Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
4 : * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 : */
6 :
7 : #include <stdio.h>
8 : #include <stdlib.h>
9 : #include <unistd.h>
10 : #include <errno.h>
11 : #include <signal.h>
12 : #include <string.h>
13 : #include <sys/resource.h>
14 : #include <as-layout.h>
15 : #include <init.h>
16 : #include <kern_util.h>
17 : #include <os.h>
18 : #include <um_malloc.h>
19 :
20 : #define PGD_BOUND (4 * 1024 * 1024)
21 : #define STACKSIZE (8 * 1024 * 1024)
22 : #define THREAD_NAME_LEN (256)
23 :
24 : long elf_aux_hwcap;
25 :
26 5 : static void set_stklim(void)
27 : {
28 : struct rlimit lim;
29 :
30 5 : if (getrlimit(RLIMIT_STACK, &lim) < 0) {
31 0 : perror("getrlimit");
32 0 : exit(1);
33 : }
34 5 : if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) {
35 0 : lim.rlim_cur = STACKSIZE;
36 0 : if (setrlimit(RLIMIT_STACK, &lim) < 0) {
37 0 : perror("setrlimit");
38 0 : exit(1);
39 : }
40 : }
41 5 : }
42 :
43 0 : static void last_ditch_exit(int sig)
44 : {
45 0 : uml_cleanup();
46 0 : exit(1);
47 : }
48 :
49 10 : static void install_fatal_handler(int sig)
50 : {
51 : struct sigaction action;
52 :
53 : /* All signals are enabled in this handler ... */
54 10 : sigemptyset(&action.sa_mask);
55 :
56 : /*
57 : * ... including the signal being handled, plus we want the
58 : * handler reset to the default behavior, so that if an exit
59 : * handler is hanging for some reason, the UML will just die
60 : * after this signal is sent a second time.
61 : */
62 10 : action.sa_flags = SA_RESETHAND | SA_NODEFER;
63 10 : action.sa_restorer = NULL;
64 10 : action.sa_handler = last_ditch_exit;
65 10 : if (sigaction(sig, &action, NULL) < 0) {
66 0 : os_warn("failed to install handler for signal %d "
67 0 : "- errno = %d\n", sig, errno);
68 0 : exit(1);
69 : }
70 10 : }
71 :
72 : #define UML_LIB_PATH ":" OS_LIB_PATH "/uml"
73 :
74 5 : static void setup_env_path(void)
75 : {
76 5 : char *new_path = NULL;
77 5 : char *old_path = NULL;
78 5 : int path_len = 0;
79 :
80 5 : old_path = getenv("PATH");
81 : /*
82 : * if no PATH variable is set or it has an empty value
83 : * just use the default + /usr/lib/uml
84 : */
85 5 : if (!old_path || (path_len = strlen(old_path)) == 0) {
86 0 : if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH))
87 0 : perror("couldn't putenv");
88 : return;
89 : }
90 :
91 : /* append /usr/lib/uml to the existing path */
92 5 : path_len += strlen("PATH=" UML_LIB_PATH) + 1;
93 5 : new_path = malloc(path_len);
94 5 : if (!new_path) {
95 0 : perror("couldn't malloc to set a new PATH");
96 0 : return;
97 : }
98 5 : snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
99 5 : if (putenv(new_path)) {
100 0 : perror("couldn't putenv to set a new PATH");
101 0 : free(new_path);
102 : }
103 : }
104 :
105 : extern void scan_elf_aux( char **envp);
106 :
107 5 : int __init main(int argc, char **argv, char **envp)
108 : {
109 : char **new_argv;
110 : int ret, i, err;
111 :
112 5 : set_stklim();
113 :
114 5 : setup_env_path();
115 :
116 5 : setsid();
117 :
118 5 : new_argv = malloc((argc + 1) * sizeof(char *));
119 5 : if (new_argv == NULL) {
120 0 : perror("Mallocing argv");
121 0 : exit(1);
122 : }
123 25 : for (i = 0; i < argc; i++) {
124 25 : new_argv[i] = strdup(argv[i]);
125 25 : if (new_argv[i] == NULL) {
126 0 : perror("Mallocing an arg");
127 0 : exit(1);
128 : }
129 : }
130 5 : new_argv[argc] = NULL;
131 :
132 : /*
133 : * Allow these signals to bring down a UML if all other
134 : * methods of control fail.
135 : */
136 5 : install_fatal_handler(SIGINT);
137 5 : install_fatal_handler(SIGTERM);
138 :
139 : #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
140 : scan_elf_aux(envp);
141 : #endif
142 :
143 5 : change_sig(SIGPIPE, 0);
144 5 : ret = linux_main(argc, argv);
145 :
146 : /*
147 : * Disable SIGPROF - I have no idea why libc doesn't do this or turn
148 : * off the profiling time, but UML dies with a SIGPROF just before
149 : * exiting when profiling is active.
150 : */
151 1 : change_sig(SIGPROF, 0);
152 :
153 : /*
154 : * This signal stuff used to be in the reboot case. However,
155 : * sometimes a timer signal can come in when we're halting (reproducably
156 : * when writing out gcov information, presumably because that takes
157 : * some time) and cause a segfault.
158 : */
159 :
160 : /* stop timers and set timer signal to be ignored */
161 1 : os_timer_disable();
162 :
163 : /* disable SIGIO for the fds and set SIGIO to be ignored */
164 1 : err = deactivate_all_fds();
165 1 : if (err)
166 0 : os_warn("deactivate_all_fds failed, errno = %d\n", -err);
167 :
168 : /*
169 : * Let any pending signals fire now. This ensures
170 : * that they won't be delivered after the exec, when
171 : * they are definitely not expected.
172 : */
173 1 : unblock_signals();
174 :
175 1 : os_info("\n");
176 : /* Reboot */
177 1 : if (ret) {
178 0 : execvp(new_argv[0], new_argv);
179 0 : perror("Failed to exec kernel");
180 0 : ret = 1;
181 : }
182 1 : return uml_exitcode;
183 : }
184 :
185 : extern void *__real_malloc(int);
186 :
187 19 : void *__wrap_malloc(int size)
188 : {
189 : void *ret;
190 :
191 19 : if (!kmalloc_ok)
192 17 : return __real_malloc(size);
193 2 : else if (size <= UM_KERN_PAGE_SIZE)
194 : /* finding contiguous pages can be hard*/
195 2 : ret = uml_kmalloc(size, UM_GFP_KERNEL);
196 0 : else ret = vmalloc(size);
197 :
198 : /*
199 : * glibc people insist that if malloc fails, errno should be
200 : * set by malloc as well. So we do.
201 : */
202 2 : if (ret == NULL)
203 0 : errno = ENOMEM;
204 :
205 : return ret;
206 : }
207 :
208 0 : void *__wrap_calloc(int n, int size)
209 : {
210 0 : void *ptr = __wrap_malloc(n * size);
211 :
212 0 : if (ptr == NULL)
213 : return NULL;
214 0 : memset(ptr, 0, n * size);
215 0 : return ptr;
216 : }
217 :
218 : extern void __real_free(void *);
219 :
220 : extern unsigned long high_physmem;
221 :
222 24 : void __wrap_free(void *ptr)
223 : {
224 24 : unsigned long addr = (unsigned long) ptr;
225 :
226 : /*
227 : * We need to know how the allocation happened, so it can be correctly
228 : * freed. This is done by seeing what region of memory the pointer is
229 : * in -
230 : * physical memory - kmalloc/kfree
231 : * kernel virtual memory - vmalloc/vfree
232 : * anywhere else - malloc/free
233 : * If kmalloc is not yet possible, then either high_physmem and/or
234 : * end_vm are still 0 (as at startup), in which case we call free, or
235 : * we have set them, but anyway addr has not been allocated from those
236 : * areas. So, in both cases __real_free is called.
237 : *
238 : * CAN_KMALLOC is checked because it would be bad to free a buffer
239 : * with kmalloc/vmalloc after they have been turned off during
240 : * shutdown.
241 : * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
242 : * there is a possibility for memory leaks.
243 : */
244 :
245 24 : if ((addr >= uml_physmem) && (addr < high_physmem)) {
246 2 : if (kmalloc_ok)
247 1 : kfree(ptr);
248 : }
249 22 : else if ((addr >= start_vm) && (addr < end_vm)) {
250 0 : if (kmalloc_ok)
251 0 : vfree(ptr);
252 : }
253 22 : else __real_free(ptr);
254 24 : }
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