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+/*
+ * ult_src.c: Find the ultimate source of a page
+ *
+ * Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
+ * Copyright (C) 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011,
+ * 2012 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
+ *
+ * code to seek out the original (ultimate) source man file for
+ * any specified man file. Soft and hard links and .so inclusions
+ * are traced. Use: reduce amount of cat files to a minimum.
+ *
+ * Mon May 2 11:14:28 BST 1994 Wilf. (G.Wilford@ee.surrey.ac.uk)
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <assert.h>
+#include <dirent.h>
+#include <unistd.h>
+
+#include "canonicalize.h"
+#include "dirname.h"
+#include "error.h"
+#include "xvasprintf.h"
+
+#include "gettext.h"
+#define _(String) gettext (String)
+
+#include "manconfig.h"
+
+#include "pipeline.h"
+#include "decompress.h"
+
+#include "globbing.h"
+#include "ult_src.h"
+
+/* Find minimum value hard link filename for given file and inode.
+ * Returns a newly allocated string.
+ */
+static char *ult_hardlink (const char *fullpath, ino_t inode)
+{
+ DIR *mdir;
+ struct dirent *manlist;
+ char *base, *dir, *ret;
+ const char *slash;
+
+ slash = strrchr (fullpath, '/');
+ assert (slash);
+ dir = xstrndup (fullpath, slash - fullpath);
+ base = xstrdup (++slash);
+
+ mdir = opendir (dir);
+ if (mdir == NULL) {
+ if (quiet < 2)
+ error (0, errno, _("can't search directory %s"), dir);
+ free (dir);
+ free (base);
+ return NULL;
+ }
+
+ while ((manlist = readdir (mdir))) {
+ if (manlist->d_ino == inode &&
+ strcmp (base, manlist->d_name) > 0) {
+ free (base);
+ base = xstrdup (manlist->d_name);
+ debug ("ult_hardlink: (%s)\n", base);
+ }
+ }
+ closedir (mdir);
+
+ /* If we already are the link with the smallest name value */
+ /* return NULL */
+
+ if (strcmp (base, slash) == 0) {
+ free (dir);
+ free (base);
+ return NULL;
+ }
+
+ ret = xasprintf ("%s/%s", dir, base);
+ free (dir);
+ free (base);
+ return ret;
+}
+
+/* Resolve all symbolic links within 'fullpath'.
+ * Returns a newly allocated string.
+ */
+static char *ult_softlink (const char *fullpath)
+{
+ char *resolved_path;
+
+ resolved_path = canonicalize_file_name (fullpath);
+ if (!resolved_path) {
+ /* discard the unresolved path */
+ if (quiet < 2) {
+ if (errno == ENOENT)
+ error (0, 0,
+ _("warning: %s is a dangling symlink"),
+ fullpath);
+ else
+ error (0, errno, _("can't resolve %s"),
+ fullpath);
+ }
+ return NULL;
+ }
+
+ debug ("ult_softlink: (%s)\n", resolved_path);
+
+ return resolved_path;
+}
+
+/* Test 'buffer' to see if it contains a .so include. If so and it's not an
+ * absolute filename, return newly allocated string whose contents are the
+ * include.
+ */
+static char *test_for_include (const char *buffer)
+{
+ if (!buffer)
+ return NULL;
+
+ /* strip out any leading whitespace (if any) */
+ while (CTYPE (isspace, *buffer))
+ buffer++;
+
+ /* see if the `command' is a .so */
+ if (strncmp (buffer, ".so", 3) == 0) {
+ buffer += 3;
+
+ /* strip out any whitespace between the command and
+ it's argumant */
+ while (CTYPE (isspace, *buffer))
+ buffer++;
+
+ /* If .so's argument is an absolute filename, it could be
+ * either (i) a macro inclusion, (ii) a non local manual page
+ * or (iii) a (somewhat bogus) reference to a local manual
+ * page.
+ *
+ * If (i) or (ii), we must not follow the reference. (iii) is
+ * a problem with the manual page, thus we don't want to
+ * follow any absolute inclusions in our quest for the
+ * ultimate source file */
+ if (*buffer != '/') {
+ const char *end = buffer;
+ while (*end && !CTYPE (isspace, *end))
+ ++end;
+ return xstrndup (buffer, end - buffer);
+ }
+ }
+ return NULL;
+}
+
+static char *find_include (const char *name, const char *path,
+ const char *include)
+{
+ char *ret;
+ char *dirname;
+ char *temp_file;
+
+ /* Restore the original path from before ult_softlink() etc., in
+ * case it went outside the mantree.
+ */
+ ret = xasprintf ("%s/%s", path, include);
+
+ /* If the original path from above doesn't exist, try to create new
+ * path as if the "include" was relative to the current man page.
+ */
+ if (CAN_ACCESS (ret, F_OK))
+ return ret;
+
+ dirname = dir_name (name);
+ temp_file = xasprintf ("%s/%s", dirname, include);
+ free (dirname);
+
+ if (CAN_ACCESS (temp_file, F_OK)) {
+ /* Just plain include. */
+ free (ret);
+ ret = canonicalize_file_name (temp_file);
+ } else {
+ /* Try globbing - the file suffix might be missing. */
+ char *temp_file_asterisk = xasprintf ("%s*", temp_file);
+ char **candidate_files = expand_path (temp_file_asterisk);
+ int i;
+
+ free (temp_file_asterisk);
+ if (CAN_ACCESS (candidate_files[0], F_OK)) {
+ free (ret);
+ ret = canonicalize_file_name (candidate_files[0]);
+ }
+ for (i = 0; candidate_files[i]; i++)
+ free (candidate_files[i]);
+ free (candidate_files);
+ }
+ free (temp_file);
+
+ return ret;
+}
+
+static void ult_trace (struct ult_trace *trace, const char *s)
+{
+ if (!trace)
+ return;
+ if (trace->len >= trace->max) {
+ trace->max *= 2;
+ trace->names = xnrealloc (trace->names, trace->max,
+ sizeof (char *));
+ }
+ trace->names[trace->len++] = xstrdup (s);
+}
+
+void free_ult_trace (struct ult_trace *trace)
+{
+ size_t i;
+ for (i = 0; i < trace->len; ++i)
+ free (trace->names[i]);
+ free (trace->names);
+}
+
+/*
+ * recursive function which finds the ultimate source file by following
+ * any ".so filename" directives in the first line of the man pages.
+ * Also (optionally) traces symlinks and hard links(!).
+ *
+ * name is full pathname, path is the MANPATH directory (/usr/man)
+ * flags is a combination of SO_LINK | SOFT_LINK | HARD_LINK
+ */
+const char *ult_src (const char *name, const char *path,
+ struct stat *buf, int flags, struct ult_trace *trace)
+{
+ static char *base; /* must be static */
+ static short recurse; /* must be static */
+
+ /* initialise the function */
+
+ if (trace) {
+ if (!trace->names) {
+ trace->len = 0;
+ trace->max = 16;
+ trace->names = XNMALLOC (trace->max, char *);
+ }
+ ult_trace (trace, name);
+ }
+
+ /* as ult_softlink() & ult_hardlink() do all of their respective
+ * resolving in one call, only need to sort them out once
+ */
+
+ if (recurse == 0) {
+ struct stat new_buf;
+ free (base);
+ base = xstrdup (name);
+
+ debug ("\nult_src: File %s in mantree %s\n", name, path);
+
+ /* If we don't have a buf, allocate and assign one */
+ if (!buf && ((flags & SOFT_LINK) || (flags & HARD_LINK))) {
+ buf = &new_buf;
+ if (lstat (base, buf) == -1) {
+ if (quiet < 2)
+ error (0, errno, _("can't resolve %s"),
+ base);
+ return NULL;
+ }
+ }
+
+ /* Permit semi local (inter-tree) soft links */
+ if (flags & SOFT_LINK) {
+ assert (buf); /* initialised above */
+ if (S_ISLNK (buf->st_mode)) {
+ /* Is a symlink, resolve it. */
+ char *softlink = ult_softlink (base);
+ if (softlink) {
+ free (base);
+ base = softlink;
+ } else
+ return NULL;
+ }
+ }
+
+ /* Only deal with local (inter-dir) HARD links */
+ if (flags & HARD_LINK) {
+ assert (buf); /* initialised above */
+ if (buf->st_nlink > 1) {
+ /* Has HARD links, find least value */
+ char *hardlink = ult_hardlink (base,
+ buf->st_ino);
+ if (hardlink) {
+ free (base);
+ base = hardlink;
+ }
+ }
+ }
+ }
+
+ /* keep a check on recursion level */
+ else if (recurse == 10) {
+ if (quiet < 2)
+ error (0, 0, _("%s is self referencing"), name);
+ return NULL;
+ }
+
+ if (flags & SO_LINK) {
+ const char *buffer;
+ char *decomp_base;
+ pipeline *decomp;
+ char *include;
+#ifdef COMP_SRC
+ struct stat st;
+
+ if (stat (base, &st) < 0) {
+ struct compression *comp = comp_file (base);
+
+ if (comp) {
+ free (base);
+ base = comp->stem;
+ comp->stem = NULL; /* steal memory */
+ } else {
+ if (quiet < 2)
+ error (0, errno, _("can't open %s"),
+ base);
+ return NULL;
+ }
+ }
+#endif
+
+ /* base may change for recursive calls to ult_src, but
+ * decompress_open doesn't keep its own copy.
+ */
+ decomp_base = xstrdup (base);
+ decomp = decompress_open (decomp_base);
+ if (!decomp) {
+ if (quiet < 2)
+ error (0, errno, _("can't open %s"), base);
+ free (decomp_base);
+ return NULL;
+ }
+ pipeline_start (decomp);
+
+ /* make sure that we skip over any comments */
+ do {
+ buffer = pipeline_readline (decomp);
+ } while (buffer && STRNEQ (buffer, ".\\\"", 3));
+
+ include = test_for_include (buffer);
+ if (include) {
+ char *new_name;
+ const char *ult;
+
+ free (base);
+ base = find_include (name, path, include);
+ free (include);
+
+ debug ("ult_src: points to %s\n", base);
+
+ recurse++;
+ /* Take a copy; it's unwise to pass base directly to
+ * a recursive call, as it may be freed.
+ */
+ new_name = xstrdup (base);
+ ult = ult_src (new_name, path, NULL, flags, trace);
+ free (new_name);
+ recurse--;
+
+ pipeline_wait (decomp);
+ pipeline_free (decomp);
+ free (decomp_base);
+ return ult;
+ }
+
+ pipeline_wait (decomp);
+ pipeline_free (decomp);
+ free (decomp_base);
+ }
+
+ /* We have the ultimate source */
+ if (trace)
+ ult_trace (trace, base);
+ return base;
+}
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