diff options
| -rw-r--r-- | arch/um/os-Linux/start_up.c | 55 |
1 files changed, 20 insertions, 35 deletions
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c index f22715868929..c5c36dbe819b 100644 --- a/arch/um/os-Linux/start_up.c +++ b/arch/um/os-Linux/start_up.c @@ -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 |