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mountinfo: GetMountsFromReader() remove redundant switch, fix dropped "optional" fields #81

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Merged
merged 3 commits into from
Aug 23, 2021
Merged

mountinfo: GetMountsFromReader() remove redundant switch, fix dropped "optional" fields #81

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7682d59
mountinfo: TestParseMountinfoExtraCases: use sub-tests
thaJeztah Aug 14, 2021
f6fd431
mountinfo: TestParseMountinfoExtraCases: add check for Optional field
thaJeztah Aug 14, 2021
df5b314
mountinfo: GetMountsFromReader() remove redundant switch, fix dropped…
thaJeztah Aug 14, 2021
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11 changes: 2 additions & 9 deletions mountinfo/mountinfo_linux.go
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Original file line number Diff line number Diff line change
Expand Up @@ -105,16 +105,9 @@ func GetMountsFromReader(r io.Reader, filter FilterFunc) ([]*Info, error) {
p.Options = fields[5]

// zero or more optional fields
switch {
case sepIdx == 6:
// zero, do nothing
case sepIdx == 7:
p.Optional = fields[6]
default:
p.Optional = strings.Join(fields[6:sepIdx-1], " ")
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Looks like there's an off-by-one bug here; removing this switch caused it to panic;

--- FAIL: TestMountedBy (0.01s)
panic: runtime error: slice bounds out of range [6:5] [recovered]
	panic: runtime error: slice bounds out of range [6:5]
  • we return an error if sepIdx == 5 (earlier check)
  • for sepIdx == 6 we skipped (in this switch)
  • for 7, we take field 6 (equivalent to fields[6:7], or fields[6:sepIdx])
  • for the "default" (else), we use fields[6:sepIdx-1], which for (e.g.) sepIndex=8 would do the same as sepIdx=7, so we'd drop one value

}
p.Optional = strings.Join(fields[6:sepIdx], " ")

// Run the filter after parsing all of the fields.
// Run the filter after parsing all fields.
var skip, stop bool
if filter != nil {
skip, stop = filter(p)
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64 changes: 35 additions & 29 deletions mountinfo/mountinfo_linux_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -676,13 +676,13 @@ func TestParseMountinfoExtraCases(t *testing.T) {
name: "one optional field",
entry: `251 15 0:3573 / /mnt/point rw,relatime shared:123 - aufs none rw`,
valid: true,
exp: &Info{Mountpoint: "/mnt/point", FSType: "aufs", Source: "none", Optional: "shared:123 extra:tag what:ever"},
exp: &Info{Mountpoint: "/mnt/point", FSType: "aufs", Source: "none", Optional: "shared:123"},
},
{
name: "extra optional fields", // which we carefully gather
entry: `251 15 0:3573 / /mnt/point rw,relatime shared:123 extra:tag what:ever key:value - aufs none rw`,
valid: true,
exp: &Info{Mountpoint: "/mnt/point", FSType: "aufs", Source: "none", Optional: "shared:123 extra:tag what:ever"},
exp: &Info{Mountpoint: "/mnt/point", FSType: "aufs", Source: "none", Optional: "shared:123 extra:tag what:ever key:value"},
},
{
name: "empty source field (kernel < 5.1 bug)",
Expand All @@ -693,34 +693,40 @@ func TestParseMountinfoExtraCases(t *testing.T) {
}

for _, tc := range testcases {
r := bytes.NewBufferString(tc.entry)
info, err := GetMountsFromReader(r, nil)
if !tc.valid {
if err == nil {
t.Errorf("case %q: expected error, got nil", tc.name)
tc := tc
t.Run(tc.name, func(t *testing.T) {
r := bytes.NewBufferString(tc.entry)
info, err := GetMountsFromReader(r, nil)
if !tc.valid {
if err == nil {
t.Errorf("expected error, got nil")
}
return
}
continue
}
if err != nil {
t.Errorf("case %q: expected no error, got %v", tc.name, err)
continue
}
if len(info) != 1 {
t.Errorf("case %q: expected 1 result, got %d", tc.name, len(info))
}
if tc.exp == nil {
continue
}
i := info[0]
if tc.exp.Mountpoint != "" && tc.exp.Mountpoint != i.Mountpoint {
t.Errorf("case %q: expected mp %s, got %s", tc.name, tc.exp.Mountpoint, i.Mountpoint)
}
if tc.exp.FSType != "" && tc.exp.FSType != i.FSType {
t.Errorf("case %q: expected fs %s, got %s", tc.name, tc.exp.FSType, i.FSType)
}
if tc.exp.Source != "" && tc.exp.Source != i.Source {
t.Errorf("case %q: expected src %s, got %s", tc.name, tc.exp.Source, i.Source)
}
if err != nil {
t.Errorf("expected no error, got %v", err)
return
}
if len(info) != 1 {
t.Errorf("expected 1 result, got %d", len(info))
}
if tc.exp == nil {
return
}
i := info[0]
if tc.exp.Mountpoint != "" && tc.exp.Mountpoint != i.Mountpoint {
t.Errorf("expected mp %s, got %s", tc.exp.Mountpoint, i.Mountpoint)
}
if tc.exp.FSType != "" && tc.exp.FSType != i.FSType {
t.Errorf("expected fs %s, got %s", tc.exp.FSType, i.FSType)
}
if tc.exp.Source != "" && tc.exp.Source != i.Source {
t.Errorf("expected src %s, got %s", tc.exp.Source, i.Source)
}
if tc.exp.Optional != "" && tc.exp.Optional != i.Optional {
t.Errorf("expected optional %s, got %s", tc.exp.Optional, i.Optional)
}
})
}
}

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