+++ /dev/null
-/* -*-c-*-
- *
- * $Id$
- *
- * System-dependent key filing operations
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <sys/types.h>
-#include <sys/time.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <fcntl.h>
-
-#include <mLib/dstr.h>
-#include <mLib/lock.h>
-
-#include "key.h"
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @fdcopy@ --- *
- *
- * Arguments: @int source@ = source file descriptor
- * @int dest@ = destination file descriptor
- *
- * Returns: Zero if OK, nonzero otherwise.
- *
- * Use: Copies data from one file descriptor to another.
- */
-
-static int fdcopy(int source, int dest)
-{
- char buf[4096];
- char *p;
-
- if (lseek(source, 0, SEEK_SET) < 0||
- lseek(dest, 0, SEEK_SET) < 0 ||
- ftruncate(dest, 0) < 0)
- return (-1);
- for (;;) {
- int n = read(source, buf, sizeof(buf));
- if (n < 0)
- return (-1);
- else if (n == 0)
- break;
- p = buf;
- while (n) {
- int nn = write(dest, p, n);
- if (nn < 0)
- return (-1);
- p += nn;
- n -= nn;
- }
- }
- return (0);
-}
-
-/* --- @key_save@ --- *
- *
- * Arguments: @key_file *f@ = pointer to key file block
- *
- * Returns: A @KWRITE_@ code indicating how well it worked.
- *
- * Use: Writes a key file's data back to the actual file. This code
- * is extremely careful about error handling. It should usually
- * be able to back out somewhere sensible, but it can tell when
- * it's got itself into a real pickle and starts leaving well
- * alone.
- *
- * Callers, please make sure that you ring alarm bells when this
- * function returns @KWRITE_BROKEN@.
- */
-
-int key_save(key_file *f)
-{
- dstr n_older = DSTR_INIT, n_old = DSTR_INIT, n_new = DSTR_INIT;
- int rc = KWRITE_FAIL;
-
- if (!(f->f & KF_MODIFIED))
- return (KWRITE_OK);
- if (!f->fp)
- return (KWRITE_FAIL);
-
- /* --- Write a new key file out --- *
- *
- * Check for an error after each key line. This ought to be enough.
- * Checking after each individual byte write and @fprintf@ isn't much fun.
- */
-
- dstr_putf(&n_new, "%s.new", f->name);
-
- {
- key *k;
- key_iter i;
- FILE *fp;
-
- if ((fp = fopen(n_new.buf, "w")) == 0)
- goto fail_open;
-
- for (key_mkiter(&i, f); (k = key_next(&i)) != 0; ) {
- if (key_extract(f, k, fp, 0)) {
- fclose(fp);
- goto fail_write;
- }
- }
-
- if (fclose(fp))
- goto fail_write;
- }
-
- /* --- Set up the other filenames --- */
-
- dstr_putf(&n_older, "%s.older", f->name);
- dstr_putf(&n_old, "%s.old", f->name);
-
- /* --- Move the current backup on one --- *
- *
- * If the `older' file exists, then we're in need of attention.
- */
-
- {
- struct stat st;
- if (stat(n_older.buf, &st) == 0 || errno != ENOENT) {
- errno = EEXIST;
- rc = KWRITE_BROKEN;
- goto fail_shift;
- }
- if (rename(n_old.buf, n_older.buf) && errno != ENOENT)
- goto fail_shift;
- }
-
- /* --- Copy the current file to the backup --- */
-
- {
- int fd;
- if ((fd = open(n_old.buf, O_WRONLY | O_CREAT | O_EXCL, 0600)) < 0)
- goto fail_backup;
- if (fdcopy(fileno(f->fp), fd)) {
- close(fd);
- goto fail_backup;
- }
- if (close(fd))
- goto fail_backup;
- }
-
- /* --- Copy the newly created file to the current one --- *
- *
- * This is the dangerous bit.
- */
-
- {
- int fd;
- if ((fd = open(n_new.buf, O_RDONLY)) < 0)
- goto fail_update;
- if (fdcopy(fd, fileno(f->fp))) {
- close(fd);
- goto fail_update;
- }
- close(fd);
- if (fsync(fileno(f->fp)))
- goto fail_update;
- }
-
- /* --- Clean up --- *
- *
- * Remove the `new' file and the `older' backup. Then we're done.
- */
-
- unlink(n_new.buf);
- unlink(n_older.buf);
- dstr_destroy(&n_new);
- dstr_destroy(&n_old);
- dstr_destroy(&n_older);
- return (KWRITE_OK);
-
- /* --- Failure while writing the new key file --- *
- *
- * I need to copy the backup back. If that fails then I'm really stuffed.
- * If not, then I might as well try to get the backups sorted back out
- * again.
- */
-
-fail_update:
- {
- int fd;
- int e = errno;
-
- if ((fd = open(n_old.buf, O_RDONLY)) < 0)
- rc = KWRITE_BROKEN;
- else if (fdcopy(fd, fileno(f->fp))) {
- close(fd);
- rc = KWRITE_BROKEN;
- } else {
- close(fd);
- if (fsync(fileno(f->fp)))
- rc = KWRITE_BROKEN;
- }
-
- errno = e;
- if (rc == KWRITE_BROKEN)
- goto fail_shift;
- }
- /* Now drop through */
-
- /* --- Failure while writing the new backup --- *
- *
- * The new backup isn't any use. Try to recover the old one.
- */
-
-fail_backup:
- {
- int e = errno;
- unlink(n_old.buf);
- if (rename(n_older.buf, n_old.buf) && errno != ENOENT)
- rc = KWRITE_BROKEN;
- errno = e;
- }
- /* Now drop through */
-
- /* --- Failure while demoting the current backup --- *
- *
- * Leave the completed output file there for the operator in case he wants
- * to clean up.
- */
-
-fail_shift:
- dstr_destroy(&n_new);
- dstr_destroy(&n_old);
- dstr_destroy(&n_older);
- return (rc);
-
- /* --- Failure during write of new data --- *
- *
- * Clean up the new file and return. These errors can never cause
- * breakage.
- */
-
-fail_write:
- unlink(n_new.buf);
-fail_open:
- dstr_destroy(&n_new);
- return (rc);
-}
-
-/* --- @key_lockfile@ --- *
- *
- * Arguments: @key_file *f@ = pointer to file structure to initialize
- * @const char *file@ = pointer to the file name
- * @unsigned how@ = opening options (@KOPEN_*@).
- *
- * Returns: Zero if it worked, nonzero otherwise.
- *
- * Use: Opens a keyfile and stores the information needed for
- * continued access in the structure.
- *
- * If the file is opened with @KOPEN_WRITE@, it's created if
- * necessary with read and write permissions for owner only, and
- * locked for update while it's open.
- *
- * This is a system-dependent routine, and only really intended
- * for the private use of @key_open@.
- */
-
-int key_lockfile(key_file *f, const char *file, unsigned how)
-{
- int of, lf;
- const char *ff;
- int fd;
-
- /* --- Handle the magic no-file option --- */
-
- if (how & KOPEN_NOFILE) {
- f->fp = 0;
- return (0);
- }
-
- /* --- Lots of things depend on whether we're writing --- */
-
- switch (how & KOPEN_MASK) {
- case KOPEN_READ:
- of = O_RDONLY;
- lf = LOCK_NONEXCL;
- ff = "r";
- break;
- case KOPEN_WRITE:
- of = O_RDWR | O_CREAT;
- lf = LOCK_EXCL;
- ff = "r+";
- break;
- default:
- errno = EINVAL;
- return (-1);
- }
-
- /* --- Open and lock the file --- */
-
- if ((fd = open(file, of, 0600)) < 0)
- return (-1);
- if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0 ||
- lock_file(fd, lf) < 0 ||
- (f->fp = fdopen(fd, ff)) == 0) {
- close(fd);
- return (-1);
- }
-
- return (0);
-}
-
-/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff