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92 lines
1.8 KiB
92 lines
1.8 KiB
#define _GNU_SOURCE
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#include<stdio.h>
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#include<stdlib.h>
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#include<string.h>
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#include<unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include<sys/mman.h>
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#include<fcntl.h>
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#define FILEMODE S_IRWXU | S_IRGRP | S_IROTH
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#define DEFAULT_ADVICE MADV_SEQUENTIAL
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#define ADVICE DEFAULT_ADVICE | MADV_WILLNEED
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#define UNADVICE MADV_NORMAL | MADV_COLD
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#include <map.h>
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static inline int _map_advise(const mmap_t* restrict map, int adv)
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{
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return madvise(map->ptr, map->len, adv);
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}
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int unset_preload_map(mmap_t* restrict map, int freeing)
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{
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if(_map_advise(map, UNADVICE | (freeing ? MADV_DONTNEED : 0)) != 0) {
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perror("failed to advise kernel to drop mapped page(s)");
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return 0;
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}
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return 1;
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}
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int set_preload_map(mmap_t* restrict map)
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{
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if(_map_advise(map, ADVICE) != 0) {
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perror("failed to advise kernel to preload mapped page(s)");
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return 0;
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}
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return 1;
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}
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int open_and_map(const char* file, mmap_t* restrict ptr)
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{
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int fd;
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struct stat st;
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if ((fd = open(file, O_RDONLY, FILEMODE)) < 0) {
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perror("Failed to open file");
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return 0;
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}
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if (fstat(fd, &st) < 0) {
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perror("Failed to stat file");
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close(fd);
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return 0;
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}
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struct mmap map = { .fd = fd, .ptr = NULL, .len = st.st_size };
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if ((map.ptr = mmap(NULL, map.len, PROT_READ, MAP_SHARED,fd, 0)) == MAP_FAILED) {
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perror("mmap() failed");
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close(fd);
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return 0;
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}
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if(_map_advise(&map, DEFAULT_ADVICE) != 0) {
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perror("madvise(): failed to set default advice");
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//XXX: Should this be a hard error, or should we return the map if this fails anyway?
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unmap_and_close(map);
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return 0;
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}
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*ptr = map;
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return 1;
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}
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int unmap_and_close(mmap_t map)
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{
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if (munmap(map.ptr, map.len) < 0) {
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perror("munmap() failed");
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return 0;
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}
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if (close(map.fd) <0) {
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perror("Failed to close fd");
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return 0;
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}
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return 1;
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}
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