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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
commit | 5e61585d76ae77fd5e9e96ebabb57afa4d74880d (patch) | |
tree | 2b467823aaeebc7ef8bc9e3cabe8074eaef1666d /src/util/timed_read.c | |
parent | Initial commit. (diff) | |
download | postfix-upstream/3.5.24.tar.xz postfix-upstream/3.5.24.zip |
Adding upstream version 3.5.24.upstream/3.5.24upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/util/timed_read.c')
-rw-r--r-- | src/util/timed_read.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/util/timed_read.c b/src/util/timed_read.c new file mode 100644 index 0000000..fdae8fa --- /dev/null +++ b/src/util/timed_read.c @@ -0,0 +1,86 @@ +/*++ +/* 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); + } + } +} |