Fix print_multipath_topology for large outputs

print_multipath_topology had a hard size limit. With a large number
of LUNs and a large number of paths, it was possible to go over
this limit, and have some of the output cut off.
print_multipath_topology now checks for this, and resizes the
buffer if necessary.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

diff --git a/libmultipath/print.c b/libmultipath/print.c
index 0e2c680..274f5e7 100644 (file)
--- a/libmultipath/print.c
+++ b/libmultipath/print.c
@@ -8,6 +8,8 @@
 #include <sys/stat.h>
 #include <dirent.h>
 #include <unistd.h>
+#include <string.h>
+#include <errno.h>
 
 #include "checkers.h"
 #include "vector.h"
@@ -24,6 +26,7 @@
 #include "switchgroup.h"
 #include "devmapper.h"
 #include "uevent.h"
+#include "debug.h"
 
 #define MAX(x,y) (x > y) ? x : y
 #define TAIL     (line + len - 1 - c)
@@ -754,11 +757,30 @@ snprint_pathgroup (char * line, int len, char * format,
 extern void
 print_multipath_topology (struct multipath * mpp, int verbosity)
 {
-       char buff[MAX_LINE_LEN * MAX_LINES] = {};
+       int resize;
+       char *buff = NULL;
+       char *old = NULL;
+       int len, maxlen = MAX_LINE_LEN * MAX_LINES;
+
+       buff = MALLOC(maxlen);
+       do {
+               if (!buff) {
+                       if (old)
+                               FREE(old);
+                       condlog(0, "couldn't allocate memory for list: %s\n",
+                               strerror(errno));
+                       return;
+               }
+
+               len = snprint_multipath_topology(buff, maxlen, mpp, verbosity);
+               resize = (len == maxlen - 1);
 
-       memset(&buff[0], 0, MAX_LINE_LEN * MAX_LINES);
-       snprint_multipath_topology(&buff[0], MAX_LINE_LEN * MAX_LINES,
-                                  mpp, verbosity);
+               if (resize) {
+                       maxlen *= 2;
+                       old = buff;
+                       buff = REALLOC(buff, maxlen);
+               }
+       } while (resize);
        printf("%s", buff);
 }