diff options
| -rw-r--r-- | .gitignore | 1 | ||||
| -rw-r--r-- | Documentation/git-http-backend.txt | 105 | ||||
| -rw-r--r-- | Makefile | 1 | ||||
| -rw-r--r-- | http-backend.c | 289 |
4 files changed, 396 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore index 51a37b1af..353d22fc9 100644 --- a/.gitignore +++ b/.gitignore @@ -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 diff --git a/Documentation/git-http-backend.txt b/Documentation/git-http-backend.txt new file mode 100644 index 000000000..867675fce --- /dev/null +++ b/Documentation/git-http-backend.txt @@ -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/$1 [PT] +---------------------------------------------------------------- + + +ENVIRONMENT +----------- +'git-http-backend' relies upon the CGI environment variables set +by the invoking web server, including: + +* PATH_TRANSLATED +* REMOTE_USER +* REMOTE_ADDR +* CONTENT_TYPE +* QUERY_STRING +* REQUEST_METHOD + +Author +------ +Written by Shawn O. Pearce <spearce@spearce.org>. + +Documentation +-------------- +Documentation by Shawn O. Pearce <spearce@spearce.org>. + +GIT +--- +Part of the linkgit:git[1] suite @@ -365,6 +365,7 @@ PROGRAMS += git-show-index$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. diff --git a/http-backend.c b/http-backend.c new file mode 100644 index 000000000..22bec56b9 --- /dev/null +++ b/http-backend.c @@ -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; +} |