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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* write_header.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include "internal.h"
static void write_binary(char *dst, uint64_t value, int digits)
{
memset(dst, 0, digits);
while (digits > 0) {
((unsigned char *)dst)[digits - 1] = value & 0xFF;
--digits;
value >>= 8;
}
((unsigned char *)dst)[0] |= 0x80;
}
static void write_number(char *dst, uint64_t value, int digits)
{
uint64_t mask = 0;
char buffer[64];
int i;
for (i = 0; i < (digits - 1); ++i)
mask = (mask << 3) | 7;
if (value <= mask) {
sprintf(buffer, "%0*o ", digits - 1, (unsigned int)value);
memcpy(dst, buffer, digits);
} else if (value <= ((mask << 3) | 7)) {
sprintf(buffer, "%0*o", digits, (unsigned int)value);
memcpy(dst, buffer, digits);
} else {
write_binary(dst, value, digits);
}
}
static void write_number_signed(char *dst, int64_t value, int digits)
{
uint64_t neg;
if (value < 0) {
neg = -value;
write_binary(dst, ~neg + 1, digits);
} else {
write_number(dst, value, digits);
}
}
static int write_header(int fd, const struct stat *sb, const char *name,
const char *slink_target, int type)
{
int maj = 0, min = 0;
uint64_t size = 0;
tar_header_t hdr;
if (S_ISCHR(sb->st_mode) || S_ISBLK(sb->st_mode)) {
maj = major(sb->st_rdev);
min = minor(sb->st_rdev);
}
if (S_ISREG(sb->st_mode))
size = sb->st_size;
memset(&hdr, 0, sizeof(hdr));
strncpy(hdr.name, name, sizeof(hdr.name) - 1);
write_number(hdr.mode, sb->st_mode & ~S_IFMT, sizeof(hdr.mode));
write_number(hdr.uid, sb->st_uid, sizeof(hdr.uid));
write_number(hdr.gid, sb->st_gid, sizeof(hdr.gid));
write_number(hdr.size, size, sizeof(hdr.size));
write_number_signed(hdr.mtime, sb->st_mtime, sizeof(hdr.mtime));
hdr.typeflag = type;
if (slink_target != NULL)
memcpy(hdr.linkname, slink_target, sb->st_size);
memcpy(hdr.magic, TAR_MAGIC_OLD, sizeof(hdr.magic));
memcpy(hdr.version, TAR_VERSION_OLD, sizeof(hdr.version));
sprintf(hdr.uname, "%u", sb->st_uid);
sprintf(hdr.gname, "%u", sb->st_gid);
write_number(hdr.devmajor, maj, sizeof(hdr.devmajor));
write_number(hdr.devminor, min, sizeof(hdr.devminor));
update_checksum(&hdr);
return write_data("writing tar header record", fd, &hdr, sizeof(hdr));
}
static int write_gnu_header(int fd, const struct stat *orig,
const char *payload, size_t payload_len,
int type, const char *name)
{
struct stat sb;
sb = *orig;
sb.st_mode = S_IFREG | 0644;
sb.st_size = payload_len;
if (write_header(fd, &sb, name, NULL, type))
return -1;
if (write_data("writing GNU extension header",
fd, payload, payload_len)) {
return -1;
}
return padd_file(fd, payload_len, 512);
}
int write_tar_header(int fd, const struct stat *sb, const char *name,
const char *slink_target, unsigned int counter)
{
const char *reason;
char buffer[64];
int type;
if (!S_ISLNK(sb->st_mode))
slink_target = NULL;
if (S_ISLNK(sb->st_mode) && sb->st_size >= 100) {
sprintf(buffer, "gnu/target%u", counter);
if (write_gnu_header(fd, sb, slink_target, sb->st_size,
TAR_TYPE_GNU_SLINK, buffer))
return -1;
slink_target = NULL;
}
if (strlen(name) >= 100) {
sprintf(buffer, "gnu/name%u", counter);
if (write_gnu_header(fd, sb, name, strlen(name),
TAR_TYPE_GNU_PATH, buffer)) {
return -1;
}
sprintf(buffer, "gnu/data%u", counter);
name = buffer;
}
switch (sb->st_mode & S_IFMT) {
case S_IFCHR: type = TAR_TYPE_CHARDEV; break;
case S_IFBLK: type = TAR_TYPE_BLOCKDEV; break;
case S_IFLNK: type = TAR_TYPE_SLINK; break;
case S_IFREG: type = TAR_TYPE_FILE; break;
case S_IFDIR: type = TAR_TYPE_DIR; break;
case S_IFIFO: type = TAR_TYPE_FIFO; break;
case S_IFSOCK:
reason = "cannot pack socket";
goto out_skip;
default:
reason = "unknown type";
goto out_skip;
}
return write_header(fd, sb, name, slink_target, type);
out_skip:
fprintf(stderr, "WARNING: %s: %s\n", name, reason);
return 1;
}
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