git/http-backend.c
Ævar Arnfjörð Bjarmason 6def0ff878 run-command API users: use strvec_pushv(), not argv assignment
Migrate those run-command API users that assign directly to the "argv"
member to use a strvec_pushv() of "args" instead.

In these cases it did not make sense to further refactor these
callers, e.g. daemon.c could be made to construct the arguments closer
to handle(), but that would require moving the construction from its
cmd_main() and pass "argv" through two intermediate functions.

It would be possible for a change like this to introduce a regression
if we were doing:

      cp.argv = argv;
      argv[1] = "foo";

And changed the code, as is being done here, to:

      strvec_pushv(&cp.args, argv);
      argv[1] = "foo";

But as viewing this change with the "-W" flag reveals none of these
functions modify variable that's being pushed afterwards in a way that
would introduce such a logic error.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-25 22:15:07 -08:00

798 lines
19 KiB
C

#include "cache.h"
#include "config.h"
#include "repository.h"
#include "refs.h"
#include "pkt-line.h"
#include "object.h"
#include "tag.h"
#include "exec-cmd.h"
#include "run-command.h"
#include "string-list.h"
#include "url.h"
#include "strvec.h"
#include "packfile.h"
#include "object-store.h"
#include "protocol.h"
static const char content_type[] = "Content-Type";
static const char content_length[] = "Content-Length";
static const char last_modified[] = "Last-Modified";
static int getanyfile = 1;
static unsigned long max_request_buffer = 10 * 1024 * 1024;
static struct string_list *query_params;
struct rpc_service {
const char *name;
const char *config_name;
unsigned buffer_input : 1;
signed enabled : 2;
};
static struct rpc_service rpc_service[] = {
{ "upload-pack", "uploadpack", 1, 1 },
{ "receive-pack", "receivepack", 0, -1 },
};
static struct string_list *get_parameters(void)
{
if (!query_params) {
const char *query = getenv("QUERY_STRING");
CALLOC_ARRAY(query_params, 1);
while (query && *query) {
char *name = url_decode_parameter_name(&query);
char *value = url_decode_parameter_value(&query);
struct string_list_item *i;
i = string_list_lookup(query_params, name);
if (!i)
i = string_list_insert(query_params, name);
else
free(i->util);
i->util = value;
}
}
return query_params;
}
static const char *get_parameter(const char *name)
{
struct string_list_item *i;
i = string_list_lookup(get_parameters(), name);
return i ? i->util : NULL;
}
__attribute__((format (printf, 2, 3)))
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");
write_or_die(fd, buffer, n);
}
static void http_status(struct strbuf *hdr, unsigned code, const char *msg)
{
strbuf_addf(hdr, "Status: %u %s\r\n", code, msg);
}
static void hdr_str(struct strbuf *hdr, const char *name, const char *value)
{
strbuf_addf(hdr, "%s: %s\r\n", name, value);
}
static void hdr_int(struct strbuf *hdr, const char *name, uintmax_t value)
{
strbuf_addf(hdr, "%s: %" PRIuMAX "\r\n", name, value);
}
static void hdr_date(struct strbuf *hdr, const char *name, timestamp_t when)
{
const char *value = show_date(when, 0, DATE_MODE(RFC2822));
hdr_str(hdr, name, value);
}
static void hdr_nocache(struct strbuf *hdr)
{
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(struct strbuf *hdr)
{
timestamp_t now = time(NULL);
hdr_date(hdr, "Date", now);
hdr_date(hdr, "Expires", now + 31536000);
hdr_str(hdr, "Cache-Control", "public, max-age=31536000");
}
static void end_headers(struct strbuf *hdr)
{
strbuf_add(hdr, "\r\n", 2);
write_or_die(1, hdr->buf, hdr->len);
strbuf_release(hdr);
}
__attribute__((format (printf, 2, 3)))
static NORETURN void not_found(struct strbuf *hdr, const char *err, ...)
{
va_list params;
http_status(hdr, 404, "Not Found");
hdr_nocache(hdr);
end_headers(hdr);
va_start(params, err);
if (err && *err)
vfprintf(stderr, err, params);
va_end(params);
exit(0);
}
__attribute__((format (printf, 2, 3)))
static NORETURN void forbidden(struct strbuf *hdr, const char *err, ...)
{
va_list params;
http_status(hdr, 403, "Forbidden");
hdr_nocache(hdr);
end_headers(hdr);
va_start(params, err);
if (err && *err)
vfprintf(stderr, err, params);
va_end(params);
exit(0);
}
static void select_getanyfile(struct strbuf *hdr)
{
if (!getanyfile)
forbidden(hdr, "Unsupported service: getanyfile");
}
static void send_strbuf(struct strbuf *hdr,
const char *type, struct strbuf *buf)
{
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(struct strbuf *hdr, const char *the_type,
const char *name)
{
char *p = git_pathdup("%s", name);
size_t buf_alloc = 8192;
char *buf = xmalloc(buf_alloc);
int fd;
struct stat sb;
fd = open(p, O_RDONLY);
if (fd < 0)
not_found(hdr, "Cannot open '%s': %s", p, strerror(errno));
if (fstat(fd, &sb) < 0)
die_errno("Cannot stat '%s'", p);
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);
if (n < 0)
die_errno("Cannot read '%s'", p);
if (!n)
break;
write_or_die(1, buf, n);
}
close(fd);
free(buf);
free(p);
}
static void get_text_file(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_nocache(hdr);
send_local_file(hdr, "text/plain", name);
}
static void get_loose_object(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_cache_forever(hdr);
send_local_file(hdr, "application/x-git-loose-object", name);
}
static void get_pack_file(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_cache_forever(hdr);
send_local_file(hdr, "application/x-git-packed-objects", name);
}
static void get_idx_file(struct strbuf *hdr, char *name)
{
select_getanyfile(hdr);
hdr_cache_forever(hdr);
send_local_file(hdr, "application/x-git-packed-objects-toc", name);
}
static void http_config(void)
{
int i, value = 0;
struct strbuf var = STRBUF_INIT;
git_config_get_bool("http.getanyfile", &getanyfile);
git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
struct rpc_service *svc = &rpc_service[i];
strbuf_addf(&var, "http.%s", svc->config_name);
if (!git_config_get_bool(var.buf, &value))
svc->enabled = value;
strbuf_reset(&var);
}
strbuf_release(&var);
}
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(hdr, "Unsupported service: '%s'", name);
for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
struct rpc_service *s = &rpc_service[i];
if (!strcmp(s->name, svc_name)) {
svc = s;
break;
}
}
if (!svc)
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(hdr, "Service not enabled: '%s'", svc->name);
return svc;
}
static void write_to_child(int out, const unsigned char *buf, ssize_t len, const char *prog_name)
{
if (write_in_full(out, buf, len) < 0)
die("unable to write to '%s'", prog_name);
}
/*
* This is basically strbuf_read(), except that if we
* hit max_request_buffer we die (we'd rather reject a
* maliciously large request than chew up infinite memory).
*/
static ssize_t read_request_eof(int fd, unsigned char **out)
{
size_t len = 0, alloc = 8192;
unsigned char *buf = xmalloc(alloc);
if (max_request_buffer < alloc)
max_request_buffer = alloc;
while (1) {
ssize_t cnt;
cnt = read_in_full(fd, buf + len, alloc - len);
if (cnt < 0) {
free(buf);
return -1;
}
/* partial read from read_in_full means we hit EOF */
len += cnt;
if (len < alloc) {
*out = buf;
return len;
}
/* otherwise, grow and try again (if we can) */
if (alloc == max_request_buffer)
die("request was larger than our maximum size (%lu);"
" try setting GIT_HTTP_MAX_REQUEST_BUFFER",
max_request_buffer);
alloc = alloc_nr(alloc);
if (alloc > max_request_buffer)
alloc = max_request_buffer;
REALLOC_ARRAY(buf, alloc);
}
}
static ssize_t read_request_fixed_len(int fd, ssize_t req_len, unsigned char **out)
{
unsigned char *buf = NULL;
ssize_t cnt = 0;
if (max_request_buffer < req_len) {
die("request was larger than our maximum size (%lu): "
"%" PRIuMAX "; try setting GIT_HTTP_MAX_REQUEST_BUFFER",
max_request_buffer, (uintmax_t)req_len);
}
buf = xmalloc(req_len);
cnt = read_in_full(fd, buf, req_len);
if (cnt < 0) {
free(buf);
return -1;
}
*out = buf;
return cnt;
}
static ssize_t get_content_length(void)
{
ssize_t val = -1;
const char *str = getenv("CONTENT_LENGTH");
if (str && *str && !git_parse_ssize_t(str, &val))
die("failed to parse CONTENT_LENGTH: %s", str);
return val;
}
static ssize_t read_request(int fd, unsigned char **out, ssize_t req_len)
{
if (req_len < 0)
return read_request_eof(fd, out);
else
return read_request_fixed_len(fd, req_len, out);
}
static void inflate_request(const char *prog_name, int out, int buffer_input, ssize_t req_len)
{
git_zstream stream;
unsigned char *full_request = NULL;
unsigned char in_buf[8192];
unsigned char out_buf[8192];
unsigned long cnt = 0;
int req_len_defined = req_len >= 0;
size_t req_remaining_len = req_len;
memset(&stream, 0, sizeof(stream));
git_inflate_init_gzip_only(&stream);
while (1) {
ssize_t n;
if (buffer_input) {
if (full_request)
n = 0; /* nothing left to read */
else
n = read_request(0, &full_request, req_len);
stream.next_in = full_request;
} else {
ssize_t buffer_len;
if (req_len_defined && req_remaining_len <= sizeof(in_buf))
buffer_len = req_remaining_len;
else
buffer_len = sizeof(in_buf);
n = xread(0, in_buf, buffer_len);
stream.next_in = in_buf;
if (req_len_defined && n > 0)
req_remaining_len -= n;
}
if (n <= 0)
die("request ended in the middle of the gzip stream");
stream.avail_in = n;
while (0 < stream.avail_in) {
int ret;
stream.next_out = out_buf;
stream.avail_out = sizeof(out_buf);
ret = git_inflate(&stream, Z_NO_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END)
die("zlib error inflating request, result %d", ret);
n = stream.total_out - cnt;
write_to_child(out, out_buf, stream.total_out - cnt, prog_name);
cnt = stream.total_out;
if (ret == Z_STREAM_END)
goto done;
}
}
done:
git_inflate_end(&stream);
close(out);
free(full_request);
}
static void copy_request(const char *prog_name, int out, ssize_t req_len)
{
unsigned char *buf;
ssize_t n = read_request(0, &buf, req_len);
if (n < 0)
die_errno("error reading request body");
write_to_child(out, buf, n, prog_name);
close(out);
free(buf);
}
static void pipe_fixed_length(const char *prog_name, int out, size_t req_len)
{
unsigned char buf[8192];
size_t remaining_len = req_len;
while (remaining_len > 0) {
size_t chunk_length = remaining_len > sizeof(buf) ? sizeof(buf) : remaining_len;
ssize_t n = xread(0, buf, chunk_length);
if (n < 0)
die_errno("Reading request failed");
write_to_child(out, buf, n, prog_name);
remaining_len -= n;
}
close(out);
}
static void run_service(const char **argv, int buffer_input)
{
const char *encoding = getenv("HTTP_CONTENT_ENCODING");
const char *user = getenv("REMOTE_USER");
const char *host = getenv("REMOTE_ADDR");
int gzipped_request = 0;
struct child_process cld = CHILD_PROCESS_INIT;
ssize_t req_len = get_content_length();
if (encoding && (!strcmp(encoding, "gzip") || !strcmp(encoding, "x-gzip")))
gzipped_request = 1;
if (!user || !*user)
user = "anonymous";
if (!host || !*host)
host = "(none)";
if (!getenv("GIT_COMMITTER_NAME"))
strvec_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
if (!getenv("GIT_COMMITTER_EMAIL"))
strvec_pushf(&cld.env_array,
"GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
strvec_pushv(&cld.args, argv);
if (buffer_input || gzipped_request || req_len >= 0)
cld.in = -1;
cld.git_cmd = 1;
cld.clean_on_exit = 1;
cld.wait_after_clean = 1;
if (start_command(&cld))
exit(1);
close(1);
if (gzipped_request)
inflate_request(argv[0], cld.in, buffer_input, req_len);
else if (buffer_input)
copy_request(argv[0], cld.in, req_len);
else if (req_len >= 0)
pipe_fixed_length(argv[0], cld.in, req_len);
else
close(0);
if (finish_command(&cld))
exit(1);
}
static int show_text_ref(const char *name, const struct object_id *oid,
int flag, void *cb_data)
{
const char *name_nons = strip_namespace(name);
struct strbuf *buf = cb_data;
struct object *o = parse_object(the_repository, oid);
if (!o)
return 0;
strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
if (o->type == OBJ_TAG) {
o = deref_tag(the_repository, o, name, 0);
if (!o)
return 0;
strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
name_nons);
}
return 0;
}
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);
if (service_name) {
const char *argv[] = {NULL /* service name */,
"--http-backend-info-refs",
".", NULL};
struct rpc_service *svc = select_service(hdr, service_name);
strbuf_addf(&buf, "application/x-git-%s-advertisement",
svc->name);
hdr_str(hdr, content_type, buf.buf);
end_headers(hdr);
if (determine_protocol_version_server() != protocol_v2) {
packet_write_fmt(1, "# service=git-%s\n", svc->name);
packet_flush(1);
}
argv[0] = svc->name;
run_service(argv, 0);
} else {
select_getanyfile(hdr);
for_each_namespaced_ref(show_text_ref, &buf);
send_strbuf(hdr, "text/plain", &buf);
}
strbuf_release(&buf);
}
static int show_head_ref(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
struct strbuf *buf = cb_data;
if (flag & REF_ISSYMREF) {
const char *target = resolve_ref_unsafe(refname,
RESOLVE_REF_READING,
NULL, NULL);
if (target)
strbuf_addf(buf, "ref: %s\n", strip_namespace(target));
} else {
strbuf_addf(buf, "%s\n", oid_to_hex(oid));
}
return 0;
}
static void get_head(struct strbuf *hdr, char *arg)
{
struct strbuf buf = STRBUF_INIT;
select_getanyfile(hdr);
head_ref_namespaced(show_head_ref, &buf);
send_strbuf(hdr, "text/plain", &buf);
strbuf_release(&buf);
}
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(hdr);
for (p = get_all_packs(the_repository); p; p = p->next) {
if (p->pack_local)
cnt++;
}
strbuf_grow(&buf, cnt * 53 + 2);
for (p = get_all_packs(the_repository); 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(hdr);
send_strbuf(hdr, "text/plain; charset=utf-8", &buf);
strbuf_release(&buf);
}
static void check_content_type(struct strbuf *hdr, const char *accepted_type)
{
const char *actual_type = getenv("CONTENT_TYPE");
if (!actual_type)
actual_type = "";
if (strcmp(actual_type, accepted_type)) {
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",
accepted_type, actual_type);
exit(0);
}
}
static void service_rpc(struct strbuf *hdr, char *service_name)
{
const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
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(hdr, buf.buf);
hdr_nocache(hdr);
strbuf_reset(&buf);
strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
hdr_str(hdr, content_type, buf.buf);
end_headers(hdr);
argv[0] = svc->name;
run_service(argv, svc->buffer_input);
strbuf_release(&buf);
}
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(&hdr, 500, "Internal Server Error");
hdr_nocache(&hdr);
end_headers(&hdr);
}
exit(0); /* we successfully reported a failure ;-) */
}
static int die_webcgi_recursing(void)
{
return dead++ > 1;
}
static char* getdir(void)
{
struct strbuf buf = STRBUF_INIT;
char *pathinfo = getenv("PATH_INFO");
char *root = getenv("GIT_PROJECT_ROOT");
char *path = getenv("PATH_TRANSLATED");
if (root && *root) {
if (!pathinfo || !*pathinfo)
die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
if (daemon_avoid_alias(pathinfo))
die("'%s': aliased", pathinfo);
end_url_with_slash(&buf, root);
if (pathinfo[0] == '/')
pathinfo++;
strbuf_addstr(&buf, pathinfo);
return strbuf_detach(&buf, NULL);
} else if (path && *path) {
return xstrdup(path);
} else
die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
return NULL;
}
static struct service_cmd {
const char *method;
const char *pattern;
void (*imp)(struct strbuf *, 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/[0-9a-f]{2}/[0-9a-f]{62}$", get_loose_object},
{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
{"GET", "/objects/pack/pack-[0-9a-f]{64}\\.pack$", get_pack_file},
{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
{"GET", "/objects/pack/pack-[0-9a-f]{64}\\.idx$", get_idx_file},
{"POST", "/git-upload-pack$", service_rpc},
{"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");
const char *proto_header;
char *dir;
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);
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))
return bad_request(&hdr, c);
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(&hdr, "Request not supported: '%s'", dir);
setup_path();
if (!enter_repo(dir, 0))
not_found(&hdr, "Not a git repository: '%s'", dir);
if (!getenv("GIT_HTTP_EXPORT_ALL") &&
access("git-daemon-export-ok", F_OK) )
not_found(&hdr, "Repository not exported: '%s'", dir);
http_config();
max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
max_request_buffer);
proto_header = getenv("HTTP_GIT_PROTOCOL");
if (proto_header)
setenv(GIT_PROTOCOL_ENVIRONMENT, proto_header, 0);
cmd->imp(&hdr, cmd_arg);
return 0;
}