[PATCH 1/6] UML - tidy helper code

From: Jeff Dike
Date: Wed Dec 12 2007 - 15:50:40 EST

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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@xxxxxxxxxxxxxxx>
---
arch/um/drivers/net_user.c | 2
arch/um/drivers/slip_user.c | 2
arch/um/drivers/slirp_user.c | 2
arch/um/include/os.h | 2
arch/um/os-Linux/drivers/ethertap_user.c | 2
arch/um/os-Linux/drivers/tuntap_user.c | 2
arch/um/os-Linux/helper.c | 74 ++++++++++++-------------------
7 files changed, 36 insertions(+), 50 deletions(-)

Index: linux-2.6-git/arch/um/os-Linux/helper.c
===================================================================
--- linux-2.6-git.orig/arch/um/os-Linux/helper.c 2007-12-12 14:10:34.000000000 -0500
+++ linux-2.6-git/arch/um/os-Linux/helper.c 2007-12-12 14:10:44.000000000 -0500
@@ -1,22 +1,19 @@
/*
- * Copyright (C) 2002 Jeff Dike (jdike@xxxxxxxxxx)
+ * 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 *),
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 *),
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 *),
} 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 *
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;
Index: linux-2.6-git/arch/um/drivers/net_user.c
===================================================================
--- linux-2.6-git.orig/arch/um/drivers/net_user.c 2007-12-12 14:10:35.000000000 -0500
+++ linux-2.6-git/arch/um/drivers/net_user.c 2007-12-12 14:10:44.000000000 -0500
@@ -201,7 +201,7 @@ static int change_tramp(char **argv, cha
close(fds[1]);

if (pid > 0)
- helper_wait(pid, 0, "change_tramp");
+ helper_wait(pid);
return pid;
}

Index: linux-2.6-git/arch/um/drivers/slip_user.c
===================================================================
--- linux-2.6-git.orig/arch/um/drivers/slip_user.c 2007-12-12 14:10:35.000000000 -0500
+++ linux-2.6-git/arch/um/drivers/slip_user.c 2007-12-12 14:10:44.000000000 -0500
@@ -109,7 +109,7 @@ static int slip_tramp(char **argv, int f
read_output(fds[0], output, output_len);
printk("%s", output);

- err = helper_wait(pid, 0, argv[0]);
+ err = helper_wait(pid);
close(fds[0]);

out_free:
Index: linux-2.6-git/arch/um/drivers/slirp_user.c
===================================================================
--- linux-2.6-git.orig/arch/um/drivers/slirp_user.c 2007-12-12 14:10:35.000000000 -0500
+++ linux-2.6-git/arch/um/drivers/slirp_user.c 2007-12-12 14:10:44.000000000 -0500
@@ -98,7 +98,7 @@ static void slirp_close(int fd, void *da
"(%d)\n", pri->pid, errno);
}
#endif
- err = helper_wait(pri->pid, 1, "slirp_close");
+ err = helper_wait(pri->pid);
if (err < 0)
return;

Index: linux-2.6-git/arch/um/os-Linux/drivers/ethertap_user.c
===================================================================
--- linux-2.6-git.orig/arch/um/os-Linux/drivers/ethertap_user.c 2007-12-12 14:10:35.000000000 -0500
+++ linux-2.6-git/arch/um/os-Linux/drivers/ethertap_user.c 2007-12-12 14:10:44.000000000 -0500
@@ -131,7 +131,7 @@ static int etap_tramp(char *dev, char *g
}
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;
}
Index: linux-2.6-git/arch/um/os-Linux/drivers/tuntap_user.c
===================================================================
--- linux-2.6-git.orig/arch/um/os-Linux/drivers/tuntap_user.c 2007-12-12 14:10:35.000000000 -0500
+++ linux-2.6-git/arch/um/os-Linux/drivers/tuntap_user.c 2007-12-12 14:10:44.000000000 -0500
@@ -108,7 +108,7 @@ static int tuntap_open_tramp(char *gate,
"errno = %d\n", errno);
return err;
}
- helper_wait(pid, 0, "tuntap_open_tramp");
+ helper_wait(pid);

cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg == NULL) {
Index: linux-2.6-git/arch/um/include/os.h
===================================================================
--- linux-2.6-git.orig/arch/um/include/os.h 2007-12-12 14:10:35.000000000 -0500
+++ linux-2.6-git/arch/um/include/os.h 2007-12-12 15:06:13.000000000 -0500
@@ -207,7 +207,7 @@ extern int execvp_noalloc(char *buf, con
extern int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv);
extern int run_helper_thread(int (*proc)(void *), void *arg,
unsigned int flags, unsigned long *stack_out);
-extern int helper_wait(int pid, int nohang, char *pname);
+extern int helper_wait(int pid);

/* tls.c */
--
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Next message: Jeff Dike: "[PATCH 3/6] UML - Get rid of syscall counters"
Previous message: Jeff Dike: "[PATCH 5/6] UML - Move sig_handler_common_skas"
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