busybox/archival/libunarchive/get_header_ar.c

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/* vi: set sw=4 ts=4: */
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/* Copyright 2001 Glenn McGrath.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
#include "libbb.h"
#include "unarchive.h"
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char get_header_ar(archive_handle_t *archive_handle)
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{
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file_header_t *typed = archive_handle->file_header;
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union {
char raw[60];
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struct {
char name[16];
char date[12];
char uid[6];
char gid[6];
char mode[8];
char size[10];
char magic[2];
} formatted;
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} ar;
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#ifdef CONFIG_FEATURE_AR_LONG_FILENAMES
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static char *ar_long_names;
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static unsigned int ar_long_name_size;
#endif
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/* dont use xread as we want to handle the error ourself */
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if (read(archive_handle->src_fd, ar.raw, 60) != 60) {
/* End Of File */
return EXIT_FAILURE;
}
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/* ar header starts on an even byte (2 byte aligned)
* '\n' is used for padding
*/
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if (ar.raw[0] == '\n') {
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/* fix up the header, we started reading 1 byte too early */
memmove(ar.raw, &ar.raw[1], 59);
ar.raw[59] = xread_char(archive_handle->src_fd);
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archive_handle->offset++;
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}
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archive_handle->offset += 60;
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/* align the headers based on the header magic */
if ((ar.formatted.magic[0] != '`') || (ar.formatted.magic[1] != '\n')) {
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bb_error_msg_and_die("invalid ar header");
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}
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typed->mode = xstrtoul(ar.formatted.mode, 8);
typed->mtime = xatou(ar.formatted.date);
typed->uid = xatou(ar.formatted.uid);
typed->gid = xatou(ar.formatted.gid);
typed->size = xatoul(ar.formatted.size);
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/* long filenames have '/' as the first character */
if (ar.formatted.name[0] == '/') {
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#ifdef CONFIG_FEATURE_AR_LONG_FILENAMES
if (ar.formatted.name[1] == '/') {
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/* 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 */
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ar_long_name_size = typed->size;
ar_long_names = xmalloc(ar_long_name_size);
xread(archive_handle->src_fd, ar_long_names, ar_long_name_size);
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archive_handle->offset += ar_long_name_size;
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/* 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.formatted.name[1] == ' ') {
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/* This is the index of symbols in the file for compilers */
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data_skip(archive_handle);
archive_handle->offset += typed->size;
return get_header_ar(archive_handle); /* Return next header */
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} 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.formatted.name[1]);
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if (long_offset >= ar_long_name_size) {
bb_error_msg_and_die("can't resolve long filename");
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}
typed->name = xstrdup(ar_long_names + long_offset);
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}
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#else
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bb_error_msg_and_die("long filenames not supported");
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#endif
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} else {
/* short filenames */
typed->name = xstrndup(ar.formatted.name, 16);
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}
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typed->name[strcspn(typed->name, " /")] = '\0';
if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
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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);
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}
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);
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return EXIT_SUCCESS;
}