fftools/ffmpeg_opt: Improve checks for truncation/alloc error

Do this by switching from the dynamic buffer API to the AVBPrint API;
the former has no defined way to check for errors.
This also avoids allocating an AVIOContext.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index a703798586..0dd18d2127 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -34,6 +34,7 @@
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/avutil.h"
+#include "libavutil/bprint.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/fifo.h"
@@ -1645,29 +1646,26 @@ static void parse_matrix_coeffs(uint16_t *dest, const char *str)
 }
 
 /* read file contents into a string */
-static uint8_t *read_file(const char *filename)
+static char *read_file(const char *filename)
 {
     AVIOContext *pb      = NULL;
-    AVIOContext *dyn_buf = NULL;
     int ret = avio_open(&pb, filename, AVIO_FLAG_READ);
-    uint8_t buf[1024], *str;
+    AVBPrint bprint;
+    char *str;
 
     if (ret < 0) {
         av_log(NULL, AV_LOG_ERROR, "Error opening file %s.\n", filename);
         return NULL;
     }
 
-    ret = avio_open_dyn_buf(&dyn_buf);
+    av_bprint_init(&bprint, 0, AV_BPRINT_SIZE_UNLIMITED);
+    ret = avio_read_to_bprint(pb, &bprint, SIZE_MAX);
+    avio_closep(&pb);
     if (ret < 0) {
-        avio_closep(&pb);
+        av_bprint_finalize(&bprint, NULL);
         return NULL;
     }
-    while ((ret = avio_read(pb, buf, sizeof(buf))) > 0)
-        avio_write(dyn_buf, buf, ret);
-    avio_w8(dyn_buf, 0);
-    avio_closep(&pb);
-
-    ret = avio_close_dyn_buf(dyn_buf, &str);
+    ret = av_bprint_finalize(&bprint, &str);
     if (ret < 0)
         return NULL;
     return str;
@@ -3276,7 +3274,7 @@ static int opt_filter_complex(void *optctx, const char *opt, const char *arg)
 static int opt_filter_complex_script(void *optctx, const char *opt, const char *arg)
 {
     FilterGraph *fg;
-    uint8_t *graph_desc = read_file(arg);
+    char *graph_desc = read_file(arg);
     if (!graph_desc)
         return AVERROR(EINVAL);