Git-aware CGI to provide dumb HTTP transport
The git-http-backend CGI can be configured into any Apache server using ScriptAlias, such as with the following configuration: LoadModule cgi_module /usr/libexec/apache2/mod_cgi.so LoadModule alias_module /usr/libexec/apache2/mod_alias.so ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/ Repositories are accessed via the translated PATH_INFO. The CGI is backwards compatible with the dumb client, allowing all older HTTP clients to continue to download repositories which are managed by the CGI. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>maint
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				|  | @ -55,6 +55,7 @@ git-get-tar-commit-id | |||
| git-grep | ||||
| git-hash-object | ||||
| git-help | ||||
| git-http-backend | ||||
| git-http-fetch | ||||
| git-http-push | ||||
| git-imap-send | ||||
|  |  | |||
|  | @ -0,0 +1,105 @@ | |||
| git-http-backend(1) | ||||
| =================== | ||||
|  | ||||
| NAME | ||||
| ---- | ||||
| git-http-backend - Server side implementation of Git over HTTP | ||||
|  | ||||
| SYNOPSIS | ||||
| -------- | ||||
| [verse] | ||||
| 'git-http-backend' | ||||
|  | ||||
| DESCRIPTION | ||||
| ----------- | ||||
| A simple CGI program to serve the contents of a Git repository to Git | ||||
| clients accessing the repository over http:// and https:// protocols. | ||||
|  | ||||
| By default, only the `upload-pack` service is enabled, which serves | ||||
| 'git-fetch-pack' and 'git-ls-remote' clients, which are invoked from | ||||
| 'git-fetch', 'git-pull', and 'git-clone'. | ||||
|  | ||||
| This is ideally suited for read-only updates, i.e., pulling from | ||||
| git repositories. | ||||
|  | ||||
| URL TRANSLATION | ||||
| --------------- | ||||
| 'git-http-backend' relies on the invoking web server to perform | ||||
| URL to path translation, and store the repository path into the | ||||
| PATH_TRANSLATED environment variable.  Most web servers will do | ||||
| this translation automatically, resolving the suffix after the | ||||
| CGI name relative to the server's document root. | ||||
|  | ||||
| EXAMPLES | ||||
| -------- | ||||
|  | ||||
| Apache 2.x:: | ||||
| 	To serve all Git repositories contained within the '/git/' | ||||
| 	subdirectory of the DocumentRoot, ensure mod_cgi and | ||||
| 	mod_alias are enabled, and create a ScriptAlias to the CGI: | ||||
| + | ||||
| ---------------------------------------------------------------- | ||||
| ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/git/ | ||||
|  | ||||
| <Directory /usr/libexec/git-core> | ||||
| 	Options None | ||||
| </Directory> | ||||
| <Files /usr/libexec/git-core/git-http-backend> | ||||
| 	Options ExecCGI | ||||
| </Files> | ||||
| ---------------------------------------------------------------- | ||||
| + | ||||
| To require authentication for reads, use a Directory | ||||
| directive around the repository, or one of its parent directories: | ||||
| + | ||||
| ---------------------------------------------------------------- | ||||
| <Directory /var/www/git/private> | ||||
| 	AuthType Basic | ||||
| 	AuthName "Private Git Access" | ||||
| 	Require group committers | ||||
| 	... | ||||
| </Directory> | ||||
| ---------------------------------------------------------------- | ||||
|  | ||||
| Accelerated static Apache 2.x:: | ||||
| 	Similar to the above, but Apache can be used to return static | ||||
| 	files that are stored on disk.	On many systems this may | ||||
| 	be more efficient as Apache can ask the kernel to copy the | ||||
| 	file contents from the file system directly to the network: | ||||
| + | ||||
| ---------------------------------------------------------------- | ||||
| DocumentRoot /var/www | ||||
|  | ||||
| ScriptAlias /git/        /usr/libexec/git-core/git-http-backend/git/ | ||||
| Alias       /git_static/ /var/www/git/ | ||||
|  | ||||
| RewriteEngine on | ||||
| RewriteRule ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$    /git_static/$1 [PT] | ||||
| RewriteRule ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.pack)$ /git_static/$1 [PT] | ||||
| RewriteRule ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.idx)$  /git_static/$1 [PT] | ||||
| ---------------------------------------------------------------- | ||||
|  | ||||
|  | ||||
| ENVIRONMENT | ||||
| ----------- | ||||
| 'git-http-backend' relies upon the CGI environment variables set | ||||
| by the invoking web server, including: | ||||
|  | ||||
| * PATH_TRANSLATED | ||||
| * REMOTE_USER | ||||
| * REMOTE_ADDR | ||||
| * CONTENT_TYPE | ||||
| * QUERY_STRING | ||||
| * REQUEST_METHOD | ||||
|  | ||||
| Author | ||||
| ------ | ||||
| Written by Shawn O. Pearce <spearce@spearce.org>. | ||||
|  | ||||
| Documentation | ||||
| -------------- | ||||
| Documentation by Shawn O. Pearce <spearce@spearce.org>. | ||||
|  | ||||
| GIT | ||||
| --- | ||||
| Part of the linkgit:git[1] suite | ||||
							
								
								
									
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							|  | @ -365,6 +365,7 @@ PROGRAMS += git-show-index$X | |||
| PROGRAMS += git-unpack-file$X | ||||
| PROGRAMS += git-upload-pack$X | ||||
| PROGRAMS += git-var$X | ||||
| PROGRAMS += git-http-backend$X | ||||
|  | ||||
| # List built-in command $C whose implementation cmd_$C() is not in | ||||
| # builtin-$C.o but is linked in as part of some other command. | ||||
|  |  | |||
|  | @ -0,0 +1,289 @@ | |||
| #include "cache.h" | ||||
| #include "refs.h" | ||||
| #include "pkt-line.h" | ||||
| #include "object.h" | ||||
| #include "tag.h" | ||||
| #include "exec_cmd.h" | ||||
|  | ||||
| static const char content_type[] = "Content-Type"; | ||||
| static const char content_length[] = "Content-Length"; | ||||
| static const char last_modified[] = "Last-Modified"; | ||||
|  | ||||
| static void format_write(int fd, const char *fmt, ...) | ||||
| { | ||||
| 	static char buffer[1024]; | ||||
|  | ||||
| 	va_list args; | ||||
| 	unsigned n; | ||||
|  | ||||
| 	va_start(args, fmt); | ||||
| 	n = vsnprintf(buffer, sizeof(buffer), fmt, args); | ||||
| 	va_end(args); | ||||
| 	if (n >= sizeof(buffer)) | ||||
| 		die("protocol error: impossibly long line"); | ||||
|  | ||||
| 	safe_write(fd, buffer, n); | ||||
| } | ||||
|  | ||||
| static void http_status(unsigned code, const char *msg) | ||||
| { | ||||
| 	format_write(1, "Status: %u %s\r\n", code, msg); | ||||
| } | ||||
|  | ||||
| static void hdr_str(const char *name, const char *value) | ||||
| { | ||||
| 	format_write(1, "%s: %s\r\n", name, value); | ||||
| } | ||||
|  | ||||
| static void hdr_int(const char *name, size_t value) | ||||
| { | ||||
| 	format_write(1, "%s: %" PRIuMAX "\r\n", name, value); | ||||
| } | ||||
|  | ||||
| static void hdr_date(const char *name, unsigned long when) | ||||
| { | ||||
| 	const char *value = show_date(when, 0, DATE_RFC2822); | ||||
| 	hdr_str(name, value); | ||||
| } | ||||
|  | ||||
| static void hdr_nocache(void) | ||||
| { | ||||
| 	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"); | ||||
| } | ||||
|  | ||||
| static void hdr_cache_forever(void) | ||||
| { | ||||
| 	unsigned long now = time(NULL); | ||||
| 	hdr_date("Date", now); | ||||
| 	hdr_date("Expires", now + 31536000); | ||||
| 	hdr_str("Cache-Control", "public, max-age=31536000"); | ||||
| } | ||||
|  | ||||
| static void end_headers(void) | ||||
| { | ||||
| 	safe_write(1, "\r\n", 2); | ||||
| } | ||||
|  | ||||
| static NORETURN void not_found(const char *err, ...) | ||||
| { | ||||
| 	va_list params; | ||||
|  | ||||
| 	http_status(404, "Not Found"); | ||||
| 	hdr_nocache(); | ||||
| 	end_headers(); | ||||
|  | ||||
| 	va_start(params, err); | ||||
| 	if (err && *err) | ||||
| 		vfprintf(stderr, err, params); | ||||
| 	va_end(params); | ||||
| 	exit(0); | ||||
| } | ||||
|  | ||||
| static void send_strbuf(const char *type, struct strbuf *buf) | ||||
| { | ||||
| 	hdr_int(content_length, buf->len); | ||||
| 	hdr_str(content_type, type); | ||||
| 	end_headers(); | ||||
| 	safe_write(1, buf->buf, buf->len); | ||||
| } | ||||
|  | ||||
| static void send_file(const char *the_type, const char *name) | ||||
| { | ||||
| 	const char *p = git_path("%s", name); | ||||
| 	size_t buf_alloc = 8192; | ||||
| 	char *buf = xmalloc(buf_alloc); | ||||
| 	int fd; | ||||
| 	struct stat sb; | ||||
| 	size_t size; | ||||
|  | ||||
| 	fd = open(p, O_RDONLY); | ||||
| 	if (fd < 0) | ||||
| 		not_found("Cannot open '%s': %s", p, strerror(errno)); | ||||
| 	if (fstat(fd, &sb) < 0) | ||||
| 		die_errno("Cannot stat '%s'", p); | ||||
|  | ||||
| 	size = xsize_t(sb.st_size); | ||||
|  | ||||
| 	hdr_int(content_length, size); | ||||
| 	hdr_str(content_type, the_type); | ||||
| 	hdr_date(last_modified, sb.st_mtime); | ||||
| 	end_headers(); | ||||
|  | ||||
| 	while (size) { | ||||
| 		ssize_t n = xread(fd, buf, buf_alloc); | ||||
| 		if (n < 0) | ||||
| 			die_errno("Cannot read '%s'", p); | ||||
| 		if (!n) | ||||
| 			break; | ||||
| 		safe_write(1, buf, n); | ||||
| 	} | ||||
| 	close(fd); | ||||
| 	free(buf); | ||||
| } | ||||
|  | ||||
| static void get_text_file(char *name) | ||||
| { | ||||
| 	hdr_nocache(); | ||||
| 	send_file("text/plain", name); | ||||
| } | ||||
|  | ||||
| static void get_loose_object(char *name) | ||||
| { | ||||
| 	hdr_cache_forever(); | ||||
| 	send_file("application/x-git-loose-object", name); | ||||
| } | ||||
|  | ||||
| static void get_pack_file(char *name) | ||||
| { | ||||
| 	hdr_cache_forever(); | ||||
| 	send_file("application/x-git-packed-objects", name); | ||||
| } | ||||
|  | ||||
| static void get_idx_file(char *name) | ||||
| { | ||||
| 	hdr_cache_forever(); | ||||
| 	send_file("application/x-git-packed-objects-toc", name); | ||||
| } | ||||
|  | ||||
| static int show_text_ref(const char *name, const unsigned char *sha1, | ||||
| 	int flag, void *cb_data) | ||||
| { | ||||
| 	struct strbuf *buf = cb_data; | ||||
| 	struct object *o = parse_object(sha1); | ||||
| 	if (!o) | ||||
| 		return 0; | ||||
|  | ||||
| 	strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name); | ||||
| 	if (o->type == OBJ_TAG) { | ||||
| 		o = deref_tag(o, name, 0); | ||||
| 		if (!o) | ||||
| 			return 0; | ||||
| 		strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name); | ||||
| 	} | ||||
| 	return 0; | ||||
| } | ||||
|  | ||||
| static void get_info_refs(char *arg) | ||||
| { | ||||
| 	struct strbuf buf = STRBUF_INIT; | ||||
|  | ||||
| 	for_each_ref(show_text_ref, &buf); | ||||
| 	hdr_nocache(); | ||||
| 	send_strbuf("text/plain", &buf); | ||||
| 	strbuf_release(&buf); | ||||
| } | ||||
|  | ||||
| static void get_info_packs(char *arg) | ||||
| { | ||||
| 	size_t objdirlen = strlen(get_object_directory()); | ||||
| 	struct strbuf buf = STRBUF_INIT; | ||||
| 	struct packed_git *p; | ||||
| 	size_t cnt = 0; | ||||
|  | ||||
| 	prepare_packed_git(); | ||||
| 	for (p = packed_git; p; p = p->next) { | ||||
| 		if (p->pack_local) | ||||
| 			cnt++; | ||||
| 	} | ||||
|  | ||||
| 	strbuf_grow(&buf, cnt * 53 + 2); | ||||
| 	for (p = packed_git; p; p = p->next) { | ||||
| 		if (p->pack_local) | ||||
| 			strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6); | ||||
| 	} | ||||
| 	strbuf_addch(&buf, '\n'); | ||||
|  | ||||
| 	hdr_nocache(); | ||||
| 	send_strbuf("text/plain; charset=utf-8", &buf); | ||||
| 	strbuf_release(&buf); | ||||
| } | ||||
|  | ||||
| static NORETURN void die_webcgi(const char *err, va_list params) | ||||
| { | ||||
| 	char buffer[1000]; | ||||
|  | ||||
| 	http_status(500, "Internal Server Error"); | ||||
| 	hdr_nocache(); | ||||
| 	end_headers(); | ||||
|  | ||||
| 	vsnprintf(buffer, sizeof(buffer), err, params); | ||||
| 	fprintf(stderr, "fatal: %s\n", buffer); | ||||
| 	exit(0); | ||||
| } | ||||
|  | ||||
| static struct service_cmd { | ||||
| 	const char *method; | ||||
| 	const char *pattern; | ||||
| 	void (*imp)(char *); | ||||
| } services[] = { | ||||
| 	{"GET", "/HEAD$", get_text_file}, | ||||
| 	{"GET", "/info/refs$", get_info_refs}, | ||||
| 	{"GET", "/objects/info/alternates$", get_text_file}, | ||||
| 	{"GET", "/objects/info/http-alternates$", get_text_file}, | ||||
| 	{"GET", "/objects/info/packs$", get_info_packs}, | ||||
| 	{"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object}, | ||||
| 	{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file}, | ||||
| 	{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file} | ||||
| }; | ||||
|  | ||||
| int main(int argc, char **argv) | ||||
| { | ||||
| 	char *method = getenv("REQUEST_METHOD"); | ||||
| 	char *dir = getenv("PATH_TRANSLATED"); | ||||
| 	struct service_cmd *cmd = NULL; | ||||
| 	char *cmd_arg = NULL; | ||||
| 	int i; | ||||
|  | ||||
| 	git_extract_argv0_path(argv[0]); | ||||
| 	set_die_routine(die_webcgi); | ||||
|  | ||||
| 	if (!method) | ||||
| 		die("No REQUEST_METHOD from server"); | ||||
| 	if (!strcmp(method, "HEAD")) | ||||
| 		method = "GET"; | ||||
| 	if (!dir) | ||||
| 		die("No PATH_TRANSLATED from server"); | ||||
|  | ||||
| 	for (i = 0; i < ARRAY_SIZE(services); i++) { | ||||
| 		struct service_cmd *c = &services[i]; | ||||
| 		regex_t re; | ||||
| 		regmatch_t out[1]; | ||||
|  | ||||
| 		if (regcomp(&re, c->pattern, REG_EXTENDED)) | ||||
| 			die("Bogus regex in service table: %s", c->pattern); | ||||
| 		if (!regexec(&re, dir, 1, out, 0)) { | ||||
| 			size_t n = out[0].rm_eo - out[0].rm_so; | ||||
|  | ||||
| 			if (strcmp(method, c->method)) { | ||||
| 				const char *proto = getenv("SERVER_PROTOCOL"); | ||||
| 				if (proto && !strcmp(proto, "HTTP/1.1")) | ||||
| 					http_status(405, "Method Not Allowed"); | ||||
| 				else | ||||
| 					http_status(400, "Bad Request"); | ||||
| 				hdr_nocache(); | ||||
| 				end_headers(); | ||||
| 				return 0; | ||||
| 			} | ||||
|  | ||||
| 			cmd = c; | ||||
| 			cmd_arg = xmalloc(n); | ||||
| 			strncpy(cmd_arg, dir + out[0].rm_so + 1, n); | ||||
| 			cmd_arg[n] = '\0'; | ||||
| 			dir[out[0].rm_so] = 0; | ||||
| 			break; | ||||
| 		} | ||||
| 		regfree(&re); | ||||
| 	} | ||||
|  | ||||
| 	if (!cmd) | ||||
| 		not_found("Request not supported: '%s'", dir); | ||||
|  | ||||
| 	setup_path(); | ||||
| 	if (!enter_repo(dir, 0)) | ||||
| 		not_found("Not a git repository: '%s'", dir); | ||||
|  | ||||
| 	cmd->imp(cmd_arg); | ||||
| 	return 0; | ||||
| } | ||||
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	 Shawn O. Pearce
						Shawn O. Pearce