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-rw-r--r--src/check_mandirs.c1018
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diff --git a/src/check_mandirs.c b/src/check_mandirs.c
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+++ b/src/check_mandirs.c
@@ -0,0 +1,1018 @@
+/*
+ * check_mandirs.c: used to auto-update the database caches
+ *
+ * Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
+ * Copyright (C) 2001, 2002, 2003, 2004, 2007, 2008, 2009, 2010, 2011
+ * Colin Watson.
+ *
+ * This file is part of man-db.
+ *
+ * man-db 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.
+ *
+ * man-db 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 man-db; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Mon May 2 17:36:33 BST 1994 Wilf. (G.Wilford@ee.surrey.ac.uk)
+ *
+ * CJW: Many changes to whatis parsing. Added database purging.
+ * See ChangeLog for details.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <errno.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <unistd.h>
+
+#include "attribute.h"
+#include "dirname.h"
+#include "error.h"
+#include "gl_array_list.h"
+#include "gl_hash_map.h"
+#include "gl_xlist.h"
+#include "gl_xmap.h"
+#include "stat-time.h"
+#include "timespec.h"
+#include "xalloc.h"
+#include "xvasprintf.h"
+
+#include "gettext.h"
+#define _(String) gettext (String)
+
+#include "manconfig.h"
+
+#include "appendstr.h"
+#include "compression.h"
+#include "debug.h"
+#include "fatal.h"
+#include "filenames.h"
+#include "glcontainers.h"
+#include "orderfiles.h"
+#include "security.h"
+#include "util.h"
+
+#include "mydbm.h"
+#include "db_storage.h"
+
+#include "descriptions.h"
+#include "globbing.h"
+#include "lexgrog.h"
+#include "manp.h"
+#include "ult_src.h"
+#include "check_mandirs.h"
+
+bool opt_test; /* don't update db */
+int pages;
+bool force_rescan = false;
+
+gl_map_t whatis_map = NULL;
+
+struct whatis {
+ char *whatis;
+ char *filters;
+};
+
+static void whatis_free (const void *value)
+{
+ struct whatis *whatis = (struct whatis *) value;
+
+ free (whatis->whatis);
+ free (whatis->filters);
+ free (whatis);
+}
+
+static void gripe_multi_extensions (const char *path, const char *sec,
+ const char *name, const char *ext)
+{
+ if (quiet < 2)
+ error (0, 0,
+ _("warning: %s/man%s/%s.%s*: competing extensions"),
+ path, sec, name, ext);
+}
+
+/* Test whether an errno value is EAGAIN or (on systems where it differs)
+ * EWOULDBLOCK. This is a separate function mainly in order to be able to
+ * control GCC diagnostics in one place.
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wlogical-op"
+static inline bool is_eagain (int err)
+{
+ return err == EAGAIN || err == EWOULDBLOCK;
+}
+#pragma GCC diagnostic pop
+
+static void gripe_rwopen_failed (MYDBM_FILE dbf)
+{
+ if (errno == EACCES || errno == EROFS)
+ debug ("database %s is read-only\n", dbf->name);
+ else if (is_eagain (errno))
+ debug ("database %s is locked by another process\n", dbf->name);
+ else {
+#ifdef MAN_DB_UPDATES
+ if (!quiet)
+#endif /* MAN_DB_UPDATES */
+ error (0, errno, _("can't update index cache %s"),
+ dbf->name);
+ }
+}
+
+static bool ensure_db_open (MYDBM_FILE dbf)
+{
+ if (dbf->file)
+ return true;
+ if (!MYDBM_RWOPEN (dbf))
+ return false;
+ return true;
+}
+
+/* Take absolute filename and path (for ult_src) and do sanity checks on
+ * file. Also check that file is non-zero in length and is not already in
+ * the db. If not, find its ult_src() and see if we have the whatis cached,
+ * otherwise cache it in case we trace another manpage back to it. Next,
+ * store it in the db along with any references found in the whatis.
+ */
+void test_manfile (MYDBM_FILE dbf, const char *file, const char *path)
+{
+ char *manpage_base;
+ const struct ult_value *ult;
+ struct lexgrog lg;
+ struct mandata *info, *exists;
+ struct compression *comp;
+ struct stat buf;
+ size_t len;
+ const struct whatis *whatis;
+
+ debug ("\ntest_manfile: considering %s\n", file);
+
+ memset (&lg, 0, sizeof (struct lexgrog));
+
+ info = filename_info (file, quiet < 2);
+ if (!info)
+ return;
+ manpage_base = info->name; /* steal memory */
+ info->name = NULL;
+
+ comp = comp_info (file, true);
+ if (comp) {
+ len = strlen (comp->stem);
+ free (comp->stem);
+ } else
+ len = strlen (file);
+
+ /* to get mtime info */
+ (void) lstat (file, &buf);
+ info->mtime = get_stat_mtime (&buf);
+
+ /* check that our file actually contains some data */
+ if (buf.st_size == 0) {
+ /* man-db pre 2.3 place holder ? */
+ free_mandata_struct (info);
+ return;
+ }
+
+ /* Check for multiple pages whose details match except for having
+ * different compression extensions.
+ */
+ exists = dblookup_exact (dbf, manpage_base, info->ext, true);
+ if (exists && !STREQ (exists->comp, info->comp ? info->comp : "-")) {
+ char *abs_filename;
+
+ /* If the cached file still exists, then we have a collision:
+ * two pages that only differ by compression extension.
+ */
+ abs_filename = make_filename (path, NULL, exists, "man");
+ if (!abs_filename) {
+ if (!opt_test)
+ dbdelete (dbf, manpage_base, exists);
+ } else {
+ gripe_multi_extensions (path, exists->sec,
+ manpage_base, exists->ext);
+ free (abs_filename);
+ free_mandata_struct (exists);
+ free_mandata_struct (info);
+ return;
+ }
+ }
+ free_mandata_struct (exists);
+
+ /* Trace the file to its ultimate source, otherwise we'll be
+ * looking for whatis info in files containing only '.so
+ * manx/foo.x', which will give us an unobtainable whatis
+ * for the entry. */
+ ult = ult_src (file, path, &buf, SO_LINK | SOFT_LINK | HARD_LINK);
+
+ if (!ult) {
+ if (quiet < 2)
+ error (0, 0,
+ _("warning: %s: bad symlink or ROFF `.so' request"),
+ file);
+ free_mandata_struct (info);
+ return;
+ }
+
+ pages++; /* pages seen so far */
+
+ if (strncmp (ult->path, file, len) == 0)
+ info->id = ULT_MAN; /* ultimate source file */
+ else
+ info->id = SO_MAN; /* .so, sym or hard linked file */
+
+ /* Ok, here goes: Use a hash tree to store the ult_srcs with
+ * their whatis. Anytime after, check the hash tree, if it's there,
+ * use it. This saves us a find_name() which is a real hog.
+ *
+ * Use the full path in ult->path as the hash key so we don't have
+ * to clear the hash between calls.
+ */
+
+ if (!whatis_map)
+ whatis_map = new_string_map (GL_HASH_MAP, whatis_free);
+
+ whatis = gl_map_get (whatis_map, ult->path);
+ if (whatis) {
+ lg.whatis = whatis->whatis ? xstrdup (whatis->whatis) : NULL;
+ lg.filters =
+ whatis->filters ? xstrdup (whatis->filters) : NULL;
+ } else {
+ /* Cache miss; go and get the whatis info in its raw state. */
+ char *file_base = base_name (file);
+ struct whatis *new_whatis;
+
+ if (!STRNEQ (ult->path, file, len))
+ debug ("test_manfile: link not in cache:\n"
+ " source = %s\n"
+ " target = %s\n", file, ult->path);
+
+ lg.type = MANPAGE;
+ drop_effective_privs ();
+ find_name (ult->path, file_base, &lg, NULL);
+ free (file_base);
+ regain_effective_privs ();
+
+ new_whatis = XMALLOC (struct whatis);
+ new_whatis->whatis = lg.whatis ? xstrdup (lg.whatis) : NULL;
+ new_whatis->filters = lg.filters ? xstrdup (lg.filters) : NULL;
+ gl_map_put (whatis_map, xstrdup (ult->path), new_whatis);
+ }
+
+ debug ("\"%s\"\n", lg.whatis);
+
+ /* split up the raw whatis data and store references */
+ info->pointer = NULL; /* direct page, so far */
+ info->filter = lg.filters;
+ if (lg.whatis) {
+ gl_list_t descs = parse_descriptions (manpage_base, lg.whatis);
+ if (!opt_test)
+ store_descriptions (dbf, descs, info, path,
+ manpage_base, ult->trace);
+ gl_list_free (descs);
+ } else if (quiet < 2) {
+ (void) stat (ult->path, &buf);
+ if (buf.st_size == 0)
+ error (0, 0, _("warning: %s: ignoring empty file"),
+ ult->path);
+ else
+ error (0, 0,
+ _("warning: %s: whatis parse for %s(%s) failed"),
+ ult->path, manpage_base, info->ext);
+ }
+
+ free_mandata_struct (info);
+ free (lg.whatis);
+}
+
+static void add_dir_entries (MYDBM_FILE dbf, const char *path, char *infile)
+{
+ char *manpage;
+ int len;
+ struct dirent *newdir;
+ DIR *dir;
+ gl_list_t names;
+ const char *name;
+
+ manpage = xasprintf ("%s/%s/", path, infile);
+ assert (manpage);
+ len = strlen (manpage);
+
+ /*
+ * All filename entries in this dir should either be valid manpages
+ * or . files (such as current, parent dir).
+ */
+
+ dir = opendir (infile);
+ if (!dir) {
+ error (0, errno, _("can't search directory %s"), manpage);
+ free (manpage);
+ return;
+ }
+
+ names = new_string_list (GL_ARRAY_LIST, false);
+
+ /* strlen(newdir->d_name) could be replaced by newdir->d_reclen */
+
+ while ((newdir = readdir (dir)) != NULL) {
+ if (*newdir->d_name == '.' &&
+ strlen (newdir->d_name) < (size_t) 3)
+ continue;
+ gl_list_add_last (names, xstrdup (newdir->d_name));
+ }
+ closedir (dir);
+
+ order_files (infile, &names);
+
+ GL_LIST_FOREACH (names, name) {
+ manpage = appendstr (manpage, name, (void *) 0);
+ test_manfile (dbf, manpage, path);
+ *(manpage + len) = '\0';
+ }
+
+ gl_list_free (names);
+ free (manpage);
+}
+
+#ifdef MAN_OWNER
+extern uid_t uid; /* current effective user id */
+extern gid_t gid; /* current effective group id */
+
+/* Fix a path's ownership if possible and necessary. */
+void chown_if_possible (const char *path)
+{
+ struct stat st;
+ struct passwd *man_owner = get_man_owner ();
+
+ if (lstat (path, &st) != 0)
+ return;
+
+ if ((uid == 0 ||
+ (uid == man_owner->pw_uid && st.st_uid == man_owner->pw_uid &&
+ gid == man_owner->pw_gid)) &&
+ (st.st_uid != man_owner->pw_uid ||
+ st.st_gid != man_owner->pw_gid)) {
+ debug ("fixing ownership of %s\n", path);
+ if (lchown (path, man_owner->pw_uid, man_owner->pw_gid) < 0)
+ fatal (0, _("can't chown %s"), path);
+ }
+}
+#else /* !MAN_OWNER */
+void chown_if_possible (const char *path MAYBE_UNUSED)
+{
+}
+#endif /* MAN_OWNER */
+
+/* create the catman hierarchy if it doesn't exist */
+static void mkcatdirs (const char *mandir, const char *catdir)
+{
+ char *manname, *catname;
+
+ if (catdir) {
+ int oldmask = umask (022);
+ /* first the base catdir */
+ if (is_directory (catdir) != 1) {
+ regain_effective_privs ();
+ if (mkdir (catdir, 0755) < 0) {
+ if (!quiet)
+ error (0, 0,
+ _("warning: cannot create catdir %s"),
+ catdir);
+ debug ("warning: cannot create catdir %s\n",
+ catdir);
+ } else
+ debug ("created base catdir %s\n", catdir);
+ chown_if_possible (catdir);
+ drop_effective_privs ();
+ }
+ /* then the hierarchy */
+ catname = xasprintf ("%s/cat1", catdir);
+ manname = xasprintf ("%s/man1", mandir);
+ if (is_directory (catdir) == 1) {
+ int j;
+ regain_effective_privs ();
+ debug ("creating catdir hierarchy %s ", catdir);
+ for (j = 1; j <= 9; j++) {
+ catname[strlen (catname) - 1] = '0' + j;
+ manname[strlen (manname) - 1] = '0' + j;
+ if ((is_directory (manname) == 1)
+ && (is_directory (catname) != 1)) {
+ if (mkdir (catname, 0755) < 0) {
+ if (!quiet)
+ error (0, 0, _("warning: cannot create catdir %s"), catname);
+ debug ("warning: cannot create catdir %s\n", catname);
+ } else
+ debug (" cat%d", j);
+ chown_if_possible (catname);
+ }
+ }
+ debug ("\n");
+ drop_effective_privs ();
+ }
+ free (catname);
+ free (manname);
+ umask (oldmask);
+ }
+}
+
+/* We used to install cat directories with the setgid bit set, but this
+ * wasn't very useful and introduces the ability to escalate privileges to
+ * that group:
+ * https://www.halfdog.net/Security/2015/SetgidDirectoryPrivilegeEscalation/
+ */
+static void fix_permissions (const char *dir)
+{
+ struct stat st;
+
+ if (stat (dir, &st) == 0) {
+ if ((st.st_mode & S_ISGID) != 0) {
+ int status;
+
+ debug ("removing setgid bit from %s\n", dir);
+ status = chmod (dir, st.st_mode & ~S_ISGID);
+ if (status)
+ error (0, errno, _("can't chmod %s"), dir);
+ }
+
+ chown_if_possible (dir);
+ }
+}
+
+static void fix_permissions_tree (const char *catdir)
+{
+ if (is_directory (catdir) == 1) {
+ char *catname;
+ int i;
+
+ fix_permissions (catdir);
+ catname = xasprintf ("%s/cat1", catdir);
+ assert (catname);
+ for (i = 1; i <= 9; ++i) {
+ catname[strlen (catname) - 1] = '0' + i;
+ fix_permissions (catname);
+ }
+ free (catname);
+ }
+}
+
+/*
+ * accepts the raw man dir tree eg. "/usr/man" and the time stored in the db
+ * any dirs of the tree that have been modified (ie added to) will then be
+ * scanned for new files, which are then added to the db.
+ */
+static int testmandirs (MYDBM_FILE dbf, const char *path, const char *catpath,
+ struct timespec last, bool create)
+{
+ DIR *dir;
+ struct dirent *mandir;
+ int amount = 0;
+ bool created = false;
+
+ debug ("Testing %s for new files\n", path);
+
+ if (catpath)
+ fix_permissions_tree (catpath);
+
+ dir = opendir (path);
+ if (!dir) {
+ error (0, errno, _("can't search directory %s"), path);
+ return 0;
+ }
+
+ if (chdir (path) != 0) {
+ error (0, errno, _("can't change to directory %s"), path);
+ closedir (dir);
+ return 0;
+ }
+
+ while( (mandir = readdir (dir)) ) {
+ struct stat stbuf;
+ struct timespec mtime;
+
+ if (strncmp (mandir->d_name, "man", 3) != 0)
+ continue;
+
+ debug ("Examining %s\n", mandir->d_name);
+
+ if (stat (mandir->d_name, &stbuf) != 0) /* stat failed */
+ continue;
+ if (!S_ISDIR(stbuf.st_mode)) /* not a directory */
+ continue;
+ mtime = get_stat_mtime (&stbuf);
+ if (last.tv_sec && timespec_cmp (mtime, last) <= 0) {
+ /* scanned already */
+ debug ("%s modified %ld.%09ld, "
+ "db modified %ld.%09ld\n",
+ mandir->d_name,
+ (long) mtime.tv_sec, (long) mtime.tv_nsec,
+ (long) last.tv_sec, (long) last.tv_nsec);
+ continue;
+ }
+
+ debug ("\tsubdirectory %s has been 'modified'\n",
+ mandir->d_name);
+
+ if (create && !created) {
+ /* We seem to have something to do, so create the
+ * database now.
+ */
+ mkcatdirs (path, catpath);
+
+ /* Open the db in CTRW mode to store the $ver$ ID */
+
+ if (!MYDBM_CTRWOPEN (dbf)) {
+ if (errno == EACCES || errno == EROFS) {
+ debug ("database %s is read-only\n",
+ dbf->name);
+ closedir (dir);
+ return 0;
+ } else {
+ error (0, errno,
+ _("can't create index cache %s"),
+ dbf->name);
+ closedir (dir);
+ return -1;
+ }
+ }
+
+ dbver_wr (dbf);
+
+ created = true;
+ } else if (!ensure_db_open (dbf)) {
+ gripe_rwopen_failed (dbf);
+ closedir (dir);
+ return 0;
+ }
+
+ if (!quiet) {
+ int tty = isatty (STDERR_FILENO);
+
+ if (tty)
+ fprintf (stderr, "\r");
+ fprintf (stderr,
+ _("Updating index cache for path "
+ "`%s/%s'. Wait..."), path, mandir->d_name);
+ if (!tty)
+ fprintf (stderr, "\n");
+ }
+ add_dir_entries (dbf, path, mandir->d_name);
+ amount++;
+ }
+ closedir (dir);
+
+ return amount;
+}
+
+/* routine to prepare/create the db prior to calling testmandirs() */
+int create_db (MYDBM_FILE dbf, const char *manpath, const char *catpath)
+{
+ struct timespec time_zero;
+ int amount;
+
+ debug ("create_db(%s): %s\n", manpath, dbf->name);
+
+ time_zero.tv_sec = 0;
+ time_zero.tv_nsec = 0;
+ amount = testmandirs (dbf, manpath, catpath, time_zero, true);
+
+ if (amount > 0 && !quiet)
+ fputs (_("done.\n"), stderr);
+
+ return amount;
+}
+
+/* Make sure an existing database is essentially sane. */
+static bool sanity_check_db (MYDBM_FILE dbf)
+{
+ datum key;
+
+ if (dbver_rd (dbf))
+ return false;
+
+ key = MYDBM_FIRSTKEY (dbf);
+ while (MYDBM_DPTR (key) != NULL) {
+ datum content, nextkey;
+
+ content = MYDBM_FETCH (dbf, key);
+ if (!MYDBM_DPTR (content)) {
+ debug ("warning: %s has a key with no content (%s); "
+ "rebuilding\n", dbf->name, MYDBM_DPTR (key));
+ MYDBM_FREE_DPTR (key);
+ return false;
+ }
+#pragma GCC diagnostic push
+#if GNUC_PREREQ(10,0)
+# pragma GCC diagnostic ignored "-Wanalyzer-double-free"
+#endif
+ MYDBM_FREE_DPTR (content);
+ nextkey = MYDBM_NEXTKEY (dbf, key);
+ MYDBM_FREE_DPTR (key);
+#pragma GCC diagnostic pop
+ key = nextkey;
+ }
+
+ return true;
+}
+
+/* routine to update the db, ensure that it is consistent with the
+ filesystem */
+int update_db (MYDBM_FILE dbf, const char *manpath, const char *catpath)
+{
+ struct timespec mtime;
+ int new;
+
+ if (!ensure_db_open (dbf) || !sanity_check_db (dbf)) {
+ debug ("failed to open %s O_RDONLY\n", dbf->name);
+ return -1;
+ }
+ mtime = MYDBM_GET_TIME (dbf);
+
+ debug ("update_db(): %ld.%09ld\n",
+ (long) mtime.tv_sec, (long) mtime.tv_nsec);
+ new = testmandirs (dbf, manpath, catpath, mtime, false);
+
+ if (new > 0 && !quiet)
+ fputs (_("done.\n"), stderr);
+
+ return new;
+}
+
+/* Purge any entries pointing to name. This currently assumes that pointers
+ * are always shallow, which may not be a good assumption yet; it should be
+ * close, though.
+ */
+void purge_pointers (MYDBM_FILE dbf, const char *name)
+{
+ datum key = MYDBM_FIRSTKEY (dbf);
+
+ debug ("Purging pointers to vanished page \"%s\"\n", name);
+
+ while (MYDBM_DPTR (key) != NULL) {
+ datum content, nextkey;
+ struct mandata *entry = NULL;
+ char *nicekey, *tab;
+
+#pragma GCC diagnostic push
+#if GNUC_PREREQ(10,0)
+# pragma GCC diagnostic ignored "-Wanalyzer-use-after-free"
+#endif
+ /* Ignore db identifier keys. */
+ if (*MYDBM_DPTR (key) == '$')
+ goto pointers_next;
+#pragma GCC diagnostic pop
+
+ content = MYDBM_FETCH (dbf, key);
+ if (!MYDBM_DPTR (content))
+ return;
+
+ /* Get just the name. */
+ nicekey = xstrdup (MYDBM_DPTR (key));
+ tab = strchr (nicekey, '\t');
+ if (tab)
+ *tab = '\0';
+
+#pragma GCC diagnostic push
+#if GNUC_PREREQ(10,0)
+# pragma GCC diagnostic ignored "-Wanalyzer-use-after-free"
+#endif
+ if (*MYDBM_DPTR (content) == '\t')
+ goto pointers_contentnext;
+#pragma GCC diagnostic pop
+
+ entry = split_content (dbf, MYDBM_DPTR (content));
+ if (entry->id != SO_MAN && entry->id != WHATIS_MAN)
+ goto pointers_contentnext;
+
+ if (STREQ (entry->pointer, name)) {
+ if (!opt_test)
+ dbdelete (dbf, nicekey, entry);
+ else
+ debug ("%s(%s): pointer vanished, "
+ "would delete\n", nicekey, entry->ext);
+ }
+
+pointers_contentnext:
+ free_mandata_struct (entry);
+ free (nicekey);
+ MYDBM_FREE_DPTR (content);
+pointers_next:
+ nextkey = MYDBM_NEXTKEY (dbf, key);
+ MYDBM_FREE_DPTR (key);
+ key = nextkey;
+ }
+}
+
+/* Count the number of exact extension matches returned from look_for_file()
+ * (which may return inexact extension matches in some cases). It may turn
+ * out that this is better handled in look_for_file() itself.
+ */
+static int count_glob_matches (const char *ext, gl_list_t source,
+ struct timespec db_mtime)
+{
+ const char *walk;
+ int count = 0;
+
+ GL_LIST_FOREACH (source, walk) {
+ struct mandata *info;
+ struct stat statbuf;
+
+ if (stat (walk, &statbuf) == -1) {
+ debug ("count_glob_matches: excluding %s "
+ "because stat failed\n", walk);
+ continue;
+ }
+ if (db_mtime.tv_sec != (time_t) -1 &&
+ timespec_cmp (get_stat_mtime (&statbuf), db_mtime) <= 0) {
+ debug ("count_glob_matches: excluding %s, "
+ "no newer than database\n", walk);
+ continue;
+ }
+
+ info = filename_info (walk, quiet < 2);
+ if (info) {
+ if (STREQ (ext, info->ext))
+ ++count;
+ free_mandata_struct (info);
+ }
+ }
+
+ return count;
+}
+
+/* Decide whether to purge a reference to a "normal" (ULT_MAN or SO_MAN)
+ * page.
+ */
+static int purge_normal (MYDBM_FILE dbf, const char *name,
+ struct mandata *info, gl_list_t found)
+{
+ struct timespec t;
+
+ /* TODO: On some systems, the cat page extension differs from the
+ * man page extension, so this may be too strict.
+ */
+ t.tv_sec = -1;
+ t.tv_nsec = -1;
+ if (count_glob_matches (info->ext, found, t))
+ return 0;
+
+ if (!opt_test)
+ dbdelete (dbf, name, info);
+ else
+ debug ("%s(%s): missing page, would delete\n",
+ name, info->ext);
+
+ return 1;
+}
+
+/* Decide whether to purge a reference to a WHATIS_MAN or WHATIS_CAT page. */
+static int purge_whatis (MYDBM_FILE dbf, const char *path, bool cat,
+ const char *name, struct mandata *info,
+ gl_list_t found, struct timespec db_mtime)
+{
+ /* TODO: On some systems, the cat page extension differs from the
+ * man page extension, so this may be too strict.
+ */
+ if (count_glob_matches (info->ext, found, db_mtime)) {
+ /* If the page exists and didn't beforehand, then presumably
+ * we're about to rescan, which will replace the WHATIS_MAN
+ * entry with something better. However, there have been
+ * bugs that created false WHATIS_MAN entries, so force the
+ * rescan just to be sure; since in the absence of a bug we
+ * would rescan anyway, this isn't a problem.
+ */
+ if (!force_rescan)
+ debug ("%s(%s): whatis replaced by real page; "
+ "forcing a rescan just in case\n",
+ name, info->ext);
+ force_rescan = true;
+ return 0;
+ } else if (STREQ (info->pointer, "-")) {
+ /* This is broken; a WHATIS_MAN should never have an empty
+ * pointer field. This might have happened due to the first
+ * name in a page being different from what the file name
+ * says; that's fixed now, so delete and force a rescan.
+ */
+ if (!opt_test)
+ dbdelete (dbf, name, info);
+ else
+ debug ("%s(%s): whatis with empty pointer, "
+ "would delete\n", name, info->ext);
+
+ if (!force_rescan)
+ debug ("%s(%s): whatis had empty pointer; "
+ "forcing a rescan just in case\n",
+ name, info->ext);
+ force_rescan = true;
+ return 1;
+ } else {
+ /* Does the real page still exist? */
+ gl_list_t real_found;
+ bool save_debug = debug_level;
+ struct timespec t;
+ int count;
+
+ debug_level = false;
+ real_found = look_for_file (path, info->ext,
+ info->pointer, cat, LFF_MATCHCASE);
+ debug_level = save_debug;
+
+ t.tv_sec = -1;
+ t.tv_nsec = -1;
+ count = count_glob_matches (info->ext, real_found, t);
+ gl_list_free (real_found);
+ if (count)
+ return 0;
+
+ if (!opt_test)
+ dbdelete (dbf, name, info);
+ else
+ debug ("%s(%s): whatis target was deleted, "
+ "would delete\n", name, info->ext);
+ return 1;
+ }
+}
+
+/* Check that multi keys are correctly constructed. */
+static bool check_multi_key (const char *name, const char *content)
+{
+ const char *walk, *next;
+
+ if (!*content)
+ return false;
+
+ for (walk = content; walk && *walk; walk = next) {
+ /* The name in the multi key should only differ from the
+ * name of the key itself in its case, if at all.
+ */
+ bool valid = true;
+ ++walk; /* skip over initial tab */
+ next = strchr (walk, '\t');
+ if (next) {
+ if (strncasecmp (name, walk, next - walk))
+ valid = false;
+ } else {
+ if (strcasecmp (name, walk))
+ valid = false;
+ }
+ if (!valid) {
+ debug ("%s: broken multi key \"%s\", "
+ "forcing a rescan\n", name, content);
+ force_rescan = true;
+ return true;
+ }
+
+ /* If the name was valid, skip over the extension and
+ * continue the scan.
+ */
+ walk = next;
+ next = walk ? strchr (walk + 1, '\t') : NULL;
+ }
+
+ return false;
+}
+
+/* Go through the database and purge references to man pages that no longer
+ * exist.
+ */
+int purge_missing (MYDBM_FILE dbf, const char *manpath, const char *catpath)
+{
+#ifdef NDBM
+ char *dirfile;
+#endif
+ struct stat st;
+ bool db_exists;
+ datum key;
+ int count = 0;
+ struct timespec db_mtime;
+
+#ifdef NDBM
+ dirfile = xasprintf ("%s.dir", dbf->name);
+ db_exists = stat (dirfile, &st) == 0;
+ free (dirfile);
+#else
+ db_exists = stat (dbf->name, &st) == 0;
+#endif
+ if (!db_exists)
+ /* nothing to purge */
+ return 0;
+
+ if (!quiet)
+ printf (_("Purging old database entries in %s...\n"), manpath);
+
+ if (!ensure_db_open (dbf) || !sanity_check_db (dbf)) {
+ gripe_rwopen_failed (dbf);
+ return 0;
+ }
+ db_mtime = MYDBM_GET_TIME (dbf);
+
+ key = MYDBM_FIRSTKEY (dbf);
+
+ while (MYDBM_DPTR (key) != NULL) {
+ datum content, nextkey;
+ struct mandata *entry;
+ char *nicekey, *tab;
+ bool save_debug;
+ gl_list_t found;
+
+#pragma GCC diagnostic push
+#if GNUC_PREREQ(10,0)
+# pragma GCC diagnostic ignored "-Wanalyzer-use-after-free"
+#endif
+ /* Ignore db identifier keys. */
+ if (*MYDBM_DPTR (key) == '$') {
+ nextkey = MYDBM_NEXTKEY (dbf, key);
+ MYDBM_FREE_DPTR (key);
+ key = nextkey;
+ continue;
+ }
+#pragma GCC diagnostic pop
+
+ content = MYDBM_FETCH (dbf, key);
+ if (!MYDBM_DPTR (content)) {
+ nextkey = MYDBM_NEXTKEY (dbf, key);
+ MYDBM_FREE_DPTR (key);
+ key = nextkey;
+ continue;
+ }
+
+ /* Get just the name. */
+ nicekey = xstrdup (MYDBM_DPTR (key));
+ tab = strchr (nicekey, '\t');
+ if (tab)
+ *tab = '\0';
+
+#pragma GCC diagnostic push
+#if GNUC_PREREQ(10,0)
+# pragma GCC diagnostic ignored "-Wanalyzer-use-after-free"
+#endif
+ /* Deal with multi keys. */
+ if (*MYDBM_DPTR (content) == '\t') {
+ if (check_multi_key (nicekey, MYDBM_DPTR (content)))
+ MYDBM_DELETE (dbf, key);
+ free (nicekey);
+ MYDBM_FREE_DPTR (content);
+ nextkey = MYDBM_NEXTKEY (dbf, key);
+ MYDBM_FREE_DPTR (key);
+ key = nextkey;
+ continue;
+ }
+#pragma GCC diagnostic pop
+
+ entry = split_content (dbf, MYDBM_DPTR (content));
+
+ save_debug = debug_level;
+ debug_level = false; /* look_for_file() is quite noisy */
+ if (entry->id <= WHATIS_MAN)
+ found = look_for_file (manpath, entry->ext,
+ entry->name ? entry->name
+ : nicekey,
+ false, LFF_MATCHCASE);
+ else
+ found = look_for_file (catpath, entry->ext,
+ entry->name ? entry->name
+ : nicekey,
+ true, LFF_MATCHCASE);
+ debug_level = save_debug;
+
+ /* Now actually decide whether to purge, depending on the
+ * type of entry.
+ */
+ if (entry->id == ULT_MAN || entry->id == SO_MAN ||
+ entry->id == STRAY_CAT)
+ count += purge_normal (dbf, nicekey, entry, found);
+ else if (entry->id == WHATIS_MAN)
+ count += purge_whatis (dbf, manpath, false, nicekey,
+ entry, found, db_mtime);
+ else /* entry->id == WHATIS_CAT */
+ count += purge_whatis (dbf, catpath, true, nicekey,
+ entry, found, db_mtime);
+
+ gl_list_free (found);
+ free (nicekey);
+
+ free_mandata_struct (entry);
+ MYDBM_FREE_DPTR (content);
+ nextkey = MYDBM_NEXTKEY (dbf, key);
+ MYDBM_FREE_DPTR (key);
+ key = nextkey;
+ }
+
+ return count;
+}