miscutils/getfattr.c

   1 /*
   2  * getfattr - get extended attributes of filesystem objects.
   3  *
   4  * Copyright (C) 2023 by LoveSy <lovesykun@gmail.com>
   5  *
   6  * Licensed under GPLv2, see file LICENSE in this source tree.
   7  */
   8 //config:config GETFATTR
   9 //config:       bool "getfattr (12.3 kb)"
  10 //config:       default y
  11 //config:       help
  12 //config:       Get extended attributes on files
  13
  14 //applet:IF_GETFATTR(APPLET_NOEXEC(getfattr, getfattr, BB_DIR_USR_BIN, BB_SUID_DROP, getfattr))
  15
  16 //kbuild:lib-$(CONFIG_GETFATTR) += getfattr.o
  17
  18 #include <stdio.h>
  19 #include <sys/xattr.h>
  20 #include "libbb.h"
  21
  22 //usage:#define getfattr_trivial_usage
  23 //usage:       "[-h] {-d|-n ATTR} FILE...\n"
  24 //usage:#define getfattr_full_usage "\n\n"
  25 //usage:       "Get extended attributes"
  26 //usage:     "\n"
  27 //usage:     "\n        -h              Do not follow symlinks"
  28 //usage:     "\n        -d              Dump all attributes"
  29 //usage:     "\n        -n ATTR         Get attribute ATTR"
  30
  31 enum {
  32         OPT_h = (1 << 0),
  33         OPT_d = (1 << 1),
  34         OPT_n = (1 << 2),
  35 };
  36
  37 static int print_attr(const char *file, const char *name, char **buf, size_t *bufsize)
  38 {
  39         ssize_t len;
  40
  41         if (*bufsize == 0)
  42                 goto grow;
  43  again:
  44         len = ((option_mask32 &  OPT_h) ? lgetxattr: getxattr)(file, name, *buf, *bufsize);
  45         if (len < 0) {
  46                 if (errno != ERANGE)
  47                         return len;
  48  grow:
  49                 *bufsize = (*bufsize * 2) + 1024;
  50                 *buf = xrealloc(*buf, *bufsize);
  51                 goto again;
  52         }
  53         printf("%s=\"%.*s\"\n", name, len, *buf);
  54         return 0;
  55 }
  56
  57 static ssize_t list_attr(const char *file, char **list, size_t *listsize)
  58 {
  59         ssize_t len;
  60
  61         if (*listsize == 0)
  62                 goto grow;
  63  again:
  64         len = ((option_mask32 &  OPT_h) ? llistxattr : listxattr)(file, *list, *listsize);
  65         if (len < 0) {
  66                 if (errno != ERANGE)
  67                         return len;
  68  grow:
  69                 *listsize = (*listsize * 2) + 1024;
  70                 *list = xrealloc(*list, *listsize);
  71                 goto again;
  72         }
  73         return len;
  74 }
  75
  76 int getfattr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  77 int getfattr_main(int argc UNUSED_PARAM, char **argv)
  78 {
  79         const char *name;
  80         exitcode_t status;
  81         int opt;
  82         char *buf = NULL;
  83         size_t bufsize = 0;
  84         char *list = NULL;
  85         size_t listsize = 0;
  86
  87         opt = getopt32(argv, "^"
  88                 "hdn:"
  89                 /* Min one arg; -d and -n are exclusive */
  90                 "\0" "-1:n--d:d--n"
  91                         //getfattr 2.5.1 does not enforce this: ":d:n" /* exactly one of -n or -d is required */
  92                 , &name
  93         );
  94         argv += optind;
  95         status = EXIT_SUCCESS;
  96
  97         do {
  98                 int r;
  99 //getfattr 2.5.1 with no -n/-d defaults to -d
 100                 if (!(opt & OPT_n)) {
 101                         ssize_t len = list_attr(*argv, &list, &listsize);
 102                         if (len < 0)
 103                                 goto err;
 104                         if (len > 0) {
 105                                 char *key;
 106                                 printf("# file: %s\n", *argv);
 107                                 key = list;
 108                                 while (len > 0) {
 109                                         ssize_t keylen;
 110                                         r = print_attr(*argv, key, &buf, &bufsize);
 111                                         if (r)
 112                                                 goto err;
 113                                         keylen = strlen(key) + 1;
 114                                         key += keylen;
 115                                         len -= keylen;
 116                                 }
 117                                 bb_putchar('\n');
 118                         }
 119                 } else {
 120                         printf("# file: %s\n", *argv);
 121                         r = print_attr(*argv, name, &buf, &bufsize);
 122                         if (r) {
 123  err:
 124                                 bb_simple_perror_msg(*argv);
 125                                 status = EXIT_FAILURE;
 126                                 continue;
 127                         }
 128                         bb_putchar('\n');
 129                 }
 130         } while (*++argv);
 131
 132         if (ENABLE_FEATURE_CLEAN_UP)
 133                 free(buf);
 134
 135         fflush_stdout_and_exit(status);
 136 }