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 #define UML_LIB_PATH    ":/usr/lib/uml"
  78
  79 static void setup_env_path(void)
  80 {
  81         char *new_path = NULL;
  82         char *old_path = NULL;
  83         int path_len = 0;
  84
  85         old_path = getenv("PATH");
  86         /* if no PATH variable is set or it has an empty value
  87          * just use the default + /usr/lib/uml
  88          */
  89         if (!old_path || (path_len = strlen(old_path)) == 0) {
  90                 putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH);
  91                 return;
  92         }
  93
  94         /* append /usr/lib/uml to the existing path */
  95         path_len += strlen("PATH=" UML_LIB_PATH) + 1;
  96         new_path = malloc(path_len);
  97         if (!new_path) {
  98                 perror("coudn't malloc to set a new PATH");
  99                 return;
 100         }
 101         snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
 102         putenv(new_path);
 103 }
 104
 105 extern int uml_exitcode;
 106
 107 extern void scan_elf_aux( char **envp);
 108
 109 int main(int argc, char **argv, char **envp)
 110 {
 111         char **new_argv;
 112         int ret, i, err;
 113
 114 #ifdef UML_CONFIG_CMDLINE_ON_HOST
 115         /* Allocate memory for thread command lines */
 116         if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){
 117
 118                 char padding[THREAD_NAME_LEN] = {
 119                         [ 0 ...  THREAD_NAME_LEN - 2] = ' ', '\0'
 120                 };
 121
 122                 new_argv = malloc((argc + 2) * sizeof(char*));
 123                 if(!new_argv) {
 124                         perror("Allocating extended argv");
 125                         exit(1);
 126                 }
 127
 128                 new_argv[0] = argv[0];
 129                 new_argv[1] = padding;
 130
 131                 for(i = 2; i <= argc; i++)
 132                         new_argv[i] = argv[i - 1];
 133                 new_argv[argc + 1] = NULL;
 134
 135                 execvp(new_argv[0], new_argv);
 136                 perror("execing with extended args");
 137                 exit(1);
 138         }
 139 #endif
 140
 141         linux_prog = argv[0];
 142
 143         set_stklim();
 144
 145         setup_env_path();
 146
 147         new_argv = malloc((argc + 1) * sizeof(char *));
 148         if(new_argv == NULL){
 149                 perror("Mallocing argv");
 150                 exit(1);
 151         }
 152         for(i=0;i<argc;i++){
 153                 new_argv[i] = strdup(argv[i]);
 154                 if(new_argv[i] == NULL){
 155                         perror("Mallocing an arg");
 156                         exit(1);
 157                 }
 158         }
 159         new_argv[argc] = NULL;
 160
 161         set_handler(SIGINT, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 162         set_handler(SIGTERM, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 163         set_handler(SIGHUP, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 164
 165         scan_elf_aux( envp);
 166
 167         do_uml_initcalls();
 168         ret = linux_main(argc, argv);
 169
 170         /* Disable SIGPROF - I have no idea why libc doesn't do this or turn
 171          * off the profiling time, but UML dies with a SIGPROF just before
 172          * exiting when profiling is active.
 173          */
 174         change_sig(SIGPROF, 0);
 175
 176         /* This signal stuff used to be in the reboot case.  However,
 177          * sometimes a SIGVTALRM can come in when we're halting (reproducably
 178          * when writing out gcov information, presumably because that takes
 179          * some time) and cause a segfault.
 180          */
 181
 182         /* stop timers and set SIG*ALRM to be ignored */
 183         disable_timer();
 184
 185         /* disable SIGIO for the fds and set SIGIO to be ignored */
 186         err = deactivate_all_fds();
 187         if(err)
 188                 printf("deactivate_all_fds failed, errno = %d\n", -err);
 189
 190         /* Let any pending signals fire now.  This ensures
 191          * that they won't be delivered after the exec, when
 192          * they are definitely not expected.
 193          */
 194         unblock_signals();
 195
 196         /* Reboot */
 197         if(ret){
 198                 printf("\n");
 199                 execvp(new_argv[0], new_argv);
 200                 perror("Failed to exec kernel");
 201                 ret = 1;
 202         }
 203         printf("\n");
 204         return(uml_exitcode);
 205 }
 206
 207 #define CAN_KMALLOC() \
 208         (kmalloc_ok && CHOOSE_MODE((os_getpid() != tracing_pid), 1))
 209
 210 extern void *__real_malloc(int);
 211
 212 void *__wrap_malloc(int size)
 213 {
 214         void *ret;
 215
 216         if(!CAN_KMALLOC())
 217                 return(__real_malloc(size));
 218         else if(size <= PAGE_SIZE) /* finding contiguos pages can be hard*/
 219                 ret = um_kmalloc(size);
 220         else ret = um_vmalloc(size);
 221
 222         /* glibc people insist that if malloc fails, errno should be
 223          * set by malloc as well. So we do.
 224          */
 225         if(ret == NULL)
 226                 errno = ENOMEM;
 227
 228         return(ret);
 229 }
 230
 231 void *__wrap_calloc(int n, int size)
 232 {
 233         void *ptr = __wrap_malloc(n * size);
 234
 235         if(ptr == NULL) return(NULL);
 236         memset(ptr, 0, n * size);
 237         return(ptr);
 238 }
 239
 240 extern void __real_free(void *);
 241
 242 extern unsigned long high_physmem;
 243
 244 void __wrap_free(void *ptr)
 245 {
 246         unsigned long addr = (unsigned long) ptr;
 247
 248         /* We need to know how the allocation happened, so it can be correctly
 249          * freed.  This is done by seeing what region of memory the pointer is
 250          * in -
 251          *      physical memory - kmalloc/kfree
 252          *      kernel virtual memory - vmalloc/vfree
 253          *      anywhere else - malloc/free
 254          * If kmalloc is not yet possible, then either high_physmem and/or
 255          * end_vm are still 0 (as at startup), in which case we call free, or
 256          * we have set them, but anyway addr has not been allocated from those
 257          * areas. So, in both cases __real_free is called.
 258          *
 259          * CAN_KMALLOC is checked because it would be bad to free a buffer
 260          * with kmalloc/vmalloc after they have been turned off during
 261          * shutdown.
 262          * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
 263          * there is a possibility for memory leaks.
 264          */
 265
 266         if((addr >= uml_physmem) && (addr < high_physmem)){
 267                 if(CAN_KMALLOC())
 268                         kfree(ptr);
 269         }
 270         else if((addr >= start_vm) && (addr < end_vm)){
 271                 if(CAN_KMALLOC())
 272                         vfree(ptr);
 273         }
 274         else __real_free(ptr);
 275 }