| /* |
| * 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 "busybox.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); |
| } |