PR28284 - Debuginfod header functionality implemented

Debuginfod and debuginfod clients are now equipped to send
and receive http headers prefixed with X-DEBUGINFOD and
print them in verbose mode for more context

Signed-off-by: Noah Sanci <nsanci@redhat.com>

11 files changed, 122 insertions, 8 deletions

diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
index c692a389..8c843f3a 100644
--- a/debuginfod/ChangeLog
+++ b/debuginfod/ChangeLog
@@ -1,3 +1,17 @@
+2022-07-15  Noah Sanci  <nsanci@redhat.com>
+
+        * debuginfod-client.c (header_callback): Handle headers without
+        X-DEBUGINFOD prefix.
+        (debuginfod_query_server): Removed verbose printing headers when
+        undesired.
+        (debuginfod_get_headers): Created.
+        * debuginfod-find.c (main): Verboes printing headers.
+        * debuginfod.cxx (handle_buildid): Add headers prefixed with
+        X-DEBUGINFOD from federated servers to this server's response
+        headers.
+        * debuginfod.h.in (debuginfod_get_headers): Created.
+        * libdebuginfod.map: New elfutils version added.
+
 2022-09-02  Aaron Merey  <amerey@redhat.com>
 
         * debuginfod.cxx (parse_opt): If '-C' is given with no arg, do not
diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c
index b7b65aff..a3565f57 100644
--- a/debuginfod/debuginfod-client.c
+++ b/debuginfod/debuginfod-client.c
@@ -501,6 +501,12 @@ header_callback (char * buffer, size_t size, size_t numitems, void * userdata)
 {
   if (size != 1)
     return 0;
+  // X-DEBUGINFOD is 11 characters long.
+  // Some basic checks to ensure the headers received are of the expected format
+  if ( strncmp(buffer, "X-DEBUGINFOD", 11) || buffer[numitems-1] != '\n'
+       || (buffer == strstr(buffer, ":")) ){
+    return numitems;
+  }
   /* Temporary buffer for realloc */
   char *temp = NULL;
   struct handle_data *data = (struct handle_data *) userdata;
@@ -1111,8 +1117,6 @@ debuginfod_query_server (debuginfod_client *c,
                 if (c->winning_headers == NULL)
                   {
                     c->winning_headers = data[committed_to].response_data;
-                    if (vfd >= 0 && c->winning_headers != NULL)
-                      dprintf(vfd, "\n%s", c->winning_headers);
                     data[committed_to].response_data = NULL;
                     data[committed_to].response_data_size = 0;
                   }
@@ -1542,6 +1546,12 @@ debuginfod_get_url(debuginfod_client *client)
   return client->url;
 }
 
+const char *
+debuginfod_get_headers(debuginfod_client *client)
+{
+  return client->winning_headers;
+}
+
 void
 debuginfod_end (debuginfod_client *client)
 {
diff --git a/debuginfod/debuginfod-find.c b/debuginfod/debuginfod-find.c
index f60b5463..fb1f294c 100644
--- a/debuginfod/debuginfod-find.c
+++ b/debuginfod/debuginfod-find.c
@@ -215,6 +215,9 @@ main(int argc, char** argv)
 
   if (verbose)
     {
+      const char* headers = debuginfod_get_headers(client);
+      if (headers)
+        fprintf(stderr, "Headers:\n%s", headers);
       const char* url = debuginfod_get_url (client);
       if (url != NULL)
         fprintf(stderr, "Downloaded from %s\n", url);
diff --git a/debuginfod/debuginfod.cxx b/debuginfod/debuginfod.cxx
index 8680c048..27b671d3 100644
--- a/debuginfod/debuginfod.cxx
+++ b/debuginfod/debuginfod.cxx
@@ -2093,6 +2093,24 @@ and will not query the upstream servers");
             {
               add_mhd_response_header (r, "Content-Type",
                                        "application/octet-stream");
+              const char * hdrs = debuginfod_get_headers(client);
+              string header_dup;
+              if (hdrs)
+                header_dup = string(hdrs);
+              size_t pos = 0;
+              // Clean winning headers to add all X-DEBUGINFOD lines to the package we'll send
+              while( (pos = header_dup.find("X-DEBUGINFOD")) != string::npos)
+                {
+                  // Focus on where X-DEBUGINFOD- begins
+                  header_dup = header_dup.substr(pos);
+                  size_t newline =  header_dup.find('\n');
+                  if (newline == string::npos)
+                    break;
+                  add_mhd_response_header(r, header_dup.substr(0,header_dup.find(':')).c_str(),
+                                             header_dup.substr(header_dup.find(':')).c_str());
+                  header_dup = header_dup.substr(newline);
+                }
+
               add_mhd_last_modified (r, s.st_mtime);
               if (verbose > 1)
                 obatched(clog) << "serving file from upstream debuginfod/cache" << endl;
diff --git a/debuginfod/debuginfod.h.in b/debuginfod/debuginfod.h.in
index c358df4d..6ae8b91c 100644
--- a/debuginfod/debuginfod.h.in
+++ b/debuginfod/debuginfod.h.in
@@ -93,6 +93,10 @@ void* debuginfod_get_user_data (debuginfod_client *client);
 /* Get the current or last active URL, if known.  */
 const char* debuginfod_get_url (debuginfod_client *client);
 
+/* Returns all headers sent to this client which were prefixed
+ * with X-DEBUGINFOD */
+const char* debuginfod_get_headers(debuginfod_client *client);
+
 /* Add an outgoing HTTP request  "Header: Value".  Copies string.  */
 int debuginfod_add_http_header (debuginfod_client *client, const char* header);
 
diff --git a/debuginfod/libdebuginfod.map b/debuginfod/libdebuginfod.map
index 7d2f5882..f95b5b9a 100644
--- a/debuginfod/libdebuginfod.map
+++ b/debuginfod/libdebuginfod.map
@@ -18,3 +18,6 @@ ELFUTILS_0.179 {
 ELFUTILS_0.183 {
   debuginfod_set_verbose_fd;
 } ELFUTILS_0.179;
+ELFUTILS_0.189 {
+  debuginfod_get_headers;
+} ELFUTILS_0.183;
diff --git a/doc/ChangeLog b/doc/ChangeLog
index 3fff1a84..c2a01a04 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,8 @@
+2022-07-15  Noah Sanci  <nsanci@redhat.com>
+        * debuginfod_find_debuginfo.3: Explained debuginfod_get_headers
+        usage.
+        * debuginfod_get_headers.3: Created.
+
 2022-09-02  Aaron Merey  <amerey@redhat.com>
 
         * debuginfod.8 (-C): Update description.
diff --git a/doc/debuginfod_find_debuginfo.3 b/doc/debuginfod_find_debuginfo.3
index 30cef3c1..984fda12 100644
--- a/doc/debuginfod_find_debuginfo.3
+++ b/doc/debuginfod_find_debuginfo.3
@@ -58,6 +58,7 @@ OPTIONAL FUNCTIONS
 .BI "const char* debuginfod_get_url(debuginfod_client *" client ");"
 .BI "int debuginfod_add_http_header(debuginfod_client *" client ","
 .BI "                               const char* " header ");"
+.BI "const char* debuginfod_get_headers(debuginfod_client *" client ");"
 
 .SH DESCRIPTION
 
@@ -198,6 +199,18 @@ By default, the library adds a descriptive \fIUser-Agent:\fP
 header to outgoing requests.  If the client application adds
 a header with the same name, this default is suppressed.
 
+.BR \%debuginfod_get_headers ()
+may be called with a debuginfod client. This function will return the
+http response headers prefixed with
+.BR X-DEBUGINFOD
+received from the first handle to get a response from a debuginfod server.
+Note that all other http headers aren't stored in the libcurl header
+callback function since they aren't of as much interest. The caller should
+copy the returned string if it is needed beyond the release of the client object.
+The returned string may be NULL if no headers are prefixed with
+.BR X-DEBUGINFOD
+\.
+
 .SH "MACROS"
 
 .SS "DEBUGINFOD_SONAME"
diff --git a/doc/debuginfod_get_headers.3 b/doc/debuginfod_get_headers.3
new file mode 100644
index 00000000..1db55982
--- /dev/null
+++ b/doc/debuginfod_get_headers.3
@@ -0,0 +1,2 @@
+.so man3/debuginfod_find_debuginfo.3
+
diff --git a/tests/ChangeLog b/tests/ChangeLog
index d2952cc9..659bfa19 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,9 @@
+2022-07-15  Noah Sanci  <nsanci@redhat.com>
+
+        * run-debuginfod-response-headers.sh: Added test
+        to ensure that federated servers pass headers down to
+        queried server.
+
 2022-08-04  Sergei Trofimovich  <slyich@gmail.com>
 
         * low_high_pc.c (handle_die): Drop redundant 'lx' suffix.
diff --git a/tests/run-debuginfod-response-headers.sh b/tests/run-debuginfod-response-headers.sh
index 62c43887..e5698cc9 100755
--- a/tests/run-debuginfod-response-headers.sh
+++ b/tests/run-debuginfod-response-headers.sh
@@ -73,17 +73,21 @@ rm -rf $DEBUGINFOD_CACHE_PATH
 env DEBUGINFOD_URLS="http://127.0.0.1:"$PORT1 LD_LIBRARY_PATH=$ldpath ${abs_top_builddir}/debuginfod/debuginfod-find\
     -vvv executable F/prog > vlog-find$PORT1.1 2>&1
 tempfiles vlog-find$PORT1.1
-grep 'Content-Length: ' vlog-find$PORT1.1
-grep 'X-DEBUGINFOD-FILE: ' vlog-find$PORT1.1
-grep 'X-DEBUGINFOD-SIZE: ' vlog-find$PORT1.1
+errfiles vlog-find$PORT1.1
+cat vlog-find$PORT1.1
+grep 'Headers:' vlog-find$PORT1.1
+grep 'X-DEBUGINFOD-FILE: prog' vlog-find$PORT1.1
+grep 'X-DEBUGINFOD-SIZE: '     vlog-find$PORT1.1
 
 # Check to see if an executable file located in an archive prints the file's description and archive
 env DEBUGINFOD_URLS="http://127.0.0.1:"$PORT1 LD_LIBRARY_PATH=$ldpath ${abs_top_builddir}/debuginfod/debuginfod-find\
     -vvv executable c36708a78618d597dee15d0dc989f093ca5f9120 > vlog-find$PORT1.2 2>&1
 tempfiles vlog-find$PORT1.2
-grep 'Content-Length: ' vlog-find$PORT1.2
-grep 'X-DEBUGINFOD-FILE: ' vlog-find$PORT1.2
-grep 'X-DEBUGINFOD-SIZE: ' vlog-find$PORT1.2
+errfiles vlog-find$PORT1.2
+cat vlog-find$PORT1.2
+grep 'Headers:'               vlog-find$PORT1.2
+grep 'X-DEBUGINFOD-FILE: '    vlog-find$PORT1.2
+grep 'X-DEBUGINFOD-SIZE: '    vlog-find$PORT1.2
 grep 'X-DEBUGINFOD-ARCHIVE: ' vlog-find$PORT1.2
 
 # Check that X-DEBUGINFOD-SIZE matches the size of each file
@@ -94,6 +98,38 @@ do
     test $st_size -eq $x_debuginfod_size
 done
 
+rm -rf $DEBUGINFOD_CACHE_PATH
+BUILDID=`env LD_LIBRARY_PATH=$ldpath ${abs_builddir}/../src/readelf \
+          -a F/prog | grep 'Build ID' | cut -d ' ' -f 7`
+netcat_dir="buildid/$BUILDID/"
+mkdir -p ${PWD}/$netcat_dir
+cp F/prog ${PWD}/$netcat_dir/executable
+tempfiles F/prog
+
+# Netcat dies after answering the request
+nc -l -p $PORT2 -c 'echo -e "HTTP/1.1 200 OK\nX-DEBUGINFOD-SIZE: ba:d_size\nX-DEBUGINFOD-\rFILE:\=\+ \r213\n\n $(date)"' & < ${PWD}/$netcat_dir"executable" &
+# Wait until the netcat port is in use. Otherwise debuginfod-find can query
+# before netcat is ready.
+SECONDS=0
+nc_start=$SECONDS
+while [ ! $(lsof -i -P -n | grep LISTEN | grep "nc.*$PORT2")  ]
+do
+  # If it takes longer than 5 seconds for netcat to start up, then fail
+  duration=$(( SECONDS - nc_start ))
+  if [ $SECONDS -gt 5 ]
+  then
+    err
+  fi
+done
+
+env DEBUGINFOD_URLS="http://127.0.0.1:"$PORT2 LD_LIBRARY_PATH=$ldpath ${abs_top_builddir}/debuginfod/debuginfod-find\
+    -vvv executable $BUILDID > vlog-find$PORT2 2>&1
+errfiles vlog-find$PORT2
+tempfiles vlog-find$PORT2
+cat vlog-find$PORT2 | grep "X-DEBUGINFOD-"
+rm -f "$netcat_dir"executable
+rmdir -p $netcat_dir
+
 kill $PID1
 wait $PID1
 PID1=0