From: Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>
Fix some bugs left in the failure path of run_helper by the previous patch:
it was missing one
os_close_file(fds[1])
which is conditional. To use the goto handling model, I set the fd to -1
if it's already closed (I don't want to check if keeping one more pipe-end
open is no problem).
Also do some cosmethic cleanup:
* "err" was what we returned even on success, so just use a neutral "ret".
* use tabs, not spaces.
* a little more comments.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/um/drivers/net_user.c | 3 +-
25-akpm/arch/um/kernel/helper.c | 48 ++++++++++++++++++++-----------------
2 files changed, 29 insertions(+), 22 deletions(-)
diff -puN arch/um/drivers/net_user.c~uml-finish-fixing-run_helper-failure-path arch/um/drivers/net_user.c
--- 25/arch/um/drivers/net_user.c~uml-finish-fixing-run_helper-failure-path Tue Nov 30 15:20:36 2004
+++ 25-akpm/arch/um/drivers/net_user.c Tue Nov 30 15:20:36 2004
@@ -177,7 +177,8 @@ static int change_tramp(char **argv, cha
os_close_file(fds[0]);
os_close_file(fds[1]);
- CATCH_EINTR(err = waitpid(pid, NULL, 0));
+ if (pid > 0)
+ CATCH_EINTR(err = waitpid(pid, NULL, 0));
return(pid);
}
diff -puN arch/um/kernel/helper.c~uml-finish-fixing-run_helper-failure-path arch/um/kernel/helper.c
--- 25/arch/um/kernel/helper.c~uml-finish-fixing-run_helper-failure-path Tue Nov 30 15:20:36 2004
+++ 25-akpm/arch/um/kernel/helper.c Tue Nov 30 15:20:36 2004
@@ -49,14 +49,14 @@ static int helper_child(void *arg)
return(0);
}
-/* XXX The alloc_stack here breaks if this is called in the tracing thread */
-
+/* 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], err, n;
+ int pid, fds[2], ret, n;
if((stack_out != NULL) && (*stack_out != 0))
stack = *stack_out;
@@ -64,16 +64,16 @@ int run_helper(void (*pre_exec)(void *),
if(stack == 0)
return(-ENOMEM);
- err = os_pipe(fds, 1, 0);
- if(err < 0){
- printk("run_helper : pipe failed, err = %d\n", -err);
+ ret = os_pipe(fds, 1, 0);
+ if(ret < 0){
+ printk("run_helper : pipe failed, ret = %d\n", -ret);
goto out_free;
}
- err = os_set_exec_close(fds[1], 1);
- if(err < 0){
- printk("run_helper : setting FD_CLOEXEC failed, err = %d\n",
- -err);
+ 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;
}
@@ -85,30 +85,36 @@ int run_helper(void (*pre_exec)(void *),
pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
if(pid < 0){
printk("run_helper : clone failed, errno = %d\n", errno);
- err = -errno;
+ ret = -errno;
goto out_close;
}
os_close_file(fds[1]);
- n = os_read_file(fds[0], &err, sizeof(err));
+ 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, err = %d\n", -n);
- err = n;
+ printk("run_helper : read on pipe failed, ret = %d\n", -n);
+ ret = n;
os_kill_process(pid, 1);
}
else if(n != 0){
CATCH_EINTR(n = waitpid(pid, NULL, 0));
- pid = -errno;
+ ret = -errno;
+ } else {
+ ret = pid;
}
- err = pid;
- out_close:
+out_close:
+ if (fds[1] != -1)
+ os_close_file(fds[1]);
os_close_file(fds[0]);
- out_free:
+out_free:
if(stack_out == NULL)
free_stack(stack, 0);
- else *stack_out = stack;
- return(err);
+ else *stack_out = stack;
+ return(ret);
}
int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
@@ -139,7 +145,7 @@ int run_helper_thread(int (*proc)(void *
"0x%x\n", status);
free_stack(stack, stack_order);
}
- else *stack_out = stack;
+ else *stack_out = stack;
return(pid);
}
_