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