1 files changed, 75 insertions, 0 deletions
diff --git a/libbb/gz_open.c b/libbb/gz_open.c
index dbaf3bb..ba4d6a5 100644
--- a/libbb/gz_open.c
+++ b/libbb/gz_open.c
@@ -56,3 +56,78 @@ extern FILE *gz_open(FILE *compressed_file, int *pid)
 	}
 	return(fdopen(unzip_pipe[0], "r"));
 }
+
+/* gz_open implementation using gunzip and a vfork/exec -- dodges OOM killer */
+extern FILE *gzvopen(FILE *compressed_file, int *pid)
+{
+	int unzip_pipe[2];
+	off_t floc;
+	int cfile;
+
+	/* create a new file descriptor for the input stream
+	 * (it *must* be associated with a file)
+	 * and seek to the same position in that fd as the stream.
+	 */
+	cfile = dup(fileno(compressed_file));
+	floc = ftello(compressed_file);
+	lseek(cfile, floc, SEEK_SET);
+
+	/* create the pipe */
+	if (pipe(unzip_pipe)!=0) {
+		error_msg("gzvopen(): pipe error");
+		return(NULL);
+	}
+
+	*pid = vfork();
+
+	if (*pid < 0) {
+		error_msg("gzvopen(): fork failed");
+		return(NULL);
+	}
+
+	if (*pid==0) {
+		/* child process - reads STDIN, writes to pipe */
+
+		/* close unused read end of pipe */
+		close(unzip_pipe[0]);
+
+		/* connect child's stdout to the pipe write end */
+		dup2(unzip_pipe[1], 1);
+
+		/* connect child's stdin to the fd passed in to us */
+		dup2(cfile, 0);
+
+		/* execute the gunzip utility */
+		execlp("gunzip","gunzip",NULL);
+
+		/* if we get here, we had a failure - since we are
+		 * using vfork(), we cannot call exit(), must call _exit().
+		 */
+		_exit(-1);
+	}
+
+	/* Parent process is executing here */
+
+	/* we have no more need of the duplicate fd */
+	close(cfile);
+
+	/* close the write end of the pipe */
+	close(unzip_pipe[1]);
+
+	/* return the read end of the pipe as a FILE */
+	return(fdopen(unzip_pipe[0], "r"));
+}
+
+extern void gzvclose(int gunzip_pid)
+{
+        if (kill(gunzip_pid, SIGTERM) == -1) {
+		perror("gzvclose()");
+                fprintf(stderr,"%s: unable to kill gunzip pid.\n",
+			__FUNCTION__);
+        }
+
+        if (waitpid(gunzip_pid, NULL, 0) == -1) {
+                fprintf(stderr,"%s: unable to wait on gunzip pid.\n",
+			__FUNCTION__);
+        }
+}