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