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ino.cc
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// -*- c-basic-offset: 4; related-file-name: "../include/click/ino.hh" -*-
/*
* ino.{cc,hh} -- inode numbers for Click file systems
* Eddie Kohler
*
* Copyright (c) 2002 International Computer Science Institute
* Copyright (c) 2008 Meraki, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software")
* to deal in the Software without restriction, subject to the conditions
* listed in the Click LICENSE file. These conditions include: you must
* preserve this copyright notice, and you cannot mention the copyright
* holders in advertising related to the Software without their permission.
* The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
* notice is a summary of the Click LICENSE file; the license in that file is
* legally binding.
*/
#include <click/config.h>
#include <click/glue.hh>
#include <click/ino.hh>
#include <click/router.hh>
#if INO_DEBUG
# include <click/straccum.hh>
#endif
#if CLICK_LINUXMODULE
# include <click/cxxprotect.h>
CLICK_CXX_PROTECT
# include <linux/fs.h>
CLICK_CXX_UNPROTECT
# include <click/cxxunprotect.h>
#endif
CLICK_DECLS
void
ClickIno::initialize()
{
_x = 0;
_nentries = _cap = 0;
_router = 0;
_generation = 0;
}
void
ClickIno::cleanup()
{
for (int i = 0; i < _cap; i++)
_x[i].name.~String();
CLICK_LFREE(_x, sizeof(Entry) * _cap);
initialize();
}
int
ClickIno::grow(int min_size)
{
if (_cap >= min_size)
return 0;
int new_cap = (_cap ? _cap : 128);
while (new_cap < min_size)
new_cap *= 2;
// cheat on memory: bad me!
Entry *nse = (Entry *)CLICK_LALLOC(sizeof(Entry) * new_cap);
if (!nse)
return -ENOMEM;
memcpy(nse, _x, sizeof(Entry) * _cap);
for (int i = _cap; i < new_cap; i++)
new((void *)&nse[i]) String();
CLICK_LFREE(_x, sizeof(Entry) * _cap);
_x = nse;
_cap = new_cap;
return 0;
}
static int
entry_compar(const void *v1, const void *v2, void *)
{
const ClickIno::Entry *a = reinterpret_cast<const ClickIno::Entry *>(v1);
const ClickIno::Entry *b = reinterpret_cast<const ClickIno::Entry *>(v2);
return String::compare(a->name, b->name);
}
int
ClickIno::true_prepare(Router *r, uint32_t generation)
{
// config lock must be held!
int nelem = (r ? r->nelements() : 0) + 1;
// Save some memory when replacing a large config with a small one
if (nelem < _nentries / 2 && _nentries > 256)
cleanup();
if (grow(nelem) < 0)
return -ENOMEM;
// add sentinel entry
_x[0].name = String();
_x[0].elementno_plus1 = 0;
_x[0].xindex = 0;
_x[0].skip = 0;
_x[0].flags = 0;
_nentries = 1;
// exit early if router is empty
if (nelem == 1) {
_generation = generation;
_router = r;
_x[0].flags = 0;
return 0;
}
// add entries for actual elements
for (int i = 1; i < nelem; i++) {
_x[i].name = r->ename(i - 1);
_x[i].elementno_plus1 = i;
_x[i].skip = 0;
_x[i].flags = 0;
}
// sort _x
click_qsort(&_x[1], nelem - 1, sizeof(Entry), entry_compar);
// add new _x entries for intermediate directories
int n = nelem;
for (int i = 1; i < nelem; i++) {
// make local copies of the names since we might resize _x
String name = _x[i].name;
String last_name = _x[i-1].name;
int slash = name.find_right('/');
// rely on '/' being less than any other valid name character in
// ASCII. If the prefix of "last_name" matches the part of "name"
// before a slash, then we know that "last_name" matches the whole
// component (rather than a fake match like "a/b/cc" <-> "a/b/c/e").
while (slash >= 0 && (last_name.length() < slash || memcmp(name.data(), last_name.data(), slash) != 0)) {
if (n >= _cap && grow(n + 1) < 0)
return -ENOMEM;
_x[n].name = name.substring(0, slash);
_x[n].elementno_plus1 = n;
_x[n].skip = 0;
_x[n].flags = X_FAKE;
slash = _x[n].name.find_right('/');
n++;
}
}
// resort _x if necessary
if (n != nelem)
click_qsort(&_x[1], n - 1, sizeof(Entry), entry_compar);
// calculate 'skip'
_x[0].skip = n - 1;
for (int i = 1; i < n - 1; i++) {
const String &name = _x[i].name;
int length = name.length();
int j = i + 1;
while (j < n && _x[j].name.length() > length
&& _x[j].name[length] == '/') {
assert(_x[j].name.substring(0, length) == name);
_x[i].skip++;
j++;
}
}
// calculate 'xindex'
for (int i = 1; i < n; i++)
_x[_x[i].elementno_plus1].xindex = i;
// done
_nentries = n;
_generation = generation;
_router = r;
return 0;
}
int
ClickIno::name_search(const String &n, int first_xi, int last_xi, int name_offset) const
{
while (first_xi <= last_xi) {
int mid = first_xi + ((last_xi - first_xi) >> 1);
int cmp = String::compare(n, _x[mid].name.substring(name_offset));
if (cmp == 0)
return mid;
else if (cmp < 0)
last_xi = mid - 1;
else
first_xi = mid + 1;
}
return -1;
}
int
ClickIno::element_name_search(const String &n, int elementno) const
{
int xi = xindex(elementno);
int firstpos = _x[xi].name ? _x[xi].name.length() + 1 : 0;
return name_search(n, xi + 1, next_xindex(elementno) - 1, firstpos);
}
int
ClickIno::nlink(ino_t ino)
{
// must be called with config_lock held
int elementno = INO_ELEMENTNO(ino);
// it might be a handler
if (INO_ISHANDLER(ino)) {
// Number of links per handler: one for the .h directory; plus
// if element, one for the .e/EINDEX directory; plus
// if no conflict, one for the global or element directory.
int handlerno = INO_HANDLERNO(ino);
const Handler *h = Router::handler(_router, handlerno);
return 1 + (elementno >= 0 ? 1 : 0)
+ (element_name_search(h->name(), elementno) < 0 ? 1 : 0);
}
// otherwise, it is a directory
int nlink = 2;
if (ino == INO_ENUMBERSDIR && _router)
nlink += _router->nelements();
if (INO_DT_HAS_N(ino)) {
int xi = xindex(elementno) + 1;
int next_xi = next_xindex(elementno);
if (INO_DT_HAS_H(ino) && !(_x[xi - 1].flags & X_FAKE))
nlink++; // for ".h" subdirectory
while (xi < next_xi) {
nlink++;
xi += _x[xi].skip + 1;
}
}
if (ino == INO_GLOBALDIR)
nlink++; // for ".e" subdirectory
return nlink;
}
ino_t
ClickIno::lookup(ino_t ino, const String &component)
{
// BEWARE: "component" might be a fake String pointing to mutable data; do
// not save any references to it!
// must be called with config_lock held
int elementno = INO_ELEMENTNO(ino);
int nelements = (_router ? _router->nelements() : 0);
// quit early on empty string
if (!component.length())
return 0;
// quick check for dot
if (component[0] == '.' && component.length() == 1)
return ino;
// look for numbers
if (ino == INO_ENUMBERSDIR && component[0] >= '0' && component[0] <= '9') {
int eindex = component[0] - '0';
for (int i = 1; i < component.length(); i++)
if (component[i] >= '0' && component[i] <= '9' && eindex < 1000000000)
eindex = (eindex * 10) + component[i] - '0';
else
goto number_failed;
if (!_router || eindex >= _router->nelements())
goto number_failed;
return INO_MKHUDIR(eindex);
}
number_failed:
// look for element number directory
if (ino == INO_GLOBALDIR && component.equals(".e", 2))
return INO_ENUMBERSDIR;
// look for handler directory
if (INO_DT_HAS_H(ino) && INO_DT_HAS_N(ino) && component.equals(".h", 2)
&& !(_x[xindex(elementno)].flags & X_FAKE))
return INO_MKHHDIR(elementno);
// look for names
if (INO_DT_HAS_N(ino)) {
// delimit boundaries of search region
int found = element_name_search(component, elementno);
if (found >= 0)
return INO_MKHNDIR(ClickIno::elementno(found));
}
// look for handlers (no initial period)
if (INO_DT_HAS_H(ino) && elementno < nelements && component[0] != '.') {
Element *element = Router::element(_router, elementno);
int hi = Router::hindex(element, component);
if (hi >= 0)
if (Router::handler(_router, hi)->visible())
return INO_MKHANDLER(elementno, hi);
}
// check for dot dot
if (component.equals("..", 2)) {
if (ino == INO_ENUMBERSDIR || ino == INO_MKHHDIR(-1))
return INO_GLOBALDIR;
else if (INO_DIRTYPE(ino) == INO_DT_HU)
return INO_ENUMBERSDIR;
else if (INO_DIRTYPE(ino) == INO_DT_HH)
return INO_MKHNDIR(elementno);
else {
int xi = xindex(elementno);
int slash = _x[xi].name.find_right('/');
if (slash < 0)
return INO_GLOBALDIR;
int found = name_search(_x[xi].name.substring(0, slash), 1, _nentries - 1, 0);
assert(found >= 0);
return INO_MKHNDIR(ClickIno::elementno(found));
}
}
// no luck
return 0;
}
static bool
check_handler_name(const String &hname)
{
const char *s = hname.begin(), *end = hname.end();
if (s == end || *s == '.')
return false;
for (; s != end; ++s)
if (*s == '/' || *s == 0)
return false;
return true;
}
int
ClickIno::readdir(ino_t ino, uint32_t &f_pos, filldir_t filldir, void *thunk)
{
// File positions:
// 0x000000 ..
// 0x000001 .
// 0x000002-0x0FFFFF ignored
// 0x100000-0x1FFFFF handlers
// 0x200000-0x2FFFFF numbers
// 0x300000-0x3FFFFF names
#define RD_HOFF 0x100000
#define RD_UOFF 0x200000
#define RD_NOFF 0x300000
#define RD_XOFF 0x400000
#define FILLDIR(a, b, c, d, e, f) do { if (!filldir(a, b, c, d, e, f)) return stored; else stored++; } while (0)
int elementno = INO_ELEMENTNO(ino);
int nelements = (_router ? _router->nelements() : 0);
int stored = 0;
// ".." and "."
if (f_pos == 0) {
if (ino_t dotdot = lookup(ino, String::make_stable("..", 2)))
FILLDIR("..", 2, dotdot, DT_DIR, f_pos, thunk);
f_pos++;
}
if (f_pos == 1) {
FILLDIR(".", 1, ino, DT_DIR, f_pos, thunk);
f_pos++;
}
// handler names
if (f_pos < RD_HOFF)
f_pos = RD_HOFF;
if (f_pos < RD_UOFF && INO_DT_HAS_H(ino) && elementno < nelements) {
Element *element = Router::element(_router, elementno);
Vector<int> his;
Router::element_hindexes(element, his);
while (f_pos >= RD_HOFF && f_pos < (uint32_t) his.size() + RD_HOFF) {
// Traverse element_hindexes in reverse because new handler
// names are added at the end.
int hi = his[his.size() - (f_pos - RD_HOFF) - 1];
const Handler* h = Router::handler(_router, hi);
if (!INO_DT_HAS_N(ino) || element_name_search(h->name(), elementno) < 0) {
if (h->visible() && check_handler_name(h->name()))
FILLDIR(h->name().data(), h->name().length(), INO_MKHANDLER(elementno, hi), DT_REG, f_pos, thunk);
}
f_pos++;
}
}
// subdirectory numbers
if (f_pos < RD_UOFF)
f_pos = RD_UOFF;
if (f_pos < RD_NOFF && ino == INO_ENUMBERSDIR && _router) {
char buf[10];
int nelem = _router->nelements();
while (f_pos >= RD_UOFF && f_pos < (uint32_t) RD_UOFF + nelem) {
int elem = f_pos - RD_UOFF;
sprintf(buf, "%d", elem);
FILLDIR(buf, strlen(buf), INO_MKHUDIR(elem), DT_DIR, f_pos, thunk);
f_pos++;
}
}
// figure out edges of directory
int xi = xindex(elementno) + 1;
int next_xi = next_xindex(elementno);
// subdirectory names
if (f_pos < RD_NOFF)
f_pos = RD_NOFF;
if (f_pos < RD_XOFF && INO_DT_HAS_N(ino)) {
int name_offset = _x[xi - 1].name.length();
if (name_offset > 0)
name_offset++; // skip slash
for (uint32_t j = RD_NOFF; xi < next_xi; xi += _x[xi].skip + 1, j++)
if (f_pos == j) {
FILLDIR(_x[xi].name.data() + name_offset, _x[xi].name.length() - name_offset, INO_MKHNDIR(ClickIno::elementno(xi)), DT_DIR, f_pos, thunk);
f_pos++;
}
}
// ".e" in global directory
if (f_pos < RD_XOFF)
f_pos = RD_XOFF;
if (f_pos == RD_XOFF && ino == INO_GLOBALDIR) {
FILLDIR(".e", 2, INO_ENUMBERSDIR, DT_DIR, f_pos, thunk);
f_pos++;
}
if (f_pos <= RD_XOFF + 1 && INO_DT_HAS_N(ino)
&& !(_x[xindex(elementno)].flags & X_FAKE)) {
FILLDIR(".h", 2, INO_MKHHDIR(elementno), DT_DIR, f_pos, thunk);
f_pos++;
}
f_pos = RD_XOFF + 2;
return stored;
}
#if INO_DEBUG
String
ClickIno::info() const
{
StringAccum sa;
for (int i = 0; i < _nentries; i++) {
sa << i << ". " << _x[i].name;
if (_x[i].name.length() >= 40)
sa << ' ';
else
sa.append(" ", 40 - _x[i].name.length());
sa << 'E' << (_x[i].elementno_plus1 - 1) << '/'
<< 'X' << _x[i].xindex << '\t'
<< "->" << (i + 1 + _x[i].skip);
if (_x[i].flags) {
sa << '\t';
if (_x[i].flags & X_FAKE)
sa << 'F';
}
sa << '\n';
}
return sa.take_string();
}
#endif
CLICK_ENDDECLS