From aa7d6520e6335f9ed45ca2bf0fbf932fb4b2dea6 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Mon, 25 Mar 2024 13:34:42 +0100 Subject: [PATCH] avutil/opt: Avoid av_strdup(NULL) It is not documented to be safe and in any case it is nonsense: Currently av_strdup(NULL) returns NULL and in order to distinguish this from a genuine allocation failure, opt_copy_elem() checked afterwards whether src was actually NULL. But then one can simply check in advance whether one should call av_strdup() at all. set_string() was even worse and returned ENOMEM in case the value to be duplicated is NULL; this only worked because av_opt_set_defaults2() does not check the return value at all (given that it can't propagate it). These two places account for 389114 of 390356 av_strdup(NULL) calls during one FATE run. Signed-off-by: Andreas Rheinhardt --- libavutil/opt.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/libavutil/opt.c b/libavutil/opt.c index 685206f416..00e11d1341 100644 --- a/libavutil/opt.c +++ b/libavutil/opt.c @@ -309,6 +309,8 @@ static int set_string_binary(void *obj, const AVOption *o, const char *val, uint static int set_string(void *obj, const AVOption *o, const char *val, uint8_t **dst) { av_freep(dst); + if (!val) + return 0; *dst = av_strdup(val); return *dst ? 0 : AVERROR(ENOMEM); } @@ -2032,9 +2034,11 @@ static int opt_copy_elem(void *logctx, enum AVOptionType type, if (type == AV_OPT_TYPE_STRING) { if (*dst8 != *src8) av_freep(dst8); - *dst8 = av_strdup(*src8); - if (*src8 && !*dst8) - return AVERROR(ENOMEM); + if (*src8) { + *dst8 = av_strdup(*src8); + if (!*dst8) + return AVERROR(ENOMEM); + } } else if (type == AV_OPT_TYPE_BINARY) { int len = *(const int *)(src8 + 1); if (*dst8 != *src8)