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#include "cache.h"

#include "credential.h"

#include "unix-socket.h"

#include "sigchain.h"

static const char *socket_path;

static void cleanup_socket(void)

{

if (socket_path)

unlink(socket_path);

}

static void cleanup_socket_on_signal(int sig)

{

cleanup_socket();

sigchain_pop(sig);

raise(sig);

}

struct credential_cache_entry {

struct credential item;

unsigned long expiration;

};

static struct credential_cache_entry *entries;

static int entries_nr;

static int entries_alloc;

static void cache_credential(struct credential *c, int timeout)

{

struct credential_cache_entry *e;

ALLOC_GROW(entries, entries_nr + 1, entries_alloc);

e = &entries[entries_nr++];

/* take ownership of pointers */

memcpy(&e->item, c, sizeof(*c));

memset(c, 0, sizeof(*c));

e->expiration = time(NULL) + timeout;

}

static struct credential_cache_entry *lookup_credential(const struct credential *c)

{

int i;

for (i = 0; i < entries_nr; i++) {

struct credential *e = &entries[i].item;

if (credential_match(c, e))

return &entries[i];

}

return NULL;

}

static void remove_credential(const struct credential *c)

{

struct credential_cache_entry *e;

e = lookup_credential(c);

if (e)

e->expiration = 0;

}

static int check_expirations(void)

{

static unsigned long wait_for_entry_until;

int i = 0;

unsigned long now = time(NULL);

unsigned long next = (unsigned long)-1;

/*

* Initially give the client 30 seconds to actually contact us

* and store a credential before we decide there's no point in

* keeping the daemon around.

*/

if (!wait_for_entry_until)

wait_for_entry_until = now + 30;

while (i < entries_nr) {

if (entries[i].expiration <= now) {

entries_nr--;

credential_clear(&entries[i].item);

if (i != entries_nr)

memcpy(&entries[i], &entries[entries_nr], sizeof(*entries));

/*

* Stick around 30 seconds in case a new credential

* shows up (e.g., because we just removed a failed

* one, and we will soon get the correct one).

*/

wait_for_entry_until = now + 30;

}

else {

if (entries[i].expiration < next)

next = entries[i].expiration;

i++;

}

}

if (!entries_nr) {

if (wait_for_entry_until <= now)

return 0;

next = wait_for_entry_until;

}

return next - now;

}

static int read_request(FILE *fh, struct credential *c,

struct strbuf *action, int *timeout) {

static struct strbuf item = STRBUF_INIT;

const char *p;

strbuf_getline(&item, fh, '\n');

p = skip_prefix(item.buf, "action=");

if (!p)

return error("client sent bogus action line: %s", item.buf);

strbuf_addstr(action, p);

strbuf_getline(&item, fh, '\n');

p = skip_prefix(item.buf, "timeout=");

if (!p)

return error("client sent bogus timeout line: %s", item.buf);

*timeout = atoi(p);

if (credential_read(c, fh) < 0)

return -1;

return 0;

}

static void serve_one_client(FILE *in, FILE *out)

{

struct credential c = CREDENTIAL_INIT;

struct strbuf action = STRBUF_INIT;

int timeout = -1;

if (read_request(in, &c, &action, &timeout) < 0)

/* ignore error */ ;

else if (!strcmp(action.buf, "get")) {

struct credential_cache_entry *e = lookup_credential(&c);

if (e) {

fprintf(out, "username=%s\n", e->item.username);

fprintf(out, "password=%s\n", e->item.password);

}

}

else if (!strcmp(action.buf, "exit"))

exit(0);

else if (!strcmp(action.buf, "erase"))

remove_credential(&c);

else if (!strcmp(action.buf, "store")) {

if (timeout < 0)

warning("cache client didn't specify a timeout");

else if (!c.username || !c.password)

warning("cache client gave us a partial credential");

else {

remove_credential(&c);

cache_credential(&c, timeout);

}

}

else

warning("cache client sent unknown action: %s", action.buf);

credential_clear(&c);

strbuf_release(&action);

}

static int serve_cache_loop(int fd)

{

struct pollfd pfd;

unsigned long wakeup;

wakeup = check_expirations();

if (!wakeup)

return 0;

pfd.fd = fd;

pfd.events = POLLIN;

if (poll(&pfd, 1, 1000 * wakeup) < 0) {

if (errno != EINTR)

die_errno("poll failed");

return 1;

}

if (pfd.revents & POLLIN) {

int client, client2;

FILE *in, *out;

client = accept(fd, NULL, NULL);

if (client < 0) {

warning("accept failed: %s", strerror(errno));

return 1;

}

client2 = dup(client);

if (client2 < 0) {

warning("dup failed: %s", strerror(errno));

close(client);

return 1;

}

in = xfdopen(client, "r");

out = xfdopen(client2, "w");

serve_one_client(in, out);

fclose(in);

fclose(out);

}

return 1;

}

static void serve_cache(const char *socket_path)

{

int fd;

fd = unix_stream_listen(socket_path);

if (fd < 0)

die_errno("unable to bind to '%s'", socket_path);

printf("ok\n");

fclose(stdout);

while (serve_cache_loop(fd))

; /* nothing */

close(fd);

unlink(socket_path);

}

static const char permissions_advice[] =

"The permissions on your socket directory are too loose; other\n"

"users may be able to read your cached credentials. Consider running:\n"

"\n"

" chmod 0700 %s";

static void check_socket_directory(const char *path)

{

struct stat st;

char *path_copy = xstrdup(path);

char *dir = dirname(path_copy);

if (!stat(dir, &st)) {

if (st.st_mode & 077)

die(permissions_advice, dir);

free(path_copy);

return;

}

/*

* We must be sure to create the directory with the correct mode,

* not just chmod it after the fact; otherwise, there is a race

* condition in which somebody can chdir to it, sleep, then try to open

* our protected socket.

*/

if (safe_create_leading_directories_const(dir) < 0)

die_errno("unable to create directories for '%s'", dir);

if (mkdir(dir, 0700) < 0)

die_errno("unable to mkdir '%s'", dir);

free(path_copy);

}

int main(int argc, const char **argv)

{

socket_path = argv[1];

if (!socket_path)

die("usage: git-credential-cache--daemon <socket_path>");

check_socket_directory(socket_path);

atexit(cleanup_socket);

sigchain_push_common(cleanup_socket_on_signal);

serve_cache(socket_path);

return 0;

}