main.c 6.7 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297
  1. /*
  2. * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
  3. * Licensed under the GPL
  4. */
  5. #include <unistd.h>
  6. #include <stdio.h>
  7. #include <stdlib.h>
  8. #include <string.h>
  9. #include <signal.h>
  10. #include <errno.h>
  11. #include <sys/resource.h>
  12. #include <sys/mman.h>
  13. #include <sys/user.h>
  14. #include <asm/page.h>
  15. #include "user_util.h"
  16. #include "kern_util.h"
  17. #include "mem_user.h"
  18. #include "irq_user.h"
  19. #include "user.h"
  20. #include "init.h"
  21. #include "mode.h"
  22. #include "choose-mode.h"
  23. #include "uml-config.h"
  24. #include "os.h"
  25. /* Set in set_stklim, which is called from main and __wrap_malloc.
  26. * __wrap_malloc only calls it if main hasn't started.
  27. */
  28. unsigned long stacksizelim;
  29. /* Set in main */
  30. char *linux_prog;
  31. #define PGD_BOUND (4 * 1024 * 1024)
  32. #define STACKSIZE (8 * 1024 * 1024)
  33. #define THREAD_NAME_LEN (256)
  34. static void set_stklim(void)
  35. {
  36. struct rlimit lim;
  37. if(getrlimit(RLIMIT_STACK, &lim) < 0){
  38. perror("getrlimit");
  39. exit(1);
  40. }
  41. if((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)){
  42. lim.rlim_cur = STACKSIZE;
  43. if(setrlimit(RLIMIT_STACK, &lim) < 0){
  44. perror("setrlimit");
  45. exit(1);
  46. }
  47. }
  48. stacksizelim = (lim.rlim_cur + PGD_BOUND - 1) & ~(PGD_BOUND - 1);
  49. }
  50. static __init void do_uml_initcalls(void)
  51. {
  52. initcall_t *call;
  53. call = &__uml_initcall_start;
  54. while (call < &__uml_initcall_end){
  55. (*call)();
  56. call++;
  57. }
  58. }
  59. static void last_ditch_exit(int sig)
  60. {
  61. uml_cleanup();
  62. exit(1);
  63. }
  64. static void install_fatal_handler(int sig)
  65. {
  66. struct sigaction action;
  67. /* All signals are enabled in this handler ... */
  68. sigemptyset(&action.sa_mask);
  69. /* ... including the signal being handled, plus we want the
  70. * handler reset to the default behavior, so that if an exit
  71. * handler is hanging for some reason, the UML will just die
  72. * after this signal is sent a second time.
  73. */
  74. action.sa_flags = SA_RESETHAND | SA_NODEFER;
  75. action.sa_restorer = NULL;
  76. action.sa_handler = last_ditch_exit;
  77. if(sigaction(sig, &action, NULL) < 0){
  78. printf("failed to install handler for signal %d - errno = %d\n",
  79. errno);
  80. exit(1);
  81. }
  82. }
  83. #define UML_LIB_PATH ":/usr/lib/uml"
  84. static void setup_env_path(void)
  85. {
  86. char *new_path = NULL;
  87. char *old_path = NULL;
  88. int path_len = 0;
  89. old_path = getenv("PATH");
  90. /* if no PATH variable is set or it has an empty value
  91. * just use the default + /usr/lib/uml
  92. */
  93. if (!old_path || (path_len = strlen(old_path)) == 0) {
  94. putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH);
  95. return;
  96. }
  97. /* append /usr/lib/uml to the existing path */
  98. path_len += strlen("PATH=" UML_LIB_PATH) + 1;
  99. new_path = malloc(path_len);
  100. if (!new_path) {
  101. perror("coudn't malloc to set a new PATH");
  102. return;
  103. }
  104. snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path);
  105. putenv(new_path);
  106. }
  107. extern int uml_exitcode;
  108. extern void scan_elf_aux( char **envp);
  109. int main(int argc, char **argv, char **envp)
  110. {
  111. char **new_argv;
  112. int ret, i, err;
  113. #ifdef UML_CONFIG_CMDLINE_ON_HOST
  114. /* Allocate memory for thread command lines */
  115. if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){
  116. char padding[THREAD_NAME_LEN] = {
  117. [ 0 ... THREAD_NAME_LEN - 2] = ' ', '\0'
  118. };
  119. new_argv = malloc((argc + 2) * sizeof(char*));
  120. if(!new_argv) {
  121. perror("Allocating extended argv");
  122. exit(1);
  123. }
  124. new_argv[0] = argv[0];
  125. new_argv[1] = padding;
  126. for(i = 2; i <= argc; i++)
  127. new_argv[i] = argv[i - 1];
  128. new_argv[argc + 1] = NULL;
  129. execvp(new_argv[0], new_argv);
  130. perror("execing with extended args");
  131. exit(1);
  132. }
  133. #endif
  134. linux_prog = argv[0];
  135. set_stklim();
  136. setup_env_path();
  137. new_argv = malloc((argc + 1) * sizeof(char *));
  138. if(new_argv == NULL){
  139. perror("Mallocing argv");
  140. exit(1);
  141. }
  142. for(i=0;i<argc;i++){
  143. new_argv[i] = strdup(argv[i]);
  144. if(new_argv[i] == NULL){
  145. perror("Mallocing an arg");
  146. exit(1);
  147. }
  148. }
  149. new_argv[argc] = NULL;
  150. /* Allow these signals to bring down a UML if all other
  151. * methods of control fail.
  152. */
  153. install_fatal_handler(SIGINT);
  154. install_fatal_handler(SIGTERM);
  155. install_fatal_handler(SIGHUP);
  156. scan_elf_aux( envp);
  157. do_uml_initcalls();
  158. ret = linux_main(argc, argv);
  159. /* Disable SIGPROF - I have no idea why libc doesn't do this or turn
  160. * off the profiling time, but UML dies with a SIGPROF just before
  161. * exiting when profiling is active.
  162. */
  163. change_sig(SIGPROF, 0);
  164. /* This signal stuff used to be in the reboot case. However,
  165. * sometimes a SIGVTALRM can come in when we're halting (reproducably
  166. * when writing out gcov information, presumably because that takes
  167. * some time) and cause a segfault.
  168. */
  169. /* stop timers and set SIG*ALRM to be ignored */
  170. disable_timer();
  171. /* disable SIGIO for the fds and set SIGIO to be ignored */
  172. err = deactivate_all_fds();
  173. if(err)
  174. printf("deactivate_all_fds failed, errno = %d\n", -err);
  175. /* Let any pending signals fire now. This ensures
  176. * that they won't be delivered after the exec, when
  177. * they are definitely not expected.
  178. */
  179. unblock_signals();
  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. #define CAN_KMALLOC() \
  191. (kmalloc_ok && CHOOSE_MODE((os_getpid() != tracing_pid), 1))
  192. extern void *__real_malloc(int);
  193. void *__wrap_malloc(int size)
  194. {
  195. void *ret;
  196. if(!CAN_KMALLOC())
  197. return(__real_malloc(size));
  198. else if(size <= PAGE_SIZE) /* finding contiguos pages can be hard*/
  199. ret = um_kmalloc(size);
  200. else ret = um_vmalloc(size);
  201. /* glibc people insist that if malloc fails, errno should be
  202. * set by malloc as well. So we do.
  203. */
  204. if(ret == NULL)
  205. errno = ENOMEM;
  206. return(ret);
  207. }
  208. void *__wrap_calloc(int n, int size)
  209. {
  210. void *ptr = __wrap_malloc(n * size);
  211. if(ptr == NULL) return(NULL);
  212. memset(ptr, 0, n * size);
  213. return(ptr);
  214. }
  215. extern void __real_free(void *);
  216. extern unsigned long high_physmem;
  217. void __wrap_free(void *ptr)
  218. {
  219. unsigned long addr = (unsigned long) ptr;
  220. /* We need to know how the allocation happened, so it can be correctly
  221. * freed. This is done by seeing what region of memory the pointer is
  222. * in -
  223. * physical memory - kmalloc/kfree
  224. * kernel virtual memory - vmalloc/vfree
  225. * anywhere else - malloc/free
  226. * If kmalloc is not yet possible, then either high_physmem and/or
  227. * end_vm are still 0 (as at startup), in which case we call free, or
  228. * we have set them, but anyway addr has not been allocated from those
  229. * areas. So, in both cases __real_free is called.
  230. *
  231. * CAN_KMALLOC is checked because it would be bad to free a buffer
  232. * with kmalloc/vmalloc after they have been turned off during
  233. * shutdown.
  234. * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
  235. * there is a possibility for memory leaks.
  236. */
  237. if((addr >= uml_physmem) && (addr < high_physmem)){
  238. if(CAN_KMALLOC())
  239. kfree(ptr);
  240. }
  241. else if((addr >= start_vm) && (addr < end_vm)){
  242. if(CAN_KMALLOC())
  243. vfree(ptr);
  244. }
  245. else __real_free(ptr);
  246. }