path: root/grep.c
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authorEmily Shaffer <>2019-05-23 20:23:56 (GMT)
committerJunio C Hamano <>2019-05-28 17:57:07 (GMT)
commitde99eb0c24d96730de187edd37b9ca9d42b0b05d (patch)
treed850dfb2e04809517b048db9733dea477823b3f6 /grep.c
parentaeb582a98374c094361cba1bd756dc6307432c42 (diff)
grep: fail if call could output and name is null
grep_source(), which performs much of the work for Git's grep library, allows passing an arbitrary struct grep_source which represents the text which grep_source() should search to match a pattern in the provided struct grep_opt. In most callers, the grep_source::name field is set to an appropriate prefix to print before a colon when a result matches: README:Git is an Open Source project covered by the GNU General One caller, grep_buffer(), leaves the grep_source::name field set to NULL because there isn't enough context to determine an appropriate name for this kind of output line. In practice, this has been fine: the only caller of grep_buffer() is "git log --grep", and that caller sets grep_opt::status_only, which disables output and only checks whether a match exists. But this is brittle: a future caller can call grep_buffer() without grep_opt::status_only set, and as soon as it hits a match, grep_source() will try to print the match and segfault: (null):Git is an Open Source project covered by the GNU General For example, a future caller might want to print all matching lines from commits which match a regex. Futureproof by diagnosing early a use of the API that could trigger that condition, before we know whether the pattern matches: BUG: grep.c:1783: grep call which could print a name requires be non-NULL Aborted This way, the caller's author gets an indication of how to fix the issue - by providing grep_source::name or setting grep_opt::status_only - and they are warned of the potential for a segfault unconditionally, rather than only if there is a match. Noticed while adding such a call to a tutorial on revision walks. Signed-off-by: Emily Shaffer <> Reviewed-by: Jonathan Nieder <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'grep.c')
1 files changed, 4 insertions, 0 deletions
diff --git a/grep.c b/grep.c
index 0d50598..f7c3a58 100644
--- a/grep.c
+++ b/grep.c
@@ -1780,6 +1780,10 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
enum grep_context ctx = GREP_CONTEXT_HEAD;
xdemitconf_t xecfg;
+ if (!opt->status_only && gs->name == NULL)
+ BUG("grep call which could print a name requires "
+ " be non-NULL");
if (!opt->output)
opt->output = std_output;