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/* vi: set sw=4 ts=4: */
/*
* Copyright 2001 Glenn McGrath.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include "bb_archive.h"
#include "ar.h"
/* WARNING: Clobbers str[len], so fields must be read in reverse order! */
static unsigned read_num(char *str, int base, int len)
{
int err;
/* ar fields are fixed length text strings (padded with spaces).
* Ensure bb_strtou doesn't read past the field in case the full
* width is used. */
str[len] = 0;
/* This code works because
* on misformatted numbers bb_strtou returns all-ones */
err = bb_strtou(str, NULL, base);
if (err == -1)
bb_error_msg_and_die("invalid ar header");
return err;
}
char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
{
file_header_t *typed = archive_handle->file_header;
unsigned size;
union {
char raw[60];
struct ar_header formatted;
} ar;
#if ENABLE_FEATURE_AR_LONG_FILENAMES
static char *ar_long_names;
static unsigned ar_long_name_size;
#endif
/* dont use 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] = xread_char(archive_handle->src_fd);
archive_handle->offset++;
}
archive_handle->offset += 60;
if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n')
bb_error_msg_and_die("invalid ar header");
/*
* Note that the fields MUST be read in reverse order as
* read_num() clobbers the next byte after the field!
* Order is: name, date, uid, gid, mode, size, magic.
*/
typed->size = size = read_num(ar.formatted.size, 10,
sizeof(ar.formatted.size));
/* special filenames have '/' as the first character */
if (ar.formatted.name[0] == '/') {
if (ar.formatted.name[1] == ' ') {
/* This is the index of symbols in the file for compilers */
data_skip(archive_handle);
archive_handle->offset += size;
return get_header_ar(archive_handle); /* Return next header */
}
#if ENABLE_FEATURE_AR_LONG_FILENAMES
if (ar.formatted.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 = size;
free(ar_long_names);
ar_long_names = xzalloc(size + 1);
xread(archive_handle->src_fd, ar_long_names, size);
archive_handle->offset += size;
/* Return next header */
return get_header_ar(archive_handle);
}
#else
bb_error_msg_and_die("long filenames not supported");
#endif
}
/* Only size is always present, the rest may be missing in
* long filename pseudo file. Thus we decode the rest
* after dealing with long filename pseudo file.
*/
typed->mode = read_num(ar.formatted.mode, 8, sizeof(ar.formatted.mode));
typed->gid = read_num(ar.formatted.gid, 10, sizeof(ar.formatted.gid));
typed->uid = read_num(ar.formatted.uid, 10, sizeof(ar.formatted.uid));
typed->mtime = read_num(ar.formatted.date, 10, sizeof(ar.formatted.date));
#if ENABLE_FEATURE_AR_LONG_FILENAMES
if (ar.formatted.name[0] == '/') {
unsigned long_offset;
/* The number after the '/' indicates the offset in the ar data section
* (saved in ar_long_names) that contains the real filename */
long_offset = read_num(&ar.formatted.name[1], 10,
sizeof(ar.formatted.name) - 1);
if (long_offset >= ar_long_name_size) {
bb_error_msg_and_die("can't resolve long filename");
}
typed->name = xstrdup(ar_long_names + long_offset);
} else
#endif
{
/* short filenames */
typed->name = xstrndup(ar.formatted.name, 16);
}
typed->name[strcspn(typed->name, " /")] = '\0';
if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
archive_handle->action_header(typed);
#if ENABLE_DPKG || ENABLE_DPKG_DEB
if (archive_handle->dpkg__sub_archive) {
while (archive_handle->dpkg__action_data_subarchive(archive_handle->dpkg__sub_archive) == EXIT_SUCCESS)
continue;
} else
#endif
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;
}
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