[oe-commits] [bitbake] 05/05: siggen: Add checksum recalculation/checking code

[git at git.openembedded.org]

rpurdie pushed a commit to branch master-next
in repository bitbake.

commit 0f50a18d7a0ea0d68edd8e5217e29111f4b1ea0b
Author: Richard Purdie <richard.purdie at linuxfoundation.org>
AuthorDate: Sat Apr 2 17:11:26 2016 +0100

    siggen: Add checksum recalculation/checking code
    
    In theory all the information to recalcuate the task signatures was written
    into the siginfo/sigdata files. In reality, some of the information was
    written into the filename.
    
    Firstly this patch duplicates that info into the file itself just for easy
    of use since its small.
    
    Secondly, we abstract out the existing "calculate the checksum" code for
    the taskhash, and add a function to calculate the bashhash based on the
    informaiton within the file.
    
    Finally, we call these functions when we're writing out the data to check
    that the data we're writing is consistent. I've found a couple of places
    it wasn't and its good to know about these in advance, rather than having
    a siginfo/sigdata file which a given hash in its filename but a contents
    which give a different result.
    
    This should all combine to avoid a certain class of checksum bugs making
    it into world, and identifying problems in advance.
    
    Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
 lib/bb/siggen.py | 60 +++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 49 insertions(+), 11 deletions(-)

diff --git a/lib/bb/siggen.py b/lib/bb/siggen.py
index d8ba1d4..2f0fb71 100644
--- a/lib/bb/siggen.py
+++ b/lib/bb/siggen.py
@@ -248,6 +248,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
         bb.utils.mkdirhier(os.path.dirname(sigfile))
 
         data = {}
+        data['task'] = task
         data['basewhitelist'] = self.basewhitelist
         data['taskwhitelist'] = self.taskwhitelist
         data['taskdeps'] = self.taskdeps[fn][task]
@@ -267,6 +268,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
             data['runtaskhashes'] = {}
             for dep in data['runtaskdeps']:
                 data['runtaskhashes'][dep] = self.taskhash[dep]
+            data['taskhash'] = self.taskhash[k]
 
         taint = self.read_taint(fn, task, stampbase)
         if taint:
@@ -290,6 +292,15 @@ class SignatureGeneratorBasic(SignatureGenerator):
                 pass
             raise err
 
+        computed_basehash = calc_basehash(data)
+        if computed_basehash != self.basehash[k]:
+            bb.error("Basehash mismatch %s verses %s for %s" % (computed_basehash, self.basehash[k], k))
+        if k in self.taskhash:
+            computed_taskhash = calc_taskhash(data)
+            if computed_taskhash != self.taskhash[k]:
+                bb.error("Taskhash mismatch %s verses %s for %s" % (computed_taskhash, self.taskhash[k], k))
+
+
     def dump_sigs(self, dataCache, options):
         for fn in self.taskdeps:
             for task in self.taskdeps[fn]:
@@ -506,6 +517,37 @@ def compare_sigfiles(a, b, recursecb = None):
     return output
 
 
+def calc_basehash(sigdata):
+    task = sigdata['task']
+    basedata = sigdata['varvals'][task]
+
+    if basedata is None:
+        basedata = ''
+
+    alldeps = sigdata['taskdeps']
+    for dep in alldeps:
+        basedata = basedata + dep
+        val = sigdata['varvals'][dep]
+        if val is not None:
+            basedata = basedata + str(val)
+
+    return hashlib.md5(basedata).hexdigest()
+
+def calc_taskhash(sigdata):
+    data = sigdata['basehash']
+
+    for dep in sigdata['runtaskdeps']:
+        data = data + sigdata['runtaskhashes'][dep]
+
+    for c in sigdata['file_checksum_values']:
+        data = data + c[1]
+
+    if 'taint' in sigdata:
+        data = data + sigdata['taint']
+
+    return hashlib.md5(data).hexdigest()
+
+
 def dump_sigfile(a):
     output = []
 
@@ -539,17 +581,13 @@ def dump_sigfile(a):
     if 'taint' in a_data:
         output.append("Tainted (by forced/invalidated task): %s" % a_data['taint'])
 
-    data = a_data['basehash']
-    for dep in a_data['runtaskdeps']:
-        data = data + a_data['runtaskhashes'][dep]
-
-    for c in a_data['file_checksum_values']:
-        data = data + c[1]
-
-    if 'taint' in a_data:
-        data = data + a_data['taint']
+    if 'task' in a_data:
+        computed_basehash = calc_basehash(a_data)
+        output.append("Computed base hash is %s and from file %s" % (computed_basehash, a_data['basehash']))
+    else:
+        output.append("Unable to compute base hash")
 
-    h = hashlib.md5(data).hexdigest()
-    output.append("Computed Hash is %s" % h)
+    computed_taskhash = calc_taskhash(a_data)
+    output.append("Computed task hash is %s" % computed_taskhash)
 
     return output

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