arch/um/os-Linux/main.c

   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 }