From:Suzuki K.Poulose <suz...@in.ibm.com>
Keep track of the core generation requests. Concurrent core generation requests
for the same target process are not allowed.
Signed-off-by: Suzuki K. Poulose <suz...@in.ibm.com>
Signed-off-by: Ananth N.Mavinakayanahalli <ana...@in.ibm.com>
---
fs/proc/gencore.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/proc/gencore.h | 12 +++++++
2 files changed, 96 insertions(+), 2 deletions(-)
create mode 100644 fs/proc/gencore.h
diff --git a/fs/proc/gencore.c b/fs/proc/gencore.c
index 115f1e4..580a8b5 100644
--- a/fs/proc/gencore.c
+++ b/fs/proc/gencore.c
@@ -23,23 +23,105 @@
*/
#include <linux/seq_file.h>
+#include <linux/slab.h>
#include "internal.h"
+#include "gencore.h"
+
+static LIST_HEAD(core_list);
+static DEFINE_MUTEX(core_mutex);
+
+/* Called with core_mutex held */
+static struct core_proc* get_core_proc(struct task_struct *t)
+{
+ struct core_proc *cp;
+
+ list_for_each_entry(cp, &core_list, list) {
+ if (cp->task == t->group_leader)
+ return cp;
+ }
+ return NULL;
+}
static ssize_t read_gencore(struct file *file, char __user *buffer,
size_t buflen, loff_t *fpos)
{
- return 0;
+ struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
+ struct core_proc *cp;
+ ssize_t ret = 0;
+
+ if (!task)
+ return -EIO;
+
+ mutex_lock(&core_mutex);
+ cp = get_core_proc(task);
+ if (!cp) {
+ mutex_unlock(&core_mutex);
+ ret = -EIO;
+ goto out;
+ }
+ mutex_unlock(&core_mutex);
+
+out:
+ put_task_struct(task);
+ return ret;
}
static int release_gencore(struct inode *inode, struct file *file)
{
+ struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
+ struct core_proc *cp;
+
+ if (!task)
+ return -EIO;
+
+ mutex_lock(&core_mutex);
+ cp = get_core_proc(task);
+ if (cp) {
+ list_del(&cp->list);
+ kfree(cp);
+ }
+ mutex_unlock(&core_mutex);
+ put_task_struct(task);
return 0;
}
+/*
+ * Validate if the call is valid. We also need to prevent >1 open
+ * of the same file.
+ */
static int open_gencore(struct inode *inode, struct file *filp)
{
- return 0;
+ struct task_struct *task = get_proc_task(inode);
+ struct core_proc *cp;
+ int ret = 0;
+ if (!task)
+ return -ENOENT;
+
+ mutex_lock(&core_mutex);
+ cp = get_core_proc(task);
+ mutex_unlock(&core_mutex);
+ if (cp) {
+ ret = -EALREADY;
+ goto out;
+ }
+
+ cp = kzalloc(sizeof (*cp), GFP_KERNEL);
+ if (!cp) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ cp->task = task->group_leader;
+ INIT_LIST_HEAD(&cp->list);
+ mutex_lock(&core_mutex);
+ list_add(&cp->list, &core_list);
+ mutex_unlock(&core_mutex);
+
+out:
+ put_task_struct(task);
+ return ret;
}
+
const struct file_operations proc_gen_core_operations = {
.open = open_gencore,
.read = read_gencore,
diff --git a/fs/proc/gencore.h b/fs/proc/gencore.h
new file mode 100644
index 0000000..c98fddf
--- /dev/null
+++ b/fs/proc/gencore.h
@@ -0,0 +1,12 @@
+#ifndef __GEN_CORE_H
+#define __GEN_CORE_H
+
+#include <linux/list.h>
+#include <linux/sched.h>
+
+struct core_proc {
+ struct list_head list;
+ struct task_struct *task;
+};
+
+#endif
--
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