libbb: create and use mmap() helpers

function                                             old     new   delta
mmap_anon                                              -      22     +22
mmap_read                                              -      21     +21
xmmap_anon                                             -      16     +16
rpm_gettags                                          465     447     -18
bb_full_fd_action                                    498     480     -18
uevent_main                                          337     310     -27
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 0/3 up/down: 59/-63)             Total: -4 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/util-linux/uevent.c b/util-linux/uevent.c
index 045b35432..015f1ee78 100644
--- a/util-linux/uevent.c
+++ b/util-linux/uevent.c
@@ -74,12 +74,7 @@ int uevent_main(int argc UNUSED_PARAM, char **argv)
                 // for a new uevent notification to come in.
                 // We use a fresh mmap so that buffer is not allocated
                 // until kernel actually starts filling it.
-                netbuf = mmap(NULL, USER_RCVBUF,
-                                        PROT_READ | PROT_WRITE,
-                                        MAP_PRIVATE | MAP_ANON,
-                                        /* ignored: */ -1, 0);
-                if (netbuf == MAP_FAILED)
-                        bb_simple_perror_msg_and_die("mmap");
+                netbuf = xmmap_anon(USER_RCVBUF);
 
                 // Here we block, possibly for a very long time
                 len = safe_read(fd, netbuf, USER_RCVBUF - 1);