// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) */ #include <stdarg.h>#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <errno.h>#include <signal.h>#include <string.h>#include <termios.h>#include <sys/wait.h>#include <sys/mman.h>#include <sys/utsname.h>#include <sys/random.h>#include <init.h>#include <os.h> void stack_protections(unsigned long address){	if (mprotect((void *) address, UM_THREAD_SIZE, PROT_READ | PROT_WRITE) < 0)		panic("protecting stack failed, errno = %d", errno);} int raw(int fd){	struct termios tt;	int err; 	CATCH_EINTR(err = tcgetattr(fd, &tt));	if (err < 0)		return -errno; 	cfmakeraw(&tt); 	CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt));	if (err < 0)		return -errno; 	/*	 * XXX tcsetattr could have applied only some changes	 * (and cfmakeraw() is a set of changes)	 */	return 0;} void setup_machinename(char *machine_out){	struct utsname host; 	uname(&host);#if IS_ENABLED(CONFIG_UML_X86)# if !IS_ENABLED(CONFIG_64BIT)	if (!strcmp(host.machine, "x86_64")) {		strcpy(machine_out, "i686");		return;	}# else	if (!strcmp(host.machine, "i686")) {		strcpy(machine_out, "x86_64");		return;	}# endif#endif	strcpy(machine_out, host.machine);} void setup_hostinfo(char *buf, int len){	struct utsname host; 	uname(&host);	snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename,		 host.release, host.version, host.machine);} /* * We cannot use glibc's abort(). It makes use of tgkill() which * has no effect within UML's kernel threads. * After that glibc would execute an invalid instruction to kill * the calling process and UML crashes with SIGSEGV. */static inline void __attribute__ ((noreturn)) uml_abort(void){	sigset_t sig; 	fflush(NULL); 	if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT))		sigprocmask(SIG_UNBLOCK, &sig, 0); 	for (;;)		if (kill(getpid(), SIGABRT) < 0)			exit(127);} ssize_t os_getrandom(void *buf, size_t len, unsigned int flags){	return getrandom(buf, len, flags);} /* * UML helper threads must not handle SIGWINCH/INT/TERM */void os_fix_helper_signals(void){	signal(SIGWINCH, SIG_IGN);	signal(SIGINT, SIG_DFL);	signal(SIGTERM, SIG_DFL);} void os_dump_core(void){	int pid; 	signal(SIGSEGV, SIG_DFL); 	/*	 * We are about to SIGTERM this entire process group to ensure that	 * nothing is around to run after the kernel exits.  The	 * kernel wants to abort, not die through SIGTERM, so we	 * ignore it here.	 */ 	signal(SIGTERM, SIG_IGN);	kill(0, SIGTERM);	/*	 * Most of the other processes associated with this UML are	 * likely sTopped, so give them a SIGCONT so they see the	 * SIGTERM.	 */	kill(0, SIGCONT); 	/*	 * Now, having sent signals to everyone but us, make sure they	 * die by ptrace.  Processes can survive what's been done to	 * them so far - the mechanism I understand is receiving a	 * SIGSEGV and segfaulting immediately upon return.  There is	 * always a SIGSEGV pending, and (I'm guessing) signals are	 * processed in numeric order so the SIGTERM (signal 15 vs	 * SIGSEGV being signal 11) is never handled.	 *	 * Run a waitpid loop until we get some kind of error.	 * Hopefully, it's ECHILD, but there's not a lot we can do if	 * it's something else.  Tell os_kill_ptraced_process not to	 * wait for the child to report its death because there's	 * nothing reasonable to do if that fails.	 */ 	while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)		os_kill_ptraced_process(pid, 0); 	uml_abort();} void um_early_printk(const char *s, unsigned int n){	printf("%.*s", n, s);} static int quiet_info; static int __init quiet_cmd_param(char *str, int *add){	quiet_info = 1;	return 0;} __uml_setup("quiet", quiet_cmd_param,"quiet\n""    Turns off information messages during boot.\n\n"); /* * The os_info/os_warn functions will be called by helper threads. These * have a very limited stack size and using the libc formatting functions * may overflow the stack. * So pull in the kernel vscnprintf and use that instead with a fixed * on-stack buffer. */int vscnprintf(char *buf, size_t size, const char *fmt, va_list args); void os_info(const char *fmt, ...){	char buf[256];	va_list list;	int len; 	if (quiet_info)		return; 	va_start(list, fmt);	len = vscnprintf(buf, sizeof(buf), fmt, list);	fwrite(buf, len, 1, stderr);	va_end(list);} void os_warn(const char *fmt, ...){	char buf[256];	va_list list;	int len; 	va_start(list, fmt);	len = vscnprintf(buf, sizeof(buf), fmt, list);	fwrite(buf, len, 1, stderr);	va_end(list);}