50 lines
1.1 KiB
C
50 lines
1.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* bpf-script-test-prologue.c
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* Test BPF prologue
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*/
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#ifndef LINUX_VERSION_CODE
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# error Need LINUX_VERSION_CODE
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# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
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#endif
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#define SEC(NAME) __attribute__((section(NAME), used))
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#include <uapi/linux/fs.h>
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/*
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* If CONFIG_PROFILE_ALL_BRANCHES is selected,
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* 'if' is redefined after include kernel header.
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* Recover 'if' for BPF object code.
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*/
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#ifdef if
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# undef if
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#endif
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typedef unsigned int __bitwise fmode_t;
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#define FMODE_READ 0x1
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#define FMODE_WRITE 0x2
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static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
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(void *) 6;
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SEC("func=null_lseek file->f_mode offset orig")
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int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode,
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unsigned long offset, unsigned long orig)
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{
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fmode_t f_mode = (fmode_t)_f_mode;
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if (err)
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return 0;
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if (f_mode & FMODE_WRITE)
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return 0;
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if (offset & 1)
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return 0;
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if (orig == SEEK_CUR)
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return 0;
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return 1;
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}
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char _license[] SEC("license") = "GPL";
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int _version SEC("version") = LINUX_VERSION_CODE;
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