11871 smatch should not hammer linux procfs path
Reviewed by: John Levon <john.levon@joyent.com>

@@ -14,31 +14,36 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  */
 
 #include "smatch.h"
+#include <fcntl.h>
 #include <unistd.h>
+#include <sys/procfs.h>
 
 static int my_id;
+static int my_fd = -2;
 
 static unsigned long max_size;
 
 unsigned long get_mem_kb(void)
 {
-        FILE *file;
-        char buf[1024];
-        unsigned long size;
+        prpsinfo_t pbuf;
 
-        file = fopen("/proc/self/statm", "r");
-        if (!file)
-                return 0;
-        fread(buf, 1, sizeof(buf), file);
-        fclose(file);
+        if (my_fd == -2) {
+                /* Do not repeatedly attempt this if it fails. */
+                my_fd = open("/proc/self/psinfo", O_RDONLY);
+        }
+        if (my_fd == -1) {
+                return (0);
+        }
 
-        size = strtoul(buf, NULL, 10);
-        size = size * sysconf(_SC_PAGESIZE) / 1024;
-        return size;
+        if (pread(my_fd, &pbuf, sizeof (pbuf), 0) != sizeof (pbuf)) {
+                return (0);
+        }
+
+        return (pbuf.pr_rssize);
 }
 
 static void match_end_func(struct symbol *sym)
 {
         unsigned long size;