1 files changed, 34 insertions, 122 deletions

diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 51069245b79..29880c9b324 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -21,15 +21,19 @@
 #include <linux/un.h>
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/file.h>
 #include <asm/uaccess.h>
+#include <asm/switch_to.h>
 
-#include "init.h"
-#include "irq_kern.h"
-#include "irq_user.h"
-#include "kern_util.h"
+#include <init.h>
+#include <irq_kern.h>
+#include <irq_user.h>
+#include <kern_util.h>
 #include "mconsole.h"
 #include "mconsole_kern.h"
-#include "os.h"
+#include <os.h>
 
 static int do_unlink_socket(struct notifier_block *notifier,
 			    unsigned long what, void *data)
@@ -117,120 +121,38 @@ void mconsole_log(struct mc_request *req)
 	mconsole_reply(req, "", 0, 0);
 }
 
-/* This is a more convoluted version of mconsole_proc, which has some stability
- * problems; however, we need it fixed, because it is expected that UML users
- * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
- * show the real procfs content, not the ones from hppfs.*/
-#if 0
 void mconsole_proc(struct mc_request *req)
 {
-	struct nameidata nd;
-	struct file_system_type *proc;
-	struct super_block *super;
-	struct file *file;
-	int n, err;
-	char *ptr = req->request.data, *buf;
-
-	ptr += strlen("proc");
-	ptr = skip_spaces(ptr);
-
-	proc = get_fs_type("proc");
-	if (proc == NULL) {
-		mconsole_reply(req, "procfs not registered", 1, 0);
-		goto out;
-	}
-
-	super = (*proc->get_sb)(proc, 0, NULL, NULL);
-	put_filesystem(proc);
-	if (super == NULL) {
-		mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
-		goto out;
-	}
-	up_write(&super->s_umount);
-
-	nd.path.dentry = super->s_root;
-	nd.path.mnt = NULL;
-	nd.flags = O_RDONLY + 1;
-	nd.last_type = LAST_ROOT;
-
-	/* START: it was experienced that the stability problems are closed
-	 * if commenting out these two calls + the below read cycle. To
-	 * make UML crash again, it was enough to readd either one.*/
-	err = link_path_walk(ptr, &nd);
-	if (err) {
-		mconsole_reply(req, "Failed to look up file", 1, 0);
-		goto out_kill;
-	}
-
-	file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
-			   current_cred());
-	if (IS_ERR(file)) {
-		mconsole_reply(req, "Failed to open file", 1, 0);
-		goto out_kill;
-	}
-	/*END*/
-
-	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-	if (buf == NULL) {
-		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
-		goto out_fput;
-	}
-
-	if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
-		do {
-			n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
-						&file->f_pos);
-			if (n >= 0) {
-				buf[n] = '\0';
-				mconsole_reply(req, buf, 0, (n > 0));
-			}
-			else {
-				mconsole_reply(req, "Read of file failed",
-					       1, 0);
-				goto out_free;
-			}
-		} while (n > 0);
-	}
-	else mconsole_reply(req, "", 0, 0);
-
- out_free:
-	kfree(buf);
- out_fput:
-	fput(file);
- out_kill:
-	deactivate_super(super);
- out: ;
-}
-#endif
-
-void mconsole_proc(struct mc_request *req)
-{
-	char path[64];
+	struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
 	char *buf;
 	int len;
-	int fd;
+	struct file *file;
 	int first_chunk = 1;
 	char *ptr = req->request.data;
 
 	ptr += strlen("proc");
 	ptr = skip_spaces(ptr);
-	snprintf(path, sizeof(path), "/proc/%s", ptr);
 
-	fd = sys_open(path, 0, 0);
-	if (fd < 0) {
+	file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY);
+	if (IS_ERR(file)) {
 		mconsole_reply(req, "Failed to open file", 1, 0);
-		printk(KERN_ERR "open %s: %d\n",path,fd);
+		printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
 		goto out;
 	}
 
 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (buf == NULL) {
 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
-		goto out_close;
+		goto out_fput;
 	}
 
-	for (;;) {
-		len = sys_read(fd, buf, PAGE_SIZE-1);
+	do {
+		loff_t pos = file->f_pos;
+		mm_segment_t old_fs = get_fs();
+		set_fs(KERNEL_DS);
+		len = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
+		set_fs(old_fs);
+		file->f_pos = pos;
 		if (len < 0) {
 			mconsole_reply(req, "Read of file failed", 1, 0);
 			goto out_free;
@@ -240,22 +162,14 @@ void mconsole_proc(struct mc_request *req)
 			mconsole_reply(req, "\n", 0, 1);
 			first_chunk = 0;
 		}
-		if (len == PAGE_SIZE-1) {
-			buf[len] = '\0';
-			mconsole_reply(req, buf, 0, 1);
-		} else {
-			buf[len] = '\0';
-			mconsole_reply(req, buf, 0, 0);
-			break;
-		}
-	}
-
+		buf[len] = '\0';
+		mconsole_reply(req, buf, 0, (len > 0));
+	} while (len > 0);
  out_free:
 	kfree(buf);
- out_close:
-	sys_close(fd);
- out:
-	/* nothing */;
+ out_fput:
+	fput(file);
+ out: ;
 }
 
 #define UML_MCONSOLE_HELPTEXT \
@@ -703,7 +617,7 @@ static void with_console(struct mc_request *req, void (*proc)(void *),
 static void sysrq_proc(void *arg)
 {
 	char *op = arg;
-	handle_sysrq(*op, NULL);
+	handle_sysrq(*op);
 }
 
 void mconsole_sysrq(struct mc_request *req)
@@ -731,10 +645,9 @@ void mconsole_sysrq(struct mc_request *req)
 
 static void stack_proc(void *arg)
 {
-	struct task_struct *from = current, *to = arg;
+	struct task_struct *task = arg;
 
-	to->thread.saved_task = from;
-	switch_to(from, to, from);
+	show_stack(task, NULL);
 }
 
 /*
@@ -803,8 +716,7 @@ static int __init mconsole_init(void)
 	register_reboot_notifier(&reboot_notifier);
 
 	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
-			     IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
-			     "mconsole", (void *)sock);
+			     IRQF_SHARED, "mconsole", (void *)sock);
 	if (err) {
 		printk(KERN_ERR "Failed to get IRQ for management console\n");
 		goto out;
@@ -856,6 +768,7 @@ static ssize_t mconsole_proc_write(struct file *file,
 static const struct file_operations mconsole_proc_fops = {
 	.owner		= THIS_MODULE,
 	.write		= mconsole_proc_write,
+	.llseek		= noop_llseek,
 };
 
 static int create_proc_mconsole(void)
@@ -867,8 +780,7 @@ static int create_proc_mconsole(void)
 
 	ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
 	if (ent == NULL) {
-		printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
-		       "failed\n");
+		printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
 		return 0;
 	}
 	return 0;