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 #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 }