[PATCH 08/10] debuginfod: Make sure suffix can place zero terminator when copying filename

[Mark Wielaard <mark@klomp.org>]

We need to make sure that we can always place a zero terminator at
the end of suffix when we are copying the filename. So add one more
char to the suffix array. And make sure that we can always add an
extra escape character when we need to escape the current character.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 debuginfod/ChangeLog           | 5 +++++
 debuginfod/debuginfod-client.c | 4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
index 66511a3f..9ff2e111 100644
--- a/debuginfod/ChangeLog
+++ b/debuginfod/ChangeLog
@@ -1,3 +1,8 @@
+2020-06-16  Mark Wielaard  <mark@klomp.org>
+
+	* debuginfod-client.c (debuginfod_query_server): Increase suffix
+	array and prepare having to escape 1 character with 2.
+
 2020-06-16  Mark Wielaard  <mark@klomp.org>
 
 	* debuginfod-client.c (debuginfod_clean_cache): Handle failing
diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c
index 0cfc6dfc..e9c2ca83 100644
--- a/debuginfod/debuginfod-client.c
+++ b/debuginfod/debuginfod-client.c
@@ -474,7 +474,7 @@ debuginfod_query_server (debuginfod_client *c,
   char *target_cache_dir = NULL;
   char *target_cache_path = NULL;
   char *target_cache_tmppath = NULL;
-  char suffix[PATH_MAX];
+  char suffix[PATH_MAX + 1]; /* +1 for zero terminator.  */
   char build_id_bytes[MAX_BUILD_ID_BYTES * 2 + 1];
   int rc;
 
@@ -511,7 +511,7 @@ debuginfod_query_server (debuginfod_client *c,
 
       /* copy the filename to suffix, s,/,#,g */
       unsigned q = 0;
-      for (unsigned fi=0; q < PATH_MAX-1; fi++)
+      for (unsigned fi=0; q < PATH_MAX-2; fi++) /* -2, escape is 2 chars.  */
         switch (filename[fi])
           {
           case '\0':
-- 
2.18.4