mirror of
https://github.com/opencontainers/runc.git
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Kir Kolyshkin
6cd91f665e
The Config type is quite big (currently 554 bytes on a 64 bit Linux) and using non-pointer receivers in its methods results in copying which is totally unnecessary. Change the methods to use pointer receivers. Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
98 lines
3.2 KiB
Go
98 lines
3.2 KiB
Go
package configs
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import (
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"errors"
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"fmt"
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"math"
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)
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var (
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errNoUIDMap = errors.New("user namespaces enabled, but no uid mappings found")
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errNoGIDMap = errors.New("user namespaces enabled, but no gid mappings found")
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)
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// Please check https://man7.org/linux/man-pages/man2/personality.2.html for const details.
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// https://raw.githubusercontent.com/torvalds/linux/master/include/uapi/linux/personality.h
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const (
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PerLinux = 0x0000
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PerLinux32 = 0x0008
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)
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type LinuxPersonality struct {
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// Domain for the personality
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// can only contain values "LINUX" and "LINUX32"
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Domain int `json:"domain"`
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}
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// HostUID gets the translated uid for the process on host which could be
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// different when user namespaces are enabled.
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func (c *Config) HostUID(containerID int) (int, error) {
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if c.Namespaces.Contains(NEWUSER) {
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if len(c.UIDMappings) == 0 {
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return -1, errNoUIDMap
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}
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id, found := c.hostIDFromMapping(int64(containerID), c.UIDMappings)
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if !found {
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return -1, fmt.Errorf("user namespaces enabled, but no mapping found for uid %d", containerID)
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}
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// If we are a 32-bit binary running on a 64-bit system, it's possible
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// the mapped user is too large to store in an int, which means we
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// cannot do the mapping. We can't just return an int64, because
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// os.Setuid() takes an int.
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if id > math.MaxInt {
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return -1, fmt.Errorf("mapping for uid %d (host id %d) is larger than native integer size (%d)", containerID, id, math.MaxInt)
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}
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return int(id), nil
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}
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// Return unchanged id.
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return containerID, nil
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}
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// HostRootUID gets the root uid for the process on host which could be non-zero
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// when user namespaces are enabled.
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func (c *Config) HostRootUID() (int, error) {
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return c.HostUID(0)
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}
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// HostGID gets the translated gid for the process on host which could be
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// different when user namespaces are enabled.
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func (c *Config) HostGID(containerID int) (int, error) {
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if c.Namespaces.Contains(NEWUSER) {
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if len(c.GIDMappings) == 0 {
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return -1, errNoGIDMap
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}
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id, found := c.hostIDFromMapping(int64(containerID), c.GIDMappings)
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if !found {
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return -1, fmt.Errorf("user namespaces enabled, but no mapping found for gid %d", containerID)
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}
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// If we are a 32-bit binary running on a 64-bit system, it's possible
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// the mapped user is too large to store in an int, which means we
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// cannot do the mapping. We can't just return an int64, because
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// os.Setgid() takes an int.
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if id > math.MaxInt {
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return -1, fmt.Errorf("mapping for gid %d (host id %d) is larger than native integer size (%d)", containerID, id, math.MaxInt)
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}
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return int(id), nil
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}
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// Return unchanged id.
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return containerID, nil
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}
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// HostRootGID gets the root gid for the process on host which could be non-zero
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// when user namespaces are enabled.
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func (c *Config) HostRootGID() (int, error) {
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return c.HostGID(0)
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}
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// Utility function that gets a host ID for a container ID from user namespace map
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// if that ID is present in the map.
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func (c *Config) hostIDFromMapping(containerID int64, uMap []IDMap) (int64, bool) {
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for _, m := range uMap {
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if (containerID >= m.ContainerID) && (containerID <= (m.ContainerID + m.Size - 1)) {
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hostID := m.HostID + (containerID - m.ContainerID)
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return hostID, true
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}
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}
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return -1, false
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}
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