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Use a POSIX lock for pkgdb and only issue pkgdb writes in exact points.

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- Rather than using a POSIX named semaphore use a POSIX lock (lockf(3))
for pkgdb for writers. Writers that cannot acquire the pkgdb lock will
get EAGAIN rather then being blocked.

- Due to using a file lock we cannot write the pkgdb every time a package
is being unpacked, configured or removed. Instead pkgdb is only written
at the end of a specific point in the transaction (unpack, configure, remove)
or via xbps_pkgdb_unlock().
This commit is contained in:
Juan RP 2014-03-04 14:37:10 +01:00
parent 6335573180
commit 0416b067d0
11 changed files with 85 additions and 101 deletions
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5
NEWS
View File

@ -8,6 +8,9 @@ xbps-0.33 (???):
the output file will be named "bar.tar.gz". Contributed by
Enno Boland (Gottox).
* Rather than performing a pkgdb write per package being unpacked, configured,
or removed, issue the write only once after the transaction phase has finished.
* While checking file permissions for package files removal, make sure
to not dereference symbolic links, because a symlink might point to
a file in the rootfs, which won't have the same uid/gid.
@ -20,7 +23,7 @@ xbps-0.33 (???):
* Only allow a single writer to the pkgdb to avoid concurrency issues
when performing multiple write transactions (install, update or remove).
The implementation relies on a POSIX named semaphore.
Processes that cannot acquire the lock will get an EAGAIN error.
* Do not continue the transaction if downloading a binpkg/signature file
has failed for some reason, stop and return error immediately.

19
bin/xbps-pkgdb/check.c
View File

@ -1,5 +1,5 @@
/*-
* Copyright (c) 2009-2013 Juan Romero Pardines.
* Copyright (c) 2009-2014 Juan Romero Pardines.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -64,19 +64,7 @@ pkgdb_cb(struct xbps_handle *xhp _unused,
int
check_pkg_integrity_all(struct xbps_handle *xhp)
{
int rv;
/* force an update to get total pkg count */
(void)xbps_pkgdb_update(xhp, false);
rv = xbps_pkgdb_foreach_cb_multi(xhp, pkgdb_cb, NULL);
if ((rv = xbps_pkgdb_update(xhp, true)) != 0) {
xbps_error_printf("failed to write pkgdb: %s\n",
strerror(rv));
return rv;
}
return 0;
return xbps_pkgdb_foreach_cb_multi(xhp, pkgdb_cb, NULL);
}
int
@ -151,8 +139,5 @@ do { \
#undef RUN_PKG_CHECK
if ((rv == 0) && (pkgd == NULL))
(void)xbps_pkgdb_update(xhp, true);
return 0;
}

2
bin/xbps-pkgdb/main.c
View File

@ -72,7 +72,7 @@ change_pkg_mode(struct xbps_handle *xhp, const char *pkgname, const char *mode)
else
usage(true);
return xbps_pkgdb_update(xhp, true);
return 0;
}
int

25
bin/xbps-reconfigure/main.c
View File

@ -153,17 +153,22 @@ main(int argc, char **argv)
exit(EXIT_FAILURE);
}
if (all) {
rv = xbps_configure_packages(&xh, true);
} else {
for (i = optind; i < argc; i++) {
rv = xbps_configure_pkg(&xh, argv[i],
true, false, true);
if (rv != 0)
fprintf(stderr, "Failed to reconfigure "
"`%s': %s\n", argv[i], strerror(rv));
}
if ((rv = xbps_pkgdb_lock(&xh)) != 0) {
fprintf(stderr, "failed to lock pkgdb: %s\n", strerror(rv));
exit(EXIT_FAILURE);
}
if (all) {
rv = xbps_configure_packages(&xh);
} else {
for (i = optind; i < argc; i++) {
rv = xbps_configure_pkg(&xh, argv[i], true, false);
if (rv != 0) {
fprintf(stderr, "Failed to reconfigure "
"`%s': %s\n", argv[i], strerror(rv));
}
}
}
xbps_pkgdb_unlock(&xh);
exit(rv ? EXIT_FAILURE : EXIT_SUCCESS);
}

21
include/xbps.h.in
View File

@ -29,8 +29,6 @@
#include <stdio.h>
#include <inttypes.h>
#include <limits.h>
#include <semaphore.h>
#include <xbps/xbps_array.h>
#include <xbps/xbps_bool.h>
@ -50,7 +48,7 @@
*
* This header documents the full API for the XBPS Library.
*/
#define XBPS_API_VERSION "20140225"
#define XBPS_API_VERSION "20140304"
#ifndef XBPS_VERSION
#define XBPS_VERSION "UNSET"
@ -471,11 +469,11 @@ struct xbps_handle {
*/
xbps_dictionary_t pkgdb;
/**
* @private
* @var pkgdb_plist;
*
* POSIX named semaphore associated with the pkgdb for writers.
* Absolute pathname to the pkgdb plist file.
*/
sem_t *pkgdb_sem;
char *pkgdb_plist;
/**
* @var transd
*
@ -632,25 +630,20 @@ void xbps_end(struct xbps_handle *xhp);
* @param[in] check_state Set it to true to check that package is
* in unpacked state.
* @param[in] update Set it to true if this package is being updated.
* @param[in] flush Set it to true to flush state to pkgdb.
*
* @return 0 on success, otherwise an errno value.
*/
int xbps_configure_pkg(struct xbps_handle *xhp,
const char *pkgname,
bool check_state,
bool update,
bool flush);
int xbps_configure_pkg(struct xbps_handle *xhp, const char *pkgname,
bool check_state, bool update);
/**
* Configure (or force reconfiguration of) all packages.
*
* @param[in] xhp Pointer to an xbps_handle struct.
* @param[in] flush Set it to true to flush state to pkgdb.
*
* @return 0 on success, otherwise an errno value.
*/
int xbps_configure_packages(struct xbps_handle *xhp, bool flush);
int xbps_configure_packages(struct xbps_handle *xhp);
/*@}*/

4
lib/initend.c
View File

@ -368,10 +368,6 @@ xbps_end(struct xbps_handle *xhp)
assert(xhp);
xbps_pkgdb_release(xhp);
if (xbps_object_type(xhp->pkgdb_revdeps) != XBPS_TYPE_UNKNOWN)
xbps_object_release(xhp->pkgdb_revdeps);
xbps_fetch_unset_cache_connection();
}

19
lib/package_configure.c
View File

@ -1,5 +1,5 @@
/*-
* Copyright (c) 2009-2013 Juan Romero Pardines.
* Copyright (c) 2009-2014 Juan Romero Pardines.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -46,7 +46,7 @@
* state is XBPS_PKG_STATE_INSTALLED.
*/
int
xbps_configure_packages(struct xbps_handle *xhp, bool flush)
xbps_configure_packages(struct xbps_handle *xhp)
{
xbps_dictionary_t pkgd;
xbps_object_t obj;
@ -62,7 +62,7 @@ xbps_configure_packages(struct xbps_handle *xhp, bool flush)
while ((obj = xbps_object_iterator_next(iter))) {
pkgd = xbps_dictionary_get_keysym(xhp->pkgdb, obj);
xbps_dictionary_get_cstring_nocopy(pkgd, "pkgver", &pkgver);
rv = xbps_configure_pkg(xhp, pkgver, true, false, false);
rv = xbps_configure_pkg(xhp, pkgver, true, false);
if (rv != 0) {
xbps_dbg_printf(xhp, "%s: failed to configure %s: %s\n",
__func__, pkgver, strerror(rv));
@ -71,9 +71,6 @@ xbps_configure_packages(struct xbps_handle *xhp, bool flush)
}
xbps_object_iterator_release(iter);
if ((rv == 0) && flush)
rv = xbps_pkgdb_update(xhp, true);
return rv;
}
@ -81,8 +78,7 @@ int
xbps_configure_pkg(struct xbps_handle *xhp,
const char *pkgver,
bool check_state,
bool update,
bool flush)
bool update)
{
xbps_dictionary_t pkgd, pkgmetad;
char *pkgname, *plist;
@ -154,13 +150,6 @@ xbps_configure_pkg(struct xbps_handle *xhp,
pkgver, strerror(rv));
return rv;
}
if (flush) {
if ((rv = xbps_pkgdb_update(xhp, true)) != 0) {
xbps_set_cb_state(xhp, XBPS_STATE_CONFIGURE_FAIL, rv,
pkgver, "%s: [configure] failed to update pkgdb: %s\n",
pkgver, strerror(rv));
}
}
xbps_object_release(pkgmetad);
if (rv == 0)

5
lib/package_register.c
View File

@ -1,5 +1,5 @@
/*-
* Copyright (c) 2008-2013 Juan Romero Pardines.
* Copyright (c) 2008-2014 Juan Romero Pardines.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -140,10 +140,7 @@ xbps_register_pkg(struct xbps_handle *xhp, xbps_dictionary_t pkgrd)
if (!xbps_dictionary_set(xhp->pkgdb, pkgname, pkgd)) {
xbps_dbg_printf(xhp,
"%s: failed to set pkgd for %s\n", __func__, pkgver);
goto out;
}
rv = xbps_pkgdb_update(xhp, true);
out:
if (pkgname)
free(pkgname);

4
lib/package_remove.c
View File

@ -370,11 +370,7 @@ purge:
* Unregister package from pkgdb.
*/
xbps_dictionary_remove(xhp->pkgdb, pkgname);
if ((rv = xbps_pkgdb_update(xhp, true)) != 0)
goto out;
xbps_dbg_printf(xhp, "[remove] unregister %s returned %d\n", pkgver, rv);
xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_DONE, 0, pkgver, NULL);
out:
if (pkgname != NULL)

74
lib/pkgdb.c
View File

@ -57,29 +57,49 @@
* data type is specified on its edge, i.e array, bool, integer, string,
* dictionary.
*/
#define _PKGDB_SEMNAME "/libxbps-pkgdb"
static int pkgdb_fd;
int
xbps_pkgdb_lock(struct xbps_handle *xhp)
{
int rv = 0;
mode_t myumask;
int rv;
/*
* Create/open the POSIX named semaphore.
* Use a mandatory file lock to only allow one writer to pkgdb,
* other writers will block.
*/
myumask = umask(0);
xhp->pkgdb_sem = sem_open(_PKGDB_SEMNAME, O_CREAT, 0660, 1);
umask(myumask);
xhp->pkgdb_plist = xbps_xasprintf("%s/%s", xhp->metadir, XBPS_PKGDB);
if (xbps_pkgdb_init(xhp) == ENOENT) {
/* if metadir does not exist, create it */
if (access(xhp->metadir, R_OK|X_OK) == -1) {
if (errno != ENOENT)
return errno;
if (xhp->pkgdb_sem == SEM_FAILED) {
if (xbps_mkpath(xhp->metadir, 0755) == -1) {
rv = errno;
xbps_dbg_printf(xhp, "[pkgdb] failed to create metadir "
"%s: %s\n", xhp->metadir, strerror(rv));
return rv;
}
}
/* if pkgdb is unexistent, create it with an empty dictionary */
xhp->pkgdb = xbps_dictionary_create();
if (!xbps_dictionary_externalize_to_file(xhp->pkgdb, xhp->pkgdb_plist)) {
rv = errno;
xbps_dbg_printf(xhp, "[pkgdb] failed to create pkgdb "
"%s: %s\n", xhp->pkgdb_plist, strerror(rv));
return rv;
}
}
if ((pkgdb_fd = open(xhp->pkgdb_plist, O_CREAT|O_RDWR, 0664)) == -1) {
rv = errno;
xbps_dbg_printf(xhp, "pkgdb: failed to create/open named "
"semaphore: %s\n", strerror(errno));
xbps_dbg_printf(xhp, "[pkgdb] cannot open pkgdb for locking "
"%s: %s\n", xhp->pkgdb_plist, strerror(rv));
free(xhp->pkgdb_plist);
return rv;
}
if (sem_wait(xhp->pkgdb_sem) == -1) {
if (lockf(pkgdb_fd, F_TLOCK, 0) == -1) {
rv = errno;
xbps_dbg_printf(xhp, "pkgdb: failed to lock named semaphore: %s\n",
strerror(errno));
xbps_dbg_printf(xhp, "[pkgdb] cannot lock pkgdb: %s\n", strerror(rv));
return rv;
}
return 0;
@ -88,16 +108,14 @@ xbps_pkgdb_lock(struct xbps_handle *xhp)
void
xbps_pkgdb_unlock(struct xbps_handle *xhp)
{
/* Unlock semaphore, close and destroy it (if possible) */
if (xhp->pkgdb_sem == NULL)
return;
(void)xbps_pkgdb_update(xhp, true);
sem_post(xhp->pkgdb_sem);
sem_close(xhp->pkgdb_sem);
sem_unlink(_PKGDB_SEMNAME);
xhp->pkgdb_sem = NULL;
if (lockf(pkgdb_fd, F_ULOCK, 0) == -1)
xbps_dbg_printf(xhp, "[pkgdb] failed to unlock pkgdb: %s\n", strerror(errno));
(void)close(pkgdb_fd);
pkgdb_fd = -1;
}
#undef _PKGDB_SEMNAME
int HIDDEN
xbps_pkgdb_init(struct xbps_handle *xhp)
@ -125,23 +143,19 @@ int
xbps_pkgdb_update(struct xbps_handle *xhp, bool flush)
{
xbps_dictionary_t pkgdb_storage;
char *plist;
static int cached_rv;
int rv = 0;
if (cached_rv && !flush)
return cached_rv;
plist = xbps_xasprintf("%s/%s", xhp->metadir, XBPS_PKGDB);
if (xhp->pkgdb && flush) {
pkgdb_storage = xbps_dictionary_internalize_from_file(plist);
pkgdb_storage = xbps_dictionary_internalize_from_file(xhp->pkgdb_plist);
if (pkgdb_storage == NULL ||
!xbps_dictionary_equals(xhp->pkgdb, pkgdb_storage)) {
/* flush dictionary to storage */
if (!xbps_dictionary_externalize_to_file(xhp->pkgdb, plist)) {
free(plist);
if (!xbps_dictionary_externalize_to_file(xhp->pkgdb, xhp->pkgdb_plist))
return errno;
}
}
if (pkgdb_storage)
xbps_object_release(pkgdb_storage);
@ -151,7 +165,7 @@ xbps_pkgdb_update(struct xbps_handle *xhp, bool flush)
cached_rv = 0;
}
/* update copy in memory */
if ((xhp->pkgdb = xbps_dictionary_internalize_from_file(plist)) == NULL) {
if ((xhp->pkgdb = xbps_dictionary_internalize_from_file(xhp->pkgdb_plist)) == NULL) {
if (errno == ENOENT)
xhp->pkgdb = xbps_dictionary_create();
else
@ -159,7 +173,6 @@ xbps_pkgdb_update(struct xbps_handle *xhp, bool flush)
cached_rv = rv = errno;
}
free(plist);
return rv;
}
@ -172,6 +185,9 @@ xbps_pkgdb_release(struct xbps_handle *xhp)
if (xhp->pkgdb == NULL)
return;
/* write pkgdb to storage in case it was modified */
(void)xbps_pkgdb_update(xhp, true);
if (xbps_object_type(xhp->pkg_metad) == XBPS_TYPE_DICTIONARY)
xbps_object_release(xhp->pkg_metad);

8
lib/transaction_commit.c
View File

@ -265,7 +265,7 @@ xbps_transaction_commit(struct xbps_handle *xhp)
/*
* Reconfigure pending package.
*/
rv = xbps_configure_pkg(xhp, pkgver, false, false, false);
rv = xbps_configure_pkg(xhp, pkgver, false, false);
if (rv != 0)
goto out;
@ -313,6 +313,8 @@ xbps_transaction_commit(struct xbps_handle *xhp)
goto out;
xbps_object_iterator_reset(iter);
/* Force a pkgdb write for all unpacked pkgs in transaction */
(void)xbps_pkgdb_update(xhp, true);
/*
* Configure all unpacked packages.
@ -330,7 +332,7 @@ xbps_transaction_commit(struct xbps_handle *xhp)
if (strcmp(tract, "update") == 0)
update = true;
rv = xbps_configure_pkg(xhp, pkgver, false, update, true);
rv = xbps_configure_pkg(xhp, pkgver, false, update);
if (rv != 0) {
xbps_dbg_printf(xhp, "%s: configure failed for "
"%s: %s\n", __func__, pkgver, strerror(rv));
@ -351,6 +353,8 @@ xbps_transaction_commit(struct xbps_handle *xhp)
out:
xbps_object_iterator_release(iter);
/* Force a pkgdb write for all unpacked pkgs in transaction */
(void)xbps_pkgdb_update(xhp, true);
return rv;
}