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package opts
import (
"sort"
"strings"
)
const (
// AllCapabilities is a special value to add or drop all capabilities
AllCapabilities = "ALL"
// ResetCapabilities is a special value to reset capabilities when updating.
// This value should only be used when updating, not used on "create".
ResetCapabilities = "RESET"
)
// NormalizeCapability normalizes a capability by upper-casing, trimming white space
// and adding a CAP_ prefix (if not yet present). This function also accepts the
// "ALL" magic-value, as used by CapAdd/CapDrop.
//
// This function only handles rudimentary formatting; no validation is performed,
// as the list of available capabilities can be updated over time, thus should be
// handled by the daemon.
func NormalizeCapability(cap string) string {
cap = strings.ToUpper(strings.TrimSpace(cap))
if cap == AllCapabilities || cap == ResetCapabilities {
return cap
}
if !strings.HasPrefix(cap, "CAP_") {
cap = "CAP_" + cap
}
return cap
}
// CapabilitiesMap normalizes the given capabilities and converts them to a map.
func CapabilitiesMap(caps []string) map[string]bool {
normalized := make(map[string]bool)
for _, c := range caps {
normalized[NormalizeCapability(c)] = true
}
return normalized
}
// EffectiveCapAddCapDrop normalizes and sorts capabilities to "add" and "drop",
// and returns the effective capabilities to include in both.
//
// "CapAdd" takes precedence over "CapDrop", so capabilities included in both
// lists are removed from the list of capabilities to drop. The special "ALL"
// capability is also taken into account.
//
// Note that the special "RESET" value is only used when updating an existing
// service, and will be ignored.
//
// Duplicates are removed, and the resulting lists are sorted.
func EffectiveCapAddCapDrop(add, drop []string) (capAdd, capDrop []string) {
var (
addCaps = CapabilitiesMap(add)
dropCaps = CapabilitiesMap(drop)
)
if addCaps[AllCapabilities] {
// Special case: "ALL capabilities" trumps any other capability added.
addCaps = map[string]bool{AllCapabilities: true}
}
if dropCaps[AllCapabilities] {
// Special case: "ALL capabilities" trumps any other capability added.
dropCaps = map[string]bool{AllCapabilities: true}
}
for c := range dropCaps {
if addCaps[c] {
// Adding a capability takes precedence, so skip dropping
continue
}
if c != ResetCapabilities {
capDrop = append(capDrop, c)
}
}
for c := range addCaps {
if c != ResetCapabilities {
capAdd = append(capAdd, c)
}
}
sort.Strings(capAdd)
sort.Strings(capDrop)
return capAdd, capDrop
}
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