/*
* Platform-independent routines shared between all PuTTY programs.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <assert.h>
#include "putty.h"
/* ----------------------------------------------------------------------
* String handling routines.
*/
char *dupstr(const char *s)
{
char *p = NULL;
if (s) {
int len = strlen(s);
p = snewn(len + 1, char);
strcpy(p, s);
}
return p;
}
/* Allocate the concatenation of N strings. Terminate arg list with NULL. */
char *dupcat(const char *s1, ...)
{
int len;
char *p, *q, *sn;
va_list ap;
len = strlen(s1);
va_start(ap, s1);
while (1) {
sn = va_arg(ap, char *);
if (!sn)
break;
len += strlen(sn);
}
va_end(ap);
p = snewn(len + 1, char);
strcpy(p, s1);
q = p + strlen(p);
va_start(ap, s1);
while (1) {
sn = va_arg(ap, char *);
if (!sn)
break;
strcpy(q, sn);
q += strlen(q);
}
va_end(ap);
return p;
}
/*
* Do an sprintf(), but into a custom-allocated buffer.
*
* Currently I'm doing this via vsnprintf. This has worked so far,
* but it's not good, because:
*
* - vsnprintf is not available on all platforms. There's an ifdef
* to use `_vsnprintf', which seems to be the local name for it
* on Windows. Other platforms may lack it completely, in which
* case it'll be time to rewrite this function in a totally
* different way.
*
* - technically you can't reuse a va_list like this: it is left
* unspecified whether advancing a va_list pointer modifies its
* value or something it points to, so on some platforms calling
* vsnprintf twice on the same va_list might fail hideously. It
* would be better to use the `va_copy' macro mandated by C99,
* but that too is not yet ubiquitous.
*
* The only `properly' portable solution I can think of is to
* implement my own format string scanner, which figures out an
* upper bound for the length of each formatting directive,
* allocates the buffer as it goes along, and calls sprintf() to
* actually process each directive. If I ever need to actually do
* this, some caveats:
*
* - It's very hard to find a reliable upper bound for
* floating-point values. %f, in particular, when supplied with
* a number near to the upper or lower limit of representable
* numbers, could easily take several hundred characters. It's
* probably feasible to predict this statically using the
* constants in <float.h>, or even to predict it dynamically by
* looking at the exponent of the specific float provided, but
* it won't be fun.
*
* - Don't forget to _check_, after calling sprintf, that it's
* used at most the amount of space we had available.
*
* - Fault any formatting directive we don't fully understand. The
* aim here is to _guarantee_ that we never overflow the buffer,
* because this is a security-critical function. If we see a
* directive we don't know about, we should panic and die rather
* than run any risk.
*/
char *dupprintf(const char *fmt, ...)
{
char *ret;
va_list ap;
va_start(ap, fmt);
ret = dupvprintf(fmt, ap);
va_end(ap);
return ret;
}
char *dupvprintf(const char *fmt, va_list ap)
{
char *buf;
int len, size;
buf = snewn(512, char);
size = 512;
while (1) {
#ifdef _WINDOWS
#define vsnprintf _vsnprintf
#endif
len = vsnprintf(buf, size, fmt, ap);
if (len >= 0 && len < size) {
/* This is the C99-specified criterion for snprintf to have
* been completely successful. */
return buf;
} else if (len > 0) {
/* This is the C99 error condition: the returned length is
* the required buffer size not counting the NUL. */
size = len + 1;
} else {
/* This is the pre-C99 glibc error condition: <0 means the
* buffer wasn't big enough, so we enlarge it a bit and hope. */
size += 512;
}
buf = sresize(buf, size, char);
}
}
/* ----------------------------------------------------------------------
* Base64 encoding routine. This is required in public-key writing
* but also in HTTP proxy handling, so it's centralised here.
*/
void base64_encode_atom(unsigned char *data, int n, char *out)
{
static const char base64_chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
unsigned word;
word = data[0] << 16;
if (n > 1)
word |= data[1] << 8;
if (n > 2)
word |= data[2];
out[0] = base64_chars[(word >> 18) & 0x3F];
out[1] = base64_chars[(word >> 12) & 0x3F];
if (n > 1)
out[2] = base64_chars[(word >> 6) & 0x3F];
else
out[2] = '=';
if (n > 2)
out[3] = base64_chars[word & 0x3F];
else
out[3] = '=';
}
/* ----------------------------------------------------------------------
* Generic routines to deal with send buffers: a linked list of
* smallish blocks, with the operations
*
* - add an arbitrary amount of data to the end of the list
* - remove the first N bytes from the list
* - return a (pointer,length) pair giving some initial data in
* the list, suitable for passing to a send or write system
* call
* - retrieve a larger amount of initial data from the list
* - return the current size of the buffer chain in bytes
*/
#define BUFFER_GRANULE 512
struct bufchain_granule {
struct bufchain_granule *next;
int buflen, bufpos;
char buf[BUFFER_GRANULE];
};
void bufchain_init(bufchain *ch)
{
ch->head = ch->tail = NULL;
ch->buffersize = 0;
}
void bufchain_clear(bufchain *ch)
{
struct bufchain_granule *b;
while (ch->head) {
b = ch->head;
ch->head = ch->head->next;
sfree(b);
}
ch->tail = NULL;
ch->buffersize = 0;
}
int bufchain_size(bufchain *ch)
{
return ch->buffersize;
}
void bufchain_add(bufchain *ch, const void *data, int len)
{
const char *buf = (const char *)data;
if (len == 0) return;
ch->buffersize += len;
if (ch->tail && ch->tail->buflen < BUFFER_GRANULE) {
int copylen = min(len, BUFFER_GRANULE - ch->tail->buflen);
memcpy(ch->tail->buf + ch->tail->buflen, buf, copylen);
buf += copylen;
len -= copylen;
ch->tail->buflen += copylen;
}
while (len > 0) {
int grainlen = min(len, BUFFER_GRANULE);
struct bufchain_granule *newbuf;
newbuf = snew(struct bufchain_granule);
newbuf->bufpos = 0;
newbuf->buflen = grainlen;
memcpy(newbuf->buf, buf, grainlen);
buf += grainlen;
len -= grainlen;
if (ch->tail)
ch->tail->next = newbuf;
else
ch->head = ch->tail = newbuf;
newbuf->next = NULL;
ch->tail = newbuf;
}
}
void bufchain_consume(bufchain *ch, int len)
{
struct bufchain_granule *tmp;
assert(ch->buffersize >= len);
while (len > 0) {
int remlen = len;
assert(ch->head != NULL);
if (remlen >= ch->head->buflen - ch->head->bufpos) {
remlen = ch->head->buflen - ch->head->bufpos;
tmp = ch->head;
ch->head = tmp->next;
sfree(tmp);
if (!ch->head)
ch->tail = NULL;
} else
ch->head->bufpos += remlen;
ch->buffersize -= remlen;
len -= remlen;
}
}
void bufchain_prefix(bufchain *ch, void **data, int *len)
{
*len = ch->head->buflen - ch->head->bufpos;
*data = ch->head->buf + ch->head->bufpos;
}
void bufchain_fetch(bufchain *ch, void *data, int len)
{
struct bufchain_granule *tmp;
char *data_c = (char *)data;
tmp = ch->head;
assert(ch->buffersize >= len);
while (len > 0) {
int remlen = len;
assert(tmp != NULL);
if (remlen >= tmp->buflen - tmp->bufpos)
remlen = tmp->buflen - tmp->bufpos;
memcpy(data_c, tmp->buf + tmp->bufpos, remlen);
tmp = tmp->next;
len -= remlen;
data_c += remlen;
}
}
/* ----------------------------------------------------------------------
* 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
void *minefield_c_malloc(size_t size);
void minefield_c_free(void *p);
void *minefield_c_realloc(void *p, size_t size);
#endif
#ifdef MALLOC_LOG
static FILE *fp = NULL;
static char *mlog_file = NULL;
static int mlog_line = 0;
void mlog(char *file, int line)
{
mlog_file = file;
mlog_line = 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) {
char str[200];
#ifdef MALLOC_LOG
sprintf(str, "Out of memory! (%s:%d, size=%d)",
mlog_file, mlog_line, size);
fprintf(fp, "*** %s\n", str);
fclose(fp);
#else
strcpy(str, "Out of memory!");
#endif
modalfatalbox(str);
}
#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) {
char str[200];
#ifdef MALLOC_LOG
sprintf(str, "Out of memory! (%s:%d, size=%d)",
mlog_file, mlog_line, size);
fprintf(fp, "*** %s\n", str);
fclose(fp);
#else
strcpy(str, "Out of memory!");
#endif
modalfatalbox(str);
}
#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
}
/* ----------------------------------------------------------------------
* Debugging routines.
*/
#ifdef DEBUG
extern void dputs(char *); /* defined in per-platform *misc.c */
void debug_printf(char *fmt, ...)
{
char *buf;
va_list ap;
va_start(ap, fmt);
buf = dupvprintf(fmt, ap);
dputs(buf);
sfree(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;
debug_printf("\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)
debug_printf("%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 {
debug_printf("%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';
debug_printf("%*s%s\n", (16 - i) * 3 + 2, "", foo);
}
}
#endif /* def DEBUG */