/* * rpmunpack 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 <fcntl.h> #include <unistd.h> #include <string.h> #include <stdlib.h> #include "busybox.h" /* * Some general definitions */ #define RPM_MAGIC "\355\253\356\333" #define GZ_MAGIC_1 '\037' #define GZ_MAGIC_2 '\213' /* * Global variables */ static char *progname; static int infile, outfile; /* * Read a specified number of bytes from input file */ static void myread(int num, char *buffer) { int err; if ((err = read(infile, buffer, num)) != num) { if (err < 0) perror_msg_and_die(progname); else error_msg_and_die("Unexpected end of input file!"); } } /* * Main program */ int rpmunpack_main(int argc, char **argv) { int len, status = 0; RESERVE_BB_BUFFER(buffer, BUFSIZ); /* 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]=='-') { show_usage(); } /* Open input file */ if (argc == 1) infile = STDIN_FILENO; else if ((infile = open(argv[1], O_RDONLY)) < 0) perror_msg_and_die("%s", argv[1]); /* Read magic ID and output filename */ myread(4, buffer); if (strncmp(buffer, RPM_MAGIC, 4)) { fprintf(stderr, "Input file is not in RPM format!\n"); exit(1); } myread(6, buffer); /* Skip flags */ myread(64, buffer); 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_msg_and_die("%s", buffer); /* * 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, buffer); while (status < 2) { myread(1, buffer); 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_msg_and_die("write"); /* Now simply copy the GZIP archive into the output file */ while ((len = read(infile, buffer, BUFSIZ)) > 0) { if (write(outfile, buffer, len) < 0) perror_msg_and_die("write"); } if (len < 0) perror_msg_and_die("read"); return EXIT_SUCCESS; }