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Commit 3cdaf455 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: replace clone with fork 



Convert the boot-time host ptrace testing from clone to fork.  They were
essentially doing fork anyway.  This cleans up the code a bit, and makes
valgrind a bit happier about grinding it.

Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8ca842c4

arch/um/os-Linux/start_up.c

+20 −35
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ 
#include "registers.h"

#include "skas_ptrace.h"



static int ptrace_child(void *arg)

static int ptrace_child(void)

{

	int ret;

	int pid = os_getpid(), ppid = getppid();
@@ -90,31 +90,23 @@ static void non_fatal(char *fmt, ...) 
	fflush(stdout);

}



static int start_ptraced_child(void **stack_out)

static int start_ptraced_child(void)

{

	void *stack;

	unsigned long sp;

	int pid, n, status;



	stack = mmap(NULL, UM_KERN_PAGE_SIZE,

		     PROT_READ | PROT_WRITE | PROT_EXEC,

		     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

	if (stack == MAP_FAILED)

		fatal_perror("check_ptrace : mmap failed");



	sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);

	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);

	if (pid < 0)

		fatal_perror("start_ptraced_child : clone failed");

	pid = fork();

	if (pid == 0)

		ptrace_child();

	else if (pid < 0)

		fatal_perror("start_ptraced_child : fork failed");



	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));

	if (n < 0)

		fatal_perror("check_ptrace : clone failed");

		fatal_perror("check_ptrace : waitpid failed");

	if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))

		fatal("check_ptrace : expected SIGSTOP, got status = %d",

		      status);



	*stack_out = stack;

	return pid;

}
@@ -124,8 +116,7 @@ static int start_ptraced_child(void **stack_out) 
 * 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 mustexit)

static int stop_ptraced_child(int pid, int exitcode, int mustexit)

{

	int status, n, ret = 0;
@@ -145,8 +136,6 @@ static int stop_ptraced_child(int pid, void *stack, int exitcode, 
		ret = -1;

	}



	if (munmap(stack, UM_KERN_PAGE_SIZE) < 0)

		fatal_perror("check_ptrace : munmap failed");

	return ret;

}
@@ -198,13 +187,12 @@ __uml_setup("nosysemu", nosysemu_cmd_param, 


static void __init check_sysemu(void)

{

	void *stack;

	unsigned long regs[MAX_REG_NR];

	int pid, n, status, count=0;



	non_fatal("Checking syscall emulation patch for ptrace...");

	sysemu_supported = 0;

	pid = start_ptraced_child(&stack);

	pid = start_ptraced_child();



	if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)

		goto fail;
@@ -231,7 +219,7 @@ static void __init check_sysemu(void) 
		goto fail;

	}



	if (stop_ptraced_child(pid, stack, 0, 0) < 0)

	if (stop_ptraced_child(pid, 0, 0) < 0)

		goto fail_stopped;



	sysemu_supported = 1;
@@ -239,7 +227,7 @@ static void __init check_sysemu(void) 
	set_using_sysemu(!force_sysemu_disabled);



	non_fatal("Checking advanced syscall emulation patch for ptrace...");

	pid = start_ptraced_child(&stack);

	pid = start_ptraced_child();



	if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,

		   (void *) PTRACE_O_TRACESYSGOOD) < 0))
@@ -271,7 +259,7 @@ static void __init check_sysemu(void) 
			fatal("check_ptrace : expected SIGTRAP or "

			      "(SIGTRAP | 0x80), got status = %d", status);

	}

	if (stop_ptraced_child(pid, stack, 0, 0) < 0)

	if (stop_ptraced_child(pid, 0, 0) < 0)

		goto fail_stopped;



	sysemu_supported = 2;
@@ -282,18 +270,17 @@ static void __init check_sysemu(void) 
	return;



fail:

	stop_ptraced_child(pid, stack, 1, 0);

	stop_ptraced_child(pid, 1, 0);

fail_stopped:

	non_fatal("missing\n");

}



static void __init check_ptrace(void)

{

	void *stack;

	int pid, syscall, n, status;



	non_fatal("Checking that ptrace can change system call numbers...");

	pid = start_ptraced_child(&stack);

	pid = start_ptraced_child();



	if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,

		   (void *) PTRACE_O_TRACESYSGOOD) < 0))
@@ -323,7 +310,7 @@ static void __init check_ptrace(void) 
			break;

		}

	}

	stop_ptraced_child(pid, stack, 0, 1);

	stop_ptraced_child(pid, 0, 1);

	non_fatal("OK\n");

	check_sysemu();

}
@@ -403,11 +390,10 @@ __uml_setup("noptraceldt", noptraceldt_cmd_param, 
static inline void check_skas3_ptrace_faultinfo(void)

{

	struct ptrace_faultinfo fi;

	void *stack;

	int pid, n;



	non_fatal("  - PTRACE_FAULTINFO...");

	pid = start_ptraced_child(&stack);

	pid = start_ptraced_child();



	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);

	if (n < 0) {
@@ -425,13 +411,12 @@ static inline void check_skas3_ptrace_faultinfo(void) 
	}



	init_registers(pid);

	stop_ptraced_child(pid, stack, 1, 1);

	stop_ptraced_child(pid, 1, 1);

}



static inline void check_skas3_ptrace_ldt(void)

{

#ifdef PTRACE_LDT

	void *stack;

	int pid, n;

	unsigned char ldtbuf[40];

	struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
@@ -440,7 +425,7 @@ static inline void check_skas3_ptrace_ldt(void) 
		.bytecount = sizeof(ldtbuf)};



	non_fatal("  - PTRACE_LDT...");

	pid = start_ptraced_child(&stack);

	pid = start_ptraced_child();



	n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);

	if (n < 0) {
@@ -458,7 +443,7 @@ static inline void check_skas3_ptrace_ldt(void) 
			non_fatal("found, but use is disabled\n");

	}



	stop_ptraced_child(pid, stack, 1, 1);

	stop_ptraced_child(pid, 1, 1);

#else

	/* PTRACE_LDT might be disabled via cmdline option.

	 * We want to override this, else we might use the stub