xref: /third_party/mksh/lalloc.c (revision c84f3f3c) 
1/*-
2 * Copyright (c) 2009, 2010, 2011, 2013, 2014, 2016
3 *	mirabilos <m@mirbsd.org>
4 *
5 * Provided that these terms and disclaimer and all copyright notices
6 * are retained or reproduced in an accompanying document, permission
7 * is granted to deal in this work without restriction, including un-
8 * limited rights to use, publicly perform, distribute, sell, modify,
9 * merge, give away, or sublicence.
10 *
11 * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
12 * the utmost extent permitted by applicable law, neither express nor
13 * implied; without malicious intent or gross negligence. In no event
14 * may a licensor, author or contributor be held liable for indirect,
15 * direct, other damage, loss, or other issues arising in any way out
16 * of dealing in the work, even if advised of the possibility of such
17 * damage or existence of a defect, except proven that it results out
18 * of said person's immediate fault when using the work as intended.
19 */
20
21#include "sh.h"
22#ifdef MKSH_ALLOC_CATCH_UNDERRUNS
23#include <err.h>
24#endif
25
26__RCSID("$MirOS: src/bin/mksh/lalloc.c,v 1.26 2016/02/26 21:53:36 tg Exp $");
27
28/* build with CPPFLAGS+= -DUSE_REALLOC_MALLOC=0 on ancient systems */
29#if defined(USE_REALLOC_MALLOC) && (USE_REALLOC_MALLOC == 0)
30#define remalloc(p,n)	((p) == NULL ? malloc_osi(n) : realloc_osi((p), (n)))
31#else
32#define remalloc(p,n)	realloc_osi((p), (n))
33#endif
34
35
36static struct lalloc_common *findptr(struct lalloc_common **, char *, Area *);
37
38#ifndef MKSH_ALLOC_CATCH_UNDERRUNS
39#define ALLOC_ISUNALIGNED(p) (((size_t)(p)) % sizeof(struct lalloc_common))
40#else
41#define ALLOC_ISUNALIGNED(p) (((size_t)(p)) & 4095)
42#undef remalloc
43#undef free_osimalloc
44
45static void
46free_osimalloc(void *ptr)
47{
48	struct lalloc_item *lp = ptr;
49
50	if (munmap(lp, lp->len))
51		err(1, "free_osimalloc");
52}
53
54static void *
55remalloc(void *ptr, size_t size)
56{
57	struct lalloc_item *lp, *lold = ptr;
58
59	size = (size + 4095) & ~(size_t)4095;
60
61	if (lold && lold->len >= size)
62		return (ptr);
63
64	if ((lp = mmap(NULL, size, PROT_READ | PROT_WRITE,
65	    MAP_ANON | MAP_PRIVATE, -1, (off_t)0)) == MAP_FAILED)
66		err(1, "remalloc: mmap(%zu)", size);
67	if (ALLOC_ISUNALIGNED(lp))
68		errx(1, "remalloc: unaligned(%p)", lp);
69	if (mprotect(((char *)lp) + 4096, 4096, PROT_NONE))
70		err(1, "remalloc: mprotect");
71	lp->len = size;
72
73	if (lold) {
74		memcpy(((char *)lp) + 8192, ((char *)lold) + 8192,
75		    lold->len - 8192);
76		if (munmap(lold, lold->len))
77			err(1, "remalloc: munmap");
78	}
79
80	return (lp);
81}
82#endif
83
84void
85ainit(Area *ap)
86{
87#ifdef MKSH_ALLOC_CATCH_UNDERRUNS
88	if (sysconf(_SC_PAGESIZE) != 4096) {
89		fprintf(stderr, "mksh: fatal: pagesize %lu not 4096!\n",
90		    sysconf(_SC_PAGESIZE));
91		fflush(stderr);
92		abort();
93	}
94#endif
95	/* area pointer and items share struct lalloc_common */
96	ap->next = NULL;
97}
98
99static struct lalloc_common *
100findptr(struct lalloc_common **lpp, char *ptr, Area *ap)
101{
102	void *lp;
103
104#ifndef MKSH_SMALL
105	if (ALLOC_ISUNALIGNED(ptr))
106		goto fail;
107#endif
108	/* get address of ALLOC_ITEM from user item */
109	/*
110	 * note: the alignment of "ptr" to ALLOC_ITEM is checked
111	 * above; the "void *" gets us rid of a gcc 2.95 warning
112	 */
113	*lpp = (lp = ptr - sizeof(ALLOC_ITEM));
114	/* search for allocation item in group list */
115	while (ap->next != lp)
116		if ((ap = ap->next) == NULL) {
117#ifndef MKSH_SMALL
118 fail:
119#endif
120#ifdef DEBUG
121			internal_warningf("rogue pointer %zX in ap %zX",
122			    (size_t)ptr, (size_t)ap);
123			/* try to get a coredump */
124			abort();
125#else
126			internal_errorf("rogue pointer %zX", (size_t)ptr);
127#endif
128		}
129	return (ap);
130}
131
132void *
133aresize2(void *ptr, size_t fac1, size_t fac2, Area *ap)
134{
135	if (notoktomul(fac1, fac2))
136		internal_errorf(Tintovfl, fac1, '*', fac2);
137	return (aresize(ptr, fac1 * fac2, ap));
138}
139
140void *
141aresize(void *ptr, size_t numb, Area *ap)
142{
143	struct lalloc_common *lp = NULL;
144
145	/* resizing (true) or newly allocating? */
146	if (ptr != NULL) {
147		struct lalloc_common *pp;
148
149		pp = findptr(&lp, ptr, ap);
150		pp->next = lp->next;
151	}
152
153	if (notoktoadd(numb, sizeof(ALLOC_ITEM)) ||
154	    (lp = remalloc(lp, numb + sizeof(ALLOC_ITEM))) == NULL
155#ifndef MKSH_SMALL
156	    || ALLOC_ISUNALIGNED(lp)
157#endif
158	    )
159		internal_errorf(Toomem, numb);
160	/* area pointer and items share struct lalloc_common */
161	lp->next = ap->next;
162	ap->next = lp;
163	/* return user item address */
164	return ((char *)lp + sizeof(ALLOC_ITEM));
165}
166
167void
168afree(void *ptr, Area *ap)
169{
170	if (ptr != NULL) {
171		struct lalloc_common *lp, *pp;
172
173		pp = findptr(&lp, ptr, ap);
174		/* unhook */
175		pp->next = lp->next;
176		/* now free ALLOC_ITEM */
177		free_osimalloc(lp);
178	}
179}
180
181void
182afreeall(Area *ap)
183{
184	struct lalloc_common *lp;
185
186	/* traverse group (linked list) */
187	while ((lp = ap->next) != NULL) {
188		/* make next ALLOC_ITEM head of list */
189		ap->next = lp->next;
190		/* free old head */
191		free_osimalloc(lp);
192	}
193}
194