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         signal(SIGINT, SIG_DFL);
  71         signal(SIGTERM, SIG_DFL);
  72         signal(SIGHUP, SIG_DFL);
  73         uml_cleanup();
  74         exit(1);
  75 }
  76
  77 extern int uml_exitcode;
  78
  79 extern void scan_elf_aux( char **envp);
  80
  81 int main(int argc, char **argv, char **envp)
  82 {
  83         char **new_argv;
  84         sigset_t mask;
  85         int ret, i, err;
  86
  87         /* Enable all signals except SIGIO - in some environments, we can
  88          * enter with some signals blocked
  89          */
  90
  91         sigemptyset(&mask);
  92         sigaddset(&mask, SIGIO);
  93         if(sigprocmask(SIG_SETMASK, &mask, NULL) < 0){
  94                 perror("sigprocmask");
  95                 exit(1);
  96         }
  97
  98 #ifdef UML_CONFIG_CMDLINE_ON_HOST
  99         /* Allocate memory for thread command lines */
 100         if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){
 101
 102                 char padding[THREAD_NAME_LEN] = {
 103                         [ 0 ...  THREAD_NAME_LEN - 2] = ' ', '\0'
 104                 };
 105
 106                 new_argv = malloc((argc + 2) * sizeof(char*));
 107                 if(!new_argv) {
 108                         perror("Allocating extended argv");
 109                         exit(1);
 110                 }
 111
 112                 new_argv[0] = argv[0];
 113                 new_argv[1] = padding;
 114
 115                 for(i = 2; i <= argc; i++)
 116                         new_argv[i] = argv[i - 1];
 117                 new_argv[argc + 1] = NULL;
 118
 119                 execvp(new_argv[0], new_argv);
 120                 perror("execing with extended args");
 121                 exit(1);
 122         }
 123 #endif
 124
 125         linux_prog = argv[0];
 126
 127         set_stklim();
 128
 129         new_argv = malloc((argc + 1) * sizeof(char *));
 130         if(new_argv == NULL){
 131                 perror("Mallocing argv");
 132                 exit(1);
 133         }
 134         for(i=0;i<argc;i++){
 135                 new_argv[i] = strdup(argv[i]);
 136                 if(new_argv[i] == NULL){
 137                         perror("Mallocing an arg");
 138                         exit(1);
 139                 }
 140         }
 141         new_argv[argc] = NULL;
 142
 143         set_handler(SIGINT, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 144         set_handler(SIGTERM, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 145         set_handler(SIGHUP, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 146
 147         scan_elf_aux( envp);
 148
 149         do_uml_initcalls();
 150         ret = linux_main(argc, argv);
 151
 152         /* Disable SIGPROF - I have no idea why libc doesn't do this or turn
 153          * off the profiling time, but UML dies with a SIGPROF just before
 154          * exiting when profiling is active.
 155          */
 156         change_sig(SIGPROF, 0);
 157
 158         /* This signal stuff used to be in the reboot case.  However,
 159          * sometimes a SIGVTALRM can come in when we're halting (reproducably
 160          * when writing out gcov information, presumably because that takes
 161          * some time) and cause a segfault.
 162          */
 163
 164         /* stop timers and set SIG*ALRM to be ignored */
 165         disable_timer();
 166
 167         /* disable SIGIO for the fds and set SIGIO to be ignored */
 168         err = deactivate_all_fds();
 169         if(err)
 170                 printf("deactivate_all_fds failed, errno = %d\n", -err);
 171
 172         /* Let any pending signals fire now.  This ensures
 173          * that they won't be delivered after the exec, when
 174          * they are definitely not expected.
 175          */
 176         unblock_signals();
 177
 178         /* Reboot */
 179         if(ret){
 180                 printf("\n");
 181                 execvp(new_argv[0], new_argv);
 182                 perror("Failed to exec kernel");
 183                 ret = 1;
 184         }
 185         printf("\n");
 186         return(uml_exitcode);
 187 }
 188
 189 #define CAN_KMALLOC() \
 190         (kmalloc_ok && CHOOSE_MODE((os_getpid() != tracing_pid), 1))
 191
 192 extern void *__real_malloc(int);
 193
 194 void *__wrap_malloc(int size)
 195 {
 196         void *ret;
 197
 198         if(!CAN_KMALLOC())
 199                 return(__real_malloc(size));
 200         else if(size <= PAGE_SIZE) /* finding contiguos pages can be hard*/
 201                 ret = um_kmalloc(size);
 202         else ret = um_vmalloc(size);
 203
 204         /* glibc people insist that if malloc fails, errno should be
 205          * set by malloc as well. So we do.
 206          */
 207         if(ret == NULL)
 208                 errno = ENOMEM;
 209
 210         return(ret);
 211 }
 212
 213 void *__wrap_calloc(int n, int size)
 214 {
 215         void *ptr = __wrap_malloc(n * size);
 216
 217         if(ptr == NULL) return(NULL);
 218         memset(ptr, 0, n * size);
 219         return(ptr);
 220 }
 221
 222 extern void __real_free(void *);
 223
 224 extern unsigned long high_physmem;
 225
 226 void __wrap_free(void *ptr)
 227 {
 228         unsigned long addr = (unsigned long) ptr;
 229
 230         /* We need to know how the allocation happened, so it can be correctly
 231          * freed.  This is done by seeing what region of memory the pointer is
 232          * in -
 233          *      physical memory - kmalloc/kfree
 234          *      kernel virtual memory - vmalloc/vfree
 235          *      anywhere else - malloc/free
 236          * If kmalloc is not yet possible, then either high_physmem and/or
 237          * end_vm are still 0 (as at startup), in which case we call free, or
 238          * we have set them, but anyway addr has not been allocated from those
 239          * areas. So, in both cases __real_free is called.
 240          *
 241          * CAN_KMALLOC is checked because it would be bad to free a buffer
 242          * with kmalloc/vmalloc after they have been turned off during
 243          * shutdown.
 244          * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
 245          * there is a possibility for memory leaks.
 246          */
 247
 248         if((addr >= uml_physmem) && (addr < high_physmem)){
 249                 if(CAN_KMALLOC())
 250                         kfree(ptr);
 251         }
 252         else if((addr >= start_vm) && (addr < end_vm)){
 253                 if(CAN_KMALLOC())
 254                         vfree(ptr);
 255         }
 256         else __real_free(ptr);
 257 }