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![Junio C Hamano](/assets/img/avatar_default.png)
A code clarification. * jk/credential-cache-comment-exit: credential-cache--daemon: clarify "exit" action semantics
297 lines
6.9 KiB
C
297 lines
6.9 KiB
C
#include "cache.h"
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#include "tempfile.h"
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#include "credential.h"
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#include "unix-socket.h"
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#include "parse-options.h"
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static struct tempfile socket_file;
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struct credential_cache_entry {
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struct credential item;
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unsigned long expiration;
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};
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static struct credential_cache_entry *entries;
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static int entries_nr;
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static int entries_alloc;
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static void cache_credential(struct credential *c, int timeout)
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{
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struct credential_cache_entry *e;
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ALLOC_GROW(entries, entries_nr + 1, entries_alloc);
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e = &entries[entries_nr++];
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/* take ownership of pointers */
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memcpy(&e->item, c, sizeof(*c));
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memset(c, 0, sizeof(*c));
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e->expiration = time(NULL) + timeout;
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}
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static struct credential_cache_entry *lookup_credential(const struct credential *c)
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{
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int i;
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for (i = 0; i < entries_nr; i++) {
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struct credential *e = &entries[i].item;
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if (credential_match(c, e))
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return &entries[i];
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}
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return NULL;
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}
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static void remove_credential(const struct credential *c)
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{
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struct credential_cache_entry *e;
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e = lookup_credential(c);
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if (e)
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e->expiration = 0;
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}
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static int check_expirations(void)
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{
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static unsigned long wait_for_entry_until;
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int i = 0;
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unsigned long now = time(NULL);
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unsigned long next = (unsigned long)-1;
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/*
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* Initially give the client 30 seconds to actually contact us
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* and store a credential before we decide there's no point in
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* keeping the daemon around.
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*/
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if (!wait_for_entry_until)
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wait_for_entry_until = now + 30;
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while (i < entries_nr) {
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if (entries[i].expiration <= now) {
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entries_nr--;
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credential_clear(&entries[i].item);
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if (i != entries_nr)
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memcpy(&entries[i], &entries[entries_nr], sizeof(*entries));
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/*
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* Stick around 30 seconds in case a new credential
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* shows up (e.g., because we just removed a failed
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* one, and we will soon get the correct one).
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*/
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wait_for_entry_until = now + 30;
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}
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else {
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if (entries[i].expiration < next)
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next = entries[i].expiration;
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i++;
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}
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}
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if (!entries_nr) {
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if (wait_for_entry_until <= now)
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return 0;
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next = wait_for_entry_until;
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}
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return next - now;
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}
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static int read_request(FILE *fh, struct credential *c,
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struct strbuf *action, int *timeout) {
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static struct strbuf item = STRBUF_INIT;
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const char *p;
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strbuf_getline_lf(&item, fh);
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if (!skip_prefix(item.buf, "action=", &p))
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return error("client sent bogus action line: %s", item.buf);
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strbuf_addstr(action, p);
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strbuf_getline_lf(&item, fh);
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if (!skip_prefix(item.buf, "timeout=", &p))
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return error("client sent bogus timeout line: %s", item.buf);
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*timeout = atoi(p);
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if (credential_read(c, fh) < 0)
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return -1;
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return 0;
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}
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static void serve_one_client(FILE *in, FILE *out)
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{
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struct credential c = CREDENTIAL_INIT;
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struct strbuf action = STRBUF_INIT;
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int timeout = -1;
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if (read_request(in, &c, &action, &timeout) < 0)
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/* ignore error */ ;
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else if (!strcmp(action.buf, "get")) {
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struct credential_cache_entry *e = lookup_credential(&c);
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if (e) {
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fprintf(out, "username=%s\n", e->item.username);
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fprintf(out, "password=%s\n", e->item.password);
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}
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}
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else if (!strcmp(action.buf, "exit")) {
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/*
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* It's important that we clean up our socket first, and then
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* signal the client only once we have finished the cleanup.
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* Calling exit() directly does this, because we clean up in
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* our atexit() handler, and then signal the client when our
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* process actually ends, which closes the socket and gives
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* them EOF.
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*/
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exit(0);
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}
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else if (!strcmp(action.buf, "erase"))
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remove_credential(&c);
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else if (!strcmp(action.buf, "store")) {
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if (timeout < 0)
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warning("cache client didn't specify a timeout");
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else if (!c.username || !c.password)
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warning("cache client gave us a partial credential");
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else {
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remove_credential(&c);
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cache_credential(&c, timeout);
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}
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}
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else
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warning("cache client sent unknown action: %s", action.buf);
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credential_clear(&c);
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strbuf_release(&action);
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}
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static int serve_cache_loop(int fd)
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{
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struct pollfd pfd;
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unsigned long wakeup;
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wakeup = check_expirations();
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if (!wakeup)
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return 0;
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pfd.fd = fd;
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pfd.events = POLLIN;
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if (poll(&pfd, 1, 1000 * wakeup) < 0) {
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if (errno != EINTR)
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die_errno("poll failed");
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return 1;
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}
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if (pfd.revents & POLLIN) {
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int client, client2;
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FILE *in, *out;
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client = accept(fd, NULL, NULL);
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if (client < 0) {
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warning("accept failed: %s", strerror(errno));
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return 1;
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}
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client2 = dup(client);
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if (client2 < 0) {
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warning("dup failed: %s", strerror(errno));
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close(client);
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return 1;
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}
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in = xfdopen(client, "r");
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out = xfdopen(client2, "w");
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serve_one_client(in, out);
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fclose(in);
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fclose(out);
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}
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return 1;
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}
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static void serve_cache(const char *socket_path, int debug)
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{
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int fd;
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fd = unix_stream_listen(socket_path);
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if (fd < 0)
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die_errno("unable to bind to '%s'", socket_path);
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printf("ok\n");
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fclose(stdout);
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if (!debug) {
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if (!freopen("/dev/null", "w", stderr))
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die_errno("unable to point stderr to /dev/null");
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}
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while (serve_cache_loop(fd))
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; /* nothing */
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close(fd);
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}
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static const char permissions_advice[] =
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"The permissions on your socket directory are too loose; other\n"
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"users may be able to read your cached credentials. Consider running:\n"
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"\n"
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" chmod 0700 %s";
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static void init_socket_directory(const char *path)
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{
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struct stat st;
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char *path_copy = xstrdup(path);
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char *dir = dirname(path_copy);
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if (!stat(dir, &st)) {
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if (st.st_mode & 077)
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die(permissions_advice, dir);
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} else {
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/*
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* We must be sure to create the directory with the correct mode,
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* not just chmod it after the fact; otherwise, there is a race
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* condition in which somebody can chdir to it, sleep, then try to open
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* our protected socket.
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*/
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if (safe_create_leading_directories_const(dir) < 0)
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die_errno("unable to create directories for '%s'", dir);
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if (mkdir(dir, 0700) < 0)
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die_errno("unable to mkdir '%s'", dir);
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}
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if (chdir(dir))
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/*
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* We don't actually care what our cwd is; we chdir here just to
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* be a friendly daemon and avoid tying up our original cwd.
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* If this fails, it's OK to just continue without that benefit.
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*/
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;
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free(path_copy);
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}
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int main(int argc, const char **argv)
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{
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const char *socket_path;
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int ignore_sighup = 0;
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static const char *usage[] = {
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"git-credential-cache--daemon [opts] <socket_path>",
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NULL
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};
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int debug = 0;
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const struct option options[] = {
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OPT_BOOL(0, "debug", &debug,
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N_("print debugging messages to stderr")),
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OPT_END()
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};
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git_config_get_bool("credentialcache.ignoresighup", &ignore_sighup);
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argc = parse_options(argc, argv, NULL, options, usage, 0);
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socket_path = argv[0];
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if (!socket_path)
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usage_with_options(usage, options);
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if (!is_absolute_path(socket_path))
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die("socket directory must be an absolute path");
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init_socket_directory(socket_path);
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register_tempfile(&socket_file, socket_path);
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if (ignore_sighup)
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signal(SIGHUP, SIG_IGN);
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serve_cache(socket_path, debug);
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delete_tempfile(&socket_file);
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return 0;
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}
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