Hi -
Thanks for the review!
> On my machine memcheck reports leaks due to target_cachehdr_path
> missing a free. [...]
Sorry! I must have sent an immediately prior version of the patch;
the following one has the missing free().
> [...]
> There is some stray white space at the end of this line and elsewhere.
Hehehe, okay, nuked that.
> [...]
> It doesn't have to be done in this patch but we could add a read_retry
> function to elfutils lib/system.h to handle reading all bytes. There
> are some read calls in debuginfod.cxx where read_retry could also be used.
Just switched to using pread_retry() already there, and pwrite_retry()
for the corresponding other case.
v2 patch:
PR31862: debuginfod: client to cache x-debuginfod-* headers
This feature allows the extra http headers from debuginfod to be saved
into the client cache, and also thus replayed to clients. This way
they can perform IMA verification again, if they like, or a federating
caching intermediate debuginfod server can replay the headers it
received previously from upstream to future downstream. The headers
are placed adjacent to the payload files .cache/debuginfod/BUILDID/PAYLOAD
as .cache/debuginfod/BUILDID/hdr-PAYLOAD. They are aged the same
atime-based way.
Testing via an extension of a previous small test, and hand-running both
client & server code under valgrind. No memcheck errors reported.
Signed-off-by: Frank Ch. Eigler <f...@redhat.com>
diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c
index d89beae93ea1..585855b92c68 100644
--- a/debuginfod/debuginfod-client.c
+++ b/debuginfod/debuginfod-client.c
@@ -569,7 +569,7 @@ debuginfod_clean_cache(debuginfod_client *c,
return -errno;
regex_t re;
- const char * pattern =
".*/(metadata.*|[a-f0-9]+(/debuginfo|/executable|/source.*|))$"; /* include
dirs */
+ const char * pattern =
".*/(metadata.*|[a-f0-9]+(/hdr.*|/debuginfo|/executable|/source.*|))$"; /*
include dirs */
/* NB: also matches .../section/ subdirs, so extracted section files also
get cleaned. */
if (regcomp (&re, pattern, REG_EXTENDED | REG_NOSUB) != 0)
return -ENOMEM;
@@ -1777,7 +1777,9 @@ debuginfod_query_server_by_buildid (debuginfod_client *c,
char *cache_miss_path = NULL;
char *target_cache_dir = NULL;
char *target_cache_path = NULL;
+ char *target_cachehdr_path = NULL;
char *target_cache_tmppath = NULL;
+ char *target_cachehdr_tmppath = NULL;
char suffix[NAME_MAX];
char build_id_bytes[MAX_BUILD_ID_BYTES * 2 + 1];
int vfd = c->verbose_fd;
@@ -1912,6 +1914,8 @@ debuginfod_query_server_by_buildid (debuginfod_client *c,
target_cache_path: $HOME/.cache/0123abcd/debuginfo
target_cache_path: $HOME/.cache/0123abcd/executable-.debug_info
target_cache_path: $HOME/.cache/0123abcd/source-HASH-#PATH#TO#SOURCE
+ target_cachehdr_path: $HOME/.cache/0123abcd/hdr-debuginfo
+ target_cachehdr_path: $HOME/.cache/0123abcd/hdr-executable...
*/
cache_path = make_cache_path();
@@ -1923,11 +1927,15 @@ debuginfod_query_server_by_buildid (debuginfod_client
*c,
xalloc_str (target_cache_dir, "%s/%s", cache_path, build_id_bytes);
(void) mkdir (target_cache_dir, 0700); // failures with this mkdir would be
caught later too
- if (suffix[0] != '\0') /* section, source queries */
+ if (suffix[0] != '\0') { /* section, source queries */
xalloc_str (target_cache_path, "%s/%s-%s", target_cache_dir, type, suffix);
- else
+ xalloc_str (target_cachehdr_path, "%s/hdr-%s-%s", target_cache_dir, type,
suffix);
+ } else {
xalloc_str (target_cache_path, "%s/%s", target_cache_dir, type);
+ xalloc_str (target_cachehdr_path, "%s/hdr-%s", target_cache_dir, type);
+ }
xalloc_str (target_cache_tmppath, "%s.XXXXXX", target_cache_path);
+ xalloc_str (target_cachehdr_tmppath, "%s.XXXXXX", target_cachehdr_path);
/* XXX combine these */
xalloc_str (interval_path, "%s/%s", cache_path,
cache_clean_interval_filename);
@@ -1978,6 +1986,32 @@ debuginfod_query_server_by_buildid (debuginfod_client *c,
/* Success!!!! */
update_atime(fd);
rc = fd;
+
+ /* Attempt to transcribe saved headers. */
+ int fdh = open (target_cachehdr_path, O_RDONLY);
+ if (fdh >= 0)
+ {
+ if (fstat (fdh, &st) == 0 && st.st_size > 0)
+ {
+ c->winning_headers = malloc(st.st_size);
+ if (NULL != c->winning_headers)
+ {
+ ssize_t bytes_read = pread_retry(fdh,
c->winning_headers, st.st_size, 0);
+ if (bytes_read <= 0)
+ {
+ free (c->winning_headers);
+ c->winning_headers = NULL;
+ (void) unlink (target_cachehdr_path);
+ }
+ if (vfd >= 0)
+ dprintf (vfd, "found %s (bytes=%ld)\n",
target_cachehdr_path, bytes_read);
+ }
+ }
+
+ update_atime (fdh);
+ close (fdh);
+ }
+
goto out;
}
else
@@ -2004,12 +2038,12 @@ debuginfod_query_server_by_buildid (debuginfod_client
*c,
/* TOCTOU non-problem: if another task races, puts a working
download or an empty file in its place, unlinking here just
means WE will try to download again as uncached. */
- unlink(target_cache_path);
+ (void) unlink(target_cache_path);
}
}
else if (errno == EACCES)
/* Ensure old 000-permission files are not lingering in the cache. */
- unlink(target_cache_path);
+ (void) unlink(target_cache_path);
if (section != NULL)
{
@@ -2409,6 +2443,22 @@ debuginfod_query_server_by_buildid (debuginfod_client *c,
/* Perhaps we need not give up right away; could retry or something ...
*/
}
+ /* write out the headers, best effort basis */
+ if (c->winning_headers) {
+ int fdh = mkstemp (target_cachehdr_tmppath);
+ if (fdh >= 0) {
+ size_t bytes_to_write = strlen(c->winning_headers)+1; // include \0
+ size_t bytes = pwrite_retry (fdh, c->winning_headers, bytes_to_write, 0);
+ (void) close (fdh);
+ if (bytes == bytes_to_write)
+ (void) rename (target_cachehdr_tmppath, target_cachehdr_path);
+ else
+ (void) unlink (target_cachehdr_tmppath);
+ if (vfd >= 0)
+ dprintf (vfd, "saved %ld bytes of headers to %s\n", bytes,
target_cachehdr_path);
+ }
+ }
+
/* remove all handles from multi */
for (int i = 0; i < num_urls; i++)
{
@@ -2490,8 +2540,11 @@ debuginfod_query_server_by_buildid (debuginfod_client *c,
if (rc < 0 && target_cache_tmppath != NULL)
(void)unlink (target_cache_tmppath);
free (target_cache_tmppath);
-
-
+ if (rc < 0 && target_cachehdr_tmppath != NULL)
+ (void)unlink (target_cachehdr_tmppath);
+ free (target_cachehdr_tmppath);
+ free (target_cachehdr_path);
+
return rc;
}
diff --git a/tests/run-debuginfod-artifact-running.sh
b/tests/run-debuginfod-artifact-running.sh
index 8b9aed37fa12..df42957bfdb9 100755
--- a/tests/run-debuginfod-artifact-running.sh
+++ b/tests/run-debuginfod-artifact-running.sh
@@ -116,4 +116,11 @@ cmp $filename ${PWD}/prog2.c
kill $PID1
wait $PID1
PID1=0
+
+# PR31862: after killing debuginfod, check that the cached version still
exists and holds headers!
+(DEBUGINFOD_VERBOSE=1; export DEBUGINFOD_VERBOSE
+ testrun ${abs_top_builddir}/debuginfod/debuginfod-find -v debuginfo $BUILDID2
2>&1) | tee vlog3
+tempfiles vlog3
+grep -i x-debuginfod vlog3
+
exit 0
