bookmarkctl: add sub-commands for xattr

Provides platform-agnostic command-line interface for managing
extended attributes on a BookmarkFS filesystem.

src/Makefile.am

@@ -9,7 +9,8 @@
 bin_PROGRAMS       =
 pkginclude_HEADERS = backend.h common.h ioctl.h fsck_handler.h version.h
 noinst_HEADERS     = backend_util.h db.h defs.h frontend_util.h fs_ops.h  \
-                     fsck_ops.h fsck_util.h json.h lib.h macros.h uuid.h xstd.h
+                     fsck_ops.h fsck_util.h json.h lib.h macros.h uuid.h  \
+                     xattr.h xstd.h
 lib_LTLIBRARIES    =
 pkglib_LTLIBRARIES =
 
@@ -56,7 +57,7 @@ if BOOKMARKCTL
   bin_PROGRAMS += bookmarkctl
 
   bookmarkctl_CPPFLAGS = $(BASE_CPPFLAGS_)
-  bookmarkctl_SOURCES  = bookmarkctl.c fsck_util.c
+  bookmarkctl_SOURCES  = bookmarkctl.c fsck_util.c xattr.c xstd.c
 endif  # BOOKMARKCTL
 
 if BOOKMARKFS_FSCK

src/bookmarkctl.c

@@ -24,6 +24,7 @@
 #  include "config.h"
 #endif
 
+#include <ctype.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -37,14 +38,34 @@
 #include "ioctl.h"
 #include "macros.h"
 #include "version.h"
+#include "xattr.h"
 #include "xstd.h"
 
+#define BMCTL_XATTR_GET_NOEOL   (1u << 0)
+#define BMCTL_XATTR_GET_BINARY  (1u << 1)
+#define BMCTL_XATTR_GET_MULTI   (1u << 2)
+#define BMCTL_XATTR_GET_QUIET   (1u << 3)
+
+struct xattr_get_ctx {
+    char const *prefix;
+    char        sep;
+    char        eol;
+    uint32_t    flags;
+};
+
 // Forward declaration start
-static int  dispatch_subcmds (int, char *[]);
+static int  dispatch_subcmds  (int, char *[]);
-static void print_help       (void);
+static void print_help        (void);
-static void print_version    (void);
+static void print_version     (void);
-static int  subcmd_fsck      (int, char *[]);
+static int  subcmd_fsck       (int, char *[]);
-static int  subcmd_permd     (int, char *[]);
+static int  subcmd_permd      (int, char *[]);
+static int  subcmd_xattr_get  (int, char *[]);
+static int  subcmd_xattr_list (int, char *[]);
+static int  subcmd_xattr_set  (int, char *[]);
+static int  xattr_get_cb      (void *, void *, size_t);
+static int  xattr_get_one     (char const *, char *[], int,
+                               struct xattr_get_ctx *);
+static int  xattr_list_cb     (void *, void *, size_t);
 // Forward declaration end
 
 static int
@@ -61,6 +82,12 @@ dispatch_subcmds (
     int status = 0;
     if (0 == strcmp("permd", cmd)) {
         status = subcmd_permd(argc, argv);
+    } else if (0 == strcmp("xattr-get", cmd)) {
+        status = subcmd_xattr_get(argc, argv);
+    } else if (0 == strcmp("xattr-set", cmd)) {
+        status = subcmd_xattr_set(argc, argv);
+    } else if (0 == strcmp("xattr-list", cmd)) {
+        status = subcmd_xattr_list(argc, argv);
     } else if (0 == strcmp("fsck", cmd)) {
         status = subcmd_fsck(argc, argv);
     } else if (0 == strcmp("help", cmd)) {
@@ -80,8 +107,11 @@ print_help (void)
     puts("Usage: bookmarkctl <cmd> [args]\n"
             "\n"
             "Main commands:\n"
-            "  permd    Permute directory entries\n"
+            "  permd         Permute directory entries\n"
-            "  fsck     Check filesystem\n"
+            "  fsck          Check filesystem\n"
+            "  xattr-list    List extended attribute names\n"
+            "  xattr-get     Get extended attribute value\n"
+            "  xattr-set     Set extended attribute value\n"
             "\n"
             "Other commands:\n"
             "  help       Print help message\n"
@@ -202,6 +232,222 @@ subcmd_permd (
     return status;
 }
 
+static int
+subcmd_xattr_get (
+    int   argc,
+    char *argv[]
+) {
+    struct xattr_get_ctx ctx = {
+        .sep = '\t',
+        .eol = '\n',
+    };
+
+    OPT_START(argc, argv, "n:Nbmqs:")
+    OPT_OPT('n') {
+        ctx.eol = optarg[0];
+        break;
+    }
+    OPT_OPT('N') {
+        ctx.flags |= BMCTL_XATTR_GET_NOEOL;
+        break;
+    }
+    OPT_OPT('b') {
+        ctx.flags |= BMCTL_XATTR_GET_BINARY;
+        break;
+    }
+    OPT_OPT('m') {
+        ctx.flags |= BMCTL_XATTR_GET_MULTI;
+        break;
+    }
+    OPT_OPT('q') {
+        ctx.flags |= BMCTL_XATTR_GET_QUIET;
+        break;
+    }
+    OPT_OPT('s') {
+        ctx.sep = optarg[0];
+        break;
+    }
+    OPT_NOVAL
+    OPT_END
+
+    if (argc < 2) {
+        log_puts("xattr-get: xattr name and file path must be specified");
+        return -1;
+    }
+
+    if (ctx.flags & BMCTL_XATTR_GET_MULTI) {
+        return xattr_get_one(argv[argc - 1], argv, argc - 1, &ctx);
+    }
+    for (int i = 1; i < argc; ++i) {
+        char const *path = argv[i];
+        if (0 != xattr_get_one(path, argv, 1, &ctx)) {
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static int
+subcmd_xattr_list (
+    int   argc,
+    char *argv[]
+) {
+    if (--argc != 1) {
+        if (argc < 1) {
+            log_puts("xattr-set: file path must be provided");
+        } else {
+            log_puts("xattr-set: too many arguments");
+        }
+        return -1;
+    }
+    char const *path = *(++argv);
+
+    int fd = bookmarkfs_xattr_open(path);
+    if (fd < 0) {
+        return -1;
+    }
+    int status = bookmarkfs_xattr_list(fd, xattr_list_cb, NULL);
+    close(fd);
+    return status;
+}
+
+static int
+subcmd_xattr_set (
+    int   argc,
+    char *argv[]
+) {
+    char *val = NULL;
+
+    OPT_START(argc, argv, "v:")
+    OPT_OPT('v') {
+        val = optarg;
+        break;
+    }
+    OPT_NOVAL
+    OPT_END
+
+    if (argc != 2) {
+        if (argc < 2) {
+            log_puts("xattr-set: xattr name and file path must be specified");
+        } else {
+            log_puts("xattr-set: too many arguments");
+        }
+        return -1;
+    }
+    char const *name = argv[0];
+    char const *path = argv[1];
+
+    int fd = bookmarkfs_xattr_open(path);
+    if (fd < 0) {
+        return -1;
+    }
+    int status = -1;
+
+    size_t  val_size = 0;
+    char   *buf      = val;
+    if (buf == NULL) {
+        size_t buf_size = 4096;
+        buf = xmalloc(buf_size);
+        do {
+            if (val_size == buf_size) {
+                buf_size += buf_size >> 1;
+                buf = xrealloc(buf, buf_size);
+            }
+            val_size += fread(buf + val_size, 1, buf_size - val_size, stdin);
+            if (ferror(stdin)) {
+                log_printf("fread(): %s", strerror(errno));
+                goto end;
+            }
+        } while (!feof(stdin));
+    } else {
+        val_size = strlen(buf);
+    }
+    status = bookmarkfs_xattr_set(fd, name, buf, val_size);
+
+  end:
+    if (val == NULL) {
+        free(buf);
+    }
+    close(fd);
+    return status;
+}
+
+static int
+xattr_get_cb (
+    void   *user_data,
+    void   *buf,
+    size_t  buf_len
+) {
+    struct xattr_get_ctx const *ctx = user_data;
+
+    uint32_t flags = ctx->flags;
+    if (!(flags & BMCTL_XATTR_GET_QUIET)) {
+        if (0 > printf("%s%c", ctx->prefix, ctx->sep)) {
+            log_printf("printf(): %s", strerror(errno));
+            return -1;
+        }
+    }
+    if (!(flags & BMCTL_XATTR_GET_BINARY)) {
+        for (unsigned char *s = buf, *end = s; s < end; ++s) {
+            if (iscntrl(*s)) {
+                *s = '?';
+            }
+        }
+    }
+    if (buf_len != fwrite(buf, 1, buf_len, stdout)) {
+        log_printf("fwrite(): %s", strerror(errno));
+        return -1;
+    }
+    if (!(flags & BMCTL_XATTR_GET_NOEOL)) {
+        if (EOF == fputc(ctx->eol, stdout)) {
+            log_printf("fputc(): %s", strerror(errno));
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static int
+xattr_get_one (
+    char const           *path,
+    char                 *names[],
+    int                   names_cnt,
+    struct xattr_get_ctx *ctx
+) {
+    int fd = bookmarkfs_xattr_open(path);
+    if (fd < 0) {
+        return -1;
+    }
+
+    int status;
+    for (int i = 0; i < names_cnt; ++i) {
+        char const *name = names[i];
+
+        ctx->prefix = (ctx->flags & BMCTL_XATTR_GET_MULTI) ? name : path;
+        status = bookmarkfs_xattr_get(fd, name, xattr_get_cb, ctx);
+        if (status < 0) {
+            goto end;
+        }
+    }
+
+  end:
+    close(fd);
+    return status;
+}
+
+static int
+xattr_list_cb (
+    void   *UNUSED_VAR(user_data),
+    void   *buf,
+    size_t  buf_len
+) {
+    if (0 > printf("%.*s\n", (int)buf_len, (char *)buf)) {
+        log_printf("printf(): %s", strerror(errno));
+        return -1;
+    }
+    return 0;
+}
+
 int
 main (
     int   argc,

src/xattr.c

@@ -0,0 +1,254 @@
+/**
+ * bookmarkfs/src/xattr.c
+ * ----
+ *
+ * Copyright (C) 2025  CismonX <admin@cismon.net>
+ *
+ * This file is part of BookmarkFS.
+ *
+ * BookmarkFS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * BookmarkFS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with BookmarkFS.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "xattr.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <fcntl.h>
+#if defined(__linux__)
+#  include <sys/xattr.h>
+#elif defined(__FreeBSD__)
+#  include <sys/extattr.h>
+#endif
+
+#include "xstd.h"
+
+#if defined(__linux__)
+#  define XATTR_NAME_PREFIX  BOOKMARKFS_XATTR_PREFIX
+#elif defined(__FreeBSD__)
+#  define XATTR_NAME_PREFIX  ( &BOOKMARKFS_XATTR_PREFIX[strlen("user.")] )
+#endif
+
+// Forward declaration start
+static ssize_t xattr_do_get         (int, char const *, void *, size_t);
+static ssize_t xattr_do_list        (int, void *, size_t);
+static int     xattr_do_set         (int, char const *, void const *, size_t);
+static char *  xattr_normalize_name (char const *);
+// Forward declaration end
+
+static ssize_t
+xattr_do_get (
+    int         fd,
+    char const *name,
+    void       *buf,
+    size_t      buf_len
+) {
+    ssize_t result;
+#if defined(__linux__)
+    result = fgetxattr(fd, name, buf, buf_len);
+    if (result < 0) {
+        log_printf("fgetxattr(): %s", strerror(errno));
+    }
+#elif defined(__FreeBSD__)
+    result = extattr_get_fd(fd, EXTATTR_NAMESPACE_USER, name, buf, buf_len);
+    if (result < 0) {
+        log_printf("extattr_get_fd(): %s", strerror(errno));
+    }
+#else
+#  error "not implemented"
+#endif
+    return result;
+}
+
+static ssize_t
+xattr_do_list (
+    int     fd,
+    void   *buf,
+    size_t  buf_len
+) {
+    ssize_t result;
+#if defined(__linux__)
+    result = flistxattr(fd, buf, buf_len);
+    if (result < 0) {
+        log_printf("flistxattr(): %s", strerror(errno));
+    }
+#elif defined(__FreeBSD__)
+    result = extattr_list_fd(fd, EXTATTR_NAMESPACE_USER, buf, buf_len);
+    if (result < 0) {
+        log_printf("extattr_list_fd(): %s", strerror(errno));
+    }
+#else
+#  error "not implemented"
+#endif
+    return result;
+}
+
+static int
+xattr_do_set (
+    int         fd,
+    char const *name,
+    void const *buf,
+    size_t      buf_len
+) {
+#if defined(__linux__)
+    if (0 != fsetxattr(fd, name, buf, buf_len, 0)) {
+        log_printf("fsetxattr(): %s", strerror(errno));
+        return -1;
+    }
+#elif defined(__FreeBSD__)
+    if (0 > extattr_set_fd(fd, EXTATTR_NAMESPACE_USER, name, buf, buf_len)) {
+        log_printf("extattr_set_fd(): %s", strerror(errno));
+        return -1;
+    }
+#else
+#  error "not implemented"
+#endif
+    return 0;
+}
+
+static char *
+xattr_normalize_name (
+    char const *name
+) {
+    char const *prefix     = XATTR_NAME_PREFIX;
+    size_t      prefix_len = strlen(prefix);
+    size_t      name_len   = strlen(name);
+
+    char *new_name = xmalloc(prefix_len + name_len + 1);
+    memcpy(new_name, prefix, prefix_len);
+    memcpy(new_name + prefix_len, name, name_len + 1);
+    return new_name;
+}
+
+int
+bookmarkfs_xattr_get (
+    int                  fd,
+    char const          *name,
+    bookmarkfs_xattr_cb *callback,
+    void                *user_data
+) {
+    char *real_name = xattr_normalize_name(name);
+    void *buf = NULL;
+    ssize_t result;
+    do {
+        result = xattr_do_get(fd, real_name, NULL, 0);
+        if (result < 0) {
+            break;
+        }
+
+        buf = xrealloc(buf, result);
+        result = xattr_do_get(fd, real_name, buf, result);
+        if (unlikely(result < 0)) {
+            if (result == -ERANGE) {
+                continue;
+            }
+            break;
+        }
+
+        result = callback(user_data, buf, result);
+    } while (0);
+
+    free(real_name);
+    free(buf);
+    return result;
+}
+
+int
+bookmarkfs_xattr_list (
+    int                  fd,
+    bookmarkfs_xattr_cb *callback,
+    void                *user_data
+) {
+    char *buf = NULL;
+    ssize_t result;
+    do {
+        result = xattr_do_list(fd, NULL, 0);
+        if (result < 0) {
+            goto end;
+        }
+
+        buf = xrealloc(buf, result);
+        result = xattr_do_list(fd, buf, result);
+        if (unlikely(result < 0)) {
+            if (result == -ERANGE) {
+                continue;
+            }
+            goto end;
+        }
+    } while (0);
+
+    char const *prefix     = XATTR_NAME_PREFIX;
+    size_t      prefix_len = strlen(prefix);
+    for (char *curr = buf, *end = curr + result; curr < end; ) {
+        char   *name;
+        size_t  name_len;
+#if defined(__linux__)
+        name     = curr;
+        name_len = strlen(name);
+        curr += name_len + 1;
+#elif defined(__FreeBSD__)
+        name_len = (unsigned char)(*(curr++));
+        name     = curr;
+        curr += name_len;
+#else
+#  error "not implemented"
+#endif
+        if (name_len <= prefix_len || 0 != memcmp(prefix, name, prefix_len)) {
+            continue;
+        }
+        result = callback(user_data, name + prefix_len, name_len - prefix_len);
+        if (result != 0) {
+            goto end;
+        }
+    }
+
+  end:
+    free(buf);
+    return result;
+}
+
+int
+bookmarkfs_xattr_open (
+    char const *path
+) {
+    int flags = O_RDONLY;
+#if defined(__FreeBSD__)
+    // Linux does not accept O_PATH fd for f*xattr() calls.
+    flags |= O_PATH;
+#endif
+    int fd = open(path, flags);
+    if (fd < 0) {
+        log_printf("open(): %s: %s", path, strerror(errno));
+        return -1;
+    }
+    return fd;
+}
+
+int
+bookmarkfs_xattr_set (
+    int         fd,
+    char const *name,
+    void const *buf,
+    size_t      buf_len
+) {
+    char *real_name = xattr_normalize_name(name);
+    int status = xattr_do_set(fd, real_name, buf, buf_len);
+    free(real_name);
+    return status;
+}

src/xattr.h

@@ -0,0 +1,62 @@
+/**
+ * bookmarkfs/src/xattr.h
+ * ----
+ *
+ * Copyright (C) 2025  CismonX <admin@cismon.net>
+ *
+ * This file is part of BookmarkFS.
+ *
+ * BookmarkFS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * BookmarkFS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with BookmarkFS.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef BOOKMARKFS_XATTR_H_
+#define BOOKMARKFS_XATTR_H_
+
+#include <stddef.h>
+
+typedef int (bookmarkfs_xattr_cb) (
+    void   *user_data,
+    void   *buf,
+    size_t  buf_len
+);
+
+int
+bookmarkfs_xattr_get (
+    int                  fd,
+    char const          *name,
+    bookmarkfs_xattr_cb *callback,
+    void                *user_data
+);
+
+int
+bookmarkfs_xattr_list (
+    int                  fd,
+    bookmarkfs_xattr_cb *callback,
+    void                *user_data
+);
+
+int
+bookmarkfs_xattr_open (
+    char const *path
+);
+
+int
+bookmarkfs_xattr_set (
+    int         fd,
+    char const *name,
+    void const *buf,
+    size_t      buf_len
+);
+
+#endif  /* !defined(BOOKMARKFS_XATTR_H_) */