uml: tidy helper code

Style fixes to arch/um/os/helper.c and tidying up the breakpoint fix a
bit.

helper.c gets all the usual style fixes -
	 updated copyright
	 all printks get severities

Also -
	 errval changes to err in helper_child
	 fixed an obsolete comment
	 run_helper was killing a child process which is guaranteed to
be dead or dying anyway

Removed the nohang and pname arguments from helper_wait and fixed the
declaration and callers.  nohang was used only in the slirp driver and
I don't think it was needed.  I think pname was a bit of overkill in
putting out an error message when something goes wrong.

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>

3 files changed, 32 insertions, 46 deletions

diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index 07ca0cb472ac..6fb0b174f538 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -131,7 +131,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
         }
         if (c != 1) {
                 printk(UM_KERN_ERR "etap_tramp : uml_net failed\n");
-                err = helper_wait(pid, 0, "uml_net");
+                err = helper_wait(pid);
         }
         return err;
 }
diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c
index 7739e29cf341..2448be03fd7a 100644
--- a/arch/um/os-Linux/drivers/tuntap_user.c
+++ b/arch/um/os-Linux/drivers/tuntap_user.c
@@ -108,7 +108,7 @@ static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
                        "errno = %d\n", errno);
                 return err;
         }
-        helper_wait(pid, 0, "tuntap_open_tramp");
+        helper_wait(pid);
 
         cmsg = CMSG_FIRSTHDR(&msg);
         if (cmsg == NULL) {
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index fba3f0fefeef..f4bd349d4412 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -1,22 +1,19 @@
 /*
- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
-#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
 #include <sched.h>
-#include <limits.h>
-#include <sys/signal.h>
-#include <sys/wait.h>
 #include <sys/socket.h>
-#include "user.h"
+#include <sys/wait.h>
+#include "kern_constants.h"
 #include "kern_util.h"
 #include "os.h"
 #include "um_malloc.h"
-#include "kern_constants.h"
+#include "user.h"
 
 struct helper_data {
         void (*pre_exec)(void*);
@@ -30,21 +27,19 @@ static int helper_child(void *arg)
 {
         struct helper_data *data = arg;
         char **argv = data->argv;
-        int errval;
+        int err;
 
         if (data->pre_exec != NULL)
                 (*data->pre_exec)(data->pre_data);
-        errval = execvp_noalloc(data->buf, argv[0], argv);
-        printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0],
-               -errval);
-        write(data->fd, &errval, sizeof(errval));
-        kill(os_getpid(), SIGKILL);
+        err = execvp_noalloc(data->buf, argv[0], argv);
+
+        /* If the exec succeeds, we don't get here */
+        write(data->fd, &err, sizeof(err));
+
         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, so
- * we need to receive a preallocated stack (a local buffer is ok). */
+/* Returns either the pid of the child process we run or -E* on failure. */
 int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
 {
         struct helper_data data;
@@ -58,14 +53,15 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
         ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
         if (ret < 0) {
                 ret = -errno;
-                printk("run_helper : pipe failed, errno = %d\n", errno);
+                printk(UM_KERN_ERR "run_helper : pipe failed, errno = %d\n",
+                       errno);
                 goto out_free;
         }
 
         ret = os_set_exec_close(fds[1]);
         if (ret < 0) {
-                printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n",
-                       -ret);
+                printk(UM_KERN_ERR "run_helper : setting FD_CLOEXEC failed, "
+                       "ret = %d\n", -ret);
                 goto out_close;
         }
 
@@ -79,7 +75,8 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
         pid = clone(helper_child, (void *) sp, CLONE_VM, &data);
         if (pid < 0) {
                 ret = -errno;
-                printk("run_helper : clone failed, errno = %d\n", errno);
+                printk(UM_KERN_ERR "run_helper : clone failed, errno = %d\n",
+                       errno);
                 goto out_free2;
         }
 
@@ -96,10 +93,9 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
         } else {
                 if (n < 0) {
                         n = -errno;
-                        printk("run_helper : read on pipe failed, ret = %d\n",
-                               -n);
+                        printk(UM_KERN_ERR "run_helper : read on pipe failed, "
+                               "ret = %d\n", -n);
                         ret = n;
-                        kill(pid, SIGKILL);
                 }
                 CATCH_EINTR(waitpid(pid, NULL, __WCLONE));
         }
@@ -129,50 +125,40 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
         pid = clone(proc, (void *) sp, flags, arg);
         if (pid < 0) {
                 err = -errno;
-                printk("run_helper_thread : clone failed, errno = %d\n",
-                       errno);
+                printk(UM_KERN_ERR "run_helper_thread : clone failed, "
+                       "errno = %d\n", errno);
                 return err;
         }
         if (stack_out == NULL) {
                 CATCH_EINTR(pid = waitpid(pid, &status, __WCLONE));
                 if (pid < 0) {
                         err = -errno;
-                        printk("run_helper_thread - wait failed, errno = %d\n",
-                               errno);
+                        printk(UM_KERN_ERR "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);
+                        printk(UM_KERN_ERR "run_helper_thread - thread "
+                               "returned status 0x%x\n", status);
                 free_stack(stack, 0);
         } else
                 *stack_out = stack;
         return pid;
 }
 
-int helper_wait(int pid, int nohang, char *pname)
+int helper_wait(int pid)
 {
         int ret, status;
         int wflags = __WCLONE;
 
-        if (nohang)
-                wflags |= WNOHANG;
-
-        if (!pname)
-                pname = "helper_wait";
-
         CATCH_EINTR(ret = waitpid(pid, &status, wflags));
         if (ret < 0) {
-                printk(UM_KERN_ERR "%s : waitpid process %d failed, "
-                       "errno = %d\n", pname, pid, errno);
+                printk(UM_KERN_ERR "helper_wait : waitpid process %d failed, "
+                       "errno = %d\n", pid, errno);
                 return -errno;
-        } else if (nohang && ret == 0) {
-                printk(UM_KERN_ERR "%s : process %d has not exited\n",
-                       pname, pid);
-                return -ECHILD;
         } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-                printk(UM_KERN_ERR "%s : process %d didn't exit with "
-                       "status 0\n", pname, pid);
+                printk(UM_KERN_ERR "helper_wait : process %d exited with "
+                       "status 0x%x\n", pid, status);
                 return -ECHILD;
         } else
                 return 0;