[u/mdw/putty] / misc.c

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include "putty.h"

/*
 * My own versions of malloc, realloc and free. Because I want
 * malloc and realloc to bomb out and exit the program if they run
 * out of memory, realloc to reliably call malloc if passed a NULL
 * pointer, and free to reliably do nothing if passed a NULL
 * pointer. We can also put trace printouts in, if we need to; and
 * we can also replace the allocator with an ElectricFence-like
 * one.
 */

#ifdef MINEFIELD
/*
 * Minefield - a Windows equivalent for Electric Fence
 */

#define PAGESIZE 4096

/*
 * Design:
 * 
 * We start by reserving as much virtual address space as Windows
 * will sensibly (or not sensibly) let us have. We flag it all as
 * invalid memory.
 * 
 * Any allocation attempt is satisfied by committing one or more
 * pages, with an uncommitted page on either side. The returned
 * memory region is jammed up against the _end_ of the pages.
 * 
 * Freeing anything causes instantaneous decommitment of the pages
 * involved, so stale pointers are caught as soon as possible.
 */

static int minefield_initialised = 0;
static void *minefield_region = NULL;
static long minefield_size = 0;
static long minefield_npages = 0;
static long minefield_curpos = 0;
static unsigned short *minefield_admin = NULL;
static void *minefield_pages = NULL;

static void minefield_admin_hide(int hide) {
    int access = hide ? PAGE_NOACCESS : PAGE_READWRITE;
    VirtualProtect(minefield_admin, minefield_npages*2, access, NULL);
}

static void minefield_init(void) {
    int size;
    int admin_size;
    int i;

    for (size = 0x40000000; size > 0; size = ((size >> 3) * 7) &~ 0xFFF) {
        minefield_region = VirtualAlloc(NULL, size,
                                        MEM_RESERVE, PAGE_NOACCESS);
        if (minefield_region)
            break;
    }
    minefield_size = size;

    /*
     * Firstly, allocate a section of that to be the admin block.
     * We'll need a two-byte field for each page.
     */
    minefield_admin = minefield_region;
    minefield_npages = minefield_size / PAGESIZE;
    admin_size = (minefield_npages * 2 + PAGESIZE-1) &~ (PAGESIZE-1);
    minefield_npages = (minefield_size - admin_size) / PAGESIZE;
    minefield_pages = (char *)minefield_region + admin_size;

    /*
     * Commit the admin region.
     */
    VirtualAlloc(minefield_admin, minefield_npages * 2,
                 MEM_COMMIT, PAGE_READWRITE);

    /*
     * Mark all pages as unused (0xFFFF).
     */
    for (i = 0; i < minefield_npages; i++)
        minefield_admin[i] = 0xFFFF;

    /*
     * Hide the admin region.
     */
    minefield_admin_hide(1);

    minefield_initialised = 1;
}

static void minefield_bomb(void) {
    div(1, *(int*)minefield_pages);
}

static void *minefield_alloc(int size) {
    int npages;
    int pos, lim, region_end, region_start;
    int start;
    int i;

    npages = (size + PAGESIZE-1) / PAGESIZE;

    minefield_admin_hide(0);

    /*
     * Search from current position until we find a contiguous
     * bunch of npages+2 unused pages.
     */
    pos = minefield_curpos;
    lim = minefield_npages;
    while (1) {
        /* Skip over used pages. */
        while (pos < lim && minefield_admin[pos] != 0xFFFF)
            pos++;
        /* Count unused pages. */
        start = pos;
        while (pos < lim && pos - start < npages+2 &&
               minefield_admin[pos] == 0xFFFF)
            pos++;
        if (pos - start == npages+2)
            break;
        /* If we've reached the limit, reset the limit or stop. */
        if (pos >= lim) {
            if (lim == minefield_npages) {
                /* go round and start again at zero */
                lim = minefield_curpos;
                pos = 0;
            } else {
                minefield_admin_hide(1);
                return NULL;
            }
        }
    }

    minefield_curpos = pos-1;

    /*
     * We have npages+2 unused pages starting at start. We leave
     * the first and last of these alone and use the rest.
     */
    region_end = (start + npages+1) * PAGESIZE;
    region_start = region_end - size;
    /* FIXME: could align here if we wanted */

    /*
     * Update the admin region.
     */
    for (i = start + 2; i < start + npages-1; i++)
        minefield_admin[i] = 0xFFFE;   /* used but no region starts here */
    minefield_admin[start+1] = region_start % PAGESIZE;

    minefield_admin_hide(1);

    VirtualAlloc((char *)minefield_pages + region_start, size,
                 MEM_COMMIT, PAGE_READWRITE);
    return (char *)minefield_pages + region_start;
}

static void minefield_free(void *ptr) {
    int region_start, i, j;

    minefield_admin_hide(0);

    region_start = (char *)ptr - (char *)minefield_pages;
    i = region_start / PAGESIZE;
    if (i < 0 || i >= minefield_npages ||
        minefield_admin[i] != region_start % PAGESIZE)
        minefield_bomb();
    for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++) {
        minefield_admin[j] = 0xFFFF;
    }

    VirtualFree(ptr, j*PAGESIZE - region_start, MEM_DECOMMIT);

    minefield_admin_hide(1);
}

static int minefield_get_size(void *ptr) {
    int region_start, i, j;

    minefield_admin_hide(0);

    region_start = (char *)ptr - (char *)minefield_pages;
    i = region_start / PAGESIZE;
    if (i < 0 || i >= minefield_npages ||
        minefield_admin[i] != region_start % PAGESIZE)
        minefield_bomb();
    for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++);

    minefield_admin_hide(1);

    return j*PAGESIZE - region_start;
}

static void *minefield_c_malloc(size_t size) {
    if (!minefield_initialised) minefield_init();
    return minefield_alloc(size);
}

static void minefield_c_free(void *p) {
    if (!minefield_initialised) minefield_init();
    minefield_free(p);
}

/*
 * realloc _always_ moves the chunk, for rapid detection of code
 * that assumes it won't.
 */
static void *minefield_c_realloc(void *p, size_t size) {
    size_t oldsize;
    void *q;
    if (!minefield_initialised) minefield_init();
    q = minefield_alloc(size);
    oldsize = minefield_get_size(p);
    memcpy(q, p, (oldsize < size ? oldsize : size));
    minefield_free(p);
    return q;
}

#endif /* MINEFIELD */

#ifdef MALLOC_LOG
static FILE *fp = NULL;

void mlog(char *file, int line) {
    if (!fp) {
	fp = fopen("putty_mem.log", "w");
	setvbuf(fp, NULL, _IONBF, BUFSIZ);
    }
    if (fp)
	fprintf (fp, "%s:%d: ", file, line);
}
#endif

void *safemalloc(size_t size) {
    void *p;
#ifdef MINEFIELD
    p = minefield_c_malloc (size);
#else
    p = malloc (size);
#endif
    if (!p) {
	MessageBox(NULL, "Out of memory!", "PuTTY Fatal Error",
		   MB_SYSTEMMODAL | MB_ICONERROR | MB_OK);
	exit(1);
    }
#ifdef MALLOC_LOG
    if (fp)
	fprintf(fp, "malloc(%d) returns %p\n", size, p);
#endif
    return p;
}

void *saferealloc(void *ptr, size_t size) {
    void *p;
    if (!ptr) {
#ifdef MINEFIELD
	p = minefield_c_malloc (size);
#else
	p = malloc (size);
#endif
    } else {
#ifdef MINEFIELD
	p = minefield_c_realloc (ptr, size);
#else
	p = realloc (ptr, size);
#endif
    }
    if (!p) {
	MessageBox(NULL, "Out of memory!", "PuTTY Fatal Error",
		   MB_SYSTEMMODAL | MB_ICONERROR | MB_OK);
	exit(1);
    }
#ifdef MALLOC_LOG
    if (fp)
	fprintf(fp, "realloc(%p,%d) returns %p\n", ptr, size, p);
#endif
    return p;
}

void safefree(void *ptr) {
    if (ptr) {
#ifdef MALLOC_LOG
	if (fp)
	    fprintf(fp, "free(%p)\n", ptr);
#endif
#ifdef MINEFIELD
	minefield_c_free (ptr);
#else
	free (ptr);
#endif
    }
#ifdef MALLOC_LOG
    else if (fp)
	fprintf(fp, "freeing null pointer - no action taken\n");
#endif
}

#ifdef DEBUG
static FILE *debug_fp = NULL;
static int debug_got_console = 0;

static void dputs (char *buf) {
    DWORD dw;

    if (!debug_got_console) {
	AllocConsole();
	debug_got_console = 1;
    }
    if (!debug_fp) {
	debug_fp = fopen("debug.log", "w");
    }

    WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), buf, strlen(buf), &dw, NULL);
    fputs(buf, debug_fp);
    fflush(debug_fp);
}


void dprintf(char *fmt, ...) {
    char buf[2048];
    va_list ap;

    va_start(ap, fmt);
    vsprintf(buf, fmt, ap);
    dputs (buf);
    va_end(ap);
}


void debug_memdump (void *buf, int len, int L) {
    int i;
    unsigned char *p = buf;
    char foo[17];
    if (L) {
	int delta;
        dprintf ("\t%d (0x%x) bytes:\n", len, len);
	delta = 15 & (int) p;
	p -= delta;
	len += delta;
    }
    for (; 0 < len; p += 16, len -= 16) {
	dputs ("  ");
	if (L) dprintf ("%p: ", p);
	strcpy(foo, "................");   /* sixteen dots */
	for (i = 0; i < 16 && i < len; ++i) {
	    if (&p[i] < (unsigned char *) buf) {
		dputs ("   "); /* 3 spaces */
		foo[i] = ' ';
	    } else {
		dprintf (
		    "%c%02.2x",
		    &p[i] != (unsigned char *) buf && i % 4 ? '.' : ' ',
		    p[i]
		);
		if (p[i] >= ' ' && p[i] <= '~')
		    foo[i] = (char)p[i];
	    }
	}
	foo[i] = '\0';
	dprintf("%*s%s\n", (16-i)*3+2, "", foo);
    }
}

#endif /* def DEBUG */
Commit	Line	Data
374330e2	1	#include <windows.h>
	2	#include <stdio.h>
	3	#include <stdlib.h>
	4	#include "putty.h"
	5
b191636d	6	/*
	7	* My own versions of malloc, realloc and free. Because I want
	8	* malloc and realloc to bomb out and exit the program if they run
	9	* out of memory, realloc to reliably call malloc if passed a NULL
	10	* pointer, and free to reliably do nothing if passed a NULL
	11	* pointer. We can also put trace printouts in, if we need to; and
	12	* we can also replace the allocator with an ElectricFence-like
	13	* one.
	14	*/
	15
	16	#ifdef MINEFIELD
	17	/*
	18	* Minefield - a Windows equivalent for Electric Fence
	19	*/
	20
	21	#define PAGESIZE 4096
	22
	23	/*
	24	* Design:
	25	*
	26	* We start by reserving as much virtual address space as Windows
	27	* will sensibly (or not sensibly) let us have. We flag it all as
	28	* invalid memory.
	29	*
	30	* Any allocation attempt is satisfied by committing one or more
	31	* pages, with an uncommitted page on either side. The returned
	32	* memory region is jammed up against the _end_ of the pages.
	33	*
	34	* Freeing anything causes instantaneous decommitment of the pages
	35	* involved, so stale pointers are caught as soon as possible.
	36	*/
	37
	38	static int minefield_initialised = 0;
	39	static void *minefield_region = NULL;
	40	static long minefield_size = 0;
	41	static long minefield_npages = 0;
	42	static long minefield_curpos = 0;
	43	static unsigned short *minefield_admin = NULL;
	44	static void *minefield_pages = NULL;
	45
	46	static void minefield_admin_hide(int hide) {
	47	int access = hide ? PAGE_NOACCESS : PAGE_READWRITE;
	48	VirtualProtect(minefield_admin, minefield_npages*2, access, NULL);
	49	}
	50
	51	static void minefield_init(void) {
	52	int size;
	53	int admin_size;
	54	int i;
	55
	56	for (size = 0x40000000; size > 0; size = ((size >> 3) * 7) &~ 0xFFF) {
b191636d	57	minefield_region = VirtualAlloc(NULL, size,
	58	MEM_RESERVE, PAGE_NOACCESS);
	59	if (minefield_region)
	60	break;
	61	}
	62	minefield_size = size;
b191636d	63
	64	/*
	65	* Firstly, allocate a section of that to be the admin block.
	66	* We'll need a two-byte field for each page.
	67	*/
	68	minefield_admin = minefield_region;
	69	minefield_npages = minefield_size / PAGESIZE;
	70	admin_size = (minefield_npages * 2 + PAGESIZE-1) &~ (PAGESIZE-1);
	71	minefield_npages = (minefield_size - admin_size) / PAGESIZE;
	72	minefield_pages = (char *)minefield_region + admin_size;
b191636d	73
	74	/*
	75	* Commit the admin region.
	76	*/
	77	VirtualAlloc(minefield_admin, minefield_npages * 2,
	78	MEM_COMMIT, PAGE_READWRITE);
	79
	80	/*
	81	* Mark all pages as unused (0xFFFF).
	82	*/
	83	for (i = 0; i < minefield_npages; i++)
	84	minefield_admin[i] = 0xFFFF;
	85
	86	/*
	87	* Hide the admin region.
	88	*/
	89	minefield_admin_hide(1);
	90
	91	minefield_initialised = 1;
	92	}
	93
	94	static void minefield_bomb(void) {
	95	div(1, (int)minefield_pages);
	96	}
	97
	98	static void *minefield_alloc(int size) {
	99	int npages;
	100	int pos, lim, region_end, region_start;
	101	int start;
	102	int i;
	103
	104	npages = (size + PAGESIZE-1) / PAGESIZE;
	105
	106	minefield_admin_hide(0);
	107
	108	/*
	109	* Search from current position until we find a contiguous
	110	* bunch of npages+2 unused pages.
	111	*/
	112	pos = minefield_curpos;
	113	lim = minefield_npages;
	114	while (1) {
	115	/* Skip over used pages. */
	116	while (pos < lim && minefield_admin[pos] != 0xFFFF)
	117	pos++;
	118	/* Count unused pages. */
	119	start = pos;
	120	while (pos < lim && pos - start < npages+2 &&
	121	minefield_admin[pos] == 0xFFFF)
	122	pos++;
	123	if (pos - start == npages+2)
	124	break;
	125	/* If we've reached the limit, reset the limit or stop. */
	126	if (pos >= lim) {
	127	if (lim == minefield_npages) {
	128	/* go round and start again at zero */
	129	lim = minefield_curpos;
	130	pos = 0;
	131	} else {
	132	minefield_admin_hide(1);
	133	return NULL;
	134	}
	135	}
	136	}
137
138	minefield_curpos = pos-1;
139
140	/*
141	* We have npages+2 unused pages starting at start. We leave
142	* the first and last of these alone and use the rest.
143	*/
144	region_end = (start + npages+1) * PAGESIZE;
145	region_start = region_end - size;
146	/* FIXME: could align here if we wanted */
147
148	/*
149	* Update the admin region.
150	*/
151	for (i = start + 2; i < start + npages-1; i++)
152	minefield_admin[i] = 0xFFFE; /* used but no region starts here */
153	minefield_admin[start+1] = region_start % PAGESIZE;
154
155	minefield_admin_hide(1);
156
157	VirtualAlloc((char *)minefield_pages + region_start, size,
158	MEM_COMMIT, PAGE_READWRITE);
159	return (char *)minefield_pages + region_start;
160	}
161
162	static void minefield_free(void *ptr) {
163	int region_start, i, j;
164
165	minefield_admin_hide(0);
166
167	region_start = (char )ptr - (char )minefield_pages;
168	i = region_start / PAGESIZE;
169	if (i < 0 \|\| i >= minefield_npages \|\|
170	minefield_admin[i] != region_start % PAGESIZE)
171	minefield_bomb();
172	for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++) {
173	minefield_admin[j] = 0xFFFF;
174	}
175
176	VirtualFree(ptr, j*PAGESIZE - region_start, MEM_DECOMMIT);
177
178	minefield_admin_hide(1);
179	}
180
181	static int minefield_get_size(void *ptr) {
182	int region_start, i, j;
183
184	minefield_admin_hide(0);
185
186	region_start = (char )ptr - (char )minefield_pages;
187	i = region_start / PAGESIZE;
188	if (i < 0 \|\| i >= minefield_npages \|\|
189	minefield_admin[i] != region_start % PAGESIZE)
190	minefield_bomb();
191	for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++);
192
193	minefield_admin_hide(1);
194
195	return j*PAGESIZE - region_start;
196	}
197
198	static void *minefield_c_malloc(size_t size) {
199	if (!minefield_initialised) minefield_init();
200	return minefield_alloc(size);
201	}
202
203	static void minefield_c_free(void *p) {
204	if (!minefield_initialised) minefield_init();
205	minefield_free(p);
206	}
207
208	/*
209	* realloc _always_ moves the chunk, for rapid detection of code
210	* that assumes it won't.
211	*/
212	static void minefield_c_realloc(void p, size_t size) {
213	size_t oldsize;
214	void *q;
215	if (!minefield_initialised) minefield_init();
216	q = minefield_alloc(size);
217	oldsize = minefield_get_size(p);
218	memcpy(q, p, (oldsize < size ? oldsize : size));
219	minefield_free(p);
220	return q;
221	}
222
223	#endif /* MINEFIELD */
374330e2	224
	225	#ifdef MALLOC_LOG
	226	static FILE *fp = NULL;
	227
	228	void mlog(char *file, int line) {
c662dbc0	229	if (!fp) {
374330e2	230	fp = fopen("putty_mem.log", "w");
c662dbc0	231	setvbuf(fp, NULL, _IONBF, BUFSIZ);
c662dbc0	232	}
374330e2	233	if (fp)
	234	fprintf (fp, "%s:%d: ", file, line);
	235	}
	236	#endif
	237
	238	void *safemalloc(size_t size) {
b191636d	239	void *p;
	240	#ifdef MINEFIELD
	241	p = minefield_c_malloc (size);
	242	#else
	243	p = malloc (size);
	244	#endif
374330e2	245	if (!p) {
	246	MessageBox(NULL, "Out of memory!", "PuTTY Fatal Error",
	247	MB_SYSTEMMODAL \| MB_ICONERROR \| MB_OK);
	248	exit(1);
	249	}
	250	#ifdef MALLOC_LOG
	251	if (fp)
	252	fprintf(fp, "malloc(%d) returns %p\n", size, p);
	253	#endif
	254	return p;
	255	}
	256
	257	void saferealloc(void ptr, size_t size) {
	258	void *p;
b191636d	259	if (!ptr) {
	260	#ifdef MINEFIELD
	261	p = minefield_c_malloc (size);
	262	#else
374330e2	263	p = malloc (size);
b191636d	264	#endif
	265	} else {
	266	#ifdef MINEFIELD
	267	p = minefield_c_realloc (ptr, size);
	268	#else
374330e2	269	p = realloc (ptr, size);
b191636d	270	#endif
b191636d	271	}
374330e2	272	if (!p) {
	273	MessageBox(NULL, "Out of memory!", "PuTTY Fatal Error",
	274	MB_SYSTEMMODAL \| MB_ICONERROR \| MB_OK);
	275	exit(1);
	276	}
	277	#ifdef MALLOC_LOG
	278	if (fp)
	279	fprintf(fp, "realloc(%p,%d) returns %p\n", ptr, size, p);
	280	#endif
	281	return p;
	282	}
	283
	284	void safefree(void *ptr) {
	285	if (ptr) {
	286	#ifdef MALLOC_LOG
	287	if (fp)
	288	fprintf(fp, "free(%p)\n", ptr);
	289	#endif
b191636d	290	#ifdef MINEFIELD
	291	minefield_c_free (ptr);
	292	#else
374330e2	293	free (ptr);
b191636d	294	#endif
374330e2	295	}
	296	#ifdef MALLOC_LOG
	297	else if (fp)
	298	fprintf(fp, "freeing null pointer - no action taken\n");
	299	#endif
	300	}
c82bda52	301
	302	#ifdef DEBUG
	303	static FILE *debug_fp = NULL;
	304	static int debug_got_console = 0;
	305
db9c0f86	306	static void dputs (char *buf) {
c82bda52	307	DWORD dw;
c82bda52	308
	309	if (!debug_got_console) {
	310	AllocConsole();
	311	debug_got_console = 1;
	312	}
	313	if (!debug_fp) {
	314	debug_fp = fopen("debug.log", "w");
	315	}
	316
c82bda52	317	WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), buf, strlen(buf), &dw, NULL);
	318	fputs(buf, debug_fp);
	319	fflush(debug_fp);
db9c0f86	320	}
	321
	322
	323	void dprintf(char *fmt, ...) {
	324	char buf[2048];
	325	va_list ap;
	326
	327	va_start(ap, fmt);
	328	vsprintf(buf, fmt, ap);
	329	dputs (buf);
c82bda52	330	va_end(ap);
c82bda52	331	}
db9c0f86	332
	333
	334	void debug_memdump (void *buf, int len, int L) {
	335	int i;
	336	unsigned char *p = buf;
765c4200	337	char foo[17];
db9c0f86	338	if (L) {
	339	int delta;
	340	dprintf ("\t%d (0x%x) bytes:\n", len, len);
	341	delta = 15 & (int) p;
	342	p -= delta;
	343	len += delta;
	344	}
	345	for (; 0 < len; p += 16, len -= 16) {
765c4200	346	dputs (" ");
	347	if (L) dprintf ("%p: ", p);
	348	strcpy(foo, "................"); /* sixteen dots */
db9c0f86	349	for (i = 0; i < 16 && i < len; ++i) {
	350	if (&p[i] < (unsigned char *) buf) {
	351	dputs (" "); /* 3 spaces */
765c4200	352	foo[i] = ' ';
db9c0f86	353	} else {
	354	dprintf (
	355	"%c%02.2x",
	356	&p[i] != (unsigned char *) buf && i % 4 ? '.' : ' ',
	357	p[i]
	358	);
765c4200	359	if (p[i] >= ' ' && p[i] <= '~')
765c4200	360	foo[i] = (char)p[i];
db9c0f86	361	}
db9c0f86	362	}
765c4200	363	foo[i] = '\0';
765c4200	364	dprintf("%s%s\n", (16-i)3+2, "", foo);
db9c0f86	365	}
	366	}
	367
	368	#endif /* def DEBUG */
	369