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-rw-r--r--src/util/timed_read.c86
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diff --git a/src/util/timed_read.c b/src/util/timed_read.c
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+/*++
+/* NAME
+/* timed_read 3
+/* SUMMARY
+/* read operation with pre-read timeout
+/* SYNOPSIS
+/* #include <iostuff.h>
+/*
+/* ssize_t timed_read(fd, buf, len, timeout, context)
+/* int fd;
+/* void *buf;
+/* size_t len;
+/* int timeout;
+/* void *context;
+/* DESCRIPTION
+/* timed_read() performs a read() operation when the specified
+/* descriptor becomes readable within a user-specified deadline.
+/*
+/* Arguments:
+/* .IP fd
+/* File descriptor in the range 0..FD_SETSIZE.
+/* .IP buf
+/* Read buffer pointer.
+/* .IP len
+/* Read buffer size.
+/* .IP timeout
+/* The deadline in seconds. If this is <= 0, the deadline feature
+/* is disabled.
+/* .IP context
+/* Application context. This parameter is unused. It exists only
+/* for the sake of VSTREAM compatibility.
+/* DIAGNOSTICS
+/* When the operation does not complete within the deadline, the
+/* result value is -1, and errno is set to ETIMEDOUT.
+/* All other returns are identical to those of a read(2) operation.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <unistd.h>
+#include <errno.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <iostuff.h>
+
+/* timed_read - read with deadline */
+
+ssize_t timed_read(int fd, void *buf, size_t len,
+ int timeout, void *unused_context)
+{
+ ssize_t ret;
+
+ /*
+ * Wait for a limited amount of time for something to happen. If nothing
+ * happens, report an ETIMEDOUT error.
+ *
+ * XXX Solaris 8 read() fails with EAGAIN after read-select() returns
+ * success.
+ */
+ for (;;) {
+ if (timeout > 0 && read_wait(fd, timeout) < 0)
+ return (-1);
+ if ((ret = read(fd, buf, len)) < 0 && timeout > 0 && errno == EAGAIN) {
+ msg_warn("read() returns EAGAIN on a readable file descriptor!");
+ msg_warn("pausing to avoid going into a tight select/read loop!");
+ sleep(1);
+ continue;
+ } else if (ret < 0 && errno == EINTR) {
+ continue;
+ } else {
+ return (ret);
+ }
+ }
+}