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[tor-commits] [tor/release-0.3.5] Merge branch 'ticket30561_029' into ticket30561_035
commit 8f0b29961eb4b9965f22bbcabdc0aa0354c19a4a
Merge: e5deb2bbc 0e0cf4abd
Author: Nick Mathewson <nickm@xxxxxxxxxxxxxx>
Date: Wed May 29 09:43:20 2019 -0400
Merge branch 'ticket30561_029' into ticket30561_035
changes/bug30561 | 6 ++++++
src/lib/string/printf.c | 16 +++++++++++++---
2 files changed, 19 insertions(+), 3 deletions(-)
diff --cc src/lib/string/printf.c
index 415d4ac4a,000000000..a5cb71ce0
mode 100644,000000..100644
--- a/src/lib/string/printf.c
+++ b/src/lib/string/printf.c
@@@ -1,157 -1,0 +1,167 @@@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file printf.c
+ * \brief Compatibility wrappers around snprintf and its friends
+ **/
+
+#include "lib/string/printf.h"
+#include "lib/err/torerr.h"
+#include "lib/cc/torint.h"
+#include "lib/malloc/malloc.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+/** Replacement for snprintf. Differs from platform snprintf in two
+ * ways: First, always NUL-terminates its output. Second, always
+ * returns -1 if the result is truncated. (Note that this return
+ * behavior does <i>not</i> conform to C99; it just happens to be
+ * easier to emulate "return -1" with conformant implementations than
+ * it is to emulate "return number that would be written" with
+ * non-conformant implementations.) */
+int
+tor_snprintf(char *str, size_t size, const char *format, ...)
+{
+ va_list ap;
+ int r;
+ va_start(ap,format);
+ r = tor_vsnprintf(str,size,format,ap);
+ va_end(ap);
+ return r;
+}
+
+/** Replacement for vsnprintf; behavior differs as tor_snprintf differs from
+ * snprintf.
+ */
+int
+tor_vsnprintf(char *str, size_t size, const char *format, va_list args)
+{
+ int r;
+ if (size == 0)
+ return -1; /* no place for the NUL */
+ if (size > SIZE_T_CEILING)
+ return -1;
+#ifdef _WIN32
+ r = _vsnprintf(str, size, format, args);
+#else
+ r = vsnprintf(str, size, format, args);
+#endif
+ str[size-1] = '\0';
+ if (r < 0 || r >= (ssize_t)size)
+ return -1;
+ return r;
+}
+
+/**
+ * Portable asprintf implementation. Does a printf() into a newly malloc'd
+ * string. Sets *<b>strp</b> to this string, and returns its length (not
+ * including the terminating NUL character).
+ *
+ * You can treat this function as if its implementation were something like
+ <pre>
+ char buf[_INFINITY_];
+ tor_snprintf(buf, sizeof(buf), fmt, args);
+ *strp = tor_strdup(buf);
+ return strlen(*strp):
+ </pre>
+ * Where _INFINITY_ is an imaginary constant so big that any string can fit
+ * into it.
+ */
+int
+tor_asprintf(char **strp, const char *fmt, ...)
+{
+ int r;
+ va_list args;
+ va_start(args, fmt);
+ r = tor_vasprintf(strp, fmt, args);
+ va_end(args);
+ if (!*strp || r < 0) {
+ /* LCOV_EXCL_START */
+ raw_assert_unreached_msg("Internal error in asprintf");
+ /* LCOV_EXCL_STOP */
+ }
+ return r;
+}
+
+/**
+ * Portable vasprintf implementation. Does a printf() into a newly malloc'd
+ * string. Differs from regular vasprintf in the same ways that
+ * tor_asprintf() differs from regular asprintf.
+ */
+int
+tor_vasprintf(char **strp, const char *fmt, va_list args)
+{
+ /* use a temporary variable in case *strp is in args. */
+ char *strp_tmp=NULL;
+#ifdef HAVE_VASPRINTF
+ /* If the platform gives us one, use it. */
+ int r = vasprintf(&strp_tmp, fmt, args);
+ if (r < 0)
+ *strp = NULL; // LCOV_EXCL_LINE -- no cross-platform way to force this
+ else
+ *strp = strp_tmp;
+ return r;
+#elif defined(HAVE__VSCPRINTF)
+ /* On Windows, _vsnprintf won't tell us the length of the string if it
+ * overflows, so we need to use _vcsprintf to tell how much to allocate */
+ int len, r;
+ va_list tmp_args;
+ va_copy(tmp_args, args);
+ len = _vscprintf(fmt, tmp_args);
+ va_end(tmp_args);
+ if (len < 0) {
+ *strp = NULL;
+ return -1;
+ }
+ strp_tmp = tor_malloc(len + 1);
+ r = _vsnprintf(strp_tmp, len+1, fmt, args);
+ if (r != len) {
+ tor_free(strp_tmp);
+ *strp = NULL;
+ return -1;
+ }
+ *strp = strp_tmp;
+ return len;
+#else
+ /* Everywhere else, we have a decent vsnprintf that tells us how many
+ * characters we need. We give it a try on a short buffer first, since
+ * it might be nice to avoid the second vsnprintf call.
+ */
++ /* XXXX This code spent a number of years broken (see bug 30651). It is
++ * possible that no Tor users actually run on systems without vasprintf() or
++ * _vscprintf(). If so, we should consider removing this code. */
+ char buf[128];
+ int len, r;
+ va_list tmp_args;
+ va_copy(tmp_args, args);
- /* vsnprintf() was properly checked but tor_vsnprintf() available so
- * why not use it? */
- len = tor_vsnprintf(buf, sizeof(buf), fmt, tmp_args);
++ /* Use vsnprintf to retrieve needed length. tor_vsnprintf() is not an
++ * option here because it will simply return -1 if buf is not large enough
++ * to hold the complete string.
++ */
++ len = vsnprintf(buf, sizeof(buf), fmt, tmp_args);
+ va_end(tmp_args);
++ buf[sizeof(buf) - 1] = '\0';
++ if (len < 0) {
++ *strp = NULL;
++ return -1;
++ }
+ if (len < (int)sizeof(buf)) {
+ *strp = tor_strdup(buf);
+ return len;
+ }
+ strp_tmp = tor_malloc(len+1);
+ /* use of tor_vsnprintf() will ensure string is null terminated */
+ r = tor_vsnprintf(strp_tmp, len+1, fmt, args);
+ if (r != len) {
+ tor_free(strp_tmp);
+ *strp = NULL;
+ return -1;
+ }
+ *strp = strp_tmp;
+ return len;
+#endif /* defined(HAVE_VASPRINTF) || ... */
+}
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