fails, errno should be
  	 * set by malloc as well. So we do.
  	 */
  	if (ret == NULL)
  		errno = ENOMEM;
  
  	return ret;
  }
  
  void *__wrap_calloc(int n, int size)
  {
  	void *ptr = __wrap_malloc(n * size);
  
  	if (ptr == NULL)
  		return NULL;
  	memset(ptr, 0, n * size);
  	return ptr;
  }
  
  extern void __real_free(void *);
  
  extern unsigned long high_physmem;
  
  void __wrap_free(void *ptr)
  {
  	unsigned long addr = (unsigned long) ptr;
  
  	/*
  	 * We need to know how the allocation happened, so it can be correctly
  	 * freed.  This is done by seeing what region of memory the pointer is
  	 * in -
  	 * 	physical memory - kmalloc/kfree
  	 *	kernel virtual memory - vmalloc/vfree
  	 * 	anywhere else - malloc/free
  	 * If kmalloc is not yet possible, then either high_physmem and/or
  	 * end_vm are still 0 (as at startup), in which case we call free, or
  	 * we have set them, but anyway addr has not been allocated from those
  	 * areas. So, in both cases __real_free is called.
  	 *
  	 * CAN_KMALLOC is checked because it would be bad to free a buffer
  	 * with kmalloc/vmalloc after they have been turned off during
  	 * shutdown.
  	 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
  	 * there is a possibility for memory leaks.
  	 */
  
  	if ((addr >= uml_physmem) && (addr < high_physmem)) {
  		if (kmalloc_ok)
  			kfree(ptr);
  	}
  	else if ((addr >= start_vm) && (addr < end_vm)) {
  		if (kmalloc_ok)
  			vfree(ptr);
  	}
  	else __real_free(ptr);
  }