main.c 5.9 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
/*
 * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include <sys/resource.h>
#include <sys/mman.h>
#include <sys/user.h>
#include "kern_util.h"
J
Jeff Dike 已提交
16
#include "as-layout.h"
L
Linus Torvalds 已提交
17 18 19 20 21 22 23 24
#include "mem_user.h"
#include "irq_user.h"
#include "user.h"
#include "init.h"
#include "mode.h"
#include "choose-mode.h"
#include "uml-config.h"
#include "os.h"
25
#include "um_malloc.h"
J
Jeff Dike 已提交
26
#include "kern_constants.h"
L
Linus Torvalds 已提交
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

#define PGD_BOUND (4 * 1024 * 1024)
#define STACKSIZE (8 * 1024 * 1024)
#define THREAD_NAME_LEN (256)

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;
54
	while (call < &__uml_initcall_end){
L
Linus Torvalds 已提交
55 56 57 58 59 60 61 62 63 64 65
		(*call)();
		call++;
	}
}

static void last_ditch_exit(int sig)
{
	uml_cleanup();
	exit(1);
}

66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87
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\n",
		       errno);
		exit(1);
	}
}

88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115
#define UML_LIB_PATH	":/usr/lib/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) {
		putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH);
		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("coudn't malloc to set a new PATH");
		return;
	}
	snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
	putenv(new_path);
}

L
Linus Torvalds 已提交
116 117 118 119
extern int uml_exitcode;

extern void scan_elf_aux( char **envp);

J
Jeff Dike 已提交
120
int __init main(int argc, char **argv, char **envp)
L
Linus Torvalds 已提交
121 122
{
	char **new_argv;
123
	int ret, i, err;
L
Linus Torvalds 已提交
124 125 126

	set_stklim();

127 128
	setup_env_path();

L
Linus Torvalds 已提交
129 130 131 132 133 134 135 136 137 138 139 140 141 142
	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;

143 144 145 146 147 148
	/* Allow these signals to bring down a UML if all other
	 * methods of control fail.
	 */
	install_fatal_handler(SIGINT);
	install_fatal_handler(SIGTERM);
	install_fatal_handler(SIGHUP);
L
Linus Torvalds 已提交
149 150 151 152 153 154 155 156 157 158 159 160

	scan_elf_aux( envp);

	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);

161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179
	/* 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 SIG*ALRM 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\n", -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();
L
Linus Torvalds 已提交
180

181 182 183
	/* Reboot */
	if(ret){
		printf("\n");
L
Linus Torvalds 已提交
184 185 186 187 188
		execvp(new_argv[0], new_argv);
		perror("Failed to exec kernel");
		ret = 1;
	}
	printf("\n");
J
Jeff Dike 已提交
189
	return uml_exitcode;
L
Linus Torvalds 已提交
190 191 192 193 194 195 196 197 198 199 200 201
}

#define CAN_KMALLOC() \
	(kmalloc_ok && CHOOSE_MODE((os_getpid() != tracing_pid), 1))

extern void *__real_malloc(int);

void *__wrap_malloc(int size)
{
	void *ret;

	if(!CAN_KMALLOC())
J
Jeff Dike 已提交
202
		return __real_malloc(size);
J
Jeff Dike 已提交
203 204
	else if(size <= UM_KERN_PAGE_SIZE)
		/* finding contiguous pages can be hard*/
205 206
		ret = kmalloc(size, UM_GFP_KERNEL);
	else ret = vmalloc(size);
L
Linus Torvalds 已提交
207 208 209 210 211 212 213

	/* glibc people insist that if malloc fails, errno should be
	 * set by malloc as well. So we do.
	 */
	if(ret == NULL)
		errno = ENOMEM;

J
Jeff Dike 已提交
214
	return ret;
L
Linus Torvalds 已提交
215 216 217 218 219 220
}

void *__wrap_calloc(int n, int size)
{
	void *ptr = __wrap_malloc(n * size);

J
Jeff Dike 已提交
221 222
	if(ptr == NULL)
		return NULL;
L
Linus Torvalds 已提交
223
	memset(ptr, 0, n * size);
J
Jeff Dike 已提交
224
	return ptr;
L
Linus Torvalds 已提交
225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
}

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(CAN_KMALLOC())
			kfree(ptr);
	}
	else if((addr >= start_vm) && (addr < end_vm)){
		if(CAN_KMALLOC())
			vfree(ptr);
	}
	else __real_free(ptr);
}