Hi Yifan,

On 2025/11/20 17:22, Yifan Zhao wrote:
This patch introduces support for AWS Signature Version 4 for s3erofs
remote backend.

Now users can specify the folowing options:
  - passwd_file=Y, S3 credentials file in the format $ak:$sk (optional);
  - urlstyle=<vhost, path>, S3 API calling style (optional);
  - sig=<2,4>, S3 API signature version (optional);
  - region=W, region code for S3 endpoint (required for sig=4).

e.g.:
mkfs.erofs \
     --s3=s3.us-east-1.amazonaws.com,sig=4,region=us-east-1 \
     output.img some_bucket/path/to/object

Thanks for the effort!

Could we find a public s3 bucket and post here as an example?


Signed-off-by: Yifan Zhao <[email protected]>
---
  lib/liberofs_s3.h |   1 +
  lib/remotes/s3.c  | 567 +++++++++++++++++++++++++++++++++++++---------
  mkfs/main.c       |  14 +-
  3 files changed, 471 insertions(+), 111 deletions(-)

diff --git a/lib/liberofs_s3.h b/lib/liberofs_s3.h
index f2ec822..f4886cd 100644
--- a/lib/liberofs_s3.h
+++ b/lib/liberofs_s3.h
@@ -27,6 +27,7 @@ enum s3erofs_signature_version {
  struct erofs_s3 {
        void *easy_curl;
        const char *endpoint;
+       const char *region;
        char access_key[S3_ACCESS_KEY_LEN + 1];
        char secret_key[S3_SECRET_KEY_LEN + 1];
diff --git a/lib/remotes/s3.c b/lib/remotes/s3.c
index 0f7e1a9..3263dd7 100644
--- a/lib/remotes/s3.c
+++ b/lib/remotes/s3.c
@@ -23,7 +23,8 @@
  #define S3EROFS_PATH_MAX              1024
  #define S3EROFS_MAX_QUERY_PARAMS      16
  #define S3EROFS_URL_LEN                       8192
-#define S3EROFS_CANONICAL_QUERY_LEN    2048
+#define S3EROFS_CANONICAL_URI_LEN      1024

Is there a spec to document that?

+#define S3EROFS_CANONICAL_QUERY_LEN    S3EROFS_URL_LEN
#define BASE64_ENCODE_LEN(len) (((len + 2) / 3) * 4) @@ -34,52 +35,142 @@ struct s3erofs_query_params {
  };
struct s3erofs_curl_request {
-       const char *method;

It seems it's removed... S3 only allows `GET` method?

        char url[S3EROFS_URL_LEN];
+       char canonical_uri[S3EROFS_CANONICAL_URI_LEN];
        char canonical_query[S3EROFS_CANONICAL_QUERY_LEN];
  };
+static const char *s3erofs_parse_host(const char *endpoint, const char **schema) {

K&R style is:

static const char *s3erofs_parse_host()
{
        if (!tmp) {
                ...
        } else {
                ...
        }

}

+       const char *tmp = strstr(endpoint, "://");
+       const char *host;
+
+       if (!tmp) {
+               host = endpoint;
+               if (schema)
+                       *schema = NULL;
+       } else {
+               host = tmp + sizeof("://") - 1;
+               if (schema) {
+                       *schema = strndup(endpoint, host - endpoint);
+                       if (!*schema)
+                               return ERR_PTR(-ENOMEM);
+               }
+       }
+
+       return host;
+}
+
+static int s3erofs_urlencode(const char *input, char **output)
+{

static void *s3erofs_urlencode(const char *input)
{
        char *output;

        output = malloc(strlen(input) * 3 + 1);
        if (!output)
                return ERR_PTR(-ENOMEM);

        ...

        return output;

}

+       static const char hex[] = "0123456789ABCDEF";
+       int i;
+       char c, *p;
+
+       *output = malloc(strlen(input) * 3 + 1);
+       if (!*output)
+               return -ENOMEM;
+
+       p = *output;
+       for (i = 0; i < strlen(input); ++i) {
+               c = (unsigned char)input[i];
+
+               // Unreserved characters: A-Z a-z 0-9 - . _ ~
+               if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') ||
+                   (c >= '0' && c <= '9') || c == '-' || c == '.' || c == '_' 
||
+                   c == '~') {
+                       *p++ = c;
+               } else {
+                       *p++ = '%';
+                       *p++ = hex[c >> 4];
+                       *p++ = hex[c & 0x0F];
+               }
+       }
+       *p = '\0';
+
+       return 0;
+}
+
+struct kv_pair {
+       char *key;
+       char *value;
+};
+
+static int compare_kv_pair(const void *a, const void *b)
+{
+       return strcmp(((const struct kv_pair *)a)->key, ((const struct kv_pair 
*)b)->key);
+}
+
+static int s3erofs_prepare_canonical_query(struct s3erofs_curl_request *req,
+                                          struct s3erofs_query_params *params)
+{
+       struct kv_pair *pairs;
+       int i, pos = 0, ret = 0;
+
+       if (params->num == 0)

        if (!params->num) {
        }

+               return 0;
+
+       pairs = malloc(sizeof(struct kv_pair) * params->num);
+       for (i = 0; i < params->num; i++) {
+               ret = s3erofs_urlencode(params->key[i], &pairs[i].key);
+               if (ret < 0)
+                       goto out;
+               ret = s3erofs_urlencode(params->value[i], &pairs[i].value);

Why we use urlencoding now?

Thanks,
Gao Xiang

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