1 files changed, 380 insertions, 0 deletions
diff --git a/lib/util/fault.c b/lib/util/fault.c
new file mode 100644
index 00000000000..2ffd5dbd6d1
--- /dev/null
+++ b/lib/util/fault.c
@@ -0,0 +1,380 @@
+/*
+   Unix SMB/CIFS implementation.
+   Critical Fault handling
+   Copyright (C) Andrew Tridgell 1992-1998
+   Copyright (C) Tim Prouty 2009
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+
+#ifdef HAVE_SYS_SYSCTL_H
+#include <sys/sysctl.h>
+#endif
+
+
+#ifdef HAVE_SYS_PRCTL_H
+#include <sys/prctl.h>
+#endif
+
+static char *corepath;
+
+/*******************************************************************
+report a fault
+********************************************************************/
+static void fault_report(int sig)
+{
+	static int counter;
+
+	if (counter) _exit(1);
+
+	counter++;
+
+	DEBUGSEP(0);
+	DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)sys_getpid(),samba_version_string()));
+	DEBUG(0,("\nPlease read the Trouble-Shooting section of the Samba3-HOWTO\n"));
+	DEBUG(0,("\nFrom: http://www.samba.org/samba/docs/Samba3-HOWTO.pdf\n"));
+	DEBUGSEP(0);
+
+	smb_panic("internal error");
+
+	/* smb_panic() never returns, so this is really redundent */
+	exit(1);
+}
+
+/****************************************************************************
+catch serious errors
+****************************************************************************/
+static void sig_fault(int sig)
+{
+	fault_report(sig);
+}
+
+/*******************************************************************
+setup our fault handlers
+********************************************************************/
+void fault_setup(void)
+{
+#ifdef SIGSEGV
+	CatchSignal(SIGSEGV, sig_fault);
+#endif
+#ifdef SIGBUS
+	CatchSignal(SIGBUS, sig_fault);
+#endif
+#ifdef SIGABRT
+	CatchSignal(SIGABRT, sig_fault);
+#endif
+}
+
+/**
+ * Build up the default corepath as "<logbase>/cores/<progname>"
+ */
+static char *get_default_corepath(const char *logbase, const char *progname)
+{
+	char *tmp_corepath;
+
+	/* Setup core dir in logbase. */
+	tmp_corepath = talloc_asprintf(NULL, "%s/cores", logbase);
+	if (!tmp_corepath)
+		return NULL;
+
+	if ((mkdir(tmp_corepath, 0700) == -1) && errno != EEXIST)
+		goto err_out;
+
+	if (chmod(tmp_corepath, 0700) == -1)
+		goto err_out;
+
+	talloc_free(tmp_corepath);
+
+	/* Setup progname-specific core subdir */
+	tmp_corepath = talloc_asprintf(NULL, "%s/cores/%s", logbase, progname);
+	if (!tmp_corepath)
+		return NULL;
+
+	if (mkdir(tmp_corepath, 0700) == -1 && errno != EEXIST)
+		goto err_out;
+
+	if (chown(tmp_corepath, getuid(), getgid()) == -1)
+		goto err_out;
+
+	if (chmod(tmp_corepath, 0700) == -1)
+		goto err_out;
+
+	return tmp_corepath;
+
+ err_out:
+	talloc_free(tmp_corepath);
+	return NULL;
+}
+
+/**
+ * Get the FreeBSD corepath.
+ *
+ * On FreeBSD the current working directory is ignored when creating a core
+ * file.  Instead the core directory is controlled via sysctl.  This consults
+ * the value of "kern.corefile" so the correct corepath can be printed out
+ * before dump_core() calls abort.
+ */
+#if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME))
+static char *get_freebsd_corepath(void)
+{
+	char *tmp_corepath = NULL;
+	char *end = NULL;
+	size_t len = 128;
+	int ret;
+
+	/* Loop with increasing sizes so we don't allocate too much. */
+	do {
+		if (len > 1024)  {
+			goto err_out;
+		}
+
+		tmp_corepath = (char *)talloc_realloc(NULL, tmp_corepath,
+						      char, len);
+		if (!tmp_corepath) {
+			return NULL;
+		}
+
+		ret = sysctlbyname("kern.corefile", tmp_corepath, &len, NULL,
+				   0);
+		if (ret == -1) {
+			if (errno != ENOMEM) {
+				DEBUG(0, ("sysctlbyname failed getting "
+					  "kern.corefile %s\n",
+					  strerror(errno)));
+				goto err_out;
+			}
+
+			/* Not a large enough array, try a bigger one. */
+			len = len << 1;
+		}
+	} while (ret == -1);
+
+	/* Strip off the common filename expansion */
+	if ((end = strrchr_m(tmp_corepath, '/'))) {
+		*end = '\0';
+	}
+
+	return tmp_corepath;
+
+ err_out:
+	if (tmp_corepath) {
+		talloc_free(tmp_corepath);
+	}
+	return NULL;
+}
+#endif
+
+#if defined(HAVE_SYS_KERNEL_PROC_CORE_PATTERN)
+
+/**
+ * Get the Linux corepath.
+ *
+ * On Linux the contents of /proc/sys/kernel/core_pattern indicates the
+ * location of the core path.
+ */
+static char *get_linux_corepath(void)
+{
+	char *end;
+	int fd;
+	char *result;
+
+	fd = open("/proc/sys/kernel/core_pattern", O_RDONLY, 0);
+	if (fd == -1) {
+		return NULL;
+	}
+
+	result = afdgets(fd, NULL, 0);
+	close(fd);
+
+	if (result == NULL) {
+		return NULL;
+	}
+
+	if (result[0] != '/') {
+		/*
+		 * No absolute path, use the default (cwd)
+		 */
+		TALLOC_FREE(result);
+		return NULL;
+	}
+	/* Strip off the common filename expansion */
+
+	end = strrchr_m(result, '/');
+
+	if ((end != result) /* this would be the only / */
+	    && (end != NULL)) {
+		*end = '\0';
+	}
+	return result;
+}
+#endif
+
+
+/**
+ * Try getting system-specific corepath if one exists.
+ *
+ * If the system doesn't define a corepath, then the default is used.
+ */
+static char *get_corepath(const char *logbase, const char *progname)
+{
+#if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME))
+	char *tmp_corepath = NULL;
+	tmp_corepath = get_freebsd_corepath();
+
+	/* If this has been set correctly, we're done. */
+	if (tmp_corepath) {
+		return tmp_corepath;
+	}
+#endif
+
+#if defined(HAVE_SYS_KERNEL_PROC_CORE_PATTERN)
+	char *tmp_corepath = NULL;
+	tmp_corepath = get_linux_corepath();
+
+	/* If this has been set correctly, we're done. */
+	if (tmp_corepath) {
+		return tmp_corepath;
+	}
+#endif
+
+	/* Fall back to the default. */
+	return get_default_corepath(logbase, progname);
+}
+
+/*******************************************************************
+make all the preparations to safely dump a core file
+********************************************************************/
+
+void dump_core_setup(const char *progname)
+{
+	char *logbase = NULL;
+	char *end = NULL;
+
+	if (lp_logfile() && *lp_logfile()) {
+		if (asprintf(&logbase, "%s", lp_logfile()) < 0) {
+			return;
+		}
+		if ((end = strrchr_m(logbase, '/'))) {
+			*end = '\0';
+		}
+	} else {
+		/* We will end up here if the log file is given on the command
+		 * line by the -l option but the "log file" option is not set
+		 * in smb.conf.
+		 */
+		if (asprintf(&logbase, "%s", get_dyn_LOGFILEBASE()) < 0) {
+			return;
+		}
+	}
+
+	SMB_ASSERT(progname != NULL);
+
+	corepath = get_corepath(logbase, progname);
+	if (!corepath) {
+		DEBUG(0, ("Unable to setup corepath for %s: %s\n", progname,
+			  strerror(errno)));
+		goto out;
+	}
+
+
+#ifdef HAVE_GETRLIMIT
+#ifdef RLIMIT_CORE
+	{
+		struct rlimit rlp;
+		getrlimit(RLIMIT_CORE, &rlp);
+		rlp.rlim_cur = MAX(16*1024*1024,rlp.rlim_cur);
+		setrlimit(RLIMIT_CORE, &rlp);
+		getrlimit(RLIMIT_CORE, &rlp);
+		DEBUG(3,("Maximum core file size limits now %d(soft) %d(hard)\n",
+			 (int)rlp.rlim_cur,(int)rlp.rlim_max));
+	}
+#endif
+#endif
+
+	/* FIXME: if we have a core-plus-pid facility, configurably set
+	 * this up here.
+	 */
+ out:
+	SAFE_FREE(logbase);
+}
+
+ void dump_core(void)
+{
+	static bool called;
+
+	if (called) {
+		DEBUG(0, ("dump_core() called recursive\n"));
+		exit(1);
+	}
+	called = true;
+
+	/* Note that even if core dumping has been disabled, we still set up
+	 * the core path. This is to handle the case where core dumping is
+	 * turned on in smb.conf and the relevant daemon is not restarted.
+	 */
+	if (!lp_enable_core_files()) {
+		DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n"));
+		exit(1);
+	}
+
+#if DUMP_CORE
+	/* If we're running as non root we might not be able to dump the core
+	 * file to the corepath.  There must not be an unbecome_root() before
+	 * we call abort(). */
+	if (geteuid() != sec_initial_uid()) {
+		become_root();
+	}
+
+	if (corepath == NULL) {
+		DEBUG(0, ("Can not dump core: corepath not set up\n"));
+		exit(1);
+	}
+
+	if (*corepath != '\0') {
+		/* The chdir might fail if we dump core before we finish
+		 * processing the config file.
+		 */
+		if (chdir(corepath) != 0) {
+			DEBUG(0, ("unable to change to %s\n", corepath));
+			DEBUGADD(0, ("refusing to dump core\n"));
+			exit(1);
+		}
+
+		DEBUG(0,("dumping core in %s\n", corepath));
+	}
+
+	umask(~(0700));
+	dbgflush();
+
+#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
+	/* On Linux we lose the ability to dump core when we change our user
+	 * ID. We know how to dump core safely, so let's make sure we have our
+	 * dumpable flag set.
+	 */
+	prctl(PR_SET_DUMPABLE, 1);
+#endif
+
+	/* Ensure we don't have a signal handler for abort. */
+#ifdef SIGABRT
+	CatchSignal(SIGABRT, SIG_DFL);
+#endif
+
+	abort();
+
+#else /* DUMP_CORE */
+	exit(1);
+#endif /* DUMP_CORE */
+}