212 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			212 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
#
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# Minimalist mconsole exec patch 
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#
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# 3.10 version (with bit more synchronous behavior) by fingon at iki dot fi
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# Adaptation to kernel 3.3.8 made by David Fernández (david at dit.upm.es) for 
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# Starting point: mconsole-exec-2.6.30.patch for kernel 2.6.30
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# Author of original patch: Paolo Giarrusso, aka Blaisorblade 
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#                           (http://www.user-mode-linux.org/~blaisorblade)
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#
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# Known misfeatures:
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#
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# - If output is too long, blocks (and breaks horribly) 
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# (this misfeature from 3.10 patches, when minimalizing the patch;
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#  workaround: redirect to a shared filesystem if long output is expected)
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#
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# - Nothing useful is done with stdin
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#
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--- a/arch/um/drivers/mconsole.h
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+++ b/arch/um/drivers/mconsole.h
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@@ -85,6 +85,7 @@ extern void mconsole_cad(struct mc_reque
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 extern void mconsole_stop(struct mc_request *req);
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 extern void mconsole_go(struct mc_request *req);
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 extern void mconsole_log(struct mc_request *req);
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+extern void mconsole_exec(struct mc_request *req);
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 extern void mconsole_proc(struct mc_request *req);
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 extern void mconsole_stack(struct mc_request *req);
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--- a/arch/um/drivers/mconsole_kern.c
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+++ b/arch/um/drivers/mconsole_kern.c
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@@ -4,6 +4,7 @@
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  * Licensed under the GPL
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  */
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+#include "linux/kmod.h"
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 #include <linux/console.h>
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 #include <linux/ctype.h>
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 #include <linux/string.h>
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@@ -24,6 +25,7 @@
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 #include <linux/fs.h>
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 #include <linux/mount.h>
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 #include <linux/file.h>
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+#include <linux/completion.h>
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 #include <asm/uaccess.h>
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 #include <asm/switch_to.h>
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@@ -121,6 +123,59 @@ void mconsole_log(struct mc_request *req
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 	mconsole_reply(req, "", 0, 0);
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 }
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+void mconsole_exec(struct mc_request *req)
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+{
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+  struct subprocess_info *sub_info;
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+  int res, len;
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+  struct file *out;
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+  char buf[MCONSOLE_MAX_DATA];
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+
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+  char *envp[] = {
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+    "HOME=/", "TERM=linux",
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+    "PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin",
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+    NULL
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+  };
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+  char *argv[] = {
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+    "/bin/sh", "-c",
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+    req->request.data + strlen("exec "),
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+    NULL
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+  };
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+
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+  sub_info = call_usermodehelper_setup("/bin/sh", argv, envp, GFP_ATOMIC, NULL, NULL, NULL);
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+  if (sub_info == NULL) {
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+    mconsole_reply(req, "call_usermodehelper_setup failed", 1, 0);
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+    return;
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+  }
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+  res = call_usermodehelper_stdoutpipe(sub_info, &out);
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+  if (res < 0) {
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+    kfree(sub_info);
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+    mconsole_reply(req, "call_usermodehelper_stdoutpipe failed", 1, 0);
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+    return;
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+  }
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+
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+  res = call_usermodehelper_exec(sub_info, UMH_WAIT_PROC);
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+  if (res < 0) {
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+    kfree(sub_info);
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+    mconsole_reply(req, "call_usermodehelper_exec failed", 1, 0);
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+    return;
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+  }
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+
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+  for (;;) {
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+    len = out->f_op->read(out, buf, sizeof(buf), &out->f_pos);
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+    if (len < 0) {
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+      mconsole_reply(req, "reading output failed", 1, 0);
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+      break;
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+    }
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+    if (len == 0)
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+      break;
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+    mconsole_reply_len(req, buf, len, 0, 1);
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+  }
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+  fput(out);
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+
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+  mconsole_reply_len(req, NULL, 0, 0, 0);
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+}
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+
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+
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 void mconsole_proc(struct mc_request *req)
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 {
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 	struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
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@@ -187,6 +242,7 @@ void mconsole_proc(struct mc_request *re
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     stop - pause the UML; it will do nothing until it receives a 'go' \n\
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     go - continue the UML after a 'stop' \n\
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     log <string> - make UML enter <string> into the kernel log\n\
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+    exec <string> - pass <string> to /bin/sh -c synchronously\n\
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     proc <file> - returns the contents of the UML's /proc/<file>\n\
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     stack <pid> - returns the stack of the specified pid\n\
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 "
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--- a/arch/um/drivers/mconsole_user.c
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+++ b/arch/um/drivers/mconsole_user.c
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@@ -30,6 +30,7 @@ static struct mconsole_command commands[
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 	{ "stop", mconsole_stop, MCONSOLE_PROC },
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 	{ "go", mconsole_go, MCONSOLE_INTR },
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 	{ "log", mconsole_log, MCONSOLE_INTR },
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+	{ "exec", mconsole_exec, MCONSOLE_PROC },
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 	{ "proc", mconsole_proc, MCONSOLE_PROC },
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 	{ "stack", mconsole_stack, MCONSOLE_INTR },
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 };
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--- a/arch/um/os-Linux/file.c
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+++ b/arch/um/os-Linux/file.c
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@@ -534,6 +534,8 @@ int os_create_unix_socket(const char *fi
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 	addr.sun_family = AF_UNIX;
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+	if (len > sizeof(addr.sun_path))
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+		len = sizeof(addr.sun_path);
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 	snprintf(addr.sun_path, len, "%s", file);
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 	err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
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--- a/include/linux/kmod.h
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+++ b/include/linux/kmod.h
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@@ -62,6 +62,7 @@ struct subprocess_info {
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 	int wait;
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 	int retval;
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 	int (*init)(struct subprocess_info *info, struct cred *new);
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+	struct file *stdout;
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 	void (*cleanup)(struct subprocess_info *info);
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 	void *data;
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 };
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@@ -104,4 +105,6 @@ extern int usermodehelper_read_trylock(v
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 extern long usermodehelper_read_lock_wait(long timeout);
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 extern void usermodehelper_read_unlock(void);
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+int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info, struct file **filp);
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+
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 #endif /* __LINUX_KMOD_H__ */
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--- a/kernel/kmod.c
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+++ b/kernel/kmod.c
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@@ -39,6 +39,7 @@
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 #include <linux/rwsem.h>
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 #include <linux/ptrace.h>
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 #include <linux/async.h>
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+#include <linux/pipe_fs_i.h>
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 #include <asm/uaccess.h>
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 #include <trace/events/module.h>
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@@ -231,6 +232,28 @@ static int ____call_usermodehelper(void
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 	flush_signal_handlers(current, 1);
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 	spin_unlock_irq(¤t->sighand->siglock);
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+        /* Install output when needed */
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+        if (sub_info->stdout) {
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+                struct files_struct *f = current->files;
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+                struct fdtable *fdt;
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+
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+                sys_close(1);
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+                sys_close(2);
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+                get_file(sub_info->stdout);
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+                fd_install(1, sub_info->stdout);
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+                fd_install(2, sub_info->stdout);
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+                spin_lock(&f->file_lock);
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+                fdt = files_fdtable(f);
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+                __set_bit(1, fdt->open_fds);
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+                __clear_bit(1, fdt->close_on_exec);
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+                __set_bit(2, fdt->open_fds);
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+                __clear_bit(2, fdt->close_on_exec);
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+                spin_unlock(&f->file_lock);
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+
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+                /* disallow core files */
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+                current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0};
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+        }
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+
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 	/* We can run anywhere, unlike our parent keventd(). */
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 	set_cpus_allowed_ptr(current, cpu_all_mask);
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@@ -544,6 +567,20 @@ struct subprocess_info *call_usermodehel
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 }
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 EXPORT_SYMBOL(call_usermodehelper_setup);
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+int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info,
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+                                 struct file **filp)
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+{
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+  struct file *f[2];
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+
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+  if (create_pipe_files(f, 0)<0)
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+    return PTR_ERR(f);
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+  sub_info->stdout = f[1];
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+  *filp = f[0];
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+  return 0;
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+}
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+EXPORT_SYMBOL(call_usermodehelper_stdoutpipe);
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+
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+
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 /**
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  * call_usermodehelper_exec - start a usermode application
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  * @sub_info: information about the subprocessa
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