1 files changed, 165 insertions, 0 deletions

diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
new file mode 100644
index 000000000000..36cc8475bcda
--- /dev/null
+++ b/arch/um/os-Linux/helper.c
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sched.h>
+#include <sys/signal.h>
+#include <sys/wait.h>
+#include "user.h"
+#include "kern_util.h"
+#include "user_util.h"
+#include "os.h"
+
+struct helper_data {
+        void (*pre_exec)(void*);
+        void *pre_data;
+        char **argv;
+        int fd;
+};
+
+/* Debugging aid, changed only from gdb */
+int helper_pause = 0;
+
+static void helper_hup(int sig)
+{
+}
+
+static int helper_child(void *arg)
+{
+        struct helper_data *data = arg;
+        char **argv = data->argv;
+        int errval;
+
+        if(helper_pause){
+                signal(SIGHUP, helper_hup);
+                pause();
+        }
+        if(data->pre_exec != NULL)
+                (*data->pre_exec)(data->pre_data);
+        execvp(argv[0], argv);
+        errval = errno;
+        printk("execvp of '%s' failed - errno = %d\n", argv[0], errno);
+        os_write_file(data->fd, &errval, sizeof(errval));
+        kill(os_getpid(), SIGKILL);
+        return(0);
+}
+
+/* Returns either the pid of the child process we run or -E* on failure.
+ * XXX The alloc_stack here breaks if this is called in the tracing thread */
+int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
+               unsigned long *stack_out)
+{
+        struct helper_data data;
+        unsigned long stack, sp;
+        int pid, fds[2], ret, n;
+
+        if((stack_out != NULL) && (*stack_out != 0))
+                stack = *stack_out;
+        else stack = alloc_stack(0, um_in_interrupt());
+        if(stack == 0)
+                return(-ENOMEM);
+
+        ret = os_pipe(fds, 1, 0);
+        if(ret < 0){
+                printk("run_helper : pipe failed, ret = %d\n", -ret);
+                goto out_free;
+        }
+
+        ret = os_set_exec_close(fds[1], 1);
+        if(ret < 0){
+                printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n",
+                       -ret);
+                goto out_close;
+        }
+
+        sp = stack + page_size() - sizeof(void *);
+        data.pre_exec = pre_exec;
+        data.pre_data = pre_data;
+        data.argv = argv;
+        data.fd = fds[1];
+        pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
+        if(pid < 0){
+                ret = -errno;
+                printk("run_helper : clone failed, errno = %d\n", errno);
+                goto out_close;
+        }
+
+        close(fds[1]);
+        fds[1] = -1;
+
+        /*Read the errno value from the child.*/
+        n = os_read_file(fds[0], &ret, sizeof(ret));
+        if(n < 0){
+                printk("run_helper : read on pipe failed, ret = %d\n", -n);
+                ret = n;
+                kill(pid, SIGKILL);
+                CATCH_EINTR(waitpid(pid, NULL, 0));
+        }
+        else if(n != 0){
+                CATCH_EINTR(n = waitpid(pid, NULL, 0));
+                ret = -errno;
+        } else {
+                ret = pid;
+        }
+
+out_close:
+        if (fds[1] != -1)
+                close(fds[1]);
+        close(fds[0]);
+out_free:
+        if(stack_out == NULL)
+                free_stack(stack, 0);
+        else *stack_out = stack;
+        return(ret);
+}
+
+int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
+                      unsigned long *stack_out, int stack_order)
+{
+        unsigned long stack, sp;
+        int pid, status, err;
+
+        stack = alloc_stack(stack_order, um_in_interrupt());
+        if(stack == 0) return(-ENOMEM);
+
+        sp = stack + (page_size() << stack_order) - sizeof(void *);
+        pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
+        if(pid < 0){
+                err = -errno;
+                printk("run_helper_thread : clone failed, errno = %d\n",
+                       errno);
+                return err;
+        }
+        if(stack_out == NULL){
+                CATCH_EINTR(pid = waitpid(pid, &status, 0));
+                if(pid < 0){
+                        err = -errno;
+                        printk("run_helper_thread - wait failed, errno = %d\n",
+                               errno);
+                        pid = err;
+                }
+                if(!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
+                        printk("run_helper_thread - thread returned status "
+                               "0x%x\n", status);
+                free_stack(stack, stack_order);
+        }
+        else *stack_out = stack;
+        return(pid);
+}
+
+int helper_wait(int pid)
+{
+        int ret;
+
+        CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG));
+        if(ret < 0){
+                ret = -errno;
+                printk("helper_wait : waitpid failed, errno = %d\n", errno);
+        }
+        return(ret);
+}