ash: add bash-like ERR trap and set -E

While at it, stop incrementing LINENO inside traps

function                                             old     new   delta
evaltree                                             567     762    +195
evalfun                                              268     348     +80
trapcmd                                              286     333     +47
dotrap                                               129     157     +28
exitshell                                            120     139     +19
readtoken1                                          3096    3110     +14
nlprompt                                              25      39     +14
nlnoprompt                                            19      33     +14
.rodata                                           104245  104255     +10
forkchild                                            610     617      +7
optletters_optnames                                   64      68      +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 11/0 up/down: 432/0)            Total: 432 bytes

Signed-off-by: Roberto A. Foglietta <roberto.foglietta@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 69 insertions, 17 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 53c140930..cfe0433a8 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -348,6 +348,7 @@ static const char *const optletters_optnames[] = {
         "a"   "allexport",
         "b"   "notify",
         "u"   "nounset",
+        "E"   "errtrace",
         "\0"  "vi"
 #if BASH_PIPEFAIL
         ,"\0"  "pipefail"
@@ -442,15 +443,16 @@ struct globals_misc {
 #define aflag optlist[11]
 #define bflag optlist[12]
 #define uflag optlist[13]
-#define viflag optlist[14]
+#define Eflag optlist[14]
+#define viflag optlist[15]
 #if BASH_PIPEFAIL
-# define pipefail optlist[15]
+# define pipefail optlist[16]
 #else
 # define pipefail 0
 #endif
 #if DEBUG
-# define nolog optlist[15 + BASH_PIPEFAIL]
-# define debug optlist[16 + BASH_PIPEFAIL]
+# define nolog optlist[16 + BASH_PIPEFAIL]
+# define debug optlist[17 + BASH_PIPEFAIL]
 #endif
 
         /* trap handler commands */
@@ -468,7 +470,11 @@ struct globals_misc {
         /* indicates specified signal received */
         uint8_t gotsig[NSIG - 1]; /* offset by 1: "signal" 0 is meaningless */
         uint8_t may_have_traps; /* 0: definitely no traps are set, 1: some traps may be set */
-        char *trap[NSIG];
+        char *trap[NSIG + 1];
+/* trap[0] is EXIT trap, trap[NTRAP_ERR] is ERR trap, other trap[i] are signal traps */
+#define NTRAP_ERR  NSIG
+#define NTRAP_LAST NSIG
+
         char **trap_ptr;        /* used only by "trap hack" */
 
         /* Rarely referenced stuff */
@@ -2166,6 +2172,8 @@ struct globals_var {
         struct var varinit[ARRAY_SIZE(varinit_data)];
         int lineno;
         char linenovar[sizeof("LINENO=") + sizeof(int)*3];
+        unsigned trap_depth;
+        bool in_trap_ERR; /* ERR cannot recurse, no need to be a counter */
 };
 extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var;
 #define G_var (*ash_ptr_to_globals_var)
@@ -2176,6 +2184,8 @@ extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var;
 #define varinit       (G_var.varinit      )
 #define lineno        (G_var.lineno       )
 #define linenovar     (G_var.linenovar    )
+#define trap_depth    (G_var.trap_depth   )
+#define in_trap_ERR   (G_var.in_trap_ERR  )
 #define vifs      varinit[0]
 #if ENABLE_ASH_MAIL
 # define vmail    varinit[1]
@@ -5163,13 +5173,13 @@ clear_traps(void)
         char **tp;
 
         INT_OFF;
-        for (tp = trap; tp < &trap[NSIG]; tp++) {
+        for (tp = trap; tp <= &trap[NTRAP_LAST]; tp++) {
                 if (*tp && **tp) {      /* trap not NULL or "" (SIG_IGN) */
                         if (trap_ptr == trap)
                                 free(*tp);
                         /* else: it "belongs" to trap_ptr vector, don't free */
                         *tp = NULL;
-                        if ((tp - trap) != 0)
+                        if ((tp - trap) != 0 && (tp - trap) < NSIG)
                                 setsignal(tp - trap);
                 }
         }
@@ -9253,7 +9263,9 @@ dotrap(void)
                 *g = 0;
                 if (!p)
                         continue;
+                trap_depth++;
                 evalstring(p, 0);
+                trap_depth--;
                 if (evalskip != SKIPFUNC)
                         exitstatus = status;
         }
@@ -9321,7 +9333,7 @@ evaltree(union node *n, int flags)
         case NCMD:
                 evalfn = evalcommand;
  checkexit:
-                if (eflag && !(flags & EV_TESTED))
+                if (!(flags & EV_TESTED))
                         checkexit = ~0;
                 goto calleval;
         case NFOR:
@@ -9395,8 +9407,32 @@ evaltree(union node *n, int flags)
          */
         dotrap();
 
-        if (checkexit & status)
-                raise_exception(EXEND);
+        if (checkexit & status) {
+                if (trap[NTRAP_ERR] && !in_trap_ERR) {
+                        int err;
+                        struct jmploc *volatile savehandler = exception_handler;
+                        struct jmploc jmploc;
+
+                        in_trap_ERR = 1;
+                        trap_depth++;
+                        err = setjmp(jmploc.loc);
+                        if (!err) {
+                                exception_handler = &jmploc;
+                                savestatus = exitstatus;
+                                evalstring(trap[NTRAP_ERR], 0);
+                        }
+                        trap_depth--;
+                        in_trap_ERR = 0;
+
+                        exception_handler = savehandler;
+                        if (err && exception_type != EXERROR)
+                                longjmp(exception_handler->loc, 1);
+
+                        exitstatus = savestatus;
+                }
+                if (eflag)
+                        raise_exception(EXEND);
+        }
         if (flags & EV_EXIT)
                 raise_exception(EXEND);
 
@@ -9861,7 +9897,12 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         struct jmploc jmploc;
         int e;
         int savefuncline;
+        char *savetrap = NULL;
 
+        if (!Eflag) {
+                savetrap = trap[NTRAP_ERR];
+                trap[NTRAP_ERR] = NULL;
+        }
         saveparam = shellparam;
         savefuncline = funcline;
         savehandler = exception_handler;
@@ -9884,6 +9925,12 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         evaltree(func->n.ndefun.body, flags & EV_TESTED);
  funcdone:
         INT_OFF;
+        if (savetrap) {
+                if (!trap[NTRAP_ERR])
+                        trap[NTRAP_ERR] = savetrap;
+                else
+                        free(savetrap);
+        }
         funcline = savefuncline;
         freefunc(func);
         freeparam(&shellparam);
@@ -10912,13 +10959,15 @@ preadbuffer(void)
 static void
 nlprompt(void)
 {
-        g_parsefile->linno++;
+        if (trap_depth == 0)
+                g_parsefile->linno++;
         setprompt_if(doprompt, 2);
 }
 static void
 nlnoprompt(void)
 {
-        g_parsefile->linno++;
+        if (trap_depth == 0)
+                g_parsefile->linno++;
         needprompt = doprompt;
 }
 
@@ -12620,7 +12669,8 @@ checkend: {
 
                 if (c == '\n' || c == PEOF) {
                         c = PEOF;
-                        g_parsefile->linno++;
+                        if (trap_depth == 0)
+                                g_parsefile->linno++;
                         needprompt = doprompt;
                 } else {
                         int len_here;
@@ -13869,7 +13919,7 @@ trapcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
         nextopt(nullstr);
         ap = argptr;
         if (!*ap) {
-                for (signo = 0; signo < NSIG; signo++) {
+                for (signo = 0; signo <= NTRAP_LAST; signo++) {
                         char *tr = trap_ptr[signo];
                         if (tr) {
                                 /* note: bash adds "SIG", but only if invoked
@@ -13878,7 +13928,7 @@ trapcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                                  * We are printing short names: */
                                 out1fmt("trap -- %s %s\n",
                                                 single_quote(tr),
-                                                get_signame(signo));
+                                                (signo == NTRAP_ERR) ? "ERR" : get_signame(signo));
                 /* trap_ptr != trap only if we are in special-cased `trap` code.
                  * In this case, we will exit very soon, no need to free(). */
                                 /* if (trap_ptr != trap && tp[0]) */
@@ -13904,7 +13954,7 @@ trapcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 
         exitcode = 0;
         while (*ap) {
-                signo = get_signum(*ap);
+                signo = strcmp(*ap, "ERR") == 0 ? NTRAP_ERR : get_signum(*ap);
                 if (signo < 0) {
                         /* Mimic bash message exactly */
                         ash_msg("%s: invalid signal specification", *ap);
@@ -13923,7 +13973,7 @@ trapcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                 }
                 free(trap[signo]);
                 trap[signo] = action;
-                if (signo != 0)
+                if (signo != 0 && signo < NSIG)
                         setsignal(signo);
                 INT_ON;
  next:
@@ -14348,7 +14398,9 @@ exitshell(void)
         if (p) {
                 trap[0] = NULL;
                 evalskip = 0;
+                trap_depth++;
                 evalstring(p, 0);
+                trap_depth--;
                 evalskip = SKIPFUNCDEF;
                 /*free(p); - we'll exit soon */
         }