8f870c233f
* only shim v2 runc v2 ("io.containerd.runc.v2") is supported
* only PID metrics is implemented. Others should be implemented in separate PRs.
* lots of code duplication in v1 metrics and v2 metrics. Dedupe should be separate PR.
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
59 lines
1.4 KiB
Go
59 lines
1.4 KiB
Go
package ebpf
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import (
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"github.com/cilium/ebpf/asm"
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)
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// link resolves bpf-to-bpf calls.
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//
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// Each section may contain multiple functions / labels, and is only linked
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// if the program being edited references one of these functions.
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//
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// Sections must not require linking themselves.
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func link(insns asm.Instructions, sections ...asm.Instructions) (asm.Instructions, error) {
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for _, section := range sections {
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var err error
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insns, err = linkSection(insns, section)
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if err != nil {
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return nil, err
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}
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}
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return insns, nil
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}
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func linkSection(insns, section asm.Instructions) (asm.Instructions, error) {
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// A map of symbols to the libraries which contain them.
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symbols, err := section.SymbolOffsets()
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if err != nil {
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return nil, err
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}
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for _, ins := range insns {
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if ins.Reference == "" {
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continue
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}
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if ins.OpCode.JumpOp() != asm.Call || ins.Src != asm.R1 {
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continue
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}
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if ins.Constant != -1 {
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// This is already a valid call, no need to link again.
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continue
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}
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if _, ok := symbols[ins.Reference]; !ok {
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// Symbol isn't available in this section
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continue
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}
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// At this point we know that at least one function in the
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// library is called from insns. Merge the two sections.
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// The rewrite of ins.Constant happens in asm.Instruction.Marshal.
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return append(insns, section...), nil
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}
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// None of the functions in the section are called. Do nothing.
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return insns, nil
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}
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