1 files changed, 70 insertions, 3 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index af643b5aefe..e42bbd843ed 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1265,6 +1265,72 @@ static const struct file_operations proc_pid_sched_operations = {
 
 #endif
 
+static ssize_t comm_write(struct file *file, const char __user *buf,
+                                size_t count, loff_t *offset)
+{
+        struct inode *inode = file->f_path.dentry->d_inode;
+        struct task_struct *p;
+        char buffer[TASK_COMM_LEN];
+
+        memset(buffer, 0, sizeof(buffer));
+        if (count > sizeof(buffer) - 1)
+                count = sizeof(buffer) - 1;
+        if (copy_from_user(buffer, buf, count))
+                return -EFAULT;
+
+        p = get_proc_task(inode);
+        if (!p)
+                return -ESRCH;
+
+        if (same_thread_group(current, p))
+                set_task_comm(p, buffer);
+        else
+                count = -EINVAL;
+
+        put_task_struct(p);
+
+        return count;
+}
+
+static int comm_show(struct seq_file *m, void *v)
+{
+        struct inode *inode = m->private;
+        struct task_struct *p;
+
+        p = get_proc_task(inode);
+        if (!p)
+                return -ESRCH;
+
+        task_lock(p);
+        seq_printf(m, "%s\n", p->comm);
+        task_unlock(p);
+
+        put_task_struct(p);
+
+        return 0;
+}
+
+static int comm_open(struct inode *inode, struct file *filp)
+{
+        int ret;
+
+        ret = single_open(filp, comm_show, NULL);
+        if (!ret) {
+                struct seq_file *m = filp->private_data;
+
+                m->private = inode;
+        }
+        return ret;
+}
+
+static const struct file_operations proc_pid_set_comm_operations = {
+        .open           = comm_open,
+        .read           = seq_read,
+        .write          = comm_write,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
 /*
  * We added or removed a vma mapping the executable. The vmas are only mapped
  * during exec and are not mapped with the mmap system call.
@@ -1353,7 +1419,6 @@ static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
                 goto out;
 
         error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
-        nd->last_type = LAST_BIND;
 out:
         return ERR_PTR(error);
 }
@@ -2200,7 +2265,7 @@ static const struct inode_operations proc_attr_dir_inode_operations = {
 
 #endif
 
-#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
+#ifdef CONFIG_ELF_CORE
 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
                                          size_t count, loff_t *ppos)
 {
@@ -2504,6 +2569,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_SCHED_DEBUG
         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
 #endif
+        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
         INF("syscall",    S_IRUSR, proc_pid_syscall),
 #endif
@@ -2556,7 +2622,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_FAULT_INJECTION
         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
 #endif
-#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
+#ifdef CONFIG_ELF_CORE
         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
 #endif
 #ifdef CONFIG_TASK_IO_ACCOUNTING
@@ -2838,6 +2904,7 @@ static const struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_SCHED_DEBUG
         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
 #endif
+        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
         INF("syscall",   S_IRUSR, proc_pid_syscall),
 #endif