1/*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <stdio.h>
7#include <stdlib.h>
8#include <unistd.h>
9#include <errno.h>
10#include <signal.h>
11#include <string.h>
12#include <sys/resource.h>
13#include <as-layout.h>
14#include <init.h>
15#include <kern_util.h>
16#include <os.h>
17#include <um_malloc.h>
18
19#define PGD_BOUND (4 * 1024 * 1024)
20#define STACKSIZE (8 * 1024 * 1024)
21#define THREAD_NAME_LEN (256)
22
23long elf_aux_hwcap;
24
25static void set_stklim(void)
26{
27	struct rlimit lim;
28
29	if (getrlimit(RLIMIT_STACK, &lim) < 0) {
30		perror("getrlimit");
31		exit(1);
32	}
33	if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) {
34		lim.rlim_cur = STACKSIZE;
35		if (setrlimit(RLIMIT_STACK, &lim) < 0) {
36			perror("setrlimit");
37			exit(1);
38		}
39	}
40}
41
42static __init void do_uml_initcalls(void)
43{
44	initcall_t *call;
45
46	call = &__uml_initcall_start;
47	while (call < &__uml_initcall_end) {
48		(*call)();
49		call++;
50	}
51}
52
53static void last_ditch_exit(int sig)
54{
55	uml_cleanup();
56	exit(1);
57}
58
59static void install_fatal_handler(int sig)
60{
61	struct sigaction action;
62
63	/* All signals are enabled in this handler ... */
64	sigemptyset(&action.sa_mask);
65
66	/*
67	 * ... including the signal being handled, plus we want the
68	 * handler reset to the default behavior, so that if an exit
69	 * handler is hanging for some reason, the UML will just die
70	 * after this signal is sent a second time.
71	 */
72	action.sa_flags = SA_RESETHAND | SA_NODEFER;
73	action.sa_restorer = NULL;
74	action.sa_handler = last_ditch_exit;
75	if (sigaction(sig, &action, NULL) < 0) {
76		printf("failed to install handler for signal %d - errno = %d\n",
77		       sig, errno);
78		exit(1);
79	}
80}
81
82#define UML_LIB_PATH	":" OS_LIB_PATH "/uml"
83
84static void setup_env_path(void)
85{
86	char *new_path = NULL;
87	char *old_path = NULL;
88	int path_len = 0;
89
90	old_path = getenv("PATH");
91	/*
92	 * if no PATH variable is set or it has an empty value
93	 * just use the default + /usr/lib/uml
94	 */
95	if (!old_path || (path_len = strlen(old_path)) == 0) {
96		if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH))
97			perror("couldn't putenv");
98		return;
99	}
100
101	/* append /usr/lib/uml to the existing path */
102	path_len += strlen("PATH=" UML_LIB_PATH) + 1;
103	new_path = malloc(path_len);
104	if (!new_path) {
105		perror("couldn't malloc to set a new PATH");
106		return;
107	}
108	snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
109	if (putenv(new_path)) {
110		perror("couldn't putenv to set a new PATH");
111		free(new_path);
112	}
113}
114
115extern void scan_elf_aux( char **envp);
116
117int __init main(int argc, char **argv, char **envp)
118{
119	char **new_argv;
120	int ret, i, err;
121
122	set_stklim();
123
124	setup_env_path();
125
126	setsid();
127
128	new_argv = malloc((argc + 1) * sizeof(char *));
129	if (new_argv == NULL) {
130		perror("Mallocing argv");
131		exit(1);
132	}
133	for (i = 0; i < argc; i++) {
134		new_argv[i] = strdup(argv[i]);
135		if (new_argv[i] == NULL) {
136			perror("Mallocing an arg");
137			exit(1);
138		}
139	}
140	new_argv[argc] = NULL;
141
142	/*
143	 * Allow these signals to bring down a UML if all other
144	 * methods of control fail.
145	 */
146	install_fatal_handler(SIGINT);
147	install_fatal_handler(SIGTERM);
148
149#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
150	scan_elf_aux(envp);
151#endif
152
153	do_uml_initcalls();
154	change_sig(SIGPIPE, 0);
155	ret = linux_main(argc, argv);
156
157	/*
158	 * Disable SIGPROF - I have no idea why libc doesn't do this or turn
159	 * off the profiling time, but UML dies with a SIGPROF just before
160	 * exiting when profiling is active.
161	 */
162	change_sig(SIGPROF, 0);
163
164	/*
165	 * This signal stuff used to be in the reboot case.  However,
166	 * sometimes a SIGVTALRM can come in when we're halting (reproducably
167	 * when writing out gcov information, presumably because that takes
168	 * some time) and cause a segfault.
169	 */
170
171	/* stop timers and set SIGVTALRM to be ignored */
172	disable_timer();
173
174	/* disable SIGIO for the fds and set SIGIO to be ignored */
175	err = deactivate_all_fds();
176	if (err)
177		printf("deactivate_all_fds failed, errno = %d\n", -err);
178
179	/*
180	 * Let any pending signals fire now.  This ensures
181	 * that they won't be delivered after the exec, when
182	 * they are definitely not expected.
183	 */
184	unblock_signals();
185
186	/* Reboot */
187	if (ret) {
188		printf("\n");
189		execvp(new_argv[0], new_argv);
190		perror("Failed to exec kernel");
191		ret = 1;
192	}
193	printf("\n");
194	return uml_exitcode;
195}
196
197extern void *__real_malloc(int);
198
199void *__wrap_malloc(int size)
200{
201	void *ret;
202
203	if (!kmalloc_ok)
204		return __real_malloc(size);
205	else if (size <= UM_KERN_PAGE_SIZE)
206		/* finding contiguous pages can be hard*/
207		ret = uml_kmalloc(size, UM_GFP_KERNEL);
208	else ret = vmalloc(size);
209
210	/*
211	 * glibc people insist that if malloc fails, errno should be
212	 * set by malloc as well. So we do.
213	 */
214	if (ret == NULL)
215		errno = ENOMEM;
216
217	return ret;
218}
219
220void *__wrap_calloc(int n, int size)
221{
222	void *ptr = __wrap_malloc(n * size);
223
224	if (ptr == NULL)
225		return NULL;
226	memset(ptr, 0, n * size);
227	return ptr;
228}
229
230extern void __real_free(void *);
231
232extern unsigned long high_physmem;
233
234void __wrap_free(void *ptr)
235{
236	unsigned long addr = (unsigned long) ptr;
237
238	/*
239	 * We need to know how the allocation happened, so it can be correctly
240	 * freed.  This is done by seeing what region of memory the pointer is
241	 * in -
242	 * 	physical memory - kmalloc/kfree
243	 *	kernel virtual memory - vmalloc/vfree
244	 * 	anywhere else - malloc/free
245	 * If kmalloc is not yet possible, then either high_physmem and/or
246	 * end_vm are still 0 (as at startup), in which case we call free, or
247	 * we have set them, but anyway addr has not been allocated from those
248	 * areas. So, in both cases __real_free is called.
249	 *
250	 * CAN_KMALLOC is checked because it would be bad to free a buffer
251	 * with kmalloc/vmalloc after they have been turned off during
252	 * shutdown.
253	 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
254	 * there is a possibility for memory leaks.
255	 */
256
257	if ((addr >= uml_physmem) && (addr < high_physmem)) {
258		if (kmalloc_ok)
259			kfree(ptr);
260	}
261	else if ((addr >= start_vm) && (addr < end_vm)) {
262		if (kmalloc_ok)
263			vfree(ptr);
264	}
265	else __real_free(ptr);
266}
267