1 /* 2 * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com) 3 * Licensed under the GPL 4 */ 5 6 #include <unistd.h> 7 #include <stdio.h> 8 #include <stdlib.h> 9 #include <string.h> 10 #include <signal.h> 11 #include <errno.h> 12 #include <sys/resource.h> 13 #include <sys/mman.h> 14 #include <sys/user.h> 15 #include <asm/page.h> 16 #include "kern_util.h" 17 #include "as-layout.h" 18 #include "mem_user.h" 19 #include "irq_user.h" 20 #include "user.h" 21 #include "init.h" 22 #include "mode.h" 23 #include "choose-mode.h" 24 #include "uml-config.h" 25 #include "os.h" 26 #include "um_malloc.h" 27 #include "kern_constants.h" 28 29 /* Set in main, unchanged thereafter */ 30 char *linux_prog; 31 32 #define PGD_BOUND (4 * 1024 * 1024) 33 #define STACKSIZE (8 * 1024 * 1024) 34 #define THREAD_NAME_LEN (256) 35 36 static void set_stklim(void) 37 { 38 struct rlimit lim; 39 40 if(getrlimit(RLIMIT_STACK, &lim) < 0){ 41 perror("getrlimit"); 42 exit(1); 43 } 44 if((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)){ 45 lim.rlim_cur = STACKSIZE; 46 if(setrlimit(RLIMIT_STACK, &lim) < 0){ 47 perror("setrlimit"); 48 exit(1); 49 } 50 } 51 } 52 53 static __init void do_uml_initcalls(void) 54 { 55 initcall_t *call; 56 57 call = &__uml_initcall_start; 58 while (call < &__uml_initcall_end){ 59 (*call)(); 60 call++; 61 } 62 } 63 64 static void last_ditch_exit(int sig) 65 { 66 uml_cleanup(); 67 exit(1); 68 } 69 70 static void install_fatal_handler(int sig) 71 { 72 struct sigaction action; 73 74 /* All signals are enabled in this handler ... */ 75 sigemptyset(&action.sa_mask); 76 77 /* ... including the signal being handled, plus we want the 78 * handler reset to the default behavior, so that if an exit 79 * handler is hanging for some reason, the UML will just die 80 * after this signal is sent a second time. 81 */ 82 action.sa_flags = SA_RESETHAND | SA_NODEFER; 83 action.sa_restorer = NULL; 84 action.sa_handler = last_ditch_exit; 85 if(sigaction(sig, &action, NULL) < 0){ 86 printf("failed to install handler for signal %d - errno = %d\n", 87 errno); 88 exit(1); 89 } 90 } 91 92 #define UML_LIB_PATH ":/usr/lib/uml" 93 94 static void setup_env_path(void) 95 { 96 char *new_path = NULL; 97 char *old_path = NULL; 98 int path_len = 0; 99 100 old_path = getenv("PATH"); 101 /* if no PATH variable is set or it has an empty value 102 * just use the default + /usr/lib/uml 103 */ 104 if (!old_path || (path_len = strlen(old_path)) == 0) { 105 putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH); 106 return; 107 } 108 109 /* append /usr/lib/uml to the existing path */ 110 path_len += strlen("PATH=" UML_LIB_PATH) + 1; 111 new_path = malloc(path_len); 112 if (!new_path) { 113 perror("coudn't malloc to set a new PATH"); 114 return; 115 } 116 snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path); 117 putenv(new_path); 118 } 119 120 extern int uml_exitcode; 121 122 extern void scan_elf_aux( char **envp); 123 124 int __init main(int argc, char **argv, char **envp) 125 { 126 char **new_argv; 127 int ret, i, err; 128 129 #ifdef UML_CONFIG_CMDLINE_ON_HOST 130 /* Allocate memory for thread command lines */ 131 if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){ 132 133 char padding[THREAD_NAME_LEN] = { 134 [ 0 ... THREAD_NAME_LEN - 2] = ' ', '\0' 135 }; 136 137 new_argv = malloc((argc + 2) * sizeof(char*)); 138 if(!new_argv) { 139 perror("Allocating extended argv"); 140 exit(1); 141 } 142 143 new_argv[0] = argv[0]; 144 new_argv[1] = padding; 145 146 for(i = 2; i <= argc; i++) 147 new_argv[i] = argv[i - 1]; 148 new_argv[argc + 1] = NULL; 149 150 execvp(new_argv[0], new_argv); 151 perror("execing with extended args"); 152 exit(1); 153 } 154 #endif 155 156 linux_prog = argv[0]; 157 158 set_stklim(); 159 160 setup_env_path(); 161 162 new_argv = malloc((argc + 1) * sizeof(char *)); 163 if(new_argv == NULL){ 164 perror("Mallocing argv"); 165 exit(1); 166 } 167 for(i=0;i<argc;i++){ 168 new_argv[i] = strdup(argv[i]); 169 if(new_argv[i] == NULL){ 170 perror("Mallocing an arg"); 171 exit(1); 172 } 173 } 174 new_argv[argc] = NULL; 175 176 /* Allow these signals to bring down a UML if all other 177 * methods of control fail. 178 */ 179 install_fatal_handler(SIGINT); 180 install_fatal_handler(SIGTERM); 181 install_fatal_handler(SIGHUP); 182 183 scan_elf_aux( envp); 184 185 do_uml_initcalls(); 186 ret = linux_main(argc, argv); 187 188 /* Disable SIGPROF - I have no idea why libc doesn't do this or turn 189 * off the profiling time, but UML dies with a SIGPROF just before 190 * exiting when profiling is active. 191 */ 192 change_sig(SIGPROF, 0); 193 194 /* This signal stuff used to be in the reboot case. However, 195 * sometimes a SIGVTALRM can come in when we're halting (reproducably 196 * when writing out gcov information, presumably because that takes 197 * some time) and cause a segfault. 198 */ 199 200 /* stop timers and set SIG*ALRM to be ignored */ 201 disable_timer(); 202 203 /* disable SIGIO for the fds and set SIGIO to be ignored */ 204 err = deactivate_all_fds(); 205 if(err) 206 printf("deactivate_all_fds failed, errno = %d\n", -err); 207 208 /* Let any pending signals fire now. This ensures 209 * that they won't be delivered after the exec, when 210 * they are definitely not expected. 211 */ 212 unblock_signals(); 213 214 /* Reboot */ 215 if(ret){ 216 printf("\n"); 217 execvp(new_argv[0], new_argv); 218 perror("Failed to exec kernel"); 219 ret = 1; 220 } 221 printf("\n"); 222 return uml_exitcode; 223 } 224 225 #define CAN_KMALLOC() \ 226 (kmalloc_ok && CHOOSE_MODE((os_getpid() != tracing_pid), 1)) 227 228 extern void *__real_malloc(int); 229 230 void *__wrap_malloc(int size) 231 { 232 void *ret; 233 234 if(!CAN_KMALLOC()) 235 return __real_malloc(size); 236 else if(size <= UM_KERN_PAGE_SIZE) 237 /* finding contiguous pages can be hard*/ 238 ret = kmalloc(size, UM_GFP_KERNEL); 239 else ret = vmalloc(size); 240 241 /* glibc people insist that if malloc fails, errno should be 242 * set by malloc as well. So we do. 243 */ 244 if(ret == NULL) 245 errno = ENOMEM; 246 247 return ret; 248 } 249 250 void *__wrap_calloc(int n, int size) 251 { 252 void *ptr = __wrap_malloc(n * size); 253 254 if(ptr == NULL) 255 return NULL; 256 memset(ptr, 0, n * size); 257 return ptr; 258 } 259 260 extern void __real_free(void *); 261 262 extern unsigned long high_physmem; 263 264 void __wrap_free(void *ptr) 265 { 266 unsigned long addr = (unsigned long) ptr; 267 268 /* We need to know how the allocation happened, so it can be correctly 269 * freed. This is done by seeing what region of memory the pointer is 270 * in - 271 * physical memory - kmalloc/kfree 272 * kernel virtual memory - vmalloc/vfree 273 * anywhere else - malloc/free 274 * If kmalloc is not yet possible, then either high_physmem and/or 275 * end_vm are still 0 (as at startup), in which case we call free, or 276 * we have set them, but anyway addr has not been allocated from those 277 * areas. So, in both cases __real_free is called. 278 * 279 * CAN_KMALLOC is checked because it would be bad to free a buffer 280 * with kmalloc/vmalloc after they have been turned off during 281 * shutdown. 282 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so 283 * there is a possibility for memory leaks. 284 */ 285 286 if((addr >= uml_physmem) && (addr < high_physmem)){ 287 if(CAN_KMALLOC()) 288 kfree(ptr); 289 } 290 else if((addr >= start_vm) && (addr < end_vm)){ 291 if(CAN_KMALLOC()) 292 vfree(ptr); 293 } 294 else __real_free(ptr); 295 } 296