1 files changed, 254 insertions, 0 deletions
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
new file mode 100644
index 000000000..c8a42ecbd
--- /dev/null
+++ b/arch/um/os-Linux/main.c
@@ -0,0 +1,254 @@
+// 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();
+
+	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);
+}