From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS24961 89.163.224.0/20 X-Spam-Status: No, score=0.3 required=3.0 tests=BAYES_00,RCVD_IN_MSPIKE_BL, RCVD_IN_MSPIKE_ZBI,RCVD_IN_XBL,SPF_FAIL,SPF_HELO_FAIL,TO_EQ_FM_DOM_SPF_FAIL shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from 80x24.org (tor1.mysec-arch.net [89.163.237.45]) by dcvr.yhbt.net (Postfix) with ESMTP id 839C5203E1 for ; Fri, 22 Jul 2016 03:40:53 +0000 (UTC) From: Eric Wong To: spew@80x24.org Subject: [PATCH] http-backend: buffer headers before sending Date: Fri, 22 Jul 2016 03:40:49 +0000 Message-Id: <20160722034049.25044-1-e@80x24.org> List-Id: Avoid waking up the readers for unnecessary context switches for each line of header data being written. Tested by strace-ing the response parsing on the CGI side. --- http-backend.c | 220 ++++++++++++++++++++++++++++++--------------------------- 1 file changed, 116 insertions(+), 104 deletions(-) diff --git a/http-backend.c b/http-backend.c index 0d59499..adc8c8c 100644 --- a/http-backend.c +++ b/http-backend.c @@ -75,55 +75,57 @@ static void format_write(int fd, const char *fmt, ...) write_or_die(fd, buffer, n); } -static void http_status(unsigned code, const char *msg) +static void http_status(struct strbuf *hdr, unsigned code, const char *msg) { - format_write(1, "Status: %u %s\r\n", code, msg); + strbuf_addf(hdr, "Status: %u %s\r\n", code, msg); } -static void hdr_str(const char *name, const char *value) +static void hdr_str(struct strbuf *hdr, const char *name, const char *value) { - format_write(1, "%s: %s\r\n", name, value); + strbuf_addf(hdr, "%s: %s\r\n", name, value); } -static void hdr_int(const char *name, uintmax_t value) +static void hdr_int(struct strbuf *hdr, const char *name, uintmax_t value) { - format_write(1, "%s: %" PRIuMAX "\r\n", name, value); + strbuf_addf(hdr, "%s: %" PRIuMAX "\r\n", name, value); } -static void hdr_date(const char *name, unsigned long when) +static void hdr_date(struct strbuf *hdr, const char *name, unsigned long when) { const char *value = show_date(when, 0, DATE_MODE(RFC2822)); - hdr_str(name, value); + hdr_str(hdr, name, value); } -static void hdr_nocache(void) +static void hdr_nocache(struct strbuf *hdr) { - hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT"); - hdr_str("Pragma", "no-cache"); - hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate"); + hdr_str(hdr, "Expires", "Fri, 01 Jan 1980 00:00:00 GMT"); + hdr_str(hdr, "Pragma", "no-cache"); + hdr_str(hdr, "Cache-Control", "no-cache, max-age=0, must-revalidate"); } -static void hdr_cache_forever(void) +static void hdr_cache_forever(struct strbuf *hdr) { unsigned long now = time(NULL); - hdr_date("Date", now); - hdr_date("Expires", now + 31536000); - hdr_str("Cache-Control", "public, max-age=31536000"); + hdr_date(hdr, "Date", now); + hdr_date(hdr, "Expires", now + 31536000); + hdr_str(hdr, "Cache-Control", "public, max-age=31536000"); } -static void end_headers(void) +static void end_headers(struct strbuf *hdr) { - write_or_die(1, "\r\n", 2); + strbuf_add(hdr, "\r\n", 2); + write_or_die(1, hdr->buf, hdr->len); + strbuf_release(hdr); } -__attribute__((format (printf, 1, 2))) -static NORETURN void not_found(const char *err, ...) +__attribute__((format (printf, 2, 3))) +static NORETURN void not_found(struct strbuf *hdr, const char *err, ...) { va_list params; - http_status(404, "Not Found"); - hdr_nocache(); - end_headers(); + http_status(hdr, 404, "Not Found"); + hdr_nocache(hdr); + end_headers(hdr); va_start(params, err); if (err && *err) @@ -132,14 +134,14 @@ static NORETURN void not_found(const char *err, ...) exit(0); } -__attribute__((format (printf, 1, 2))) -static NORETURN void forbidden(const char *err, ...) +__attribute__((format (printf, 2, 3))) +static NORETURN void forbidden(struct strbuf *hdr, const char *err, ...) { va_list params; - http_status(403, "Forbidden"); - hdr_nocache(); - end_headers(); + http_status(hdr, 403, "Forbidden"); + hdr_nocache(hdr); + end_headers(hdr); va_start(params, err); if (err && *err) @@ -148,21 +150,23 @@ static NORETURN void forbidden(const char *err, ...) exit(0); } -static void select_getanyfile(void) +static void select_getanyfile(struct strbuf *hdr) { if (!getanyfile) - forbidden("Unsupported service: getanyfile"); + forbidden(hdr, "Unsupported service: getanyfile"); } -static void send_strbuf(const char *type, struct strbuf *buf) +static void send_strbuf(struct strbuf *hdr, + const char *type, struct strbuf *buf) { - hdr_int(content_length, buf->len); - hdr_str(content_type, type); - end_headers(); + hdr_int(hdr, content_length, buf->len); + hdr_str(hdr, content_type, type); + end_headers(hdr); write_or_die(1, buf->buf, buf->len); } -static void send_local_file(const char *the_type, const char *name) +static void send_local_file(struct strbuf *hdr, const char *the_type, + const char *name) { char *p = git_pathdup("%s", name); size_t buf_alloc = 8192; @@ -172,14 +176,14 @@ static void send_local_file(const char *the_type, const char *name) fd = open(p, O_RDONLY); if (fd < 0) - not_found("Cannot open '%s': %s", p, strerror(errno)); + not_found(hdr, "Cannot open '%s': %s", p, strerror(errno)); if (fstat(fd, &sb) < 0) die_errno("Cannot stat '%s'", p); - hdr_int(content_length, sb.st_size); - hdr_str(content_type, the_type); - hdr_date(last_modified, sb.st_mtime); - end_headers(); + hdr_int(hdr, content_length, sb.st_size); + hdr_str(hdr, content_type, the_type); + hdr_date(hdr, last_modified, sb.st_mtime); + end_headers(hdr); for (;;) { ssize_t n = xread(fd, buf, buf_alloc); @@ -194,32 +198,32 @@ static void send_local_file(const char *the_type, const char *name) free(p); } -static void get_text_file(char *name) +static void get_text_file(struct strbuf *hdr, char *name) { - select_getanyfile(); - hdr_nocache(); - send_local_file("text/plain", name); + select_getanyfile(hdr); + hdr_nocache(hdr); + send_local_file(hdr, "text/plain", name); } -static void get_loose_object(char *name) +static void get_loose_object(struct strbuf *hdr, char *name) { - select_getanyfile(); - hdr_cache_forever(); - send_local_file("application/x-git-loose-object", name); + select_getanyfile(hdr); + hdr_cache_forever(hdr); + send_local_file(hdr, "application/x-git-loose-object", name); } -static void get_pack_file(char *name) +static void get_pack_file(struct strbuf *hdr, char *name) { - select_getanyfile(); - hdr_cache_forever(); - send_local_file("application/x-git-packed-objects", name); + select_getanyfile(hdr); + hdr_cache_forever(hdr); + send_local_file(hdr, "application/x-git-packed-objects", name); } -static void get_idx_file(char *name) +static void get_idx_file(struct strbuf *hdr, char *name) { - select_getanyfile(); - hdr_cache_forever(); - send_local_file("application/x-git-packed-objects-toc", name); + select_getanyfile(hdr); + hdr_cache_forever(hdr); + send_local_file(hdr, "application/x-git-packed-objects-toc", name); } static void http_config(void) @@ -241,14 +245,14 @@ static void http_config(void) strbuf_release(&var); } -static struct rpc_service *select_service(const char *name) +static struct rpc_service *select_service(struct strbuf *hdr, const char *name) { const char *svc_name; struct rpc_service *svc = NULL; int i; if (!skip_prefix(name, "git-", &svc_name)) - forbidden("Unsupported service: '%s'", name); + forbidden(hdr, "Unsupported service: '%s'", name); for (i = 0; i < ARRAY_SIZE(rpc_service); i++) { struct rpc_service *s = &rpc_service[i]; @@ -259,14 +263,14 @@ static struct rpc_service *select_service(const char *name) } if (!svc) - forbidden("Unsupported service: '%s'", name); + forbidden(hdr, "Unsupported service: '%s'", name); if (svc->enabled < 0) { const char *user = getenv("REMOTE_USER"); svc->enabled = (user && *user) ? 1 : 0; } if (!svc->enabled) - forbidden("Service not enabled: '%s'", svc->name); + forbidden(hdr, "Service not enabled: '%s'", svc->name); return svc; } @@ -442,23 +446,23 @@ static int show_text_ref(const char *name, const struct object_id *oid, return 0; } -static void get_info_refs(char *arg) +static void get_info_refs(struct strbuf *hdr, char *arg) { const char *service_name = get_parameter("service"); struct strbuf buf = STRBUF_INIT; - hdr_nocache(); + hdr_nocache(hdr); if (service_name) { const char *argv[] = {NULL /* service name */, "--stateless-rpc", "--advertise-refs", ".", NULL}; - struct rpc_service *svc = select_service(service_name); + struct rpc_service *svc = select_service(hdr, service_name); strbuf_addf(&buf, "application/x-git-%s-advertisement", svc->name); - hdr_str(content_type, buf.buf); - end_headers(); + hdr_str(hdr, content_type, buf.buf); + end_headers(hdr); packet_write(1, "# service=git-%s\n", svc->name); packet_flush(1); @@ -467,9 +471,9 @@ static void get_info_refs(char *arg) run_service(argv, 0); } else { - select_getanyfile(); + select_getanyfile(hdr); for_each_namespaced_ref(show_text_ref, &buf); - send_strbuf("text/plain", &buf); + send_strbuf(hdr, "text/plain", &buf); } strbuf_release(&buf); } @@ -494,24 +498,24 @@ static int show_head_ref(const char *refname, const struct object_id *oid, return 0; } -static void get_head(char *arg) +static void get_head(struct strbuf *hdr, char *arg) { struct strbuf buf = STRBUF_INIT; - select_getanyfile(); + select_getanyfile(hdr); head_ref_namespaced(show_head_ref, &buf); - send_strbuf("text/plain", &buf); + send_strbuf(hdr, "text/plain", &buf); strbuf_release(&buf); } -static void get_info_packs(char *arg) +static void get_info_packs(struct strbuf *hdr, char *arg) { size_t objdirlen = strlen(get_object_directory()); struct strbuf buf = STRBUF_INIT; struct packed_git *p; size_t cnt = 0; - select_getanyfile(); + select_getanyfile(hdr); prepare_packed_git(); for (p = packed_git; p; p = p->next) { if (p->pack_local) @@ -525,12 +529,12 @@ static void get_info_packs(char *arg) } strbuf_addch(&buf, '\n'); - hdr_nocache(); - send_strbuf("text/plain; charset=utf-8", &buf); + hdr_nocache(hdr); + send_strbuf(hdr, "text/plain; charset=utf-8", &buf); strbuf_release(&buf); } -static void check_content_type(const char *accepted_type) +static void check_content_type(struct strbuf *hdr, const char *accepted_type) { const char *actual_type = getenv("CONTENT_TYPE"); @@ -538,9 +542,9 @@ static void check_content_type(const char *accepted_type) actual_type = ""; if (strcmp(actual_type, accepted_type)) { - http_status(415, "Unsupported Media Type"); - hdr_nocache(); - end_headers(); + http_status(hdr, 415, "Unsupported Media Type"); + hdr_nocache(hdr); + end_headers(hdr); format_write(1, "Expected POST with Content-Type '%s'," " but received '%s' instead.\n", @@ -549,23 +553,23 @@ static void check_content_type(const char *accepted_type) } } -static void service_rpc(char *service_name) +static void service_rpc(struct strbuf *hdr, char *service_name) { const char *argv[] = {NULL, "--stateless-rpc", ".", NULL}; - struct rpc_service *svc = select_service(service_name); + struct rpc_service *svc = select_service(hdr, service_name); struct strbuf buf = STRBUF_INIT; strbuf_reset(&buf); strbuf_addf(&buf, "application/x-git-%s-request", svc->name); - check_content_type(buf.buf); + check_content_type(hdr, buf.buf); - hdr_nocache(); + hdr_nocache(hdr); strbuf_reset(&buf); strbuf_addf(&buf, "application/x-git-%s-result", svc->name); - hdr_str(content_type, buf.buf); + hdr_str(hdr, content_type, buf.buf); - end_headers(); + end_headers(hdr); argv[0] = svc->name; run_service(argv, svc->buffer_input); @@ -576,11 +580,13 @@ static int dead; static NORETURN void die_webcgi(const char *err, va_list params) { if (dead <= 1) { + struct strbuf hdr = STRBUF_INIT; + vreportf("fatal: ", err, params); - http_status(500, "Internal Server Error"); - hdr_nocache(); - end_headers(); + http_status(&hdr, 500, "Internal Server Error"); + hdr_nocache(&hdr); + end_headers(&hdr); } exit(0); /* we successfully reported a failure ;-) */ } @@ -617,7 +623,7 @@ static char* getdir(void) static struct service_cmd { const char *method; const char *pattern; - void (*imp)(char *); + void (*imp)(struct strbuf *, char *); } services[] = { {"GET", "/HEAD$", get_head}, {"GET", "/info/refs$", get_info_refs}, @@ -632,6 +638,21 @@ static struct service_cmd { {"POST", "/git-receive-pack$", service_rpc} }; +static int bad_request(struct strbuf *hdr, const struct service_cmd *c) +{ + const char *proto = getenv("SERVER_PROTOCOL"); + + if (proto && !strcmp(proto, "HTTP/1.1")) { + http_status(hdr, 405, "Method Not Allowed"); + hdr_str(hdr, "Allow", + !strcmp(c->method, "GET") ? "GET, HEAD" : c->method); + } else + http_status(hdr, 400, "Bad Request"); + hdr_nocache(hdr); + end_headers(hdr); + return 0; +} + int cmd_main(int argc, const char **argv) { char *method = getenv("REQUEST_METHOD"); @@ -639,6 +660,7 @@ int cmd_main(int argc, const char **argv) struct service_cmd *cmd = NULL; char *cmd_arg = NULL; int i; + struct strbuf hdr = STRBUF_INIT; set_die_routine(die_webcgi); set_die_is_recursing_routine(die_webcgi_recursing); @@ -659,18 +681,8 @@ int cmd_main(int argc, const char **argv) if (!regexec(&re, dir, 1, out, 0)) { size_t n; - if (strcmp(method, c->method)) { - const char *proto = getenv("SERVER_PROTOCOL"); - if (proto && !strcmp(proto, "HTTP/1.1")) { - http_status(405, "Method Not Allowed"); - hdr_str("Allow", !strcmp(c->method, "GET") ? - "GET, HEAD" : c->method); - } else - http_status(400, "Bad Request"); - hdr_nocache(); - end_headers(); - return 0; - } + if (strcmp(method, c->method)) + return bad_request(&hdr, c); cmd = c; n = out[0].rm_eo - out[0].rm_so; @@ -682,19 +694,19 @@ int cmd_main(int argc, const char **argv) } if (!cmd) - not_found("Request not supported: '%s'", dir); + not_found(&hdr, "Request not supported: '%s'", dir); setup_path(); if (!enter_repo(dir, 0)) - not_found("Not a git repository: '%s'", dir); + not_found(&hdr, "Not a git repository: '%s'", dir); if (!getenv("GIT_HTTP_EXPORT_ALL") && access("git-daemon-export-ok", F_OK) ) - not_found("Repository not exported: '%s'", dir); + not_found(&hdr, "Repository not exported: '%s'", dir); http_config(); max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER", max_request_buffer); - cmd->imp(cmd_arg); + cmd->imp(&hdr, cmd_arg); return 0; }