Marton Balint (12020-07-29):
> Thanks for working on this. I agree that proper (as RFC compliant as it can
> be) URL parsing is needed here. Probably we should clearly document
> differences from RFC compliant parsing, if we cannot do it entirely RFC
> compliantly...
Indeed. Unfortunately, that may cause some trouble, but not for right
now.
> ? and # can also separate authority from the rest.
Thanks, fixed.
> I am not sure about this approach, the known characters at the end or at the
> start will make further operations a bit harder. I'd just simply add another
> field for each URL component to signal the end, e.g.
I considered this, but it was not actually convenient.
I have something that works, but it needs polishing and more testing.
But you can have a peek.
Regards,
--
Nicolas George
>From d6c429e879ffe3cdce0af6d22854dbbcce6c8222 Mon Sep 17 00:00:00 2001
From: Nicolas George <geo...@nsup.org>
Date: Thu, 30 Jul 2020 00:02:10 +0200
Subject: [PATCH] WIP lavf/url: rewrite ff_make_absolute_url().
Signed-off-by: Nicolas George <geo...@nsup.org>
---
libavformat/url.c | 223 +++++++++++++++++++---------------------------
libavformat/url.h | 4 +-
2 files changed, 96 insertions(+), 131 deletions(-)
diff --git a/libavformat/url.c b/libavformat/url.c
index 26aaab4019..fa265e90ea 100644
--- a/libavformat/url.c
+++ b/libavformat/url.c
@@ -27,6 +27,7 @@
#if CONFIG_NETWORK
#include "network.h"
#endif
+#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
/**
@@ -152,146 +153,110 @@ int ff_url_decompose(URLComponents *uc, const char *url, const char *end)
return 0;
}
-static void trim_double_dot_url(char *buf, const char *rel, int size)
+static int append_path(char *root, char *out_end, char **rout,
+ const char *in, const char *in_end)
{
- const char *p = rel;
- const char *root = rel;
- char tmp_path[MAX_URL_SIZE] = {0, };
- char *sep;
- char *node;
-
- /* Get the path root of the url which start by "://" */
- if (p && (sep = strstr(p, "://"))) {
- sep += 3;
- root = strchr(sep, '/');
- if (!root)
- return;
- }
-
- /* set new current position if the root node is changed */
- p = root;
- while (p && (node = strstr(p, ".."))) {
- av_strlcat(tmp_path, p, node - p + strlen(tmp_path));
- p = node + 3;
- sep = strrchr(tmp_path, '/');
- if (sep)
- sep[0] = '\0';
- else
- tmp_path[0] = '\0';
+ char *out = *rout;
+ const char *d, *next;
+
+ if (in < in_end && *in == '/')
+ in++; /* already taken care of */
+ while (in < in_end) {
+ d = find_delim("/", in, in_end);
+ next = d + (d < in_end && *d == '/');
+ if (d - in == 1 && in[0] == '.') {
+ /* skip */
+ } else if (out > root && /* "../" at the very beginning really means "../" */
+ d - in == 2 && in[0] == '.' && in[1] == '.') {
+ av_assert1(out[-1] == '/');
+ if (out - root > 1)
+ while (out > root && (--out)[-1] != '/');
+ } else {
+ if (out_end - out < next - in)
+ return AVERROR(ENOMEM);
+ memcpy(out, in, next - in);
+ out += next - in;
+ }
+ in = next;
}
-
- if (!av_stristart(p, "/", NULL) && root != rel)
- av_strlcat(tmp_path, "/", size);
-
- av_strlcat(tmp_path, p, size);
- /* start set buf after temp path process. */
- av_strlcpy(buf, rel, root - rel + 1);
-
- if (!av_stristart(tmp_path, "/", NULL) && root != rel)
- av_strlcat(buf, "/", size);
-
- av_strlcat(buf, tmp_path, size);
+ *rout = out;
+ return 0;
}
-void ff_make_absolute_url(char *buf, int size, const char *base,
+int ff_make_absolute_url(char *buf, int size, const char *base,
const char *rel)
{
- char *sep, *path_query;
- char *root, *p;
- char tmp_path[MAX_URL_SIZE];
-
- memset(tmp_path, 0, sizeof(tmp_path));
- /* Absolute path, relative to the current server */
- if (base && strstr(base, "://") && rel[0] == '/') {
- if (base != buf)
- av_strlcpy(buf, base, size);
- sep = strstr(buf, "://");
- if (sep) {
- /* Take scheme from base url */
- if (rel[1] == '/') {
- sep[1] = '\0';
- } else {
- /* Take scheme and host from base url */
- sep += 3;
- sep = strchr(sep, '/');
- if (sep)
- *sep = '\0';
- }
+ URLComponents ub, uc;
+ char *out, *out_end, *path;
+ const char *keep;
+ int ret;
+
+ //const char *scheme; /**< possibly including lavf-specific options */
+ //const char *authority; /**< "//" if it is a real URL */
+ //const char *userinfo; /**< including final '@' if present */
+ //const char *host;
+ //const char *port; /**< including initial ':' if present */
+ //const char *path;
+ //const char *query; /**< including initial '?' if present */
+ //const char *fragment; /**< including initial '#' if present */
+ //const char *end;
+
+ if (!size)
+ return AVERROR(ENOMEM);
+ out = buf;
+ out_end = buf + size - 1;
+
+ if ((ret = ff_url_decompose(&ub, base, NULL) < 0) ||
+ (ret = ff_url_decompose(&uc, rel, NULL) < 0))
+ return ret;
+
+ keep = ub.url;
+#define KEEP(component) \
+ if (uc.url_component_end_##component == uc.url) \
+ keep = ub.url_component_end_##component
+ KEEP(scheme);
+ KEEP(authority_full);
+ KEEP(path);
+ KEEP(query);
+ KEEP(fragment);
+#undef KEEP
+#define COPY(start, end) do { \
+ size_t len = end - start; \
+ if (len > out_end - out) \
+ return AVERROR(ENOMEM); \
+ memcpy(out, start, len); \
+ out += len; \
+ } while (0);
+ COPY(ub.url, keep);
+ COPY(uc.url, uc.path);
+
+ if (uc.url_component_end_path > uc.url) {
+ path = out;
+ if (ub.url_component_end_authority > ub.authority ||
+ uc.url_component_end_authority > uc.authority ||
+ (ub.url_component_end_path > ub.path && ub.path[0] == '/') ||
+ (uc.url_component_end_path > uc.path && uc.path[1] == '/')) {
+ const char *root = "/";
+ COPY(root, root + 1);
}
- av_strlcat(buf, rel, size);
- trim_double_dot_url(tmp_path, buf, size);
- memset(buf, 0, size);
- av_strlcpy(buf, tmp_path, size);
- return;
- }
- /* If rel actually is an absolute url, just copy it */
- if (!base || strstr(rel, "://") || rel[0] == '/') {
- memset(buf, 0, size);
- trim_double_dot_url(buf, rel, size);
- return;
- }
- if (base != buf)
- av_strlcpy(buf, base, size);
-
- /* Strip off any query string from base */
- path_query = strchr(buf, '?');
- if (path_query)
- *path_query = '\0';
-
- /* Is relative path just a new query part? */
- if (rel[0] == '?') {
- av_strlcat(buf, rel, size);
- trim_double_dot_url(tmp_path, buf, size);
- memset(buf, 0, size);
- av_strlcpy(buf, tmp_path, size);
- return;
- }
-
- root = p = buf;
- /* Get the path root of the url which start by "://" */
- if (p && strstr(p, "://")) {
- sep = strstr(p, "://");
- if (sep) {
- sep += 3;
- root = strchr(sep, '/');
- if (!root)
- return;
+ if (uc.url_component_end_path > uc.path) {
+ const char *base_path_end = ub.path;
+ if (uc.path[0] != '/') {
+ base_path_end = ub.url_component_end_path;
+ while (base_path_end > ub.path && base_path_end[-1] != '/')
+ base_path_end--;
+ }
+ if ((ret = append_path(path, out_end, &out, ub.path, base_path_end)) < 0 ||
+ (ret = append_path(path, out_end, &out, uc.path, uc.url_component_end_path)) < 0)
+ return ret;
}
}
- /* Remove the file name from the base url */
- sep = strrchr(buf, '/');
- if (sep && sep <= root)
- sep = root;
-
- if (sep)
- sep[1] = '\0';
- else
- buf[0] = '\0';
- while (av_strstart(rel, "..", NULL) && sep) {
- /* Remove the path delimiter at the end */
- if (sep > root) {
- sep[0] = '\0';
- sep = strrchr(buf, '/');
- }
+ COPY(uc.url_component_end_path, uc.end);
- /* If the next directory name to pop off is "..", break here */
- if (!strcmp(sep ? &sep[1] : buf, "..")) {
- /* Readd the slash we just removed */
- av_strlcat(buf, "/", size);
- break;
- }
- /* Cut off the directory name */
- if (sep)
- sep[1] = '\0';
- else
- buf[0] = '\0';
- rel += 3;
- }
- av_strlcat(buf, rel, size);
- trim_double_dot_url(tmp_path, buf, size);
- memset(buf, 0, size);
- av_strlcpy(buf, tmp_path, size);
+#undef COPY
+ *out = 0;
+ return 0;
}
AVIODirEntry *ff_alloc_dir_entry(void)
diff --git a/libavformat/url.h b/libavformat/url.h
index 4866080e70..bbea485432 100644
--- a/libavformat/url.h
+++ b/libavformat/url.h
@@ -312,8 +312,8 @@ int ff_url_join(char *str, int size, const char *proto,
* @param base the base url, may be equal to buf.
* @param rel the new url, which is interpreted relative to base
*/
-void ff_make_absolute_url(char *buf, int size, const char *base,
- const char *rel);
+int ff_make_absolute_url(char *buf, int size, const char *base,
+ const char *rel);
/**
* Allocate directory entry with default values.
--
2.27.0
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