uml: miscellaneous code cleanups - openslx/kernel-qcow2-linux.git

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author	Jeff Dike	2008-02-05 07:31:04 +0100
committer	Linus Torvalds	2008-02-05 18:44:29 +0100
commit	bf8fde785b872282e7e86d9ea8a9c4e543985bb3 (patch)
tree	cb813edfbb04c8474caab0f8a26a8512a503cf82 /arch/um/os-Linux/start_up.c
parent	uml: fix mconsole stop (diff)
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uml: miscellaneous code cleanups

Code tidying - the pid field of struct irq_fd isn't used, so it is removed os_set_fd_async needed to read flags before changing them, it doesn't need a pid passed in because it can call getpid itself, and a block of unused code needed deleting os_get_exec_close was unused, so it is removed ptrace_child called _exit for historical reasons which are no longer valid, so just calls exit instead Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Diffstat (limited to 'arch/um/os-Linux/start_up.c')

-rw-r--r--

arch/um/os-Linux/start_up.c

1 files changed, 2 insertions, 1 deletions

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/* * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com) * Licensed under the GPL */ #include <pty.h> #include <stdio.h> #include <stddef.h> #include <stdarg.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <signal.h> #include <sched.h> #include <fcntl.h> #include <errno.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 <sys/types.h> #include "user_util.h" #include "kern_util.h" #include "user.h" #include "signal_kern.h" #include "sysdep/ptrace.h" #include "sysdep/sigcontext.h" #include "irq_user.h" #include "ptrace_user.h" #include "mem_user.h" #include "init.h" #include "os.h" #include "uml-config.h" #include "choose-mode.h" #include "mode.h" #include "tempfile.h" #include "kern_constants.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; change_sig(SIGWINCH, 0); 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) printf("check_ptrace : child exited with status 2. " "Serious trouble happening! Try updating your " "host skas patch!\nDisabling SYSEMU support."); printf("check_ptrace : child exited with exitcode %d, while " "expecting %d; status 0x%x", exit_with, exitcode, status); if (mustpanic) panic("\n"); else printf("\n"); ret = -1; } if(munmap(stack, PAGE_SIZE) < 0) panic("check_ptrace : munmap failed, errno = %d", errno); return ret; } int ptrace_faultinfo = 1; int ptrace_ldt = 1; int proc_mm = 1; int skas_needs_stub = 0; static int __init skas0_cmd_param(char *str, int* add) { ptrace_faultinfo = proc_mm = 0; return 0; } /* The two __uml_setup would conflict, without this stupid alias. */ static int __init mode_skas0_cmd_param(char *str, int* add) __attribute__((alias("skas0_cmd_param"))); __uml_setup("skas0", skas0_cmd_param, "skas0\n" " Disables SKAS3 usage, so that SKAS0 is used, unless \n" " you specify mode=tt.\n\n"); __uml_setup("mode=skas0", mode_skas0_cmd_param, "mode=skas0\n" " Disables SKAS3 usage, so that SKAS0 is used, unless you \n" " specify mode=tt. Note that this was recently added - on \n" " older kernels you must use simply \"skas0\".\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, n, status, count=0; printf("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);


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