[PATCH] uml: move libc-dependent startup and signal code
The serial UML OS-abstraction layer patch (um/kernel dir).
This moves all systemcalls from process.c file under os-Linux dir and join
process.c and process_kern.c files.
Signed-off-by: Gennady Sharapov <gennady.v.sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
new file mode 100644
index 0000000..a3eab25
--- /dev/null
+++ b/arch/um/os-Linux/start_up.c
@@ -0,0 +1,329 @@
+/*
+ * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sched.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <sys/mman.h>
+#include <asm/unistd.h>
+#include <asm/page.h>
+#include "user_util.h"
+#include "kern_util.h"
+#include "user.h"
+#include "signal_kern.h"
+#include "signal_user.h"
+#include "sysdep/ptrace.h"
+#include "sysdep/sigcontext.h"
+#include "irq_user.h"
+#include "ptrace_user.h"
+#include "time_user.h"
+#include "init.h"
+#include "os.h"
+#include "uml-config.h"
+#include "choose-mode.h"
+#include "mode.h"
+#include "tempfile.h"
+#ifdef UML_CONFIG_MODE_SKAS
+#include "skas.h"
+#include "skas_ptrace.h"
+#include "registers.h"
+#endif
+
+static int ptrace_child(void *arg)
+{
+ int ret;
+ int pid = os_getpid(), ppid = getppid();
+ int sc_result;
+
+ if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
+ perror("ptrace");
+ os_kill_process(pid, 0);
+ }
+ os_stop_process(pid);
+
+ /*This syscall will be intercepted by the parent. Don't call more than
+ * once, please.*/
+ sc_result = os_getpid();
+
+ if (sc_result == pid)
+ ret = 1; /*Nothing modified by the parent, we are running
+ normally.*/
+ else if (sc_result == ppid)
+ ret = 0; /*Expected in check_ptrace and check_sysemu when they
+ succeed in modifying the stack frame*/
+ else
+ ret = 2; /*Serious trouble! This could be caused by a bug in
+ host 2.6 SKAS3/2.6 patch before release -V6, together
+ with a bug in the UML code itself.*/
+ _exit(ret);
+}
+
+static int start_ptraced_child(void **stack_out)
+{
+ void *stack;
+ unsigned long sp;
+ int pid, n, status;
+
+ stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if(stack == MAP_FAILED)
+ panic("check_ptrace : mmap failed, errno = %d", errno);
+ sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
+ pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
+ if(pid < 0)
+ panic("start_ptraced_child : clone failed, errno = %d", errno);
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ if(n < 0)
+ panic("check_ptrace : clone failed, errno = %d", errno);
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
+ panic("check_ptrace : expected SIGSTOP, got status = %d",
+ status);
+
+ *stack_out = stack;
+ return(pid);
+}
+
+/* When testing for SYSEMU support, if it is one of the broken versions, we
+ * must just avoid using sysemu, not panic, but only if SYSEMU features are
+ * broken.
+ * So only for SYSEMU features we test mustpanic, while normal host features
+ * must work anyway!
+ */
+static int stop_ptraced_child(int pid, void *stack, int exitcode,
+ int mustpanic)
+{
+ int status, n, ret = 0;
+
+ if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
+ panic("check_ptrace : ptrace failed, errno = %d", errno);
+ CATCH_EINTR(n = waitpid(pid, &status, 0));
+ if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
+ int exit_with = WEXITSTATUS(status);
+ if (exit_with == 2)
+ printk("check_ptrace : child exited with status 2. "
+ "Serious trouble happening! Try updating your "
+ "host skas patch!\nDisabling SYSEMU support.");
+ printk("check_ptrace : child exited with exitcode %d, while "
+ "expecting %d; status 0x%x", exit_with,
+ exitcode, status);
+ if (mustpanic)
+ panic("\n");
+ else
+ printk("\n");
+ ret = -1;
+ }
+
+ if(munmap(stack, PAGE_SIZE) < 0)
+ panic("check_ptrace : munmap failed, errno = %d", errno);
+ return ret;
+}
+
+int ptrace_faultinfo = 1;
+int proc_mm = 1;
+
+static int __init skas0_cmd_param(char *str, int* add)
+{
+ ptrace_faultinfo = proc_mm = 0;
+ return 0;
+}
+
+__uml_setup("skas0", skas0_cmd_param,
+ "skas0\n"
+ " Disables SKAS3 usage, so that SKAS0 is used, unless \n"
+ " you specify mode=tt.\n\n");
+
+static int force_sysemu_disabled = 0;
+
+static int __init nosysemu_cmd_param(char *str, int* add)
+{
+ force_sysemu_disabled = 1;
+ return 0;
+}
+
+__uml_setup("nosysemu", nosysemu_cmd_param,
+"nosysemu\n"
+" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
+" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
+" behaviour of ptrace() and helps reducing host context switch rate.\n"
+" To make it working, you need a kernel patch for your host, too.\n"
+" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
+" information.\n\n");
+
+static void __init check_sysemu(void)
+{
+ void *stack;
+ int pid, syscall, n, status, count=0;
+
+ printk("Checking syscall emulation patch for ptrace...");
+ sysemu_supported = 0;
+ pid = start_ptraced_child(&stack);
+
+ if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
+ goto fail;
+
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ if (n < 0)
+ panic("check_sysemu : wait failed, errno = %d", errno);
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+ panic("check_sysemu : expected SIGTRAP, "
+ "got status = %d", status);
+
+ n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
+ os_getpid());
+ if(n < 0)
+ panic("check_sysemu : failed to modify system "
+ "call return, errno = %d", errno);
+
+ if (stop_ptraced_child(pid, stack, 0, 0) < 0)
+ goto fail_stopped;
+
+ sysemu_supported = 1;
+ printk("OK\n");
+ set_using_sysemu(!force_sysemu_disabled);
+
+ printk("Checking advanced syscall emulation patch for ptrace...");
+ pid = start_ptraced_child(&stack);
+ while(1){
+ count++;
+ if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
+ goto fail;
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ if(n < 0)
+ panic("check_ptrace : wait failed, errno = %d", errno);
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+ panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
+ "got status = %d", status);
+
+ syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
+ 0);
+ if(syscall == __NR_getpid){
+ if (!count)
+ panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
+ n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
+ os_getpid());
+ if(n < 0)
+ panic("check_sysemu : failed to modify system "
+ "call return, errno = %d", errno);
+ break;
+ }
+ }
+ if (stop_ptraced_child(pid, stack, 0, 0) < 0)
+ goto fail_stopped;
+
+ sysemu_supported = 2;
+ printk("OK\n");
+
+ if ( !force_sysemu_disabled )
+ set_using_sysemu(sysemu_supported);
+ return;
+
+fail:
+ stop_ptraced_child(pid, stack, 1, 0);
+fail_stopped:
+ printk("missing\n");
+}
+
+static void __init check_ptrace(void)
+{
+ void *stack;
+ int pid, syscall, n, status;
+
+ printk("Checking that ptrace can change system call numbers...");
+ pid = start_ptraced_child(&stack);
+
+ if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
+ panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", errno);
+
+ while(1){
+ if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
+ panic("check_ptrace : ptrace failed, errno = %d",
+ errno);
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ if(n < 0)
+ panic("check_ptrace : wait failed, errno = %d", errno);
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80))
+ panic("check_ptrace : expected SIGTRAP + 0x80, "
+ "got status = %d", status);
+
+ syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
+ 0);
+ if(syscall == __NR_getpid){
+ n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
+ __NR_getppid);
+ if(n < 0)
+ panic("check_ptrace : failed to modify system "
+ "call, errno = %d", errno);
+ break;
+ }
+ }
+ stop_ptraced_child(pid, stack, 0, 1);
+ printk("OK\n");
+ check_sysemu();
+}
+
+void os_early_checks(void)
+{
+ check_ptrace();
+}
+
+#ifdef UML_CONFIG_MODE_SKAS
+static inline void check_skas3_ptrace_support(void)
+{
+ struct ptrace_faultinfo fi;
+ void *stack;
+ int pid, n;
+
+ printf("Checking for the skas3 patch in the host...");
+ pid = start_ptraced_child(&stack);
+
+ n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
+ if (n < 0) {
+ ptrace_faultinfo = 0;
+ if(errno == EIO)
+ printf("not found\n");
+ else
+ perror("not found");
+ }
+ else {
+ if (!ptrace_faultinfo)
+ printf("found but disabled on command line\n");
+ else
+ printf("found\n");
+ }
+
+ init_registers(pid);
+ stop_ptraced_child(pid, stack, 1, 1);
+}
+
+int can_do_skas(void)
+{
+ printf("Checking for /proc/mm...");
+ if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
+ proc_mm = 0;
+ printf("not found\n");
+ }
+ else {
+ if (!proc_mm)
+ printf("found but disabled on command line\n");
+ else
+ printf("found\n");
+ }
+
+ check_skas3_ptrace_support();
+ return 1;
+}
+#else
+int can_do_skas(void)
+{
+ return(0);
+}
+#endif