busybox/archival/libunarchive/get_header_ar.c

117 lines
3.7 KiB
C

/* vi: set sw=4 ts=4: */
/* Copyright 2001 Glenn McGrath.
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "unarchive.h"
#include "libbb.h"
char get_header_ar(archive_handle_t *archive_handle)
{
file_header_t *typed = archive_handle->file_header;
union {
char raw[60];
struct {
char name[16];
char date[12];
char uid[6];
char gid[6];
char mode[8];
char size[10];
char magic[2];
} formated;
} ar;
#ifdef CONFIG_FEATURE_AR_LONG_FILENAMES
static char *ar_long_names;
static unsigned int ar_long_name_size;
#endif
/* dont use bb_xread as we want to handle the error ourself */
if (read(archive_handle->src_fd, ar.raw, 60) != 60) {
/* End Of File */
return(EXIT_FAILURE);
}
/* ar header starts on an even byte (2 byte aligned)
* '\n' is used for padding
*/
if (ar.raw[0] == '\n') {
/* fix up the header, we started reading 1 byte too early */
memmove(ar.raw, &ar.raw[1], 59);
ar.raw[59] = bb_xread_char(archive_handle->src_fd);
archive_handle->offset++;
}
archive_handle->offset += 60;
/* align the headers based on the header magic */
if ((ar.formated.magic[0] != '`') || (ar.formated.magic[1] != '\n')) {
bb_error_msg_and_die("Invalid ar header");
}
typed->mode = strtol(ar.formated.mode, NULL, 8);
typed->mtime = atoi(ar.formated.date);
typed->uid = atoi(ar.formated.uid);
typed->gid = atoi(ar.formated.gid);
typed->size = atoi(ar.formated.size);
/* long filenames have '/' as the first character */
if (ar.formated.name[0] == '/') {
#ifdef CONFIG_FEATURE_AR_LONG_FILENAMES
if (ar.formated.name[1] == '/') {
/* If the second char is a '/' then this entries data section
* stores long filename for multiple entries, they are stored
* in static variable long_names for use in future entries */
ar_long_name_size = typed->size;
ar_long_names = xmalloc(ar_long_name_size);
bb_xread_all(archive_handle->src_fd, ar_long_names, ar_long_name_size);
archive_handle->offset += ar_long_name_size;
/* This ar entries data section only contained filenames for other records
* they are stored in the static ar_long_names for future reference */
return (get_header_ar(archive_handle)); /* Return next header */
} else if (ar.formated.name[1] == ' ') {
/* This is the index of symbols in the file for compilers */
data_skip(archive_handle);
archive_handle->offset += typed->size;
return (get_header_ar(archive_handle)); /* Return next header */
} else {
/* The number after the '/' indicates the offset in the ar data section
(saved in variable long_name) that conatains the real filename */
const unsigned int long_offset = atoi(&ar.formated.name[1]);
if (long_offset >= ar_long_name_size) {
bb_error_msg_and_die("Cant resolve long filename");
}
typed->name = bb_xstrdup(ar_long_names + long_offset);
}
#else
bb_error_msg_and_die("long filenames not supported");
#endif
} else {
/* short filenames */
typed->name = bb_xstrndup(ar.formated.name, 16);
}
typed->name[strcspn(typed->name, " /")] = '\0';
if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
archive_handle->action_header(typed);
if (archive_handle->sub_archive) {
while (archive_handle->action_data_subarchive(archive_handle->sub_archive) == EXIT_SUCCESS);
} else {
archive_handle->action_data(archive_handle);
}
} else {
data_skip(archive_handle);
}
archive_handle->offset += typed->size;
/* Set the file pointer to the correct spot, we may have been reading a compressed file */
lseek(archive_handle->src_fd, archive_handle->offset, SEEK_SET);
return(EXIT_SUCCESS);
}