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-rw-r--r--unrpm.c140
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+/*
+ * 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);
+}