git/ls-refs.c
Junio C Hamano bb1677fc29 Merge branch 'jk/reduce-malloc-in-v2-servers'
Code cleanup to limit memory consumption and tighten protocol
message parsing.

* jk/reduce-malloc-in-v2-servers:
  ls-refs: reject unknown arguments
  serve: reject commands used as capabilities
  serve: reject bogus v2 "command=ls-refs=foo"
  docs/protocol-v2: clarify some ls-refs ref-prefix details
  ls-refs: ignore very long ref-prefix counts
  serve: drop "keys" strvec
  serve: provide "receive" function for session-id capability
  serve: provide "receive" function for object-format capability
  serve: add "receive" method for v2 capabilities table
  serve: return capability "value" from get_capability()
  serve: rename is_command() to parse_command()
2021-09-28 13:06:53 -07:00

209 lines
4.9 KiB
C

#include "cache.h"
#include "repository.h"
#include "refs.h"
#include "remote.h"
#include "strvec.h"
#include "ls-refs.h"
#include "pkt-line.h"
#include "config.h"
static int config_read;
static int advertise_unborn;
static int allow_unborn;
static void ensure_config_read(void)
{
const char *str = NULL;
if (config_read)
return;
if (repo_config_get_string_tmp(the_repository, "lsrefs.unborn", &str)) {
/*
* If there is no such config, advertise and allow it by
* default.
*/
advertise_unborn = 1;
allow_unborn = 1;
} else {
if (!strcmp(str, "advertise")) {
advertise_unborn = 1;
allow_unborn = 1;
} else if (!strcmp(str, "allow")) {
allow_unborn = 1;
} else if (!strcmp(str, "ignore")) {
/* do nothing */
} else {
die(_("invalid value '%s' for lsrefs.unborn"), str);
}
}
config_read = 1;
}
/*
* If we see this many or more "ref-prefix" lines from the client, we consider
* it "too many" and will avoid using the prefix feature entirely.
*/
#define TOO_MANY_PREFIXES 65536
/*
* Check if one of the prefixes is a prefix of the ref.
* If no prefixes were provided, all refs match.
*/
static int ref_match(const struct strvec *prefixes, const char *refname)
{
int i;
if (!prefixes->nr)
return 1; /* no restriction */
for (i = 0; i < prefixes->nr; i++) {
const char *prefix = prefixes->v[i];
if (starts_with(refname, prefix))
return 1;
}
return 0;
}
struct ls_refs_data {
unsigned peel;
unsigned symrefs;
struct strvec prefixes;
struct strbuf buf;
unsigned unborn : 1;
};
static int send_ref(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
struct ls_refs_data *data = cb_data;
const char *refname_nons = strip_namespace(refname);
strbuf_reset(&data->buf);
if (ref_is_hidden(refname_nons, refname))
return 0;
if (!ref_match(&data->prefixes, refname_nons))
return 0;
if (oid)
strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
else
strbuf_addf(&data->buf, "unborn %s", refname_nons);
if (data->symrefs && flag & REF_ISSYMREF) {
struct object_id unused;
const char *symref_target = resolve_ref_unsafe(refname, 0,
&unused,
&flag);
if (!symref_target)
die("'%s' is a symref but it is not?", refname);
strbuf_addf(&data->buf, " symref-target:%s",
strip_namespace(symref_target));
}
if (data->peel && oid) {
struct object_id peeled;
if (!peel_iterated_oid(oid, &peeled))
strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
}
strbuf_addch(&data->buf, '\n');
packet_fwrite(stdout, data->buf.buf, data->buf.len);
return 0;
}
static void send_possibly_unborn_head(struct ls_refs_data *data)
{
struct strbuf namespaced = STRBUF_INIT;
struct object_id oid;
int flag;
int oid_is_null;
strbuf_addf(&namespaced, "%sHEAD", get_git_namespace());
if (!resolve_ref_unsafe(namespaced.buf, 0, &oid, &flag))
return; /* bad ref */
oid_is_null = is_null_oid(&oid);
if (!oid_is_null ||
(data->unborn && data->symrefs && (flag & REF_ISSYMREF)))
send_ref(namespaced.buf, oid_is_null ? NULL : &oid, flag, data);
strbuf_release(&namespaced);
}
static int ls_refs_config(const char *var, const char *value, void *data)
{
/*
* We only serve fetches over v2 for now, so respect only "uploadpack"
* config. This may need to eventually be expanded to "receive", but we
* don't yet know how that information will be passed to ls-refs.
*/
return parse_hide_refs_config(var, value, "uploadpack");
}
int ls_refs(struct repository *r, struct packet_reader *request)
{
struct ls_refs_data data;
memset(&data, 0, sizeof(data));
strvec_init(&data.prefixes);
strbuf_init(&data.buf, 0);
ensure_config_read();
git_config(ls_refs_config, NULL);
while (packet_reader_read(request) == PACKET_READ_NORMAL) {
const char *arg = request->line;
const char *out;
if (!strcmp("peel", arg))
data.peel = 1;
else if (!strcmp("symrefs", arg))
data.symrefs = 1;
else if (skip_prefix(arg, "ref-prefix ", &out)) {
if (data.prefixes.nr < TOO_MANY_PREFIXES)
strvec_push(&data.prefixes, out);
}
else if (!strcmp("unborn", arg))
data.unborn = allow_unborn;
else
die(_("unexpected line: '%s'"), arg);
}
if (request->status != PACKET_READ_FLUSH)
die(_("expected flush after ls-refs arguments"));
/*
* If we saw too many prefixes, we must avoid using them at all; as
* soon as we have any prefix, they are meant to form a comprehensive
* list.
*/
if (data.prefixes.nr >= TOO_MANY_PREFIXES)
strvec_clear(&data.prefixes);
send_possibly_unborn_head(&data);
if (!data.prefixes.nr)
strvec_push(&data.prefixes, "");
for_each_fullref_in_prefixes(get_git_namespace(), data.prefixes.v,
send_ref, &data, 0);
packet_fflush(stdout);
strvec_clear(&data.prefixes);
strbuf_release(&data.buf);
return 0;
}
int ls_refs_advertise(struct repository *r, struct strbuf *value)
{
if (value) {
ensure_config_read();
if (advertise_unborn)
strbuf_addstr(value, "unborn");
}
return 1;
}