From 76086d6d7a027ddf42d86897200a53d724fb4bb7 Mon Sep 17 00:00:00 2001 From: Andrew Clayton Date: Fri, 8 Sep 2023 21:51:25 +0100 Subject: Wasm: Allow to set the HTTP response status. This commit enables WebAssembly modules to set the HTTP response status to something other than the previously hard coded '200 OK'. To do this they can make a call to nxt_wasm_set_resp_status() providing the required status code. If this function isn't called the status code defaults to '200 OK'. The WebAssembly module can also return -1 from the request_handler function as a short cut to signal a '500 Internal Server Error'. Signed-off-by: Andrew Clayton --- src/wasm/nxt_rt_wasmtime.c | 25 +++++++++++++++++++++++-- src/wasm/nxt_wasm.c | 27 +++++++++++++++++++++++---- src/wasm/nxt_wasm.h | 4 +++- 3 files changed, 49 insertions(+), 7 deletions(-) (limited to 'src/wasm') diff --git a/src/wasm/nxt_rt_wasmtime.c b/src/wasm/nxt_rt_wasmtime.c index 99786b89..7f05fae0 100644 --- a/src/wasm/nxt_rt_wasmtime.c +++ b/src/wasm/nxt_rt_wasmtime.c @@ -102,6 +102,19 @@ nxt_wasm_send_headers(void *env, wasmtime_caller_t *caller, } +static wasm_trap_t * +nxt_wasm_set_resp_status(void *env, wasmtime_caller_t *caller, + const wasmtime_val_t *args, size_t nargs, + wasmtime_val_t *results, size_t nresults) +{ + nxt_wasm_ctx_t *ctx = env; + + ctx->status = args[0].of.i32; + + return NULL; +} + + static void nxt_wasmtime_execute_hook(const nxt_wasm_ctx_t *ctx, nxt_wasm_fh_t hook) { @@ -123,8 +136,8 @@ nxt_wasmtime_execute_hook(const nxt_wasm_ctx_t *ctx, nxt_wasm_fh_t hook) } -static void -nxt_wasmtime_execute_request(const nxt_wasm_ctx_t *ctx) +static int +nxt_wasmtime_execute_request(nxt_wasm_ctx_t *ctx) { int i = 0; wasm_trap_t *trap = NULL; @@ -142,7 +155,10 @@ nxt_wasmtime_execute_request(const nxt_wasm_ctx_t *ctx) nxt_wasmtime_err_msg(error, trap, "failed to call function [->wasm_request_handler]" ); + return -1; } + + return results[0].of.i32; } @@ -183,6 +199,11 @@ nxt_wasmtime_set_function_imports(nxt_wasm_ctx_t *ctx) .func = nxt_wasm_send_headers, .params = { WASM_I32 }, .ft = NXT_WASM_FT_1_0 + }, { + .func_name = "nxt_wasm_set_resp_status", + .func = nxt_wasm_set_resp_status, + .params = { WASM_I32 }, + .ft = NXT_WASM_FT_1_0 }, { } diff --git a/src/wasm/nxt_wasm.c b/src/wasm/nxt_wasm.c index 45a40b4b..796ea847 100644 --- a/src/wasm/nxt_wasm.c +++ b/src/wasm/nxt_wasm.c @@ -24,6 +24,11 @@ static nxt_wasm_ctx_t nxt_wasm_ctx; static const nxt_wasm_operations_t *nxt_wops; +enum { + NXT_WASM_HTTP_OK = 200, + NXT_WASM_HTTP_ERROR = 500 +}; + void nxt_wasm_do_response_end(nxt_wasm_ctx_t *ctx) @@ -48,7 +53,7 @@ nxt_wasm_do_send_headers(nxt_wasm_ctx_t *ctx, uint32_t offset) fields_len += rh->fields[i].name_len + rh->fields[i].value_len; } - nxt_unit_response_init(ctx->req, 200, rh->nfields, fields_len); + nxt_unit_response_init(ctx->req, ctx->status, rh->nfields, fields_len); for (i = 0; i < rh->nfields; i++) { const char *name; @@ -72,7 +77,7 @@ nxt_wasm_do_send_response(nxt_wasm_ctx_t *ctx, uint32_t offset) nxt_unit_request_info_t *req = ctx->req; if (!nxt_unit_response_is_init(req)) { - nxt_unit_response_init(req, 200, 0, 0); + nxt_unit_response_init(req, ctx->status, 0, 0); } resp = (nxt_wasm_response_t *)(nxt_wasm_ctx.baddr + offset); @@ -84,6 +89,7 @@ nxt_wasm_do_send_response(nxt_wasm_ctx_t *ctx, uint32_t offset) static void nxt_wasm_request_handler(nxt_unit_request_info_t *req) { + int err; size_t offset, read_bytes, content_sent, content_len; ssize_t bytes_read; nxt_unit_field_t *sf, *sf_end; @@ -149,8 +155,12 @@ nxt_wasm_request_handler(nxt_unit_request_info_t *req) wr->request_size = offset + bytes_read; + nxt_wasm_ctx.status = NXT_WASM_HTTP_OK; nxt_wasm_ctx.req = req; - nxt_wops->exec_request(&nxt_wasm_ctx); + err = nxt_wops->exec_request(&nxt_wasm_ctx); + if (err) { + goto out_err_500; + } if (content_len == content_sent) { goto request_done; @@ -168,9 +178,18 @@ nxt_wasm_request_handler(nxt_unit_request_info_t *req) wr->request_size = wr->content_sent = bytes_read; wr->total_content_sent = content_sent; - nxt_wops->exec_request(&nxt_wasm_ctx); + err = nxt_wops->exec_request(&nxt_wasm_ctx); + if (err) { + goto out_err_500; + } } while (content_sent < content_len); + goto request_done; + +out_err_500: + nxt_unit_response_init(req, NXT_WASM_HTTP_ERROR, 0, 0); + nxt_unit_request_done(req, NXT_UNIT_OK); + request_done: NXT_WASM_DO_HOOK(NXT_WASM_FH_REQUEST_END); } diff --git a/src/wasm/nxt_wasm.h b/src/wasm/nxt_wasm.h index cb9dbdfe..2748d764 100644 --- a/src/wasm/nxt_wasm.h +++ b/src/wasm/nxt_wasm.h @@ -118,12 +118,14 @@ struct nxt_wasm_ctx_s { size_t baddr_off; size_t response_off; + + uint16_t status; }; struct nxt_wasm_operations_s { int (*init)(nxt_wasm_ctx_t *ctx); void (*destroy)(const nxt_wasm_ctx_t *ctx); - void (*exec_request)(const nxt_wasm_ctx_t *ctx); + int (*exec_request)(nxt_wasm_ctx_t *ctx); void (*exec_hook)(const nxt_wasm_ctx_t *ctx, nxt_wasm_fh_t hook); }; -- cgit From d5efa5f11f38d4ca6c64374f848055611d4f315c Mon Sep 17 00:00:00 2001 From: Andrew Clayton Date: Thu, 14 Sep 2023 00:37:28 +0100 Subject: Wasm: Fix multiple successive calls to the request_handler. When trying to upload files to the luw-upload-reflector demo[0] above a certain size that would mean Unit would need to make more than two calls to the request_handler function in the Wasm module we would get the following error from wasmtime and the upload would stall on the third call to the request_handler WASMTIME ERROR: failed to call function [->wasm_request_handler] error while executing at wasm backtrace: 0: 0x5ce2 - !memcpy 1: 0x7df - luw_req_buf_append at /home/andrew/src/unit-wasm/src/c/libunit-wasm.c:308:14 2: 0x3a1 - luw_request_handler at /home/andrew/src/unit-wasm/examples/c/luw-upload-reflector.c:110:3 Caused by: wasm trap: out of bounds memory access This was due to ->content_off (the offset of where the actual body content starts in the request structure/memory) being some overly large value. This was largely down to me being an idiot! Before calling the loop that makes the calls to the request_handler we would calculate the new offset, which is now just the size of the request structure as we don't re-send all the HTTP meta data and headers etc. However because this value is in the request structure which is in the shared memory and we use this same memory for requests and responses, when we make a response we overwrite this request structure with the response structure, so our ->content_off is now some wacked out value when we make the next call to the request_handler. To fix this we just need to reset ->content_off each time round the loop. There's also no point in setting ->nfields to 0, it has the same issue as above, but doesn't get re-used by the Wasm module anyway. [0]: Signed-off-by: Andrew Clayton --- src/wasm/nxt_wasm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/wasm') diff --git a/src/wasm/nxt_wasm.c b/src/wasm/nxt_wasm.c index 796ea847..92ed57ab 100644 --- a/src/wasm/nxt_wasm.c +++ b/src/wasm/nxt_wasm.c @@ -166,8 +166,7 @@ nxt_wasm_request_handler(nxt_unit_request_info_t *req) goto request_done; } - wr->nfields = 0; - wr->content_off = offset = sizeof(nxt_wasm_request_t); + offset = sizeof(nxt_wasm_request_t); do { read_bytes = nxt_min(content_len - content_sent, NXT_WASM_MEM_SIZE - offset); @@ -177,6 +176,7 @@ nxt_wasm_request_handler(nxt_unit_request_info_t *req) content_sent += bytes_read; wr->request_size = wr->content_sent = bytes_read; wr->total_content_sent = content_sent; + wr->content_off = offset; err = nxt_wops->exec_request(&nxt_wasm_ctx); if (err) { -- cgit From 0f630c3f604e76de370529907b51ad29dfdc4ecb Mon Sep 17 00:00:00 2001 From: Andrew Clayton Date: Thu, 14 Sep 2023 20:35:15 +0100 Subject: Wasm: Allow uploads larger than 4GiB. Currently Wasm modules are limited to a 32bit address space (until at least the memory64 work is completed). All the counters etc in the request structure were u32's. Which matched with 32bit memory limitation. However there is really no need to not allow >4GiB uploads that can be saved off to disk or some such. To do this we just need to increase the ->content_len & ->total_content_sent members to u64's. However because we need the request structure to have the exact same layout on 32bit (for Wasm modules) as it does on 64bit we need to re-jig the order of some of these members and add a four-byte padding member. Thus the request structure now looks like on 64bit (as shown by pahole(1)) struct nxt_wasm_request_s { uint32_t method_off; /* 0 4 */ uint32_t method_len; /* 4 4 */ uint32_t version_off; /* 8 4 */ uint32_t version_len; /* 12 4 */ uint32_t path_off; /* 16 4 */ uint32_t path_len; /* 20 4 */ uint32_t query_off; /* 24 4 */ uint32_t query_len; /* 28 4 */ uint32_t remote_off; /* 32 4 */ uint32_t remote_len; /* 36 4 */ uint32_t local_addr_off; /* 40 4 */ uint32_t local_addr_len; /* 44 4 */ uint32_t local_port_off; /* 48 4 */ uint32_t local_port_len; /* 52 4 */ uint32_t server_name_off; /* 56 4 */ uint32_t server_name_len; /* 60 4 */ /* --- cacheline 1 boundary (64 bytes) --- */ uint64_t content_len; /* 64 8 */ uint64_t total_content_sent; /* 72 8 */ uint32_t content_sent; /* 80 4 */ uint32_t content_off; /* 84 4 */ uint32_t request_size; /* 88 4 */ uint32_t nfields; /* 92 4 */ uint32_t tls; /* 96 4 */ char __pad[4]; /* 100 4 */ nxt_wasm_http_field_t fields[]; /* 104 0 */ /* size: 104, cachelines: 2, members: 25 */ /* last cacheline: 40 bytes */ }; and the same structure (taken from unit-wasm) compiled as 32bit struct luw_req { u32 method_off; /* 0 4 */ u32 method_len; /* 4 4 */ u32 version_off; /* 8 4 */ u32 version_len; /* 12 4 */ u32 path_off; /* 16 4 */ u32 path_len; /* 20 4 */ u32 query_off; /* 24 4 */ u32 query_len; /* 28 4 */ u32 remote_off; /* 32 4 */ u32 remote_len; /* 36 4 */ u32 local_addr_off; /* 40 4 */ u32 local_addr_len; /* 44 4 */ u32 local_port_off; /* 48 4 */ u32 local_port_len; /* 52 4 */ u32 server_name_off; /* 56 4 */ u32 server_name_len; /* 60 4 */ /* --- cacheline 1 boundary (64 bytes) --- */ u64 content_len; /* 64 8 */ u64 total_content_sent; /* 72 8 */ u32 content_sent; /* 80 4 */ u32 content_off; /* 84 4 */ u32 request_size; /* 88 4 */ u32 nr_fields; /* 92 4 */ u32 tls; /* 96 4 */ char __pad[4]; /* 100 4 */ struct luw_hdr_field fields[]; /* 104 0 */ /* size: 104, cachelines: 2, members: 25 */ /* last cacheline: 40 bytes */ }; We can see the structures have the same layout, same size and no padding. We need the __pad member as otherwise I saw gcc and clang on Alpine Linux automatically add the 'packed' attribute to the structure which made the two structures not match. Link: Link: Signed-off-by: Andrew Clayton --- src/wasm/nxt_wasm.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'src/wasm') diff --git a/src/wasm/nxt_wasm.h b/src/wasm/nxt_wasm.h index 2748d764..f78aef13 100644 --- a/src/wasm/nxt_wasm.h +++ b/src/wasm/nxt_wasm.h @@ -59,10 +59,10 @@ struct nxt_wasm_request_s { uint32_t server_name_off; uint32_t server_name_len; - uint32_t content_off; - uint32_t content_len; + uint64_t content_len; + uint64_t total_content_sent; uint32_t content_sent; - uint32_t total_content_sent; + uint32_t content_off; uint32_t request_size; @@ -70,6 +70,8 @@ struct nxt_wasm_request_s { uint32_t tls; + char __pad[4]; + nxt_wasm_http_field_t fields[]; }; -- cgit From 01d185cb52af8879aeeab04765eff439feec664c Mon Sep 17 00:00:00 2001 From: Andrew Clayton Date: Wed, 27 Sep 2023 21:25:09 +0100 Subject: Wasm: Re-add a removed 'const' qualifier in nxt_rt_wasmtime.c. This was inadvertently removed in 76086d6d ("Wasm: Allow to set the HTTP response status.") Fixes: 76086d6d ("Wasm: Allow to set the HTTP response status.") Signed-off-by: Andrew Clayton --- src/wasm/nxt_rt_wasmtime.c | 2 +- src/wasm/nxt_wasm.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'src/wasm') diff --git a/src/wasm/nxt_rt_wasmtime.c b/src/wasm/nxt_rt_wasmtime.c index 7f05fae0..bf0b0a0f 100644 --- a/src/wasm/nxt_rt_wasmtime.c +++ b/src/wasm/nxt_rt_wasmtime.c @@ -137,7 +137,7 @@ nxt_wasmtime_execute_hook(const nxt_wasm_ctx_t *ctx, nxt_wasm_fh_t hook) static int -nxt_wasmtime_execute_request(nxt_wasm_ctx_t *ctx) +nxt_wasmtime_execute_request(const nxt_wasm_ctx_t *ctx) { int i = 0; wasm_trap_t *trap = NULL; diff --git a/src/wasm/nxt_wasm.h b/src/wasm/nxt_wasm.h index f78aef13..6bc3ae35 100644 --- a/src/wasm/nxt_wasm.h +++ b/src/wasm/nxt_wasm.h @@ -127,7 +127,7 @@ struct nxt_wasm_ctx_s { struct nxt_wasm_operations_s { int (*init)(nxt_wasm_ctx_t *ctx); void (*destroy)(const nxt_wasm_ctx_t *ctx); - int (*exec_request)(nxt_wasm_ctx_t *ctx); + int (*exec_request)(const nxt_wasm_ctx_t *ctx); void (*exec_hook)(const nxt_wasm_ctx_t *ctx, nxt_wasm_fh_t hook); }; -- cgit