1 files changed, 533 insertions, 0 deletions

diff --git a/lib/dpkg/dbmodify.c b/lib/dpkg/dbmodify.c
new file mode 100644
index 0000000..b95bb77
--- /dev/null
+++ b/lib/dpkg/dbmodify.c
@@ -0,0 +1,533 @@
+/*
+ * libdpkg - Debian packaging suite library routines
+ * dbmodify.c - routines for managing dpkg database updates
+ *
+ * Copyright © 1994,1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
+ * Copyright © 2001 Wichert Akkerman <wichert@debian.org>
+ * Copyright © 2006-2014 Guillem Jover <guillem@debian.org>
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <compat.h>
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
+#include <time.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <dpkg/i18n.h>
+#include <dpkg/c-ctype.h>
+#include <dpkg/dpkg.h>
+#include <dpkg/dpkg-db.h>
+#include <dpkg/file.h>
+#include <dpkg/dir.h>
+#include <dpkg/triglib.h>
+
+static bool db_initialized;
+
+static enum modstatdb_rw cstatus=-1, cflags=0;
+static char *lockfile;
+static char *frontendlockfile;
+static char *statusfile, *availablefile;
+static char *importanttmpfile=NULL;
+static FILE *importanttmp;
+static int nextupdate;
+static char *updatesdir;
+static int updateslength;
+static struct varbuf updatefn;
+static struct varbuf_state updatefn_state;
+static struct varbuf uvb;
+
+static int ulist_select(const struct dirent *de) {
+  const char *p;
+  int l;
+  for (p= de->d_name, l=0; *p; p++, l++)
+    if (!c_isdigit(*p))
+      return 0;
+  if (l > IMPORTANTMAXLEN)
+    ohshit(_("updates directory contains file '%.250s' whose name is too long "
+           "(length=%d, max=%d)"), de->d_name, l, IMPORTANTMAXLEN);
+  if (updateslength == -1) updateslength= l;
+  else if (l != updateslength)
+    ohshit(_("updates directory contains files with different length names "
+           "(both %d and %d)"), l, updateslength);
+  return 1;
+}
+
+static void cleanupdates(void) {
+  struct dirent **cdlist;
+  int cdn, i;
+
+  parsedb(statusfile, pdb_parse_status, NULL);
+
+  updateslength= -1;
+  cdn = scandir(updatesdir, &cdlist, &ulist_select, alphasort);
+  if (cdn == -1) {
+    if (errno == ENOENT) {
+      if (cstatus >= msdbrw_write &&
+          dir_make_path(updatesdir, 0755) < 0)
+        ohshite(_("cannot create the dpkg updates directory %s"),
+                updatesdir);
+      return;
+    }
+    ohshite(_("cannot scan updates directory '%.255s'"), updatesdir);
+  }
+
+  if (cdn) {
+    for (i=0; i<cdn; i++) {
+      varbuf_rollback(&updatefn_state);
+      varbuf_add_str(&updatefn, cdlist[i]->d_name);
+      varbuf_end_str(&updatefn);
+      parsedb(updatefn.buf, pdb_parse_update, NULL);
+    }
+
+    if (cstatus >= msdbrw_write) {
+      writedb(statusfile, wdb_must_sync);
+
+      for (i=0; i<cdn; i++) {
+        varbuf_rollback(&updatefn_state);
+        varbuf_add_str(&updatefn, cdlist[i]->d_name);
+        varbuf_end_str(&updatefn);
+        if (unlink(updatefn.buf))
+          ohshite(_("failed to remove incorporated update file %.255s"),
+                  updatefn.buf);
+      }
+
+      dir_sync_path(updatesdir);
+    }
+
+    for (i = 0; i < cdn; i++)
+      free(cdlist[i]);
+  }
+  free(cdlist);
+
+  nextupdate= 0;
+}
+
+static void createimptmp(void) {
+  int i;
+
+  onerr_abort++;
+
+  importanttmp= fopen(importanttmpfile,"w");
+  if (!importanttmp)
+    ohshite(_("unable to create '%.255s'"), importanttmpfile);
+  setcloexec(fileno(importanttmp),importanttmpfile);
+  for (i=0; i<512; i++) fputs("#padding\n",importanttmp);
+  if (ferror(importanttmp))
+    ohshite(_("unable to fill %.250s with padding"),importanttmpfile);
+  if (fflush(importanttmp))
+    ohshite(_("unable to flush %.250s after padding"), importanttmpfile);
+  if (fseek(importanttmp,0,SEEK_SET))
+    ohshite(_("unable to seek to start of %.250s after padding"),
+	    importanttmpfile);
+
+  onerr_abort--;
+}
+
+static const struct fni {
+  const char *suffix;
+  char **store;
+} fnis[] = {
+  {
+    .suffix = LOCKFILE,
+    .store = &lockfile,
+  }, {
+    .suffix = FRONTENDLOCKFILE,
+    .store = &frontendlockfile,
+  }, {
+    .suffix = STATUSFILE,
+    .store = &statusfile,
+  }, {
+    .suffix = AVAILFILE,
+    .store = &availablefile,
+  }, {
+    .suffix = UPDATESDIR,
+    .store = &updatesdir,
+  }, {
+    .suffix = UPDATESDIR "/" IMPORTANTTMP,
+    .store = &importanttmpfile,
+  }, {
+    .suffix = NULL,
+    .store = NULL,
+  }
+};
+
+void
+modstatdb_init(void)
+{
+  const struct fni *fnip;
+
+  if (db_initialized)
+    return;
+
+  for (fnip = fnis; fnip->suffix; fnip++) {
+    free(*fnip->store);
+    *fnip->store = dpkg_db_get_path(fnip->suffix);
+  }
+
+  varbuf_init(&updatefn, strlen(updatesdir) + 1 + IMPORTANTMAXLEN);
+  varbuf_add_dir(&updatefn, updatesdir);
+  varbuf_end_str(&updatefn);
+  varbuf_snapshot(&updatefn, &updatefn_state);
+
+  db_initialized = true;
+}
+
+void
+modstatdb_done(void)
+{
+  const struct fni *fnip;
+
+  if (!db_initialized)
+    return;
+
+  for (fnip = fnis; fnip->suffix; fnip++) {
+    free(*fnip->store);
+    *fnip->store = NULL;
+  }
+  varbuf_destroy(&updatefn);
+
+  db_initialized = false;
+}
+
+static int dblockfd = -1;
+static int frontendlockfd = -1;
+
+bool
+modstatdb_is_locked(void)
+{
+  int lockfd;
+  bool locked;
+
+  if (dblockfd == -1) {
+    lockfd = open(lockfile, O_RDONLY);
+    if (lockfd == -1) {
+      if (errno == ENOENT)
+        return false;
+      ohshite(_("unable to check lock file for dpkg database directory %s"),
+              dpkg_db_get_dir());
+    }
+  } else {
+    lockfd = dblockfd;
+  }
+
+  locked = file_is_locked(lockfd, lockfile);
+
+  /* We only close the file if there was no lock open, otherwise we would
+   * release the existing lock on close. */
+  if (dblockfd == -1)
+    close(lockfd);
+
+  return locked;
+}
+
+bool
+modstatdb_can_lock(void)
+{
+  if (dblockfd >= 0)
+    return true;
+
+  if (getenv("DPKG_FRONTEND_LOCKED") == NULL) {
+    frontendlockfd = open(frontendlockfile, O_RDWR | O_CREAT | O_TRUNC, 0660);
+    if (frontendlockfd == -1) {
+      if (errno == EACCES || errno == EPERM)
+        return false;
+      else
+        ohshite(_("unable to open/create dpkg frontend lock for directory %s"),
+                dpkg_db_get_dir());
+    }
+  } else {
+    frontendlockfd = -1;
+  }
+
+  dblockfd = open(lockfile, O_RDWR | O_CREAT | O_TRUNC, 0660);
+  if (dblockfd == -1) {
+    if (errno == EACCES || errno == EPERM)
+      return false;
+    else
+      ohshite(_("unable to open/create dpkg database lock file for directory %s"),
+              dpkg_db_get_dir());
+  }
+
+  return true;
+}
+
+void
+modstatdb_lock(void)
+{
+  if (!modstatdb_can_lock())
+    ohshit(_("you do not have permission to lock the dpkg database directory %s"),
+           dpkg_db_get_dir());
+
+  if (frontendlockfd != -1)
+    file_lock(&frontendlockfd, FILE_LOCK_NOWAIT, frontendlockfile,
+              _("dpkg frontend lock"));
+  file_lock(&dblockfd, FILE_LOCK_NOWAIT, lockfile,
+            _("dpkg database lock"));
+}
+
+void
+modstatdb_unlock(void)
+{
+  /* Unlock. */
+  pop_cleanup(ehflag_normaltidy);
+  if (frontendlockfd != -1)
+    pop_cleanup(ehflag_normaltidy);
+
+  dblockfd = -1;
+  frontendlockfd = -1;
+}
+
+enum modstatdb_rw
+modstatdb_open(enum modstatdb_rw readwritereq)
+{
+  bool db_can_access = false;
+
+  modstatdb_init();
+
+  cflags = readwritereq & msdbrw_available_mask;
+  readwritereq &= ~msdbrw_available_mask;
+
+  switch (readwritereq) {
+  case msdbrw_needsuperuser:
+  case msdbrw_needsuperuserlockonly:
+    if (getuid() || geteuid())
+      ohshit(_("requested operation requires superuser privilege"));
+    /* Fall through. */
+  case msdbrw_write: case msdbrw_writeifposs:
+    db_can_access = access(dpkg_db_get_dir(), W_OK) == 0;
+    if (!db_can_access && errno == ENOENT) {
+      if (dir_make_path(dpkg_db_get_dir(), 0755) == 0)
+        db_can_access = true;
+      else if (readwritereq >= msdbrw_write)
+        ohshite(_("cannot create the dpkg database directory %s"),
+                dpkg_db_get_dir());
+      else if (errno == EROFS)
+        /* If we cannot create the directory on read-only modes on read-only
+         * filesystems, make it look like an access error to be skipped. */
+        errno = EACCES;
+    }
+
+    if (!db_can_access) {
+      if (errno != EACCES)
+        ohshite(_("unable to access the dpkg database directory %s"),
+                dpkg_db_get_dir());
+      else if (readwritereq >= msdbrw_write)
+        ohshit(_("required read/write access to the dpkg database directory %s"),
+               dpkg_db_get_dir());
+      cstatus= msdbrw_readonly;
+    } else {
+      modstatdb_lock();
+      cstatus= (readwritereq == msdbrw_needsuperuserlockonly ?
+                msdbrw_needsuperuserlockonly :
+                msdbrw_write);
+    }
+    break;
+  case msdbrw_readonly:
+    cstatus= msdbrw_readonly; break;
+  default:
+    internerr("unknown modstatdb_rw '%d'", readwritereq);
+  }
+
+  dpkg_arch_load_list();
+
+  if (cstatus != msdbrw_needsuperuserlockonly) {
+    cleanupdates();
+    if (cflags >= msdbrw_available_readonly)
+      parsedb(availablefile, pdb_parse_available, NULL);
+  }
+
+  if (cstatus >= msdbrw_write) {
+    createimptmp();
+    varbuf_init(&uvb, 10240);
+  }
+
+  trig_fixup_awaiters(cstatus);
+  trig_incorporate(cstatus);
+
+  return cstatus;
+}
+
+enum modstatdb_rw
+modstatdb_get_status(void)
+{
+  return cstatus;
+}
+
+void modstatdb_checkpoint(void) {
+  int i;
+
+  if (cstatus < msdbrw_write)
+    internerr("modstatdb status '%d' is not writable", cstatus);
+
+  writedb(statusfile, wdb_must_sync);
+
+  for (i=0; i<nextupdate; i++) {
+    varbuf_rollback(&updatefn_state);
+    varbuf_printf(&updatefn, IMPORTANTFMT, i);
+
+    /* Have we made a real mess? */
+    if (varbuf_rollback_len(&updatefn_state) > IMPORTANTMAXLEN)
+      internerr("modstatdb update entry name '%s' longer than %d",
+                varbuf_rollback_start(&updatefn_state), IMPORTANTMAXLEN);
+
+    if (unlink(updatefn.buf))
+      ohshite(_("failed to remove my own update file %.255s"), updatefn.buf);
+  }
+
+  dir_sync_path(updatesdir);
+
+  nextupdate= 0;
+}
+
+void modstatdb_shutdown(void) {
+  if (cflags >= msdbrw_available_write)
+    writedb(availablefile, wdb_dump_available);
+
+  switch (cstatus) {
+  case msdbrw_write:
+    modstatdb_checkpoint();
+    /* Tidy up a bit, but don't worry too much about failure. */
+    fclose(importanttmp);
+    (void)unlink(importanttmpfile);
+    varbuf_destroy(&uvb);
+    /* Fall through. */
+  case msdbrw_needsuperuserlockonly:
+    modstatdb_unlock();
+  default:
+    break;
+  }
+
+  pkg_hash_reset();
+
+  modstatdb_done();
+}
+
+static void
+modstatdb_note_core(struct pkginfo *pkg)
+{
+  if (cstatus < msdbrw_write)
+    internerr("modstatdb status '%d' is not writable", cstatus);
+
+  varbuf_reset(&uvb);
+  varbuf_stanza(&uvb, pkg, &pkg->installed);
+
+  if (fwrite(uvb.buf, 1, uvb.used, importanttmp) != uvb.used)
+    ohshite(_("unable to write updated status of '%.250s'"),
+            pkg_name(pkg, pnaw_nonambig));
+  if (fflush(importanttmp))
+    ohshite(_("unable to flush updated status of '%.250s'"),
+            pkg_name(pkg, pnaw_nonambig));
+  if (ftruncate(fileno(importanttmp), uvb.used))
+    ohshite(_("unable to truncate for updated status of '%.250s'"),
+            pkg_name(pkg, pnaw_nonambig));
+  if (fsync(fileno(importanttmp)))
+    ohshite(_("unable to fsync updated status of '%.250s'"),
+            pkg_name(pkg, pnaw_nonambig));
+  if (fclose(importanttmp))
+    ohshite(_("unable to close updated status of '%.250s'"),
+            pkg_name(pkg, pnaw_nonambig));
+  varbuf_rollback(&updatefn_state);
+  varbuf_printf(&updatefn, IMPORTANTFMT, nextupdate);
+  if (rename(importanttmpfile, updatefn.buf))
+    ohshite(_("unable to install updated status of '%.250s'"),
+            pkg_name(pkg, pnaw_nonambig));
+
+  dir_sync_path(updatesdir);
+
+  /* Have we made a real mess? */
+  if (varbuf_rollback_len(&updatefn_state) > IMPORTANTMAXLEN)
+    internerr("modstatdb update entry name '%s' longer than %d",
+              varbuf_rollback_start(&updatefn_state), IMPORTANTMAXLEN);
+
+  nextupdate++;
+
+  if (nextupdate > MAXUPDATES) {
+    modstatdb_checkpoint();
+    nextupdate = 0;
+  }
+
+  createimptmp();
+}
+
+/*
+ * Note: If anyone wants to set some triggers-pending, they must also
+ * set status appropriately, or we will undo it. That is, it is legal
+ * to call this when pkg->status and pkg->trigpend_head disagree and
+ * in that case pkg->status takes precedence and pkg->trigpend_head
+ * will be adjusted.
+ */
+void modstatdb_note(struct pkginfo *pkg) {
+  struct trigaw *ta;
+
+  onerr_abort++;
+
+  /* Clear pending triggers here so that only code that sets the status
+   * to interesting (for triggers) values has to care about triggers. */
+  if (pkg->status != PKG_STAT_TRIGGERSPENDING &&
+      pkg->status != PKG_STAT_TRIGGERSAWAITED)
+    pkg->trigpend_head = NULL;
+
+  if (pkg->status <= PKG_STAT_CONFIGFILES) {
+    for (ta = pkg->trigaw.head; ta; ta = ta->sameaw.next)
+      ta->aw = NULL;
+    pkg->trigaw.head = pkg->trigaw.tail = NULL;
+  }
+
+  if (pkg->status_dirty) {
+    log_message("status %s %s %s", pkg_status_name(pkg),
+                pkg_name(pkg, pnaw_always),
+                versiondescribe_c(&pkg->installed.version, vdew_nonambig));
+    statusfd_send("status: %s: %s", pkg_name(pkg, pnaw_nonambig),
+                  pkg_status_name(pkg));
+
+    pkg->status_dirty = false;
+  }
+
+  if (cstatus >= msdbrw_write)
+    modstatdb_note_core(pkg);
+
+  if (!pkg->trigpend_head && pkg->othertrigaw_head) {
+    /* Automatically remove us from other packages' Triggers-Awaited.
+     * We do this last because we want to maximize our chances of
+     * successfully recording the status of the package we were
+     * pointed at by our caller, although there is some risk of
+     * leaving us in a slightly odd situation which is cleared up
+     * by the trigger handling logic in deppossi_ok_found. */
+    trig_clear_awaiters(pkg);
+  }
+
+  onerr_abort--;
+}
+
+void
+modstatdb_note_ifwrite(struct pkginfo *pkg)
+{
+  if (cstatus >= msdbrw_write)
+    modstatdb_note(pkg);
+}
+