[PATCH v3 1/7] banned-die: create header for banning of functions

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <stolee@gmail.com>

We have universally-banned functions listed in banned.h since
c8af66ab8ad (automatically ban strcpy(), 2018-07-26), but some layers of
the code should be more strict than others.

One such example is the trace2 API which runs during atexit() and can
prove to cause die()-handler recursion problems if it calls die().

Create a new banned-die.h header file that will ban some Git methods
that call die(). Include that in all trace2 API implementation files.
This currently only bans die() itself, and that was already not used.

It would be reasonable to name this file trace2/tr2_banned.h to be
specific to the trace2 API, but it seems like such a restriction would
be valuable to put in some other areas of the code, so adding it at the
root of the tree seems like a good long-term approach.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
---
 banned-die.h            | 14 ++++++++++++++
 trace2.c                |  2 ++
 trace2/tr2_cfg.c        |  2 ++
 trace2/tr2_cmd_name.c   |  2 ++
 trace2/tr2_ctr.c        |  2 ++
 trace2/tr2_dst.c        |  2 ++
 trace2/tr2_sid.c        |  2 ++
 trace2/tr2_sysenv.c     |  2 ++
 trace2/tr2_tbuf.c       |  2 ++
 trace2/tr2_tgt_event.c  |  2 ++
 trace2/tr2_tgt_normal.c |  2 ++
 trace2/tr2_tgt_perf.c   |  2 ++
 trace2/tr2_tls.c        |  2 ++
 trace2/tr2_tmr.c        |  2 ++
 14 files changed, 40 insertions(+)
 create mode 100644 banned-die.h

diff --git a/banned-die.h b/banned-die.h
new file mode 100644
index 0000000000..1cde4035c1
--- /dev/null
+++ b/banned-die.h
@@ -0,0 +1,14 @@
+#ifndef BANNED_DIE_H
+#define BANNED_DIE_H
+
+#include "banned.h"
+
+/*
+ * This header lists functions that must not be used by low-level APIs
+ * because they can cause Git to terminate.
+ */
+
+#undef die
+#define die BANNED(die)
+
+#endif /* BANNED_DIE_H */
diff --git a/trace2.c b/trace2.c
index c23c0a227b..8c974dee87 100644
--- a/trace2.c
+++ b/trace2.c
@@ -17,6 +17,8 @@
 #include "trace2/tr2_tgt.h"
 #include "trace2/tr2_tls.h"
 #include "trace2/tr2_tmr.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 static int trace2_enabled;
 static int trace2_redact = 1;
diff --git a/trace2/tr2_cfg.c b/trace2/tr2_cfg.c
index bbcfeda60a..757dfeae8d 100644
--- a/trace2/tr2_cfg.c
+++ b/trace2/tr2_cfg.c
@@ -7,6 +7,8 @@
 #include "trace2/tr2_cfg.h"
 #include "trace2/tr2_sysenv.h"
 #include "wildmatch.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 static struct string_list tr2_cfg_patterns = STRING_LIST_INIT_DUP;
 static int tr2_cfg_loaded;
diff --git a/trace2/tr2_cmd_name.c b/trace2/tr2_cmd_name.c
index b7b5a869b7..f378bef4cf 100644
--- a/trace2/tr2_cmd_name.c
+++ b/trace2/tr2_cmd_name.c
@@ -1,6 +1,8 @@
 #include "git-compat-util.h"
 #include "strbuf.h"
 #include "trace2/tr2_cmd_name.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 #define TR2_ENVVAR_PARENT_NAME "GIT_TRACE2_PARENT_NAME"
 
diff --git a/trace2/tr2_ctr.c b/trace2/tr2_ctr.c
index ee17bfa86b..20618a65b2 100644
--- a/trace2/tr2_ctr.c
+++ b/trace2/tr2_ctr.c
@@ -2,6 +2,8 @@
 #include "trace2/tr2_tgt.h"
 #include "trace2/tr2_tls.h"
 #include "trace2/tr2_ctr.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 /*
  * A global counter block to aggregate values from the partial sums
diff --git a/trace2/tr2_dst.c b/trace2/tr2_dst.c
index 5be892cd5c..555ac7cb9e 100644
--- a/trace2/tr2_dst.c
+++ b/trace2/tr2_dst.c
@@ -5,6 +5,8 @@
 #include "trace2/tr2_dst.h"
 #include "trace2/tr2_sid.h"
 #include "trace2/tr2_sysenv.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 /*
  * How many attempts we will make at creating an automatically-named trace file.
diff --git a/trace2/tr2_sid.c b/trace2/tr2_sid.c
index 131b4f5a62..1d4f018f66 100644
--- a/trace2/tr2_sid.c
+++ b/trace2/tr2_sid.c
@@ -3,6 +3,8 @@
 #include "strbuf.h"
 #include "trace2/tr2_tbuf.h"
 #include "trace2/tr2_sid.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 #define TR2_ENVVAR_PARENT_SID "GIT_TRACE2_PARENT_SID"
 
diff --git a/trace2/tr2_sysenv.c b/trace2/tr2_sysenv.c
index 4abc218514..7fa58eba91 100644
--- a/trace2/tr2_sysenv.c
+++ b/trace2/tr2_sysenv.c
@@ -4,6 +4,8 @@
 #include "config.h"
 #include "dir.h"
 #include "tr2_sysenv.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 /*
  * Each entry represents a trace2 setting.
diff --git a/trace2/tr2_tbuf.c b/trace2/tr2_tbuf.c
index c3b3822ed7..d623e55a81 100644
--- a/trace2/tr2_tbuf.c
+++ b/trace2/tr2_tbuf.c
@@ -1,5 +1,7 @@
 #include "git-compat-util.h"
 #include "tr2_tbuf.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 void tr2_tbuf_local_time(struct tr2_tbuf *tb)
 {
diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c
index 5a0381791f..36a746cc10 100644
--- a/trace2/tr2_tgt_event.c
+++ b/trace2/tr2_tgt_event.c
@@ -13,6 +13,8 @@
 #include "trace2/tr2_tgt.h"
 #include "trace2/tr2_tls.h"
 #include "trace2/tr2_tmr.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 static struct tr2_dst tr2dst_event = {
 	.sysenv_var = TR2_SYSENV_EVENT,
diff --git a/trace2/tr2_tgt_normal.c b/trace2/tr2_tgt_normal.c
index 924736ab36..82995e510f 100644
--- a/trace2/tr2_tgt_normal.c
+++ b/trace2/tr2_tgt_normal.c
@@ -11,6 +11,8 @@
 #include "trace2/tr2_tgt.h"
 #include "trace2/tr2_tls.h"
 #include "trace2/tr2_tmr.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 static struct tr2_dst tr2dst_normal = {
 	.sysenv_var = TR2_SYSENV_NORMAL,
diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c
index 4eb9289f95..96a5bc7f10 100644
--- a/trace2/tr2_tgt_perf.c
+++ b/trace2/tr2_tgt_perf.c
@@ -14,6 +14,8 @@
 #include "trace2/tr2_tgt.h"
 #include "trace2/tr2_tls.h"
 #include "trace2/tr2_tmr.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 static struct tr2_dst tr2dst_perf = {
 	.sysenv_var = TR2_SYSENV_PERF,
diff --git a/trace2/tr2_tls.c b/trace2/tr2_tls.c
index 7b023c1bfc..49bd505d62 100644
--- a/trace2/tr2_tls.c
+++ b/trace2/tr2_tls.c
@@ -3,6 +3,8 @@
 #include "thread-utils.h"
 #include "trace.h"
 #include "trace2/tr2_tls.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 /*
  * Initialize size of the thread stack for nested regions.
diff --git a/trace2/tr2_tmr.c b/trace2/tr2_tmr.c
index 038181ad9b..275091c693 100644
--- a/trace2/tr2_tmr.c
+++ b/trace2/tr2_tmr.c
@@ -3,6 +3,8 @@
 #include "trace2/tr2_tls.h"
 #include "trace2/tr2_tmr.h"
 #include "trace.h"
+/* banned-die must be last. */
+#include "banned-die.h"
 
 #define MY_MAX(a, b) ((a) > (b) ? (a) : (b))
 #define MY_MIN(a, b) ((a) < (b) ? (a) : (b))
-- 
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