Resolve relative paths

maybe/__init__.py

@@ -8,9 +8,12 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
+from os import readlink
+from os.path import join
 from collections import namedtuple
 
 from blessings import Terminal
+from ptrace.syscall.posix_arg import AT_FDCWD
 
 
 SyscallFilter = namedtuple("SyscallFilter", ["syscall", "format", "substitute"])
@@ -38,3 +41,15 @@ def initialize_terminal(style_output):
  "no": None,
  "auto": False,
  }[style_output])
+
+
+# Implements the path resolution logic of the "*at" syscalls
+def get_full_path(pid, path, directory_descriptor=AT_FDCWD):
+ if directory_descriptor == AT_FDCWD:
+ # Current working directory
+ directory = readlink("/proc/%d/cwd" % pid)
+ else:
+ # Directory referred to by directory_descriptor
+ directory = readlink("/proc/%d/fd/%d" % (pid, directory_descriptor))
+ # Note that join will discard directory if path is absolute, as desired
+ return join(directory, path)

maybe/filters/change_owner.py

@@ -10,9 +10,8 @@
 
 from pwd import getpwuid
 from grp import getgrgid
-from os.path import abspath
 
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 from maybe.filters.create_write_file import get_file_descriptor_path
 
 
@@ -26,24 +25,24 @@ def format_change_owner(path, owner, group):
  else:
  label = "change owner"
  owner = getpwuid(owner)[0] + ":" + getgrgid(group)[0]
- return "%s of %s to %s" % (T.yellow(label), T.underline(abspath(path)), T.bold(owner))
+ return "%s of %s to %s" % (T.yellow(label), T.underline(path), T.bold(owner))
 
 
 SYSCALL_FILTERS["change_owner"] = [
  SyscallFilter(
  syscall="chown",
- format=lambda pid, args: format_change_owner(args[0], args[1], args[2]),
+ format=lambda pid, args: format_change_owner(get_full_path(pid, args[0]), args[1], args[2]),
  ),
  SyscallFilter(
  syscall="fchown",
  format=lambda pid, args: format_change_owner(get_file_descriptor_path(args[0]), args[1], args[2]),
  ),
  SyscallFilter(
  syscall="lchown",
- format=lambda pid, args: format_change_owner(args[0], args[1], args[2]),
+ format=lambda pid, args: format_change_owner(get_full_path(pid, args[0]), args[1], args[2]),
  ),
  SyscallFilter(
  syscall="fchownat",
- format=lambda pid, args: format_change_owner(args[1], args[2], args[3]),
+ format=lambda pid, args: format_change_owner(get_full_path(pid, args[1], args[0]), args[2], args[3]),
  ),
 ]

maybe/filters/change_permissions.py

@@ -8,9 +8,7 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
-from os.path import abspath
-
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 from maybe.filters.create_write_file import get_file_descriptor_path
 
 
@@ -24,21 +22,21 @@ def format_permissions(permissions):
 
 
 def format_change_permissions(path, permissions):
- return "%s of %s to %s" % (T.yellow("change permissions"), T.underline(abspath(path)),
+ return "%s of %s to %s" % (T.yellow("change permissions"), T.underline(path),
  T.bold(format_permissions(permissions)))
 
 
 SYSCALL_FILTERS["change_permissions"] = [
  SyscallFilter(
  syscall="chmod",
- format=lambda pid, args: format_change_permissions(args[0], args[1]),
+ format=lambda pid, args: format_change_permissions(get_full_path(pid, args[0]), args[1]),
  ),
  SyscallFilter(
  syscall="fchmod",
  format=lambda pid, args: format_change_permissions(get_file_descriptor_path(args[0]), args[1]),
  ),
  SyscallFilter(
  syscall="fchmodat",
- format=lambda pid, args: format_change_permissions(args[1], args[2]),
+ format=lambda pid, args: format_change_permissions(get_full_path(pid, args[1], args[0]), args[2]),
  ),
 ]

maybe/filters/create_directory.py

@@ -8,22 +8,20 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
-from os.path import abspath
-
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 
 
 def format_create_directory(path):
- return "%s %s" % (T.cyan("create directory"), T.underline(abspath(path)))
+ return "%s %s" % (T.cyan("create directory"), T.underline(path))
 
 
 SYSCALL_FILTERS["create_directory"] = [
  SyscallFilter(
  syscall="mkdir",
- format=lambda pid, args: format_create_directory(args[0]),
+ format=lambda pid, args: format_create_directory(get_full_path(pid, args[0])),
  ),
  SyscallFilter(
  syscall="mkdirat",
- format=lambda pid, args: format_create_directory(args[1]),
+ format=lambda pid, args: format_create_directory(get_full_path(pid, args[1], args[0])),
  ),
 ]

maybe/filters/create_link.py

@@ -8,31 +8,33 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
-from os.path import abspath
-
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 
 
 def format_create_link(path_source, path_target, symbolic):
  label = "create symbolic link" if symbolic else "create hard link"
- return "%s from %s to %s" % (T.cyan(label), T.underline(abspath(path_source)), T.underline(abspath(path_target)))
+ return "%s from %s to %s" % (T.cyan(label), T.underline(path_source), T.underline(path_target))
 
 
 SYSCALL_FILTERS["create_link"] = [
  SyscallFilter(
  syscall="link",
- format=lambda pid, args: format_create_link(args[1], args[0], False),
+ format=lambda pid, args: format_create_link(get_full_path(pid, args[1]),
+ get_full_path(pid, args[0]), False),
  ),
  SyscallFilter(
  syscall="linkat",
- format=lambda pid, args: format_create_link(args[3], args[1], False),
+ format=lambda pid, args: format_create_link(get_full_path(pid, args[3], args[2]),
+ get_full_path(pid, args[1], args[0]), False),
  ),
  SyscallFilter(
  syscall="symlink",
- format=lambda pid, args: format_create_link(args[1], args[0], True),
+ format=lambda pid, args: format_create_link(get_full_path(pid, args[1]),
+ get_full_path(pid, args[0]), True),
  ),
  SyscallFilter(
  syscall="symlinkat",
- format=lambda pid, args: format_create_link(args[2], args[0], True),
+ format=lambda pid, args: format_create_link(get_full_path(pid, args[2], args[1]),
+ get_full_path(pid, args[0]), True),
  ),
 ]

maybe/filters/create_write_file.py

@@ -8,11 +8,11 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
-from os.path import abspath, exists
+from os.path import exists
 from os import O_WRONLY, O_RDWR, O_APPEND, O_CREAT, O_TRUNC
 from stat import S_IFCHR, S_IFBLK, S_IFIFO, S_IFSOCK
 
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 
 
 # Start with a large number to avoid collisions with other FDs
@@ -36,7 +36,6 @@ def get_file_descriptor_path(file_descriptor):
 
 
 def format_open(path, flags):
- path = abspath(path)
  if path in allowed_files:
  return None
  elif (flags & O_CREAT) and not exists(path):
@@ -48,7 +47,6 @@ def format_open(path, flags):
 
 
 def substitute_open(path, flags):
- path = abspath(path)
  if path in allowed_files:
  return None
  elif (flags & O_WRONLY) or (flags & O_RDWR) or (flags & O_APPEND) or (format_open(path, flags) is not None):
@@ -61,7 +59,6 @@ def substitute_open(path, flags):
 
 
 def format_mknod(path, type):
- path = abspath(path)
  if exists(path):
  return None
  elif (type & S_IFCHR):
@@ -108,28 +105,28 @@ def substitute_dup(file_descriptor_old, file_descriptor_new=None):
 SYSCALL_FILTERS["create_write_file"] = [
  SyscallFilter(
  syscall="open",
- format=lambda pid, args: format_open(args[0], args[1]),
- substitute=lambda pid, args: substitute_open(args[0], args[1]),
+ format=lambda pid, args: format_open(get_full_path(pid, args[0]), args[1]),
+ substitute=lambda pid, args: substitute_open(get_full_path(pid, args[0]), args[1]),
  ),
  SyscallFilter(
  syscall="creat",
- format=lambda pid, args: format_open(args[0], O_CREAT | O_WRONLY | O_TRUNC),
- substitute=lambda pid, args: substitute_open(args[0], O_CREAT | O_WRONLY | O_TRUNC),
+ format=lambda pid, args: format_open(get_full_path(pid, args[0]), O_CREAT | O_WRONLY | O_TRUNC),
+ substitute=lambda pid, args: substitute_open(get_full_path(pid, args[0]), O_CREAT | O_WRONLY | O_TRUNC),
  ),
  SyscallFilter(
  syscall="openat",
- format=lambda pid, args: format_open(args[1], args[2]),
- substitute=lambda pid, args: substitute_open(args[1], args[2]),
+ format=lambda pid, args: format_open(get_full_path(pid, args[1], args[0]), args[2]),
+ substitute=lambda pid, args: substitute_open(get_full_path(pid, args[1], args[0]), args[2]),
  ),
  SyscallFilter(
  syscall="mknod",
- format=lambda pid, args: format_mknod(args[0], args[1]),
- substitute=lambda pid, args: substitute_mknod(args[0], args[1]),
+ format=lambda pid, args: format_mknod(get_full_path(pid, args[0]), args[1]),
+ substitute=lambda pid, args: substitute_mknod(get_full_path(pid, args[0]), args[1]),
  ),
  SyscallFilter(
  syscall="mknodat",
- format=lambda pid, args: format_mknod(args[1], args[2]),
- substitute=lambda pid, args: substitute_mknod(args[1], args[2]),
+ format=lambda pid, args: format_mknod(get_full_path(pid, args[1], args[0]), args[2]),
+ substitute=lambda pid, args: substitute_mknod(get_full_path(pid, args[1], args[0]), args[2]),
  ),
  SyscallFilter(
  syscall="write",

maybe/filters/delete.py

@@ -8,26 +8,24 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
-from os.path import abspath
-
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 
 
 def format_delete(path):
- return "%s %s" % (T.red("delete"), T.underline(abspath(path)))
+ return "%s %s" % (T.red("delete"), T.underline(path))
 
 
 SYSCALL_FILTERS["delete"] = [
  SyscallFilter(
  syscall="unlink",
- format=lambda pid, args: format_delete(args[0]),
+ format=lambda pid, args: format_delete(get_full_path(pid, args[0])),
  ),
  SyscallFilter(
  syscall="unlinkat",
- format=lambda pid, args: format_delete(args[1]),
+ format=lambda pid, args: format_delete(get_full_path(pid, args[1], args[0])),
  ),
  SyscallFilter(
  syscall="rmdir",
- format=lambda pid, args: format_delete(args[0]),
+ format=lambda pid, args: format_delete(get_full_path(pid, args[0])),
  ),
 ]

maybe/filters/move.py

@@ -8,14 +8,12 @@
 # (https://gnu.org/licenses/gpl.html)
 
 
-from os.path import abspath, dirname, basename
+from os.path import dirname, basename
 
-from maybe import SyscallFilter, SYSCALL_FILTERS, T
+from maybe import SyscallFilter, SYSCALL_FILTERS, T, get_full_path
 
 
 def format_move(path_old, path_new):
- path_old = abspath(path_old)
- path_new = abspath(path_new)
  if dirname(path_old) == dirname(path_new):
  label = "rename"
  path_new = basename(path_new)
@@ -27,14 +25,17 @@ def format_move(path_old, path_new):
 SYSCALL_FILTERS["move"] = [
  SyscallFilter(
  syscall="rename",
- format=lambda pid, args: format_move(args[0], args[1]),
+ format=lambda pid, args: format_move(get_full_path(pid, args[0]),
+ get_full_path(pid, args[1])),
  ),
  SyscallFilter(
  syscall="renameat",
- format=lambda pid, args: format_move(args[1], args[3]),
+ format=lambda pid, args: format_move(get_full_path(pid, args[1], args[0]),
+ get_full_path(pid, args[3], args[2])),
  ),
  SyscallFilter(
  syscall="renameat2",
- format=lambda pid, args: format_move(args[1], args[3]),
+ format=lambda pid, args: format_move(get_full_path(pid, args[1], args[0]),
+ get_full_path(pid, args[3], args[2])),
  ),
 ]