From 2abc22e63943371128990e4dffcf8d1f7d44c10f Mon Sep 17 00:00:00 2001 From: Michael Tokarev Date: Sat, 29 Jun 2024 16:27:00 +0300 Subject: [PATCH] block/curl: rewrite http header parsing function Existing code was long, unclear and twisty. This also relaxes the rules a tiny bit: allows to have whitespace before header name and colon and makes the header value match to be case-insensitive. Signed-off-by: Michael Tokarev Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/curl.c | 44 ++++++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 26 deletions(-) diff --git a/block/curl.c b/block/curl.c index ef5252d00b..0fdb6d39ac 100644 --- a/block/curl.c +++ b/block/curl.c @@ -210,37 +210,29 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque) { BDRVCURLState *s = opaque; size_t realsize = size * nmemb; - const char *header = (char *)ptr; - const char *end = header + realsize; - const char *accept_ranges = "accept-ranges:"; - const char *bytes = "bytes"; + const char *p = ptr; + const char *end = p + realsize; + const char *t = "accept-ranges : bytes "; /* A lowercase template */ - if (realsize >= strlen(accept_ranges) - && g_ascii_strncasecmp(header, accept_ranges, - strlen(accept_ranges)) == 0) { - - char *p = strchr(header, ':') + 1; - - /* Skip whitespace between the header name and value. */ - while (p < end && *p && g_ascii_isspace(*p)) { - p++; - } - - if (end - p >= strlen(bytes) - && strncmp(p, bytes, strlen(bytes)) == 0) { - - /* Check that there is nothing but whitespace after the value. */ - p += strlen(bytes); - while (p < end && *p && g_ascii_isspace(*p)) { - p++; - } - - if (p == end || !*p) { - s->accept_range = true; + /* check if header matches the "t" template */ + for (;;) { + if (*t == ' ') { /* space in t matches any amount of isspace in p */ + if (p < end && g_ascii_isspace(*p)) { + ++p; + } else { + ++t; } + } else if (*t && p < end && *t == g_ascii_tolower(*p)) { + ++p, ++t; + } else { + break; } } + if (!*t && p == end) { /* if we managed to reach ends of both strings */ + s->accept_range = true; + } + return realsize; }