pass old pattern to ccpp hook and use it

abrtd:
instead of
"|/usr/libexec/abrt-ccpp-hook DEBUG_DUMPS_DIR %p %s %u %c",
sets coredump handler to
"|/usr/libexec/abrt-ccpp-hook DEBUG_DUMPS_DIR %s %c %p %u %g %t %h %e OLD_PATTERN"

abrt-ccpp-hook:
expands OLD_PATTERN using values of %s %c %p %u %g %t %h %e
and uses it as a name of "compat coredump".

Patch has a feature which prevents usage of kernel-truncated
OLD_PATTERN: it is passed as hex string *with terminating NUL*
(encoded as 00). If ccpp hook doesn't see 00, it refuses to use
OLD_PATTERN and uses string "core" instead.

Run tested. On a new kernel, passes up to 27 char long old pattern.
Longer patterns are still truncated.
This may be improved in future kernels.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

3 files changed, 120 insertions, 12 deletions

diff --git a/lib/Plugins/CCpp.cpp b/lib/Plugins/CCpp.cpp
index 3dbd73e1..b028c416 100644
--- a/lib/Plugins/CCpp.cpp
+++ b/lib/Plugins/CCpp.cpp
@@ -39,15 +39,27 @@
 using namespace std;
 
 #define CORE_PATTERN_IFACE      "/proc/sys/kernel/core_pattern"
-#define CORE_PATTERN            "|"CCPP_HOOK_PATH" "DEBUG_DUMPS_DIR" %p %s %u %c"
+/*
+ * %s - signal number
+ * %c - ulimit -c value
+ * %p - pid
+ * %u - uid
+ * %g - gid
+ * %t - UNIX time of dump
+ * %h - hostname
+ * %e - executable filename
+ * %% - output one "%"
+ */
+#define CORE_PATTERN            "|"CCPP_HOOK_PATH" "DEBUG_DUMPS_DIR" %s %c %p %u %g %t %h %e"
+
 #define CORE_PIPE_LIMIT_IFACE   "/proc/sys/kernel/core_pipe_limit"
 /* core_pipe_limit specifies how many dump_helpers might run at the same time
-0 - means unlimited, but the it's not guaranteed that /proc/<pid> of crashing
-process might not be available for dump_helper
-4 - means that 4 dump_helpers can run at the same time, which should be enough
-for ABRT, we can miss some crashes, but what are the odds that more processes
-crash at the same time? This value has been recommended by nhorman
-*/
+ * 0 - means unlimited, but the it's not guaranteed that /proc/<pid>
+ *     of crashing process will be available for dump_helper
+ * 4 - means that 4 dump_helpers can run at the same time, which should be enough
+ *     for ABRT, we can miss some crashes, but what are the odds that more processes
+ *     crash at the same time? This value has been recommended by nhorman
+ */
 #define CORE_PIPE_LIMIT "4"
 
 #define DEBUGINFO_CACHE_DIR     LOCALSTATEDIR"/cache/abrt-di"
@@ -796,7 +808,7 @@ void CAnalyzerCCpp::Init()
     }
     if (m_sOldCorePattern[0] == '|')
     {
-        if (m_sOldCorePattern == CORE_PATTERN)
+        if (strncmp(m_sOldCorePattern.c_str(), CORE_PATTERN, strlen(CORE_PATTERN)) == 0)
         {
             log("warning: %s already contains %s, "
                 "did abrt daemon crash recently?",
@@ -820,14 +832,35 @@ void CAnalyzerCCpp::Init()
     fp = fopen(CORE_PATTERN_IFACE, "w");
     if (fp)
     {
-        fputs(CORE_PATTERN, fp);
+        if (m_sOldCorePattern[0] != '|')
+        {
+            const char *old = m_sOldCorePattern.c_str();
+            unsigned len = strchrnul(old, '\n') - old;
+            char *hex_old = (char*)xmalloc(len * 2 + 1);
+            bin2hex(hex_old, old, len)[0] = '\0';
+            /* Trailing 00 is a sentinel. Decoder in the hook will check it.
+             * If it won't see it, then kernel has truncated the argument:
+             */
+            char *pattern = xasprintf("%s %s00", CORE_PATTERN, hex_old);
+            //log("old:'%s'->'%s'", old, hex_old);
+            //log("pattern:'%s'", pattern);
+
+            fputs(pattern, fp);
+
+            free(pattern);
+            free(hex_old);
+        }
+        else
+        {
+            fputs(CORE_PATTERN, fp);
+        }
         fclose(fp);
     }
 
     /* read the core_pipe_limit and change it if it's == 0
-       otherwise the abrt-hook-ccpp won't be able to read /proc/<pid>
-       of the crashing process
-    */
+     * otherwise the abrt-hook-ccpp won't be able to read /proc/<pid>
+     * of the crashing process
+     */
     fp = fopen(CORE_PIPE_LIMIT_IFACE, "r");
     if (fp)
     {
diff --git a/lib/Utils/Makefile.am b/lib/Utils/Makefile.am
index b22e1177..12829b90 100644
--- a/lib/Utils/Makefile.am
+++ b/lib/Utils/Makefile.am
@@ -12,6 +12,7 @@ AM_YFLAGS = --verbose
 libABRTUtils_la_SOURCES = \
     xfuncs.cpp \
     encbase64.cpp \
+    binhex.cpp \
     stdio_helpers.cpp \
     read_write.cpp \
     logging.cpp \
diff --git a/lib/Utils/binhex.cpp b/lib/Utils/binhex.cpp
new file mode 100644
index 00000000..1fcb7445
--- /dev/null
+++ b/lib/Utils/binhex.cpp
@@ -0,0 +1,74 @@
+/*
+    Copyright (C) 2010  ABRT team
+    Copyright (C) 2010  RedHat Inc
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License version 2
+    as published by the Free Software Foundation.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+#include "abrtlib.h"
+
+static const char hexdigits_locase[] = "0123456789abcdef";
+
+/* Emit a string of hex representation of bytes */
+char *bin2hex(char *dst, const char *str, int count)
+{
+	while (count) {
+		unsigned char c = *str++;
+		/* put lowercase hex digits */
+		*dst++ = hexdigits_locase[c >> 4];
+		*dst++ = hexdigits_locase[c & 0xf];
+		count--;
+	}
+	return dst;
+}
+
+/* Convert "xxxxxxxx" hex string to binary, no more than COUNT bytes */
+char *hex2bin(char *dst, const char *str, int count)
+{
+	/* Parts commented out with // allow parsing
+	 * of strings like "xx:x:x:xx:xx:xx:xxxxxx"
+	 * (IPv6, ethernet addresses and the like).
+	 */
+	errno = EINVAL;
+	while (*str && count) {
+		uint8_t val;
+		uint8_t c;
+
+		c = *str++;
+		if (isdigit(c))
+			val = c - '0';
+		else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
+			val = (c|0x20) - ('a' - 10);
+		else
+			return NULL;
+		val <<= 4;
+		c = *str;
+		if (isdigit(c))
+			val |= c - '0';
+		else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
+			val |= (c|0x20) - ('a' - 10);
+		//else if (c == ':' || c == '\0')
+		//	val >>= 4;
+		else
+			return NULL;
+
+		*dst++ = val;
+		//if (c != '\0')
+			str++;
+		//if (*str == ':')
+		//	str++;
+		count--;
+	}
+	errno = (*str ? ERANGE : 0);
+	return dst;
+}