summaryrefslogtreecommitdiffstats
path: root/libtar/block.c
diff options
context:
space:
mode:
Diffstat (limited to 'libtar/block.c')
-rw-r--r--libtar/block.c496
1 files changed, 496 insertions, 0 deletions
diff --git a/libtar/block.c b/libtar/block.c
new file mode 100644
index 000000000..6ed9e6000
--- /dev/null
+++ b/libtar/block.c
@@ -0,0 +1,496 @@
+/*
+** Copyright 1998-2003 University of Illinois Board of Trustees
+** Copyright 1998-2003 Mark D. Roth
+** All rights reserved.
+**
+** block.c - libtar code to handle tar archive header blocks
+**
+** Mark D. Roth <roth@uiuc.edu>
+** Campus Information Technologies and Educational Services
+** University of Illinois at Urbana-Champaign
+*/
+
+#include <internal.h>
+#include <stdio.h>
+#include <errno.h>
+
+#ifdef STDC_HEADERS
+# include <string.h>
+# include <stdlib.h>
+#endif
+
+#define BIT_ISSET(bitmask, bit) ((bitmask) & (bit))
+
+// Used to identify selinux_context in extended ('x')
+// metadata. From RedHat implementation.
+#define SELINUX_TAG "RHT.security.selinux="
+#define SELINUX_TAG_LEN 21
+
+/* read a header block */
+int
+th_read_internal(TAR *t)
+{
+ int i;
+ int num_zero_blocks = 0;
+
+#ifdef DEBUG
+ printf("==> th_read_internal(TAR=\"%s\")\n", t->pathname);
+#endif
+
+ while ((i = tar_block_read(t, &(t->th_buf))) == T_BLOCKSIZE)
+ {
+ /* two all-zero blocks mark EOF */
+ if (t->th_buf.name[0] == '\0')
+ {
+ num_zero_blocks++;
+ if (!BIT_ISSET(t->options, TAR_IGNORE_EOT)
+ && num_zero_blocks >= 2)
+ return 0; /* EOF */
+ else
+ continue;
+ }
+
+ /* verify magic and version */
+ if (BIT_ISSET(t->options, TAR_CHECK_MAGIC)
+ && strncmp(t->th_buf.magic, TMAGIC, TMAGLEN - 1) != 0)
+ {
+#ifdef DEBUG
+ puts("!!! unknown magic value in tar header");
+#endif
+ return -2;
+ }
+
+ if (BIT_ISSET(t->options, TAR_CHECK_VERSION)
+ && strncmp(t->th_buf.version, TVERSION, TVERSLEN) != 0)
+ {
+#ifdef DEBUG
+ puts("!!! unknown version value in tar header");
+#endif
+ return -2;
+ }
+
+ /* check chksum */
+ if (!BIT_ISSET(t->options, TAR_IGNORE_CRC)
+ && !th_crc_ok(t))
+ {
+#ifdef DEBUG
+ puts("!!! tar header checksum error");
+#endif
+ return -2;
+ }
+
+ break;
+ }
+
+#ifdef DEBUG
+ printf("<== th_read_internal(): returning %d\n", i);
+#endif
+ return i;
+}
+
+
+/* wrapper function for th_read_internal() to handle GNU extensions */
+int
+th_read(TAR *t)
+{
+ int i, j;
+ size_t sz;
+ char *ptr;
+
+#ifdef DEBUG
+ printf("==> th_read(t=0x%lx)\n", t);
+#endif
+
+ if (t->th_buf.gnu_longname != NULL)
+ free(t->th_buf.gnu_longname);
+ if (t->th_buf.gnu_longlink != NULL)
+ free(t->th_buf.gnu_longlink);
+#ifdef HAVE_SELINUX
+ if (t->th_buf.selinux_context != NULL)
+ free(t->th_buf.selinux_context);
+#endif
+
+ memset(&(t->th_buf), 0, sizeof(struct tar_header));
+
+ i = th_read_internal(t);
+ if (i == 0)
+ return 1;
+ else if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* check for GNU long link extention */
+ if (TH_ISLONGLINK(t))
+ {
+ sz = th_get_size(t);
+ j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0);
+#ifdef DEBUG
+ printf(" th_read(): GNU long linkname detected "
+ "(%ld bytes, %d blocks)\n", sz, j);
+#endif
+ t->th_buf.gnu_longlink = (char *)malloc(j * T_BLOCKSIZE);
+ if (t->th_buf.gnu_longlink == NULL)
+ return -1;
+
+ for (ptr = t->th_buf.gnu_longlink; j > 0;
+ j--, ptr += T_BLOCKSIZE)
+ {
+#ifdef DEBUG
+ printf(" th_read(): reading long linkname "
+ "(%d blocks left, ptr == %ld)\n", j, ptr);
+#endif
+ i = tar_block_read(t, ptr);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+#ifdef DEBUG
+ printf(" th_read(): read block == \"%s\"\n", ptr);
+#endif
+ }
+#ifdef DEBUG
+ printf(" th_read(): t->th_buf.gnu_longlink == \"%s\"\n",
+ t->th_buf.gnu_longlink);
+#endif
+
+ i = th_read_internal(t);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+ }
+
+ /* check for GNU long name extention */
+ if (TH_ISLONGNAME(t))
+ {
+ sz = th_get_size(t);
+ j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0);
+#ifdef DEBUG
+ printf(" th_read(): GNU long filename detected "
+ "(%ld bytes, %d blocks)\n", sz, j);
+#endif
+ t->th_buf.gnu_longname = (char *)malloc(j * T_BLOCKSIZE);
+ if (t->th_buf.gnu_longname == NULL)
+ return -1;
+
+ for (ptr = t->th_buf.gnu_longname; j > 0;
+ j--, ptr += T_BLOCKSIZE)
+ {
+#ifdef DEBUG
+ printf(" th_read(): reading long filename "
+ "(%d blocks left, ptr == %ld)\n", j, ptr);
+#endif
+ i = tar_block_read(t, ptr);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+#ifdef DEBUG
+ printf(" th_read(): read block == \"%s\"\n", ptr);
+#endif
+ }
+#ifdef DEBUG
+ printf(" th_read(): t->th_buf.gnu_longname == \"%s\"\n",
+ t->th_buf.gnu_longname);
+#endif
+
+ i = th_read_internal(t);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+ }
+
+#ifdef HAVE_SELINUX
+ if(TH_ISEXTHEADER(t))
+ {
+ sz = th_get_size(t);
+
+ if(sz >= T_BLOCKSIZE) // Not supported
+ {
+#ifdef DEBUG
+ printf(" th_read(): Extended header is too long!\n");
+#endif
+ }
+ else
+ {
+ char buf[T_BLOCKSIZE];
+ i = tar_block_read(t, buf);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ // To be sure
+ buf[T_BLOCKSIZE-1] = 0;
+
+ int len = strlen(buf);
+ char *start = strstr(buf, SELINUX_TAG);
+ if(start && start+SELINUX_TAG_LEN < buf+len)
+ {
+ start += SELINUX_TAG_LEN;
+ char *end = strchr(start, '\n');
+ if(end)
+ {
+ t->th_buf.selinux_context = strndup(start, end-start);
+#ifdef DEBUG
+ printf(" th_read(): SELinux context xattr detected: %s\n", t->th_buf.selinux_context);
+#endif
+ }
+ }
+ }
+
+ i = th_read_internal(t);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+ }
+#endif
+
+#if 0
+ /*
+ ** work-around for old archive files with broken typeflag fields
+ ** NOTE: I fixed this in the TH_IS*() macros instead
+ */
+
+ /*
+ ** (directories are signified with a trailing '/')
+ */
+ if (t->th_buf.typeflag == AREGTYPE
+ && t->th_buf.name[strlen(t->th_buf.name) - 1] == '/')
+ t->th_buf.typeflag = DIRTYPE;
+
+ /*
+ ** fallback to using mode bits
+ */
+ if (t->th_buf.typeflag == AREGTYPE)
+ {
+ mode = (mode_t)oct_to_int(t->th_buf.mode);
+
+ if (S_ISREG(mode))
+ t->th_buf.typeflag = REGTYPE;
+ else if (S_ISDIR(mode))
+ t->th_buf.typeflag = DIRTYPE;
+ else if (S_ISFIFO(mode))
+ t->th_buf.typeflag = FIFOTYPE;
+ else if (S_ISCHR(mode))
+ t->th_buf.typeflag = CHRTYPE;
+ else if (S_ISBLK(mode))
+ t->th_buf.typeflag = BLKTYPE;
+ else if (S_ISLNK(mode))
+ t->th_buf.typeflag = SYMTYPE;
+ }
+#endif
+
+ return 0;
+}
+
+
+/* write a header block */
+int
+th_write(TAR *t)
+{
+ int i, j;
+ char type2;
+ size_t sz, sz2;
+ char *ptr;
+ char buf[T_BLOCKSIZE];
+
+#ifdef DEBUG
+ printf("==> th_write(TAR=\"%s\")\n", t->pathname);
+ th_print(t);
+#endif
+
+ if ((t->options & TAR_GNU) && t->th_buf.gnu_longlink != NULL)
+ {
+#ifdef DEBUG
+ printf("th_write(): using gnu_longlink (\"%s\")\n",
+ t->th_buf.gnu_longlink);
+#endif
+ /* save old size and type */
+ type2 = t->th_buf.typeflag;
+ sz2 = th_get_size(t);
+
+ /* write out initial header block with fake size and type */
+ t->th_buf.typeflag = GNU_LONGLINK_TYPE;
+ sz = strlen(t->th_buf.gnu_longlink);
+ th_set_size(t, sz);
+ th_finish(t);
+ i = tar_block_write(t, &(t->th_buf));
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* write out extra blocks containing long name */
+ for (j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0),
+ ptr = t->th_buf.gnu_longlink; j > 1;
+ j--, ptr += T_BLOCKSIZE)
+ {
+ i = tar_block_write(t, ptr);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+ }
+ memset(buf, 0, T_BLOCKSIZE);
+ strncpy(buf, ptr, T_BLOCKSIZE);
+ i = tar_block_write(t, &buf);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* reset type and size to original values */
+ t->th_buf.typeflag = type2;
+ th_set_size(t, sz2);
+ }
+
+ if ((t->options & TAR_GNU) && t->th_buf.gnu_longname != NULL)
+ {
+#ifdef DEBUG
+ printf("th_write(): using gnu_longname (\"%s\")\n",
+ t->th_buf.gnu_longname);
+#endif
+ /* save old size and type */
+ type2 = t->th_buf.typeflag;
+ sz2 = th_get_size(t);
+
+ /* write out initial header block with fake size and type */
+ t->th_buf.typeflag = GNU_LONGNAME_TYPE;
+ sz = strlen(t->th_buf.gnu_longname);
+ th_set_size(t, sz);
+ th_finish(t);
+ i = tar_block_write(t, &(t->th_buf));
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* write out extra blocks containing long name */
+ for (j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0),
+ ptr = t->th_buf.gnu_longname; j > 1;
+ j--, ptr += T_BLOCKSIZE)
+ {
+ i = tar_block_write(t, ptr);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+ }
+ memset(buf, 0, T_BLOCKSIZE);
+ strncpy(buf, ptr, T_BLOCKSIZE);
+ i = tar_block_write(t, &buf);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* reset type and size to original values */
+ t->th_buf.typeflag = type2;
+ th_set_size(t, sz2);
+ }
+
+#ifdef HAVE_SELINUX
+ if((t->options & TAR_STORE_SELINUX) && t->th_buf.selinux_context != NULL)
+ {
+#ifdef DEBUG
+ printf("th_write(): using selinux_context (\"%s\")\n",
+ t->th_buf.selinux_context);
+#endif
+ /* save old size and type */
+ type2 = t->th_buf.typeflag;
+ sz2 = th_get_size(t);
+
+ /* write out initial header block with fake size and type */
+ t->th_buf.typeflag = TH_EXT_TYPE;
+
+ /* setup size - EXT header has format "*size of this whole tag as ascii numbers* *space* *content* *newline* */
+ // size newline
+ sz = SELINUX_TAG_LEN + strlen(t->th_buf.selinux_context) + 3 + 1;
+
+ if(sz >= 100) // another ascci digit for size
+ ++sz;
+
+ if(sz >= T_BLOCKSIZE) // impossible
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ th_set_size(t, sz);
+ th_finish(t);
+ i = tar_block_write(t, &(t->th_buf));
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ memset(buf, 0, T_BLOCKSIZE);
+ snprintf(buf, T_BLOCKSIZE, "%d "SELINUX_TAG"%s\n", sz, t->th_buf.selinux_context);
+ i = tar_block_write(t, &buf);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* reset type and size to original values */
+ t->th_buf.typeflag = type2;
+ th_set_size(t, sz2);
+ }
+#endif
+
+ th_finish(t);
+
+#ifdef DEBUG
+ /* print tar header */
+ th_print(t);
+#endif
+
+ i = tar_block_write(t, &(t->th_buf));
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+#ifdef DEBUG
+ puts("th_write(): returning 0");
+#endif
+ return 0;
+}
+
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-31 11:15:31 +0100