mirror of
https://github.com/checkpoint-restore/criu
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32 lines
830 B
C
32 lines
830 B
C
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#define _GNU_SOURCE
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#include <unistd.h>
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#include <dlfcn.h>
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#include <errno.h>
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ssize_t (*original_pread)(int fd, void *buf, size_t count, off_t offset) = NULL;
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/**
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* This function is a wrapper around pread() that is used for testing CRIU's
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* handling of cases where pread() returns less data than requested.
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*
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* pmc_fill() in criu/pagemap.c is a good example of where this can happen.
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*/
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ssize_t pread64(int fd, void *buf, size_t count, off_t offset)
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{
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if (!original_pread) {
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original_pread = dlsym(RTLD_NEXT, "pread");
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if (!original_pread) {
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errno = EIO;
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return -1;
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}
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}
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/* The following aims to simulate the case when pread() returns less
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* data than requested. We need to ensure that CRIU handles such cases. */
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if (count > 2048) {
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count -= 1024;
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}
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return original_pread(fd, buf, count, offset);
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}
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