[nagiosplug] Don't prepend "^Inst" or append a space to the ...

[Nagios Plugin Development]

 Module: nagiosplug
 Branch: master
 Commit: 7918f5868c08909050aa083eeb819d110f2d160d
 Author: Alex Bradley <a.bradley at alumni.cs.ubc.ca>
   Date: Tue Oct  2 23:22:54 2012 -0700
    URL: http://nagiosplug.git.sf.net/git/gitweb.cgi?p=nagiosplug/nagiosplug;a=commit;h=7918f58

Don't prepend "^Inst" or append a space to the "include", "exclude", or
"critical" regular expressions. Instead, check for lines beginning
with "Inst" using strncmp and apply the regular expressions only when
such lines are found.

Fixes Debian bug #522812, along the lines suggested by the bug
submitter, Justin T Pryzby.

---

 plugins/check_apt.c |   35 ++++++++++++++++++-----------------
 1 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/plugins/check_apt.c b/plugins/check_apt.c
index 7efa596..26499ae 100644
--- a/plugins/check_apt.c
+++ b/plugins/check_apt.c
@@ -49,6 +49,8 @@ typedef enum { UPGRADE, DIST_UPGRADE, NO_UPGRADE } upgrade_type;
 #ifndef PATH_TO_APTGET
 # define PATH_TO_APTGET "/usr/bin/apt-get"
 #endif /* PATH_TO_APTGET */
+/* String found at the beginning of the apt output lines we're interested in */
+#define PKGINST_PREFIX "Inst "
 /* the RE that catches security updates */
 #define SECURITY_RE "^[^\\(]*\\([^ ]* (Debian-Security:|Ubuntu:[^/]*/[^-]*-security)"
 
@@ -211,22 +213,18 @@ int run_upgrade(int *pkgcount, int *secpkgcount){
 	struct output chld_out, chld_err;
 	regex_t ireg, ereg, sreg;
 	char *cmdline=NULL, rerrbuf[64];
-	const char *include_ptr=NULL, *crit_ptr=NULL;
 
 	if(upgrade==NO_UPGRADE) return STATE_OK;
 
 	/* compile the regexps */
-	if(do_include!=NULL) include_ptr=do_include;
-	else include_ptr="^Inst";
-	if(do_critical!=NULL) crit_ptr=do_critical;
-	else crit_ptr=SECURITY_RE;
-
-	regres=regcomp(&ireg, include_ptr, REG_EXTENDED);
-	if(regres!=0) {
-		regerror(regres, &ireg, rerrbuf, 64);
-		die(STATE_UNKNOWN, _("%s: Error compiling regexp: %s"), progname, rerrbuf);
+	if (do_include != NULL) {
+		regres=regcomp(&ireg, do_include, REG_EXTENDED);
+		if (regres!=0) {
+			regerror(regres, &ireg, rerrbuf, 64);
+			die(STATE_UNKNOWN, _("%s: Error compiling regexp: %s"), progname, rerrbuf);
+		}
 	}
-
+   
 	if(do_exclude!=NULL){
 		regres=regcomp(&ereg, do_exclude, REG_EXTENDED);
 		if(regres!=0) {
@@ -235,6 +233,8 @@ int run_upgrade(int *pkgcount, int *secpkgcount){
 			    progname, rerrbuf);
 		}
 	}
+   
+	const char *crit_ptr = (do_critical != NULL) ? do_critical : SECURITY_RE;
 	regres=regcomp(&sreg, crit_ptr, REG_EXTENDED);
 	if(regres!=0) {
 		regerror(regres, &ereg, rerrbuf, 64);
@@ -269,7 +269,8 @@ int run_upgrade(int *pkgcount, int *secpkgcount){
 			printf("%s\n", chld_out.line[i]);
 		}
 		/* if it is a package we care about */
-		if(regexec(&ireg, chld_out.line[i], 0, NULL, 0)==0){
+		if (strncmp(PKGINST_PREFIX, chld_out.line[i], strlen(PKGINST_PREFIX)) == 0 &&
+		    (do_include == NULL || regexec(&ireg, chld_out.line[i], 0, NULL, 0) == 0)) {
 			/* if we're not excluding, or it's not in the
 			 * list of stuff to exclude */
 			if(do_exclude==NULL ||
@@ -298,7 +299,7 @@ int run_upgrade(int *pkgcount, int *secpkgcount){
 			}
 		}
 	}
-	regfree(&ireg);
+	if (do_include != NULL) regfree(&ireg);
 	regfree(&sreg);
 	if(do_exclude!=NULL) regfree(&ereg);
 	free(cmdline);
@@ -348,15 +349,15 @@ char* add_to_regexp(char *expr, const char *next){
 	char *re=NULL;
 
 	if(expr==NULL){
-		re=malloc(sizeof(char)*(strlen("^Inst () ")+strlen(next)+1));
+		re=malloc(sizeof(char)*(strlen("()")+strlen(next)+1));
 		if(!re) die(STATE_UNKNOWN, "malloc failed!\n");
-		sprintf(re, "^Inst (%s) ", next);
+		sprintf(re, "(%s)", next);
 	} else {
 		/* resize it, adding an extra char for the new '|' separator */
-		re=realloc(expr, sizeof(char)*strlen(expr)+1+strlen(next)+1);
+		re=realloc(expr, sizeof(char)*(strlen(expr)+1+strlen(next)+1));
 		if(!re) die(STATE_UNKNOWN, "realloc failed!\n");
 		/* append it starting at ')' in the old re */
-		sprintf((char*)(re+strlen(re)-2), "|%s) ", next);
+		sprintf((char*)(re+strlen(re)-1), "|%s)", next);
 	}
 
 	return re;