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I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 6694 files FOO. I then removed trailing white space from benchtests/bench-pthread-locks.c and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this diagnostic from Savannah: remote: *** pre-commit check failed ... remote: *** error: lines with trailing whitespace found remote: error: hook declined to update refs/heads/master
502 lines
14 KiB
C
502 lines
14 KiB
C
/* Cache handling for passwd lookup.
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Copyright (C) 1998-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published
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by the Free Software Foundation; version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <https://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <errno.h>
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#include <error.h>
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#include <libintl.h>
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#include <pwd.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/socket.h>
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#include <stackinfo.h>
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#include <scratch_buffer.h>
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#include "nscd.h"
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#include "dbg_log.h"
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/* This is the standard reply in case the service is disabled. */
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static const pw_response_header disabled =
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{
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.version = NSCD_VERSION,
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.found = -1,
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.pw_name_len = 0,
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.pw_passwd_len = 0,
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.pw_uid = -1,
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.pw_gid = -1,
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.pw_gecos_len = 0,
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.pw_dir_len = 0,
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.pw_shell_len = 0
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};
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/* This is the struct describing how to write this record. */
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const struct iovec pwd_iov_disabled =
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{
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.iov_base = (void *) &disabled,
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.iov_len = sizeof (disabled)
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};
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/* This is the standard reply in case we haven't found the dataset. */
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static const pw_response_header notfound =
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{
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.version = NSCD_VERSION,
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.found = 0,
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.pw_name_len = 0,
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.pw_passwd_len = 0,
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.pw_uid = -1,
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.pw_gid = -1,
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.pw_gecos_len = 0,
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.pw_dir_len = 0,
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.pw_shell_len = 0
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};
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static time_t
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cache_addpw (struct database_dyn *db, int fd, request_header *req,
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const void *key, struct passwd *pwd, uid_t owner,
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struct hashentry *const he, struct datahead *dh, int errval)
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{
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bool all_written = true;
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ssize_t total;
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time_t t = time (NULL);
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/* We allocate all data in one memory block: the iov vector,
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the response header and the dataset itself. */
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struct dataset
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{
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struct datahead head;
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pw_response_header resp;
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char strdata[0];
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} *dataset;
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assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
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time_t timeout = MAX_TIMEOUT_VALUE;
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if (pwd == NULL)
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{
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if (he != NULL && errval == EAGAIN)
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{
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/* If we have an old record available but cannot find one
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now because the service is not available we keep the old
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record and make sure it does not get removed. */
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if (reload_count != UINT_MAX && dh->nreloads == reload_count)
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/* Do not reset the value if we never not reload the record. */
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dh->nreloads = reload_count - 1;
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/* Reload with the same time-to-live value. */
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timeout = dh->timeout = t + db->postimeout;
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total = 0;
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}
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else
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{
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/* We have no data. This means we send the standard reply for this
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case. */
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total = sizeof (notfound);
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if (fd != -1
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&& TEMP_FAILURE_RETRY (send (fd, ¬found, total,
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MSG_NOSIGNAL)) != total)
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all_written = false;
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/* If we have a transient error or cannot permanently store
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the result, so be it. */
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if (errno == EAGAIN || __builtin_expect (db->negtimeout == 0, 0))
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{
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/* Mark the old entry as obsolete. */
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if (dh != NULL)
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dh->usable = false;
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}
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else if ((dataset = mempool_alloc (db, (sizeof (struct dataset)
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+ req->key_len), 1)) != NULL)
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{
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timeout = datahead_init_neg (&dataset->head,
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(sizeof (struct dataset)
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+ req->key_len), total,
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db->negtimeout);
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/* This is the reply. */
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memcpy (&dataset->resp, ¬found, total);
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/* Copy the key data. */
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char *key_copy = memcpy (dataset->strdata, key, req->key_len);
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/* If necessary, we also propagate the data to disk. */
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if (db->persistent)
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{
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// XXX async OK?
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uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
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msync ((void *) pval,
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((uintptr_t) dataset & pagesize_m1)
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+ sizeof (struct dataset) + req->key_len, MS_ASYNC);
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}
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(void) cache_add (req->type, key_copy, req->key_len,
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&dataset->head, true, db, owner, he == NULL);
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pthread_rwlock_unlock (&db->lock);
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/* Mark the old entry as obsolete. */
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if (dh != NULL)
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dh->usable = false;
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}
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}
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}
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else
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{
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/* Determine the I/O structure. */
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size_t pw_name_len = strlen (pwd->pw_name) + 1;
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size_t pw_passwd_len = strlen (pwd->pw_passwd) + 1;
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size_t pw_gecos_len = strlen (pwd->pw_gecos) + 1;
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size_t pw_dir_len = strlen (pwd->pw_dir) + 1;
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size_t pw_shell_len = strlen (pwd->pw_shell) + 1;
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char *cp;
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const size_t key_len = strlen (key);
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const size_t buf_len = 3 * sizeof (pwd->pw_uid) + key_len + 1;
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char *buf = alloca (buf_len);
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ssize_t n;
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/* We need this to insert the `byuid' entry. */
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int key_offset;
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n = snprintf (buf, buf_len, "%d%c%n%s", pwd->pw_uid, '\0',
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&key_offset, (char *) key) + 1;
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total = (offsetof (struct dataset, strdata)
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+ pw_name_len + pw_passwd_len
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+ pw_gecos_len + pw_dir_len + pw_shell_len);
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/* If we refill the cache, first assume the reconrd did not
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change. Allocate memory on the cache since it is likely
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discarded anyway. If it turns out to be necessary to have a
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new record we can still allocate real memory. */
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bool alloca_used = false;
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dataset = NULL;
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if (he == NULL)
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{
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/* Prevent an INVALIDATE request from pruning the data between
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the two calls to cache_add. */
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if (db->propagate)
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pthread_mutex_lock (&db->prune_run_lock);
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dataset = (struct dataset *) mempool_alloc (db, total + n, 1);
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}
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if (dataset == NULL)
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{
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if (he == NULL && db->propagate)
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pthread_mutex_unlock (&db->prune_run_lock);
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/* We cannot permanently add the result in the moment. But
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we can provide the result as is. Store the data in some
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temporary memory. */
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dataset = (struct dataset *) alloca (total + n);
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/* We cannot add this record to the permanent database. */
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alloca_used = true;
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}
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timeout = datahead_init_pos (&dataset->head, total + n,
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total - offsetof (struct dataset, resp),
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he == NULL ? 0 : dh->nreloads + 1,
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db->postimeout);
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dataset->resp.version = NSCD_VERSION;
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dataset->resp.found = 1;
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dataset->resp.pw_name_len = pw_name_len;
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dataset->resp.pw_passwd_len = pw_passwd_len;
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dataset->resp.pw_uid = pwd->pw_uid;
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dataset->resp.pw_gid = pwd->pw_gid;
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dataset->resp.pw_gecos_len = pw_gecos_len;
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dataset->resp.pw_dir_len = pw_dir_len;
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dataset->resp.pw_shell_len = pw_shell_len;
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cp = dataset->strdata;
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/* Copy the strings over into the buffer. */
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cp = mempcpy (cp, pwd->pw_name, pw_name_len);
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cp = mempcpy (cp, pwd->pw_passwd, pw_passwd_len);
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cp = mempcpy (cp, pwd->pw_gecos, pw_gecos_len);
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cp = mempcpy (cp, pwd->pw_dir, pw_dir_len);
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cp = mempcpy (cp, pwd->pw_shell, pw_shell_len);
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/* Finally the stringified UID value. */
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memcpy (cp, buf, n);
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char *key_copy = cp + key_offset;
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assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
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assert (cp == dataset->strdata + total - offsetof (struct dataset,
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strdata));
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/* Now we can determine whether on refill we have to create a new
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record or not. */
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if (he != NULL)
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{
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assert (fd == -1);
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if (dataset->head.allocsize == dh->allocsize
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&& dataset->head.recsize == dh->recsize
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&& memcmp (&dataset->resp, dh->data,
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dh->allocsize - offsetof (struct dataset, resp)) == 0)
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{
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/* The data has not changed. We will just bump the
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timeout value. Note that the new record has been
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allocated on the stack and need not be freed. */
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dh->timeout = dataset->head.timeout;
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++dh->nreloads;
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}
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else
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{
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/* We have to create a new record. Just allocate
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appropriate memory and copy it. */
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struct dataset *newp
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= (struct dataset *) mempool_alloc (db, total + n, 1);
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if (newp != NULL)
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{
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/* Adjust pointer into the memory block. */
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cp = (char *) newp + (cp - (char *) dataset);
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key_copy = (char *) newp + (key_copy - (char *) dataset);
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dataset = memcpy (newp, dataset, total + n);
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alloca_used = false;
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}
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/* Mark the old record as obsolete. */
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dh->usable = false;
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}
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}
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else
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{
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/* We write the dataset before inserting it to the database
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since while inserting this thread might block and so would
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unnecessarily let the receiver wait. */
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assert (fd != -1);
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if (writeall (fd, &dataset->resp, dataset->head.recsize)
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!= dataset->head.recsize)
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all_written = false;
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}
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/* Add the record to the database. But only if it has not been
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stored on the stack. */
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if (! alloca_used)
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{
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/* If necessary, we also propagate the data to disk. */
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if (db->persistent)
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{
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// XXX async OK?
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uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
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msync ((void *) pval,
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((uintptr_t) dataset & pagesize_m1) + total + n,
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MS_ASYNC);
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}
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/* NB: in the following code we always must add the entry
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marked with FIRST first. Otherwise we end up with
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dangling "pointers" in case a latter hash entry cannot be
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added. */
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bool first = true;
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/* If the request was by UID, add that entry first. */
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if (req->type == GETPWBYUID)
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{
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if (cache_add (GETPWBYUID, cp, key_offset, &dataset->head, true,
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db, owner, he == NULL) < 0)
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goto out;
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first = false;
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}
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/* If the key is different from the name add a separate entry. */
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else if (strcmp (key_copy, dataset->strdata) != 0)
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{
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if (cache_add (GETPWBYNAME, key_copy, key_len + 1,
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&dataset->head, true, db, owner, he == NULL) < 0)
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goto out;
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first = false;
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}
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/* We have to add the value for both, byname and byuid. */
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if ((req->type == GETPWBYNAME || db->propagate)
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&& __builtin_expect (cache_add (GETPWBYNAME, dataset->strdata,
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pw_name_len, &dataset->head,
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first, db, owner, he == NULL)
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== 0, 1))
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{
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if (req->type == GETPWBYNAME && db->propagate)
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(void) cache_add (GETPWBYUID, cp, key_offset, &dataset->head,
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false, db, owner, false);
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}
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out:
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pthread_rwlock_unlock (&db->lock);
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if (he == NULL && db->propagate)
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pthread_mutex_unlock (&db->prune_run_lock);
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}
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}
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if (__builtin_expect (!all_written, 0) && debug_level > 0)
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{
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char buf[256];
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dbg_log (_("short write in %s: %s"), __FUNCTION__,
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strerror_r (errno, buf, sizeof (buf)));
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}
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return timeout;
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}
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union keytype
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{
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void *v;
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uid_t u;
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};
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static int
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lookup (int type, union keytype key, struct passwd *resultbufp, char *buffer,
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size_t buflen, struct passwd **pwd)
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{
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if (type == GETPWBYNAME)
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return __getpwnam_r (key.v, resultbufp, buffer, buflen, pwd);
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else
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return __getpwuid_r (key.u, resultbufp, buffer, buflen, pwd);
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}
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static time_t
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addpwbyX (struct database_dyn *db, int fd, request_header *req,
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union keytype key, const char *keystr, uid_t c_uid,
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struct hashentry *he, struct datahead *dh)
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{
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/* Search for the entry matching the key. Please note that we don't
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look again in the table whether the dataset is now available. We
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simply insert it. It does not matter if it is in there twice. The
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pruning function only will look at the timestamp. */
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struct passwd resultbuf;
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struct passwd *pwd;
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int errval = 0;
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struct scratch_buffer tmpbuf;
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scratch_buffer_init (&tmpbuf);
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if (__glibc_unlikely (debug_level > 0))
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{
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if (he == NULL)
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dbg_log (_("Haven't found \"%s\" in user database cache!"), keystr);
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else
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dbg_log (_("Reloading \"%s\" in user database cache!"), keystr);
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}
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while (lookup (req->type, key, &resultbuf,
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tmpbuf.data, tmpbuf.length, &pwd) != 0
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&& (errval = errno) == ERANGE)
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if (!scratch_buffer_grow (&tmpbuf))
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{
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/* We ran out of memory. We cannot do anything but sending a
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negative response. In reality this should never
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happen. */
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pwd = NULL;
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/* We set the error to indicate this is (possibly) a temporary
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error and that it does not mean the entry is not available
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at all. */
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errval = EAGAIN;
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break;
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}
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/* Add the entry to the cache. */
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time_t timeout = cache_addpw (db, fd, req, keystr, pwd, c_uid, he, dh,
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errval);
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scratch_buffer_free (&tmpbuf);
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return timeout;
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}
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void
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addpwbyname (struct database_dyn *db, int fd, request_header *req,
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void *key, uid_t c_uid)
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{
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union keytype u = { .v = key };
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addpwbyX (db, fd, req, u, key, c_uid, NULL, NULL);
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}
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time_t
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readdpwbyname (struct database_dyn *db, struct hashentry *he,
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struct datahead *dh)
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{
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request_header req =
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{
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.type = GETPWBYNAME,
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.key_len = he->len
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};
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union keytype u = { .v = db->data + he->key };
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return addpwbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
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}
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void
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addpwbyuid (struct database_dyn *db, int fd, request_header *req,
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void *key, uid_t c_uid)
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{
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char *ep;
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uid_t uid = strtoul ((char *) key, &ep, 10);
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if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
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{
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if (debug_level > 0)
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dbg_log (_("Invalid numeric uid \"%s\"!"), (char *) key);
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errno = EINVAL;
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return;
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}
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union keytype u = { .u = uid };
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addpwbyX (db, fd, req, u, key, c_uid, NULL, NULL);
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}
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time_t
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readdpwbyuid (struct database_dyn *db, struct hashentry *he,
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struct datahead *dh)
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{
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char *ep;
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uid_t uid = strtoul (db->data + he->key, &ep, 10);
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/* Since the key has been added before it must be OK. */
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assert (*(db->data + he->key) != '\0' && *ep == '\0');
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request_header req =
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{
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.type = GETPWBYUID,
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.key_len = he->len
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};
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union keytype u = { .u = uid };
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return addpwbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
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}
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