[or-cvs] r16722: {tor} Add a lockfile to the Tor data directory to avoid situations (in tor/trunk: . src/common src/or)
nickm at seul.org
nickm at seul.org
Mon Sep 1 20:06:26 UTC 2008
Author: nickm
Date: 2008-09-01 16:06:26 -0400 (Mon, 01 Sep 2008)
New Revision: 16722
Modified:
tor/trunk/ChangeLog
tor/trunk/configure.in
tor/trunk/src/common/compat.c
tor/trunk/src/common/compat.h
tor/trunk/src/or/config.c
tor/trunk/src/or/main.c
tor/trunk/src/or/or.h
tor/trunk/src/or/router.c
Log:
Add a lockfile to the Tor data directory to avoid situations where two Tors start with the same datadir, or where a --list-fingerprints races with a server to create keys, or such.
Modified: tor/trunk/ChangeLog
===================================================================
--- tor/trunk/ChangeLog 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/ChangeLog 2008-09-01 20:06:26 UTC (rev 16722)
@@ -3,7 +3,11 @@
- Fix compile on OpenBSD 4.4-current. Bugfix on 0.2.1.5-alpha.
Reported by Tas.
+ o Minor features:
+ - Use a lockfile to make sure that two Tor processes are not
+ simultaneously running with the same datadir.
+
Changes in version 0.2.1.5-alpha - 2008-08-31
o Major features:
- Convert many internal address representations to optionally hold
Modified: tor/trunk/configure.in
===================================================================
--- tor/trunk/configure.in 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/configure.in 2008-09-01 20:06:26 UTC (rev 16722)
@@ -324,7 +324,7 @@
dnl These headers are not essential
-AC_CHECK_HEADERS(stdint.h sys/types.h inttypes.h sys/param.h sys/wait.h limits.h sys/limits.h netinet/in.h arpa/inet.h machine/limits.h syslog.h sys/time.h sys/resource.h inttypes.h utime.h sys/utime.h sys/mman.h netinet/in6.h malloc.h sys/syslimits.h malloc/malloc.h linux/types.h)
+AC_CHECK_HEADERS(stdint.h sys/types.h inttypes.h sys/param.h sys/wait.h limits.h sys/limits.h netinet/in.h arpa/inet.h machine/limits.h syslog.h sys/time.h sys/resource.h inttypes.h utime.h sys/utime.h sys/mman.h netinet/in6.h malloc.h sys/syslimits.h malloc/malloc.h linux/types.h sys/file.h)
TOR_CHECK_PROTOTYPE(malloc_good_size, HAVE_MALLOC_GOOD_SIZE_PROTOTYPE,
[#ifdef HAVE_MALLOC_H
Modified: tor/trunk/src/common/compat.c
===================================================================
--- tor/trunk/src/common/compat.c 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/src/common/compat.c 2008-09-01 20:06:26 UTC (rev 16722)
@@ -26,6 +26,7 @@
#ifdef MS_WINDOWS
#include <process.h>
#include <windows.h>
+#include <sys/locking.h>
#endif
#ifdef HAVE_UNAME
@@ -98,6 +99,9 @@
#ifdef HAVE_SYS_SYSLIMITS_H
#include <sys/syslimits.h>
#endif
+#ifdef HAVE_SYS_FILE_H
+#include <sys/file.h>
+#endif
#ifdef USE_BSOCKETS
#include <bsocket.h>
@@ -488,6 +492,77 @@
return 0;
}
+struct tor_lockfile_t {
+ char *filename;
+ int fd;
+};
+
+tor_lockfile_t *
+tor_lockfile_lock(const char *filename, int blocking, int *locked_out)
+{
+ tor_lockfile_t *result;
+ int fd;
+ *locked_out = 0;
+
+ log_info(LD_FS, "Locking \"%s\"", filename);
+ fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0600);
+ if (fd < 0) {
+ log_warn(LD_FS,"Couldn't open \"%s\" for locking: %s", filename,
+ strerror(errno));
+ return NULL;
+ }
+#ifdef WIN32
+ _lseek(fd, 0, SEEK_SET);
+ if (_locking(fd, blocking ? _LK_LOCK : _LK_NBLOCK, 0) < 0) {
+ if (errno != EDEADLOCK)
+ log_warn(LD_FS,"Couldn't lock \"%s\": %s", filename, strerror(errno));
+ else
+ *locked_out = 1;
+ close(fd);
+ return NULL;
+ }
+#else
+ if (flock(fd, LOCK_EX|(blocking ? 0 : LOCK_NB)) < 0) {
+ if (errno != EWOULDBLOCK)
+ log_warn(LD_FS,"Couldn't lock \"%s\": %s", filename, strerror(errno));
+ else
+ *locked_out = 1;
+ close(fd);
+ return NULL;
+ }
+#endif
+
+ result = tor_malloc(sizeof(tor_lockfile_t));
+ result->filename = tor_strdup(filename);
+ result->fd = fd;
+ return result;
+}
+
+void
+tor_lockfile_unlock(tor_lockfile_t *lockfile)
+{
+ tor_assert(lockfile);
+
+ log_info(LD_FS, "Unlocking \"%s\"", lockfile->filename);
+#ifdef WIN32
+ _lseek(fd, 0, SEEK_SET);
+ if (_locking(fd, _LK_UNLCK, 0) < 0) {
+ log_warn(LD_FS,"Error unlocking \"%s\": %s", lockfile->filename,
+ strerror(errno));
+ }
+#else
+ if (flock(lockfile->fd, LOCK_UN) < 0) {
+ log_warn(LD_FS, "Error unlocking \"%s\": %s", lockfile->filename,
+ strerror(errno));
+ }
+#endif
+
+ close(lockfile->fd);
+ lockfile->fd = -1;
+ tor_free(lockfile->filename);
+ tor_free(lockfile);
+}
+
#undef DEBUG_SOCKET_COUNTING
#ifdef DEBUG_SOCKET_COUNTING
/** A bitarray of all fds that should be passed to tor_socket_close(). Only
Modified: tor/trunk/src/common/compat.h
===================================================================
--- tor/trunk/src/common/compat.h 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/src/common/compat.h 2008-09-01 20:06:26 UTC (rev 16722)
@@ -266,6 +266,11 @@
int replace_file(const char *from, const char *to);
int touch_file(const char *fname);
+typedef struct tor_lockfile_t tor_lockfile_t;
+tor_lockfile_t *tor_lockfile_lock(const char *filename, int blocking,
+ int *locked_out);
+void tor_lockfile_unlock(tor_lockfile_t *lockfile);
+
#ifdef MS_WINDOWS
#define PATH_SEPARATOR "\\"
#else
Modified: tor/trunk/src/or/config.c
===================================================================
--- tor/trunk/src/or/config.c 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/src/or/config.c 2008-09-01 20:06:26 UTC (rev 16722)
@@ -1172,6 +1172,11 @@
int running_tor = options->command == CMD_RUN_TOR;
char *msg;
+ if (running_tor && !have_lockfile()) {
+ if (try_locking(options, 1) < 0)
+ return -1;
+ }
+
if (consider_adding_dir_authorities(options, old_options) < 0)
return -1;
@@ -4883,10 +4888,10 @@
* Note: Consider using the get_datadir_fname* macros in or.h.
*/
char *
-get_datadir_fname2_suffix(const char *sub1, const char *sub2,
- const char *suffix)
+options_get_datadir_fname2_suffix(or_options_t *options,
+ const char *sub1, const char *sub2,
+ const char *suffix)
{
- or_options_t *options = get_options();
char *fname = NULL;
size_t len;
tor_assert(options);
Modified: tor/trunk/src/or/main.c
===================================================================
--- tor/trunk/src/or/main.c 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/src/or/main.c 2008-09-01 20:06:26 UTC (rev 16722)
@@ -1850,6 +1850,54 @@
return 0;
}
+static tor_lockfile_t *lockfile = NULL;
+
+int
+try_locking(or_options_t *options, int err_if_locked)
+{
+ if (lockfile)
+ return 0;
+ else {
+ char *fname = options_get_datadir_fname2_suffix(options, "lock",NULL,NULL);
+ int already_locked = 0;
+ tor_lockfile_t *lf = tor_lockfile_lock(fname, 0, &already_locked);
+ tor_free(fname);
+ if (!lf) {
+ if (err_if_locked && already_locked) {
+ int r;
+ log_warn(LD_GENERAL, "It looks like another Tor process is running "
+ "with the same data directory. Waiting 5 seconds to see "
+ "if it goes away.");
+ sleep(5);
+ r = try_locking(options, 0);
+ if (r<0) {
+ log_err(LD_GENERAL, "No, it's still there. Exiting.");
+ exit(0);
+ }
+ return r;
+ }
+ return -1;
+ }
+ lockfile = lf;
+ return 0;
+ }
+}
+
+int
+have_lockfile(void)
+{
+ return lockfile != NULL;
+}
+
+void
+release_lockfile(void)
+{
+ if (lockfile) {
+ tor_lockfile_unlock(lockfile);
+ lockfile = NULL;
+ }
+}
+
/** Free all memory that we might have allocated somewhere.
* If <b>postfork</b>, we are a worker process and we want to free
* only the parts of memory that we won't touch. If !<b>postfork</b>,
Modified: tor/trunk/src/or/or.h
===================================================================
--- tor/trunk/src/or/or.h 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/src/or/or.h 2008-09-01 20:06:26 UTC (rev 16722)
@@ -2781,8 +2781,11 @@
const char *key);
int options_save_current(void);
const char *get_torrc_fname(void);
-char *get_datadir_fname2_suffix(const char *sub1, const char *sub2,
- const char *suffix);
+char *options_get_datadir_fname2_suffix(or_options_t *options,
+ const char *sub1, const char *sub2,
+ const char *suffix);
+#define get_datadir_fname2_suffix(sub1, sub2, suffix) \
+ options_get_datadir_fname2_suffix(get_options(), (sub1), (sub2), (suffix))
/** Return a newly allocated string containing datadir/sub1. See
* get_datadir_fname2_suffix. */
#define get_datadir_fname(sub1) get_datadir_fname2_suffix((sub1), NULL, NULL)
@@ -3493,6 +3496,11 @@
void control_signal_act(int the_signal);
void handle_signals(int is_parent);
+
+int try_locking(or_options_t *options, int err_if_locked);
+int have_lockfile(void);
+void release_lockfile(void);
+
void tor_cleanup(void);
void tor_free_all(int postfork);
Modified: tor/trunk/src/or/router.c
===================================================================
--- tor/trunk/src/or/router.c 2008-09-01 19:15:05 UTC (rev 16721)
+++ tor/trunk/src/or/router.c 2008-09-01 20:06:26 UTC (rev 16722)
@@ -235,6 +235,17 @@
goto error;
case FN_NOENT:
if (generate) {
+ if (!have_lockfile()) {
+ if (try_locking(get_options(), 0)<0) {
+ /* Make sure that --list-fingerprint only creates new keys
+ * if there is no possibility for a deadlock. */
+ log(severity, LD_FS, "Another Tor process has locked \"%s\". Not "
+ "writing any new keys.", fname);
+ /*XXXX The 'other process' might make a key in a second or two;
+ * maybe we should wait for it. */
+ goto error;
+ }
+ }
log_info(LD_GENERAL, "No key found in \"%s\"; generating fresh key.",
fname);
if (crypto_pk_generate_key(prkey)) {
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