#include "common.h"
#include <hash.h>
+/* Error number to use when an impostor is discovered.
+ Pretend the impostor isn't there. */
+enum { IMPOSTOR_ERRNO = ENOENT };
+
struct link
{
dev_t dev;
}
enum exclusion_tag_type
-check_exclusion_tags (int fd, char const **tag_file_name)
+check_exclusion_tags (struct tar_stat_info const *st, char const **tag_file_name)
{
struct exclusion_tag *tag;
for (tag = exclusion_tags; tag; tag = tag->next)
{
- int tagfd = openat (fd, tag->name, open_read_flags);
+ int tagfd = subfile_open (st, tag->name, open_read_flags);
if (0 <= tagfd)
{
bool satisfied = !tag->predicate || tag->predicate (tagfd);
memset (blk->buffer + size_left, 0, BLOCKSIZE - count);
}
- count = (fd < 0) ? bufsize : safe_read (fd, blk->buffer, bufsize);
+ count = (fd <= 0) ? bufsize : safe_read (fd, blk->buffer, bufsize);
if (count == SAFE_READ_ERROR)
{
read_diag_details (st->orig_file_name,
char *name_buf;
size_t name_size;
- switch (check_exclusion_tags (st->fd, &tag_file_name))
+ switch (check_exclusion_tags (st, &tag_file_name))
{
case exclusion_tag_all:
/* Handled in dump_file0 */
(*pstr)[len] = '\0';
}
+/* If we just ran out of file descriptors, release a file descriptor
+ in the directory chain somewhere leading from DIR->parent->parent
+ up through the root. Return true if successful, false (preserving
+ errno == EMFILE) otherwise.
+
+ Do not release DIR's file descriptor, or DIR's parent, as other
+ code assumes that they work. On some operating systems, another
+ process can claim file descriptor resources as we release them, and
+ some calls or their emulations require multiple file descriptors,
+ so callers should not give up if a single release doesn't work. */
+
static bool
-dump_dir (struct tar_stat_info *st)
+open_failure_recover (struct tar_stat_info const *dir)
+{
+ if (errno == EMFILE && dir && dir->parent)
+ {
+ struct tar_stat_info *p;
+ for (p = dir->parent->parent; p; p = p->parent)
+ if (0 < p->fd && (! p->parent || p->parent->fd <= 0))
+ {
+ tar_stat_close (p);
+ return true;
+ }
+ errno = EMFILE;
+ }
+
+ return false;
+}
+
+/* Return the directory entries of ST, in a dynamically allocated buffer,
+ each entry followed by '\0' and the last followed by an extra '\0'.
+ Return null on failure, setting errno. */
+char *
+get_directory_entries (struct tar_stat_info *st)
{
- char *directory = 0;
- int dupfd = dup (st->fd);
- if (0 <= dupfd)
+ DIR *dirstream;
+ while (! (dirstream = fdopendir (st->fd)) && open_failure_recover (st))
+ continue;
+
+ if (! dirstream)
+ return 0;
+ else
{
- directory = fdsavedir (dupfd);
- if (! directory)
+ char *entries = streamsavedir (dirstream);
+ int streamsavedir_errno = errno;
+
+ int fd = dirfd (dirstream);
+ if (fd < 0)
{
- int e = errno;
- close (dupfd);
- errno = e;
+ /* The dirent.h implementation doesn't use file descriptors
+ for directory streams, so open the directory again. */
+ char const *name = st->orig_file_name;
+ if (closedir (dirstream) != 0)
+ close_diag (name);
+ dirstream = 0;
+ fd = subfile_open (st->parent,
+ st->parent ? last_component (name) : name,
+ open_searchdir_flags);
+ if (fd < 0)
+ fd = - errno;
+ else
+ {
+ struct stat dirst;
+ if (! (fstat (fd, &dirst) == 0
+ && st->stat.st_ino == dirst.st_ino
+ && st->stat.st_dev == dirst.st_dev))
+ {
+ close (fd);
+ fd = - IMPOSTOR_ERRNO;
+ }
+ }
}
+
+ st->fd = fd;
+ st->dirstream = dirstream;
+ errno = streamsavedir_errno;
+ return entries;
}
+}
+
+/* Dump the directory ST. Return true if successful, false (emitting
+ diagnostics) otherwise. Get ST's entries, recurse through its
+ subdirectories, and clean up file descriptors afterwards. */
+static bool
+dump_dir (struct tar_stat_info *st)
+{
+ char *directory = get_directory_entries (st);
if (! directory)
{
savedir_diag (st->orig_file_name);
dump_dir0 (st, directory);
+ restore_parent_fd (st);
free (directory);
return true;
}
{
if (! st.orig_file_name)
{
- st.orig_file_name = xstrdup (p->name);
- st.fd = open (st.orig_file_name,
- ((open_read_flags - O_RDONLY
- + O_SEARCH)
- | O_DIRECTORY));
- if (st.fd < 0)
+ int fd = open (p->name, open_searchdir_flags);
+ if (fd < 0)
{
open_diag (p->name);
break;
}
- if (fstat (st.fd, &st.stat) != 0)
+ st.fd = fd;
+ if (fstat (fd, &st.stat) != 0)
{
stat_diag (p->name);
break;
}
+ st.orig_file_name = xstrdup (p->name);
}
if (buffer_size < plen + qlen)
{
}
}
+/* Assuming DIR is the working directory, open FILE, using FLAGS to
+ control the open. A null DIR means to use ".". If we are low on
+ file descriptors, try to release one or more from DIR's parents to
+ reuse it. */
+int
+subfile_open (struct tar_stat_info const *dir, char const *file, int flags)
+{
+ int fd;
+
+ static bool initialized;
+ if (! initialized)
+ {
+ /* Initialize any tables that might be needed when file
+ descriptors are exhausted, and whose initialization might
+ require a file descriptor. This includes the system message
+ catalog and tar's message catalog. */
+ initialized = true;
+ strerror (ENOENT);
+ gettext ("");
+ }
+
+ while ((fd = openat (dir ? dir->fd : AT_FDCWD, file, flags)) < 0
+ && open_failure_recover (dir))
+ continue;
+ return fd;
+}
+
+/* Restore the file descriptor for ST->parent, if it was temporarily
+ closed to conserve file descriptors. On failure, set the file
+ descriptor to the negative of the corresponding errno value. Call
+ this every time a subdirectory is ascended from. */
+void
+restore_parent_fd (struct tar_stat_info const *st)
+{
+ struct tar_stat_info *parent = st->parent;
+ if (parent && ! parent->fd)
+ {
+ int parentfd = openat (st->fd, "..", open_searchdir_flags);
+ struct stat parentstat;
+
+ if (parentfd < 0)
+ parentfd = - errno;
+ else if (! (fstat (parentfd, &parentstat) == 0
+ && parent->stat.st_ino == parentstat.st_ino
+ && parent->stat.st_dev == parentstat.st_dev))
+ {
+ close (parentfd);
+ parentfd = IMPOSTOR_ERRNO;
+ }
+
+ if (parentfd < 0)
+ {
+ int origfd = open (parent->orig_file_name, open_searchdir_flags);
+ if (0 <= origfd)
+ {
+ if (fstat (parentfd, &parentstat) == 0
+ && parent->stat.st_ino == parentstat.st_ino
+ && parent->stat.st_dev == parentstat.st_dev)
+ parentfd = origfd;
+ else
+ close (origfd);
+ }
+ }
+
+ parent->fd = parentfd;
+ }
+}
+
/* Dump a single file, recursing on directories. ST is the file's
status info, NAME its name relative to the parent directory, and P
its full name (which may be relative to the working directory). */
struct timespec original_ctime;
struct timespec restore_times[2];
off_t block_ordinal = -1;
- int fd = -1;
+ int fd = 0;
bool is_dir;
- bool top_level = ! st->parent;
- int parentfd = top_level ? AT_FDCWD : st->parent->fd;
+ struct tar_stat_info const *parent = st->parent;
+ bool top_level = ! parent;
+ int parentfd = top_level ? AT_FDCWD : parent->fd;
void (*diag) (char const *) = 0;
if (interactive_option && !confirm ("add", p))
transform_name (&st->file_name, XFORM_REGFILE);
- if (fstatat (parentfd, name, &st->stat, fstatat_flags) != 0)
+ if (parentfd < 0 && ! top_level)
+ {
+ errno = - parentfd;
+ diag = open_diag;
+ }
+ else if (fstatat (parentfd, name, &st->stat, fstatat_flags) != 0)
diag = stat_diag;
else if (file_dumpable_p (&st->stat))
{
- fd = st->fd = openat (parentfd, name, open_read_flags);
+ fd = subfile_open (parent, name, open_read_flags);
if (fd < 0)
diag = open_diag;
- else if (fstat (fd, &st->stat) != 0)
- diag = stat_diag;
+ else
+ {
+ st->fd = fd;
+ if (fstat (fd, &st->stat) != 0)
+ diag = stat_diag;
+ }
}
if (diag)
{
ensure_slash (&st->orig_file_name);
ensure_slash (&st->file_name);
- if (check_exclusion_tags (fd, &tag_file_name) == exclusion_tag_all)
+ if (check_exclusion_tags (st, &tag_file_name) == exclusion_tag_all)
{
exclusion_tag_warning (st->orig_file_name, tag_file_name,
_("directory not dumped"));
}
ok = dump_dir (st);
+
+ fd = st->fd;
+ parentfd = top_level ? AT_FDCWD : parent->fd;
}
else
{
enum dump_status status;
- if (fd != -1 && sparse_option && ST_IS_SPARSE (st->stat))
+ if (fd && sparse_option && ST_IS_SPARSE (st->stat))
{
status = sparse_dump_file (fd, st);
if (status == dump_status_not_implemented)
if (ok)
{
- if ((fd < 0
- ? fstatat (parentfd, name, &final_stat, fstatat_flags)
- : fstat (fd, &final_stat))
- != 0)
+ if (fd < 0)
{
- file_removed_diag (p, top_level, stat_diag);
+ errno = - fd;
ok = false;
}
+ else if (fd == 0)
+ {
+ if (parentfd < 0 && ! top_level)
+ {
+ errno = - parentfd;
+ ok = false;
+ }
+ else
+ ok = fstatat (parentfd, name, &final_stat, fstatat_flags) == 0;
+ }
+ else
+ ok = fstat (fd, &final_stat) == 0;
+
+ if (! ok)
+ file_removed_diag (p, top_level, stat_diag);
}
if (ok)
utime_error (p);
}
- if (0 < fd)
- {
- if (close (fd) != 0)
- {
- close_diag (p);
- ok = false;
- }
- st->fd = 0;
- }
-
+ ok &= tar_stat_close (st);
if (ok && remove_files_option)
queue_deferred_unlink (p, is_dir);
projects / chaz / tar / blobdiff