Why does fread() not work for files with html content? - html

Question

I tried to read some files with the following code:
Main:
#define RESPONSE_MAX_LENGTH (1024 * 1024) // Should be 1MB
char file_content[RESPONSE_MAX_LEGNTH];
memset(&file_content, 0, RESPONSE_MAX_LEGNTH);
request_get_file("/User/...", file_content);
Function Declaration:
int request_get_file(char* requested_file_path, char* buf) {
int file_size = 0;
FILE* fp = NULL;
if ((fp = fopen(requested_file_path, "r+")) == NULL) {
return errno;
}
fseek(fp, 0L, SEEK_END);
file_size = (int)ftell(fp);
rewind(fp);
errno = 0;
if (fread(buf, 1, file_size, fp) == 0) {
if (!feof(fp)) {
if (ferror(fp)) {
printf("An error occured while reading the requested file. File size: %d\n", file_size);
perror("fread()");
return errno;
}
}
}
fclose(fp);
}
I am able to read .txt files, but when I open a html file, I get an error saying:
fread(): Bad address (Created with perror("fread"))
errno = 14
For some reason, this error only occurs for some specific documents.
Solution:
I just realized that the problem seems to be related to a specific file. After renaming my test.html to test.txt and trying to open this one, the error is still there. Could that have to do with the file content?
=> Yes, as the buffer I was writing the data was way too small.
How can I fix this issue?

Answer 1

The problem was that the buffer I was writing to was way too small to hold all the data read by fread().
My updated code:
Main:
char* buf = NULL;
request_get_file("/User/...", &buf);
Function Declaration:
int request_get_file(char* requested_file_path, char** buf) {
int file_size = 0;
FILE* fp = NULL;
if ((fp = fopen(requested_file_path, "r+")) == NULL) {
return errno;
}
fseek(fp, 0L, SEEK_END);
file_size = (int)ftell(fp);
rewind(fp);
errno = 0;
if ((*buf = calloc(file_size + 1, sizeof(char))) == NULL) {
perror("calloc()");
return errno;
}
if (fread(*buf, 1, file_size, fp) == 0) {
if (!feof(fp)) {
if (ferror(fp)) {
printf("An error occured while reading the requested file. File size: %d\n", file_size);
perror("fread()");
return errno;
}
}
}
fclose(fp);
}