| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) |
| * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <signal.h> |
| #include <string.h> |
| #include <sys/resource.h> |
| #include <as-layout.h> |
| #include <init.h> |
| #include <kern_util.h> |
| #include <os.h> |
| #include <um_malloc.h> |
| |
| #define PGD_BOUND (4 * 1024 * 1024) |
| #define STACKSIZE (8 * 1024 * 1024) |
| #define THREAD_NAME_LEN (256) |
| |
| long elf_aux_hwcap; |
| |
| static void set_stklim(void) |
| { |
| struct rlimit lim; |
| |
| if (getrlimit(RLIMIT_STACK, &lim) < 0) { |
| perror("getrlimit"); |
| exit(1); |
| } |
| if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) { |
| lim.rlim_cur = STACKSIZE; |
| if (setrlimit(RLIMIT_STACK, &lim) < 0) { |
| perror("setrlimit"); |
| exit(1); |
| } |
| } |
| } |
| |
| static void last_ditch_exit(int sig) |
| { |
| uml_cleanup(); |
| exit(1); |
| } |
| |
| static void install_fatal_handler(int sig) |
| { |
| struct sigaction action; |
| |
| /* All signals are enabled in this handler ... */ |
| sigemptyset(&action.sa_mask); |
| |
| /* |
| * ... including the signal being handled, plus we want the |
| * handler reset to the default behavior, so that if an exit |
| * handler is hanging for some reason, the UML will just die |
| * after this signal is sent a second time. |
| */ |
| action.sa_flags = SA_RESETHAND | SA_NODEFER; |
| action.sa_restorer = NULL; |
| action.sa_handler = last_ditch_exit; |
| if (sigaction(sig, &action, NULL) < 0) { |
| os_warn("failed to install handler for signal %d " |
| "- errno = %d\n", sig, errno); |
| exit(1); |
| } |
| } |
| |
| #define UML_LIB_PATH ":" OS_LIB_PATH "/uml" |
| |
| static void setup_env_path(void) |
| { |
| char *new_path = NULL; |
| char *old_path = NULL; |
| int path_len = 0; |
| |
| old_path = getenv("PATH"); |
| /* |
| * if no PATH variable is set or it has an empty value |
| * just use the default + /usr/lib/uml |
| */ |
| if (!old_path || (path_len = strlen(old_path)) == 0) { |
| if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH)) |
| perror("couldn't putenv"); |
| return; |
| } |
| |
| /* append /usr/lib/uml to the existing path */ |
| path_len += strlen("PATH=" UML_LIB_PATH) + 1; |
| new_path = malloc(path_len); |
| if (!new_path) { |
| perror("couldn't malloc to set a new PATH"); |
| return; |
| } |
| snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path); |
| if (putenv(new_path)) { |
| perror("couldn't putenv to set a new PATH"); |
| free(new_path); |
| } |
| } |
| |
| extern void scan_elf_aux( char **envp); |
| |
| int __init main(int argc, char **argv, char **envp) |
| { |
| char **new_argv; |
| int ret, i, err; |
| |
| set_stklim(); |
| |
| setup_env_path(); |
| |
| setsid(); |
| |
| new_argv = malloc((argc + 1) * sizeof(char *)); |
| if (new_argv == NULL) { |
| perror("Mallocing argv"); |
| exit(1); |
| } |
| for (i = 0; i < argc; i++) { |
| new_argv[i] = strdup(argv[i]); |
| if (new_argv[i] == NULL) { |
| perror("Mallocing an arg"); |
| exit(1); |
| } |
| } |
| new_argv[argc] = NULL; |
| |
| /* |
| * Allow these signals to bring down a UML if all other |
| * methods of control fail. |
| */ |
| install_fatal_handler(SIGINT); |
| install_fatal_handler(SIGTERM); |
| |
| #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA |
| scan_elf_aux(envp); |
| #endif |
| |
| change_sig(SIGPIPE, 0); |
| ret = linux_main(argc, argv); |
| |
| /* |
| * Disable SIGPROF - I have no idea why libc doesn't do this or turn |
| * off the profiling time, but UML dies with a SIGPROF just before |
| * exiting when profiling is active. |
| */ |
| change_sig(SIGPROF, 0); |
| |
| /* |
| * This signal stuff used to be in the reboot case. However, |
| * sometimes a timer signal can come in when we're halting (reproducably |
| * when writing out gcov information, presumably because that takes |
| * some time) and cause a segfault. |
| */ |
| |
| /* stop timers and set timer signal to be ignored */ |
| os_timer_disable(); |
| |
| /* disable SIGIO for the fds and set SIGIO to be ignored */ |
| err = deactivate_all_fds(); |
| if (err) |
| os_warn("deactivate_all_fds failed, errno = %d\n", -err); |
| |
| /* |
| * Let any pending signals fire now. This ensures |
| * that they won't be delivered after the exec, when |
| * they are definitely not expected. |
| */ |
| unblock_signals_trace(); |
| |
| os_info("\n"); |
| /* Reboot */ |
| if (ret) { |
| execvp(new_argv[0], new_argv); |
| perror("Failed to exec kernel"); |
| ret = 1; |
| } |
| return uml_exitcode; |
| } |
| |
| extern void *__real_malloc(int); |
| |
| void *__wrap_malloc(int size) |
| { |
| void *ret; |
| |
| if (!kmalloc_ok) |
| return __real_malloc(size); |
| else if (size <= UM_KERN_PAGE_SIZE) |
| /* finding contiguous pages can be hard*/ |
| ret = uml_kmalloc(size, UM_GFP_KERNEL); |
| else ret = vmalloc(size); |
| |
| /* |
| * glibc people insist that if malloc fails, errno should be |
| * set by malloc as well. So we do. |
| */ |
| if (ret == NULL) |
| errno = ENOMEM; |
| |
| return ret; |
| } |
| |
| void *__wrap_calloc(int n, int size) |
| { |
| void *ptr = __wrap_malloc(n * size); |
| |
| if (ptr == NULL) |
| return NULL; |
| memset(ptr, 0, n * size); |
| return ptr; |
| } |
| |
| extern void __real_free(void *); |
| |
| extern unsigned long high_physmem; |
| |
| void __wrap_free(void *ptr) |
| { |
| unsigned long addr = (unsigned long) ptr; |
| |
| /* |
| * We need to know how the allocation happened, so it can be correctly |
| * freed. This is done by seeing what region of memory the pointer is |
| * in - |
| * physical memory - kmalloc/kfree |
| * kernel virtual memory - vmalloc/vfree |
| * anywhere else - malloc/free |
| * If kmalloc is not yet possible, then either high_physmem and/or |
| * end_vm are still 0 (as at startup), in which case we call free, or |
| * we have set them, but anyway addr has not been allocated from those |
| * areas. So, in both cases __real_free is called. |
| * |
| * CAN_KMALLOC is checked because it would be bad to free a buffer |
| * with kmalloc/vmalloc after they have been turned off during |
| * shutdown. |
| * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so |
| * there is a possibility for memory leaks. |
| */ |
| |
| if ((addr >= uml_physmem) && (addr < high_physmem)) { |
| if (kmalloc_ok) |
| kfree(ptr); |
| } |
| else if ((addr >= start_vm) && (addr < end_vm)) { |
| if (kmalloc_ok) |
| vfree(ptr); |
| } |
| else __real_free(ptr); |
| } |