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0baae61e42
Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Martin Schwenke <mschwenke@ddn.com>
345 lines
7.9 KiB
C
345 lines
7.9 KiB
C
/*
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Unix SMB/CIFS implementation.
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Samba utility functions
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Copyright (C) Andrew Tridgell 1992-2011
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based on old fault.c code, which had:
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Copyright (C) Jeremy Allison 2001-2007
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Copyright (C) Simo Sorce 2001
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Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
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Copyright (C) James Peach 2006
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "lib/util/util_file.h"
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#include "system/filesys.h"
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#ifdef HAVE_SYS_SYSCTL_H
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#include <sys/sysctl.h>
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#endif
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#ifdef HAVE_SYS_PRCTL_H
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#include <sys/prctl.h>
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#endif
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static char *corepath;
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static bool using_helper_binary = false;
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/**
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* Build up the default corepath as "<logbase>/cores/<progname>"
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*/
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static char *get_default_corepath(const char *logbase, const char *progname)
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{
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const mode_t mode = 0700;
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const uid_t uid = getuid();
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char *tmp_corepath;
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/* Setup core dir in logbase. */
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tmp_corepath = talloc_asprintf(NULL, "%s/cores", logbase);
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if (!tmp_corepath) {
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DEBUG(0, ("Out of memory\n"));
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return NULL;
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}
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if (!directory_create_or_exist_strict(tmp_corepath, uid, mode)) {
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DEBUG(0, ("Failed to create %s for user %d with mode 0%o\n",
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tmp_corepath, (int)uid, (int)mode));
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goto err_out;
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}
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/* Setup progname-specific core subdir */
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tmp_corepath = talloc_asprintf_append(tmp_corepath, "/%s", progname);
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if (!tmp_corepath) {
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DEBUG(0, ("Out of memory\n"));
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goto err_out;
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}
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if (!directory_create_or_exist(tmp_corepath, mode)) {
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DEBUG(0, ("Failed to create %s for user %d with mode 0%o\n",
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tmp_corepath, (int)uid, (int)mode));
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goto err_out;
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}
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return tmp_corepath;
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err_out:
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talloc_free(tmp_corepath);
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return NULL;
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}
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/**
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* Get the FreeBSD corepath.
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*
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* On FreeBSD the current working directory is ignored when creating a core
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* file. Instead the core directory is controlled via sysctl. This consults
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* the value of "kern.corefile" so the correct corepath can be printed out
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* before dump_core() calls abort.
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*/
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#if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME))
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static char *get_freebsd_corepath(void)
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{
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char *tmp_corepath = NULL;
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char *end = NULL;
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size_t len = 128;
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int ret;
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/* Loop with increasing sizes so we don't allocate too much. */
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do {
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if (len > 1024) {
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goto err_out;
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}
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tmp_corepath = (char *)talloc_realloc(NULL, tmp_corepath,
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char, len);
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if (!tmp_corepath) {
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return NULL;
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}
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ret = sysctlbyname("kern.corefile", tmp_corepath, &len, NULL,
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0);
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if (ret == -1) {
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if (errno != ENOMEM) {
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DEBUG(0, ("sysctlbyname failed getting "
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"kern.corefile %s\n",
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strerror(errno)));
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goto err_out;
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}
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/* Not a large enough array, try a bigger one. */
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len = len << 1;
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}
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} while (ret == -1);
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/* Strip off the common filename expansion */
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if ((end = strrchr_m(tmp_corepath, '/'))) {
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*end = '\0';
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}
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return tmp_corepath;
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err_out:
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if (tmp_corepath) {
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talloc_free(tmp_corepath);
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}
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return NULL;
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}
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#endif
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#if defined(HAVE_SYS_KERNEL_PROC_CORE_PATTERN)
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/**
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* Get the Linux corepath.
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*
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* On Linux the contents of /proc/sys/kernel/core_pattern indicates the
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* location of the core path.
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*/
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static char *get_linux_corepath(void)
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{
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char *end;
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int fd;
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char *result;
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fd = open("/proc/sys/kernel/core_pattern", O_RDONLY, 0);
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if (fd == -1) {
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return NULL;
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}
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result = afdgets(fd, NULL, 0);
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close(fd);
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if (result == NULL) {
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return NULL;
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}
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if (result[0] != '/') {
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/*
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* No absolute path, use the default (cwd)
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*/
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if (result[0] == '|') {
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/*
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* Core dump handled by helper binaries
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*/
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using_helper_binary = true;
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}
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TALLOC_FREE(result);
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return NULL;
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}
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/* Strip off the common filename expansion */
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end = strrchr_m(result, '/');
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if ((end != result) /* this would be the only / */
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&& (end != NULL)) {
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*end = '\0';
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}
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return result;
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}
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#endif
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/**
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* Try getting system-specific corepath if one exists.
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*
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* If the system doesn't define a corepath, then the default is used.
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*/
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static char *get_corepath(const char *logbase, const char *progname)
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{
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#if (defined(FREEBSD) && defined(HAVE_SYSCTLBYNAME))
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char *tmp_corepath = NULL;
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tmp_corepath = get_freebsd_corepath();
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/* If this has been set correctly, we're done. */
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if (tmp_corepath) {
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return tmp_corepath;
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}
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#endif
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#if defined(HAVE_SYS_KERNEL_PROC_CORE_PATTERN)
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char *tmp_corepath = NULL;
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tmp_corepath = get_linux_corepath();
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/* If this has been set correctly, we're done. */
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if (tmp_corepath) {
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return tmp_corepath;
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}
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#endif
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/* Fall back to the default. */
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return get_default_corepath(logbase, progname);
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}
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/*******************************************************************
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make all the preparations to safely dump a core file
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********************************************************************/
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void dump_core_setup(const char *progname, const char *log_file)
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{
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char *logbase = NULL;
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char *end = NULL;
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if (log_file && *log_file) {
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if (asprintf(&logbase, "%s", log_file) < 0) {
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return;
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}
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if ((end = strrchr_m(logbase, '/'))) {
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*end = '\0';
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}
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} else {
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/* We will end up here if the log file is given on the command
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* line by the -l option but the "log file" option is not set
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* in smb.conf.
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*/
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if (asprintf(&logbase, "%s", get_dyn_LOGFILEBASE()) < 0) {
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return;
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}
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}
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SMB_ASSERT(progname != NULL);
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corepath = get_corepath(logbase, progname);
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if (!corepath) {
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DEBUG(0, ("Unable to setup corepath for %s: %s\n", progname,
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strerror(errno)));
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goto out;
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}
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/* FIXME: if we have a core-plus-pid facility, configurably set
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* this up here.
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*/
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out:
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SAFE_FREE(logbase);
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}
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void dump_core(void)
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{
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static bool called;
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if (called) {
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DEBUG(0, ("dump_core() called recursive\n"));
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exit(1);
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}
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called = true;
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/* Note that even if core dumping has been disabled, we still set up
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* the core path. This is to handle the case where core dumping is
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* turned on in smb.conf and the relevant daemon is not restarted.
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*/
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if (!lp_enable_core_files()) {
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DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n"));
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exit(1);
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}
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#if DUMP_CORE
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/* If we're running as non root we might not be able to dump the core
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* file to the corepath. There must not be an unbecome_root() before
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* we call abort(). */
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if (geteuid() != sec_initial_uid()) {
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become_root();
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}
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if (corepath == NULL) {
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DEBUG(0, ("Can not dump core: corepath not set up\n"));
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exit(1);
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}
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if (*corepath != '\0') {
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/*
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* Check whether coredump is handled by helper binaries or not.
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* If so skip chdir().
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*/
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if (!using_helper_binary) {
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/* The chdir might fail if we dump core before we finish
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* processing the config file.
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*/
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if (chdir(corepath) != 0) {
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DEBUG(0, ("unable to change to %s\n", corepath));
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DEBUGADD(0, ("refusing to dump core\n"));
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exit(1);
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}
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DEBUG(0,("dumping core in %s\n", corepath));
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} else {
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DEBUG(0,("coredump is handled by helper binary "
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"specified at /proc/sys/kernel/core_pattern\n"));
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}
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}
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umask(~(0700));
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dbgflush();
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#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
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/* On Linux we lose the ability to dump core when we change our user
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* ID. We know how to dump core safely, so let's make sure we have our
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* dumpable flag set.
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*/
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prctl(PR_SET_DUMPABLE, 1);
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#endif
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/* Ensure we don't have a signal handler for abort. */
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#ifdef SIGABRT
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CatchSignal(SIGABRT, SIG_DFL);
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#endif
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abort();
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#else /* DUMP_CORE */
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exit(1);
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#endif /* DUMP_CORE */
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}
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