1 files changed, 218 insertions, 0 deletions
diff --git a/src/manconv_client.c b/src/manconv_client.c
new file mode 100644
index 0000000..7cdb1b8
--- /dev/null
+++ b/src/manconv_client.c
@@ -0,0 +1,218 @@
+/*
+ * manconv_client.c: use manconv in a pipeline
+ *
+ * Copyright (C) 2007, 2008, 2010 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
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "gl_array_list.h"
+#include "gl_xlist.h"
+#include "xalloc.h"
+#include "xvasprintf.h"
+
+#include "manconfig.h"
+
+#include "pipeline.h"
+
+#include "appendstr.h"
+#include "glcontainers.h"
+#include "sandbox.h"
+#include "security.h"
+
+#include "decompress.h"
+#include "manconv.h"
+#include "manconv_client.h"
+#include "utf8.h"
+
+extern man_sandbox *sandbox;
+
+struct manconv_codes {
+	gl_list_t from;
+	char *to;
+};
+
+static void manconv_stdin (void *data)
+{
+	struct manconv_codes *codes = data;
+	decompress *decomp;
+
+	decomp = decompress_fdopen (dup (STDIN_FILENO));
+	decompress_start (decomp);
+	if (manconv (decomp, codes->from, codes->to, NULL) != 0)
+		/* manconv already wrote an error message to stderr.  Just
+		 * exit non-zero.
+		 */
+		exit (FATAL);
+	decompress_wait (decomp);
+	decompress_free (decomp);
+}
+
+static void manconv_pre_exec (void *data)
+{
+	/* We must drop privileges before loading the sandbox, since our
+	 * seccomp filter doesn't allow setresuid and friends.
+	 */
+	drop_privs (NULL);
+	sandbox_load (data);
+}
+
+static void free_manconv_codes (void *data)
+{
+	struct manconv_codes *codes = data;
+
+	gl_list_free (codes->from);
+	free (codes->to);
+	free (codes);
+}
+
+void add_manconv (pipeline *p,
+		  const char *source_encoding, const char *target_encoding)
+{
+	struct manconv_codes *codes;
+	char *name;
+	pipecmd *cmd;
+
+	if (STREQ (source_encoding, target_encoding))
+		return;
+
+	codes = xmalloc (sizeof *codes);
+	/* informational only; no shell quoting concerns */
+	name = xasprintf ("%s -f ", MANCONV);
+	codes->from = new_string_list (GL_ARRAY_LIST, true);
+	if (STREQ (source_encoding, "UTF-8")) {
+		gl_list_add_last (codes->from, xstrdup (source_encoding));
+		name = appendstr (name, source_encoding, (void *) 0);
+	} else {
+		gl_list_add_last (codes->from, xstrdup ("UTF-8"));
+		gl_list_add_last (codes->from, xstrdup (source_encoding));
+		name = appendstr (name, "UTF-8:", source_encoding, (void *) 0);
+	}
+	codes->to = xasprintf ("%s//IGNORE", target_encoding);
+	/* informational only; no shell quoting concerns */
+	name = appendstr (name, " -t ", codes->to, (void *) 0);
+	if (quiet >= 2)
+		name = appendstr (name, " -q", (void *) 0);
+
+	/* iconv_open may not work correctly in setuid processes; in GNU
+	 * libc, gconv modules may be linked against other gconv modules and
+	 * rely on RPATH $ORIGIN to load those modules from the correct
+	 * path, but $ORIGIN is disabled in setuid processes.  It is
+	 * impossible to reset libc's idea of setuidness without creating a
+	 * whole new process image.  Therefore, if the calling process is
+	 * setuid, we must drop privileges and execute manconv.
+	 */
+	if (running_setuid ()) {
+		gl_list_t from = codes->from;
+		const char *from_code;
+		char *sources = NULL;
+
+		cmd = pipecmd_new_args (MANCONV, "-f", (void *) 0);
+		GL_LIST_FOREACH (from, from_code) {
+			sources = appendstr (sources, from_code, (void *) 0);
+			if (gl_list_next_node (from, from_node))
+				sources = appendstr (sources, ":", (void *) 0);
+		}
+		pipecmd_arg (cmd, sources);
+		free (sources);
+		pipecmd_args (cmd, "-t", codes->to, (void *) 0);
+		if (quiet >= 2)
+			pipecmd_arg (cmd, "-q");
+		pipecmd_pre_exec (cmd, manconv_pre_exec, sandbox_free,
+				  sandbox);
+		free_manconv_codes (codes);
+	} else {
+		cmd = pipecmd_new_function (name, &manconv_stdin,
+					    &free_manconv_codes, codes);
+		pipecmd_pre_exec (cmd, sandbox_load, sandbox_free, sandbox);
+	}
+	free (name);
+	pipeline_command (p, cmd);
+}
+
+/* Convert the result of in-process decompression to a target encoding.
+ *
+ * This converts the buffered result of decompression to a new buffer, then
+ * replaces the decompress object's buffer with the converted one for use by
+ * later stages of processing.
+ *
+ * Returns zero on success or non-zero on failure.
+ */
+int manconv_inprocess (decompress *d,
+		       const char *source_encoding,
+		       const char *target_encoding)
+{
+	gl_list_t from;
+	char *to;
+	struct manconv_outbuf outbuf;
+	int ret = 0;
+
+	if (STREQ (source_encoding, target_encoding))
+		return 0;
+
+	from = new_string_list (GL_ARRAY_LIST, true);
+	if (STREQ (source_encoding, "UTF-8"))
+		gl_list_add_last (from, xstrdup (source_encoding));
+	else {
+		if (STREQ (target_encoding, "UTF-8")) {
+			/* If the target encoding is UTF-8, then instead of
+			 * starting with trial conversion from UTF-8 to
+			 * UTF-8, we can start by simply performing UTF-8
+			 * validation, avoiding a copy.  (The source
+			 * encoding cannot be UTF-8 in this case, since we
+			 * already checked that the source and target
+			 * encodings are different.)
+			 */
+			if (utf8_validate_len (decompress_inprocess_buf (d),
+					       decompress_inprocess_len (d)))
+				goto out;
+		} else
+			gl_list_add_last (from, xstrdup ("UTF-8"));
+		gl_list_add_last (from, xstrdup (source_encoding));
+	}
+	to = xasprintf ("%s//IGNORE", target_encoding);
+
+	outbuf.len = 0;
+	/* UTF-8 uses at most four bytes per Unicode code point.  We assume
+	 * that this conversion will be no worse than 1:4.
+	 */
+	outbuf.max = decompress_inprocess_len (d) * 4;
+	outbuf.buf = xmalloc (outbuf.max);
+
+	if (manconv (d, from, to, &outbuf) == 0)
+		decompress_inprocess_replace (d, outbuf.buf, outbuf.len);
+	else {
+		/* manconv already wrote an error message to stderr.  Just
+		 * return non-zero.
+		 */
+		free (outbuf.buf);
+		ret = -1;
+	}
+
+	free (to);
+out:
+	gl_list_free (from);
+	return ret;
+}