From fed69cc7ac1bccb7012a68d954b58c6de9ad75e7 Mon Sep 17 00:00:00 2001

From: Tomas Heinrich <theinric@redhat.com>

Date: Sun, 10 Jul 2016 23:46:42 +0200

Subject: [PATCH] Make state file handling in imjournal more robust

---

 plugins/imjournal/imjournal.c | 98 ++++++++++++++++++++++++++++++-------------

 1 file changed, 70 insertions(+), 28 deletions(-)

diff --git a/plugins/imjournal/imjournal.c b/plugins/imjournal/imjournal.c

index f97b745..1ebbd1c 100755

--- a/plugins/imjournal/imjournal.c

+++ b/plugins/imjournal/imjournal.c

@@ -70,6 +70,7 @@ static struct configSettings_s {

 	int ratelimitInterval;

 	int ratelimitBurst;

 	int bIgnorePrevious;

+	int bIgnoreNonValidStatefile;

 	int iDfltSeverity;

 	int iDfltFacility;

 	char *dfltTag;

@@ -84,6 +85,7 @@ static struct cnfparamdescr modpdescr[] = {

 	{ "ratelimit.burst", eCmdHdlrInt, 0 },

 	{ "persiststateinterval", eCmdHdlrInt, 0 },

 	{ "ignorepreviousmessages", eCmdHdlrBinary, 0 },

+	{ "ignorenonvalidstatefile", eCmdHdlrBinary, 0 },

 	{ "defaultseverity", eCmdHdlrSeverity, 0 },

 	{ "defaultfacility", eCmdHdlrString, 0 },

 	{ "defaulttag", eCmdHdlrGetWord, 0 },

@@ -441,23 +443,36 @@ static rsRetVal

 persistJournalState () {

 	DEFiRet;

 	FILE *sf; /* state file */

+	char tmp_sf[MAXFNAME];

 	char *cursor;

 	int ret = 0;

 	/* On success, sd_journal_get_cursor()  returns 1 in systemd

 	   197 or older and 0 in systemd 198 or newer */

 	if ((ret = sd_journal_get_cursor(j, &cursor)) >= 0) {

-		if ((sf = fopen(cs.stateFile, "wb")) != NULL) {

+		/* we create a temporary name by adding a ".tmp"

+		 * suffix to the end of our state file's name

+		 */

+		snprintf(tmp_sf, sizeof(tmp_sf), "%s.tmp", cs.stateFile);

+		if ((sf = fopen(tmp_sf, "wb")) != NULL) {

 			if (fprintf(sf, "%s", cursor) < 0) {

 				iRet = RS_RET_IO_ERROR;

 			}

 			fclose(sf);

 			free(cursor);

+			/* change the name of the file to the configured one */

+			if (iRet == RS_RET_OK && rename(tmp_sf, cs.stateFile) == -1) {

+				char errStr[256];

+				rs_strerror_r(errno, errStr, sizeof(errStr));

+				iRet = RS_RET_IO_ERROR;

+				errmsg.LogError(0, iRet, "rename() failed: "

+					"'%s', new path: '%s'\n", errStr, cs.stateFile);

+			}

 		} else {

 			char errStr[256];

 			rs_strerror_r(errno, errStr, sizeof(errStr));

 			errmsg.LogError(0, RS_RET_FOPEN_FAILURE, "fopen() failed: "

-				"'%s', path: '%s'\n", errStr, cs.stateFile);

+				"'%s', path: '%s'\n", errStr, tmp_sf);

 			iRet = RS_RET_FOPEN_FAILURE;

 		}

 	} else {

@@ -515,6 +530,35 @@ finalize_it:

 	RETiRet;

 }

+/* Seek to the very end of the journal and ignore all older

+ * messages.

+ */

+static rsRetVal

+skipOldMessages(void)

+{

+	DEFiRet;

+

+	if (sd_journal_seek_tail(j) < 0) {

+		char errStr[256];

+

+		rs_strerror_r(errno, errStr, sizeof(errStr));

+		errmsg.LogError(0, RS_RET_ERR,

+			"sd_journal_seek_tail() failed: '%s'", errStr);

+		ABORT_FINALIZE(RS_RET_ERR);

+        }

+	if (sd_journal_previous(j) < 0) {

+		char errStr[256];

+

+		rs_strerror_r(errno, errStr, sizeof(errStr));

+		errmsg.LogError(0, RS_RET_ERR,

+			"sd_journal_previous() failed: '%s'", errStr);

+		ABORT_FINALIZE(RS_RET_ERR);

+	}

+

+finalize_it:

+	RETiRet;

+

+}

 /* This function loads a journal cursor from the state file.

  */

@@ -546,41 +590,32 @@ loadJournalState()

 					errmsg.LogError(0, RS_RET_ERR, "imjournal: "

 						"couldn't seek to cursor `%s'\n", readCursor);

 					iRet = RS_RET_ERR;

-					goto finalize_it;

+				} else {

+					sd_journal_next(j);

 				}

-				sd_journal_next(j);

 			} else {

 				errmsg.LogError(0, RS_RET_IO_ERROR, "imjournal: "

 					"fscanf on state file `%s' failed\n", cs.stateFile);

 				iRet = RS_RET_IO_ERROR;

-				goto finalize_it;

 			}

+

 			fclose(r_sf);

+

+			if (iRet != RS_RET_OK && cs.bIgnoreNonValidStatefile) {

+				/* ignore state file errors */

+				iRet = RS_RET_OK;

+				errmsg.LogError(0, NO_ERRCODE,

+					"imjournal: ignoring invalid state file");

+				if (cs.bIgnorePrevious) {

+					skipOldMessages();

+				}

+			}

 		} else {

 			errmsg.LogError(0, RS_RET_FOPEN_FAILURE, "imjournal: "

 					"open on state file `%s' failed\n", cs.stateFile);

 		}

-	} else {

-		/* when IgnorePrevious, seek to the end of journal */

-		if (cs.bIgnorePrevious) {

-			if (sd_journal_seek_tail(j) < 0) {

-				char errStr[256];

-

-				rs_strerror_r(errno, errStr, sizeof(errStr));

-				errmsg.LogError(0, RS_RET_ERR,

-					"sd_journal_seek_tail() failed: '%s'", errStr);

-				ABORT_FINALIZE(RS_RET_ERR);

-			}

-

-			if (sd_journal_previous(j) < 0) {

-				char errStr[256];

-

-				rs_strerror_r(errno, errStr, sizeof(errStr));

-				errmsg.LogError(0, RS_RET_ERR,

-					"sd_journal_previous() failed: '%s'", errStr);

-				ABORT_FINALIZE(RS_RET_ERR);

-			}

-		}

+	} else if (cs.bIgnorePrevious) {

+		skipOldMessages();

 	} 

 finalize_it:

@@ -598,6 +633,8 @@ CODESTARTrunInput

 	if (cs.stateFile) {

 		CHKiRet(loadJournalState());

+	} else if (cs.bIgnorePrevious) {

+		skipOldMessages();

 	}

 	/* this is an endless loop - it is terminated when the thread is

@@ -641,6 +678,7 @@ BEGINbeginCnfLoad

 CODESTARTbeginCnfLoad

 	bLegacyCnfModGlobalsPermitted = 1;

+	cs.bIgnoreNonValidStatefile = 1;

 	cs.iPersistStateInterval = DFLT_persiststateinterval;

 	cs.stateFile = NULL;

 	cs.ratelimitBurst = 20000;

@@ -739,7 +777,9 @@ CODESTARTsetModCnf

 		} else if(!strcmp(modpblk.descr[i].name, "ratelimit.interval")) {

 			cs.ratelimitInterval = (int) pvals[i].val.d.n;

 		} else if (!strcmp(modpblk.descr[i].name, "ignorepreviousmessages")) {

-			cs.bIgnorePrevious = (int) pvals[i].val.d.n; 

+			cs.bIgnorePrevious = (int) pvals[i].val.d.n;

+		} else if (!strcmp(modpblk.descr[i].name, "ignorenonvalidstatefile")) {

+			cs.bIgnoreNonValidStatefile = (int) pvals[i].val.d.n;

 		} else if (!strcmp(modpblk.descr[i].name, "defaultseverity")) {

 			cs.iDfltSeverity = (int) pvals[i].val.d.n;

 		} else if (!strcmp(modpblk.descr[i].name, "defaultfacility")) {

@@ -806,7 +846,9 @@ CODEmodInit_QueryRegCFSLineHdlr

 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"imjournalstatefile", 0, eCmdHdlrGetWord,

 		NULL, &cs.stateFile, STD_LOADABLE_MODULE_ID));

 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"imjournalignorepreviousmessages", 0, eCmdHdlrBinary,

-		NULL, &cs.bIgnorePrevious, STD_LOADABLE_MODULE_ID)); 

+		NULL, &cs.bIgnorePrevious, STD_LOADABLE_MODULE_ID));

+	CHKiRet(omsdRegCFSLineHdlr((uchar *)"imjournalignorenonvalidstatefile", 0, eCmdHdlrBinary,

+		NULL, &cs.bIgnoreNonValidStatefile, STD_LOADABLE_MODULE_ID));

 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"imjournaldefaultseverity", 0, eCmdHdlrSeverity,

 		NULL, &cs.iDfltSeverity, STD_LOADABLE_MODULE_ID));

 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"imjournaldefaultfacility", 0, eCmdHdlrCustomHandler,

-- 

2.5.5