2 * Mini unrpm implementation for busybox
4 * rpmunpack.c - Utility program to unpack an RPM archive
6 * Gero Kuhlmann <gero@gkminix.han.de> 1998
8 * This program is public domain software; you can do whatever you like
9 * with this source, including modifying and redistributing it.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
24 * Some general definitions
27 #define RPM_MAGIC "\355\253\356\333"
28 #define GZ_MAGIC_1 '\037'
29 #define GZ_MAGIC_2 '\213'
34 static char buffer[BUFSIZE];
35 static char *progname;
36 static int infile, outfile;
39 * Read a specified number of bytes from input file
41 static void myread(int num)
45 if ((err = read(infile, buffer, num)) != num) {
49 fprintf(stderr, "unexpected end of input file\n");
57 int unrpm_main(int argc, char **argv)
61 /* Get our own program name */
62 if ((progname = strrchr(argv[0], '/')) == NULL)
67 /* Check for command line parameters */
68 if (argc>=2 && *argv[1]=='-') {
74 infile = STDIN_FILENO;
75 else if ((infile = open(argv[1], O_RDONLY)) < 0) {
80 /* Read magic ID and output filename */
82 if (strncmp(buffer, RPM_MAGIC, 4)) {
83 fprintf(stderr, "input file is not in RPM format\n");
86 myread(6); /* Skip flags */
90 /* Open output file */
91 strcat(buffer, ".cpio.gz");
92 if (infile == STDIN_FILENO)
93 outfile = STDOUT_FILENO;
94 else if ((outfile = open(buffer, O_WRONLY | O_CREAT | O_TRUNC, 0644)) < 0) {
100 * Now search for the GZIP signature. This is rather awkward, but I don't
101 * know any other way how to find out the exact starting position of the
102 * archive within the input file. There are a couple of data structures
103 * and texts (obviously descriptions, installation shell scripts etc.)
104 * coming before the archive, but even they start at different offsets
105 * with different RPM files. However, it looks like the GZIP signature
106 * never appears before offset 0x200, so we skip these first couple of
107 * bytes to make the signature scan a little more reliable.
112 if (status == 0 && buffer[0] == GZ_MAGIC_1)
114 else if (status == 1 && buffer[0] == GZ_MAGIC_2)
119 buffer[0] = GZ_MAGIC_1;
120 buffer[1] = GZ_MAGIC_2;
121 if (write(outfile, buffer, 2) < 0) {
126 /* Now simply copy the GZIP archive into the output file */
127 while ((len = read(infile, buffer, BUFSIZE)) > 0) {
128 if (write(outfile, buffer, len) < 0) {