From db9187c8d21e9f08b20899e3e14c1938db7b79fb Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Thu, 25 Jul 2019 14:07:16 +0200 Subject: libutil: add read_data style wrapper around pread() Signed-off-by: David Oberhollenzer --- lib/util/read_data_at.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 lib/util/read_data_at.c (limited to 'lib/util') diff --git a/lib/util/read_data_at.c b/lib/util/read_data_at.c new file mode 100644 index 0000000..98432d9 --- /dev/null +++ b/lib/util/read_data_at.c @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +#include "config.h" + +#include +#include +#include + +#include "util.h" + +int read_data_at(const char *errstr, off_t location, int fd, + void *buffer, size_t size) +{ + ssize_t ret; + + while (size > 0) { + ret = pread(fd, buffer, size, location); + if (ret < 0) { + if (errno == EINTR) + continue; + perror(errstr); + return -1; + } + if (ret == 0) { + fprintf(stderr, "%s: short read\n", errstr); + return -1; + } + + size -= ret; + buffer = (char *)buffer + ret; + location += ret; + } + + return 0; +} -- cgit v1.2.3