C memory management in server application

Question

I am student and I am writing HTTP proxy application in C. I have trouble with memory management. In all my previous applications I simply wrote a wrapper around malloc which aborted when malloc failed.

void *xmalloc(size_t size)
{
    void *ptr;

    assert(size);

    ptr = malloc(size);
    if (!ptr) 
        abort();

    return ptr;
}

This I now find insufficient as I just want to refuse client and continue serving other clients when memory allocation fails due to temporary shortage of memory. If I don't want to clutter my code with checks after each malloc call (I have quite lot of them per function in parsing code), what are other options to handle memory management and which one is the best for my purposes and how what is a common way for server applications to handle memory management and shortage of memory?

Consider this function from my current code which parses one line from header portion of HTTP message (xstrndup calls xmalloc):

int http_header_parse(http_hdr_table *t, const char *s)
{
    const char *p;
    const char *b;
    char *tmp_name;
    char *tmp_value;
    int ret = -1;

    assert(t);
    assert(s);

    p = b = s;

    /* field name */
    for (; ; p++) {
        if (*p == ':') {
            if (p-b <= 0) goto out;
            tmp_name = xstrndup(b, p-b);
            b = ++p;
            break;
        }

        if (is_ctl_char(*p) || is_sep_char(*p)) goto out;
    }

    while (*p == ' ' || *p == '\t') {
        p++; b++;
    }

    /* field value */
    for (; ; p++) {
        if (is_crlf(p)) {
            if (p-b <= 0) goto err_value;
            tmp_value = xstrndup(b, p-b);
            p += 2;
            break;
        }

        if (!*p) goto err_value;
    }
    http_hdr_table_set(t, tmp_name, tmp_value);

    ret = 0;
    xfree(tmp_value);
err_value:
    xfree(tmp_name);
out:
    return ret;
}

I would like to keep things simple and handle memory allocation errors at one place and to not clutter code with malloc error handling code. What should I do? Thank you.

P.S: I am writing the application to run on POSIX/Unix-like systems. Also feel free to criticize my current coding style and practices.

Answer 1

If you want to use a relatively low level language like C, then you shouldn't be too worried about adding something like if(tmp_value == NULL) goto out; in 2 places.

If you can't stand the idea of 2 trivial lines of extra code, then maybe try a language that supports exceptions properly (e.g. C++) and add throw/try/catch instead. Note: I really don't like C++, but using C++ would have to make more sense than implementing your own "exception like" features and an entire layer of automated resource de-allocation in C.