diff --git a/http.c b/http.c index 1569c56108..5199e602be 100644 --- a/http.c +++ b/http.c @@ -904,11 +904,71 @@ static int http_request(const char *url, return ret; } +/* + * Update the "base" url to a more appropriate value, as deduced by + * redirects seen when requesting a URL starting with "url". + * + * The "asked" parameter is a URL that we asked curl to access, and must begin + * with "base". + * + * The "got" parameter is the URL that curl reported to us as where we ended + * up. + * + * Returns 1 if we updated the base url, 0 otherwise. + * + * Our basic strategy is to compare "base" and "asked" to find the bits + * specific to our request. We then strip those bits off of "got" to yield the + * new base. So for example, if our base is "http://example.com/foo.git", + * and we ask for "http://example.com/foo.git/info/refs", we might end up + * with "https://other.example.com/foo.git/info/refs". We would want the + * new URL to become "https://other.example.com/foo.git". + * + * Note that this assumes a sane redirect scheme. It's entirely possible + * in the example above to end up at a URL that does not even end in + * "info/refs". In such a case we simply punt, as there is not much we can + * do (and such a scheme is unlikely to represent a real git repository, + * which means we are likely about to abort anyway). + */ +static int update_url_from_redirect(struct strbuf *base, + const char *asked, + const struct strbuf *got) +{ + const char *tail; + size_t tail_len; + + if (!strcmp(asked, got->buf)) + return 0; + + if (prefixcmp(asked, base->buf)) + die("BUG: update_url_from_redirect: %s is not a superset of %s", + asked, base->buf); + + tail = asked + base->len; + tail_len = strlen(tail); + + if (got->len < tail_len || + strcmp(tail, got->buf + got->len - tail_len)) + return 0; /* insane redirect scheme */ + + strbuf_reset(base); + strbuf_add(base, got->buf, got->len - tail_len); + return 1; +} + static int http_request_reauth(const char *url, void *result, int target, struct http_get_options *options) { int ret = http_request(url, result, target, options); + + if (options && options->effective_url && options->base_url) { + if (update_url_from_redirect(options->base_url, + url, options->effective_url)) { + credential_from_url(&http_auth, options->base_url->buf); + url = options->effective_url->buf; + } + } + if (ret != HTTP_REAUTH) return ret; diff --git a/http.h b/http.h index 974ede7736..12ca5c892d 100644 --- a/http.h +++ b/http.h @@ -139,6 +139,14 @@ struct http_get_options { * redirects we followed. */ struct strbuf *effective_url; + + /* + * If both base_url and effective_url are non-NULL, the base URL will + * be munged to reflect any redirections going from the requested url + * to effective_url. See the definition of update_url_from_redirect + * for details. + */ + struct strbuf *base_url; }; /* Return values for http_get_*() */