39f8dc43b7
Now that u[ret]probes can use name-based specification, it makes
sense to add support for auto-attach based on SEC() definition.
The format proposed is
SEC("u[ret]probe/binary:[raw_offset|[function_name[+offset]]")
For example, to trace malloc() in libc:
SEC("uprobe/libc.so.6:malloc")
...or to trace function foo2 in /usr/bin/foo:
SEC("uprobe//usr/bin/foo:foo2")
Auto-attach is done for all tasks (pid -1). prog can be an absolute
path or simply a program/library name; in the latter case, we use
PATH/LD_LIBRARY_PATH to resolve the full path, falling back to
standard locations (/usr/bin:/usr/sbin or /usr/lib64:/usr/lib) if
the file is not found via environment-variable specified locations.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-4-git-send-email-alan.maguire@oracle.com
86 lines
1.6 KiB
C
86 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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int my_tid;
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int kprobe_res;
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int kprobe_multi_res;
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int kretprobe_res;
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int uprobe_res;
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int uretprobe_res;
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int tp_res;
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int pe_res;
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static void update(void *ctx, int *res)
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{
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if (my_tid != (u32)bpf_get_current_pid_tgid())
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return;
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*res |= bpf_get_attach_cookie(ctx);
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}
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SEC("kprobe/sys_nanosleep")
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int handle_kprobe(struct pt_regs *ctx)
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{
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update(ctx, &kprobe_res);
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return 0;
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}
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SEC("kretprobe/sys_nanosleep")
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int handle_kretprobe(struct pt_regs *ctx)
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{
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update(ctx, &kretprobe_res);
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return 0;
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}
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SEC("uprobe")
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int handle_uprobe(struct pt_regs *ctx)
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{
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update(ctx, &uprobe_res);
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return 0;
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}
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SEC("uretprobe")
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int handle_uretprobe(struct pt_regs *ctx)
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{
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update(ctx, &uretprobe_res);
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return 0;
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}
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/* bpf_prog_array, used by kernel internally to keep track of attached BPF
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* programs to a given BPF hook (e.g., for tracepoints) doesn't allow the same
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* BPF program to be attached multiple times. So have three identical copies
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* ready to attach to the same tracepoint.
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*/
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SEC("tp/syscalls/sys_enter_nanosleep")
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int handle_tp1(struct pt_regs *ctx)
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{
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update(ctx, &tp_res);
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return 0;
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}
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SEC("tp/syscalls/sys_enter_nanosleep")
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int handle_tp2(struct pt_regs *ctx)
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{
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update(ctx, &tp_res);
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return 0;
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}
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SEC("tp/syscalls/sys_enter_nanosleep")
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int handle_tp3(void *ctx)
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{
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update(ctx, &tp_res);
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return 1;
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}
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SEC("perf_event")
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int handle_pe(struct pt_regs *ctx)
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{
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update(ctx, &pe_res);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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