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7ec32df7ea
string_pool (string interning) was using STL strings with lots of extra constructions, when all we need is a const char array. We can use charpool for that and get all the benefits there of tightly-packed heap allocations.
147 lines
6.3 KiB
C++
147 lines
6.3 KiB
C++
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/***************************************************************************
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* charpool.cc -- Handles Nmap's "character pool" memory allocation *
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* system. *
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* *
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***********************IMPORTANT NMAP LICENSE TERMS************************
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* *
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* The Nmap Security Scanner is (C) 1996-2022 Nmap Software LLC ("The Nmap *
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* Project"). Nmap is also a registered trademark of the Nmap Project. *
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* *
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* This program is distributed under the terms of the Nmap Public Source *
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* License (NPSL). The exact license text applying to a particular Nmap *
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* release or source code control revision is contained in the LICENSE *
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* file distributed with that version of Nmap or source code control *
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* revision. More Nmap copyright/legal information is available from *
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* https://nmap.org/book/man-legal.html, and further information on the *
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* NPSL license itself can be found at https://nmap.org/npsl/ . This *
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* header summarizes some key points from the Nmap license, but is no *
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* substitute for the actual license text. *
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* *
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* Nmap is generally free for end users to download and use themselves, *
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* including commercial use. It is available from https://nmap.org. *
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* *
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* The Nmap license generally prohibits companies from using and *
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* redistributing Nmap in commercial products, but we sell a special Nmap *
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* OEM Edition with a more permissive license and special features for *
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* this purpose. See https://nmap.org/oem/ *
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* *
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* If you have received a written Nmap license agreement or contract *
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* stating terms other than these (such as an Nmap OEM license), you may *
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* choose to use and redistribute Nmap under those terms instead. *
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* *
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* The official Nmap Windows builds include the Npcap software *
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* (https://npcap.com) for packet capture and transmission. It is under *
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* separate license terms which forbid redistribution without special *
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* permission. So the official Nmap Windows builds may not be *
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* redistributed without special permission (such as an Nmap OEM *
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* license). *
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* *
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* Source is provided to this software because we believe users have a *
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* right to know exactly what a program is going to do before they run it. *
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* This also allows you to audit the software for security holes. *
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* *
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* Source code also allows you to port Nmap to new platforms, fix bugs, *
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* and add new features. You are highly encouraged to submit your *
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* changes as a Github PR or by email to the dev@nmap.org mailing list *
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* for possible incorporation into the main distribution. Unless you *
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* specify otherwise, it is understood that you are offering us very *
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* broad rights to use your submissions as described in the Nmap Public *
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* Source License Contributor Agreement. This is important because we *
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* fund the project by selling licenses with various terms, and also *
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* because the inability to relicense code has caused devastating *
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* problems for other Free Software projects (such as KDE and NASM). *
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* *
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* The free version of Nmap is distributed in the hope that it will be *
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Warranties, *
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* indemnification and commercial support are all available through the *
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* Npcap OEM program--see https://nmap.org/oem/ *
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* *
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***************************************************************************/
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/* $Id$ */
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#include <stddef.h>
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#include "nbase.h"
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/* Character pool memory allocation */
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#include "charpool.h"
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#include "nmap_error.h"
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static char *charpool[16];
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static int currentcharpool;
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static size_t currentcharpoolsz;
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static size_t nexti;
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/* Allocated blocks are allocated to multiples of ALIGN_ON. This is the
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definition used by the malloc in Glibc 2.7, which says that it "suffices for
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nearly all current machines and C compilers." */
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#define ALIGN_ON (2 * sizeof(size_t))
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static int cp_init(void) {
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static int charpool_initialized = 0;
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if (charpool_initialized) return 0;
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/* Create our char pool */
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currentcharpool = 0;
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currentcharpoolsz = 16384;
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nexti = 0;
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charpool[0] = (char *) safe_malloc(currentcharpoolsz);
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charpool_initialized = 1;
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return 0;
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}
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void cp_free(void) {
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int ccp;
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for(ccp=0; ccp <= currentcharpool; ccp++)
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if(charpool[ccp]){
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free(charpool[ccp]);
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charpool[ccp] = NULL;
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}
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currentcharpool = 0;
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}
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static inline void cp_grow(void) {
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/* Doh! We've got to make room */
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if (++currentcharpool > 15) {
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fatal("Character Pool is out of buckets!");
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}
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currentcharpoolsz <<= 1;
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nexti = 0;
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charpool[currentcharpool] = (char *) safe_malloc(currentcharpoolsz);
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}
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void *cp_alloc(int sz) {
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char *p;
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int modulus;
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cp_init();
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if ((modulus = sz % ALIGN_ON))
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sz += ALIGN_ON - modulus;
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if (nexti + sz <= currentcharpoolsz) {
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p = charpool[currentcharpool] + nexti;
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nexti += sz;
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return p;
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}
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/* Doh! We've got to make room */
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cp_grow();
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return cp_alloc(sz);
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}
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const char *cp_strndup(const char *src, int len) {
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char *dst = (char *) cp_alloc(len + 1); // Additional byte for null terminator
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dst[len] = '\0';
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return (const char *) memcpy(dst, src, len);
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}
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const char *cp_strdup(const char *src) {
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return cp_strndup(src, strlen(src));
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}
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