]> The Tcpdump Group git mirrors - libpcap/blobdiff - fmtutils.c
Add support for UTF-8 strings on Windows.
[libpcap] / fmtutils.c
index a4f59c2b2529840fa7d3b9793803691c661f6509..8f6921fbc0467ce7dfdb5c7c116e3f0c6a2037c9 100644 (file)
 #include <string.h>
 #include <errno.h>
 
-#include <pcap/pcap.h>
+#include "pcap-int.h"
 
 #include "portability.h"
 
 #include "fmtutils.h"
 
+#ifdef _WIN32
+#include "charconv.h"
+#endif
+
+/*
+ * Set the encoding.
+ */
+#ifdef _WIN32
+/*
+ * True if we shouold use UTF-8.
+ */
+static int use_utf_8;
+
+void
+pcap_fmt_set_encoding(unsigned int opts)
+{
+       if (opts == PCAP_CHAR_ENC_UTF_8)
+               use_utf_8 = 1;
+}
+#else
+void
+pcap_fmt_set_encoding(unsigned int opts _U_)
+{
+       /*
+        * Nothing to do here.
+        */
+}
+#endif
+
+#ifdef _WIN32
+/*
+ * Convert a null-terminated UTF-16LE string to UTF-8, putting it into
+ * a buffer starting at the specified location and stopping if we go
+ * past the specified size.  This will only put out complete UTF-8
+ * sequences.
+ *
+ * We do this ourselves because Microsoft doesn't offer a "convert and
+ * stop at a UTF-8 character boundary if we run out of space" routine.
+ */
+#define IS_LEADING_SURROGATE(c) \
+       ((c) >= 0xd800 && (c) < 0xdc00)
+#define IS_TRAILING_SURROGATE(c) \
+       ((c) >= 0xdc00 && (c) < 0xe000)
+#define SURROGATE_VALUE(leading, trailing) \
+       (((((leading) - 0xd800) << 10) | ((trailing) - 0xdc00)) + 0x10000)
+#define REPLACEMENT_CHARACTER  0x0FFFD
+
+static char *
+utf_16le_to_utf_8_truncated(wchar_t *utf_16, char *utf_8, size_t utf_8_len)
+{
+       wchar_t c, c2;
+       uint32_t uc;
+
+       if (utf_8_len == 0) {
+               /*
+                * Not even enough room for a trailing '\0'.
+                * Don't put anything into the buffer.
+                */
+               return (utf_8);
+       }
+
+       while ((c = *utf_16++) != '\0') {
+               if (IS_LEADING_SURROGATE(c)) {
+                       /*
+                        * Leading surrogate.  Must be followed by
+                        * a trailing surrogate.
+                        */
+                       c2 = *utf_16;
+                       if (c2 == '\0') {
+                               /*
+                                * Oops, string ends with a lead
+                                * surrogate.  Try to drop in
+                                * a REPLACEMENT CHARACTER, and
+                                * don't move the string pointer,
+                                * so on the next trip through
+                                * the loop we grab the terminating
+                                * '\0' and quit.
+                                */
+                               uc = REPLACEMENT_CHARACTER;
+                       } else {
+                               /*
+                                * OK, we can consume this 2-octet
+                                * value.
+                                */
+                               utf_16++;
+                               if (IS_TRAILING_SURROGATE(c2)) {
+                                       /*
+                                        * Trailing surrogate.
+                                        * This calculation will,
+                                        * for c being a leading
+                                        * surrogate and c2 being
+                                        * a trailing surrogate,
+                                        * produce a value between
+                                        * 0x100000 and 0x10ffff,
+                                        * so it's always going to be
+                                        * a valid Unicode code point.
+                                        */
+                                       uc = SURROGATE_VALUE(c, c2);
+                               } else {
+                                       /*
+                                        * Not a trailing surroage;
+                                        * try to drop in a
+                                        * REPLACEMENT CHARACTER.
+                                        */
+                                       uc = REPLACEMENT_CHARACTER;
+                               }
+                       }
+               } else {
+                       /*
+                        * Not a leading surrogate.
+                        */
+                       if (IS_TRAILING_SURROGATE(c)) {
+                               /*
+                                * Trailing surrogate without
+                                * a preceding leading surrogate.
+                                * Try to drop in a REPLACEMENT
+                                * CHARACTER.
+                                */
+                               uc = REPLACEMENT_CHARACTER;
+                       } else {
+                               /*
+                                * This is a valid BMP character;
+                                * drop it in.
+                                */
+                               uc = c;
+                       }
+               }
+
+               /*
+                * OK, uc is a valid Unicode character; how
+                * many bytes worth of UTF-8 does it require?
+                */
+               if (uc < 0x0080) {
+                       /* 1 byte. */
+                       if (utf_8_len < 2) {
+                               /*
+                                * Not enough room for that byte
+                                * plus a trailing '\0'.
+                                */
+                               break;
+                       }
+                       *utf_8++ = (char)uc;
+                       utf_8_len--;
+               } else if (uc < 0x0800) {
+                       /* 2 bytes. */
+                       if (utf_8_len < 3) {
+                               /*
+                                * Not enough room for those bytes
+                                * plus a trailing '\0'.
+                                */
+                               break;
+                       }
+                       *utf_8++ = ((uc >> 6) & 0x3F) | 0xC0;
+                       *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;
+                       utf_8_len -= 2;
+               } else if (uc < 0x010000) {
+                       /* 3 bytes. */
+                       if (utf_8_len < 4) {
+                               /*
+                                * Not enough room for those bytes
+                                * plus a trailing '\0'.
+                                */
+                               break;
+                       }
+                       *utf_8++ = ((uc >> 12) & 0x0F) | 0xE0;
+                       *utf_8++ = ((uc >> 6) & 0x3F) | 0x80;
+                       *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;
+                       utf_8_len -= 3;
+               } else {
+                       /* 4 bytes. */
+                       if (utf_8_len < 5) {
+                               /*
+                                * Not enough room for those bytes
+                                * plus a trailing '\0'.
+                                */
+                               break;
+                       }
+                       *utf_8++ = ((uc >> 18) & 0x03) | 0xF0;
+                       *utf_8++ = ((uc >> 12) & 0x3F) | 0x80;
+                       *utf_8++ = ((uc >> 6) & 0x3F) | 0x80;
+                       *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;
+                       utf_8_len -= 3;
+               }
+       }
+
+       /*
+        * OK, we have enough room for (at least) a trailing '\0'.
+        * (We started out with enough room, thanks to the test
+        * for a zero-length buffer at the beginning, and if
+        * there wasn't enough room for any character we wanted
+        * to put into the the buffer *plus* a trailing '\0',
+        * we'd have quit before putting it into the buffer,
+        * and thus would have left enough room for the trailing
+        * '\0'.)
+        *
+        * Drop it in.
+        */
+       *utf_8 = '\0';
+
+       /*
+        * Return a pointer to the terminating '\0', in case we
+        * want to drop something in after that.
+        */
+       return (utf_8);
+}
+#endif /* _WIN32 */
+
 /*
  * Generate an error message based on a format, arguments, and an
  * errno, with a message for the errno after the formatted output.
@@ -89,18 +296,35 @@ pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,
        /*
         * Now append the string for the error code.
         */
-#if defined(HAVE_STRERROR_S)
+#if defined(HAVE__WCSERROR_S)
        /*
-        * We have a Windows-style strerror_s().
+        * We have a Windows-style _wcserror_s().
+        * Generate a UTF-16LE error message.
         */
-       errno_t err = strerror_s(p, errbuflen_remaining, errnum);
+       wchar_t utf_16_errbuf[PCAP_ERRBUF_SIZE];
+       errno_t err = _wcserror_s(utf_16_errbuf, sizeof (utf_16_errbuf), errnum);
        if (err != 0) {
                /*
                 * It doesn't appear to be documented anywhere obvious
-                * what the error returns from strerror_s().
+                * what the error returns from _wcserror_s().
                 */
                snprintf(p, errbuflen_remaining, "Error %d", errnum);
+               return;
        }
+
+       /*
+        * Now convert it from UTF-16LE to UTF-8, dropping it in the
+        * remaining space in the buffer, and truncating it - cleanly,
+        * on a UTF-8 character boundary - if it doesn't fit.
+        */
+       utf_16le_to_utf_8_truncated(utf_16_errbuf, p, errbuflen_remaining);
+
+       /*
+        * Now, if we're not in UTF-8 mode, convert errbuf to the
+        * local code page.
+        */
+       if (!use_utf_8)
+               utf_8_to_acp_truncated(errbuf);
 #elif defined(HAVE_GNU_STRERROR_R)
        /*
         * We have a GNU-style strerror_r(), which is *not* guaranteed to
@@ -136,7 +360,7 @@ pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,
        }
 #else
        /*
-        * We have neither strerror_s() nor strerror_r(), so we're
+        * We have neither _wcserror_s() nor strerror_r(), so we're
         * stuck with using pcap_strerror().
         */
        snprintf(p, errbuflen_remaining, "%s", pcap_strerror(errnum));
@@ -157,7 +381,8 @@ pcap_fmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,
        char *p;
        size_t errbuflen_remaining;
        DWORD retval;
-       char win32_errbuf[PCAP_ERRBUF_SIZE+1];
+       wchar_t utf_16_errbuf[PCAP_ERRBUF_SIZE];
+       size_t utf_8_len;
 
        va_start(ap, fmt);
        vsnprintf(errbuf, errbuflen, fmt, ap);
@@ -196,9 +421,9 @@ pcap_fmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,
         * get the message translated if it's in a language they don't
         * happen to understand.
         */
-       retval = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS|FORMAT_MESSAGE_MAX_WIDTH_MASK,
+       retval = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS|FORMAT_MESSAGE_MAX_WIDTH_MASK,
            NULL, errnum, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-           win32_errbuf, PCAP_ERRBUF_SIZE, NULL);
+           utf_16_errbuf, PCAP_ERRBUF_SIZE, NULL);
        if (retval == 0) {
                /*
                 * Failed.
@@ -208,6 +433,27 @@ pcap_fmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,
                return;
        }
 
-       snprintf(p, errbuflen_remaining, "%s (%lu)", win32_errbuf, errnum);
+       /*
+        * Now convert it from UTF-16LE to UTF-8.
+        */
+       p = utf_16le_to_utf_8_truncated(utf_16_errbuf, p, errbuflen_remaining);
+
+       /*
+        * Now append the error number, if it fits.
+        */
+       utf_8_len = p - errbuf;
+       errbuflen_remaining -= utf_8_len;
+       if (utf_8_len == 0) {
+               /* The message was empty. */
+               snprintf(p, errbuflen_remaining, "(%lu)", errnum);
+       } else
+               snprintf(p, errbuflen_remaining, " (%lu)", errnum);
+
+       /*
+        * Now, if we're not in UTF-8 mode, convert errbuf to the
+        * local code page.
+        */
+       if (!use_utf_8)
+               utf_8_to_acp_truncated(errbuf);
 }
 #endif