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