Patch from tito to replace shared memory usage with mlock(), slightly tweaked

by me.

diff --git a/miscutils/hdparm.c b/miscutils/hdparm.c
index bf24a2d3ae183f4f13fb3f32bc697c857cbbdfa7..457cf96701098cc2581ab4b551dd6704a1821df5 100644 (file)
--- a/miscutils/hdparm.c
+++ b/miscutils/hdparm.c
@@ -25,6 +25,7 @@
 #include <sys/time.h>
 #include <sys/times.h>
 #include <sys/mount.h>
+#include <sys/mman.h>
 #include <getopt.h>
 #include "busybox.h"
 #include <linux/types.h>
@@ -1406,36 +1407,20 @@ static void do_time(int flag, int fd)
        flag = 1 time_device
 */
 {
-       char *buf;
        struct itimerval e1, e2;
-       int shmid;
        double elapsed, elapsed2;
        unsigned int max_iterations = 1024, total_MB, iterations;
        unsigned long long blksize;
+       RESERVE_CONFIG_BUFFER(buf, TIMING_BUF_BYTES);
 
-       if (0 == do_blkgetsize(fd, &blksize)) {
-               max_iterations = blksize / (2 * 1024) / TIMING_BUF_MB;
+       if (mlock(buf, TIMING_BUF_BYTES)) {
+               bb_perror_msg("mlock");
+               goto quit2;
        }
 
-       if ((shmid = shmget(IPC_PRIVATE, TIMING_BUF_BYTES, 0600)) == -1)
-       {
-               bb_perror_msg("shmget"); /*"could not allocate sharedmem buf"*/
-               return;
-       }
-       if (shmctl(shmid, SHM_LOCK, NULL) == -1)
-       {
-               bb_perror_msg("shmctl"); /*"could not lock sharedmem buf"*/
-               (void) shmctl(shmid, IPC_RMID, NULL);
-               return;
-       }
-       if ((buf = shmat(shmid, (char *) 0, 0)) == (char *) -1)
-       {
-               bb_perror_msg("shmat"); /*"could not attach sharedmem buf"*/
-               (void) shmctl(shmid, IPC_RMID, NULL);
-               return;
+       if (0 == do_blkgetsize(fd, &blksize)) {
+               max_iterations = blksize / (2 * 1024) / TIMING_BUF_MB;
        }
-       if (shmctl(shmid, IPC_RMID, NULL) == -1)
-               bb_perror_msg("shmctl");
 
        /* Clear out the device request queues & give them time to complete */
        sync();
@@ -1505,8 +1490,9 @@ static void do_time(int flag, int fd)
                print_timing(total_MB, elapsed);
        }
 quit:
-       if (-1 == shmdt(buf))
-               bb_perror_msg("shmdt"); /*"could not detach sharedmem buf"*/
+       munlock(buf, TIMING_BUF_BYTES);
+quit2:
+       RELEASE_CONFIG_BUFFER(buf);
 }
 
 static void on_off (unsigned int value)