When checking pcap.h, make sure we look in ${PCAP_INCLUDE_DIRS}.

[tcpdump] / netdissect-stdinc.h

diff --git a/netdissect-stdinc.h b/netdissect-stdinc.h
index c6e1c2c8df94e153a3524ee409da13b95e4d08ab..d78b66395f1b2c515afeae78dd2738f36060b1aa 100644 (file)
--- a/netdissect-stdinc.h
+++ b/netdissect-stdinc.h
@@ -41,6 +41,10 @@
 
 #include <errno.h>
 
+#include "compiler-tests.h"
+
+#include "varattrs.h"
+
 /*
  * Get the C99 types, and the PRI[doux]64 format strings, defined.
  */
@@ -205,12 +209,23 @@
 #endif
 
 #ifdef _MSC_VER
-#define stat _stat
-#define open _open
-#define fstat _fstat
-#define read _read
-#define close _close
-#define O_RDONLY _O_RDONLY
+  #define stat _stat
+  #define strdup _strdup
+  #define open _open
+  #define fstat _fstat
+  #define read _read
+  #define close _close
+  #define O_RDONLY _O_RDONLY
+
+  /*
+   * If <crtdbg.h> has been included, and _DEBUG is defined, and
+   * __STDC__ is zero, <crtdbg.h> will define strdup() to call
+   * _strdup_dbg().  So if it's already defined, don't redefine
+   * it.
+   */
+  #ifndef strdup
+    #define strdup _strdup
+  #endif
 #endif  /* _MSC_VER */
 
 /*
@@ -273,46 +288,37 @@ typedef char* caddr_t;
 
 #endif /* _WIN32 */
 
-#ifndef HAVE___ATTRIBUTE__
-#define __attribute__(x)
-#endif
+/*
+ * Function attributes, for various compilers.
+ */
+#include "funcattrs.h"
 
 /*
- * Used to declare a structure unaligned, so that the C compiler,
- * if necessary, generates code that doesn't assume alignment.
- * This is required because there is no guarantee that the packet
- * data we get from libpcap/WinPcap is properly aligned.
- *
- * This assumes that, for all compilers that support __attribute__:
- *
- *     1) they support __attribute__((packed));
+ * On Windows, snprintf(), with that name and with C99 behavior - i.e.,
+ * guaranteeing that the formatted string is null-terminated - didn't
+ * appear until Visual Studio 2015.  Prior to that, the C runtime had
+ * only _snprintf(), which *doesn't* guarantee that the string is
+ * null-terminated if it is truncated due to the buffer being too
+ * small.  We therefore can't just define snprintf to be _snprintf
+ * and define vsnprintf to be _vsnprintf, as we're relying on null-
+ * termination of strings in all cases.
  *
- *     2) for all instruction set architectures requiring strict
- *        alignment, declaring a structure with that attribute
- *        causes the compiler to generate code that handles
- *        misaligned 2-byte, 4-byte, and 8-byte integral
- *        quantities.
+ * We also want to allow this to be built with versions of Visual Studio
+ * prior to VS 2015, so we can't rely on snprintf() being present.
  *
- * It does not (yet) handle compilers where you can get the compiler
- * to generate code of that sort by some other means.
- *
- * This is required in order to, for example, keep the compiler from
- * generating, for
- *
- *     if (bp->bp_htype == 1 && bp->bp_hlen == 6 && bp->bp_op == BOOTPREQUEST) {
- *
- * in print-bootp.c, code that loads the first 4-byte word of a
- * "struct bootp", masking out the bp_hops field, and comparing the result
- * against 0x01010600.
- *
- * Note: this also requires that padding be put into the structure,
- * at least for compilers where it's implemented as __attribute__((packed)).
+ * And, if there are any UN*Xes out there on which we can run that
+ * don't have snprintf() or don't have vsnprintf(), we define our
+ * own as well.
  */
-#if !(defined(_MSC_VER) && defined(UNALIGNED))
-/* MSVC may have its own macro defined with the same name and purpose. */
-#undef UNALIGNED
-#define UNALIGNED      __attribute__((packed))
-#endif
+#if !defined(HAVE_SNPRINTF)
+int snprintf (char *str, size_t sz, FORMAT_STRING(const char *format), ...)
+     PRINTFLIKE(3, 4);
+#endif /* !defined(HAVE_SNPRINTF) */
+
+#if !defined(HAVE_VSNPRINTF)
+int vsnprintf (char *str, size_t sz, FORMAT_STRING(const char *format),
+     va_list ap) PRINTFLIKE(3, 0);
+#endif /* !defined(HAVE_VSNPRINTF) */
 
 /*
  * fopen() read and write modes for text files and binary files.
@@ -473,21 +479,17 @@ struct in6_addr {
  */
 
 /*
- * Function attributes, for various compilers.
+ * Statement attributes, for various compilers.
+ *
+ * This was introduced sufficiently recently that compilers implementing
+ * it also implement __has_attribute() (for example, GCC 5.0 and later
+ * have __has_attribute(), and the "fallthrough" attribute was introduced
+ * in GCC 7).
  */
-#include "funcattrs.h"
-
-#ifndef min
-#define min(a,b) ((a)>(b)?(b):(a))
-#endif
-#ifndef max
-#define max(a,b) ((b)>(a)?(b):(a))
-#endif
-
-#ifdef __ATTRIBUTE___FALLTHROUGH_OK
+#if __has_attribute(fallthrough)
 #  define ND_FALL_THROUGH __attribute__ ((fallthrough))
 #else
 #  define ND_FALL_THROUGH
-#endif /* __ATTRIBUTE___FALLTHROUGH_OK */
+#endif /*  __has_attribute(fallthrough) */
 
 #endif /* netdissect_stdinc_h */