busybox/miscutils/readahead.c

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/* vi: set sw=4 ts=4: */
/*
* readahead implementation for busybox
*
* Preloads the given files in RAM, to reduce access time.
* Does this by calling the readahead(2) system call.
*
* Copyright (C) 2006 Michael Opdenacker <michael@free-electrons.com>
*
* Licensed under GPLv2 or later, see file License in this tarball for details.
*/
#include "libbb.h"
int readahead_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int readahead_main(int argc, char **argv)
{
int retval = EXIT_SUCCESS;
if (argc == 1) bb_show_usage();
while (*++argv) {
int fd = open_or_warn(*argv, O_RDONLY);
if (fd >= 0) {
off_t len;
int r;
/* fdlength was reported to be unreliable - use seek */
len = xlseek(fd, 0, SEEK_END);
xlseek(fd, 0, SEEK_SET);
r = readahead(fd, 0, len);
close(fd);
if (r >= 0)
continue;
}
retval = EXIT_FAILURE;
}
return retval;
}