From: Darrick J. Wong <djwong@xxxxxxxxxx>
Add some support code to libfrog so that client programs can walk file
descriptors and handles upwards through the directory tree; and obtain a
reasonable file path from a file descriptor/handle. This code will be
used in xfsprogs utilities.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
---
include/handle.h | 1
libfrog/Makefile | 2
libfrog/getparents.c | 345 ++++++++++++++++++++++++++++++++++++++++++++++++++
libfrog/getparents.h | 36 +++++
libfrog/paths.c | 167 ++++++++++++++++++++++++
libfrog/paths.h | 25 ++++
libhandle/handle.c | 7 +
7 files changed, 580 insertions(+), 3 deletions(-)
create mode 100644 libfrog/getparents.c
create mode 100644 libfrog/getparents.h
diff --git a/include/handle.h b/include/handle.h
index 34246f3854d..ba06500516c 100644
--- a/include/handle.h
+++ b/include/handle.h
@@ -17,6 +17,7 @@ struct parent;
extern int path_to_handle (char *__path, void **__hanp, size_t *__hlen);
extern int path_to_fshandle (char *__path, void **__fshanp, size_t *__fshlen);
extern int fd_to_handle (int fd, void **hanp, size_t *hlen);
+extern int handle_to_fsfd(void *, char **);
extern int handle_to_fshandle (void *__hanp, size_t __hlen, void **__fshanp,
size_t *__fshlen);
extern void free_handle (void *__hanp, size_t __hlen);
diff --git a/libfrog/Makefile b/libfrog/Makefile
index ad32b0674b2..8dd6ed68510 100644
--- a/libfrog/Makefile
+++ b/libfrog/Makefile
@@ -20,6 +20,7 @@ convert.c \
crc32.c \
file_exchange.c \
fsgeom.c \
+getparents.c \
histogram.c \
list_sort.c \
linux.c \
@@ -45,6 +46,7 @@ crc32table.h \
dahashselftest.h \
file_exchange.h \
fsgeom.h \
+getparents.h \
histogram.h \
logging.h \
paths.h \
diff --git a/libfrog/getparents.c b/libfrog/getparents.c
new file mode 100644
index 00000000000..89e1d3fa875
--- /dev/null
+++ b/libfrog/getparents.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017-2023 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@xxxxxxxxxx>
+ */
+#include "platform_defs.h"
+#include "xfs.h"
+#include "xfs_arch.h"
+#include "list.h"
+#include "libfrog/paths.h"
+#include "handle.h"
+#include "libfrog/getparents.h"
+
+/* Allocate a buffer large enough for some parent pointer records. */
+static inline struct xfs_getparents *
+alloc_pptr_buf(
+ size_t bufsize)
+{
+ struct xfs_getparents *pi;
+
+ pi = calloc(bufsize, 1);
+ if (!pi)
+ return NULL;
+ pi->gp_bufsize = bufsize;
+ return pi;
+}
+
+/*
+ * Walk all parents of the given file handle. Returns 0 on success or positive
+ * errno.
+ */
+static int
+call_getparents(
+ int fd,
+ struct xfs_handle *handle,
+ walk_parent_fn fn,
+ void *arg)
+{
+ struct xfs_getparents *pi;
+ struct xfs_getparents_rec *p;
+ unsigned int i;
+ ssize_t ret = -1;
+
+ pi = alloc_pptr_buf(XFS_XATTR_LIST_MAX);
+ if (!pi)
+ return errno;
+
+ if (handle) {
+ memcpy(&pi->gp_handle, handle, sizeof(struct xfs_handle));
+ pi->gp_flags = XFS_GETPARENTS_IFLAG_HANDLE;
+ }
+
+ ret = ioctl(fd, XFS_IOC_GETPARENTS, pi);
+ while (!ret) {
+ if (pi->gp_flags & XFS_GETPARENTS_OFLAG_ROOT) {
+ struct parent_rec rec = {
+ .p_flags = PARENT_IS_ROOT,
+ };
+
+ ret = fn(&rec, arg);
+ goto out_pi;
+ }
+
+ for (i = 0; i < pi->gp_count; i++) {
+ struct parent_rec rec = { 0 };
+
+ p = xfs_getparents_rec(pi, i);
+ rec.p_ino = p->gpr_ino;
+ rec.p_gen = p->gpr_gen;
+ strncpy((char *)rec.p_name, (char *)p->gpr_name,
+ MAXNAMELEN - 1);
+
+ ret = fn(&rec, arg);
+ if (ret)
+ goto out_pi;
+ }
+
+ if (pi->gp_flags & XFS_GETPARENTS_OFLAG_DONE)
+ break;
+
+ ret = ioctl(fd, XFS_IOC_GETPARENTS, pi);
+ }
+ if (ret)
+ ret = errno;
+
+out_pi:
+ free(pi);
+ return ret;
+}
+
+/* Walk all parent pointers of this handle. Returns 0 or positive errno. */
+int
+handle_walk_parents(
+ void *hanp,
+ size_t hlen,
+ walk_parent_fn fn,
+ void *arg)
+{
+ char *mntpt;
+ int fd;
+
+ if (hlen != sizeof(struct xfs_handle))
+ return EINVAL;
+
+ fd = handle_to_fsfd(hanp, &mntpt);
+ if (fd < 0)
+ return errno;
+
+ return call_getparents(fd, hanp, fn, arg);
+}
+
+/* Walk all parent pointers of this fd. Returns 0 or positive errno. */
+int
+fd_walk_parents(
+ int fd,
+ walk_parent_fn fn,
+ void *arg)
+{
+ return call_getparents(fd, NULL, fn, arg);
+}
+
+struct walk_ppaths_info {
+ walk_path_fn fn;
+ void *arg;
+ char *mntpt;
+ struct path_list *path;
+ int fd;
+};
+
+struct walk_ppath_level_info {
+ struct xfs_handle newhandle;
+ struct path_component *pc;
+ struct walk_ppaths_info *wpi;
+};
+
+static int handle_walk_ppath(struct walk_ppaths_info *wpi,
+ struct xfs_handle *handle);
+
+static int
+handle_walk_ppath_rec(
+ const struct parent_rec *rec,
+ void *arg)
+{
+ struct walk_ppath_level_info *wpli = arg;
+ struct walk_ppaths_info *wpi = wpli->wpi;
+ int ret = 0;
+
+ if (rec->p_flags & PARENT_IS_ROOT)
+ return wpi->fn(wpi->mntpt, wpi->path, wpi->arg);
+
+ ret = path_component_change(wpli->pc, rec->p_name,
+ strlen((char *)rec->p_name), rec->p_ino);
+ if (ret)
+ return ret;
+
+ wpli->newhandle.ha_fid.fid_ino = rec->p_ino;
+ wpli->newhandle.ha_fid.fid_gen = rec->p_gen;
+
+ path_list_add_parent_component(wpi->path, wpli->pc);
+ ret = handle_walk_ppath(wpi, &wpli->newhandle);
+ path_list_del_component(wpi->path, wpli->pc);
+
+ return ret;
+}
+
+/*
+ * Recursively walk all parents of the given file handle; if we hit the
+ * fs root then we call the associated function with the constructed path.
+ * Returns 0 for success or positive errno.
+ */
+static int
+handle_walk_ppath(
+ struct walk_ppaths_info *wpi,
+ struct xfs_handle *handle)
+{
+ struct walk_ppath_level_info *wpli;
+ int ret;
+
+ wpli = malloc(sizeof(struct walk_ppath_level_info));
+ if (!wpli)
+ return errno;
+ wpli->pc = path_component_init("", 0);
+ if (!wpli->pc) {
+ ret = errno;
+ free(wpli);
+ return ret;
+ }
+ wpli->wpi = wpi;
+ memcpy(&wpli->newhandle, handle, sizeof(struct xfs_handle));
+
+ ret = call_getparents(wpi->fd, handle, handle_walk_ppath_rec, wpli);
+
+ path_component_free(wpli->pc);
+ free(wpli);
+ return ret;
+}
+
+/*
+ * Call the given function on all known paths from the vfs root to the inode
+ * described in the handle. Returns 0 for success or positive errno.
+ */
+int
+handle_walk_parent_paths(
+ void *hanp,
+ size_t hlen,
+ walk_path_fn fn,
+ void *arg)
+{
+ struct walk_ppaths_info wpi;
+ ssize_t ret;
+
+ if (hlen != sizeof(struct xfs_handle))
+ return EINVAL;
+
+ wpi.fd = handle_to_fsfd(hanp, &wpi.mntpt);
+ if (wpi.fd < 0)
+ return errno;
+ wpi.path = path_list_init();
+ if (!wpi.path)
+ return errno;
+ wpi.fn = fn;
+ wpi.arg = arg;
+
+ ret = handle_walk_ppath(&wpi, hanp);
+ path_list_free(wpi.path);
+
+ return ret;
+}
+
+/*
+ * Call the given function on all known paths from the vfs root to the inode
+ * referred to by the file description. Returns 0 or positive errno.
+ */
+int
+fd_walk_parent_paths(
+ int fd,
+ walk_path_fn fn,
+ void *arg)
+{
+ struct walk_ppaths_info wpi;
+ void *hanp;
+ size_t hlen;
+ int fsfd;
+ int ret;
+
+ ret = fd_to_handle(fd, &hanp, &hlen);
+ if (ret)
+ return errno;
+
+ fsfd = handle_to_fsfd(hanp, &wpi.mntpt);
+ if (fsfd < 0)
+ return errno;
+ wpi.fd = fd;
+ wpi.path = path_list_init();
+ if (!wpi.path)
+ return errno;
+ wpi.fn = fn;
+ wpi.arg = arg;
+
+ ret = handle_walk_ppath(&wpi, hanp);
+ path_list_free(wpi.path);
+
+ return ret;
+}
+
+struct path_walk_info {
+ char *buf;
+ size_t len;
+ size_t written;
+};
+
+/* Helper that stringifies the first full path that we find. */
+static int
+handle_to_path_walk(
+ const char *mntpt,
+ const struct path_list *path,
+ void *arg)
+{
+ struct path_walk_info *pwi = arg;
+ int mntpt_len = strlen(mntpt);
+ int ret;
+
+ /* Trim trailing slashes from the mountpoint */
+ while (mntpt_len > 0 && mntpt[mntpt_len - 1] == '/')
+ mntpt_len--;
+
+ ret = snprintf(pwi->buf, pwi->len, "%.*s", mntpt_len, mntpt);
+ if (ret != mntpt_len)
+ return ENAMETOOLONG;
+ pwi->written += ret;
+
+ ret = path_list_to_string(path, pwi->buf + ret, pwi->len - ret);
+ if (ret < 0)
+ return ENAMETOOLONG;
+
+ pwi->written += ret;
+ return ECANCELED;
+}
+
+/*
+ * Return any eligible path to this file handle. Returns 0 for success or
+ * positive errno.
+ */
+int
+handle_to_path(
+ void *hanp,
+ size_t hlen,
+ char *path,
+ size_t pathlen)
+{
+ struct path_walk_info pwi = { .buf = path, .len = pathlen };
+ int ret;
+
+ ret = handle_walk_parent_paths(hanp, hlen, handle_to_path_walk, &pwi);
+ if (ret && ret != ECANCELED)
+ return ret;
+ if (!pwi.written)
+ return ENODATA;
+
+ path[pwi.written] = 0;
+ return 0;
+}
+
+/*
+ * Return any eligible path to this file description. Returns 0 for success
+ * or positive errno.
+ */
+int
+fd_to_path(
+ int fd,
+ char *path,
+ size_t pathlen)
+{
+ struct path_walk_info pwi = { .buf = path, .len = pathlen };
+ int ret;
+
+ ret = fd_walk_parent_paths(fd, handle_to_path_walk, &pwi);
+ if (ret && ret != ECANCELED)
+ return ret;
+ if (!pwi.written)
+ return ENODATA;
+
+ path[pwi.written] = 0;
+ return ret;
+}
diff --git a/libfrog/getparents.h b/libfrog/getparents.h
new file mode 100644
index 00000000000..c95efed245a
--- /dev/null
+++ b/libfrog/getparents.h
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2023 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@xxxxxxxxxx>
+ */
+#ifndef __LIBFROG_GETPARENTS_H_
+#define __LIBFROG_GETPARENTS_H_
+
+struct path_list;
+
+struct parent_rec {
+ uint64_t p_ino;
+ uint32_t p_gen;
+ uint32_t p_flags;
+ unsigned char p_name[MAXNAMELEN];
+};
+
+/* This is the root directory. */
+#define PARENT_IS_ROOT (1U << 0)
+
+typedef int (*walk_parent_fn)(const struct parent_rec *rec, void *arg);
+typedef int (*walk_path_fn)(const char *mntpt, const struct path_list *path,
+ void *arg);
+
+int fd_walk_parents(int fd, walk_parent_fn fn, void *arg);
+int handle_walk_parents(void *hanp, size_t hanlen, walk_parent_fn fn,
+ void *arg);
+
+int fd_walk_parent_paths(int fd, walk_path_fn fn, void *arg);
+int handle_walk_parent_paths(void *hanp, size_t hanlen, walk_path_fn fn,
+ void *arg);
+
+int fd_to_path(int fd, char *path, size_t pathlen);
+int handle_to_path(void *hanp, size_t hlen, char *path, size_t pathlen);
+
+#endif /* __LIBFROG_GETPARENTS_H_ */
diff --git a/libfrog/paths.c b/libfrog/paths.c
index abb29a237e8..4b9c8c64489 100644
--- a/libfrog/paths.c
+++ b/libfrog/paths.c
@@ -15,6 +15,7 @@
#include "paths.h"
#include "input.h"
#include "projects.h"
+#include "list.h"
#include <limits.h>
extern char *progname;
@@ -563,3 +564,169 @@ fs_table_insert_project_path(
return error;
}
+
+/* Structured path components. */
+
+struct path_list {
+ struct list_head p_head;
+};
+
+struct path_component {
+ struct list_head pc_list;
+ uint64_t pc_ino;
+ char *pc_fname;
+};
+
+/* Initialize a path component with a given name. */
+struct path_component *
+path_component_init(
+ const char *name,
+ uint64_t ino)
+{
+ struct path_component *pc;
+
+ pc = malloc(sizeof(struct path_component));
+ if (!pc)
+ return NULL;
+ INIT_LIST_HEAD(&pc->pc_list);
+ pc->pc_fname = strdup(name);
+ if (!pc->pc_fname) {
+ free(pc);
+ return NULL;
+ }
+ pc->pc_ino = ino;
+ return pc;
+}
+
+/* Free a path component. */
+void
+path_component_free(
+ struct path_component *pc)
+{
+ free(pc->pc_fname);
+ free(pc);
+}
+
+/* Change a path component's filename or returns positive errno. */
+int
+path_component_change(
+ struct path_component *pc,
+ const void *name,
+ size_t namelen,
+ uint64_t ino)
+{
+ void *p;
+
+ p = realloc(pc->pc_fname, namelen + 1);
+ if (!p)
+ return errno;
+ pc->pc_fname = p;
+ memcpy(pc->pc_fname, name, namelen);
+ pc->pc_fname[namelen] = 0;
+ pc->pc_ino = ino;
+ return 0;
+}
+
+/* Initialize a pathname or returns positive errno. */
+struct path_list *
+path_list_init(void)
+{
+ struct path_list *path;
+
+ path = malloc(sizeof(struct path_list));
+ if (!path)
+ return NULL;
+ INIT_LIST_HEAD(&path->p_head);
+ return path;
+}
+
+/* Empty out a pathname. */
+void
+path_list_free(
+ struct path_list *path)
+{
+ struct path_component *pos;
+ struct path_component *n;
+
+ list_for_each_entry_safe(pos, n, &path->p_head, pc_list) {
+ path_list_del_component(path, pos);
+ path_component_free(pos);
+ }
+ free(path);
+}
+
+/* Add a parent component to a pathname. */
+void
+path_list_add_parent_component(
+ struct path_list *path,
+ struct path_component *pc)
+{
+ list_add(&pc->pc_list, &path->p_head);
+}
+
+/* Add a component to a pathname. */
+void
+path_list_add_component(
+ struct path_list *path,
+ struct path_component *pc)
+{
+ list_add_tail(&pc->pc_list, &path->p_head);
+}
+
+/* Remove a component from a pathname. */
+void
+path_list_del_component(
+ struct path_list *path,
+ struct path_component *pc)
+{
+ list_del_init(&pc->pc_list);
+}
+
+/*
+ * Convert a pathname into a string or returns -1 if the buffer isn't long
+ * enough.
+ */
+ssize_t
+path_list_to_string(
+ const struct path_list *path,
+ char *buf,
+ size_t buflen)
+{
+ struct path_component *pos;
+ char *buf_end = buf + buflen;
+ ssize_t bytes = 0;
+ int ret;
+
+ list_for_each_entry(pos, &path->p_head, pc_list) {
+ if (buf >= buf_end)
+ return -1;
+
+ ret = snprintf(buf, buflen, "/%s", pos->pc_fname);
+ if (ret < 0 || ret >= buflen)
+ return -1;
+
+ bytes += ret;
+ buf += ret;
+ buflen -= ret;
+ }
+ return bytes;
+}
+
+/* Walk each component of a path. */
+int
+path_walk_components(
+ const struct path_list *path,
+ path_walk_fn_t fn,
+ void *arg)
+{
+ struct path_component *pos;
+ int ret;
+
+ list_for_each_entry(pos, &path->p_head, pc_list) {
+ ret = fn(pos->pc_fname, pos->pc_ino, arg);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
diff --git a/libfrog/paths.h b/libfrog/paths.h
index f20a2c3ef58..6be74c42b07 100644
--- a/libfrog/paths.h
+++ b/libfrog/paths.h
@@ -58,4 +58,29 @@ typedef struct fs_cursor {
extern void fs_cursor_initialise(char *__dir, uint __flags, fs_cursor_t *__cp);
extern fs_path_t *fs_cursor_next_entry(fs_cursor_t *__cp);
+/* Path information. */
+
+struct path_list;
+struct path_component;
+
+struct path_component *path_component_init(const char *name, uint64_t ino);
+void path_component_free(struct path_component *pc);
+int path_component_change(struct path_component *pc, const void *name,
+ size_t namelen, uint64_t ino);
+
+struct path_list *path_list_init(void);
+void path_list_free(struct path_list *path);
+void path_list_add_parent_component(struct path_list *path,
+ struct path_component *pc);
+void path_list_add_component(struct path_list *path, struct path_component *pc);
+void path_list_del_component(struct path_list *path, struct path_component *pc);
+
+ssize_t path_list_to_string(const struct path_list *path, char *buf,
+ size_t buflen);
+
+typedef int (*path_walk_fn_t)(const char *name, uint64_t ino, void *arg);
+
+int path_walk_components(const struct path_list *path, path_walk_fn_t fn,
+ void *arg);
+
#endif /* __LIBFROG_PATH_H__ */
diff --git a/libhandle/handle.c b/libhandle/handle.c
index 333c2190900..1e8fe9ac5f1 100644
--- a/libhandle/handle.c
+++ b/libhandle/handle.c
@@ -29,7 +29,6 @@ typedef union {
} comarg_t;
static int obj_to_handle(char *, int, unsigned int, comarg_t, void**, size_t*);
-static int handle_to_fsfd(void *, char **);
static char *path_to_fspath(char *path);
@@ -203,8 +202,10 @@ handle_to_fshandle(
return 0;
}
-static int
-handle_to_fsfd(void *hanp, char **path)
+int
+handle_to_fsfd(
+ void *hanp,
+ char **path)
{
struct fdhash *fdhp;
