[PATCH] getfattr: new applet

[余生与君]

Gentle ping.

On Sun, Jun 18, 2023 at 4:53 PM LoveSy <lovesykun at gmail.com> wrote:
>
> function                                             old     new   delta
> getfattr_main                                          -     380    +380
> print_attr                                             -     204    +204
> list_attr                                              -     152    +152
> .rodata                                            95358   95401     +43
> applet_names                                        2766    2775      +9
> e843419 at 0048_000003ed_14                               -       8      +8
> e843419 at 0047_000003d1_550                              -       8      +8
> applet_main                                         3216    3224      +8
> packed_usage                                       34560   34567      +7
> applet_install_loc                                   201     202      +1
> ------------------------------------------------------------------------------
> (add/remove: 6/0 grow/shrink: 5/0 up/down: 820/0)             Total: 820 bytes
>    text    data     bss     dec     hex filename
> 1127717   16889    1736 1146342  117de6 busybox_old
> 1141124   16937    1736 1159797  11b275 busybox_unstripped
>
> Signed-off-by: LoveSy <lovesykun at gmail.com>
> ---
>  miscutils/getfattr.c | 122 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 122 insertions(+)
>  create mode 100644 miscutils/getfattr.c
>
> diff --git a/miscutils/getfattr.c b/miscutils/getfattr.c
> new file mode 100644
> index 000000000..4d4eacb5f
> --- /dev/null
> +++ b/miscutils/getfattr.c
> @@ -0,0 +1,122 @@
> +/*
> + * getfattr - get extended attributes of filesystem objects.
> + *
> + * Copyright (C) 2023 by LoveSy <lovesykun at gmail.com>
> + *
> + * Licensed under GPLv2, see file LICENSE in this source tree.
> + */
> +//config:config GETFATTR
> +//config:      bool "getfattr (12.3 kb)"
> +//config:      default y
> +//config:      help
> +//config:      Get extended attributes on files
> +
> +//applet:IF_GETFATTR(APPLET_NOEXEC(getfattr, getfattr, BB_DIR_USR_BIN, BB_SUID_DROP, getfattr))
> +
> +//kbuild:lib-$(CONFIG_GETFATTR) += getfattr.o
> +
> +#include <stdio.h>
> +#include <sys/xattr.h>
> +#include "libbb.h"
> +
> +//usage:#define getfattr_trivial_usage
> +//usage:       "[-h] -n|-d ATTR FILE..."
> +//usage:#define getfattr_full_usage "\n\n"
> +//usage:       "Get extended attributes"
> +//usage:     "\n"
> +//usage:     "\n       -h              Do not follow symlinks"
> +//usage:     "\n       -d              Dump all attributes"
> +//usage:     "\n       -n ATTR         Get attribute ATTR"
> +int getfattr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
> +
> +int print_attr(const char *file, const char *name, int follow, char **buf, size_t *buflen)
> +{
> +       ssize_t vallen, gotlen;
> +       vallen = (follow ? getxattr: lgetxattr)(file, name, NULL, 0);
> +       if (vallen == -1) {
> +               return -1;
> +       }
> +       vallen += 1;
> +       if (*buflen < vallen) {
> +               *buf = (char *)xrealloc(*buf, vallen);
> +               *buflen = vallen;
> +       }
> +       vallen = (follow ? getxattr : lgetxattr)(file, name, *buf, vallen);
> +       if (vallen == -1) {
> +               return -1;
> +       }
> +       (*buf)[vallen] = '\0';
> +       printf("%s=\"%s\"\n", name, *buf);
> +       return 0;
> +}
> +
> +ssize_t list_attr(const char *file, int follow, char **list, size_t *listlen)
> +{
> +       ssize_t len;
> +       len = (follow ? listxattr : llistxattr)(file, NULL, 0);
> +       if (len == -1) {
> +               return -1;
> +       }
> +       if (*listlen < len) {
> +               *list = (char *)xrealloc(*list, len);
> +               *listlen = len;
> +       }
> +       len = (follow ? listxattr : llistxattr)(file, *list, len);
> +       if (len == -1) {
> +               return -1;
> +       }
> +       return len;
> +}
> +
> +int getfattr_main(int argc UNUSED_PARAM, char **argv)
> +{
> +       const char *name = NULL;
> +       int status;
> +       int opt;
> +       char *buf = NULL;
> +       size_t buflen = 0;
> +       char *list = NULL;
> +       size_t listlen = 0;
> +       enum {
> +               OPT_h = (1 << 0),
> +               OPT_d = (1 << 1),
> +       };
> +
> +       opt = getopt32(argv, "^"
> +               "hdn:"
> +               /* Min one arg, either -x or -n is a must, -d does not allow -n */
> +               "\0" "-1:dn:n--d:d--n"
> +               , &name
> +       );
> +       argv += optind;
> +       status = EXIT_SUCCESS;
> +
> +       do {
> +               int r = 0;
> +               printf("# file: %s\n", *argv);
> +               if (opt & OPT_d) {
> +                       ssize_t len = list_attr(*argv, !(opt & OPT_h), &list, &listlen);
> +                       ssize_t keylen;
> +                       char *key = list;
> +                       while (len > 0 && !r) {
> +                               r = print_attr(*argv, key, !(opt & OPT_h), &buf, &buflen);
> +                               keylen = strlen(key) + 1;
> +                               key += keylen;
> +                               len -= keylen;
> +                       }
> +               }
> +               else {
> +                       r = print_attr(*argv, name, !(opt & OPT_h), &buf, &buflen);
> +               }
> +               printf("\n");
> +
> +               if (r) {
> +                       bb_simple_perror_msg(*argv);
> +                       status = EXIT_FAILURE;
> +               }
> +       } while (*++argv);
> +
> +       free(buf);
> +
> +       return status;
> +}
> --
> 2.34.1
>