用C调试Web服务器

我在课程中PSET6的

server.c

文件中有一个错误，但不知道如何找到它。我正在尝试使用GDB，但它似乎不是很有用

我希望能得到一些帮助，学习如何更好地调试这种程序，如果你能看看我的代码，看看你是否能从一开始就发现任何问题

我的github是：

我关注的职能是：

 /**
 * Loads a file into memory dynamically allocated on heap.
 * Stores address thereof in *content and length thereof in *length.
 */
bool load(FILE* file, BYTE** content, size_t* length)
{
    //get the actual length of the file by finding pointer at the end of file and have it reruend via ftell()
    fseek(file, 0, SEEK_END);
    *length = ftell(file);
    fseek(file, 0, SEEK_SET);

    //initialize memory and all for storing the file chars, use calloc to be able to diff. garbage
    char* get_chars = calloc(sizeof(char) * (*length), sizeof(char));
    if (get_chars == NULL)
        return false;

    //read in chars if interpreter file to new variable get_chars
    fread(get_chars, *length, sizeof(BYTE), file);

    //save the chars address into the pointer we want for content
    *content = get_chars;

    free(get_chars); 
    fclose(file);

    if (*content != NULL)
        return true;
    else 
        return false;
}

及

及 /** *返回受支持扩展的MIME类型，否则为NULL。 */

最后

 /**
 * Parses a request-line, storing its absolute-path at abs_path 
 * and its query string at query, both of which are assumed
 * to be at least of length LimitRequestLine + 1.
 */

bool parse(const char* line, char* abs_path, char* query)
{
    int length = strlen(line) + 1;

    //copy the line into new so we can use strsep and null over chars
    char* copyline = malloc(sizeof(char) * length);
    strncpy(copyline, line, length);

    //find token deliminated by space and repeat with NULL to use same string
    char* method = strtok(copyline, " ");
    char* request = strtok(NULL, " ");
    char* version = strtok(NULL, " ");

    //return error 405 if method is not GET, string compare method to find out
    if (strcmp(method, "GET") != 0)
    {
        error(405);
        return false;
    }

    //return error 502 if request-target does not start with /
    if (*request != '/')
    {
        error(501);
        return false;
    }

    //if there is a " in the reuest, return an error 
    if (strchr("\"", *request) != NULL)
    { 
        error(400);
        return false;
    }

    //HTTP version has to be 1.1
    if (strcmp(version, "HTTP/1.1\r\n") != 0)
    {
         error(505);
        return false;
    }

    //if there is no query, return nothing for query and copy the requst in absoulte path
    if (strchr(request, '?') == NULL)
    {
        strcpy(query, "");
        strncpy(abs_path, request, strlen(request));
    }

    //if there is a query
    else
    {
         //will store before ? as a token and after ? as the second token. see test.c
        strcpy(abs_path, strtok(request, "?"));
        strcpy(query, strtok(NULL, "?"));
    }

    //add null-terminator to the end of paths 
    //abs_path[strlen(abs_path)] = '/0';
    //query[strlen(query)] = '/0';
    strcat(abs_path, "\0");
    strcat(query, "\0");

    free(copyline);

    return true;

}

---

您不能在

load

功能中

释放（获取字符）

。这将释放您刚才分配的缓冲区，并将

*内容

指向无效地址。谢谢，我已进行了编辑。然而，它仍然不起作用。我相信现在是索引函数。

const char* lookup(const char* path)
{
    //check if path is given
    if (path == NULL)
    {
        return NULL;
    }

    //returns pointer of last occurance of '.'
    char* extension = strrchr(path,'.');

    //compares the ext. to the actual ext. given and returns correct format
    if (strcasecmp("css", extension) == 0)
    {
        return "text/css";
    }

    else if (strcasecmp("html", extension) == 0)
    {
        return "text/html";
    }

    else if (strcasecmp("gif", extension) == 0)
    {
          return "image/gif";
    }

    else if (strcasecmp("ico", extension) == 0)
    {
     return "image/x-icon";
    }

    else if (strcasecmp("jpg", extension) == 0)
    {
         return "image/jpeg";
    }

    else if (strcasecmp("js", extension) == 0)
    {
         return "text/javascript";
    }

    else if (strcasecmp("png", extension) == 0)
    {
         return "image/png";
    }

    else
        return NULL;  

}

 /**
 * Parses a request-line, storing its absolute-path at abs_path 
 * and its query string at query, both of which are assumed
 * to be at least of length LimitRequestLine + 1.
 */

bool parse(const char* line, char* abs_path, char* query)
{
    int length = strlen(line) + 1;

    //copy the line into new so we can use strsep and null over chars
    char* copyline = malloc(sizeof(char) * length);
    strncpy(copyline, line, length);

    //find token deliminated by space and repeat with NULL to use same string
    char* method = strtok(copyline, " ");
    char* request = strtok(NULL, " ");
    char* version = strtok(NULL, " ");

    //return error 405 if method is not GET, string compare method to find out
    if (strcmp(method, "GET") != 0)
    {
        error(405);
        return false;
    }

    //return error 502 if request-target does not start with /
    if (*request != '/')
    {
        error(501);
        return false;
    }

    //if there is a " in the reuest, return an error 
    if (strchr("\"", *request) != NULL)
    { 
        error(400);
        return false;
    }

    //HTTP version has to be 1.1
    if (strcmp(version, "HTTP/1.1\r\n") != 0)
    {
         error(505);
        return false;
    }

    //if there is no query, return nothing for query and copy the requst in absoulte path
    if (strchr(request, '?') == NULL)
    {
        strcpy(query, "");
        strncpy(abs_path, request, strlen(request));
    }

    //if there is a query
    else
    {
         //will store before ? as a token and after ? as the second token. see test.c
        strcpy(abs_path, strtok(request, "?"));
        strcpy(query, strtok(NULL, "?"));
    }

    //add null-terminator to the end of paths 
    //abs_path[strlen(abs_path)] = '/0';
    //query[strlen(query)] = '/0';
    strcat(abs_path, "\0");
    strcat(query, "\0");

    free(copyline);

    return true;

}