39 lines
1.0 KiB
C
39 lines
1.0 KiB
C
#define _GNU_SOURCE
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#include <dlfcn.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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/*
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* Noddy LD_PRELOAD wrapper to catch setsockopt calls, and log them to a file.
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*/
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typedef int (*real_setsockopt_t)(int sockfd, int level, int optname, const void *optval, socklen_t optlen);
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int real_setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t optlen)
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{
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return ((real_setsockopt_t)dlsym(RTLD_NEXT, "setsockopt"))(sockfd, level, optname, optval, optlen);
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}
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int setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t optlen)
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{
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FILE *fd;
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char *fn;
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int retval;
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retval = real_setsockopt(sockfd, level, optname, optval, optlen);
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fn = getenv("OUTPUT_setsockopt_logger");
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/*
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* Only interested in catching non-null 4-byte (integer) values
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*/
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if ( fn != NULL && optval != NULL && optlen == 4) {
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fd = fopen(fn,"a");
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fprintf(fd,"setsockopt:%i:%i:%i:%i:%i\n", sockfd, level, optname, *(int *)optval, retval);
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fclose(fd);
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}
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return retval;
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}
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