1 files changed, 149 insertions, 0 deletions
diff --git a/src/libbb/gz_open.c b/src/libbb/gz_open.c
new file mode 100644
index 0000000..bdc7564
--- /dev/null
+++ b/src/libbb/gz_open.c
@@ -0,0 +1,149 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) many different people.  If you wrote this, please
+ * acknowledge your work.
+ *
+ * This program 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 program 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "libbb.h"
+
+static int gz_use_vfork;
+
+FILE *
+gz_open(FILE *compressed_file, int *pid)
+{
+	int unzip_pipe[2];
+	off_t floc;
+	int cfile = -1;
+
+	gz_use_vfork = (getenv("OPKG_USE_VFORK") != NULL);
+
+	if (gz_use_vfork) {
+		/* Create a new file descriptor for the input stream
+		 * (it *must* be associated with a file), and lseek()
+		 * to the same position in that fd as the stream.
+		 */
+		cfile = dup(fileno(compressed_file));
+		floc = ftello(compressed_file);
+		lseek(cfile, floc, SEEK_SET);
+		setenv("GZIP", "--quiet", 0);
+	}
+
+	if (pipe(unzip_pipe)!=0) {
+		perror_msg("pipe");
+		return(NULL);
+	}
+
+	/* If we don't flush, we end up with two copies of anything pending,
+	   one from the parent, one from the child */
+	fflush(stdout);
+	fflush(stderr);
+
+	if (gz_use_vfork) {
+		*pid = vfork();
+	} else {
+		*pid = fork();
+	}
+
+	if (*pid<0) {
+		perror_msg("fork");
+		return(NULL);
+	}
+
+	if (*pid==0) {
+		/* child process */
+		close(unzip_pipe[0]);
+		if (gz_use_vfork) {
+			dup2(unzip_pipe[1], 1);
+			dup2(cfile, 0);
+			execlp("gunzip","gunzip",NULL);
+			/* If we get here, we had a failure */
+			_exit(EXIT_FAILURE);
+		} else {
+			unzip(compressed_file, fdopen(unzip_pipe[1], "w"));
+			fflush(NULL);
+			fclose(compressed_file);
+			close(unzip_pipe[1]);
+			_exit(EXIT_SUCCESS);
+		}
+	}
+	/* Parent process is executing here */
+	if (gz_use_vfork) {
+		close(cfile);
+	}
+	close(unzip_pipe[1]);
+	return(fdopen(unzip_pipe[0], "r"));
+}
+
+int
+gz_close(int gunzip_pid)
+{
+	int status;
+	int ret;
+
+	if (gz_use_vfork) {
+		/* The gunzip process remains running in the background if we
+		 * used the vfork()/exec() technique - so we have to kill it
+		 * forcibly.  There might be a better way to do this, but that
+		 * affect a lot of other parts of opkg, and this works fine.
+		 */
+		if (kill(gunzip_pid, SIGTERM) == -1) {
+			perror_msg("gz_close(): unable to kill gunzip pid.");
+			return -1;
+		}
+	}
+
+
+	if (waitpid(gunzip_pid, &status, 0) == -1) {
+		perror_msg("waitpid");
+		return -1;
+	}
+
+	if (gz_use_vfork) {
+		/* Bail out here if we used the vfork()/exec() technique. */
+		return 0;
+	}
+
+	if (WIFSIGNALED(status)) {
+		error_msg("Unzip process killed by signal %d.\n",
+			WTERMSIG(status));
+		return -1;
+	}
+
+	if (!WIFEXITED(status)) {
+		/* shouldn't happen */
+		error_msg("Your system is broken: got status %d from waitpid.\n",
+				status);
+		return -1;
+	}
+
+	if ((ret = WEXITSTATUS(status))) {
+		error_msg("Unzip process failed with return code %d.\n",
+				ret);
+		return -1;
+	}
+
+	return 0;
+}