findmnt: add --list-columns

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/bash-completion/findmnt b/bash-completion/findmnt
index 7270d3616cf057f6ef1bac439dd64d787b0a871f..c8a204c66d3017ae00f17f08dfbc22888aa53ca4 100644 (file)
--- a/bash-completion/findmnt
+++ b/bash-completion/findmnt
@@ -131,6 +131,7 @@ _findmnt_module()
                                --tree
                                --real
                                --pseudo
+                               --list-columns
                                --version"
                        COMPREPLY=( $(compgen -W "${OPTS[*]}" -- $cur) )
                        return 0

diff --git a/misc-utils/findmnt.8.adoc b/misc-utils/findmnt.8.adoc
index 72a1ecf2a2f74eb05b19873c4daac6d4d344627f..5f9e2208d83c4e83698bcfb9e612349fbc137cfe 100644 (file)
--- a/misc-utils/findmnt.8.adoc
+++ b/misc-utils/findmnt.8.adoc
@@ -66,6 +66,9 @@ Search in an alternative file. If used with *--fstab*, *--mtab* or *--kernel*, t
 *-f*, *--first-only*::
 Print the first matching filesystem only.
 
+*-H*, *--list-columns*::
+List the available columns, use with *--json* or *--raw* to get output in machine-readable format.
+
 *-i*, *--invert*::
 Invert the sense of matching.
 

diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index 24e99405d905f57787f7e94be20f7b4d14a28b3d..40b80b36553104df487724734d49ebb7b17c0ac1 100644 (file)
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -48,6 +48,7 @@
 #include "optutils.h"
 #include "mangle.h"
 #include "buffer.h"
+#include "column-list-table.h"
 
 #include "findmnt.h"
 
@@ -101,7 +102,7 @@ struct colinfo {
 /* columns descriptions (don't use const, this is writable) */
 static struct colinfo infos[] = {
        [COL_ACTION]       = { "ACTION",         10, SCOLS_FL_STRICTWIDTH, N_("action detected by --poll") },
-       [COL_AVAIL]        = { "AVAIL",           5, SCOLS_FL_RIGHT, N_("filesystem size available") },
+       [COL_AVAIL]        = { "AVAIL",           5, SCOLS_FL_RIGHT, N_("filesystem size available, use <number> if --bytes is given") },
        [COL_FREQ]         = { "FREQ",            1, SCOLS_FL_RIGHT, N_("dump(8) period in days [fstab only]") },
        [COL_FSROOT]       = { "FSROOT",       0.25, SCOLS_FL_NOEXTREMES, N_("filesystem root") },
        [COL_FSTYPE]       = { "FSTYPE",       0.10, SCOLS_FL_TRUNC, N_("filesystem type") },
@@ -118,12 +119,12 @@ static struct colinfo infos[] = {
        [COL_PARTUUID]     = { "PARTUUID",       36, 0, N_("partition UUID") },
        [COL_PASSNO]       = { "PASSNO",          1, SCOLS_FL_RIGHT, N_("pass number on parallel fsck(8) [fstab only]") },
        [COL_PROPAGATION]  = { "PROPAGATION",  0.10, 0, N_("VFS propagation flags") },
-       [COL_SIZE]         = { "SIZE",            5, SCOLS_FL_RIGHT, N_("filesystem size") },
+       [COL_SIZE]         = { "SIZE",            5, SCOLS_FL_RIGHT, N_("filesystem size, use <number> if --bytes is given") },
        [COL_SOURCES]      = { "SOURCES",      0.25, SCOLS_FL_WRAP, N_("all possible source devices") },
        [COL_SOURCE]       = { "SOURCE",       0.25, SCOLS_FL_NOEXTREMES, N_("source device") },
        [COL_TARGET]       = { "TARGET",       0.30, SCOLS_FL_TREE| SCOLS_FL_NOEXTREMES, N_("mountpoint") },
        [COL_TID]          = { "TID",             4, SCOLS_FL_RIGHT, N_("task ID") },
-       [COL_USED]         = { "USED",            5, SCOLS_FL_RIGHT, N_("filesystem size used") },
+       [COL_USED]         = { "USED",            5, SCOLS_FL_RIGHT, N_("filesystem size used, use <number> if --bytes is given") },
        [COL_USEPERC]      = { "USE%",            3, SCOLS_FL_RIGHT, N_("filesystem use percentage") },
        [COL_UUID]         = { "UUID",           36, 0, N_("filesystem UUID") },
        [COL_VFS_OPTIONS]  = { "VFS-OPTIONS",  0.20, SCOLS_FL_TRUNC, N_("VFS specific mount options") }
@@ -1332,10 +1333,36 @@ static int uniq_fs_target_cmp(
        return !mnt_fs_match_target(a, mnt_fs_get_target(b), cache);
 }
 
+static int get_column_json_type(int id, int scols_flags, int *multi)
+{
+       switch (id) {
+       case COL_SIZE:
+       case COL_AVAIL:
+       case COL_USED:
+               if (multi)
+                       *multi = 1;
+               if (!(flags & FL_BYTES))
+                       break;
+               /* fallthrough */
+       case COL_ID:
+       case COL_PARENT:
+       case COL_FREQ:
+       case COL_PASSNO:
+       case COL_TID:
+               return SCOLS_JSON_NUMBER;
+
+       default:
+               if (scols_flags & SCOLS_FL_WRAP)
+                       return SCOLS_JSON_ARRAY_STRING;
+               break;
+       }
+
+       return SCOLS_JSON_STRING;       /* default */
+}
+
 static void __attribute__((__noreturn__)) usage(void)
 {
        FILE *out = stdout;
-       size_t i;
 
        fputs(USAGE_HEADER, out);
        fprintf(out, _(
@@ -1376,7 +1403,7 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_(" -N, --task <tid>       use alternative namespace (/proc/<tid>/mountinfo file)\n"), out);
        fputs(_(" -n, --noheadings       don't print column headings\n"), out);
        fputs(_(" -O, --options <list>   limit the set of filesystems by mount options\n"), out);
-       fputs(_(" -o, --output <list>    the output columns to be shown\n"), out);
+       fputs(_(" -o, --output <list>    output columns (see --list-columns)\n"), out);
        fputs(_("     --output-all       output all available columns\n"), out);
        fputs(_(" -P, --pairs            use key=\"value\" output format\n"), out);
        fputs(_("     --pseudo           print only pseudo-filesystems\n"), out);
@@ -1401,23 +1428,45 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_("     --vfs-all          print all VFS options\n"), out);
 
        fputs(USAGE_SEPARATOR, out);
+       fputs(_(" -H, --list-columns     list the available columns\n"), out);
        fprintf(out, USAGE_HELP_OPTIONS(24));
 
-       fputs(USAGE_COLUMNS, out);
-       for (i = 0; i < ARRAY_SIZE(infos); i++)
-               fprintf(out, " %11s  %s\n", infos[i].name, _(infos[i].help));
-
        fprintf(out, USAGE_MAN_TAIL("findmnt(8)"));
 
        exit(EXIT_SUCCESS);
 }
 
+static void __attribute__((__noreturn__)) list_colunms(void)
+{
+       size_t i;
+       struct libscols_table *tb = xcolumn_list_table_new("findmnt-columns", stdout,
+                                               flags & FL_RAW,
+                                               flags & FL_JSON);
+
+       for (i = 0; i < ARRAY_SIZE(infos); i++) {
+               const struct colinfo *ci = &infos[i];
+               int multi = 0;
+               int json = get_column_json_type(i, ci->flags, &multi);
+
+               xcolumn_list_table_append_line(tb, ci->name,
+                       multi ? -1 : json,
+                       multi ? "<string|number>" : NULL,
+                      _(ci->help));
+       }
+
+       scols_print_table(tb);
+       scols_unref_table(tb);
+
+       exit(EXIT_SUCCESS);
+}
+
+
 int main(int argc, char *argv[])
 {
        struct libmnt_table *tb = NULL;
        char **tabfiles = NULL;
        int direction = MNT_ITER_FORWARD;
-       int verify = 0;
+       int verify = 0, collist = 0;
        int c, rc = -1, timeout = -1;
        int ntabfiles = 0, tabtype = 0;
        char *outarg = NULL;
@@ -1480,6 +1529,7 @@ int main(int argc, char *argv[])
                { "pseudo",         no_argument,       NULL, FINDMNT_OPT_PSEUDO  },
                { "vfs-all",        no_argument,       NULL, FINDMNT_OPT_VFS_ALL },
                { "shadowed",       no_argument,       NULL, FINDMNT_OPT_SHADOWED },
+               { "list-columns",   no_argument,       NULL, 'H' },
                { NULL, 0, NULL, 0 }
        };
 
@@ -1506,7 +1556,7 @@ int main(int argc, char *argv[])
        flags |= FL_TREE;
 
        while ((c = getopt_long(argc, argv,
-                               "AabCcDd:ehiJfF:o:O:p::PklmM:nN:rst:uvRS:T:Uw:Vxy",
+                               "AabCcDd:ehiJfF:o:O:p::PklmM:nN:rst:uvRS:T:Uw:VxyH",
                                longopts, NULL)) != -1) {
 
                err_exclusive_options(c, longopts, excl, excl_st);
@@ -1664,6 +1714,10 @@ int main(int argc, char *argv[])
                case FINDMNT_OPT_SHADOWED:
                        flags |= FL_SHADOWED;
                        break;
+
+               case 'H':
+                       collist = 1;
+                       break;
                case 'h':
                        usage();
                case 'V':
@@ -1673,6 +1727,9 @@ int main(int argc, char *argv[])
                }
        }
 
+       if (collist)
+               list_colunms();         /* print end exit */
+
        if (!ncolumns && (flags & FL_DF)) {
                add_column(columns, ncolumns++, COL_SOURCE);
                add_column(columns, ncolumns++, COL_FSTYPE);
@@ -1820,29 +1877,8 @@ int main(int argc, char *argv[])
                                                NULL,
                                                scols_wrapzero_nextchunk,
                                                NULL);
-               if (flags & FL_JSON) {
-                       switch (id) {
-                       case COL_SIZE:
-                       case COL_AVAIL:
-                       case COL_USED:
-                               if (!(flags & FL_BYTES))
-                                       break;
-                               /* fallthrough */
-                       case COL_ID:
-                       case COL_PARENT:
-                       case COL_FREQ:
-                       case COL_PASSNO:
-                       case COL_TID:
-                               scols_column_set_json_type(cl, SCOLS_JSON_NUMBER);
-                               break;
-                       default:
-                               if (fl & SCOLS_FL_WRAP)
-                                       scols_column_set_json_type(cl, SCOLS_JSON_ARRAY_STRING);
-                               else
-                                       scols_column_set_json_type(cl, SCOLS_JSON_STRING);
-                               break;
-                       }
-               }
+               if (flags & FL_JSON)
+                       scols_column_set_json_type(cl, get_column_json_type(id, fl, NULL));
        }
 
        /*