xref: /linux/arch/um/os-Linux/main.c (revision 6aa802ce6acc9b1f0b34114b3f7c21c84872cc3a)
152c653b3SJeff Dike /*
252c653b3SJeff Dike  * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
352c653b3SJeff Dike  * Licensed under the GPL
452c653b3SJeff Dike  */
552c653b3SJeff Dike 
652c653b3SJeff Dike #include <unistd.h>
752c653b3SJeff Dike #include <stdio.h>
852c653b3SJeff Dike #include <stdlib.h>
952c653b3SJeff Dike #include <string.h>
1052c653b3SJeff Dike #include <signal.h>
1152c653b3SJeff Dike #include <errno.h>
1252c653b3SJeff Dike #include <sys/resource.h>
1352c653b3SJeff Dike #include <sys/mman.h>
1452c653b3SJeff Dike #include <sys/user.h>
1552c653b3SJeff Dike #include "kern_util.h"
164ff83ce1SJeff Dike #include "as-layout.h"
1752c653b3SJeff Dike #include "mem_user.h"
1852c653b3SJeff Dike #include "irq_user.h"
1952c653b3SJeff Dike #include "user.h"
2052c653b3SJeff Dike #include "init.h"
2152c653b3SJeff Dike #include "mode.h"
2252c653b3SJeff Dike #include "uml-config.h"
2352c653b3SJeff Dike #include "os.h"
24c13e5690SPaolo 'Blaisorblade' Giarrusso #include "um_malloc.h"
25c539ab73SJeff Dike #include "kern_constants.h"
2652c653b3SJeff Dike 
2752c653b3SJeff Dike #define PGD_BOUND (4 * 1024 * 1024)
2852c653b3SJeff Dike #define STACKSIZE (8 * 1024 * 1024)
2952c653b3SJeff Dike #define THREAD_NAME_LEN (256)
3052c653b3SJeff Dike 
3152c653b3SJeff Dike static void set_stklim(void)
3252c653b3SJeff Dike {
3352c653b3SJeff Dike 	struct rlimit lim;
3452c653b3SJeff Dike 
3552c653b3SJeff Dike 	if(getrlimit(RLIMIT_STACK, &lim) < 0){
3652c653b3SJeff Dike 		perror("getrlimit");
3752c653b3SJeff Dike 		exit(1);
3852c653b3SJeff Dike 	}
3952c653b3SJeff Dike 	if((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)){
4052c653b3SJeff Dike 		lim.rlim_cur = STACKSIZE;
4152c653b3SJeff Dike 		if(setrlimit(RLIMIT_STACK, &lim) < 0){
4252c653b3SJeff Dike 			perror("setrlimit");
4352c653b3SJeff Dike 			exit(1);
4452c653b3SJeff Dike 		}
4552c653b3SJeff Dike 	}
4652c653b3SJeff Dike }
4752c653b3SJeff Dike 
4852c653b3SJeff Dike static __init void do_uml_initcalls(void)
4952c653b3SJeff Dike {
5052c653b3SJeff Dike 	initcall_t *call;
5152c653b3SJeff Dike 
5252c653b3SJeff Dike 	call = &__uml_initcall_start;
53f2183125SJeff Dike 	while (call < &__uml_initcall_end){
5452c653b3SJeff Dike 		(*call)();
5552c653b3SJeff Dike 		call++;
5652c653b3SJeff Dike 	}
5752c653b3SJeff Dike }
5852c653b3SJeff Dike 
5952c653b3SJeff Dike static void last_ditch_exit(int sig)
6052c653b3SJeff Dike {
6152c653b3SJeff Dike 	uml_cleanup();
6252c653b3SJeff Dike 	exit(1);
6352c653b3SJeff Dike }
6452c653b3SJeff Dike 
654b84c69bSJeff Dike static void install_fatal_handler(int sig)
664b84c69bSJeff Dike {
674b84c69bSJeff Dike 	struct sigaction action;
684b84c69bSJeff Dike 
694b84c69bSJeff Dike 	/* All signals are enabled in this handler ... */
704b84c69bSJeff Dike 	sigemptyset(&action.sa_mask);
714b84c69bSJeff Dike 
724b84c69bSJeff Dike 	/* ... including the signal being handled, plus we want the
734b84c69bSJeff Dike 	 * handler reset to the default behavior, so that if an exit
744b84c69bSJeff Dike 	 * handler is hanging for some reason, the UML will just die
754b84c69bSJeff Dike 	 * after this signal is sent a second time.
764b84c69bSJeff Dike 	 */
774b84c69bSJeff Dike 	action.sa_flags = SA_RESETHAND | SA_NODEFER;
784b84c69bSJeff Dike 	action.sa_restorer = NULL;
794b84c69bSJeff Dike 	action.sa_handler = last_ditch_exit;
804b84c69bSJeff Dike 	if(sigaction(sig, &action, NULL) < 0){
814b84c69bSJeff Dike 		printf("failed to install handler for signal %d - errno = %d\n",
824b84c69bSJeff Dike 		       errno);
834b84c69bSJeff Dike 		exit(1);
844b84c69bSJeff Dike 	}
854b84c69bSJeff Dike }
864b84c69bSJeff Dike 
87cb98cdcdSMattia Dongili #define UML_LIB_PATH	":/usr/lib/uml"
88cb98cdcdSMattia Dongili 
89cb98cdcdSMattia Dongili static void setup_env_path(void)
90cb98cdcdSMattia Dongili {
91cb98cdcdSMattia Dongili 	char *new_path = NULL;
92cb98cdcdSMattia Dongili 	char *old_path = NULL;
93cb98cdcdSMattia Dongili 	int path_len = 0;
94cb98cdcdSMattia Dongili 
95cb98cdcdSMattia Dongili 	old_path = getenv("PATH");
96cb98cdcdSMattia Dongili 	/* if no PATH variable is set or it has an empty value
97cb98cdcdSMattia Dongili 	 * just use the default + /usr/lib/uml
98cb98cdcdSMattia Dongili 	 */
99cb98cdcdSMattia Dongili 	if (!old_path || (path_len = strlen(old_path)) == 0) {
100cb98cdcdSMattia Dongili 		putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH);
101cb98cdcdSMattia Dongili 		return;
102cb98cdcdSMattia Dongili 	}
103cb98cdcdSMattia Dongili 
104cb98cdcdSMattia Dongili 	/* append /usr/lib/uml to the existing path */
105cb98cdcdSMattia Dongili 	path_len += strlen("PATH=" UML_LIB_PATH) + 1;
106cb98cdcdSMattia Dongili 	new_path = malloc(path_len);
107cb98cdcdSMattia Dongili 	if (!new_path) {
108cb98cdcdSMattia Dongili 		perror("coudn't malloc to set a new PATH");
109cb98cdcdSMattia Dongili 		return;
110cb98cdcdSMattia Dongili 	}
111cb98cdcdSMattia Dongili 	snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
112cb98cdcdSMattia Dongili 	putenv(new_path);
113cb98cdcdSMattia Dongili }
114cb98cdcdSMattia Dongili 
11552c653b3SJeff Dike extern int uml_exitcode;
11652c653b3SJeff Dike 
11752c653b3SJeff Dike extern void scan_elf_aux( char **envp);
11852c653b3SJeff Dike 
11936e45463SJeff Dike int __init main(int argc, char **argv, char **envp)
12052c653b3SJeff Dike {
12152c653b3SJeff Dike 	char **new_argv;
12252c653b3SJeff Dike 	int ret, i, err;
12352c653b3SJeff Dike 
12452c653b3SJeff Dike 	set_stklim();
12552c653b3SJeff Dike 
126cb98cdcdSMattia Dongili 	setup_env_path();
127cb98cdcdSMattia Dongili 
12852c653b3SJeff Dike 	new_argv = malloc((argc + 1) * sizeof(char *));
12952c653b3SJeff Dike 	if(new_argv == NULL){
13052c653b3SJeff Dike 		perror("Mallocing argv");
13152c653b3SJeff Dike 		exit(1);
13252c653b3SJeff Dike 	}
13352c653b3SJeff Dike 	for(i=0;i<argc;i++){
13452c653b3SJeff Dike 		new_argv[i] = strdup(argv[i]);
13552c653b3SJeff Dike 		if(new_argv[i] == NULL){
13652c653b3SJeff Dike 			perror("Mallocing an arg");
13752c653b3SJeff Dike 			exit(1);
13852c653b3SJeff Dike 		}
13952c653b3SJeff Dike 	}
14052c653b3SJeff Dike 	new_argv[argc] = NULL;
14152c653b3SJeff Dike 
1424b84c69bSJeff Dike 	/* Allow these signals to bring down a UML if all other
1434b84c69bSJeff Dike 	 * methods of control fail.
1444b84c69bSJeff Dike 	 */
1454b84c69bSJeff Dike 	install_fatal_handler(SIGINT);
1464b84c69bSJeff Dike 	install_fatal_handler(SIGTERM);
1474b84c69bSJeff Dike 	install_fatal_handler(SIGHUP);
14852c653b3SJeff Dike 
14952c653b3SJeff Dike 	scan_elf_aux( envp);
15052c653b3SJeff Dike 
15152c653b3SJeff Dike 	do_uml_initcalls();
15252c653b3SJeff Dike 	ret = linux_main(argc, argv);
15352c653b3SJeff Dike 
15452c653b3SJeff Dike 	/* Disable SIGPROF - I have no idea why libc doesn't do this or turn
15552c653b3SJeff Dike 	 * off the profiling time, but UML dies with a SIGPROF just before
15652c653b3SJeff Dike 	 * exiting when profiling is active.
15752c653b3SJeff Dike 	 */
15852c653b3SJeff Dike 	change_sig(SIGPROF, 0);
15952c653b3SJeff Dike 
16052c653b3SJeff Dike 	/* This signal stuff used to be in the reboot case.  However,
16152c653b3SJeff Dike 	 * sometimes a SIGVTALRM can come in when we're halting (reproducably
16252c653b3SJeff Dike 	 * when writing out gcov information, presumably because that takes
16352c653b3SJeff Dike 	 * some time) and cause a segfault.
16452c653b3SJeff Dike 	 */
16552c653b3SJeff Dike 
16652c653b3SJeff Dike 	/* stop timers and set SIG*ALRM to be ignored */
16752c653b3SJeff Dike 	disable_timer();
16852c653b3SJeff Dike 
16952c653b3SJeff Dike 	/* disable SIGIO for the fds and set SIGIO to be ignored */
17052c653b3SJeff Dike 	err = deactivate_all_fds();
17152c653b3SJeff Dike 	if(err)
17252c653b3SJeff Dike 		printf("deactivate_all_fds failed, errno = %d\n", -err);
17352c653b3SJeff Dike 
17452c653b3SJeff Dike 	/* Let any pending signals fire now.  This ensures
17552c653b3SJeff Dike 	 * that they won't be delivered after the exec, when
17652c653b3SJeff Dike 	 * they are definitely not expected.
17752c653b3SJeff Dike 	 */
17852c653b3SJeff Dike 	unblock_signals();
17952c653b3SJeff Dike 
18052c653b3SJeff Dike 	/* Reboot */
18152c653b3SJeff Dike 	if(ret){
18252c653b3SJeff Dike 		printf("\n");
18352c653b3SJeff Dike 		execvp(new_argv[0], new_argv);
18452c653b3SJeff Dike 		perror("Failed to exec kernel");
18552c653b3SJeff Dike 		ret = 1;
18652c653b3SJeff Dike 	}
18752c653b3SJeff Dike 	printf("\n");
188a5ed1ffaSJeff Dike 	return uml_exitcode;
18952c653b3SJeff Dike }
19052c653b3SJeff Dike 
19152c653b3SJeff Dike extern void *__real_malloc(int);
19252c653b3SJeff Dike 
19352c653b3SJeff Dike void *__wrap_malloc(int size)
19452c653b3SJeff Dike {
19552c653b3SJeff Dike 	void *ret;
19652c653b3SJeff Dike 
197*6aa802ceSJeff Dike 	if(!kmalloc_ok)
198a5ed1ffaSJeff Dike 		return __real_malloc(size);
199c539ab73SJeff Dike 	else if(size <= UM_KERN_PAGE_SIZE)
200c539ab73SJeff Dike 		/* finding contiguous pages can be hard*/
201e4c4bf99SJeff Dike 		ret = kmalloc(size, UM_GFP_KERNEL);
202e4c4bf99SJeff Dike 	else ret = vmalloc(size);
20352c653b3SJeff Dike 
20452c653b3SJeff Dike 	/* glibc people insist that if malloc fails, errno should be
20552c653b3SJeff Dike 	 * set by malloc as well. So we do.
20652c653b3SJeff Dike 	 */
20752c653b3SJeff Dike 	if(ret == NULL)
20852c653b3SJeff Dike 		errno = ENOMEM;
20952c653b3SJeff Dike 
210a5ed1ffaSJeff Dike 	return ret;
21152c653b3SJeff Dike }
21252c653b3SJeff Dike 
21352c653b3SJeff Dike void *__wrap_calloc(int n, int size)
21452c653b3SJeff Dike {
21552c653b3SJeff Dike 	void *ptr = __wrap_malloc(n * size);
21652c653b3SJeff Dike 
217a5ed1ffaSJeff Dike 	if(ptr == NULL)
218a5ed1ffaSJeff Dike 		return NULL;
21952c653b3SJeff Dike 	memset(ptr, 0, n * size);
220a5ed1ffaSJeff Dike 	return ptr;
22152c653b3SJeff Dike }
22252c653b3SJeff Dike 
22352c653b3SJeff Dike extern void __real_free(void *);
22452c653b3SJeff Dike 
22552c653b3SJeff Dike extern unsigned long high_physmem;
22652c653b3SJeff Dike 
22752c653b3SJeff Dike void __wrap_free(void *ptr)
22852c653b3SJeff Dike {
22952c653b3SJeff Dike 	unsigned long addr = (unsigned long) ptr;
23052c653b3SJeff Dike 
23152c653b3SJeff Dike 	/* We need to know how the allocation happened, so it can be correctly
23252c653b3SJeff Dike 	 * freed.  This is done by seeing what region of memory the pointer is
23352c653b3SJeff Dike 	 * in -
23452c653b3SJeff Dike 	 * 	physical memory - kmalloc/kfree
23552c653b3SJeff Dike 	 *	kernel virtual memory - vmalloc/vfree
23652c653b3SJeff Dike 	 * 	anywhere else - malloc/free
23752c653b3SJeff Dike 	 * If kmalloc is not yet possible, then either high_physmem and/or
23852c653b3SJeff Dike 	 * end_vm are still 0 (as at startup), in which case we call free, or
23952c653b3SJeff Dike 	 * we have set them, but anyway addr has not been allocated from those
24052c653b3SJeff Dike 	 * areas. So, in both cases __real_free is called.
24152c653b3SJeff Dike 	 *
24252c653b3SJeff Dike 	 * CAN_KMALLOC is checked because it would be bad to free a buffer
24352c653b3SJeff Dike 	 * with kmalloc/vmalloc after they have been turned off during
24452c653b3SJeff Dike 	 * shutdown.
24552c653b3SJeff Dike 	 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
24652c653b3SJeff Dike 	 * there is a possibility for memory leaks.
24752c653b3SJeff Dike 	 */
24852c653b3SJeff Dike 
24952c653b3SJeff Dike 	if((addr >= uml_physmem) && (addr < high_physmem)){
250*6aa802ceSJeff Dike 		if(kmalloc_ok)
25152c653b3SJeff Dike 			kfree(ptr);
25252c653b3SJeff Dike 	}
25352c653b3SJeff Dike 	else if((addr >= start_vm) && (addr < end_vm)){
254*6aa802ceSJeff Dike 		if(kmalloc_ok)
25552c653b3SJeff Dike 			vfree(ptr);
25652c653b3SJeff Dike 	}
25752c653b3SJeff Dike 	else __real_free(ptr);
25852c653b3SJeff Dike }
259