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 "user_util.h" 17 #include "kern_util.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 set_stklim, which is called from main and __wrap_malloc. 29 * __wrap_malloc only calls it if main hasn't started. 30 */ 31 unsigned long stacksizelim; 32 33 /* Set in main */ 34 char *linux_prog; 35 36 #define PGD_BOUND (4 * 1024 * 1024) 37 #define STACKSIZE (8 * 1024 * 1024) 38 #define THREAD_NAME_LEN (256) 39 40 static void set_stklim(void) 41 { 42 struct rlimit lim; 43 44 if(getrlimit(RLIMIT_STACK, &lim) < 0){ 45 perror("getrlimit"); 46 exit(1); 47 } 48 if((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)){ 49 lim.rlim_cur = STACKSIZE; 50 if(setrlimit(RLIMIT_STACK, &lim) < 0){ 51 perror("setrlimit"); 52 exit(1); 53 } 54 } 55 stacksizelim = (lim.rlim_cur + PGD_BOUND - 1) & ~(PGD_BOUND - 1); 56 } 57 58 static __init void do_uml_initcalls(void) 59 { 60 initcall_t *call; 61 62 call = &__uml_initcall_start; 63 while (call < &__uml_initcall_end){ 64 (*call)(); 65 call++; 66 } 67 } 68 69 static void last_ditch_exit(int sig) 70 { 71 uml_cleanup(); 72 exit(1); 73 } 74 75 static void install_fatal_handler(int sig) 76 { 77 struct sigaction action; 78 79 /* All signals are enabled in this handler ... */ 80 sigemptyset(&action.sa_mask); 81 82 /* ... including the signal being handled, plus we want the 83 * handler reset to the default behavior, so that if an exit 84 * handler is hanging for some reason, the UML will just die 85 * after this signal is sent a second time. 86 */ 87 action.sa_flags = SA_RESETHAND | SA_NODEFER; 88 action.sa_restorer = NULL; 89 action.sa_handler = last_ditch_exit; 90 if(sigaction(sig, &action, NULL) < 0){ 91 printf("failed to install handler for signal %d - errno = %d\n", 92 errno); 93 exit(1); 94 } 95 } 96 97 #define UML_LIB_PATH ":/usr/lib/uml" 98 99 static void setup_env_path(void) 100 { 101 char *new_path = NULL; 102 char *old_path = NULL; 103 int path_len = 0; 104 105 old_path = getenv("PATH"); 106 /* if no PATH variable is set or it has an empty value 107 * just use the default + /usr/lib/uml 108 */ 109 if (!old_path || (path_len = strlen(old_path)) == 0) { 110 putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH); 111 return; 112 } 113 114 /* append /usr/lib/uml to the existing path */ 115 path_len += strlen("PATH=" UML_LIB_PATH) + 1; 116 new_path = malloc(path_len); 117 if (!new_path) { 118 perror("coudn't malloc to set a new PATH"); 119 return; 120 } 121 snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path); 122 putenv(new_path); 123 } 124 125 extern int uml_exitcode; 126 127 extern void scan_elf_aux( char **envp); 128 129 int main(int argc, char **argv, char **envp) 130 { 131 char **new_argv; 132 int ret, i, err; 133 134 #ifdef UML_CONFIG_CMDLINE_ON_HOST 135 /* Allocate memory for thread command lines */ 136 if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){ 137 138 char padding[THREAD_NAME_LEN] = { 139 [ 0 ... THREAD_NAME_LEN - 2] = ' ', '\0' 140 }; 141 142 new_argv = malloc((argc + 2) * sizeof(char*)); 143 if(!new_argv) { 144 perror("Allocating extended argv"); 145 exit(1); 146 } 147 148 new_argv[0] = argv[0]; 149 new_argv[1] = padding; 150 151 for(i = 2; i <= argc; i++) 152 new_argv[i] = argv[i - 1]; 153 new_argv[argc + 1] = NULL; 154 155 execvp(new_argv[0], new_argv); 156 perror("execing with extended args"); 157 exit(1); 158 } 159 #endif 160 161 linux_prog = argv[0]; 162 163 set_stklim(); 164 165 setup_env_path(); 166 167 new_argv = malloc((argc + 1) * sizeof(char *)); 168 if(new_argv == NULL){ 169 perror("Mallocing argv"); 170 exit(1); 171 } 172 for(i=0;i<argc;i++){ 173 new_argv[i] = strdup(argv[i]); 174 if(new_argv[i] == NULL){ 175 perror("Mallocing an arg"); 176 exit(1); 177 } 178 } 179 new_argv[argc] = NULL; 180 181 /* Allow these signals to bring down a UML if all other 182 * methods of control fail. 183 */ 184 install_fatal_handler(SIGINT); 185 install_fatal_handler(SIGTERM); 186 install_fatal_handler(SIGHUP); 187 188 scan_elf_aux( envp); 189 190 do_uml_initcalls(); 191 ret = linux_main(argc, argv); 192 193 /* Disable SIGPROF - I have no idea why libc doesn't do this or turn 194 * off the profiling time, but UML dies with a SIGPROF just before 195 * exiting when profiling is active. 196 */ 197 change_sig(SIGPROF, 0); 198 199 /* This signal stuff used to be in the reboot case. However, 200 * sometimes a SIGVTALRM can come in when we're halting (reproducably 201 * when writing out gcov information, presumably because that takes 202 * some time) and cause a segfault. 203 */ 204 205 /* stop timers and set SIG*ALRM to be ignored */ 206 disable_timer(); 207 208 /* disable SIGIO for the fds and set SIGIO to be ignored */ 209 err = deactivate_all_fds(); 210 if(err) 211 printf("deactivate_all_fds failed, errno = %d\n", -err); 212 213 /* Let any pending signals fire now. This ensures 214 * that they won't be delivered after the exec, when 215 * they are definitely not expected. 216 */ 217 unblock_signals(); 218 219 /* Reboot */ 220 if(ret){ 221 printf("\n"); 222 execvp(new_argv[0], new_argv); 223 perror("Failed to exec kernel"); 224 ret = 1; 225 } 226 printf("\n"); 227 return(uml_exitcode); 228 } 229 230 #define CAN_KMALLOC() \ 231 (kmalloc_ok && CHOOSE_MODE((os_getpid() != tracing_pid), 1)) 232 233 extern void *__real_malloc(int); 234 235 void *__wrap_malloc(int size) 236 { 237 void *ret; 238 239 if(!CAN_KMALLOC()) 240 return(__real_malloc(size)); 241 else if(size <= PAGE_SIZE) /* finding contiguos pages can be hard*/ 242 ret = um_kmalloc(size); 243 else ret = um_vmalloc(size); 244 245 /* glibc people insist that if malloc fails, errno should be 246 * set by malloc as well. So we do. 247 */ 248 if(ret == NULL) 249 errno = ENOMEM; 250 251 return(ret); 252 } 253 254 void *__wrap_calloc(int n, int size) 255 { 256 void *ptr = __wrap_malloc(n * size); 257 258 if(ptr == NULL) return(NULL); 259 memset(ptr, 0, n * size); 260 return(ptr); 261 } 262 263 extern void __real_free(void *); 264 265 extern unsigned long high_physmem; 266 267 void __wrap_free(void *ptr) 268 { 269 unsigned long addr = (unsigned long) ptr; 270 271 /* We need to know how the allocation happened, so it can be correctly 272 * freed. This is done by seeing what region of memory the pointer is 273 * in - 274 * physical memory - kmalloc/kfree 275 * kernel virtual memory - vmalloc/vfree 276 * anywhere else - malloc/free 277 * If kmalloc is not yet possible, then either high_physmem and/or 278 * end_vm are still 0 (as at startup), in which case we call free, or 279 * we have set them, but anyway addr has not been allocated from those 280 * areas. So, in both cases __real_free is called. 281 * 282 * CAN_KMALLOC is checked because it would be bad to free a buffer 283 * with kmalloc/vmalloc after they have been turned off during 284 * shutdown. 285 * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so 286 * there is a possibility for memory leaks. 287 */ 288 289 if((addr >= uml_physmem) && (addr < high_physmem)){ 290 if(CAN_KMALLOC()) 291 kfree(ptr); 292 } 293 else if((addr >= start_vm) && (addr < end_vm)){ 294 if(CAN_KMALLOC()) 295 vfree(ptr); 296 } 297 else __real_free(ptr); 298 } 299