Fopen segmentation error?

Question

[RaymanPy]

valgrind:

***
==489682== HEAP SUMMARY:
==489682==     in use at exit: 472 bytes in 1 blocks
==489682==   total heap usage: 2 allocs, 1 frees, 4,568 bytes allocated
==489682== 
==489682== 472 bytes in 1 blocks are still reachable in loss record 1 of 1
==489682==    at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==489682==    by 0x48E8AAD: __fopen_internal (iofopen.c:65)
==489682==    by 0x48E8AAD: fopen@@GLIBC_2.2.5 (iofopen.c:86)
==489682==    by 0x109805: BMP_openfile (in /home/riz/Desktop/SPBU/4-task/bmp.o)
==489682==    by 0x109A4C: main (in /home/riz/Desktop/SPBU/4-task/bmp.o)
==489682== 
==489682== LEAK SUMMARY:
==489682==    definitely lost: 0 bytes in 0 blocks
==489682==    indirectly lost: 0 bytes in 0 blocks
==489682==      possibly lost: 0 bytes in 0 blocks
==489682==    still reachable: 472 bytes in 1 blocks
==489682==         suppressed: 0 bytes in 0 blocks
==489682== 
***
Segmentation fault (core dumped)

Код:

int BMP_openfile(){
    
    struct BMP_HEADER *header;
    struct BMP_INFO *info;

    FILE *fp = fopen("sample_24.bmp","rb");
    if(fp == NULL){
        fprintf(stdout, "Error open file.");
        return EXIT_FAILURE;
    }
    
    fread(&header,sizeof(BITMAPFILEHEADER),1,fp); 
    fread(&info,sizeof(BITMAPINFOHEADER),1,fp);

    if (header->file_type != 19778){
        fprintf(stdout,"Error format. The converter only supports BMP format.");
        fclose(fp);
        return -1;
    }
    if (info->planes != 1){
        fprintf(stdout, "Error planes. The number of planes must be 1.");
        fclose(fp);
        return -2;
    }
    if (info->bpp != 8 && info->bpp != 24){
        fprintf(stdout,"Error bits per pixel error. The converter only supports 8 and 24 bits per pixel images.");
        fclose(fp);
        return -2;
    }
    if(info->compression != 0){
        fprintf(stdout, "Error compression. Only uncompressed images are supported");
        fclose(fp);
        return -2;
    }

 //fseek(fp,header->pixel_data_offset,SEEK_SET);
    struct Image *picture = BMP_readImage(info,fp,info->width,info->height);
    if(!picture){
        fclose(fp);
        return -1;
    }
    
    free(fp);
    fclose(fp);
    
    create_BMP_Image(header,info,picture);
    free_Image(picture);
    return 0;
}


int main(){
    BMP_openfile();
    return 0;
}

Answer 1

[Wataru]

Еще ошибка:

struct BMP_HEADER *header;
...
 fread(&header,sizeof(BITMAPFILEHEADER),1,fp);

header - это указатель. 8 байт (на 64-битных системах). Вы в указатель (переменную-адрес) читаете структуру BITMAPFILEHEADER, сколько бы байт оно не было. Вряд ли это то, что вы хотели сделать.

Надо выделять BMP_HEADER через malloc или на стеке (как локальную переменную, а не указатель). И передавать в fread указатель на структуру, а не адрес указателя. То же самое со второй структурой.

Answer 2

[Максим Гришин]

free(fp);
fclose(fp);

Вот тут ошибка, сначала fclose, потом free.