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Diffstat (limited to 'tar/read_header.c')
-rw-r--r--tar/read_header.c415
1 files changed, 0 insertions, 415 deletions
diff --git a/tar/read_header.c b/tar/read_header.c
deleted file mode 100644
index bdb2d20..0000000
--- a/tar/read_header.c
+++ /dev/null
@@ -1,415 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-#include "util.h"
-#include "tar.h"
-
-#include <sys/sysmacros.h>
-#include <string.h>
-#include <stdlib.h>
-#include <ctype.h>
-#include <stdio.h>
-
-enum {
- PAX_SIZE = 0x001,
- PAX_UID = 0x002,
- PAX_GID = 0x004,
- PAX_DEV_MAJ = 0x008,
- PAX_DEV_MIN = 0x010,
- PAX_NAME = 0x020,
- PAX_SLINK_TARGET = 0x040,
- PAX_ATIME = 0x080,
- PAX_MTIME = 0x100,
- PAX_CTIME = 0x200,
-};
-
-static int read_octal(const char *str, int digits, uint64_t *out)
-{
- uint64_t result = 0;
-
- while (digits > 0 && *str >= '0' && *str <= '7') {
- if (result > 0x1FFFFFFFFFFFFFFFUL) {
- fputs("numeric overflow parsing tar header\n", stderr);
- return -1;
- }
-
- result = (result << 3) | (*(str++) - '0');
- --digits;
- }
-
- *out = result;
- return 0;
-}
-
-static int read_binary(const char *str, int digits, uint64_t *out)
-{
- uint64_t x, result = 0;
-
- while (digits > 0) {
- if (result > 0x00FFFFFFFFFFFFFFUL) {
- fputs("numeric overflow parsing tar header\n", stderr);
- return -1;
- }
-
- x = *((const unsigned char *)str++);
- result = (result << 8) | x;
- --digits;
- }
-
- *out = result;
- return 0;
-}
-
-static int read_number(const char *str, int digits, uint64_t *out)
-{
- if (*((unsigned char *)str) & 0x80) {
- if (read_binary(str, digits, out))
- return -1;
- *out &= 0x7FFFFFFFFFFFFFFF;
- return 0;
- }
-
- return read_octal(str, digits, out);
-}
-
-static bool is_zero_block(const tar_header_t *hdr)
-{
- const unsigned char *ptr = (const unsigned char *)hdr;
-
- return ptr[0] == '\0' && memcmp(ptr, ptr + 1, sizeof(*hdr) - 1) == 0;
-}
-
-static bool is_checksum_valid(const tar_header_t *hdr)
-{
- unsigned int chksum = 0;
- tar_header_t copy;
- uint64_t ref;
- size_t i;
-
- if (read_octal(hdr->chksum, sizeof(hdr->chksum), &ref))
- return false;
-
- memcpy(&copy, hdr, sizeof(*hdr));
- memset(copy.chksum, ' ', sizeof(copy.chksum));
-
- for (i = 0; i < sizeof(copy); ++i)
- chksum += ((unsigned char *)&copy)[i];
-
- return chksum == ref;
-}
-
-static bool is_magic_valid(const tar_header_t *hdr)
-{
- if (memcmp(hdr->magic, TAR_MAGIC, sizeof(hdr->magic)) != 0)
- return false;
-
- if (memcmp(hdr->version, TAR_VERSION, sizeof(hdr->version)) != 0)
- return false;
-
- return true;
-}
-
-static int pax_read_decimal(const char *str, uint64_t *out)
-{
- uint64_t result = 0;
-
- while (*str >= '0' && *str <= '9') {
- if (result > 0xFFFFFFFFFFFFFFFFUL / 10) {
- fputs("numeric overflow parsing pax header\n", stderr);
- return -1;
- }
-
- result = (result * 10) + (*(str++) - '0');
- }
-
- *out = result;
- return 0;
-}
-
-static int read_pax_header(int fd, uint64_t entsize, unsigned int *set_by_pax,
- tar_header_decoded_t *out)
-{
- char *buffer, *line;
- uint64_t field;
- ssize_t ret;
- uint64_t i;
-
- buffer = malloc(entsize + 1);
- if (buffer == NULL)
- goto fail_errno;
-
- ret = read_retry(fd, buffer, entsize);
- if (ret < 0)
- goto fail_errno;
- if ((size_t)ret < entsize)
- goto fail_eof;
-
- if (skip_padding(fd, entsize))
- goto fail;
-
- buffer[entsize] = '\0';
-
- for (i = 0; i < entsize; ++i) {
- while (i < entsize && isspace(buffer[i]))
- ++i;
- while (i < entsize && isdigit(buffer[i]))
- ++i;
- while (i < entsize && isspace(buffer[i]))
- ++i;
- if (i >= entsize)
- break;
-
- line = buffer + i;
-
- while (i < entsize && buffer[i] != '\n')
- ++i;
-
- buffer[i] = '\0';
-
- if (!strncmp(line, "uid=", 4)) {
- pax_read_decimal(line + 4, &field);
- out->sb.st_uid = field;
- *set_by_pax |= PAX_UID;
- } else if (!strncmp(line, "gid=", 4)) {
- pax_read_decimal(line + 4, &field);
- out->sb.st_gid = field;
- *set_by_pax |= PAX_GID;
- } else if (!strncmp(line, "path=", 5)) {
- free(out->name);
- out->name = strdup(line + 5);
- if (out->name == NULL)
- goto fail_errno;
- *set_by_pax |= PAX_NAME;
- } else if (!strncmp(line, "size=", 5)) {
- pax_read_decimal(line + 5, &field);
- out->sb.st_size = field;
- *set_by_pax |= PAX_SIZE;
- } else if (!strncmp(line, "linkpath=", 9)) {
- free(out->link_target);
- out->link_target = strdup(line + 9);
- if (out->link_target == NULL)
- goto fail_errno;
- *set_by_pax |= PAX_SLINK_TARGET;
- } else if (!strncmp(line, "atime=", 6)) {
- pax_read_decimal(line + 6, &field);
- out->sb.st_atime = field;
- *set_by_pax |= PAX_ATIME;
- } else if (!strncmp(line, "mtime=", 6)) {
- pax_read_decimal(line + 6, &field);
- out->sb.st_mtime = field;
- *set_by_pax |= PAX_MTIME;
- } else if (!strncmp(line, "ctime=", 6)) {
- pax_read_decimal(line + 6, &field);
- out->sb.st_ctime = field;
- *set_by_pax |= PAX_CTIME;
- }
- }
-
- free(buffer);
- return 0;
-fail_errno:
- perror("reading pax header");
- goto fail;
-fail_eof:
- fputs("reading pax header: unexpected end of file\n", stderr);
- goto fail;
-fail:
- free(buffer);
- return -1;
-}
-
-static int decode_header(const tar_header_t *hdr, unsigned int set_by_pax,
- tar_header_decoded_t *out)
-{
- uint64_t field;
- size_t count;
-
- if (!(set_by_pax & PAX_NAME)) {
- if (hdr->prefix[0] == '\0') {
- count = strlen(hdr->name) + 1;
- count += strlen(hdr->prefix) + 1;
-
- out->name = malloc(count);
-
- if (out->name != NULL) {
- sprintf(out->name, "%s/%s",
- hdr->prefix, hdr->name);
- }
- } else {
- out->name = strdup(hdr->name);
- }
-
- if (out->name == NULL) {
- perror("decoding filename");
- return -1;
- }
- }
-
- if (!(set_by_pax & PAX_SIZE)) {
- if (read_number(hdr->size, sizeof(hdr->size), &field))
- return -1;
- out->sb.st_size = field;
- }
-
- if (!(set_by_pax & PAX_UID)) {
- if (read_number(hdr->uid, sizeof(hdr->uid), &field))
- return -1;
- out->sb.st_uid = field;
- }
-
- if (!(set_by_pax & PAX_GID)) {
- if (read_number(hdr->gid, sizeof(hdr->gid), &field))
- return -1;
- out->sb.st_gid = field;
- }
-
- if (!(set_by_pax & PAX_DEV_MAJ)) {
- if (read_number(hdr->devmajor, sizeof(hdr->devmajor), &field))
- return -1;
-
- out->sb.st_rdev = makedev(field, minor(out->sb.st_rdev));
- }
-
- if (!(set_by_pax & PAX_DEV_MIN)) {
- if (read_number(hdr->devminor, sizeof(hdr->devminor), &field))
- return -1;
-
- out->sb.st_rdev = makedev(major(out->sb.st_rdev), field);
- }
-
- if (!(set_by_pax & PAX_MTIME)) {
- if (read_number(hdr->mtime, sizeof(hdr->mtime), &field))
- return -1;
- out->sb.st_mtime = field;
- }
-
- if (!(set_by_pax & PAX_ATIME))
- out->sb.st_atime = out->sb.st_mtime;
-
- if (!(set_by_pax & PAX_CTIME))
- out->sb.st_ctime = out->sb.st_mtime;
-
- if (read_octal(hdr->mode, sizeof(hdr->mode), &field))
- return -1;
-
- out->sb.st_mode = field & 07777;
-
- if (hdr->typeflag == TAR_TYPE_LINK ||
- hdr->typeflag == TAR_TYPE_SLINK) {
- if (!(set_by_pax & PAX_SLINK_TARGET)) {
- out->link_target = strdup(hdr->linkname);
- if (out->link_target == NULL) {
- perror("decoding symlink target");
- return -1;
- }
- }
- }
-
- out->unknown_record = false;
-
- switch (hdr->typeflag) {
- case '\0':
- case TAR_TYPE_FILE:
- out->sb.st_mode |= S_IFREG;
- break;
- case TAR_TYPE_LINK:
- /* XXX: hard links are not support yet */
- out->sb.st_mode = S_IFLNK | 0777;
- break;
- case TAR_TYPE_SLINK:
- out->sb.st_mode = S_IFLNK | 0777;
- break;
- case TAR_TYPE_CHARDEV:
- out->sb.st_mode |= S_IFCHR;
- break;
- case TAR_TYPE_BLOCKDEV:
- out->sb.st_mode |= S_IFBLK;
- break;
- case TAR_TYPE_DIR:
- out->sb.st_mode |= S_IFDIR;
- break;
- case TAR_TYPE_FIFO:
- out->sb.st_mode |= S_IFIFO;
- break;
- default:
- out->unknown_record = true;
- break;
- }
-
- return 0;
-}
-
-int read_header(int fd, tar_header_decoded_t *out)
-{
- unsigned int set_by_pax = 0;
- bool prev_was_zero = false;
- uint64_t pax_size;
- tar_header_t hdr;
- int ret;
-
- memset(out, 0, sizeof(*out));
-
- for (;;) {
- ret = read_retry(fd, &hdr, sizeof(hdr));
- if (ret == 0)
- goto out_eof;
- if (ret < 0)
- goto fail_errno;
- if (ret < (int)sizeof(hdr))
- goto fail_eof;
-
- if (is_zero_block(&hdr)) {
- if (prev_was_zero)
- goto out_eof;
- prev_was_zero = true;
- continue;
- }
-
- prev_was_zero = false;
-
- if (!is_magic_valid(&hdr))
- goto fail_magic;
-
- if (!is_checksum_valid(&hdr))
- goto fail_chksum;
-
- if (hdr.typeflag == TAR_TYPE_PAX) {
- clear_header(out);
- if (read_number(hdr.size, sizeof(hdr.size), &pax_size))
- return -1;
- set_by_pax = 0;
- if (read_pax_header(fd, pax_size, &set_by_pax, out))
- return -1;
- continue;
- }
- break;
- }
-
- if (decode_header(&hdr, set_by_pax, out))
- goto fail;
-
- return 0;
-out_eof:
- clear_header(out);
- return 1;
-fail_errno:
- perror("reading tar header");
- goto fail;
-fail_eof:
- fputs("reading tar header: unexpected end of file\n", stderr);
- goto fail;
-fail_magic:
- fputs("input is not a ustar tar archive!\n", stderr);
- goto fail;
-fail_chksum:
- fputs("invalid tar header checksum!\n", stderr);
- goto fail;
-fail:
- clear_header(out);
- return -1;
-}
-
-void clear_header(tar_header_decoded_t *hdr)
-{
- free(hdr->name);
- free(hdr->link_target);
- memset(hdr, 0, sizeof(*hdr));
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-29 00:01:31 +0000