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Add /proc/modules support #476

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109 changes: 109 additions & 0 deletions proc_modules.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,109 @@
// Copyright 2022 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package procfs

import (
"bufio"
"bytes"
"fmt"
"io"
"strconv"
"strings"

"github.com/prometheus/procfs/internal/util"
)

// Module represents a single module info in the kernel.
type Module struct {
// Name is the name of the module.
Name string
// Size is the memory size of the module, in bytes
Size uint64
// Instances is the number of instances of the module are currently loaded.
// A value of zero represents an unloaded module.
Instances uint64
// Dependencies is the list of modules that this module depends on.
Dependencies []string
// State is the state of the module is in: Live, Loading, or Unloading are the only possible values.
State string
// Offset is a memory offset for the loaded module
Offset uint64
// Taints is a list of taints that the module has.
Taints []string
}

// Modules represents a list of Module structs.
type Modules []Module

// Modules parses the metrics from /proc/modules file and returns a slice of
// structs containing the relevant info.
func (fs FS) Modules() ([]Module, error) {
data, err := util.ReadFileNoStat(fs.proc.Path("modules"))
if err != nil {
return nil, err
}
return parseModules(bytes.NewReader(data))
}

// parseModules parses the metrics from /proc/modules file
// and returns a []Module structure.
// - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/4/html/reference_guide/s2-proc-modules
// - https://unix.stackexchange.com/a/152527/300614
func parseModules(r io.Reader) ([]Module, error) {
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var (
scanner = bufio.NewScanner(r)
modules = make([]Module, 0)
)

for scanner.Scan() {
parts := strings.Fields(scanner.Text())
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if len(parts) < 6 {
return nil, fmt.Errorf("not enough fields in modules (expected at least 6 fields but got %d): %s", len(parts), parts)
}

module := Module{
Name: parts[0],
Dependencies: []string{},
State: parts[4],
Taints: []string{},
}

if size, err := strconv.ParseUint(parts[1], 10, 64); err == nil {
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Is it expected that the parsing might fail? If not, we should just abort here and return the error then silentely ignoring it.

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Is it expected that the parsing might fail?

Yes, I think it's possible. Checking the error could also prevent from spec changes. (too low possibility, but still would be better than not checking instead.)

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yeah but I don't like that we silentely ignore the error here. Why not return an error if err != nil?

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Why not return an error if err != nil?

That's because I noticed this err == nil pattern in some places. For example, arp:

procfs/arp.go

Line 98 in 0c4b3aa

if mac, err := net.ParseMAC(columns[3]); err == nil {
zoneinfo:

procfs/zoneinfo.go

Line 186 in 0c4b3aa

if err == nil {

I agree with you, returning an error would better. I can return an error if you want. Wdyt?

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@SuperQ wdyt? But yeah I think returning an error would be better

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Yes, returning the error would be better.

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@Dentrax Can you change this so we can merge it?

module.Size = size
}

if instances, err := strconv.ParseUint(parts[2], 10, 64); err == nil {
module.Instances = instances
}

dependencies := parts[3]
if dependencies != "-" {
module.Dependencies = strings.Split(strings.TrimSuffix(dependencies, ","), ",")
}

if offset, err := strconv.ParseUint(parts[5], 10, 64); err == nil {
module.Offset = offset
}

// Kernel Taint State is available if parts length is greater than 6.
if len(parts) > 6 {
taints := strings.TrimSuffix(strings.TrimPrefix(parts[6], "("), ")")
module.Taints = strings.Split(taints, "")
}

modules = append(modules, module)
}

return modules, scanner.Err()
}
97 changes: 97 additions & 0 deletions proc_modules_test.go
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Original file line number Diff line number Diff line change
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// Copyright 2022 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package procfs

import (
"reflect"
"testing"
)

func TestProcModules(t *testing.T) {
fs := getProcFixtures(t)

modules, err := fs.Modules()
if err != nil {
t.Fatal(err)
}

if want, have := 89, len(modules); want != have {
t.Errorf("want length %d, have %d", want, have)
}

for _, test := range []struct {
name string
index int
want Module
}{
{
name: "no dependencies and taints",
index: 0,
want: Module{
Name: "nft_counter",
Size: 16384,
Instances: 4,
Dependencies: []string{},
State: "Live",
Offset: 0,
Taints: []string{},
},
},
{
name: "have dependencies with no taints",
index: 11,
want: Module{
Name: "nf_tables",
Size: 245760,
Instances: 19,
Dependencies: []string{"nft_counter", "nft_chain_nat", "nft_compat"},
State: "Live",
Offset: 0,
Taints: []string{},
},
},
{
name: "have multiple taints with multiple dependencies",
index: 83,
want: Module{
Name: "drm",
Size: 622592,
Instances: 3,
Dependencies: []string{"virtio_gpu", "drm_kms_helper"},
State: "Live",
Offset: 0,
Taints: []string{"P", "O", "E"},
},
},
{
name: "have single taint with single dependency",
index: 88,
want: Module{
Name: "failover",
Size: 16384,
Instances: 1,
Dependencies: []string{"net_failover"},
State: "Live",
Offset: 0,
Taints: []string{"P"},
},
},
} {
t.Run(test.name, func(t *testing.T) {
if want, have := test.want, modules[test.index]; !reflect.DeepEqual(want, have) {
t.Errorf("want %v, have %v", want, have)
}
})
}
}
93 changes: 93 additions & 0 deletions testdata/fixtures.ttar
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Original file line number Diff line number Diff line change
Expand Up @@ -2258,6 +2258,99 @@ DirectMap4k: 91136 kB
DirectMap2M: 16039936 kB
Mode: 664
# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Path: fixtures/proc/modules
Lines: 89
nft_counter 16384 4 - Live 0xffffffffc0c77000
nft_chain_nat 16384 2 - Live 0xffffffffc0c72000
nft_compat 20480 8 - Live 0xffffffffc0c6c000
xt_tcpudp 20480 4 - Live 0xffffffffc0c66000
xt_nat 16384 4 - Live 0xffffffffc0c61000
xt_multiport 20480 0 - Live 0xffffffffc0c5b000
xt_mark 16384 0 - Live 0xffffffffc0c56000
xt_conntrack 16384 0 - Live 0xffffffffc0c42000
xt_comment 16384 0 - Live 0xffffffffc0c3d000
xt_addrtype 16384 0 - Live 0xffffffffc0c51000
xt_MASQUERADE 20480 0 - Live 0xffffffffc0c4b000
nf_tables 245760 19 nft_counter,nft_chain_nat,nft_compat, Live 0xffffffffc0c00000
nfnetlink 20480 2 nft_compat,nf_tables, Live 0xffffffffc0bfa000
ip6table_filter 16384 0 - Live 0xffffffffc0b8b000
iptable_filter 16384 0 - Live 0xffffffffc0bde000
ip6table_nat 16384 0 - Live 0xffffffffc0bd9000
iptable_nat 16384 0 - Live 0xffffffffc0bf5000
nf_nat 49152 5 nft_chain_nat,xt_nat,xt_MASQUERADE,ip6table_nat,iptable_nat, Live 0xffffffffc0be8000
nf_conntrack 172032 4 xt_nat,xt_conntrack,xt_MASQUERADE,nf_nat, Live 0xffffffffc0bae000
nf_defrag_ipv6 24576 1 nf_conntrack, Live 0xffffffffc0ba3000
nf_defrag_ipv4 16384 1 nf_conntrack, Live 0xffffffffc0b9e000
ip6_tables 32768 2 ip6table_filter,ip6table_nat, Live 0xffffffffc0b82000
veth 32768 0 - Live 0xffffffffc0b95000
bridge 307200 0 - Live 0xffffffffc0b36000
stp 16384 1 bridge, Live 0xffffffffc0b2f000
llc 16384 2 bridge,stp, Live 0xffffffffc0b26000
tap 28672 0 - Live 0xffffffffc0b1b000
binfmt_misc 24576 1 - Live 0xffffffffc0ad6000
overlay 151552 0 - Live 0xffffffffc0ab0000
isofs 53248 1 - Live 0xffffffffc09d0000
nls_iso8859_1 16384 1 - Live 0xffffffffc097f000
input_leds 16384 0 - Live 0xffffffffc099d000
serio_raw 20480 0 - Live 0xffffffffc098b000
virtio_input 20480 0 - Live 0xffffffffc0979000
dm_multipath 40960 0 - Live 0xffffffffc093f000
sch_fq_codel 20480 3 - Live 0xffffffffc0939000
scsi_dh_rdac 20480 0 - Live 0xffffffffc0930000
scsi_dh_emc 16384 0 - Live 0xffffffffc0928000
scsi_dh_alua 20480 0 - Live 0xffffffffc0917000
ipmi_devintf 20480 0 - Live 0xffffffffc091e000
ipmi_msghandler 122880 1 ipmi_devintf, Live 0xffffffffc08f8000
msr 16384 0 - Live 0xffffffffc08f0000
efi_pstore 16384 0 - Live 0xffffffffc08eb000
virtio_rng 16384 0 - Live 0xffffffffc0581000
ip_tables 32768 2 iptable_filter,iptable_nat, Live 0xffffffffc0743000
x_tables 53248 15 nft_compat,xt_tcpudp,xt_nat,xt_multiport,xt_mark,xt_conntrack,xt_comment,xt_addrtype,xt_MASQUERADE,ip6table_filter,iptable_filter,ip6table_nat,iptable_nat,ip6_tables,ip_tables, Live 0xffffffffc0735000
autofs4 49152 2 - Live 0xffffffffc0728000
btrfs 1552384 0 - Live 0xffffffffc0761000
blake2b_generic 20480 0 - Live 0xffffffffc06d3000
zstd_compress 229376 1 btrfs, Live 0xffffffffc06ef000
raid10 69632 0 - Live 0xffffffffc06dd000
raid456 163840 0 - Live 0xffffffffc06aa000
async_raid6_recov 24576 1 raid456, Live 0xffffffffc06a3000
async_memcpy 20480 2 raid456,async_raid6_recov, Live 0xffffffffc069d000
async_pq 24576 2 raid456,async_raid6_recov, Live 0xffffffffc0696000
async_xor 20480 3 raid456,async_raid6_recov,async_pq, Live 0xffffffffc0690000
async_tx 20480 5 raid456,async_raid6_recov,async_memcpy,async_pq,async_xor, Live 0xffffffffc068a000
xor 24576 2 btrfs,async_xor, Live 0xffffffffc0593000
raid6_pq 122880 4 btrfs,raid456,async_raid6_recov,async_pq, Live 0xffffffffc066b000
libcrc32c 16384 5 nf_tables,nf_nat,nf_conntrack,btrfs,raid456, Live 0xffffffffc0556000
raid1 49152 0 - Live 0xffffffffc0610000
raid0 24576 0 - Live 0xffffffffc0517000
multipath 20480 0 - Live 0xffffffffc0501000
linear 20480 0 - Live 0xffffffffc045b000
virtio_gpu 69632 0 - Live 0xffffffffc05a0000
virtio_dma_buf 16384 1 virtio_gpu, Live 0xffffffffc0536000
crct10dif_pclmul 16384 1 - Live 0xffffffffc050e000
drm_kms_helper 311296 3 virtio_gpu, Live 0xffffffffc061e000
crc32_pclmul 16384 0 - Live 0xffffffffc0527000
syscopyarea 16384 1 drm_kms_helper, Live 0xffffffffc0520000
sysfillrect 20480 1 drm_kms_helper, Live 0xffffffffc0508000
ghash_clmulni_intel 16384 0 - Live 0xffffffffc0456000
sysimgblt 16384 1 drm_kms_helper, Live 0xffffffffc04fc000
fb_sys_fops 16384 1 drm_kms_helper, Live 0xffffffffc0425000
cec 61440 1 drm_kms_helper, Live 0xffffffffc0751000
rc_core 65536 1 cec, Live 0xffffffffc0540000
aesni_intel 376832 0 - Live 0xffffffffc05b3000
crypto_simd 16384 1 aesni_intel, Live 0xffffffffc059b000
ahci 45056 1 - Live 0xffffffffc0587000
virtio_net 61440 0 - Live 0xffffffffc0571000
xhci_pci 24576 0 - Live 0xffffffffc0562000
net_failover 20480 1 virtio_net, Live 0xffffffffc055c000
cryptd 24576 2 ghash_clmulni_intel,crypto_simd, Live 0xffffffffc052c000
drm 622592 3 virtio_gpu,drm_kms_helper, Live 0xffffffffc0463000 (POE)
psmouse 176128 0 - Live 0xffffffffc042a000
libahci 45056 1 ahci, Live 0xffffffffc0419000
virtio_blk 20480 2 - Live 0xffffffffc040f000
xhci_pci_renesas 20480 1 xhci_pci, Live 0xffffffffc0407000
failover 16384 1 net_failover, Live 0xffffffffc03ff000 (P)
Mode: 644
# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Directory: fixtures/proc/net
Mode: 755
# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Expand Down