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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 <sys/personality.h>
15#include <as-layout.h>
16#include <init.h>
17#include <kern_util.h>
18#include <os.h>
19#include <um_malloc.h>
20#include "internal.h"
21
22#define PGD_BOUND (4 * 1024 * 1024)
23#define STACKSIZE (8 * 1024 * 1024)
24#define THREAD_NAME_LEN (256)
25
26long elf_aux_hwcap;
27
28static void set_stklim(void)
29{
30 struct rlimit lim;
31
32 if (getrlimit(RLIMIT_STACK, &lim) < 0) {
33 perror("getrlimit");
34 exit(1);
35 }
36 if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) {
37 lim.rlim_cur = STACKSIZE;
38 if (setrlimit(RLIMIT_STACK, &lim) < 0) {
39 perror("setrlimit");
40 exit(1);
41 }
42 }
43}
44
45static void last_ditch_exit(int sig)
46{
47 uml_cleanup();
48 exit(1);
49}
50
51static void install_fatal_handler(int sig)
52{
53 struct sigaction action;
54
55 /* All signals are enabled in this handler ... */
56 sigemptyset(&action.sa_mask);
57
58 /*
59 * ... including the signal being handled, plus we want the
60 * handler reset to the default behavior, so that if an exit
61 * handler is hanging for some reason, the UML will just die
62 * after this signal is sent a second time.
63 */
64 action.sa_flags = SA_RESETHAND | SA_NODEFER;
65 action.sa_restorer = NULL;
66 action.sa_handler = last_ditch_exit;
67 if (sigaction(sig, &action, NULL) < 0) {
68 os_warn("failed to install handler for signal %d "
69 "- errno = %d\n", sig, errno);
70 exit(1);
71 }
72}
73
74#define UML_LIB_PATH ":" OS_LIB_PATH "/uml"
75
76static void setup_env_path(void)
77{
78 char *new_path = NULL;
79 char *old_path = NULL;
80 int path_len = 0;
81
82 old_path = getenv("PATH");
83 /*
84 * if no PATH variable is set or it has an empty value
85 * just use the default + /usr/lib/uml
86 */
87 if (!old_path || (path_len = strlen(old_path)) == 0) {
88 if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH))
89 perror("couldn't putenv");
90 return;
91 }
92
93 /* append /usr/lib/uml to the existing path */
94 path_len += strlen("PATH=" UML_LIB_PATH) + 1;
95 new_path = malloc(path_len);
96 if (!new_path) {
97 perror("couldn't malloc to set a new PATH");
98 return;
99 }
100 snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
101 if (putenv(new_path)) {
102 perror("couldn't putenv to set a new PATH");
103 free(new_path);
104 }
105}
106
107int __init main(int argc, char **argv, char **envp)
108{
109 char **new_argv;
110 int ret, i, err;
111
112 /* Disable randomization and re-exec if it was changed successfully */
113 ret = personality(PER_LINUX | ADDR_NO_RANDOMIZE);
114 if (ret >= 0 && (ret & (PER_LINUX | ADDR_NO_RANDOMIZE)) !=
115 (PER_LINUX | ADDR_NO_RANDOMIZE)) {
116 char buf[4096] = {};
117 ssize_t ret;
118
119 ret = readlink("/proc/self/exe", buf, sizeof(buf));
120 if (ret < 0 || ret >= sizeof(buf)) {
121 perror("readlink failure");
122 exit(1);
123 }
124 execve(buf, argv, envp);
125 }
126
127 set_stklim();
128
129 setup_env_path();
130
131 setsid();
132
133 new_argv = malloc((argc + 1) * sizeof(char *));
134 if (new_argv == NULL) {
135 perror("Mallocing argv");
136 exit(1);
137 }
138 for (i = 0; i < argc; i++) {
139 new_argv[i] = strdup(argv[i]);
140 if (new_argv[i] == NULL) {
141 perror("Mallocing an arg");
142 exit(1);
143 }
144 }
145 new_argv[argc] = NULL;
146
147 /*
148 * Allow these signals to bring down a UML if all other
149 * methods of control fail.
150 */
151 install_fatal_handler(SIGINT);
152 install_fatal_handler(SIGTERM);
153
154#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
155 scan_elf_aux(envp);
156#endif
157
158 change_sig(SIGPIPE, 0);
159 ret = linux_main(argc, argv, envp);
160
161 /*
162 * Disable SIGPROF - I have no idea why libc doesn't do this or turn
163 * off the profiling time, but UML dies with a SIGPROF just before
164 * exiting when profiling is active.
165 */
166 change_sig(SIGPROF, 0);
167
168 /*
169 * This signal stuff used to be in the reboot case. However,
170 * sometimes a timer signal can come in when we're halting (reproducably
171 * when writing out gcov information, presumably because that takes
172 * some time) and cause a segfault.
173 */
174
175 /* stop timers and set timer signal to be ignored */
176 os_timer_disable();
177
178 /* disable SIGIO for the fds and set SIGIO to be ignored */
179 err = deactivate_all_fds();
180 if (err)
181 os_warn("deactivate_all_fds failed, errno = %d\n", -err);
182
183 /*
184 * Let any pending signals fire now. This ensures
185 * that they won't be delivered after the exec, when
186 * they are definitely not expected.
187 */
188 unblock_signals();
189
190 os_info("\n");
191 /* Reboot */
192 if (ret) {
193 execvp(new_argv[0], new_argv);
194 perror("Failed to exec kernel");
195 ret = 1;
196 }
197 return uml_exitcode;
198}
199
200extern void *__real_malloc(int);
201extern void __real_free(void *);
202
203/* workaround for -Wmissing-prototypes warnings */
204void *__wrap_malloc(int size);
205void *__wrap_calloc(int n, int size);
206void __wrap_free(void *ptr);
207
208void *__wrap_malloc(int size)
209{
210 void *ret;
211
212 if (!kmalloc_ok)
213 return __real_malloc(size);
214 else if (size <= UM_KERN_PAGE_SIZE)
215 /* finding contiguous pages can be hard*/
216 ret = uml_kmalloc(size, UM_GFP_KERNEL);
217 else ret = vmalloc(size);
218
219 /*
220 * glibc people insist that if malloc fails, errno should be
221 * set by malloc as well. So we do.
222 */
223 if (ret == NULL)
224 errno = ENOMEM;
225
226 return ret;
227}
228
229void *__wrap_calloc(int n, int size)
230{
231 void *ptr = __wrap_malloc(n * size);
232
233 if (ptr == NULL)
234 return NULL;
235 memset(ptr, 0, n * size);
236 return ptr;
237}
238
239void __wrap_free(void *ptr)
240{
241 unsigned long addr = (unsigned long) ptr;
242
243 /*
244 * We need to know how the allocation happened, so it can be correctly
245 * freed. This is done by seeing what region of memory the pointer is
246 * in -
247 * physical memory - kmalloc/kfree
248 * kernel virtual memory - vmalloc/vfree
249 * anywhere else - malloc/free
250 * If kmalloc is not yet possible, then either high_physmem and/or
251 * end_vm are still 0 (as at startup), in which case we call free, or
252 * we have set them, but anyway addr has not been allocated from those
253 * areas. So, in both cases __real_free is called.
254 *
255 * CAN_KMALLOC is checked because it would be bad to free a buffer
256 * with kmalloc/vmalloc after they have been turned off during
257 * shutdown.
258 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
259 * there is a possibility for memory leaks.
260 */
261
262 if ((addr >= uml_physmem) && (addr < high_physmem)) {
263 if (kmalloc_ok)
264 kfree(ptr);
265 }
266 else if ((addr >= start_vm) && (addr < end_vm)) {
267 if (kmalloc_ok)
268 vfree(ptr);
269 }
270 else __real_free(ptr);
271}
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_constants.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 printf("failed to install handler for signal %d - errno = %d\n",
78 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 new_argv = malloc((argc + 1) * sizeof(char *));
128 if (new_argv == NULL) {
129 perror("Mallocing argv");
130 exit(1);
131 }
132 for (i = 0; i < argc; i++) {
133 new_argv[i] = strdup(argv[i]);
134 if (new_argv[i] == NULL) {
135 perror("Mallocing an arg");
136 exit(1);
137 }
138 }
139 new_argv[argc] = NULL;
140
141 /*
142 * Allow these signals to bring down a UML if all other
143 * methods of control fail.
144 */
145 install_fatal_handler(SIGINT);
146 install_fatal_handler(SIGTERM);
147
148#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
149 scan_elf_aux(envp);
150#endif
151
152 do_uml_initcalls();
153 ret = linux_main(argc, argv);
154
155 /*
156 * Disable SIGPROF - I have no idea why libc doesn't do this or turn
157 * off the profiling time, but UML dies with a SIGPROF just before
158 * exiting when profiling is active.
159 */
160 change_sig(SIGPROF, 0);
161
162 /*
163 * This signal stuff used to be in the reboot case. However,
164 * sometimes a SIGVTALRM can come in when we're halting (reproducably
165 * when writing out gcov information, presumably because that takes
166 * some time) and cause a segfault.
167 */
168
169 /* stop timers and set SIGVTALRM to be ignored */
170 disable_timer();
171
172 /* disable SIGIO for the fds and set SIGIO to be ignored */
173 err = deactivate_all_fds();
174 if (err)
175 printf("deactivate_all_fds failed, errno = %d\n", -err);
176
177 /*
178 * Let any pending signals fire now. This ensures
179 * that they won't be delivered after the exec, when
180 * they are definitely not expected.
181 */
182 unblock_signals();
183
184 /* Reboot */
185 if (ret) {
186 printf("\n");
187 execvp(new_argv[0], new_argv);
188 perror("Failed to exec kernel");
189 ret = 1;
190 }
191 printf("\n");
192 return uml_exitcode;
193}
194
195extern void *__real_malloc(int);
196
197void *__wrap_malloc(int size)
198{
199 void *ret;
200
201 if (!kmalloc_ok)
202 return __real_malloc(size);
203 else if (size <= UM_KERN_PAGE_SIZE)
204 /* finding contiguous pages can be hard*/
205 ret = uml_kmalloc(size, UM_GFP_KERNEL);
206 else ret = vmalloc(size);
207
208 /*
209 * glibc people insist that if malloc fails, errno should be
210 * set by malloc as well. So we do.
211 */
212 if (ret == NULL)
213 errno = ENOMEM;
214
215 return ret;
216}
217
218void *__wrap_calloc(int n, int size)
219{
220 void *ptr = __wrap_malloc(n * size);
221
222 if (ptr == NULL)
223 return NULL;
224 memset(ptr, 0, n * size);
225 return ptr;
226}
227
228extern void __real_free(void *);
229
230extern unsigned long high_physmem;
231
232void __wrap_free(void *ptr)
233{
234 unsigned long addr = (unsigned long) ptr;
235
236 /*
237 * We need to know how the allocation happened, so it can be correctly
238 * freed. This is done by seeing what region of memory the pointer is
239 * in -
240 * physical memory - kmalloc/kfree
241 * kernel virtual memory - vmalloc/vfree
242 * anywhere else - malloc/free
243 * If kmalloc is not yet possible, then either high_physmem and/or
244 * end_vm are still 0 (as at startup), in which case we call free, or
245 * we have set them, but anyway addr has not been allocated from those
246 * areas. So, in both cases __real_free is called.
247 *
248 * CAN_KMALLOC is checked because it would be bad to free a buffer
249 * with kmalloc/vmalloc after they have been turned off during
250 * shutdown.
251 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
252 * there is a possibility for memory leaks.
253 */
254
255 if ((addr >= uml_physmem) && (addr < high_physmem)) {
256 if (kmalloc_ok)
257 kfree(ptr);
258 }
259 else if ((addr >= start_vm) && (addr < end_vm)) {
260 if (kmalloc_ok)
261 vfree(ptr);
262 }
263 else __real_free(ptr);
264}