svn commit: r201170 - head/lib/libarchive
Tim Kientzle
kientzle at FreeBSD.org
Tue Dec 29 06:34:23 UTC 2009
Author: kientzle
Date: Tue Dec 29 06:34:23 2009
New Revision: 201170
URL: http://svn.freebsd.org/changeset/base/201170
Log:
Essentially eliminate problems with false hardlinks in POSIX cpio
archives by generating synthetic ino values and mapping values
from disk into the new values.
Modified:
head/lib/libarchive/archive_write_set_format_cpio.c
Modified: head/lib/libarchive/archive_write_set_format_cpio.c
==============================================================================
--- head/lib/libarchive/archive_write_set_format_cpio.c Tue Dec 29 06:27:19 2009 (r201169)
+++ head/lib/libarchive/archive_write_set_format_cpio.c Tue Dec 29 06:34:23 2009 (r201170)
@@ -54,6 +54,12 @@ static int64_t format_octal_recursive(in
struct cpio {
uint64_t entry_bytes_remaining;
+
+ int64_t ino_next;
+
+ struct { int64_t old; int new;} *ino_list;
+ size_t ino_list_size;
+ size_t ino_list_next;
};
struct cpio_header {
@@ -103,35 +109,102 @@ archive_write_set_format_cpio(struct arc
return (ARCHIVE_OK);
}
+/*
+ * Ino values are as long as 64 bits on some systems; cpio format
+ * only allows 18 bits and relies on the ino values to identify hardlinked
+ * files. So, we can't merely "hash" the ino numbers since collisions
+ * would corrupt the archive. Instead, we generate synthetic ino values
+ * to store in the archive and maintain a map of original ino values to
+ * synthetic ones so we can preserve hardlink information.
+ *
+ * TODO: Make this more efficient. It's not as bad as it looks (most
+ * files don't have any hardlinks and we don't do any work here for those),
+ * but it wouldn't be hard to do better.
+ *
+ * TODO: Work with dev/ino pairs here instead of just ino values.
+ */
+static int
+synthesize_ino_value(struct cpio *cpio, struct archive_entry *entry)
+{
+ int64_t ino = archive_entry_ino64(entry);
+ int ino_new;
+ size_t i;
+
+ /*
+ * If no index number was given, don't assign one. In
+ * particular, this handles the end-of-archive marker
+ * correctly by giving it a zero index value. (This is also
+ * why we start our synthetic index numbers with one below.)
+ */
+ if (ino == 0)
+ return (0);
+
+ /* Don't store a mapping if we don't need to. */
+ if (archive_entry_nlink(entry) < 2) {
+ return ++cpio->ino_next;
+ }
+
+ /* Look up old ino; if we have it, this is a hardlink
+ * and we reuse the same value. */
+ for (i = 0; i < cpio->ino_list_next; ++i) {
+ if (cpio->ino_list[i].old == ino)
+ return (cpio->ino_list[i].new);
+ }
+
+ /* Assign a new index number. */
+ ino_new = ++cpio->ino_next;
+
+ /* Ensure space for the new mapping. */
+ if (cpio->ino_list_size <= cpio->ino_list_next) {
+ size_t newsize = cpio->ino_list_size < 512
+ ? 512 : cpio->ino_list_size * 2;
+ void *newlist = realloc(cpio->ino_list,
+ sizeof(cpio->ino_list[0]) * newsize);
+ if (newlist == NULL)
+ return (-1);
+
+ cpio->ino_list_size = newsize;
+ cpio->ino_list = newlist;
+ }
+
+ /* Record and return the new value. */
+ cpio->ino_list[cpio->ino_list_next].old = ino;
+ cpio->ino_list[cpio->ino_list_next].new = ino_new;
+ ++cpio->ino_list_next;
+ return (ino_new);
+}
+
static int
archive_write_cpio_header(struct archive_write *a, struct archive_entry *entry)
{
struct cpio *cpio;
const char *p, *path;
- int pathlength, ret;
+ int pathlength, ret, ret2;
+ int64_t ino;
struct cpio_header h;
cpio = (struct cpio *)a->format_data;
- ret = 0;
+ ret2 = ARCHIVE_OK;
path = archive_entry_pathname(entry);
- pathlength = strlen(path) + 1; /* Include trailing null. */
+ pathlength = (int)strlen(path) + 1; /* Include trailing null. */
memset(&h, 0, sizeof(h));
format_octal(070707, &h.c_magic, sizeof(h.c_magic));
format_octal(archive_entry_dev(entry), &h.c_dev, sizeof(h.c_dev));
- /*
- * TODO: Generate artificial inode numbers rather than just
- * re-using the ones off the disk. That way, the 18-bit c_ino
- * field only limits the number of files in the archive.
- */
- if ((int)archive_entry_ino(entry) > 0777777) {
+
+ ino = synthesize_ino_value(cpio, entry);
+ if (ino < 0) {
+ archive_set_error(&a->archive, ENOMEM,
+ "No memory for ino translation table");
+ return (ARCHIVE_FATAL);
+ } else if (ino > 0777777) {
archive_set_error(&a->archive, ERANGE,
- "large inode number truncated");
- ret = ARCHIVE_WARN;
+ "Too many files for this cpio format");
+ return (ARCHIVE_FATAL);
}
+ format_octal(ino & 0777777, &h.c_ino, sizeof(h.c_ino));
- format_octal(archive_entry_ino(entry) & 0777777, &h.c_ino, sizeof(h.c_ino));
format_octal(archive_entry_mode(entry), &h.c_mode, sizeof(h.c_mode));
format_octal(archive_entry_uid(entry), &h.c_uid, sizeof(h.c_uid));
format_octal(archive_entry_gid(entry), &h.c_gid, sizeof(h.c_gid));
@@ -170,6 +243,8 @@ archive_write_cpio_header(struct archive
if (p != NULL && *p != '\0')
ret = (a->compressor.write)(a, p, strlen(p));
+ if (ret == ARCHIVE_OK)
+ ret = ret2;
return (ret);
}
@@ -218,17 +293,15 @@ format_octal_recursive(int64_t v, char *
return (v);
v = format_octal_recursive(v, p+1, s-1);
*p = '0' + (v & 7);
- return (v >>= 3);
+ return (v >> 3);
}
static int
archive_write_cpio_finish(struct archive_write *a)
{
- struct cpio *cpio;
int er;
struct archive_entry *trailer;
- cpio = (struct cpio *)a->format_data;
trailer = archive_entry_new();
/* nlink = 1 here for GNU cpio compat. */
archive_entry_set_nlink(trailer, 1);
@@ -244,6 +317,7 @@ archive_write_cpio_destroy(struct archiv
struct cpio *cpio;
cpio = (struct cpio *)a->format_data;
+ free(cpio->ino_list);
free(cpio);
a->format_data = NULL;
return (ARCHIVE_OK);
@@ -253,7 +327,8 @@ static int
archive_write_cpio_finish_entry(struct archive_write *a)
{
struct cpio *cpio;
- int to_write, ret;
+ size_t to_write;
+ int ret;
cpio = (struct cpio *)a->format_data;
ret = ARCHIVE_OK;
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