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/* -*- linux-c -*-
*
* /proc command channels
* Copyright (C) 2007-2009 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _STP_PROCFS_C_
#define _STP_PROCFS_C_
#if (!defined(STAPCONF_PATH_LOOKUP) && !defined(STAPCONF_KERN_PATH_PARENT) \
&& !defined(STAPCONF_VFS_PATH_LOOKUP) && !defined(STAPCONF_KERN_PATH))
#error "Either path_lookup(), kern_path_parent(), vfs_path_lookup(), or kern_path() must be exported by the kernel."
#endif
#ifdef STAPCONF_KERN_PATH
#include <linux/namei.h>
#endif
#ifdef STAPCONF_VFS_PATH_LOOKUP
#include <linux/mount.h>
#include <linux/pid_namespace.h>
#endif
#include "proc_fs_compatibility.h"
#include "uidgid_compatibility.h"
/* If STAPCONF_PDE_DATA* aren't defined, we're using the original /proc
* interface (where 'struct proc_dir_entry' isn't opaque). In this
* case allow the (undocumented) feature of slashes
* (i.e. subdirectories) in paths. */
#if !defined(STAPCONF_PDE_DATA) && !defined(STAPCONF_PDE_DATA2)
#define _STP_ALLOW_PROCFS_PATH_SUBDIRS
#endif
/* The maximum number of files that can be opened. Plus if
* _STP_ALLOW_PROCFS_PATH_SUBDIRS, add number of directories.
*/
#ifndef STP_MAX_PROCFS_FILES
#error "need STP_MAX_PROCFS_FILES"
#endif
static int _stp_num_pde = 0;
static struct proc_dir_entry *_stp_pde[STP_MAX_PROCFS_FILES];
static void _stp_close_procfs(void);
#ifdef _STP_ALLOW_PROCFS_PATH_SUBDIRS
/*
* This checks our local cache to see if we already made the dir.
*/
static struct proc_dir_entry *_stp_procfs_lookup(const char *dir, struct proc_dir_entry *parent)
{
int i;
for (i = 0; i <_stp_num_pde; i++) {
struct proc_dir_entry *pde = _stp_pde[i];
if (pde->parent == parent && !strcmp(dir, pde->name))
return pde;
}
return NULL;
}
#endif /* _STP_ALLOW_PROCFS_PATH_SUBDIRS */
static int _stp_create_procfs(const char *path,
#ifdef STAPCONF_PROC_OPS
const struct proc_ops *fops,
#else
const struct file_operations *fops,
#endif
int perm, void *data)
{
const char *p; char *next;
struct proc_dir_entry *last_dir, *de;
if (_stp_num_pde >= STP_MAX_PROCFS_FILES)
goto too_many;
last_dir = _stp_procfs_module_dir;
/* if no path, use default one */
if (strlen(path) == 0)
p = "command";
else
p = path;
#ifdef _STP_ALLOW_PROCFS_PATH_SUBDIRS
while ((next = strchr(p, '/'))) {
if (_stp_num_pde == STP_MAX_PROCFS_FILES)
goto too_many;
*next = 0;
de = _stp_procfs_lookup(p, last_dir);
if (de == NULL) {
last_dir = proc_mkdir(p, last_dir);
if (!last_dir) {
_stp_error("Could not create directory \"%s\"\n", p);
goto err;
}
_stp_pde[_stp_num_pde++] = last_dir;
#ifdef STAPCONF_PROCFS_OWNER
last_dir->owner = THIS_MODULE;
#endif
proc_set_user(last_dir, KUIDT_INIT(_stp_uid),
KGIDT_INIT(_stp_gid));
}
else {
last_dir = de;
}
p = next + 1;
}
#else /* !_STP_ALLOW_PROCFS_PATH_SUBDIRS */
if (strchr(p, '/') != NULL) {
_stp_error("Could not create path \"%s\","
" contains subdirectories\n", p);
goto err;
}
#endif /* !_STP_ALLOW_PROCFS_PATH_SUBDIRS */
if (_stp_num_pde == STP_MAX_PROCFS_FILES)
goto too_many;
de = proc_create_data(p, perm, last_dir, fops, data);
if (de == NULL)
return 0; // already created
#ifdef STAPCONF_PROCFS_OWNER
de->owner = THIS_MODULE;
#endif
proc_set_user(de, KUIDT_INIT(_stp_uid), KGIDT_INIT(_stp_gid));
_stp_pde[_stp_num_pde++] = de;
return 0;
too_many:
_stp_error("Attempted to open too many procfs files. Maximum is %d\n",
STP_MAX_PROCFS_FILES);
err:
_stp_close_procfs();
return -1;
}
static void _stp_close_procfs(void)
{
int i;
for (i = _stp_num_pde-1; i >= 0; i--) {
struct proc_dir_entry *pde = _stp_pde[i];
proc_remove(pde);
}
_stp_num_pde = 0;
}
#endif /* _STP_PROCFS_C_ */
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