1 files changed, 140 insertions, 0 deletions
diff --git a/unrpm.c b/unrpm.c
new file mode 100644
index 0000000..cfcc0d1
--- /dev/null
+++ b/unrpm.c
@@ -0,0 +1,140 @@
+/*
+ * Mini unrpm implementation for busybox
+ *
+ * rpmunpack.c  -  Utility program to unpack an RPM archive
+ *
+ * Gero Kuhlmann <gero@gkminix.han.de> 1998
+ *
+ *  This program is public domain software; you can do whatever you like
+ *  with this source, including modifying and redistributing it.
+ *
+ *  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.
+ */
+ 
+#include "internal.h" 
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+/*
+ * Some general definitions
+ */
+#define BUFSIZE		512
+#define RPM_MAGIC	"\355\253\356\333"
+#define GZ_MAGIC_1	'\037'
+#define GZ_MAGIC_2	'\213'
+
+/*
+ * Global variables
+ */
+static char buffer[BUFSIZE];
+static char *progname;
+static int infile, outfile;
+
+/*
+ * Read a specified number of bytes from input file
+ */
+static void myread(int num)
+{
+  int err;
+
+  if ((err = read(infile, buffer, num)) != num) {
+	if (err < 0)
+		perror(progname);
+	else
+		fprintf(stderr, "unexpected end of input file\n");
+	exit(1);
+  }
+}
+
+/*
+ * Main program
+ */
+int unrpm_main(int argc, char **argv)
+{
+  int len, status = 0;
+
+  /* Get our own program name */
+  if ((progname = strrchr(argv[0], '/')) == NULL)
+	progname = argv[0];
+  else
+	progname++;
+
+  /* Check for command line parameters */
+	if (argc>=2 && *argv[1]=='-') {
+           usage(unrpm_usage);
+	}
+
+  /* Open input file */
+  if (argc == 1)
+	infile = STDIN_FILENO;
+  else if ((infile = open(argv[1], O_RDONLY)) < 0) {
+	perror(progname);
+	exit(1);
+  }
+
+  /* Read magic ID and output filename */
+  myread(4);
+  if (strncmp(buffer, RPM_MAGIC, 4)) {
+	fprintf(stderr, "input file is not in RPM format\n");
+	exit(1);
+  }
+  myread(6);		/* Skip flags */
+  myread(64);
+  buffer[64] = '\0';
+
+  /* Open output file */
+  strcat(buffer, ".cpio.gz");
+  if (infile == STDIN_FILENO)
+	outfile = STDOUT_FILENO;
+  else if ((outfile = open(buffer, O_WRONLY | O_CREAT | O_TRUNC, 0644)) < 0) {
+	perror(progname);
+	exit(1);
+  }
+
+  /*
+   * Now search for the GZIP signature. This is rather awkward, but I don't
+   * know any other way how to find out the exact starting position of the
+   * archive within the input file. There are a couple of data structures
+   * and texts (obviously descriptions, installation shell scripts etc.)
+   * coming before the archive, but even they start at different offsets
+   * with different RPM files. However, it looks like the GZIP signature
+   * never appears before offset 0x200, so we skip these first couple of
+   * bytes to make the signature scan a little more reliable.
+   */
+  myread(0x200 - 74);
+  while (status < 2) {
+	myread(1);
+	if (status == 0 && buffer[0] == GZ_MAGIC_1)
+		status++;
+	else if (status == 1 && buffer[0] == GZ_MAGIC_2)
+		status++;
+	else
+		status = 0;
+  }
+  buffer[0] = GZ_MAGIC_1;
+  buffer[1] = GZ_MAGIC_2;
+  if (write(outfile, buffer, 2) < 0) {
+	perror(progname);
+	exit(1);
+  }
+
+  /* Now simply copy the GZIP archive into the output file */
+  while ((len = read(infile, buffer, BUFSIZE)) > 0) {
+	if (write(outfile, buffer, len) < 0) {
+		perror(progname);
+		exit(1);
+	}
+  }
+  if (len < 0) {
+	perror(progname);
+	exit(1);
+  }
+  close(outfile);
+  close(infile);
+  exit(0);
+}