From: eliben <devnull@localhost>
Date: Thu, 8 Sep 2011 11:49:30 +0000 (+0300)
Subject: * Added handling of segments
X-Git-Tag: v0.10~137
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a6416fd4d6c24e29a4b781360a5f973aa4bfd363;p=pyelftools.git

* Added handling of segments
* Added iteration API for sections
---

diff --git a/elftools/elf/elffile.py b/elftools/elf/elffile.py
index 11d3704..01be519 100644
--- a/elftools/elf/elffile.py
+++ b/elftools/elf/elffile.py
@@ -13,6 +13,7 @@ from ..exceptions import ELFError, ELFParseError
 from ..construct import ConstructError, CString
 from .structs import ELFStructs
 from .sections import Section
+from .segments import Segment
 
 
 class ELFFile(object):
@@ -37,7 +38,7 @@ class ELFFile(object):
         self._stringtable = self._get_stringtable()
     
     def num_sections(self):
-        """ Get the number of sections in the file
+        """ Number of sections in the file
         """
         return self['e_shnum']
     
@@ -48,6 +49,29 @@ class ELFFile(object):
         name = self._get_section_name(section_header)
         return Section(section_header, name, self.stream)
     
+    def iter_sections(self):
+        """ Yield all the sections in the file
+        """
+        for i in range(self.num_sections()):
+            yield self.get_section(i)
+    
+    def num_segments(self):
+        """ Number of segments in the file
+        """
+        return self['e_phnum']
+    
+    def get_segment(self, n):
+        """ Get the segment at index #n from the file (Segment object)
+        """
+        segment_header = self._get_segment_header(n)
+        return Segment(segment_header, self.stream)
+    
+    def iter_segments(self):
+        """ Yield all the segments in the file
+        """
+        for i in range(self.num_segments()):
+            yield self.get_segment(i)
+    
     #-------------------------------- PRIVATE --------------------------------#
     
     def __getitem__(self, name):
@@ -87,12 +111,23 @@ class ELFFile(object):
         """
         return self['e_shoff'] + n * self['e_shentsize']
     
+    def _segment_offset(self, n):
+        """ Compute the offset of segment #n in the file
+        """
+        return self['e_phoff'] + n * self['e_phentsize']
+    
     def _get_section_header(self, n):
         """ Find the header of section #n, parse it and return the struct 
         """
         self.stream.seek(self._section_offset(n))
         return self._struct_parse(self.structs.Elf_Shdr)
     
+    def _get_segment_header(self, n):
+        """ Find the header of segment #n, parse it and return the struct
+        """
+        self.stream.seek(self._segment_offset(n))
+        return self._struct_parse(self.structs.Elf_Phdr)
+    
     def _get_section_name(self, section_header):
         """ Given a section header, find this section's name in the file's
             string table, and return it as a normal Python string.
diff --git a/elftools/elf/enums.py b/elftools/elf/enums.py
index 1217d74..cdaf316 100644
--- a/elftools/elf/enums.py
+++ b/elftools/elf/enums.py
@@ -89,6 +89,7 @@ ENUM_SH_TYPE = dict(
 )
 
 # p_type in the program header
+# some values scavenged from the ELF headers in binutils-2.21
 ENUM_P_TYPE = dict(
     PT_NULL=0,
     PT_LOAD=1,
@@ -99,5 +100,8 @@ ENUM_P_TYPE = dict(
     PT_PHDR=6,
     PT_LOPROC=0x70000000,
     PT_HIPROC=0x7fffffff,
+    PT_GNU_EH_FRAME=0x6474e550,
+    PT_GNU_STACK=0x6474e551,
+    PT_GNU_RELRO=0x6474e552,
 )
 
diff --git a/elftools/elf/segments.py b/elftools/elf/segments.py
new file mode 100644
index 0000000..02a81ed
--- /dev/null
+++ b/elftools/elf/segments.py
@@ -0,0 +1,25 @@
+#-------------------------------------------------------------------------------
+# elftools: elf/segments.py
+#
+# ELF segments
+#
+# Eli Bendersky (eliben@gmail.com)
+# This code is in the public domain
+#-------------------------------------------------------------------------------
+
+class Segment(object):
+    def __init__(self, header, stream):
+        self.header = header
+        self.stream = stream
+    
+    def data(self):
+        """ The segment data from the file.
+        """
+        self.stream.seek(self['p_offset'])
+        return self.stream.read(self['p_filesz'])
+
+    def __getitem__(self, name):
+        """ Implement dict-like access to header entries
+        """
+        return self.header[name]
+
diff --git a/z.py b/z.py
index c74a4ff..9f208d3 100644
--- a/z.py
+++ b/z.py
@@ -9,12 +9,18 @@ stream = open('binfiles/z.elf', 'rb')
 
 efile = ELFFile(stream)
 
-print 'num', efile.num_sections()
-sec = efile.get_section(39)
+for sec in efile.iter_sections():
+    print sec.name
+
+for seg in efile.iter_segments():
+    print seg['p_type'], seg['p_offset']
+
+#~ print 'num', efile.num_sections()
+#~ sec = efile.get_section(39)
 #~ print sec.header
-print sec.name
-print sec['sh_type']
-print map(ord, sec.data())
+#~ print sec.name
+#~ print sec['sh_type']
+#~ print map(ord, sec.data())
 
 #~ print sec.stream
 #~ print map(ord, efile._stringtable)