Refactor resolving of links in ldcache

Signed-off-by: Evan Lezar <elezar@nvidia.com>
This commit is contained in:
Evan Lezar 2022-12-13 14:28:49 +01:00
parent 80672d33af
commit f350f0c0bb

View File

@ -22,6 +22,7 @@ import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"os"
"path/filepath"
"syscall"
@ -205,18 +206,14 @@ func (c *ldcache) List() ([]string, []string) {
continue
}
value := c.libs[e.Value:]
n := bytes.IndexByte(value, 0)
if n < 0 {
name := bytesToString(value)
if name == "" {
continue
}
name := filepath.Join(c.root, strn(value, n))
c.logger.Debugf("checking %v", string(name))
path, err := filepath.EvalSymlinks(name)
path, err := c.resolve(name)
if err != nil {
c.logger.Debugf("could not resolve symlink for %v", name)
c.logger.Debugf("Could not resolve entry: %v", err)
continue
}
if processed[path] {
@ -233,10 +230,9 @@ func (c *ldcache) List() ([]string, []string) {
// The 32-bit and 64-bit libraries matching the prefixes are returned.
func (c *ldcache) Lookup(libs ...string) (paths32, paths64 []string) {
c.logger.Debugf("Looking up %v in cache", libs)
type void struct{}
var paths *[]string
set := make(map[string]void)
processed := make(map[string]bool)
prefix := make([][]byte, len(libs))
for i := range libs {
@ -264,25 +260,22 @@ func (c *ldcache) Lookup(libs ...string) (paths32, paths64 []string) {
lib := c.libs[e.Key:]
value := c.libs[e.Value:]
name := bytesToString(value)
if name == "" {
continue
}
for _, p := range prefix {
if bytes.HasPrefix(lib, p) {
n := bytes.IndexByte(value, 0)
if n < 0 {
break
}
name := filepath.Join(c.root, strn(value, n))
c.logger.Debugf("checking %v", string(name))
path, err := filepath.EvalSymlinks(name)
path, err := c.resolve(name)
if err != nil {
c.logger.Debugf("could not resolve symlink for %v", name)
c.logger.Debugf("Could not resolve entry: %v", err)
break
}
if _, ok := set[path]; ok {
if processed[path] {
break
}
set[path] = void{}
processed[path] = true
*paths = append(*paths, path)
break
}
@ -290,3 +283,30 @@ func (c *ldcache) Lookup(libs ...string) (paths32, paths64 []string) {
}
return
}
// resolve resolves the specified ldcache entry based on the value being processed.
// The input is the name of the entry in the cache.
func (c *ldcache) resolve(target string) (string, error) {
name := filepath.Join(c.root, target)
c.logger.Debugf("checking %v", name)
link, err := filepath.EvalSymlinks(name)
if err != nil {
return "", fmt.Errorf("failed to resolve symlink: %v", err)
}
c.logger.Debugf("Resolved link: '%v' => '%v'", name, link)
return link, nil
}
// bytesToString converts a byte slice to a string.
// This assumes that the byte slice is null-terminated
func bytesToString(value []byte) string {
n := bytes.IndexByte(value, 0)
if n < 0 {
return ""
}
return strn(value, n)
}