diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
commit | 57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch) | |
tree | 5e910f0e82173f4ef4f51111366a3f1299037a7b /fs/proc/self.c |
Initial import
Diffstat (limited to 'fs/proc/self.c')
-rw-r--r-- | fs/proc/self.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/fs/proc/self.c b/fs/proc/self.c new file mode 100644 index 000000000..6195b4a7c --- /dev/null +++ b/fs/proc/self.c @@ -0,0 +1,84 @@ +#include <linux/sched.h> +#include <linux/namei.h> +#include <linux/slab.h> +#include <linux/pid_namespace.h> +#include "internal.h" + +/* + * /proc/self: + */ +static int proc_self_readlink(struct dentry *dentry, char __user *buffer, + int buflen) +{ + struct pid_namespace *ns = dentry->d_sb->s_fs_info; + pid_t tgid = task_tgid_nr_ns(current, ns); + char tmp[PROC_NUMBUF]; + if (!tgid) + return -ENOENT; + sprintf(tmp, "%d", tgid); + return readlink_copy(buffer, buflen, tmp); +} + +static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + struct pid_namespace *ns = dentry->d_sb->s_fs_info; + pid_t tgid = task_tgid_nr_ns(current, ns); + char *name = ERR_PTR(-ENOENT); + if (tgid) { + /* 11 for max length of signed int in decimal + NULL term */ + name = kmalloc(12, GFP_KERNEL); + if (!name) + name = ERR_PTR(-ENOMEM); + else + sprintf(name, "%d", tgid); + } + nd_set_link(nd, name); + return NULL; +} + +static const struct inode_operations proc_self_inode_operations = { + .readlink = proc_self_readlink, + .follow_link = proc_self_follow_link, + .put_link = kfree_put_link, +}; + +static unsigned self_inum; + +int proc_setup_self(struct super_block *s) +{ + struct inode *root_inode = d_inode(s->s_root); + struct pid_namespace *ns = s->s_fs_info; + struct dentry *self; + + mutex_lock(&root_inode->i_mutex); + self = d_alloc_name(s->s_root, "self"); + if (self) { + struct inode *inode = new_inode_pseudo(s); + if (inode) { + inode->i_ino = self_inum; + inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; + inode->i_mode = S_IFLNK | S_IRWXUGO; + inode->i_uid = GLOBAL_ROOT_UID; + inode->i_gid = GLOBAL_ROOT_GID; + inode->i_op = &proc_self_inode_operations; + d_add(self, inode); + } else { + dput(self); + self = ERR_PTR(-ENOMEM); + } + } else { + self = ERR_PTR(-ENOMEM); + } + mutex_unlock(&root_inode->i_mutex); + if (IS_ERR(self)) { + pr_err("proc_fill_super: can't allocate /proc/self\n"); + return PTR_ERR(self); + } + ns->proc_self = self; + return 0; +} + +void __init proc_self_init(void) +{ + proc_alloc_inum(&self_inum); +} |