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 23 long elf_aux_hwcap; 24 25 static 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 42 static __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 53 static void last_ditch_exit(int sig) 54 { 55 uml_cleanup(); 56 exit(1); 57 } 58 59 static 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 84 static 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 } 114 115 extern void scan_elf_aux( char **envp); 116 117 int __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 new_argv = malloc((argc + 1) * sizeof(char *)); 127 if (new_argv == NULL) { 128 perror("Mallocing argv"); 129 exit(1); 130 } 131 for (i = 0; i < argc; i++) { 132 new_argv[i] = strdup(argv[i]); 133 if (new_argv[i] == NULL) { 134 perror("Mallocing an arg"); 135 exit(1); 136 } 137 } 138 new_argv[argc] = NULL; 139 140 /* 141 * Allow these signals to bring down a UML if all other 142 * methods of control fail. 143 */ 144 install_fatal_handler(SIGINT); 145 install_fatal_handler(SIGTERM); 146 147 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 148 scan_elf_aux(envp); 149 #endif 150 151 do_uml_initcalls(); 152 ret = linux_main(argc, argv); 153 154 /* 155 * Disable SIGPROF - I have no idea why libc doesn't do this or turn 156 * off the profiling time, but UML dies with a SIGPROF just before 157 * exiting when profiling is active. 158 */ 159 change_sig(SIGPROF, 0); 160 161 /* 162 * This signal stuff used to be in the reboot case. However, 163 * sometimes a SIGVTALRM can come in when we're halting (reproducably 164 * when writing out gcov information, presumably because that takes 165 * some time) and cause a segfault. 166 */ 167 168 /* stop timers and set SIGVTALRM to be ignored */ 169 disable_timer(); 170 171 /* disable SIGIO for the fds and set SIGIO to be ignored */ 172 err = deactivate_all_fds(); 173 if (err) 174 printf("deactivate_all_fds failed, errno = %d\n", -err); 175 176 /* 177 * Let any pending signals fire now. This ensures 178 * that they won't be delivered after the exec, when 179 * they are definitely not expected. 180 */ 181 unblock_signals(); 182 183 /* Reboot */ 184 if (ret) { 185 printf("\n"); 186 execvp(new_argv[0], new_argv); 187 perror("Failed to exec kernel"); 188 ret = 1; 189 } 190 printf("\n"); 191 return uml_exitcode; 192 } 193 194 extern void *__real_malloc(int); 195 196 void *__wrap_malloc(int size) 197 { 198 void *ret; 199 200 if (!kmalloc_ok) 201 return __real_malloc(size); 202 else if (size <= UM_KERN_PAGE_SIZE) 203 /* finding contiguous pages can be hard*/ 204 ret = uml_kmalloc(size, UM_GFP_KERNEL); 205 else ret = vmalloc(size); 206 207 /* 208 * glibc people insist that if malloc fails, errno should be 209 * set by malloc as well. So we do. 210 */ 211 if (ret == NULL) 212 errno = ENOMEM; 213 214 return ret; 215 } 216 217 void *__wrap_calloc(int n, int size) 218 { 219 void *ptr = __wrap_malloc(n * size); 220 221 if (ptr == NULL) 222 return NULL; 223 memset(ptr, 0, n * size); 224 return ptr; 225 } 226 227 extern void __real_free(void *); 228 229 extern unsigned long high_physmem; 230 231 void __wrap_free(void *ptr) 232 { 233 unsigned long addr = (unsigned long) ptr; 234 235 /* 236 * We need to know how the allocation happened, so it can be correctly 237 * freed. This is done by seeing what region of memory the pointer is 238 * in - 239 * physical memory - kmalloc/kfree 240 * kernel virtual memory - vmalloc/vfree 241 * anywhere else - malloc/free 242 * If kmalloc is not yet possible, then either high_physmem and/or 243 * end_vm are still 0 (as at startup), in which case we call free, or 244 * we have set them, but anyway addr has not been allocated from those 245 * areas. So, in both cases __real_free is called. 246 * 247 * CAN_KMALLOC is checked because it would be bad to free a buffer 248 * with kmalloc/vmalloc after they have been turned off during 249 * shutdown. 250 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so 251 * there is a possibility for memory leaks. 252 */ 253 254 if ((addr >= uml_physmem) && (addr < high_physmem)) { 255 if (kmalloc_ok) 256 kfree(ptr); 257 } 258 else if ((addr >= start_vm) && (addr < end_vm)) { 259 if (kmalloc_ok) 260 vfree(ptr); 261 } 262 else __real_free(ptr); 263 } 264