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: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -25,7 +25,7 @@
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#include "registers.h"
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#include "skas_ptrace.h"
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static int ptrace_child(void *arg)
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static int ptrace_child(void)
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{
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int ret;
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int pid = os_getpid(), ppid = getppid();
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@ -90,31 +90,23 @@ static void non_fatal(char *fmt, ...)
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fflush(stdout);
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}
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static int start_ptraced_child(void **stack_out)
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static int start_ptraced_child(void)
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{
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void *stack;
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unsigned long sp;
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int pid, n, status;
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stack = mmap(NULL, UM_KERN_PAGE_SIZE,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (stack == MAP_FAILED)
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fatal_perror("check_ptrace : mmap failed");
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sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
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pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
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if (pid < 0)
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fatal_perror("start_ptraced_child : clone failed");
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pid = fork();
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if (pid == 0)
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ptrace_child();
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else if (pid < 0)
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fatal_perror("start_ptraced_child : fork failed");
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CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
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if (n < 0)
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fatal_perror("check_ptrace : clone failed");
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fatal_perror("check_ptrace : waitpid failed");
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if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
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fatal("check_ptrace : expected SIGSTOP, got status = %d",
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status);
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*stack_out = stack;
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return pid;
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}
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@ -124,8 +116,7 @@ static int start_ptraced_child(void **stack_out)
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* So only for SYSEMU features we test mustpanic, while normal host features
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* must work anyway!
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*/
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static int stop_ptraced_child(int pid, void *stack, int exitcode,
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int mustexit)
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static int stop_ptraced_child(int pid, int exitcode, int mustexit)
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{
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int status, n, ret = 0;
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@ -145,8 +136,6 @@ static int stop_ptraced_child(int pid, void *stack, int exitcode,
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ret = -1;
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}
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if (munmap(stack, UM_KERN_PAGE_SIZE) < 0)
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fatal_perror("check_ptrace : munmap failed");
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return ret;
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}
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@ -198,13 +187,12 @@ __uml_setup("nosysemu", nosysemu_cmd_param,
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static void __init check_sysemu(void)
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{
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void *stack;
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unsigned long regs[MAX_REG_NR];
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int pid, n, status, count=0;
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non_fatal("Checking syscall emulation patch for ptrace...");
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sysemu_supported = 0;
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pid = start_ptraced_child(&stack);
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pid = start_ptraced_child();
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if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
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goto fail;
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@ -231,7 +219,7 @@ static void __init check_sysemu(void)
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goto fail;
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}
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if (stop_ptraced_child(pid, stack, 0, 0) < 0)
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if (stop_ptraced_child(pid, 0, 0) < 0)
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goto fail_stopped;
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sysemu_supported = 1;
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@ -239,7 +227,7 @@ static void __init check_sysemu(void)
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set_using_sysemu(!force_sysemu_disabled);
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non_fatal("Checking advanced syscall emulation patch for ptrace...");
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pid = start_ptraced_child(&stack);
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pid = start_ptraced_child();
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if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
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(void *) PTRACE_O_TRACESYSGOOD) < 0))
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@ -271,7 +259,7 @@ static void __init check_sysemu(void)
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fatal("check_ptrace : expected SIGTRAP or "
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"(SIGTRAP | 0x80), got status = %d", status);
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}
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if (stop_ptraced_child(pid, stack, 0, 0) < 0)
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if (stop_ptraced_child(pid, 0, 0) < 0)
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goto fail_stopped;
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sysemu_supported = 2;
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@ -282,18 +270,17 @@ static void __init check_sysemu(void)
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return;
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fail:
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stop_ptraced_child(pid, stack, 1, 0);
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stop_ptraced_child(pid, 1, 0);
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fail_stopped:
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non_fatal("missing\n");
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}
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static void __init check_ptrace(void)
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{
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void *stack;
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int pid, syscall, n, status;
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non_fatal("Checking that ptrace can change system call numbers...");
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pid = start_ptraced_child(&stack);
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pid = start_ptraced_child();
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if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
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(void *) PTRACE_O_TRACESYSGOOD) < 0))
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@ -323,7 +310,7 @@ static void __init check_ptrace(void)
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break;
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}
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}
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stop_ptraced_child(pid, stack, 0, 1);
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stop_ptraced_child(pid, 0, 1);
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non_fatal("OK\n");
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check_sysemu();
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}
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@ -403,11 +390,10 @@ __uml_setup("noptraceldt", noptraceldt_cmd_param,
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static inline void check_skas3_ptrace_faultinfo(void)
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{
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struct ptrace_faultinfo fi;
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void *stack;
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int pid, n;
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non_fatal(" - PTRACE_FAULTINFO...");
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pid = start_ptraced_child(&stack);
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pid = start_ptraced_child();
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n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
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if (n < 0) {
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@ -425,13 +411,12 @@ static inline void check_skas3_ptrace_faultinfo(void)
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}
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init_registers(pid);
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stop_ptraced_child(pid, stack, 1, 1);
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stop_ptraced_child(pid, 1, 1);
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}
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static inline void check_skas3_ptrace_ldt(void)
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{
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#ifdef PTRACE_LDT
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void *stack;
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int pid, n;
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unsigned char ldtbuf[40];
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struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
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@ -440,7 +425,7 @@ static inline void check_skas3_ptrace_ldt(void)
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.bytecount = sizeof(ldtbuf)};
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non_fatal(" - PTRACE_LDT...");
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pid = start_ptraced_child(&stack);
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pid = start_ptraced_child();
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n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
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if (n < 0) {
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@ -458,7 +443,7 @@ static inline void check_skas3_ptrace_ldt(void)
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non_fatal("found, but use is disabled\n");
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}
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stop_ptraced_child(pid, stack, 1, 1);
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stop_ptraced_child(pid, 1, 1);
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#else
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/* PTRACE_LDT might be disabled via cmdline option.
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* We want to override this, else we might use the stub
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