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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
24long elf_aux_hwcap;
25
26static 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
43static void last_ditch_exit(int sig)
44{
45 uml_cleanup();
46 exit(1);
47}
48
49static 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
74static 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
105extern void scan_elf_aux( char **envp);
106
107int __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
185extern void *__real_malloc(int);
186
187void *__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
208void *__wrap_calloc(int n, int size)
209{
210 void *ptr = __wrap_malloc(n * size);
211
212 if (ptr == NULL)
213 return NULL;
214 memset(ptr, 0, n * size);
215 return ptr;
216}
217
218extern void __real_free(void *);
219
220extern unsigned long high_physmem;
221
222void __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}
1/*
2 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
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
24long elf_aux_hwcap;
25
26static 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
43static __init void do_uml_initcalls(void)
44{
45 initcall_t *call;
46
47 call = &__uml_initcall_start;
48 while (call < &__uml_initcall_end) {
49 (*call)();
50 call++;
51 }
52}
53
54static void last_ditch_exit(int sig)
55{
56 uml_cleanup();
57 exit(1);
58}
59
60static void install_fatal_handler(int sig)
61{
62 struct sigaction action;
63
64 /* All signals are enabled in this handler ... */
65 sigemptyset(&action.sa_mask);
66
67 /*
68 * ... including the signal being handled, plus we want the
69 * handler reset to the default behavior, so that if an exit
70 * handler is hanging for some reason, the UML will just die
71 * after this signal is sent a second time.
72 */
73 action.sa_flags = SA_RESETHAND | SA_NODEFER;
74 action.sa_restorer = NULL;
75 action.sa_handler = last_ditch_exit;
76 if (sigaction(sig, &action, NULL) < 0) {
77 os_warn("failed to install handler for signal %d "
78 "- errno = %d\n", sig, errno);
79 exit(1);
80 }
81}
82
83#define UML_LIB_PATH ":" OS_LIB_PATH "/uml"
84
85static void setup_env_path(void)
86{
87 char *new_path = NULL;
88 char *old_path = NULL;
89 int path_len = 0;
90
91 old_path = getenv("PATH");
92 /*
93 * if no PATH variable is set or it has an empty value
94 * just use the default + /usr/lib/uml
95 */
96 if (!old_path || (path_len = strlen(old_path)) == 0) {
97 if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH))
98 perror("couldn't putenv");
99 return;
100 }
101
102 /* append /usr/lib/uml to the existing path */
103 path_len += strlen("PATH=" UML_LIB_PATH) + 1;
104 new_path = malloc(path_len);
105 if (!new_path) {
106 perror("couldn't malloc to set a new PATH");
107 return;
108 }
109 snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
110 if (putenv(new_path)) {
111 perror("couldn't putenv to set a new PATH");
112 free(new_path);
113 }
114}
115
116extern void scan_elf_aux( char **envp);
117
118int __init main(int argc, char **argv, char **envp)
119{
120 char **new_argv;
121 int ret, i, err;
122
123 set_stklim();
124
125 setup_env_path();
126
127 setsid();
128
129 new_argv = malloc((argc + 1) * sizeof(char *));
130 if (new_argv == NULL) {
131 perror("Mallocing argv");
132 exit(1);
133 }
134 for (i = 0; i < argc; i++) {
135 new_argv[i] = strdup(argv[i]);
136 if (new_argv[i] == NULL) {
137 perror("Mallocing an arg");
138 exit(1);
139 }
140 }
141 new_argv[argc] = NULL;
142
143 /*
144 * Allow these signals to bring down a UML if all other
145 * methods of control fail.
146 */
147 install_fatal_handler(SIGINT);
148 install_fatal_handler(SIGTERM);
149
150#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
151 scan_elf_aux(envp);
152#endif
153
154 do_uml_initcalls();
155 change_sig(SIGPIPE, 0);
156 ret = linux_main(argc, argv);
157
158 /*
159 * Disable SIGPROF - I have no idea why libc doesn't do this or turn
160 * off the profiling time, but UML dies with a SIGPROF just before
161 * exiting when profiling is active.
162 */
163 change_sig(SIGPROF, 0);
164
165 /*
166 * This signal stuff used to be in the reboot case. However,
167 * sometimes a timer signal can come in when we're halting (reproducably
168 * when writing out gcov information, presumably because that takes
169 * some time) and cause a segfault.
170 */
171
172 /* stop timers and set timer signal to be ignored */
173 os_timer_disable();
174
175 /* disable SIGIO for the fds and set SIGIO to be ignored */
176 err = deactivate_all_fds();
177 if (err)
178 os_warn("deactivate_all_fds failed, errno = %d\n", -err);
179
180 /*
181 * Let any pending signals fire now. This ensures
182 * that they won't be delivered after the exec, when
183 * they are definitely not expected.
184 */
185 unblock_signals();
186
187 os_info("\n");
188 /* Reboot */
189 if (ret) {
190 execvp(new_argv[0], new_argv);
191 perror("Failed to exec kernel");
192 ret = 1;
193 }
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}