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authorDenis Vlasenko2007-09-27 10:09:59 +0000
committerDenis Vlasenko2007-09-27 10:09:59 +0000
commit5d61e71c3a8ac3296afbfe9a014c62050c5a9234 (patch)
treee9ab2cd35d1f2d51b26a678551a0439b1719928b /libbb/safe_poll.c
parentc9dc2ac578278e86be248cc21e53081f7054da83 (diff)
downloadbusybox-5d61e71c3a8ac3296afbfe9a014c62050c5a9234.zip
busybox-5d61e71c3a8ac3296afbfe9a014c62050c5a9234.tar.gz
introduce safe_poll (fixes a problem in top)
function old new delta safe_poll - 77 +77 svlogd_main 1470 1466 -4 zcip_main 1530 1524 -6 forkexec 1345 1338 -7 decode_format_string 795 788 -7 collect_blk 474 467 -7 buffer_pread 540 532 -8 tftp 1182 1172 -10 microcom_main 763 749 -14 arpping 441 424 -17 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/9 up/down: 77/-80) Total: -3 bytes text data bss dec hex filename 770162 1034 10404 781600 bed20 busybox_old 770158 1034 10404 781596 bed1c busybox_unstripped
Diffstat (limited to 'libbb/safe_poll.c')
-rw-r--r--libbb/safe_poll.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/libbb/safe_poll.c b/libbb/safe_poll.c
new file mode 100644
index 0000000..d2b773c
--- /dev/null
+++ b/libbb/safe_poll.c
@@ -0,0 +1,34 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 2007 by Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+
+/* Wrapper which restarts poll on EINTR or ENOMEM.
+ * On other errors does perror("poll") and returns.
+ * Warning! May take longer than timeout_ms to return! */
+int safe_poll(struct pollfd *ufds, nfds_t nfds, int timeout)
+{
+ while (1) {
+ int n = poll(ufds, nfds, timeout);
+ if (n >= 0)
+ return n;
+ /* Make sure we inch towards completion */
+ if (timeout > 0)
+ timeout--;
+ /* E.g. strace causes poll to return this */
+ if (errno == EINTR)
+ continue;
+ /* Kernel is very low on memory. Retry. */
+ /* I doubt many callers would handle this correctly! */
+ if (errno == ENOMEM)
+ continue;
+ bb_perror_msg("poll");
+ return n;
+ }
+}