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tools/: Add --json support #2

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Aug 2, 2021
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@mauriciovasquezbernal mauriciovasquezbernal commented Jul 23, 2021

Extend different tools to support output in json format.

TODO once merged:

@mauriciovasquezbernal mauriciovasquezbernal changed the base branch from master to gadget July 27, 2021 23:13
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Some questions

tools/execsnoop.py Outdated Show resolved Hide resolved
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@mauriciovasquezbernal mauriciovasquezbernal force-pushed the mauricio/execsnoop-json branch 2 times, most recently from 3ed6f4c to ea34dd9 Compare July 28, 2021 14:32
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I'm working to make this change to all gadgets supported by Inspektor Gadget. I'll update this soon.

@mauriciovasquezbernal mauriciovasquezbernal changed the title tools/execsnoop: Add --json and --file options tools/: Add --json support Jul 29, 2021
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I decided to split the work and only consider the --json flag in this PR. I also changed the implementation approach it to avoid having too many changes and making this PR new additions only.

The new idea disables standard output, all previous logic is still executed but it doesn't provide any visible output. There is a new code logic to print the events in json format when --json flag is passed.

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I added support for opensnoop that was missing and opened the corresponding PR on Inspektor Gadget to use this feature.

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Thanks! What's the output with --json when there is an error (e.g. compilation, verifier, permissions or "containers" map missing)?

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def stubprintb(s, file=sys.stdout, nl=1):
return

printb = stubprintb
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Is it possible to factor this in a function of bcc.containers? I am not sure if it works, maybe the function would have to be called before the printb import (from bcc.utils import printb) but after the bcc.containers` import...

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@mauriciovasquezbernal mauriciovasquezbernal Jul 30, 2021

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I created a disable_output helper in the bcc.utils package. The caller still has to assign the return value to printb but I think it's ok.

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if start_ts == 0:
start_ts = event.ts_us
eventJ = {
"time": ((float(event.ts_us) - start_ts) / 1000000),
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For another PR...

I know the same logic was in the initial code, but I wonder if we should use RFC3339 (2012-04-23T18:25:43.511Z).

import datetime
datetime.datetime.now().isoformat()

But I don't know how to convert the clock from bpf_ktime_get_ns() / CLOCK_MONOTONIC into the wall clock. Same problem with bpf_ktime_get_boot_ns() / CLOCK_BOOTTIME...

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I agree. This shouldn't be a relative time for the inspektor gadget use case. Let me open an issue to track this down.

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What's the output with --json when there is an error (e.g. compilation, verifier, permissions or "containers" map missing)?

The error is printed as usual to stderr.

Add this function that adds the container related info to an event.
This helper is useful for tools that support json output and want to
supress other kind of output without adding a lot of conditionals
everywhere. The function returns the original reference to sys.stdout
and a stub function to replace bcc.utils.printb().

If the tool uses printb, it should assign the returned stub to disable it:

stdout, printb = disable_stdout()

If the tool only uses print, then the stub can be ignored:

stdout, _ = disable_stdout()

The original reference to sys.stdout is saved on stdout and can be used
later on to print to stdout:

stdout.write("hi there...")
@mauriciovasquezbernal mauriciovasquezbernal merged commit 8f44a6d into gadget Aug 2, 2021
@mauriciovasquezbernal mauriciovasquezbernal deleted the mauricio/execsnoop-json branch August 2, 2021 13:11
eiffel-fl pushed a commit that referenced this pull request May 10, 2022
There are two pass managers in LLVM. Currently BCC uses the legacy one.
Switch to the new pass manager because the legacy one will be removed
in upcoming releases of LLVM.

Running the following script:
```

from bcc import BPF

bpf_text = '''
static int foobar()
{
    bpf_trace_printk("enter vfs_read");
    return 0;
}

KFUNC_PROBE(vfs_read)
{
    return foobar();
}
'''

BPF(text=bpf_text, debug=1)
```

The IR output is the same with or without this change using LLVM 15:

    ; ModuleID = 'sscanf'
    source_filename = "sscanf"
    ; ModuleID = '/virtual/main.c'
    source_filename = "/virtual/main.c"
    target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
    target triple = "bpf-pc-linux"

    @_version = dso_local global i32 332032, section "version", align 4, !dbg !0
    @_license = dso_local global [4 x i8] c"GPL\00", section "license", align 1, !dbg !5
    @__const.foobar._fmt = private unnamed_addr constant [15 x i8] c"enter vfs_read\00", align 1
    @llvm.compiler.used = appending global [2 x ptr] [ptr @_license, ptr @_version], section "llvm.metadata"

    ; Function Attrs: alwaysinline nounwind
    define dso_local i32 @kfunc__vfs_read(ptr nocapture noundef readnone %0) local_unnamed_addr #0 section ".bpf.fn.kfunc__vfs_read" !dbg !33 {
    %2 = alloca [15 x i8], align 1
    call void @llvm.dbg.value(metadata ptr %0, metadata !39, metadata !DIExpression()), !dbg !41
    call void @llvm.dbg.value(metadata ptr undef, metadata !42, metadata !DIExpression()) #4, !dbg !45
    call void @llvm.lifetime.start.p0(i64 15, ptr nonnull %2) #4, !dbg !47
    call void @llvm.dbg.declare(metadata ptr %2, metadata !53, metadata !DIExpression()) #4, !dbg !58
    call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 1 dereferenceable(15) %2, ptr noundef nonnull align 1 dereferenceable(15) @__const.foobar._fmt, i64 15, i1 false) #4, !dbg !58
    %3 = call i32 (ptr, i64, ...) inttoptr (i64 6 to ptr)(ptr noundef nonnull %2, i64 noundef 15) #4, !dbg !59
    call void @llvm.lifetime.end.p0(i64 15, ptr nonnull %2) #4, !dbg !60
    call void @llvm.dbg.value(metadata i32 0, metadata !40, metadata !DIExpression()), !dbg !41
    ret i32 0, !dbg !61
    }

    ; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
    declare void @llvm.dbg.declare(metadata, metadata, metadata) #1

    ; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
    declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2

    ; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
    declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2

    ; Function Attrs: alwaysinline argmemonly mustprogress nofree nounwind willreturn
    declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #3

    ; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
    declare void @llvm.dbg.value(metadata, metadata, metadata) #1

    attributes #0 = { alwaysinline nounwind "frame-pointer"="none" "min-legal-vector-width"="0" "no-jump-tables"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
    attributes #1 = { alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn }
    attributes #2 = { alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn }
    attributes #3 = { alwaysinline argmemonly mustprogress nofree nounwind willreturn }
    attributes #4 = { nounwind }

    !llvm.dbg.cu = !{!2}
    !llvm.module.flags = !{!27, !28, !29, !30, !31}
    !llvm.ident = !{!32}

    !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
    !1 = distinct !DIGlobalVariable(name: "_version", scope: !2, file: !14, line: 526, type: !26, isLocal: false, isDefinition: true)
    !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
    !3 = !DIFile(filename: "/virtual/main.c", directory: "/home/ubuntu/sources/bpf-next")
    !4 = !{!0, !5, !12}
    !5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
    !6 = distinct !DIGlobalVariable(name: "_license", scope: !2, file: !7, line: 26, type: !8, isLocal: false, isDefinition: true)
    !7 = !DIFile(filename: "/virtual/include/bcc/footer.h", directory: "")
    !8 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 32, elements: !10)
    !9 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
    !10 = !{!11}
    !11 = !DISubrange(count: 4)
    !12 = !DIGlobalVariableExpression(var: !13, expr: !DIExpression())
    !13 = distinct !DIGlobalVariable(name: "bpf_trace_printk_", scope: !2, file: !14, line: 542, type: !15, isLocal: true, isDefinition: true)
    !14 = !DIFile(filename: "/virtual/include/bcc/helpers.h", directory: "")
    !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !16, size: 64)
    !16 = !DISubroutineType(types: !17)
    !17 = !{!18, !19, !21, null}
    !18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
    !19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64)
    !20 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !9)
    !21 = !DIDerivedType(tag: DW_TAG_typedef, name: "u64", file: !22, line: 23, baseType: !23)
    !22 = !DIFile(filename: "include/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
    !23 = !DIDerivedType(tag: DW_TAG_typedef, name: "__u64", file: !24, line: 31, baseType: !25)
    !24 = !DIFile(filename: "include/uapi/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
    !25 = !DIBasicType(name: "unsigned long long", size: 64, encoding: DW_ATE_unsigned)
    !26 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
    !27 = !{i32 7, !"Dwarf Version", i32 4}
    !28 = !{i32 2, !"Debug Info Version", i32 3}
    !29 = !{i32 1, !"wchar_size", i32 4}
    !30 = !{i32 7, !"PIC Level", i32 2}
    !31 = !{i32 7, !"PIE Level", i32 2}
    !32 = !{!"Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435"}
    !33 = distinct !DISubprogram(name: "kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 23, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !38)
    !34 = !DIFile(filename: "/virtual/main.c", directory: "")
    !35 = !DISubroutineType(types: !36)
    !36 = !{!18, !37}
    !37 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !25, size: 64)
    !38 = !{!39, !40}
    !39 = !DILocalVariable(name: "ctx", arg: 1, scope: !33, file: !34, line: 23, type: !37)
    !40 = !DILocalVariable(name: "__ret", scope: !33, file: !34, line: 23, type: !18)
    !41 = !DILocation(line: 0, scope: !33)
    !42 = !DILocalVariable(name: "ctx", arg: 1, scope: !43, file: !34, line: 23, type: !37)
    !43 = distinct !DISubprogram(name: "____kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 24, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !44)
    !44 = !{!42}
    !45 = !DILocation(line: 0, scope: !43, inlinedAt: !46)
    !46 = distinct !DILocation(line: 23, column: 1, scope: !33)
    !47 = !DILocation(line: 15, column: 5, scope: !48, inlinedAt: !57)
    !48 = distinct !DILexicalBlock(scope: !49, file: !34, line: 15, column: 3)
    !49 = distinct !DISubprogram(name: "foobar", scope: !34, file: !34, line: 13, type: !50, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !52)
    !50 = !DISubroutineType(types: !51)
    !51 = !{!18}
    !52 = !{!53}
    !53 = !DILocalVariable(name: "_fmt", scope: !48, file: !34, line: 15, type: !54)
    !54 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 120, elements: !55)
    !55 = !{!56}
    !56 = !DISubrange(count: 15)
    !57 = distinct !DILocation(line: 25, column: 9, scope: !43, inlinedAt: !46)
    !58 = !DILocation(line: 15, column: 10, scope: !48, inlinedAt: !57)
    !59 = !DILocation(line: 15, column: 37, scope: !48, inlinedAt: !57)
    !60 = !DILocation(line: 15, column: 76, scope: !49, inlinedAt: !57)
    !61 = !DILocation(line: 23, column: 1, scope: !33)

Closes iovisor#3947.

References:
  [0]: https://llvm.org/docs/NewPassManager.html
  [1]: https://blog.llvm.org/posts/2021-03-26-the-new-pass-manager/

Signed-off-by: Hengqi Chen <chenhengqi@outlook.com>
mauriciovasquezbernal pushed a commit that referenced this pull request Dec 20, 2022
…for -v option

Add additional information and change format of backtrace
- add symbol base offset, dso name, dso base offset
- symbol and dso info is included if it's available in target binary
- changed format:
INDEX ADDR [SYMBOL+OFFSET] (MODULE+OFFSET)

Print backtrace of ip if it failed to get syms.

Before:
  # offcputime -v
    psiginfo
    vscanf
    __snprintf_chk
    [unknown]
    [unknown]
    [unknown]
    [unknown]
    [unknown]
    sd_event_exit
    sd_event_dispatch
    sd_event_run
    [unknown]
    __libc_start_main
    [unknown]
    -                systemd-journal (204)
        1

    xas_load
    xas_find
    filemap_map_pages
    __handle_mm_fault
    handle_mm_fault
    do_page_fault
    do_translation_fault
    do_mem_abort
    do_el0_ia_bp_hardening
    el0_ia
    xas_load
    --
failed to get syms
      -                PmLogCtl (138757)
        1

After:
  # offcputime -v
    #0  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
    #1  0xffffffc01009a93c el0_svc_handler+0x34
    #2  0xffffffc010084a08 el0_svc+0x8
    #3  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
    --
    #4  0x0000007fa0bffd14 clock_nanosleep+0x94 (/usr/lib/libc-2.31.so+0x9ed14)
    #5  0x0000007fa0c0530c nanosleep+0x1c (/usr/lib/libc-2.31.so+0xa430c)
    #6  0x0000007fa0c051e4 sleep+0x34 (/usr/lib/libc-2.31.so+0xa41e4)
    #7  0x000000558a5a9608 flb_loop+0x28 (/usr/bin/fluent-bit+0x52608)
    #8  0x000000558a59f1c4 flb_main+0xa84 (/usr/bin/fluent-bit+0x481c4)
    #9  0x0000007fa0b85124 __libc_start_main+0xe4 (/usr/lib/libc-2.31.so+0x24124)
    #10 0x000000558a59d828 _start+0x34 (/usr/bin/fluent-bit+0x46828)
    -                fluent-bit (1238)
        1

    #0  0xffffffc01027daa4 generic_copy_file_checks+0x334
    #1  0xffffffc0102ba634 __handle_mm_fault+0x8dc
    #2  0xffffffc0102baa20 handle_mm_fault+0x168
    #3  0xffffffc010ad23c0 do_page_fault+0x148
    #4  0xffffffc010ad27c0 do_translation_fault+0xb0
    #5  0xffffffc0100816b0 do_mem_abort+0x50
    #6  0xffffffc0100843b0 el0_da+0x1c
    #7  0xffffffc01027daa4 generic_copy_file_checks+0x334
    --
    #8  0x0000007f8dc12648 [unknown]
    #9  0x0000007f8dc0aef8 [unknown]
    #10 0x0000007f8dc1c990 [unknown]
    #11 0x0000007f8dc08b0c [unknown]
    #12 0x0000007f8dc08e48 [unknown]
    #13 0x0000007f8dc081c8 [unknown]
    -                PmLogCtl (2412)
        1

Fixed: iovisor#3884
Signed-off-by: Eunseon Lee <es.lee@lge.com>
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