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![Jeff King](/assets/img/avatar_default.png)
When we die() in http-backend, we call a custom handler that
writes an HTTP 500 response to stdout, then reports the
error to stderr. Our routines for writing out the HTTP
response may themselves die, leading to us entering die()
again.
When it was originally written, that was OK; our custom
handler keeps a variable to notice this and does not
recurse. However, since cd163d4
(usage.c: detect recursion
in die routines and bail out immediately, 2012-11-14), the
main die() implementation detects recursion before we even
get to our custom handler, and bails without printing
anything useful.
We can handle this case by doing two things:
1. Installing a custom die_is_recursing handler that
allows us to enter up to one level of recursion. Only
the first call to our custom handler will try to write
out the error response. So if we die again, that is OK.
If we end up dying more than that, it is a sign that we
are in an infinite recursion.
2. Reporting the error to stderr before trying to write
out the HTTP response. In the current code, if we do
die() trying to write out the response, we'll exit
immediately from this second die(), and never get a
chance to output the original error (which is almost
certainly the more interesting one; the second die is
just going to be along the lines of "I tried to write
to stdout but it was closed").
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
629 lines
14 KiB
C
629 lines
14 KiB
C
#include "cache.h"
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#include "refs.h"
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#include "pkt-line.h"
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#include "object.h"
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#include "tag.h"
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#include "exec_cmd.h"
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#include "run-command.h"
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#include "string-list.h"
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#include "url.h"
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#include "argv-array.h"
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static const char content_type[] = "Content-Type";
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static const char content_length[] = "Content-Length";
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static const char last_modified[] = "Last-Modified";
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static int getanyfile = 1;
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static struct string_list *query_params;
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struct rpc_service {
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const char *name;
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const char *config_name;
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signed enabled : 2;
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};
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static struct rpc_service rpc_service[] = {
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{ "upload-pack", "uploadpack", 1 },
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{ "receive-pack", "receivepack", -1 },
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};
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static struct string_list *get_parameters(void)
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{
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if (!query_params) {
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const char *query = getenv("QUERY_STRING");
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query_params = xcalloc(1, sizeof(*query_params));
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while (query && *query) {
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char *name = url_decode_parameter_name(&query);
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char *value = url_decode_parameter_value(&query);
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struct string_list_item *i;
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i = string_list_lookup(query_params, name);
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if (!i)
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i = string_list_insert(query_params, name);
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else
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free(i->util);
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i->util = value;
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}
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}
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return query_params;
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}
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static const char *get_parameter(const char *name)
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{
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struct string_list_item *i;
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i = string_list_lookup(get_parameters(), name);
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return i ? i->util : NULL;
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}
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__attribute__((format (printf, 2, 3)))
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static void format_write(int fd, const char *fmt, ...)
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{
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static char buffer[1024];
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va_list args;
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unsigned n;
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va_start(args, fmt);
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n = vsnprintf(buffer, sizeof(buffer), fmt, args);
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va_end(args);
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if (n >= sizeof(buffer))
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die("protocol error: impossibly long line");
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write_or_die(fd, buffer, n);
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}
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static void http_status(unsigned code, const char *msg)
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{
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format_write(1, "Status: %u %s\r\n", code, msg);
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}
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static void hdr_str(const char *name, const char *value)
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{
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format_write(1, "%s: %s\r\n", name, value);
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}
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static void hdr_int(const char *name, uintmax_t value)
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{
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format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
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}
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static void hdr_date(const char *name, unsigned long when)
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{
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const char *value = show_date(when, 0, DATE_RFC2822);
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hdr_str(name, value);
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}
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static void hdr_nocache(void)
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{
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hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
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hdr_str("Pragma", "no-cache");
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hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
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}
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static void hdr_cache_forever(void)
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{
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unsigned long now = time(NULL);
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hdr_date("Date", now);
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hdr_date("Expires", now + 31536000);
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hdr_str("Cache-Control", "public, max-age=31536000");
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}
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static void end_headers(void)
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{
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write_or_die(1, "\r\n", 2);
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}
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__attribute__((format (printf, 1, 2)))
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static NORETURN void not_found(const char *err, ...)
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{
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va_list params;
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http_status(404, "Not Found");
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hdr_nocache();
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end_headers();
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va_start(params, err);
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if (err && *err)
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vfprintf(stderr, err, params);
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va_end(params);
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exit(0);
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}
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__attribute__((format (printf, 1, 2)))
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static NORETURN void forbidden(const char *err, ...)
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{
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va_list params;
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http_status(403, "Forbidden");
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hdr_nocache();
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end_headers();
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va_start(params, err);
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if (err && *err)
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vfprintf(stderr, err, params);
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va_end(params);
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exit(0);
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}
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static void select_getanyfile(void)
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{
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if (!getanyfile)
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forbidden("Unsupported service: getanyfile");
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}
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static void send_strbuf(const char *type, struct strbuf *buf)
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{
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hdr_int(content_length, buf->len);
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hdr_str(content_type, type);
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end_headers();
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write_or_die(1, buf->buf, buf->len);
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}
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static void send_local_file(const char *the_type, const char *name)
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{
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const char *p = git_path("%s", name);
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size_t buf_alloc = 8192;
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char *buf = xmalloc(buf_alloc);
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int fd;
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struct stat sb;
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fd = open(p, O_RDONLY);
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if (fd < 0)
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not_found("Cannot open '%s': %s", p, strerror(errno));
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if (fstat(fd, &sb) < 0)
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die_errno("Cannot stat '%s'", p);
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hdr_int(content_length, sb.st_size);
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hdr_str(content_type, the_type);
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hdr_date(last_modified, sb.st_mtime);
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end_headers();
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for (;;) {
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ssize_t n = xread(fd, buf, buf_alloc);
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if (n < 0)
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die_errno("Cannot read '%s'", p);
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if (!n)
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break;
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write_or_die(1, buf, n);
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}
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close(fd);
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free(buf);
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}
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static void get_text_file(char *name)
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{
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select_getanyfile();
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hdr_nocache();
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send_local_file("text/plain", name);
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}
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static void get_loose_object(char *name)
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{
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select_getanyfile();
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hdr_cache_forever();
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send_local_file("application/x-git-loose-object", name);
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}
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static void get_pack_file(char *name)
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{
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select_getanyfile();
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hdr_cache_forever();
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send_local_file("application/x-git-packed-objects", name);
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}
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static void get_idx_file(char *name)
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{
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select_getanyfile();
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hdr_cache_forever();
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send_local_file("application/x-git-packed-objects-toc", name);
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}
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static void http_config(void)
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{
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int i, value = 0;
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struct strbuf var = STRBUF_INIT;
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git_config_get_bool("http.getanyfile", &getanyfile);
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for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
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struct rpc_service *svc = &rpc_service[i];
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strbuf_addf(&var, "http.%s", svc->config_name);
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if (!git_config_get_bool(var.buf, &value))
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svc->enabled = value;
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strbuf_reset(&var);
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}
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strbuf_release(&var);
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}
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static struct rpc_service *select_service(const char *name)
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{
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const char *svc_name;
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struct rpc_service *svc = NULL;
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int i;
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if (!skip_prefix(name, "git-", &svc_name))
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forbidden("Unsupported service: '%s'", name);
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for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
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struct rpc_service *s = &rpc_service[i];
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if (!strcmp(s->name, svc_name)) {
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svc = s;
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break;
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}
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}
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if (!svc)
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forbidden("Unsupported service: '%s'", name);
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if (svc->enabled < 0) {
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const char *user = getenv("REMOTE_USER");
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svc->enabled = (user && *user) ? 1 : 0;
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}
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if (!svc->enabled)
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forbidden("Service not enabled: '%s'", svc->name);
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return svc;
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}
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static void inflate_request(const char *prog_name, int out)
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{
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git_zstream stream;
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unsigned char in_buf[8192];
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unsigned char out_buf[8192];
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unsigned long cnt = 0;
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memset(&stream, 0, sizeof(stream));
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git_inflate_init_gzip_only(&stream);
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while (1) {
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ssize_t n = xread(0, in_buf, sizeof(in_buf));
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if (n <= 0)
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die("request ended in the middle of the gzip stream");
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stream.next_in = in_buf;
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stream.avail_in = n;
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while (0 < stream.avail_in) {
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int ret;
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stream.next_out = out_buf;
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stream.avail_out = sizeof(out_buf);
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ret = git_inflate(&stream, Z_NO_FLUSH);
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if (ret != Z_OK && ret != Z_STREAM_END)
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die("zlib error inflating request, result %d", ret);
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n = stream.total_out - cnt;
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if (write_in_full(out, out_buf, n) != n)
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die("%s aborted reading request", prog_name);
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cnt += n;
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if (ret == Z_STREAM_END)
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goto done;
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}
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}
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done:
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git_inflate_end(&stream);
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close(out);
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}
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static void run_service(const char **argv)
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{
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const char *encoding = getenv("HTTP_CONTENT_ENCODING");
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const char *user = getenv("REMOTE_USER");
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const char *host = getenv("REMOTE_ADDR");
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int gzipped_request = 0;
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struct child_process cld = CHILD_PROCESS_INIT;
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if (encoding && !strcmp(encoding, "gzip"))
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gzipped_request = 1;
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else if (encoding && !strcmp(encoding, "x-gzip"))
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gzipped_request = 1;
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if (!user || !*user)
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user = "anonymous";
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if (!host || !*host)
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host = "(none)";
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if (!getenv("GIT_COMMITTER_NAME"))
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argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
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if (!getenv("GIT_COMMITTER_EMAIL"))
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argv_array_pushf(&cld.env_array,
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"GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
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cld.argv = argv;
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if (gzipped_request)
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cld.in = -1;
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cld.git_cmd = 1;
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if (start_command(&cld))
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exit(1);
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close(1);
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if (gzipped_request)
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inflate_request(argv[0], cld.in);
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else
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close(0);
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if (finish_command(&cld))
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exit(1);
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}
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static int show_text_ref(const char *name, const unsigned char *sha1,
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int flag, void *cb_data)
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{
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const char *name_nons = strip_namespace(name);
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struct strbuf *buf = cb_data;
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struct object *o = parse_object(sha1);
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if (!o)
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return 0;
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strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name_nons);
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if (o->type == OBJ_TAG) {
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o = deref_tag(o, name, 0);
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if (!o)
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return 0;
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strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1),
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name_nons);
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}
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return 0;
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}
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static void get_info_refs(char *arg)
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{
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const char *service_name = get_parameter("service");
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struct strbuf buf = STRBUF_INIT;
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hdr_nocache();
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if (service_name) {
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const char *argv[] = {NULL /* service name */,
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"--stateless-rpc", "--advertise-refs",
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".", NULL};
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struct rpc_service *svc = select_service(service_name);
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strbuf_addf(&buf, "application/x-git-%s-advertisement",
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svc->name);
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hdr_str(content_type, buf.buf);
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end_headers();
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packet_write(1, "# service=git-%s\n", svc->name);
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packet_flush(1);
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argv[0] = svc->name;
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run_service(argv);
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} else {
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select_getanyfile();
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for_each_namespaced_ref(show_text_ref, &buf);
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send_strbuf("text/plain", &buf);
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}
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strbuf_release(&buf);
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}
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static int show_head_ref(const char *refname, const unsigned char *sha1,
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int flag, void *cb_data)
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{
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struct strbuf *buf = cb_data;
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if (flag & REF_ISSYMREF) {
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unsigned char unused[20];
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const char *target = resolve_ref_unsafe(refname,
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RESOLVE_REF_READING,
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unused, NULL);
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const char *target_nons = strip_namespace(target);
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strbuf_addf(buf, "ref: %s\n", target_nons);
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} else {
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strbuf_addf(buf, "%s\n", sha1_to_hex(sha1));
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}
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return 0;
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}
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static void get_head(char *arg)
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{
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struct strbuf buf = STRBUF_INIT;
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select_getanyfile();
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head_ref_namespaced(show_head_ref, &buf);
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send_strbuf("text/plain", &buf);
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strbuf_release(&buf);
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}
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static void get_info_packs(char *arg)
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{
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size_t objdirlen = strlen(get_object_directory());
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struct strbuf buf = STRBUF_INIT;
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struct packed_git *p;
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size_t cnt = 0;
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select_getanyfile();
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prepare_packed_git();
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for (p = packed_git; p; p = p->next) {
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if (p->pack_local)
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cnt++;
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}
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strbuf_grow(&buf, cnt * 53 + 2);
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for (p = packed_git; p; p = p->next) {
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if (p->pack_local)
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strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
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}
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strbuf_addch(&buf, '\n');
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|
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hdr_nocache();
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send_strbuf("text/plain; charset=utf-8", &buf);
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strbuf_release(&buf);
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}
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|
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static void check_content_type(const char *accepted_type)
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{
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const char *actual_type = getenv("CONTENT_TYPE");
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|
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if (!actual_type)
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actual_type = "";
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|
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if (strcmp(actual_type, accepted_type)) {
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http_status(415, "Unsupported Media Type");
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hdr_nocache();
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end_headers();
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format_write(1,
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"Expected POST with Content-Type '%s',"
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" but received '%s' instead.\n",
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accepted_type, actual_type);
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exit(0);
|
|
}
|
|
}
|
|
|
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static void service_rpc(char *service_name)
|
|
{
|
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const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
|
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struct rpc_service *svc = select_service(service_name);
|
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struct strbuf buf = STRBUF_INIT;
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|
|
strbuf_reset(&buf);
|
|
strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
|
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check_content_type(buf.buf);
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|
|
|
hdr_nocache();
|
|
|
|
strbuf_reset(&buf);
|
|
strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
|
|
hdr_str(content_type, buf.buf);
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|
|
end_headers();
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|
|
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argv[0] = svc->name;
|
|
run_service(argv);
|
|
strbuf_release(&buf);
|
|
}
|
|
|
|
static int dead;
|
|
static NORETURN void die_webcgi(const char *err, va_list params)
|
|
{
|
|
if (dead <= 1) {
|
|
vreportf("fatal: ", err, params);
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|
|
http_status(500, "Internal Server Error");
|
|
hdr_nocache();
|
|
end_headers();
|
|
}
|
|
exit(0); /* we successfully reported a failure ;-) */
|
|
}
|
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|
|
static int die_webcgi_recursing(void)
|
|
{
|
|
return dead++ > 1;
|
|
}
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|
|
|
static char* getdir(void)
|
|
{
|
|
struct strbuf buf = STRBUF_INIT;
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char *pathinfo = getenv("PATH_INFO");
|
|
char *root = getenv("GIT_PROJECT_ROOT");
|
|
char *path = getenv("PATH_TRANSLATED");
|
|
|
|
if (root && *root) {
|
|
if (!pathinfo || !*pathinfo)
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|
die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
|
|
if (daemon_avoid_alias(pathinfo))
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|
die("'%s': aliased", pathinfo);
|
|
end_url_with_slash(&buf, root);
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|
if (pathinfo[0] == '/')
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|
pathinfo++;
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|
strbuf_addstr(&buf, pathinfo);
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|
return strbuf_detach(&buf, NULL);
|
|
} else if (path && *path) {
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|
return xstrdup(path);
|
|
} else
|
|
die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
|
|
return NULL;
|
|
}
|
|
|
|
static struct service_cmd {
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|
const char *method;
|
|
const char *pattern;
|
|
void (*imp)(char *);
|
|
} services[] = {
|
|
{"GET", "/HEAD$", get_head},
|
|
{"GET", "/info/refs$", 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},
|
|
|
|
{"POST", "/git-upload-pack$", service_rpc},
|
|
{"POST", "/git-receive-pack$", service_rpc}
|
|
};
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
char *method = getenv("REQUEST_METHOD");
|
|
char *dir;
|
|
struct service_cmd *cmd = NULL;
|
|
char *cmd_arg = NULL;
|
|
int i;
|
|
|
|
git_setup_gettext();
|
|
|
|
git_extract_argv0_path(argv[0]);
|
|
set_die_routine(die_webcgi);
|
|
set_die_is_recursing_routine(die_webcgi_recursing);
|
|
|
|
if (!method)
|
|
die("No REQUEST_METHOD from server");
|
|
if (!strcmp(method, "HEAD"))
|
|
method = "GET";
|
|
dir = getdir();
|
|
|
|
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;
|
|
|
|
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;
|
|
}
|
|
|
|
cmd = c;
|
|
n = out[0].rm_eo - out[0].rm_so;
|
|
cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
|
|
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);
|
|
if (!getenv("GIT_HTTP_EXPORT_ALL") &&
|
|
access("git-daemon-export-ok", F_OK) )
|
|
not_found("Repository not exported: '%s'", dir);
|
|
|
|
http_config();
|
|
cmd->imp(cmd_arg);
|
|
return 0;
|
|
}
|