Fix btt to handle large numbers of output files

[blktrace.git] / btt / misc.c

diff --git a/btt/misc.c b/btt/misc.c
index 0ddd26003c82ff64dcca2161e15849870842a8b4..c79da2c3991997c8a76143100be3ad6cb37641ee 100644 (file)
--- a/btt/misc.c
+++ b/btt/misc.c
@@ -18,11 +18,14 @@
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  */
+#include <errno.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <unistd.h>
+#include <sys/time.h>
+#include <sys/resource.h>
 
 #define INLINE_DECLARE
 #include "globals.h"
@@ -116,4 +119,45 @@ char *make_dev_hdr(char *pad, size_t len, struct d_info *dip, int add_parens)
        return pad;
 }
 
+/*
+ * Due to the N(devs) parts of a lot of the output features provided
+ * by btt, it will fail opens on large(ish) systems. Here we try to
+ * keep bumping our open file limits, and if those fail, we return NULL.
+ *
+ * Root users will probably be OK with this, others...
+ */
+FILE *my_fopen(const char *path, const char *mode)
+{
+       FILE *fp;
+
+       fp = fopen(path, mode);
+       while (fp == NULL) {
+               if (errno == ENFILE || errno == EMFILE) {
+                       struct rlimit rlim;
+
+                       if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
+                               perror("get: RLIMIT_NOFILE");
+                               return NULL;
+                       }
+
+                       rlim.rlim_cur++;
+                       if (rlim.rlim_cur >= rlim.rlim_max)
+                               rlim.rlim_max++;
+
+                       if (setrlimit(RLIMIT_NOFILE, &rlim) < 0) {
+                               perror("set: RLIMIT_NOFILE");
+                               return NULL;
+                       }
+               }
+               else {
+                       perror(path);
+                       return NULL;
+               }
+
+               fp = fopen(path, mode);
+       }
+
+       return fp;
+}
+
 void dbg_ping(void) {}