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