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bin/ksh: add bash-like expand-tilde option
As I said previously, I'm happy with this.
Kirill A. Korinsky <kirill@korins.ky> wrote:
> On Sun, 26 Apr 2026 02:59:48 +0200,
> Kirill A. Korinsky <kirill@korins.ky> wrote:
> >
> > On Sat, 25 Apr 2026 12:21:39 +0200,
> > Theo de Raadt <deraadt@cvs.openbsd.org> wrote:
> > >
> > > I am going to argue that the existing behaviour of converting ~username
> > > to the expanded form immediately is a TOCTOU. It works like this:
> > >
> > > 1. user types a partial command with some ~otheruser form that gets expanded,
> > > but does not complete the command yet
> > >
> > > 2. In a different session, root changes that otheruser's homedir or even
> > > deletes the user
> > >
> > > 3. The original user completes their command and types <return>
> > >
> > > What happens next is an action that depended on incorrect early conversion.
> > > An expansion of ~otheru into ~otheruser is one thing which needs to be done
> > > immediately, but the translation into correct pw_dir could be done as a seperate
> > > step. I guess it is a question of whether atomic single-lookup is desireable,
> > > or if reaching the correct user->pw_dir is better.
> > >
> > > The visual improvement of keeping it in ~ format since that is what the user
> > > typed and avoids surprise, makes me prefer always keeping this in ~ visual
> > > format.
> > >
> > > I really dislike optional code which people will or won't use.
> >
> > I never thought about that use case, but it make perfect sense.
> >
> > Here updated diff which:
> >
> > 1. Keep leading tilde expressions in the command line after file completion.
> > Expanding ~user to pw_dir during editing bakes the result of an early
> > passwd lookup into the command line.
> >
> > 2. Complete bare ~user prefixes from the passwd database, so ~us[TAB] can
> > become ~user before pathname completion continues.
> >
> > What makes ksh behaviour similar with bash, zsh and I think fish out of the
> > box without a way to disable it.
> >
> > I had tested it in different inputs which includes things like "~ro[TAB] and
> > it works well enough to be shared and asked for tests and thoughts.
> >
> >
>
> Anyone interesting in this?
>
> Index: bin/ksh/edit.c
> ===================================================================
> RCS file: /home/cvs/src/bin/ksh/edit.c,v
> diff -u -p -r1.71 edit.c
> --- bin/ksh/edit.c 23 Apr 2024 13:34:50 -0000 1.71
> +++ bin/ksh/edit.c 26 Apr 2026 00:41:54 -0000
> @@ -12,6 +12,7 @@
>
> #include <ctype.h>
> #include <errno.h>
> +#include <pwd.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <string.h>
> @@ -27,9 +28,14 @@ static void x_sigwinch(int);
> volatile sig_atomic_t got_sigwinch;
> static void check_sigwinch(void);
>
> -static int x_file_glob(int, const char *, int, char ***);
> +static int x_file_glob(int, const char *, int, char ***, int);
> +static char *x_tilde_expand(const char *);
> +static int x_tilde_is_dir(const char *, int);
> +static int x_tilde_glob(const char *, int, char ***);
> +static const char *x_tilde_name(const char *);
> static int x_command_glob(int, const char *, int, char ***);
> static int x_locate_word(const char *, int, int, int *, int *);
> +static void x_preserve_tilde(char **, int, const char *, const char *);
>
>
> /* Called from main */
> @@ -402,6 +408,139 @@ x_print_expansions(int nwords, char *con
> pr_list(words);
> }
>
> +static char *
> +x_tilde_expand(const char *tilde)
> +{
> + struct passwd *pw;
> + struct tbl *tp;
> + char *dp;
> +
> + if (tilde[0] != '~')
> + return NULL;
> + if (tilde[1] == '\0')
> + dp = str_val(global("HOME"));
> + else if (tilde[1] == '+' && tilde[2] == '\0')
> + dp = str_val(global("PWD"));
> + else if (tilde[1] == '-' && tilde[2] == '\0')
> + dp = str_val(global("OLDPWD"));
> + else {
> + tp = ktsearch(&homedirs, tilde + 1, hash(tilde + 1));
> + if (tp != NULL && (tp->flag & ISSET))
> + dp = tp->val.s;
> + else if ((pw = getpwnam(tilde + 1)) != NULL)
> + dp = pw->pw_dir;
> + else
> + dp = NULL;
> + }
> + if (dp == null || dp == NULL || dp[0] == '~')
> + return NULL;
> + return str_save(dp, ATEMP);
> +}
> +
> +static int
> +x_tilde_is_dir(const char *tilde, int len)
> +{
> + struct stat statb;
> + char *expanded, *copy;
> + int isdir;
> +
> + copy = str_nsave(tilde, len, ATEMP);
> + expanded = x_tilde_expand(copy);
> + afree(copy, ATEMP);
> + if (expanded == NULL)
> + return 0;
> + isdir = stat(expanded, &statb) == 0 && S_ISDIR(statb.st_mode);
> + afree(expanded, ATEMP);
> +
> + return isdir;
> +}
> +
> +static int
> +x_tilde_glob(const char *str, int slen, char ***wordsp)
> +{
> + struct passwd *pw;
> + const char *prefix;
> + char *word;
> + size_t len, prefix_len;
> + int i, nwords;
> + XPtrV w;
> +
> + if (slen < 2 || str[0] != '~')
> + return 0;
> + if (str[1] == '+' || str[1] == '-')
> + return 0;
> + for (i = 1; i < slen; i++) {
> + if (str[i] == '/')
> + return 0;
> + if (str[i] == '\\' || str[i] == '*' || str[i] == '?' ||
> + str[i] == '[' || str[i] == '$')
> + return 0;
> + }
> +
> + prefix = str + 1;
> + prefix_len = slen - 1;
> +
> + XPinit(w, 32);
> + setpwent();
> + while ((pw = getpwent()) != NULL) {
> + if (strncmp(pw->pw_name, prefix, prefix_len) != 0)
> + continue;
> + len = strlen(pw->pw_name);
> + word = areallocarray(NULL, len + 2, sizeof(char), ATEMP);
> + word[0] = '~';
> + memcpy(word + 1, pw->pw_name, len + 1);
> + XPput(w, word);
> + }
> + endpwent();
> +
> + nwords = XPsize(w);
> + if (nwords == 0) {
> + XPfree(w);
> + return 0;
> + }
> + if (nwords == 1 && x_tilde_is_dir(str, slen)) {
> + afree(XPptrv(w)[0], ATEMP);
> + XPfree(w);
> + return 0;
> + }
> +
> + qsortp(XPptrv(w), (size_t)nwords, xstrcmp);
> + XPput(w, NULL);
> + *wordsp = (char **)XPclose(w);
> +
> + return nwords;
> +}
> +
> +static const char *
> +x_tilde_name(const char *tilde)
> +{
> + if (tilde[0] != '~' || tilde[1] == '\0')
> + return NULL;
> + if ((tilde[1] == '+' || tilde[1] == '-') && tilde[2] == '\0')
> + return NULL;
> + return tilde + 1;
> +}
> +
> +int
> +x_is_tilde_user_completion(const char *str, int slen, const char *word,
> + int wlen)
> +{
> + int i;
> +
> + if (slen < 2 || wlen <= slen || str[0] != '~' ||
> + word[0] != '~')
> + return 0;
> + if (strncmp(str, word, slen) != 0)
> + return 0;
> + for (i = 1; i < slen; i++)
> + if (str[i] == '/')
> + return 0;
> + for (i = 1; i < wlen; i++)
> + if (word[i] == '/')
> + return 0;
> + return 1;
> +}
> +
> /*
> * Do file globbing:
> * - appends * to (copy of) str if no globbing chars found
> @@ -410,17 +549,42 @@ x_print_expansions(int nwords, char *con
> * - returns number of matching strings
> */
> static int
> -x_file_glob(int flags, const char *str, int slen, char ***wordsp)
> +x_file_glob(int flags, const char *str, int slen, char ***wordsp,
> + int preserve_tilde)
> {
> char *toglob;
> char **words;
> int nwords;
> XPtrV w;
> struct source *s, *sold;
> + struct tbl *tp;
> + char *tilde = NULL;
> + char *tilde_expanded = NULL;
> + const char *tilde_name = NULL;
> + int tilde_cached = 0;
> + int tlen = 0;
>
> if (slen < 0)
> return 0;
>
> + nwords = x_tilde_glob(str, slen, wordsp);
> + if (nwords)
> + return nwords;
> +
> + if (slen > 0 && str[0] == '~') {
> + for (tlen = 1; tlen < slen; tlen++)
> + if (str[tlen] == '/')
> + break;
> + tilde = str_nsave(str, tlen, ATEMP);
> + tilde_name = x_tilde_name(tilde);
> + if (tilde_name != NULL) {
> + tp = ktsearch(&homedirs, tilde_name,
> + hash(tilde_name));
> + if (tp != NULL && (tp->flag & ISSET))
> + tilde_cached = 1;
> + }
> + }
> +
> toglob = add_glob(str, slen);
>
> /*
> @@ -433,7 +597,9 @@ x_file_glob(int flags, const char *str,
> if (yylex(ONEWORD|UNESCAPE) != LWORD) {
> source = sold;
> internal_warningf("%s: substitute error", __func__);
> - return 0;
> + afree(toglob, ATEMP);
> + nwords = 0;
> + goto done;
> }
> source = sold;
> XPinit(w, 32);
> @@ -461,15 +627,67 @@ x_file_glob(int flags, const char *str,
> afree(toglob, ATEMP);
>
> if (nwords) {
> + if (preserve_tilde && tilde != NULL &&
> + (tilde_expanded = x_tilde_expand(tilde)) != NULL)
> + x_preserve_tilde(words, nwords, tilde,
> + tilde_expanded);
> *wordsp = words;
> } else if (words) {
> x_free_words(nwords, words);
> *wordsp = NULL;
> }
> +done:
> + if (tilde_name != NULL && !tilde_cached) {
> + /* Do not let completion cache the home directory. */
> + tp = ktsearch(&homedirs, tilde_name, hash(tilde_name));
> + if (tp != NULL) {
> + if (tp->flag & ALLOC) {
> + tp->flag &= ~(ALLOC|ISSET);
> + afree(tp->val.s, APERM);
> + }
> + ktdelete(tp);
> + }
> + }
> + if (tilde)
> + afree(tilde, ATEMP);
> + if (tilde_expanded)
> + afree(tilde_expanded, ATEMP);
>
> return nwords;
> }
>
> +static void
> +x_preserve_tilde(char **words, int nwords, const char *tilde,
> + const char *tilde_expanded)
> +{
> + size_t tilde_len, exp_len;
> + int i;
> +
> + tilde_len = strlen(tilde);
> + exp_len = strlen(tilde_expanded);
> + if (exp_len == 0)
> + return;
> +
> + for (i = 0; i < nwords; i++) {
> + char *w = words[i];
> + size_t rest_len;
> + char *nw;
> +
> + if (strncmp(w, tilde_expanded, exp_len) != 0)
> + continue;
> + if (w[exp_len] != '\0' && w[exp_len] != '/')
> + continue;
> +
> + rest_len = strlen(w + exp_len);
> + nw = areallocarray(NULL, tilde_len + rest_len + 1,
> + sizeof(char), ATEMP);
> + memcpy(nw, tilde, tilde_len);
> + memcpy(nw + tilde_len, w + exp_len, rest_len + 1);
> + afree(w, ATEMP);
> + words[i] = nw;
> + }
> +}
> +
> /* Data structure used in x_command_glob() */
> struct path_order_info {
> char *word;
> @@ -721,10 +939,12 @@ x_cf_glob(int flags, const char *buf, in
> int nwords;
> char **words = NULL;
> int is_command;
> + int preserve_tilde;
>
> len = x_locate_word(buf, buflen, pos, startp, &is_command);
> if (!(flags & XCF_COMMAND))
> is_command = 0;
> + preserve_tilde = len > 0 && buf[*startp] == '~';
> /* Don't do command globing on zero length strings - it takes too
> * long and isn't very useful. File globs are more likely to be
> * useful, so allow these.
> @@ -732,10 +952,20 @@ x_cf_glob(int flags, const char *buf, in
> if (len == 0 && is_command)
> return 0;
>
> - if (is_command)
> + if (is_command && (flags & XCF_FILE) && len > 0 &&
> + buf[*startp] == '~') {
> + nwords = x_file_glob(flags, buf + *startp, len, &words,
> + preserve_tilde);
> + if (nwords == 0)
> + nwords = x_command_glob(flags, buf + *startp, len,
> + &words);
> + else
> + is_command = 0;
> + } else if (is_command)
> nwords = x_command_glob(flags, buf + *startp, len, &words);
> else if (!x_try_array(buf, buflen, buf + *startp, len, &nwords, &words))
> - nwords = x_file_glob(flags, buf + *startp, len, &words);
> + nwords = x_file_glob(flags, buf + *startp, len, &words,
> + preserve_tilde);
> if (nwords == 0) {
> *wordsp = NULL;
> return 0;
> @@ -762,14 +992,15 @@ add_glob(const char *str, int slen)
> if (slen < 0)
> return NULL;
>
> - toglob = str_nsave(str, slen + 1, ATEMP); /* + 1 for "*" */
> + toglob = str_nsave(str, slen + 1, ATEMP); /* + 1 for "*" or "/" */
> toglob[slen] = '\0';
>
> /*
> * If the pathname contains a wildcard (an unquoted '*',
> * '?', or '[') or parameter expansion ('$'), or a ~username
> * with no trailing slash, then it is globbed based on that
> - * value (i.e., without the appended '*').
> + * value. Existing tilde directories get a slash appended
> + * instead of '*'; other tilde forms are left exact.
> */
> for (s = toglob; *s; s++) {
> if (*s == '\\' && s[1])
> @@ -780,9 +1011,14 @@ add_glob(const char *str, int slen)
> else if (*s == '/')
> saw_slash = true;
> }
> - if (!*s && (*toglob != '~' || saw_slash)) {
> - toglob[slen] = '*';
> - toglob[slen + 1] = '\0';
> + if (!*s) {
> + if (*toglob != '~' || saw_slash) {
> + toglob[slen] = '*';
> + toglob[slen + 1] = '\0';
> + } else if (x_tilde_is_dir(toglob, slen)) {
> + toglob[slen] = '/';
> + toglob[slen + 1] = '\0';
> + }
> }
>
> return toglob;
> Index: bin/ksh/edit.h
> ===================================================================
> RCS file: /home/cvs/src/bin/ksh/edit.h,v
> diff -u -p -r1.13 edit.h
> --- bin/ksh/edit.h 21 Jun 2023 22:22:08 -0000 1.13
> +++ bin/ksh/edit.h 26 Apr 2026 00:41:54 -0000
> @@ -48,6 +48,7 @@ int promptlen(const char *, const char *
> int x_do_comment(char *, int, int *);
> void x_print_expansions(int, char *const *, int);
> int x_cf_glob(int, const char *, int, int, int *, int *, char ***, int *);
> +int x_is_tilde_user_completion(const char *, int, const char *, int);
> int x_longest_prefix(int , char *const *);
> int x_basename(const char *, const char *);
> void x_free_words(int, char **);
> Index: bin/ksh/emacs.c
> ===================================================================
> RCS file: /home/cvs/src/bin/ksh/emacs.c,v
> diff -u -p -r1.91 emacs.c
> --- bin/ksh/emacs.c 5 Mar 2026 05:38:58 -0000 1.91
> +++ bin/ksh/emacs.c 26 Apr 2026 00:41:54 -0000
> @@ -1767,7 +1767,9 @@ do_complete(int flags, /* XCF_{COMMAND,F
> completed = 1;
> }
> /* add space if single non-dir match */
> - if (nwords == 1 && words[0][nlen - 1] != '/') {
> + if (nwords == 1 && words[0][nlen - 1] != '/' &&
> + !x_is_tilde_user_completion(xbuf + start, olen, words[0],
> + nlen)) {
> x_ins(" ");
> completed = 1;
> }
> Index: bin/ksh/vi.c
> ===================================================================
> RCS file: /home/cvs/src/bin/ksh/vi.c,v
> diff -u -p -r1.69 vi.c
> --- bin/ksh/vi.c 4 Apr 2026 09:33:18 -0000 1.69
> +++ bin/ksh/vi.c 26 Apr 2026 00:41:54 -0000
> @@ -2206,7 +2206,9 @@ complete_word(int command, int count)
> expanded = NONE;
>
> /* If not a directory, add a space to the end... */
> - if (match_len > 0 && match[match_len - 1] != '/')
> + if (match_len > 0 && match[match_len - 1] != '/' &&
> + !x_is_tilde_user_completion(es->cbuf + start,
> + end - start, match, match_len))
> rval = putbuf(" ", 1, 0);
> }
> x_free_words(nwords, words);
>
>
>
> --
> wbr, Kirill
>
bin/ksh: add bash-like expand-tilde option