52594: support for POSIX real-time signals with kill and trap

Also add new -L option to kill for a more verbose listing of signals

14 files changed, 249 insertions, 63 deletions

diff --git a/ChangeLog b/ChangeLog
index 684820f92..53038c221 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2024-02-28  Oliver Kiddle  <opk@zsh.org>
+
+	* 52594: Completion/Zsh/Command/_kill, Doc/Zsh/builtins.yo,
+	Doc/Zsh/params.yo, Src/Modules/parameter.c, Src/builtin.c,
+	Src/exec.c, Src/hashtable.c, Src/init.c, Src/jobs.c, Src/params.c,
+	Src/signals.c, Src/signals.h, Src/signames2.awk: support for
+	POSIX real-time signals with kill and trap and add -L option to
+	kill for more verbose listing of signals
+
 2024-02-24  Bart Schaefer  <schaefer@zsh.org>
 
 	* 52597: Src/math.c: fix multibyte and metafied character counts
diff --git a/Completion/Zsh/Command/_kill b/Completion/Zsh/Command/_kill
index 084cf42c8..3b5c02151 100644
--- a/Completion/Zsh/Command/_kill
+++ b/Completion/Zsh/Command/_kill
@@ -4,10 +4,11 @@ local curcontext="$curcontext" line state ret=1
 typeset -A opt_args
 
 _arguments -C \
-  '(-s -l 1)-n[specify signal number]:signal number' \
-  '(-l)-q[send the specified integer with the signal using sigqueue]:value' \
-  '(-n -l 1)-s[specify signal name]:signal:_signals -s' \
-  '(-n -s)-l[list signal names or numbers of specified signals]:*:signal:_signals' \
+  '(-s -l -L 1)-n[specify signal number]:signal number' \
+  '(-l -L)-q[send the specified integer with the signal using sigqueue]:value' \
+  '(-n -l -L 1)-s[specify signal name]:signal:_signals -s' \
+  '-l[list signal names or numbers of specified signals]:*:signal:_signals' \
+  '(- *)-L[list each signal and corresponding number]' \
   '(-n -s -l)1::signal:_signals -p -s' \
   '*:processes:->processes' && ret=0
   
diff --git a/Doc/Zsh/builtins.yo b/Doc/Zsh/builtins.yo
index 784089594..6318053d8 100644
--- a/Doc/Zsh/builtins.yo
+++ b/Doc/Zsh/builtins.yo
@@ -1144,7 +1144,8 @@ cindex(killing jobs)
 cindex(jobs, killing)
 xitem(tt(kill) [ tt(-s) var(signal_name) | tt(-n) var(signal_number) | \
 tt(-)var(sig) ] [ tt(-q) var(value) ] var(job) ...)
-item(tt(kill) tt(-l) [ var(sig) ... ])(
+xitem(tt(kill) tt(-l) [ var(sig) ... ])
+item(tt(kill) tt(-L))(
 Sends either tt(SIGTERM) or the specified signal to the given
 jobs or processes.
 Signals are given by number or by names, with or without the `tt(SIG)'
@@ -1158,7 +1159,8 @@ specified the signal names are listed.  Otherwise, for each
 var(sig) that is a name, the corresponding signal number is
 listed.  For each var(sig) that is a signal number or a number
 representing the exit status of a process which was terminated or
-stopped by a signal the name of the signal is printed.
+stopped by a signal the name of the signal is printed.  The final
+form with tt(-L) lists each signal name with its corresponding number.
 
 On some systems, alternative signal names are allowed for a few signals.
 Typical examples are tt(SIGCHLD) and tt(SIGCLD) or tt(SIGPOLL) and
diff --git a/Doc/Zsh/params.yo b/Doc/Zsh/params.yo
index a6fbe6723..8c5e67e70 100644
--- a/Doc/Zsh/params.yo
+++ b/Doc/Zsh/params.yo
@@ -953,7 +953,10 @@ has index 1, the signals are offset by 1 from the signal number
 used by the operating system.  For example, on typical Unix-like systems
 tt(HUP) is signal number 1, but is referred to as tt($signals[2]).  This
 is because of tt(EXIT) at position 1 in the array, which is used
-internally by zsh but is not known to the operating system.
+internally by zsh but is not known to the operating system. On many systems
+there is a block of reserved or unused signal numbers before the POSIX
+real-time signals so the array index can't be used as an accurate indicator
+of their signal number. Use, for example, tt(kill -l SIGRTMIN) instead.
 )
 vindex(TRY_BLOCK_ERROR)
 item(tt(TRY_BLOCK_ERROR) <S>)(
diff --git a/Src/Modules/parameter.c b/Src/Modules/parameter.c
index a05ea2fe4..7441c30b8 100644
--- a/Src/Modules/parameter.c
+++ b/Src/Modules/parameter.c
@@ -309,7 +309,7 @@ setfunction(char *name, char *val, int dis)
     shfunc_set_sticky(shf);
 
     if (!strncmp(name, "TRAP", 4) &&
-	(sn = getsignum(name + 4)) != -1) {
+	(sn = getsigidx(name + 4)) != -1) {
 	if (settrap(sn, NULL, ZSIG_FUNC)) {
 	    freeeprog(shf->funcdef);
 	    zfree(shf, sizeof(*shf));
diff --git a/Src/builtin.c b/Src/builtin.c
index f72d14da4..44dfed651 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -3425,16 +3425,16 @@ bin_functions(char *name, char **argv, Options ops, int func)
 	    newsh->sticky = sticky_emulation_dup(shf->sticky, 0);
 	/* is newsh a signal trap? (adapted from exec.c) */
 	if (!strncmp(s, "TRAP", 4)) {
-	    int signum = getsignum(s + 4);
-	    if (signum != -1) {
-		if (settrap(signum, NULL, ZSIG_FUNC)) {
+	    int sigidx = getsigidx(s + 4);
+	    if (sigidx != -1) {
+		if (settrap(sigidx, NULL, ZSIG_FUNC)) {
 		    freeeprog(newsh->funcdef);
 		    dircache_set(&newsh->filename, NULL);
 		    zfree(newsh, sizeof(*newsh));
 		    return 1;
 		}
 		/* Remove any old node explicitly */
-		removetrapnode(signum);
+		removetrapnode(sigidx);
 	    }
 	}
 	shfunctab->addnode(shfunctab, ztrdup(s), &newsh->node);
@@ -3713,15 +3713,15 @@ bin_functions(char *name, char **argv, Options ops, int func)
 		/* no flags, so just print */
 		printshfuncexpand(&shf->node, pflags, expand);
 	} else if (on & PM_UNDEFINED) {
-	    int signum = -1, ok = 1;
+	    int sigidx = -1, ok = 1;
 
 	    if (!strncmp(*argv, "TRAP", 4) &&
-		(signum = getsignum(*argv + 4)) != -1) {
+		(sigidx = getsigidx(*argv + 4)) != -1) {
 		/*
 		 * Because of the possibility of alternative names,
 		 * we must remove the trap explicitly.
 		 */
-		removetrapnode(signum);
+		removetrapnode(sigidx);
 	    }
 
 	    if (**argv == '/') {
@@ -3757,8 +3757,8 @@ bin_functions(char *name, char **argv, Options ops, int func)
 	    shfunc_set_sticky(shf);
 	    add_autoload_function(shf, *argv);
 
-	    if (signum != -1) {
-		if (settrap(signum, NULL, ZSIG_FUNC)) {
+	    if (sigidx != -1) {
+		if (settrap(sigidx, NULL, ZSIG_FUNC)) {
 		    shfunctab->removenode(shfunctab, *argv);
 		    shfunctab->freenode(&shf->node);
 		    returnval = 1;
@@ -7346,7 +7346,7 @@ bin_trap(char *name, char **argv, UNUSED(Options ops), UNUSED(int func))
     /* If given no arguments, list all currently-set traps */
     if (!*argv) {
 	queue_signals();
-	for (sig = 0; sig < VSIGCOUNT; sig++) {
+	for (sig = 0; sig < TRAPCOUNT; sig++) {
 	    if (sigtrapped[sig] & ZSIG_FUNC) {
 		HashNode hn;
 
@@ -7372,13 +7372,13 @@ bin_trap(char *name, char **argv, UNUSED(Options ops), UNUSED(int func))
 
     /* If we have a signal number, unset the specified *
      * signals.  With only -, remove all traps.        */
-    if ((getsignum(*argv) != -1) || (!strcmp(*argv, "-") && argv++)) {
+    if ((getsigidx(*argv) != -1) || (!strcmp(*argv, "-") && argv++)) {
 	if (!*argv) {
-	    for (sig = 0; sig < VSIGCOUNT; sig++)
+	    for (sig = 0; sig < TRAPCOUNT; sig++)
 		unsettrap(sig);
 	} else {
 	    for (; *argv; argv++) {
-		sig = getsignum(*argv);
+		sig = getsigidx(*argv);
 		if (sig == -1) {
 		    zwarnnam(name, "undefined signal: %s", *argv);
 		    break;
@@ -7403,12 +7403,12 @@ bin_trap(char *name, char **argv, UNUSED(Options ops), UNUSED(int func))
 	Eprog t;
 	int flags;
 
-	sig = getsignum(*argv);
+	sig = getsigidx(*argv);
 	if (sig == -1) {
 	    zwarnnam(name, "undefined signal: %s", *argv);
 	    break;
 	}
-	if (idigit(**argv) ||
+	if (idigit(**argv) || (sig >= VSIGCOUNT) ||
 	    !strcmp(sigs[sig], *argv) ||
 	    (!strncmp("SIG", *argv, 3) && !strcmp(sigs[sig], *argv+3))) {
 	    /* The signal was specified by number or by canonical name (with
diff --git a/Src/exec.c b/Src/exec.c
index 0750738ce..d85adbea5 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -5427,7 +5427,7 @@ execfuncdef(Estate state, Eprog redir_prog)
 	} else {
 	    /* is this shell function a signal trap? */
 	    if (!strncmp(s, "TRAP", 4) &&
-		(signum = getsignum(s + 4)) != -1) {
+		(signum = getsigidx(s + 4)) != -1) {
 		if (settrap(signum, NULL, ZSIG_FUNC)) {
 		    freeeprog(shf->funcdef);
 		    dircache_set(&shf->filename, NULL);
diff --git a/Src/hashtable.c b/Src/hashtable.c
index bb165505e..75b06c4ad 100644
--- a/Src/hashtable.c
+++ b/Src/hashtable.c
@@ -836,10 +836,10 @@ static HashNode
 removeshfuncnode(UNUSED(HashTable ht), const char *nam)
 {
     HashNode hn;
-    int signum;
+    int sigidx;
 
-    if (!strncmp(nam, "TRAP", 4) && (signum = getsignum(nam + 4)) != -1)
-	hn = removetrap(signum);
+    if (!strncmp(nam, "TRAP", 4) && (sigidx = getsigidx(nam + 4)) != -1)
+	hn = removetrap(sigidx);
     else
 	hn = removehashnode(shfunctab, nam);
 
@@ -856,10 +856,10 @@ disableshfuncnode(HashNode hn, UNUSED(int flags))
 {
     hn->flags |= DISABLED;
     if (!strncmp(hn->nam, "TRAP", 4)) {
-	int signum = getsignum(hn->nam + 4);
-	if (signum != -1) {
-	    sigtrapped[signum] &= ~ZSIG_FUNC;
-	    unsettrap(signum);
+	int sigidx = getsigidx(hn->nam + 4);
+	if (sigidx != -1) {
+	    sigtrapped[sigidx] &= ~ZSIG_FUNC;
+	    unsettrap(sigidx);
 	}
     }
 }
@@ -876,9 +876,9 @@ enableshfuncnode(HashNode hn, UNUSED(int flags))
 
     shf->node.flags &= ~DISABLED;
     if (!strncmp(shf->node.nam, "TRAP", 4)) {
-	int signum = getsignum(shf->node.nam + 4);
-	if (signum != -1) {
-	    settrap(signum, NULL, ZSIG_FUNC);
+	int sigidx = getsigidx(shf->node.nam + 4);
+	if (sigidx != -1) {
+	    settrap(sigidx, NULL, ZSIG_FUNC);
 	}
     }
 }
diff --git a/Src/init.c b/Src/init.c
index 83b79d3d4..ec21521b1 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -1382,6 +1382,9 @@ setupshin(char *runscript)
 void
 init_signals(void)
 {
+    sigtrapped = (int *) hcalloc(TRAPCOUNT * sizeof(int));
+    siglists = (Eprog *) hcalloc(TRAPCOUNT * sizeof(Eprog));
+
     if (interact) {
 	int i;
 	signal_setmask(signal_mask(0));
diff --git a/Src/jobs.c b/Src/jobs.c
index 118c5e61b..49decc661 100644
--- a/Src/jobs.c
+++ b/Src/jobs.c
@@ -1073,6 +1073,21 @@ should_report_time(Job j)
     return 0;
 }
 
+/**/
+char *
+sigmsg(int sig)
+{
+    static char *unknown = "unknown signal";
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    static char rtmsg[] = "real-time event XXX";
+    if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
+	sprintf(rtmsg + sizeof(rtmsg) - 4, "%u", sig - SIGRTMIN + 1);
+	return rtmsg;
+    }
+#endif
+    return sig <= SIGCOUNT ? sig_msg[sig] : unknown;
+}
+
 /* !(lng & 3) means jobs    *
  *  (lng & 1) means jobs -l *
  *  (lng & 2) means jobs -p
@@ -2694,7 +2709,7 @@ static const struct {
 int
 bin_kill(char *nam, char **argv, UNUSED(Options ops), UNUSED(int func))
 {
-    int sig = SIGTERM;
+    int status, sig = SIGTERM;
     int returnval = 0;
 #ifdef HAVE_SIGQUEUE
     union sigval sigqueue_info;
@@ -2740,23 +2755,29 @@ bin_kill(char *nam, char **argv, UNUSED(Options ops), UNUSED(int func))
 	    if ((*argv)[1] == 'l' && (*argv)[2] == '\0') {
 		if (argv[1]) {
 		    while (*++argv) {
-			sig = zstrtol(*argv, &signame, 10);
+			status = zstrtol(*argv, &signame, 10);
 			if (signame == *argv) {
+			    signame = casemodify(signame, CASMOD_UPPER);
 			    if (!strncmp(signame, "SIG", 3))
 				signame += 3;
 			    for (sig = 1; sig <= SIGCOUNT; sig++)
-				if (!strcasecmp(sigs[sig], signame))
+				if (!strcmp(sigs[sig], signame))
 				    break;
 			    if (sig > SIGCOUNT) {
 				int i;
 
 				for (i = 0; alt_sigs[i].name; i++)
-				    if (!strcasecmp(alt_sigs[i].name, signame))
+				    if (!strcmp(alt_sigs[i].name, signame))
 				    {
 					sig = alt_sigs[i].num;
 					break;
 				    }
 			    }
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+			    if (sig > SIGCOUNT && (sig = rtsigno(signame))) {
+				printf("%d\n", sig);
+			    } else
+#endif
 			    if (sig > SIGCOUNT) {
 				zwarnnam(nam, "unknown signal: SIG%s",
 					 signame);
@@ -2769,14 +2790,15 @@ bin_kill(char *nam, char **argv, UNUSED(Options ops), UNUSED(int func))
 					 signame);
 				returnval++;
 			    } else {
-				if (WIFSIGNALED(sig))
-				    sig = WTERMSIG(sig);
-				else if (WIFSTOPPED(sig))
-				    sig = WSTOPSIG(sig);
+				sig = status & ~0200;
 				if (1 <= sig && sig <= SIGCOUNT)
 				    printf("%s\n", sigs[sig]);
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+				else if ((signame = rtsigname(sig, 0)))
+				    printf("%s\n", signame);
+#endif
 				else
-				    printf("%d\n", sig);
+				    printf("%d\n", status);
 			    }
 			}
 		    }
@@ -2785,10 +2807,42 @@ bin_kill(char *nam, char **argv, UNUSED(Options ops), UNUSED(int func))
 		printf("%s", sigs[1]);
 		for (sig = 2; sig <= SIGCOUNT; sig++)
 		    printf(" %s", sigs[sig]);
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+		for (sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
+		    printf(" %s", rtsigname(sig, 0));
+#endif
 		putchar('\n');
 		return 0;
 	    }
 
+	    /* with argument "-L" list signals with their numbers in a table */
+	    if ((*argv)[1] == 'L' && (*argv)[2] == '\0') {
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+		const int width = SIGRTMAX >= 100 ? 3 : 2;
+#else
+		const int width = SIGCOUNT >= 100 ? 3 : 2;
+#endif
+		for (sig = 1; sig < SIGCOUNT
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+			+ 1
+#endif
+			; sig++)
+		{
+		    printf("%*d) %-10s%c", width, sig, sigs[sig],
+			    sig % 5 ? ' ' : '\n');
+		}
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+		for (sig = SIGRTMIN; sig < SIGRTMAX; sig++) {
+		    printf("%*d) %-10s%c", width, sig, rtsigname(sig, 0),
+			    (sig - SIGRTMIN + SIGCOUNT + 1) % 5 ? ' ' : '\n');
+		}
+		printf("%*d) RTMAX\n", width, sig);
+#else
+		printf("%*d) %s\n", width, sig, sigs[sig]);
+#endif
+		return 0;
+	    }
+
     	    if ((*argv)[1] == 'n' && (*argv)[2] == '\0') {
 	    	char *endp;
 
@@ -2833,9 +2887,13 @@ bin_kill(char *nam, char **argv, UNUSED(Options ops), UNUSED(int func))
 			    break;
 			}
 		}
-		if (sig > SIGCOUNT) {
+		if (sig > SIGCOUNT
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+			&& !(sig = rtsigno(signame))
+#endif
+			) {
 		    zwarnnam(nam, "unknown signal: SIG%s", signame);
-		    zwarnnam(nam, "type kill -l for a list of signals");
+		    zwarnnam(nam, "type kill -L for a list of signals");
 		    return 1;
 		}
 	    }
@@ -2916,18 +2974,19 @@ bin_kill(char *nam, char **argv, UNUSED(Options ops), UNUSED(int func))
 
     return returnval < 126 ? returnval : 1;
 }
-/* Get a signal number from a string */
+
+/* Get index into table of traps from a string describing a signal */
 
 /**/
 mod_export int
-getsignum(const char *s)
+getsigidx(const char *s)
 {
     int x, i;
 
     /* check for a signal specified by number */
     x = atoi(s);
-    if (idigit(*s) && x >= 0 && x < VSIGCOUNT)
-	return x;
+    if (idigit(*s) && x >= 0)
+	return SIGIDX(x);
 
     /* search for signal by name */
     if (!strncmp(s, "SIG", 3))
@@ -2943,11 +3002,16 @@ getsignum(const char *s)
 	    return alt_sigs[i].num;
     }
 
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    if ((x = rtsigno(s)))
+	return SIGIDX(x);
+#endif
+
     /* no matching signal */
     return -1;
 }
 
-/* Get the name for a signal. */
+/* Get the name for a signal given the index into the traps table. */
 
 /**/
 mod_export const char *
@@ -2961,6 +3025,11 @@ getsigname(int sig)
 		return alt_sigs[i].name;
     }
     else
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    if (sig >= VSIGCOUNT)
+	return rtsigname(SIGNUM(sig), 0);
+    else
+#endif
 	return sigs[sig];
 
     /* shouldn't reach here */
@@ -2985,10 +3054,22 @@ gettrapnode(int sig, int ignoredisable)
     else
 	getptr = shfunctab->getnode;
 
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    if (sig >= VSIGCOUNT)
+	sprintf(fname, "TRAP%s", rtsigname(SIGNUM(sig), 0));
+    else
+#endif
     sprintf(fname, "TRAP%s", sigs[sig]);
     if ((hn = getptr(shfunctab, fname)))
 	return hn;
 
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    if (sig >= VSIGCOUNT) {
+	sprintf(fname, "TRAP%s", rtsigname(SIGNUM(sig), 1));
+	return getptr(shfunctab, fname);
+    }
+#endif
+
     for (i = 0; alt_sigs[i].name; i++) {
 	if (alt_sigs[i].num == sig) {
 	    sprintf(fname, "TRAP%s", alt_sigs[i].name);
diff --git a/Src/params.c b/Src/params.c
index 225acb8a1..7c5e9d8ff 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -946,8 +946,18 @@ createparamtable(void)
     setsparam("ZSH_ARGZERO", ztrdup(posixzero));
     setsparam("ZSH_VERSION", ztrdup_metafy(ZSH_VERSION));
     setsparam("ZSH_PATCHLEVEL", ztrdup_metafy(ZSH_PATCHLEVEL));
-    setaparam("signals", sigptr = zalloc((SIGCOUNT+4) * sizeof(char *)));
-    for (t = sigs; (*sigptr++ = ztrdup_metafy(*t++)); );
+    setaparam("signals", sigptr = zalloc((TRAPCOUNT + 1) * sizeof(char *)));
+    t = sigs;
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    while (t - sigs <= SIGCOUNT)
+	*sigptr++ = ztrdup_metafy(*t++);
+    {
+	int sig;
+	for (sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
+	    *sigptr++ = ztrdup_metafy(rtsigname(sig, 0));
+    }
+#endif
+    while ((*sigptr++ = ztrdup_metafy(*t++))) /* empty */ ;
 
     noerrs = 0;
 }
diff --git a/Src/signals.c b/Src/signals.c
index b1a843e2c..d28853ea6 100644
--- a/Src/signals.c
+++ b/Src/signals.c
@@ -31,10 +31,12 @@
 #include "signals.pro"
  
 /* Array describing the state of each signal: an element contains *
- * 0 for the default action or some ZSIG_* flags ored together.   */
+ * 0 for the default action or some ZSIG_* flags ored together.   *
+ * Contains TRAPCOUNT elements but can't be allocated statically  *
+ * because that's a dynamic value on Linux                        */
 
 /**/
-mod_export int sigtrapped[VSIGCOUNT];
+mod_export int *sigtrapped;
 
 /*
  * Trap programme lists for each signal.
@@ -48,7 +50,7 @@ mod_export int sigtrapped[VSIGCOUNT];
  */
 
 /**/
-mod_export Eprog siglists[VSIGCOUNT];
+mod_export Eprog *siglists;
 
 /* Total count of trapped signals */
 
@@ -892,7 +894,7 @@ dosavetrap(int sig, int level)
  * Set a trap:  note this does not handle manipulation of
  * the function table for TRAPNAL functions.
  *
- * sig is the signal number.
+ * sig is index into the table of trapped signals.
  *
  * l is the list to be eval'd for a trap defined with the "trap"
  * builtin and should be NULL for a function trap.
@@ -931,6 +933,10 @@ settrap(int sig, Eprog l, int flags)
 #endif
             sig != SIGCHLD)
             signal_ignore(sig);
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+	else if (sig >= VSIGCOUNT && sig < TRAPCOUNT)
+	    signal_ignore(SIGNUM(sig));
+#endif
     } else {
 	nsigtrapped++;
         sigtrapped[sig] = ZSIG_TRAPPED;
@@ -940,6 +946,10 @@ settrap(int sig, Eprog l, int flags)
 #endif
             sig != SIGCHLD)
             install_handler(sig);
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+	if (sig >= VSIGCOUNT && sig < TRAPCOUNT)
+	    install_handler(SIGNUM(sig));
+#endif
     }
     sigtrapped[sig] |= flags;
     /*
@@ -1019,6 +1029,11 @@ removetrap(int sig)
 #endif
              sig != SIGCHLD)
         signal_default(sig);
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+    else if (sig >= VSIGCOUNT && sig < TRAPCOUNT)
+	    signal_default(SIGNUM(sig));
+#endif
+
     if (sig == SIGEXIT)
 	exit_trap_posix = 0;
 
@@ -1172,7 +1187,7 @@ endtrapscope(void)
 static int
 handletrap(int sig)
 {
-    if (!sigtrapped[sig])
+    if (!sigtrapped[SIGIDX(sig)])
 	return 0;
 
     if (trap_queueing_enabled)
@@ -1189,7 +1204,7 @@ handletrap(int sig)
 	return 1;
     }
 
-    dotrap(sig);
+    dotrap(SIGIDX(sig));
 
     if (sig == SIGALRM)
     {
@@ -1481,3 +1496,60 @@ dotrap(int sig)
 
     restore_queue_signals(q);
 }
+
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+
+/* Realtime signals, these are a contiguous block that can
+ * be separated from the other signals with an unused gap. */
+
+/**/
+int
+rtsigno(const char* signame)
+{
+    const int maxofs = SIGRTMAX - SIGRTMIN;
+    const char *end = signame + 5;
+    int offset;
+    struct rtdir { int sig; int dir; char op; } x = { 0, 0, 0 };
+    if (!strncmp(signame, "RTMIN", 5)) {
+	x = (struct rtdir) { SIGRTMIN, 1, '+' };
+    } else if (!strncmp(signame, "RTMAX", 5)) {
+	x = (struct rtdir) { SIGRTMAX, -1, '-' };
+    } else
+	return 0;
+
+    if (signame[5] == x.op) {
+	if ((offset = strtol(signame + 6, (char **) &end, 10)) > maxofs)
+	    return 0;
+	x.sig += offset * x.dir;
+    }
+    if (*end)
+	return 0;
+
+    return x.sig;
+}
+
+/**/
+char *
+rtsigname(int signo, int alt)
+{
+    char* buf = (char *) zhalloc(10);
+    int minofs = signo - SIGRTMIN;
+    int maxofs = SIGRTMAX - signo;
+    int offset;
+    int form = alt ^ (maxofs < minofs);
+
+    if (signo < SIGRTMIN || signo > SIGRTMAX)
+	return NULL;
+
+    strcpy(buf, "RT");
+    strcpy(buf+2, form ? "MAX-" : "MIN+");
+    offset = form ? maxofs : minofs;
+    if (offset) {
+	snprintf(buf + 6, 4, "%d", offset);
+    } else {
+	buf[5] = '\0';
+    }
+    return buf;
+}
+
+#endif
diff --git a/Src/signals.h b/Src/signals.h
index 41ac88cce..391f11fed 100644
--- a/Src/signals.h
+++ b/Src/signals.h
@@ -36,6 +36,15 @@
 #define SIGZERR   (SIGCOUNT+1)
 #define SIGDEBUG  (SIGCOUNT+2)
 #define VSIGCOUNT (SIGCOUNT+3)
+#if defined(SIGRTMIN) && defined(SIGRTMAX)
+# define TRAPCOUNT (VSIGCOUNT + SIGRTMAX - SIGRTMIN + 1)
+# define SIGNUM(x) ((x) >= VSIGCOUNT ? (x) - VSIGCOUNT + SIGRTMIN : (x))
+# define SIGIDX(x) ((x) >= SIGRTMIN && (x) <= SIGRTMAX ? (x) - SIGRTMIN + VSIGCOUNT : (x))
+#else
+# define TRAPCOUNT VSIGCOUNT
+# define SIGNUM(x) (x)
+# define SIGIDX(x) (x)
+#endif
 #define SIGEXIT    0
 
 #ifdef SV_BSDSIG
diff --git a/Src/signames2.awk b/Src/signames2.awk
index 4d1557cd8..5738030c6 100644
--- a/Src/signames2.awk
+++ b/Src/signames2.awk
@@ -15,7 +15,7 @@
     if (signam == "CHLD" && sig[signum] == "CLD")  sig[signum] = ""
     if (signam == "POLL" && sig[signum] == "IO")   sig[signum] = ""
     if (signam == "ABRT" && sig[signum] == "IOT")  sig[signum] = ""
-    if (sig[signum] == "") {
+    if (signam !~ /RTM(IN|AX)/ && sig[signum] == "") {
 	sig[signum] = signam
 	if (0 + max < 0 + signum && signum < 60)
 	    max = signum
@@ -66,10 +66,6 @@ END {
     printf "#include %czsh.mdh%c\n", 34, 34
     printf "\n"
     printf "/**/\n"
-    printf "#define sigmsg(sig) ((sig) <= SIGCOUNT ? sig_msg[sig]"
-    printf " : %c%s%c)", 34, "unknown signal", 34
-    printf "\n"
-    printf "/**/\n"
     printf "mod_export char *sig_msg[SIGCOUNT+2] = {\n"
     printf "\t%c%s%c,\n", 34, "done", 34