aboutsummaryrefslogtreecommitdiff
path: root/fs/proc/generic.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/proc/generic.c')
-rw-r--r--fs/proc/generic.c705
1 files changed, 705 insertions, 0 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
new file mode 100644
index 00000000000..6c6315d0402
--- /dev/null
+++ b/fs/proc/generic.c
@@ -0,0 +1,705 @@
+/*
+ * proc/fs/generic.c --- generic routines for the proc-fs
+ *
+ * This file contains generic proc-fs routines for handling
+ * directories and files.
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds.
+ * Copyright (C) 1997 Theodore Ts'o
+ */
+
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/namei.h>
+#include <linux/bitops.h>
+#include <asm/uaccess.h>
+
+static ssize_t proc_file_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos);
+static ssize_t proc_file_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos);
+static loff_t proc_file_lseek(struct file *, loff_t, int);
+
+int proc_match(int len, const char *name, struct proc_dir_entry *de)
+{
+ if (de->namelen != len)
+ return 0;
+ return !memcmp(name, de->name, len);
+}
+
+static struct file_operations proc_file_operations = {
+ .llseek = proc_file_lseek,
+ .read = proc_file_read,
+ .write = proc_file_write,
+};
+
+/* buffer size is one page but our output routines use some slack for overruns */
+#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
+
+static ssize_t
+proc_file_read(struct file *file, char __user *buf, size_t nbytes,
+ loff_t *ppos)
+{
+ struct inode * inode = file->f_dentry->d_inode;
+ char *page;
+ ssize_t retval=0;
+ int eof=0;
+ ssize_t n, count;
+ char *start;
+ struct proc_dir_entry * dp;
+
+ dp = PDE(inode);
+ if (!(page = (char*) __get_free_page(GFP_KERNEL)))
+ return -ENOMEM;
+
+ while ((nbytes > 0) && !eof) {
+ count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
+
+ start = NULL;
+ if (dp->get_info) {
+ /* Handle old net routines */
+ n = dp->get_info(page, &start, *ppos, count);
+ if (n < count)
+ eof = 1;
+ } else if (dp->read_proc) {
+ /*
+ * How to be a proc read function
+ * ------------------------------
+ * Prototype:
+ * int f(char *buffer, char **start, off_t offset,
+ * int count, int *peof, void *dat)
+ *
+ * Assume that the buffer is "count" bytes in size.
+ *
+ * If you know you have supplied all the data you
+ * have, set *peof.
+ *
+ * You have three ways to return data:
+ * 0) Leave *start = NULL. (This is the default.)
+ * Put the data of the requested offset at that
+ * offset within the buffer. Return the number (n)
+ * of bytes there are from the beginning of the
+ * buffer up to the last byte of data. If the
+ * number of supplied bytes (= n - offset) is
+ * greater than zero and you didn't signal eof
+ * and the reader is prepared to take more data
+ * you will be called again with the requested
+ * offset advanced by the number of bytes
+ * absorbed. This interface is useful for files
+ * no larger than the buffer.
+ * 1) Set *start = an unsigned long value less than
+ * the buffer address but greater than zero.
+ * Put the data of the requested offset at the
+ * beginning of the buffer. Return the number of
+ * bytes of data placed there. If this number is
+ * greater than zero and you didn't signal eof
+ * and the reader is prepared to take more data
+ * you will be called again with the requested
+ * offset advanced by *start. This interface is
+ * useful when you have a large file consisting
+ * of a series of blocks which you want to count
+ * and return as wholes.
+ * (Hack by Paul.Russell@rustcorp.com.au)
+ * 2) Set *start = an address within the buffer.
+ * Put the data of the requested offset at *start.
+ * Return the number of bytes of data placed there.
+ * If this number is greater than zero and you
+ * didn't signal eof and the reader is prepared to
+ * take more data you will be called again with the
+ * requested offset advanced by the number of bytes
+ * absorbed.
+ */
+ n = dp->read_proc(page, &start, *ppos,
+ count, &eof, dp->data);
+ } else
+ break;
+
+ if (n == 0) /* end of file */
+ break;
+ if (n < 0) { /* error */
+ if (retval == 0)
+ retval = n;
+ break;
+ }
+
+ if (start == NULL) {
+ if (n > PAGE_SIZE) {
+ printk(KERN_ERR
+ "proc_file_read: Apparent buffer overflow!\n");
+ n = PAGE_SIZE;
+ }
+ n -= *ppos;
+ if (n <= 0)
+ break;
+ if (n > count)
+ n = count;
+ start = page + *ppos;
+ } else if (start < page) {
+ if (n > PAGE_SIZE) {
+ printk(KERN_ERR
+ "proc_file_read: Apparent buffer overflow!\n");
+ n = PAGE_SIZE;
+ }
+ if (n > count) {
+ /*
+ * Don't reduce n because doing so might
+ * cut off part of a data block.
+ */
+ printk(KERN_WARNING
+ "proc_file_read: Read count exceeded\n");
+ }
+ } else /* start >= page */ {
+ unsigned long startoff = (unsigned long)(start - page);
+ if (n > (PAGE_SIZE - startoff)) {
+ printk(KERN_ERR
+ "proc_file_read: Apparent buffer overflow!\n");
+ n = PAGE_SIZE - startoff;
+ }
+ if (n > count)
+ n = count;
+ }
+
+ n -= copy_to_user(buf, start < page ? page : start, n);
+ if (n == 0) {
+ if (retval == 0)
+ retval = -EFAULT;
+ break;
+ }
+
+ *ppos += start < page ? (unsigned long)start : n;
+ nbytes -= n;
+ buf += n;
+ retval += n;
+ }
+ free_page((unsigned long) page);
+ return retval;
+}
+
+static ssize_t
+proc_file_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct proc_dir_entry * dp;
+
+ dp = PDE(inode);
+
+ if (!dp->write_proc)
+ return -EIO;
+
+ /* FIXME: does this routine need ppos? probably... */
+ return dp->write_proc(file, buffer, count, dp->data);
+}
+
+
+static loff_t
+proc_file_lseek(struct file *file, loff_t offset, int orig)
+{
+ lock_kernel();
+
+ switch (orig) {
+ case 0:
+ if (offset < 0)
+ goto out;
+ file->f_pos = offset;
+ unlock_kernel();
+ return(file->f_pos);
+ case 1:
+ if (offset + file->f_pos < 0)
+ goto out;
+ file->f_pos += offset;
+ unlock_kernel();
+ return(file->f_pos);
+ case 2:
+ goto out;
+ default:
+ goto out;
+ }
+
+out:
+ unlock_kernel();
+ return -EINVAL;
+}
+
+static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = dentry->d_inode;
+ struct proc_dir_entry *de = PDE(inode);
+ int error;
+
+ error = inode_change_ok(inode, iattr);
+ if (error)
+ goto out;
+
+ error = inode_setattr(inode, iattr);
+ if (error)
+ goto out;
+
+ de->uid = inode->i_uid;
+ de->gid = inode->i_gid;
+ de->mode = inode->i_mode;
+out:
+ return error;
+}
+
+static struct inode_operations proc_file_inode_operations = {
+ .setattr = proc_notify_change,
+};
+
+/*
+ * This function parses a name such as "tty/driver/serial", and
+ * returns the struct proc_dir_entry for "/proc/tty/driver", and
+ * returns "serial" in residual.
+ */
+static int xlate_proc_name(const char *name,
+ struct proc_dir_entry **ret, const char **residual)
+{
+ const char *cp = name, *next;
+ struct proc_dir_entry *de;
+ int len;
+
+ de = &proc_root;
+ while (1) {
+ next = strchr(cp, '/');
+ if (!next)
+ break;
+
+ len = next - cp;
+ for (de = de->subdir; de ; de = de->next) {
+ if (proc_match(len, cp, de))
+ break;
+ }
+ if (!de)
+ return -ENOENT;
+ cp += len + 1;
+ }
+ *residual = cp;
+ *ret = de;
+ return 0;
+}
+
+static DEFINE_IDR(proc_inum_idr);
+static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
+
+#define PROC_DYNAMIC_FIRST 0xF0000000UL
+
+/*
+ * Return an inode number between PROC_DYNAMIC_FIRST and
+ * 0xffffffff, or zero on failure.
+ */
+static unsigned int get_inode_number(void)
+{
+ int i, inum = 0;
+ int error;
+
+retry:
+ if (idr_pre_get(&proc_inum_idr, GFP_KERNEL) == 0)
+ return 0;
+
+ spin_lock(&proc_inum_lock);
+ error = idr_get_new(&proc_inum_idr, NULL, &i);
+ spin_unlock(&proc_inum_lock);
+ if (error == -EAGAIN)
+ goto retry;
+ else if (error)
+ return 0;
+
+ inum = (i & MAX_ID_MASK) + PROC_DYNAMIC_FIRST;
+
+ /* inum will never be more than 0xf0ffffff, so no check
+ * for overflow.
+ */
+
+ return inum;
+}
+
+static void release_inode_number(unsigned int inum)
+{
+ int id = (inum - PROC_DYNAMIC_FIRST) | ~MAX_ID_MASK;
+
+ spin_lock(&proc_inum_lock);
+ idr_remove(&proc_inum_idr, id);
+ spin_unlock(&proc_inum_lock);
+}
+
+static int proc_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ nd_set_link(nd, PDE(dentry->d_inode)->data);
+ return 0;
+}
+
+static struct inode_operations proc_link_inode_operations = {
+ .readlink = generic_readlink,
+ .follow_link = proc_follow_link,
+};
+
+/*
+ * As some entries in /proc are volatile, we want to
+ * get rid of unused dentries. This could be made
+ * smarter: we could keep a "volatile" flag in the
+ * inode to indicate which ones to keep.
+ */
+static int proc_delete_dentry(struct dentry * dentry)
+{
+ return 1;
+}
+
+static struct dentry_operations proc_dentry_operations =
+{
+ .d_delete = proc_delete_dentry,
+};
+
+/*
+ * Don't create negative dentries here, return -ENOENT by hand
+ * instead.
+ */
+struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
+{
+ struct inode *inode = NULL;
+ struct proc_dir_entry * de;
+ int error = -ENOENT;
+
+ lock_kernel();
+ de = PDE(dir);
+ if (de) {
+ for (de = de->subdir; de ; de = de->next) {
+ if (de->namelen != dentry->d_name.len)
+ continue;
+ if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
+ unsigned int ino = de->low_ino;
+
+ error = -EINVAL;
+ inode = proc_get_inode(dir->i_sb, ino, de);
+ break;
+ }
+ }
+ }
+ unlock_kernel();
+
+ if (inode) {
+ dentry->d_op = &proc_dentry_operations;
+ d_add(dentry, inode);
+ return NULL;
+ }
+ return ERR_PTR(error);
+}
+
+/*
+ * This returns non-zero if at EOF, so that the /proc
+ * root directory can use this and check if it should
+ * continue with the <pid> entries..
+ *
+ * Note that the VFS-layer doesn't care about the return
+ * value of the readdir() call, as long as it's non-negative
+ * for success..
+ */
+int proc_readdir(struct file * filp,
+ void * dirent, filldir_t filldir)
+{
+ struct proc_dir_entry * de;
+ unsigned int ino;
+ int i;
+ struct inode *inode = filp->f_dentry->d_inode;
+ int ret = 0;
+
+ lock_kernel();
+
+ ino = inode->i_ino;
+ de = PDE(inode);
+ if (!de) {
+ ret = -EINVAL;
+ goto out;
+ }
+ i = filp->f_pos;
+ switch (i) {
+ case 0:
+ if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
+ goto out;
+ i++;
+ filp->f_pos++;
+ /* fall through */
+ case 1:
+ if (filldir(dirent, "..", 2, i,
+ parent_ino(filp->f_dentry),
+ DT_DIR) < 0)
+ goto out;
+ i++;
+ filp->f_pos++;
+ /* fall through */
+ default:
+ de = de->subdir;
+ i -= 2;
+ for (;;) {
+ if (!de) {
+ ret = 1;
+ goto out;
+ }
+ if (!i)
+ break;
+ de = de->next;
+ i--;
+ }
+
+ do {
+ if (filldir(dirent, de->name, de->namelen, filp->f_pos,
+ de->low_ino, de->mode >> 12) < 0)
+ goto out;
+ filp->f_pos++;
+ de = de->next;
+ } while (de);
+ }
+ ret = 1;
+out: unlock_kernel();
+ return ret;
+}
+
+/*
+ * These are the generic /proc directory operations. They
+ * use the in-memory "struct proc_dir_entry" tree to parse
+ * the /proc directory.
+ */
+static struct file_operations proc_dir_operations = {
+ .read = generic_read_dir,
+ .readdir = proc_readdir,
+};
+
+/*
+ * proc directories can do almost nothing..
+ */
+static struct inode_operations proc_dir_inode_operations = {
+ .lookup = proc_lookup,
+ .setattr = proc_notify_change,
+};
+
+static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
+{
+ unsigned int i;
+
+ i = get_inode_number();
+ if (i == 0)
+ return -EAGAIN;
+ dp->low_ino = i;
+ dp->next = dir->subdir;
+ dp->parent = dir;
+ dir->subdir = dp;
+ if (S_ISDIR(dp->mode)) {
+ if (dp->proc_iops == NULL) {
+ dp->proc_fops = &proc_dir_operations;
+ dp->proc_iops = &proc_dir_inode_operations;
+ }
+ dir->nlink++;
+ } else if (S_ISLNK(dp->mode)) {
+ if (dp->proc_iops == NULL)
+ dp->proc_iops = &proc_link_inode_operations;
+ } else if (S_ISREG(dp->mode)) {
+ if (dp->proc_fops == NULL)
+ dp->proc_fops = &proc_file_operations;
+ if (dp->proc_iops == NULL)
+ dp->proc_iops = &proc_file_inode_operations;
+ }
+ return 0;
+}
+
+/*
+ * Kill an inode that got unregistered..
+ */
+static void proc_kill_inodes(struct proc_dir_entry *de)
+{
+ struct list_head *p;
+ struct super_block *sb = proc_mnt->mnt_sb;
+
+ /*
+ * Actually it's a partial revoke().
+ */
+ file_list_lock();
+ list_for_each(p, &sb->s_files) {
+ struct file * filp = list_entry(p, struct file, f_list);
+ struct dentry * dentry = filp->f_dentry;
+ struct inode * inode;
+ struct file_operations *fops;
+
+ if (dentry->d_op != &proc_dentry_operations)
+ continue;
+ inode = dentry->d_inode;
+ if (PDE(inode) != de)
+ continue;
+ fops = filp->f_op;
+ filp->f_op = NULL;
+ fops_put(fops);
+ }
+ file_list_unlock();
+}
+
+static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
+ const char *name,
+ mode_t mode,
+ nlink_t nlink)
+{
+ struct proc_dir_entry *ent = NULL;
+ const char *fn = name;
+ int len;
+
+ /* make sure name is valid */
+ if (!name || !strlen(name)) goto out;
+
+ if (!(*parent) && xlate_proc_name(name, parent, &fn) != 0)
+ goto out;
+
+ /* At this point there must not be any '/' characters beyond *fn */
+ if (strchr(fn, '/'))
+ goto out;
+
+ len = strlen(fn);
+
+ ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
+ if (!ent) goto out;
+
+ memset(ent, 0, sizeof(struct proc_dir_entry));
+ memcpy(((char *) ent) + sizeof(struct proc_dir_entry), fn, len + 1);
+ ent->name = ((char *) ent) + sizeof(*ent);
+ ent->namelen = len;
+ ent->mode = mode;
+ ent->nlink = nlink;
+ out:
+ return ent;
+}
+
+struct proc_dir_entry *proc_symlink(const char *name,
+ struct proc_dir_entry *parent, const char *dest)
+{
+ struct proc_dir_entry *ent;
+
+ ent = proc_create(&parent,name,
+ (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
+
+ if (ent) {
+ ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
+ if (ent->data) {
+ strcpy((char*)ent->data,dest);
+ if (proc_register(parent, ent) < 0) {
+ kfree(ent->data);
+ kfree(ent);
+ ent = NULL;
+ }
+ } else {
+ kfree(ent);
+ ent = NULL;
+ }
+ }
+ return ent;
+}
+
+struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
+ struct proc_dir_entry *parent)
+{
+ struct proc_dir_entry *ent;
+
+ ent = proc_create(&parent, name, S_IFDIR | mode, 2);
+ if (ent) {
+ ent->proc_fops = &proc_dir_operations;
+ ent->proc_iops = &proc_dir_inode_operations;
+
+ if (proc_register(parent, ent) < 0) {
+ kfree(ent);
+ ent = NULL;
+ }
+ }
+ return ent;
+}
+
+struct proc_dir_entry *proc_mkdir(const char *name,
+ struct proc_dir_entry *parent)
+{
+ return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
+}
+
+struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
+ struct proc_dir_entry *parent)
+{
+ struct proc_dir_entry *ent;
+ nlink_t nlink;
+
+ if (S_ISDIR(mode)) {
+ if ((mode & S_IALLUGO) == 0)
+ mode |= S_IRUGO | S_IXUGO;
+ nlink = 2;
+ } else {
+ if ((mode & S_IFMT) == 0)
+ mode |= S_IFREG;
+ if ((mode & S_IALLUGO) == 0)
+ mode |= S_IRUGO;
+ nlink = 1;
+ }
+
+ ent = proc_create(&parent,name,mode,nlink);
+ if (ent) {
+ if (S_ISDIR(mode)) {
+ ent->proc_fops = &proc_dir_operations;
+ ent->proc_iops = &proc_dir_inode_operations;
+ }
+ if (proc_register(parent, ent) < 0) {
+ kfree(ent);
+ ent = NULL;
+ }
+ }
+ return ent;
+}
+
+void free_proc_entry(struct proc_dir_entry *de)
+{
+ unsigned int ino = de->low_ino;
+
+ if (ino < PROC_DYNAMIC_FIRST)
+ return;
+
+ release_inode_number(ino);
+
+ if (S_ISLNK(de->mode) && de->data)
+ kfree(de->data);
+ kfree(de);
+}
+
+/*
+ * Remove a /proc entry and free it if it's not currently in use.
+ * If it is in use, we set the 'deleted' flag.
+ */
+void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
+{
+ struct proc_dir_entry **p;
+ struct proc_dir_entry *de;
+ const char *fn = name;
+ int len;
+
+ if (!parent && xlate_proc_name(name, &parent, &fn) != 0)
+ goto out;
+ len = strlen(fn);
+ for (p = &parent->subdir; *p; p=&(*p)->next ) {
+ if (!proc_match(len, fn, *p))
+ continue;
+ de = *p;
+ *p = de->next;
+ de->next = NULL;
+ if (S_ISDIR(de->mode))
+ parent->nlink--;
+ proc_kill_inodes(de);
+ de->nlink = 0;
+ WARN_ON(de->subdir);
+ if (!atomic_read(&de->count))
+ free_proc_entry(de);
+ else {
+ de->deleted = 1;
+ printk("remove_proc_entry: %s/%s busy, count=%d\n",
+ parent->name, de->name, atomic_read(&de->count));
+ }
+ break;
+ }
+out:
+ return;
+}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-25 06:40:43 +0000