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 | static void set_stklim(void) |
27 | { |
28 | struct rlimit lim; |
29 | |
30 | if (getrlimit(RLIMIT_STACK, &lim) < 0) { |
31 | perror("getrlimit" ); |
32 | exit(1); |
33 | } |
34 | if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) { |
35 | lim.rlim_cur = STACKSIZE; |
36 | if (setrlimit(RLIMIT_STACK, &lim) < 0) { |
37 | perror("setrlimit" ); |
38 | exit(1); |
39 | } |
40 | } |
41 | } |
42 | |
43 | static void last_ditch_exit(int sig) |
44 | { |
45 | uml_cleanup(); |
46 | exit(1); |
47 | } |
48 | |
49 | static void install_fatal_handler(int sig) |
50 | { |
51 | struct sigaction action; |
52 | |
53 | /* All signals are enabled in this handler ... */ |
54 | 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 | action.sa_flags = SA_RESETHAND | SA_NODEFER; |
63 | action.sa_restorer = NULL; |
64 | action.sa_handler = last_ditch_exit; |
65 | if (sigaction(sig, &action, NULL) < 0) { |
66 | os_warn("failed to install handler for signal %d " |
67 | "- errno = %d\n" , sig, errno); |
68 | exit(1); |
69 | } |
70 | } |
71 | |
72 | #define UML_LIB_PATH ":" OS_LIB_PATH "/uml" |
73 | |
74 | static void setup_env_path(void) |
75 | { |
76 | char *new_path = NULL; |
77 | char *old_path = NULL; |
78 | int path_len = 0; |
79 | |
80 | 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 | if (!old_path || (path_len = strlen(old_path)) == 0) { |
86 | if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH)) |
87 | perror("couldn't putenv" ); |
88 | return; |
89 | } |
90 | |
91 | /* append /usr/lib/uml to the existing path */ |
92 | path_len += strlen("PATH=" UML_LIB_PATH) + 1; |
93 | new_path = malloc(path_len); |
94 | if (!new_path) { |
95 | perror("couldn't malloc to set a new PATH" ); |
96 | return; |
97 | } |
98 | snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path); |
99 | if (putenv(new_path)) { |
100 | perror("couldn't putenv to set a new PATH" ); |
101 | free(new_path); |
102 | } |
103 | } |
104 | |
105 | extern void scan_elf_aux( char **envp); |
106 | |
107 | int __init main(int argc, char **argv, char **envp) |
108 | { |
109 | char **new_argv; |
110 | int ret, i, err; |
111 | |
112 | set_stklim(); |
113 | |
114 | setup_env_path(); |
115 | |
116 | setsid(); |
117 | |
118 | new_argv = malloc((argc + 1) * sizeof(char *)); |
119 | if (new_argv == NULL) { |
120 | perror("Mallocing argv" ); |
121 | exit(1); |
122 | } |
123 | for (i = 0; i < argc; i++) { |
124 | new_argv[i] = strdup(argv[i]); |
125 | if (new_argv[i] == NULL) { |
126 | perror("Mallocing an arg" ); |
127 | exit(1); |
128 | } |
129 | } |
130 | 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 | install_fatal_handler(SIGINT); |
137 | install_fatal_handler(SIGTERM); |
138 | |
139 | #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA |
140 | scan_elf_aux(envp); |
141 | #endif |
142 | |
143 | change_sig(SIGPIPE, 0); |
144 | 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 | 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 | os_timer_disable(); |
162 | |
163 | /* disable SIGIO for the fds and set SIGIO to be ignored */ |
164 | err = deactivate_all_fds(); |
165 | if (err) |
166 | 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 | unblock_signals(); |
174 | |
175 | os_info("\n" ); |
176 | /* Reboot */ |
177 | if (ret) { |
178 | execvp(new_argv[0], new_argv); |
179 | perror("Failed to exec kernel" ); |
180 | ret = 1; |
181 | } |
182 | return uml_exitcode; |
183 | } |
184 | |
185 | extern void *__real_malloc(int); |
186 | |
187 | void *__wrap_malloc(int size) |
188 | { |
189 | void *ret; |
190 | |
191 | if (!kmalloc_ok) |
192 | return __real_malloc(size); |
193 | else if (size <= UM_KERN_PAGE_SIZE) |
194 | /* finding contiguous pages can be hard*/ |
195 | ret = uml_kmalloc(size, UM_GFP_KERNEL); |
196 | 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 | if (ret == NULL) |
203 | errno = ENOMEM; |
204 | |
205 | return ret; |
206 | } |
207 | |
208 | void *__wrap_calloc(int n, int size) |
209 | { |
210 | void *ptr = __wrap_malloc(size: n * size); |
211 | |
212 | if (ptr == NULL) |
213 | return NULL; |
214 | memset(ptr, 0, n * size); |
215 | return ptr; |
216 | } |
217 | |
218 | extern void __real_free(void *); |
219 | |
220 | extern unsigned long high_physmem; |
221 | |
222 | void __wrap_free(void *ptr) |
223 | { |
224 | 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 | if ((addr >= uml_physmem) && (addr < high_physmem)) { |
246 | if (kmalloc_ok) |
247 | kfree(ptr); |
248 | } |
249 | else if ((addr >= start_vm) && (addr < end_vm)) { |
250 | if (kmalloc_ok) |
251 | vfree(ptr); |
252 | } |
253 | else __real_free(ptr); |
254 | } |
255 | |