Find libc's write when git writes first

A Lua build replaces write, and git can write before cmd_main reaches
cgit_init_filters, as it does when GIT_TRACE2 is set, which called
through a null pointer and crashed every request.

2 files changed, 12 insertions, 0 deletions

diff --git a/source/filter.c b/source/filter.cindex 43ba70a..f2dfe12 100644--- a/source/filter.c+++ b/source/filter.c@@ -166,6 +166,10 @@ void cgit_init_filters(void)  */ ssize_t write(int fd, const void *buf, size_t count) {+	// Git can write before cmd_main reaches cgit_init_filters, to a trace+	// target for one, so libc's write may still need looking up here.+	if (!libc_write)+		cgit_init_filters(); 	if (fd != STDOUT_FILENO || !filter_write) 		return libc_write(fd, buf, count); 	return filter_write(current_write_filter, buf, count);
diff --git a/source/filter.c b/source/filter.c
index 43ba70a..f2dfe12 100644
--- a/source/filter.c
+++ b/source/filter.c
@@ -166,6 +166,10 @@ void cgit_init_filters(void)
  */
 ssize_t write(int fd, const void *buf, size_t count)
 {
+	// Git can write before cmd_main reaches cgit_init_filters, to a trace
+	// target for one, so libc's write may still need looking up here.
+	if (!libc_write)
+		cgit_init_filters();
 	if (fd != STDOUT_FILENO || !filter_write)
 		return libc_write(fd, buf, count);
 	return filter_write(current_write_filter, buf, count);
diff --git a/tests/t0201-filters.sh b/tests/t0201-filters.shindex 1ffb973..3987bdc 100755--- a/tests/t0201-filters.sh+++ b/tests/t0201-filters.sh@@ -163,4 +163,12 @@ test_expect_success CGIT_LUA 'a lua filter that writes while loading still rende 	grep "</html>" tmp ' +# A Lua build replaces write, and git writes its trace before cgit has run a+# line of its own.+test_expect_success CGIT_LUA 'git can trace before the filters are set up' '+	CGIT_CONFIG="$PWD/cgitrc" GIT_TRACE2="$PWD/trace2.out" QUERY_STRING="url=foo/" cgit >tmp &&+	grep "</html>" tmp &&+	test -s trace2.out+'+ test_done
diff --git a/tests/t0201-filters.sh b/tests/t0201-filters.sh
index 1ffb973..3987bdc 100755
--- a/tests/t0201-filters.sh
+++ b/tests/t0201-filters.sh
@@ -163,4 +163,12 @@ test_expect_success CGIT_LUA 'a lua filter that writes while loading still rende
 	grep "</html>" tmp
 '
 
+# A Lua build replaces write, and git writes its trace before cgit has run a
+# line of its own.
+test_expect_success CGIT_LUA 'git can trace before the filters are set up' '
+	CGIT_CONFIG="$PWD/cgitrc" GIT_TRACE2="$PWD/trace2.out" QUERY_STRING="url=foo/" cgit >tmp &&
+	grep "</html>" tmp &&
+	test -s trace2.out
+'
+
 test_done