X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/5b80d07f712ff90cfae4c89084e25eb90dd2e510..d57f70afa40c24426e5f936c86f7640801d43f7a:/misc.c

diff --git a/misc.c b/misc.c
index e06ced64..59e91f2f 100644
--- a/misc.c
+++ b/misc.c
@@ -1,40 +1,412 @@
-#include <windows.h>
-#ifndef AUTO_WINSOCK
-#ifdef WINSOCK_TWO
-#include <winsock2.h>
-#else
-#include <winsock.h>
-#endif
-#endif
+/*
+ * 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"
 
-/* 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. Of course we can also
- * put trace printouts in, if we need to. */
+/*
+ * Parse a string block size specification. This is approximately a
+ * subset of the block size specs supported by GNU fileutils:
+ *  "nk" = n kilobytes
+ *  "nM" = n megabytes
+ *  "nG" = n gigabytes
+ * All numbers are decimal, and suffixes refer to powers of two.
+ * Case-insensitive.
+ */
+unsigned long parse_blocksize(const char *bs)
+{
+    char *suf;
+    unsigned long r = strtoul(bs, &suf, 10);
+    if (*suf != '\0') {
+	while (isspace(*suf)) suf++;
+	switch (*suf) {
+	  case 'k': case 'K':
+	    r *= 1024ul;
+	    break;
+	  case 'm': case 'M':
+	    r *= 1024ul * 1024ul;
+	    break;
+	  case 'g': case 'G':
+	    r *= 1024ul * 1024ul * 1024ul;
+	    break;
+	  case '\0':
+	  default:
+	    break;
+	}
+    }
+    return r;
+}
+
+/* ----------------------------------------------------------------------
+ * 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);
+    }
+}
+
+/*
+ * Read an entire line of text from a file. Return a buffer
+ * malloced to be as big as necessary (caller must free).
+ */
+char *fgetline(FILE *fp)
+{
+    char *ret = snewn(512, char);
+    int size = 512, len = 0;
+    while (fgets(ret + len, size - len, fp)) {
+	len += strlen(ret + len);
+	if (ret[len-1] == '\n')
+	    break;		       /* got a newline, we're done */
+	size = len + 512;
+	ret = sresize(ret, size, char);
+    }
+    if (len == 0) {		       /* first fgets returned NULL */
+	sfree(ret);
+	return NULL;
+    }
+    ret[len] = '\0';
+    return ret;
+}
+
+/* ----------------------------------------------------------------------
+ * 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;
 
-void mlog(char *file, int line) {
+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);
+	fprintf(fp, "%s:%d: ", file, line);
 }
 #endif
 
-void *safemalloc(size_t size) {
-    void *p = malloc (size);
+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);
+	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)
@@ -43,16 +415,33 @@ void *safemalloc(size_t size) {
     return p;
 }
 
-void *saferealloc(void *ptr, size_t size) {
+void *saferealloc(void *ptr, size_t size)
+{
     void *p;
-    if (!ptr)
-	p = malloc (size);
-    else
-	p = realloc (ptr, size);
+    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);
+	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)
@@ -61,16 +450,78 @@ void *saferealloc(void *ptr, size_t size) {
     return p;
 }
 
-void safefree(void *ptr) {
+void safefree(void *ptr)
+{
     if (ptr) {
 #ifdef MALLOC_LOG
 	if (fp)
 	    fprintf(fp, "free(%p)\n", ptr);
 #endif
-	free (ptr);
+#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 */