ffmpeg_mbedtls_bug.c

// gcc main.c -lavformat -lavfilter -lavcodec -lavutil -lm -lpthread -lmbedtls -lswscale -lswresample -lz -lmbedx509 -lmbedcrypto -lmp3lame

/*
*   To get the desired bug, compile ffmpeg with mbedtls support.
*
*   This will loop until either no more fd can be opened, or an error happens when trying to open the url.
*   
*   Check the value fd after each time avformat_open_input is called.
*   Try this with a http / local file and you will notice that fd will keep the vallue of 3 (0=stdin, 1=stout, 2=stderr)
*
*   Try this same test with ffmpeg compiled with openssl, the program will behave correctly.
*/


#include <stdio.h>      //printf
#include <unistd.h>     //open
#include <fcntl.h>      //close

#include <libavformat/avformat.h>


// example https url.
#define URL "https://www.radiantmediaplayer.com/media/bbb-360p.mp4"


int main(int argc, char *argv[])
{
    while (1)
    {
        int fd = open(argv[0], O_RDONLY);
        {
            printf("opened %d\n", fd);
            close(fd);
        }
        if (fd == -1)
        {
            printf("failed to open fd\n");
            return -1;
        }
        AVFormatContext *format_ctx = {0};
        if (avformat_open_input(&format_ctx, URL, NULL, NULL))
        {
            printf("failed to open ctx\n");
            return -1;
        }
        avformat_close_input(&format_ctx);
    }
}