47 lines
995 B
C
47 lines
995 B
C
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/*
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* gcc fopen_failure.c -o fopen_failure.so -shared -ldl
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* LD_PRELOAD=./fopen_failure.so FAILURE_PATH=/etc/shadow ./test /etc/shadow
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*/
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#define _GNU_SOURCE
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#include <dlfcn.h>
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#include <errno.h>
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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typedef FILE * (*fopen_type) (const char *path, const char *mode);
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static fopen_type next_fopen;
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static const char *failure_path = NULL;
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FILE *fopen64 (const char *path, const char *mode)
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{
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printf ("fopen64(%s, %s)\n", path, mode);
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if (NULL == next_fopen)
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{
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next_fopen = dlsym (RTLD_NEXT, "fopen64");
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assert (NULL != next_fopen);
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}
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if (NULL == failure_path) {
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failure_path = getenv ("FAILURE_PATH");
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if (NULL == failure_path) {
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fputs ("No FAILURE_PATH defined\n", stderr);
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}
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}
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if ( (NULL != path)
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&& (NULL != failure_path)
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&& (strcmp (path, failure_path) == 0))
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{
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fprintf (stderr, "fopen64 FAILURE %s %s ...\n", path, mode);
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errno = EIO;
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return NULL;
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}
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return next_fopen (path, mode);
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}
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