awk: fix segfault on closing non-opened file

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 102 insertions, 86 deletions

diff --git a/editors/awk.c b/editors/awk.c
index 2245cad03..fb3bf6b47 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -283,88 +283,80 @@ enum {
 #define OC_B    OC_BUILTIN
 
 static const char tokenlist[] ALIGN1 =
-        "\1("       NTC
-        "\1)"       NTC
-        "\1/"       NTC                                 /* REGEXP */
-        "\2>>"      "\1>"       "\1|"       NTC         /* OUTRDR */
-        "\2++"      "\2--"      NTC                     /* UOPPOST */
-        "\2++"      "\2--"      "\1$"       NTC         /* UOPPRE1 */
-        "\2=="      "\1="       "\2+="      "\2-="      /* BINOPX */
-        "\2*="      "\2/="      "\2%="      "\2^="
-        "\1+"       "\1-"       "\3**="     "\2**"
-        "\1/"       "\1%"       "\1^"       "\1*"
-        "\2!="      "\2>="      "\2<="      "\1>"
-        "\1<"       "\2!~"      "\1~"       "\2&&"
-        "\2||"      "\1?"       "\1:"       NTC
-        "\2in"      NTC
-        "\1,"       NTC
-        "\1|"       NTC
-        "\1+"       "\1-"       "\1!"       NTC         /* UOPPRE2 */
-        "\1]"       NTC
-        "\1{"       NTC
-        "\1}"       NTC
-        "\1;"       NTC
-        "\1\n"      NTC
-        "\2if"      "\2do"      "\3for"     "\5break"   /* STATX */
-        "\10continue"           "\6delete"  "\5print"
-        "\6printf"  "\4next"    "\10nextfile"
-        "\6return"  "\4exit"    NTC
-        "\5while"   NTC
-        "\4else"    NTC
-
-        "\3and"     "\5compl"   "\6lshift"  "\2or"
-        "\6rshift"  "\3xor"
-        "\5close"   "\6system"  "\6fflush"  "\5atan2"   /* BUILTIN */
-        "\3cos"     "\3exp"     "\3int"     "\3log"
-        "\4rand"    "\3sin"     "\4sqrt"    "\5srand"
-        "\6gensub"  "\4gsub"    "\5index"   "\6length"
-        "\5match"   "\5split"   "\7sprintf" "\3sub"
-        "\6substr"  "\7systime" "\10strftime" "\6mktime"
-        "\7tolower" "\7toupper" NTC
-        "\7getline" NTC
-        "\4func"    "\10function"   NTC
-        "\5BEGIN"   NTC
-        "\3END"     "\0"
+        "\1("         NTC
+        "\1)"         NTC
+        "\1/"         NTC                                   /* REGEXP */
+        "\2>>"        "\1>"         "\1|"       NTC         /* OUTRDR */
+        "\2++"        "\2--"        NTC                     /* UOPPOST */
+        "\2++"        "\2--"        "\1$"       NTC         /* UOPPRE1 */
+        "\2=="        "\1="         "\2+="      "\2-="      /* BINOPX */
+        "\2*="        "\2/="        "\2%="      "\2^="
+        "\1+"         "\1-"         "\3**="     "\2**"
+        "\1/"         "\1%"         "\1^"       "\1*"
+        "\2!="        "\2>="        "\2<="      "\1>"
+        "\1<"         "\2!~"        "\1~"       "\2&&"
+        "\2||"        "\1?"         "\1:"       NTC
+        "\2in"        NTC
+        "\1,"         NTC
+        "\1|"         NTC
+        "\1+"         "\1-"         "\1!"       NTC         /* UOPPRE2 */
+        "\1]"         NTC
+        "\1{"         NTC
+        "\1}"         NTC
+        "\1;"         NTC
+        "\1\n"        NTC
+        "\2if"        "\2do"        "\3for"     "\5break"   /* STATX */
+        "\10continue" "\6delete"    "\5print"
+        "\6printf"    "\4next"      "\10nextfile"
+        "\6return"    "\4exit"      NTC
+        "\5while"     NTC
+        "\4else"      NTC
+
+        "\3and"       "\5compl"     "\6lshift"  "\2or"
+        "\6rshift"    "\3xor"
+        "\5close"     "\6system"    "\6fflush"  "\5atan2"   /* BUILTIN */
+        "\3cos"       "\3exp"       "\3int"     "\3log"
+        "\4rand"      "\3sin"       "\4sqrt"    "\5srand"
+        "\6gensub"    "\4gsub"      "\5index"   "\6length"
+        "\5match"     "\5split"     "\7sprintf" "\3sub"
+        "\6substr"    "\7systime"   "\10strftime" "\6mktime"
+        "\7tolower"   "\7toupper"   NTC
+        "\7getline"   NTC
+        "\4func"      "\10function" NTC
+        "\5BEGIN"     NTC
+        "\3END"
+        /* compiler adds trailing "\0" */
         ;
 
 static const uint32_t tokeninfo[] = {
         0,
         0,
         OC_REGEXP,
-        xS|'a',     xS|'w',     xS|'|',
-        OC_UNARY|xV|P(9)|'p',       OC_UNARY|xV|P(9)|'m',
-        OC_UNARY|xV|P(9)|'P',       OC_UNARY|xV|P(9)|'M',
-            OC_FIELD|xV|P(5),
-        OC_COMPARE|VV|P(39)|5,      OC_MOVE|VV|P(74),
-            OC_REPLACE|NV|P(74)|'+',    OC_REPLACE|NV|P(74)|'-',
-        OC_REPLACE|NV|P(74)|'*',    OC_REPLACE|NV|P(74)|'/',
-            OC_REPLACE|NV|P(74)|'%',    OC_REPLACE|NV|P(74)|'&',
-        OC_BINARY|NV|P(29)|'+',     OC_BINARY|NV|P(29)|'-',
-            OC_REPLACE|NV|P(74)|'&',    OC_BINARY|NV|P(15)|'&',
-        OC_BINARY|NV|P(25)|'/',     OC_BINARY|NV|P(25)|'%',
-            OC_BINARY|NV|P(15)|'&',     OC_BINARY|NV|P(25)|'*',
-        OC_COMPARE|VV|P(39)|4,      OC_COMPARE|VV|P(39)|3,
-            OC_COMPARE|VV|P(39)|0,      OC_COMPARE|VV|P(39)|1,
-        OC_COMPARE|VV|P(39)|2,      OC_MATCH|Sx|P(45)|'!',
-            OC_MATCH|Sx|P(45)|'~',      OC_LAND|Vx|P(55),
-        OC_LOR|Vx|P(59),            OC_TERNARY|Vx|P(64)|'?',
-            OC_COLON|xx|P(67)|':',
-        OC_IN|SV|P(49),
+        xS|'a',                  xS|'w',                  xS|'|',
+        OC_UNARY|xV|P(9)|'p',    OC_UNARY|xV|P(9)|'m',
+        OC_UNARY|xV|P(9)|'P',    OC_UNARY|xV|P(9)|'M',    OC_FIELD|xV|P(5),
+        OC_COMPARE|VV|P(39)|5,   OC_MOVE|VV|P(74),        OC_REPLACE|NV|P(74)|'+', OC_REPLACE|NV|P(74)|'-',
+        OC_REPLACE|NV|P(74)|'*', OC_REPLACE|NV|P(74)|'/', OC_REPLACE|NV|P(74)|'%', OC_REPLACE|NV|P(74)|'&',
+        OC_BINARY|NV|P(29)|'+',  OC_BINARY|NV|P(29)|'-',  OC_REPLACE|NV|P(74)|'&', OC_BINARY|NV|P(15)|'&',
+        OC_BINARY|NV|P(25)|'/',  OC_BINARY|NV|P(25)|'%',  OC_BINARY|NV|P(15)|'&',  OC_BINARY|NV|P(25)|'*',
+        OC_COMPARE|VV|P(39)|4,   OC_COMPARE|VV|P(39)|3,   OC_COMPARE|VV|P(39)|0,   OC_COMPARE|VV|P(39)|1,
+        OC_COMPARE|VV|P(39)|2,   OC_MATCH|Sx|P(45)|'!',   OC_MATCH|Sx|P(45)|'~',   OC_LAND|Vx|P(55),
+        OC_LOR|Vx|P(59),         OC_TERNARY|Vx|P(64)|'?', OC_COLON|xx|P(67)|':',
+        OC_IN|SV|P(49), /* in */
         OC_COMMA|SS|P(80),
         OC_PGETLINE|SV|P(37),
-        OC_UNARY|xV|P(19)|'+',      OC_UNARY|xV|P(19)|'-',
-            OC_UNARY|xV|P(19)|'!',
+        OC_UNARY|xV|P(19)|'+',   OC_UNARY|xV|P(19)|'-',   OC_UNARY|xV|P(19)|'!',
+        0, /* ] */
         0,
         0,
         0,
-        0,
-        0,
-        ST_IF,          ST_DO,          ST_FOR,         OC_BREAK,
-        OC_CONTINUE,                    OC_DELETE|Vx,   OC_PRINT,
-        OC_PRINTF,      OC_NEXT,        OC_NEXTFILE,
-        OC_RETURN|Vx,   OC_EXIT|Nx,
+        0, /* \n */
+        ST_IF,        ST_DO,        ST_FOR,      OC_BREAK,
+        OC_CONTINUE,  OC_DELETE|Vx, OC_PRINT,
+        OC_PRINTF,    OC_NEXT,      OC_NEXTFILE,
+        OC_RETURN|Vx, OC_EXIT|Nx,
         ST_WHILE,
-        0,
+        0, /* else */
 
         OC_B|B_an|P(0x83), OC_B|B_co|P(0x41), OC_B|B_ls|P(0x83), OC_B|B_or|P(0x83),
         OC_B|B_rs|P(0x83), OC_B|B_xo|P(0x83),
@@ -376,9 +368,9 @@ static const uint32_t tokeninfo[] = {
         OC_B|B_ss|P(0x8f), OC_FBLTIN|F_ti,    OC_B|B_ti|P(0x0b), OC_B|B_mt|P(0x0b),
         OC_B|B_lo|P(0x49), OC_B|B_up|P(0x49),
         OC_GETLINE|SV|P(0),
-        0,      0,
+        0,                 0,
         0,
-        0
+        0 /* END */
 };
 
 /* internal variable names and their initial values       */
@@ -1836,6 +1828,8 @@ static int awk_getline(rstream *rsm, var *v)
         int fd, so, eo, r, rp;
         char c, *m, *s;
 
+        debug_printf_eval("entered %s()\n", __func__);
+
         /* we're using our own buffer since we need access to accumulating
          * characters
          */
@@ -1922,6 +1916,8 @@ static int awk_getline(rstream *rsm, var *v)
         rsm->pos = p - eo;
         rsm->size = size;
 
+        debug_printf_eval("returning from %s(): %d\n", __func__, r);
+
         return r;
 }
 
@@ -2347,6 +2343,8 @@ static var *evaluate(node *op, var *res)
         if (!op)
                 return setvar_s(res, NULL);
 
+        debug_printf_eval("entered %s()\n", __func__);
+
         v1 = nvalloc(2);
 
         while (op) {
@@ -2367,7 +2365,7 @@ static var *evaluate(node *op, var *res)
                 opn = (opinfo & OPNMASK);
                 g_lineno = op->lineno;
                 op1 = op->l.n;
-                debug_printf_eval("opinfo:%08x opn:%08x XC:%x\n", opinfo, opn, XC(opinfo & OPCLSMASK));
+                debug_printf_eval("opinfo:%08x opn:%08x\n", opinfo, opn);
 
                 /* execute inevitable things */
                 if (opinfo & OF_RES1)
@@ -2387,6 +2385,7 @@ static var *evaluate(node *op, var *res)
                         debug_printf_eval("L_d:%f\n", L_d);
                 }
 
+                debug_printf_eval("switch(0x%x)\n", XC(opinfo & OPCLSMASK));
                 switch (XC(opinfo & OPCLSMASK)) {
 
                 /* -- iterative node type -- */
@@ -2642,8 +2641,6 @@ static var *evaluate(node *op, var *res)
 
                 /* simple builtins */
                 case XC( OC_FBLTIN ): {
-                        int i;
-                        rstream *rsm;
                         double R_d = R_d; /* for compiler */
 
                         switch (opn) {
@@ -2709,26 +2706,37 @@ static var *evaluate(node *op, var *res)
                                 if (!op1) {
                                         fflush(stdout);
                                 } else if (L.s && *L.s) {
-                                        rsm = newfile(L.s);
+                                        rstream *rsm = newfile(L.s);
                                         fflush(rsm->F);
                                 } else {
                                         fflush_all();
                                 }
                                 break;
 
-                        case F_cl:
-                                i = 0;
+                        case F_cl: {
+                                rstream *rsm;
+                                int err = 0;
                                 rsm = (rstream *)hash_search(fdhash, L.s);
+                                debug_printf_eval("OC_FBLTIN F_cl rsm:%p\n", rsm);
                                 if (rsm) {
-                                        i = rsm->is_pipe ? pclose(rsm->F) : fclose(rsm->F);
+                                        debug_printf_eval("OC_FBLTIN F_cl "
+                                                "rsm->is_pipe:%d, ->F:%p\n",
+                                                rsm->is_pipe, rsm->F);
+                                        /* Can be NULL if open failed. Example:
+                                         * getline line <"doesnt_exist";
+                                         * close("doesnt_exist"); <--- here rsm->F is NULL
+                                         */
+                                        if (rsm->F)
+                                                err = rsm->is_pipe ? pclose(rsm->F) : fclose(rsm->F);
                                         free(rsm->buffer);
                                         hash_remove(fdhash, L.s);
                                 }
-                                if (i != 0)
+                                if (err)
                                         setvar_i(intvar[ERRNO], errno);
-                                R_d = (double)i;
+                                R_d = (double)err;
                                 break;
                         }
+                        } /* switch */
                         setvar_i(res, R_d);
                         break;
                 }
@@ -2877,6 +2885,7 @@ static var *evaluate(node *op, var *res)
         } /* while (op) */
 
         nvfree(v1);
+        debug_printf_eval("returning from %s(): %p\n", __func__, res);
         return res;
 #undef fnargs
 #undef seed
@@ -2919,18 +2928,19 @@ static int is_assignment(const char *expr)
 {
         char *exprc, *s, *s0, *s1;
 
-        exprc = xstrdup(expr);
-        if (!isalnum_(*exprc) || (s = strchr(exprc, '=')) == NULL) {
-                free(exprc);
+        if (!isalnum_(*expr) || (s0 = strchr(expr, '=')) == NULL) {
                 return FALSE;
         }
 
+        exprc = xstrdup(expr);
+        s0 = exprc + (s0 - expr);
         *s++ = '\0';
-        s0 = s1 = s;
+
+        s = s1 = s0;
         while (*s)
                 *s1++ = nextchar(&s);
-
         *s1 = '\0';
+
         setvar_u(newvar(exprc), s0);
         free(exprc);
         return TRUE;
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 56b11ca46..0afe9b9e7 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -77,6 +77,12 @@ testing "awk string cast (bug 725)" \
 testing "awk handles whitespace before array subscript" \
         "awk 'BEGIN { arr [3] = 1; print arr [3] }'" "1\n" "" ""
 
+# GNU awk 3.1.5's "print ERRNO" prints "No such file or directory" instead of "2",
+# do we need to emulate that as well?
+testing "awk handles non-existing file correctly" \
+        "awk 'BEGIN { getline line <\"doesnt_exist\"; print ERRNO; ERRNO=0; close(\"doesnt_exist\"); print ERRNO; print \"Ok\" }'" \
+        "2\n0\nOk\n" "" ""
+
 prg='
 BEGIN {
   u["a"]=1