From aecb5206e2321231a9a615c2f8cc4703bd8ab3cc Mon Sep 17 00:00:00 2001
From: "Todd C. Miller" <Todd.Miller@courtesan.com>
Date: Thu, 29 Mar 2012 10:33:40 -0400
Subject: [PATCH] Fix compiler warnings on some platforms and provide a better
 method of defeating gcc's warn_unused_result attribute.

---
 common/sudo_debug.c            |   2 +-
 config.h.in                    |   9 +++
 plugins/sample/sample_plugin.c |   4 +-
 plugins/sudoers/iolog.c        |   4 +-
 plugins/sudoers/toke.c         | 132 +++++++++++++++++----------------
 plugins/sudoers/toke.l         |   2 +
 plugins/sudoers/visudo.c       |  13 ++--
 src/env_hooks.c                |  32 +++++---
 src/exec.c                     |   6 +-
 src/exec_pty.c                 |   9 +--
 src/tgetpass.c                 |   3 +-
 11 files changed, 117 insertions(+), 99 deletions(-)

diff --git a/common/sudo_debug.c b/common/sudo_debug.c
index e105b5d59..84b1ad1ae 100644
--- a/common/sudo_debug.c
+++ b/common/sudo_debug.c
@@ -302,7 +302,7 @@ sudo_debug_write(const char *str, int len)
 	iov[0].iov_len = 16;
 
 	/* Write message in a single syscall */
-	(void) writev(sudo_debug_fd, iov, iovcnt);
+	ignore_result(writev(sudo_debug_fd, iov, iovcnt));
 	break;
     }
 }
diff --git a/config.h.in b/config.h.in
index dca0786c0..0ce4afc5b 100644
--- a/config.h.in
+++ b/config.h.in
@@ -912,6 +912,15 @@
 # endif /* HAVE_ST_MTIMESPEC */
 #endif /* HAVE_ST_MTIM */
 
+#ifdef __GNUC__
+# define ignore_result(x) do {						       \
+    __typeof__(x) y = (x);						       \
+    (void)y;								       \
+} while(0)
+#else
+# define ignore_result(x)	(void)(x)
+#endif
+
 /* GNU stow needs /etc/sudoers to be a symlink. */
 #ifdef USE_STOW
 # define stat_sudoers	stat
diff --git a/plugins/sample/sample_plugin.c b/plugins/sample/sample_plugin.c
index afbf3d8c3..efa498930 100644
--- a/plugins/sample/sample_plugin.c
+++ b/plugins/sample/sample_plugin.c
@@ -468,14 +468,14 @@ io_version(int verbose)
 static int
 io_log_input(const char *buf, unsigned int len)
 {
-    fwrite(buf, len, 1, input);
+    ignore_result(fwrite(buf, len, 1, input));
     return true;
 }
 
 static int
 io_log_output(const char *buf, unsigned int len)
 {
-    fwrite(buf, len, 1, output);
+    ignore_result(fwrite(buf, len, 1, output));
     return true;
 }
 
diff --git a/plugins/sudoers/iolog.c b/plugins/sudoers/iolog.c
index 84aeed049..6a11e645d 100644
--- a/plugins/sudoers/iolog.c
+++ b/plugins/sudoers/iolog.c
@@ -632,10 +632,10 @@ sudoers_io_log(const char *buf, unsigned int len, int idx)
 
 #ifdef HAVE_ZLIB_H
     if (iolog_compress)
-	gzwrite(io_fds[idx].g, (const voidp)buf, len);
+	ignore_result(gzwrite(io_fds[idx].g, (const voidp)buf, len));
     else
 #endif
-	fwrite(buf, 1, len, io_fds[idx].f);
+	ignore_result(fwrite(buf, 1, len, io_fds[idx].f));
     delay.tv_sec = now.tv_sec;
     delay.tv_usec = now.tv_usec;
     timevalsub(&delay, &last_time);
diff --git a/plugins/sudoers/toke.c b/plugins/sudoers/toke.c
index e1c6ac1f9..b740aaf24 100644
--- a/plugins/sudoers/toke.c
+++ b/plugins/sudoers/toke.c
@@ -1506,6 +1506,8 @@ int (*trace_print)(const char *msg) = sudoers_trace_print;
 	return (n);		\
 } while (0)
 
+#define ECHO	ignore_result(fwrite(yytext, yyleng, 1, yyout))
+
 #define	push_include(_p)	(_push_include((_p), false))
 #define	push_includedir(_p)	(_push_include((_p), true))
 #define YY_NO_INPUT 1
@@ -1520,7 +1522,7 @@ int (*trace_print)(const char *msg) = sudoers_trace_print;
 
 #define INSTR 5
 
-#line 1523 "lex.yy.c"
+#line 1525 "lex.yy.c"
 
 /* Macros after this point can all be overridden by user definitions in
  * section 1.
@@ -1674,9 +1676,9 @@ YY_DECL
 	register char *yy_cp, *yy_bp;
 	register int yy_act;
 
-#line 131 "toke.l"
+#line 133 "toke.l"
 
-#line 1679 "lex.yy.c"
+#line 1681 "lex.yy.c"
 
 	if ( yy_init )
 		{
@@ -1762,7 +1764,7 @@ do_action:	/* This label is used only to access EOF actions. */
 
 case 1:
 YY_RULE_SETUP
-#line 132 "toke.l"
+#line 134 "toke.l"
 {
 			    LEXTRACE(", ");
 			    LEXRETURN(',');
@@ -1770,12 +1772,12 @@ YY_RULE_SETUP
 	YY_BREAK
 case 2:
 YY_RULE_SETUP
-#line 137 "toke.l"
+#line 139 "toke.l"
 BEGIN STARTDEFS;
 	YY_BREAK
 case 3:
 YY_RULE_SETUP
-#line 139 "toke.l"
+#line 141 "toke.l"
 {
 			    BEGIN INDEFS;
 			    LEXTRACE("DEFVAR ");
@@ -1787,7 +1789,7 @@ YY_RULE_SETUP
 
 case 4:
 YY_RULE_SETUP
-#line 148 "toke.l"
+#line 150 "toke.l"
 {
 			    BEGIN STARTDEFS;
 			    LEXTRACE(", ");
@@ -1796,7 +1798,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 5:
 YY_RULE_SETUP
-#line 154 "toke.l"
+#line 156 "toke.l"
 {
 			    LEXTRACE("= ");
 			    LEXRETURN('=');
@@ -1804,7 +1806,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 6:
 YY_RULE_SETUP
-#line 159 "toke.l"
+#line 161 "toke.l"
 {
 			    LEXTRACE("+= ");
 			    LEXRETURN('+');
@@ -1812,7 +1814,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 7:
 YY_RULE_SETUP
-#line 164 "toke.l"
+#line 166 "toke.l"
 {
 			    LEXTRACE("-= ");
 			    LEXRETURN('-');
@@ -1820,7 +1822,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 8:
 YY_RULE_SETUP
-#line 169 "toke.l"
+#line 171 "toke.l"
 {
 			    LEXTRACE("BEGINSTR ");
 			    yylval.string = NULL;
@@ -1830,7 +1832,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 9:
 YY_RULE_SETUP
-#line 176 "toke.l"
+#line 178 "toke.l"
 {
 			    LEXTRACE("WORD(2) ");
 			    if (!fill(yytext, yyleng))
@@ -1842,7 +1844,7 @@ YY_RULE_SETUP
 
 case 10:
 YY_RULE_SETUP
-#line 185 "toke.l"
+#line 187 "toke.l"
 {
 			    /* Line continuation char followed by newline. */
 			    sudolineno++;
@@ -1851,7 +1853,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 11:
 YY_RULE_SETUP
-#line 191 "toke.l"
+#line 193 "toke.l"
 {
 			    LEXTRACE("ENDSTR ");
 			    BEGIN prev_state;
@@ -1886,7 +1888,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 12:
 YY_RULE_SETUP
-#line 223 "toke.l"
+#line 225 "toke.l"
 {
 			    LEXTRACE("BACKSLASH ");
 			    if (!append(yytext, yyleng))
@@ -1895,7 +1897,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 13:
 YY_RULE_SETUP
-#line 229 "toke.l"
+#line 231 "toke.l"
 {
 			    LEXTRACE("STRBODY ");
 			    if (!append(yytext, yyleng))
@@ -1906,7 +1908,7 @@ YY_RULE_SETUP
 
 case 14:
 YY_RULE_SETUP
-#line 237 "toke.l"
+#line 239 "toke.l"
 {
 			    /* quoted fnmatch glob char, pass verbatim */
 			    LEXTRACE("QUOTEDCHAR ");
@@ -1917,7 +1919,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 15:
 YY_RULE_SETUP
-#line 245 "toke.l"
+#line 247 "toke.l"
 {
 			    /* quoted sudoers special char, strip backslash */
 			    LEXTRACE("QUOTEDCHAR ");
@@ -1928,7 +1930,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 16:
 YY_RULE_SETUP
-#line 253 "toke.l"
+#line 255 "toke.l"
 {
 			    BEGIN INITIAL;
 			    yyless(0);
@@ -1937,7 +1939,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 17:
 YY_RULE_SETUP
-#line 259 "toke.l"
+#line 261 "toke.l"
 {
 			    LEXTRACE("ARG ");
 			    if (!fill_args(yytext, yyleng, sawspace))
@@ -1948,7 +1950,7 @@ YY_RULE_SETUP
 
 case 18:
 YY_RULE_SETUP
-#line 267 "toke.l"
+#line 269 "toke.l"
 {
 			    char *path;
 
@@ -1969,7 +1971,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 19:
 YY_RULE_SETUP
-#line 285 "toke.l"
+#line 287 "toke.l"
 {
 			    char *path;
 
@@ -1993,7 +1995,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 20:
 YY_RULE_SETUP
-#line 306 "toke.l"
+#line 308 "toke.l"
 {
 			    char deftype;
 			    int n;
@@ -2036,7 +2038,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 21:
 YY_RULE_SETUP
-#line 346 "toke.l"
+#line 348 "toke.l"
 {
 			    int n;
 
@@ -2065,7 +2067,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 22:
 YY_RULE_SETUP
-#line 372 "toke.l"
+#line 374 "toke.l"
 {
 				/* cmnd does not require passwd for this user */
 			    	LEXTRACE("NOPASSWD ");
@@ -2074,7 +2076,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 23:
 YY_RULE_SETUP
-#line 378 "toke.l"
+#line 380 "toke.l"
 {
 				/* cmnd requires passwd for this user */
 			    	LEXTRACE("PASSWD ");
@@ -2083,7 +2085,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 24:
 YY_RULE_SETUP
-#line 384 "toke.l"
+#line 386 "toke.l"
 {
 			    	LEXTRACE("NOEXEC ");
 			    	LEXRETURN(NOEXEC);
@@ -2091,7 +2093,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 25:
 YY_RULE_SETUP
-#line 389 "toke.l"
+#line 391 "toke.l"
 {
 			    	LEXTRACE("EXEC ");
 			    	LEXRETURN(EXEC);
@@ -2099,7 +2101,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 26:
 YY_RULE_SETUP
-#line 394 "toke.l"
+#line 396 "toke.l"
 {
 			    	LEXTRACE("SETENV ");
 			    	LEXRETURN(SETENV);
@@ -2107,7 +2109,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 27:
 YY_RULE_SETUP
-#line 399 "toke.l"
+#line 401 "toke.l"
 {
 			    	LEXTRACE("NOSETENV ");
 			    	LEXRETURN(NOSETENV);
@@ -2115,7 +2117,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 28:
 YY_RULE_SETUP
-#line 404 "toke.l"
+#line 406 "toke.l"
 {
 			    	LEXTRACE("LOG_OUTPUT ");
 			    	LEXRETURN(LOG_OUTPUT);
@@ -2123,7 +2125,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 29:
 YY_RULE_SETUP
-#line 409 "toke.l"
+#line 411 "toke.l"
 {
 			    	LEXTRACE("NOLOG_OUTPUT ");
 			    	LEXRETURN(NOLOG_OUTPUT);
@@ -2131,7 +2133,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 30:
 YY_RULE_SETUP
-#line 414 "toke.l"
+#line 416 "toke.l"
 {
 			    	LEXTRACE("LOG_INPUT ");
 			    	LEXRETURN(LOG_INPUT);
@@ -2139,7 +2141,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 31:
 YY_RULE_SETUP
-#line 419 "toke.l"
+#line 421 "toke.l"
 {
 			    	LEXTRACE("NOLOG_INPUT ");
 			    	LEXRETURN(NOLOG_INPUT);
@@ -2147,7 +2149,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 32:
 YY_RULE_SETUP
-#line 424 "toke.l"
+#line 426 "toke.l"
 {
 			    /* empty group or netgroup */
 			    LEXTRACE("ERROR ");
@@ -2156,7 +2158,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 33:
 YY_RULE_SETUP
-#line 430 "toke.l"
+#line 432 "toke.l"
 {
 			    /* netgroup */
 			    if (!fill(yytext, yyleng))
@@ -2167,7 +2169,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 34:
 YY_RULE_SETUP
-#line 438 "toke.l"
+#line 440 "toke.l"
 {
 			    /* group */
 			    if (!fill(yytext, yyleng))
@@ -2178,7 +2180,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 35:
 YY_RULE_SETUP
-#line 446 "toke.l"
+#line 448 "toke.l"
 {
 			    if (!fill(yytext, yyleng))
 				yyterminate();
@@ -2188,7 +2190,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 36:
 YY_RULE_SETUP
-#line 453 "toke.l"
+#line 455 "toke.l"
 {
 			    if (!fill(yytext, yyleng))
 				yyterminate();
@@ -2198,7 +2200,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 37:
 YY_RULE_SETUP
-#line 460 "toke.l"
+#line 462 "toke.l"
 {
 			    if (!ipv6_valid(yytext)) {
 				LEXTRACE("ERROR ");
@@ -2212,7 +2214,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 38:
 YY_RULE_SETUP
-#line 471 "toke.l"
+#line 473 "toke.l"
 {
 			    if (!ipv6_valid(yytext)) {
 				LEXTRACE("ERROR ");
@@ -2226,7 +2228,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 39:
 YY_RULE_SETUP
-#line 482 "toke.l"
+#line 484 "toke.l"
 {
 			    LEXTRACE("ALL ");
 			    LEXRETURN(ALL);
@@ -2235,7 +2237,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 40:
 YY_RULE_SETUP
-#line 488 "toke.l"
+#line 490 "toke.l"
 {
 #ifdef HAVE_SELINUX
 			    LEXTRACE("ROLE ");
@@ -2247,7 +2249,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 41:
 YY_RULE_SETUP
-#line 497 "toke.l"
+#line 499 "toke.l"
 {
 #ifdef HAVE_SELINUX
 			    LEXTRACE("TYPE ");
@@ -2259,7 +2261,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 42:
 YY_RULE_SETUP
-#line 506 "toke.l"
+#line 508 "toke.l"
 {
 #ifndef HAVE_SELINUX
 			got_alias:
@@ -2272,7 +2274,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 43:
 YY_RULE_SETUP
-#line 516 "toke.l"
+#line 518 "toke.l"
 {
 			    /* no command args allowed for Defaults!/path */
 			    if (!fill_cmnd(yytext, yyleng))
@@ -2283,7 +2285,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 44:
 YY_RULE_SETUP
-#line 524 "toke.l"
+#line 526 "toke.l"
 {
 			    BEGIN GOTCMND;
 			    LEXTRACE("COMMAND ");
@@ -2293,7 +2295,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 45:
 YY_RULE_SETUP
-#line 531 "toke.l"
+#line 533 "toke.l"
 {
 			    /* directories can't have args... */
 			    if (yytext[yyleng - 1] == '/') {
@@ -2311,7 +2313,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 46:
 YY_RULE_SETUP
-#line 546 "toke.l"
+#line 548 "toke.l"
 {
 			    LEXTRACE("BEGINSTR ");
 			    yylval.string = NULL;
@@ -2321,7 +2323,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 47:
 YY_RULE_SETUP
-#line 553 "toke.l"
+#line 555 "toke.l"
 {
 			    /* a word */
 			    if (!fill(yytext, yyleng))
@@ -2332,7 +2334,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 48:
 YY_RULE_SETUP
-#line 561 "toke.l"
+#line 563 "toke.l"
 {
 			    LEXTRACE("( ");
 			    LEXRETURN('(');
@@ -2340,7 +2342,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 49:
 YY_RULE_SETUP
-#line 566 "toke.l"
+#line 568 "toke.l"
 {
 			    LEXTRACE(") ");
 			    LEXRETURN(')');
@@ -2348,7 +2350,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 50:
 YY_RULE_SETUP
-#line 571 "toke.l"
+#line 573 "toke.l"
 {
 			    LEXTRACE(", ");
 			    LEXRETURN(',');
@@ -2356,7 +2358,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 51:
 YY_RULE_SETUP
-#line 576 "toke.l"
+#line 578 "toke.l"
 {
 			    LEXTRACE("= ");
 			    LEXRETURN('=');
@@ -2364,7 +2366,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 52:
 YY_RULE_SETUP
-#line 581 "toke.l"
+#line 583 "toke.l"
 {
 			    LEXTRACE(": ");
 			    LEXRETURN(':');
@@ -2372,7 +2374,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 53:
 YY_RULE_SETUP
-#line 586 "toke.l"
+#line 588 "toke.l"
 {
 			    if (yyleng & 1) {
 				LEXTRACE("!");
@@ -2382,7 +2384,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 54:
 YY_RULE_SETUP
-#line 593 "toke.l"
+#line 595 "toke.l"
 {
 			    if (YY_START == INSTR) {
 				LEXTRACE("ERROR ");
@@ -2397,14 +2399,14 @@ YY_RULE_SETUP
 	YY_BREAK
 case 55:
 YY_RULE_SETUP
-#line 605 "toke.l"
+#line 607 "toke.l"
 {			/* throw away space/tabs */
 			    sawspace = true;	/* but remember for fill_args */
 			}
 	YY_BREAK
 case 56:
 YY_RULE_SETUP
-#line 609 "toke.l"
+#line 611 "toke.l"
 {
 			    sawspace = true;	/* remember for fill_args */
 			    sudolineno++;
@@ -2413,7 +2415,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 57:
 YY_RULE_SETUP
-#line 615 "toke.l"
+#line 617 "toke.l"
 {
 			    BEGIN INITIAL;
 			    sudolineno++;
@@ -2424,7 +2426,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 58:
 YY_RULE_SETUP
-#line 623 "toke.l"
+#line 625 "toke.l"
 {
 			    LEXTRACE("ERROR ");
 			    LEXRETURN(ERROR);
@@ -2436,7 +2438,7 @@ case YY_STATE_EOF(GOTCMND):
 case YY_STATE_EOF(STARTDEFS):
 case YY_STATE_EOF(INDEFS):
 case YY_STATE_EOF(INSTR):
-#line 628 "toke.l"
+#line 630 "toke.l"
 {
 			    if (YY_START != INITIAL) {
 			    	BEGIN INITIAL;
@@ -2449,10 +2451,10 @@ case YY_STATE_EOF(INSTR):
 	YY_BREAK
 case 59:
 YY_RULE_SETUP
-#line 638 "toke.l"
+#line 640 "toke.l"
 ECHO;
 	YY_BREAK
-#line 2455 "lex.yy.c"
+#line 2457 "lex.yy.c"
 
 	case YY_END_OF_BUFFER:
 		{
@@ -3343,7 +3345,7 @@ int main()
 	return 0;
 	}
 #endif
-#line 638 "toke.l"
+#line 640 "toke.l"
 
 struct path_list {
     char *path;
diff --git a/plugins/sudoers/toke.l b/plugins/sudoers/toke.l
index e830f84dd..912d4d6bc 100644
--- a/plugins/sudoers/toke.l
+++ b/plugins/sudoers/toke.l
@@ -102,6 +102,8 @@ int (*trace_print)(const char *msg) = sudoers_trace_print;
 	return (n);		\
 } while (0)
 
+#define ECHO	ignore_result(fwrite(yytext, yyleng, 1, yyout))
+
 #define	push_include(_p)	(_push_include((_p), false))
 #define	push_includedir(_p)	(_push_include((_p), true))
 %}
diff --git a/plugins/sudoers/visudo.c b/plugins/sudoers/visudo.c
index 923e1235f..7e5312580 100644
--- a/plugins/sudoers/visudo.c
+++ b/plugins/sudoers/visudo.c
@@ -563,9 +563,9 @@ install_sudoers(struct sudoersfile *sp, bool oldperms)
 	(void) unlink(sp->tpath);
 	if (!oldperms && fstat(sp->fd, &sb) != -1) {
 	    if (sb.st_uid != SUDOERS_UID || sb.st_gid != SUDOERS_GID)
-		(void) chown(sp->path, SUDOERS_UID, SUDOERS_GID);
+		ignore_result(chown(sp->path, SUDOERS_UID, SUDOERS_GID));
 	    if ((sb.st_mode & 0777) != SUDOERS_MODE)
-		(void) chmod(sp->path, SUDOERS_MODE);
+		ignore_result(chmod(sp->path, SUDOERS_MODE));
 	}
 	rval = true;
 	goto done;
@@ -1279,11 +1279,10 @@ quit(int signo)
 #define	emsg	 " exiting due to signal: "
     myname = getprogname();
     signame = strsignal(signo);
-    if (write(STDERR_FILENO, myname, strlen(myname)) == -1 ||
-	write(STDERR_FILENO, emsg, sizeof(emsg) - 1) == -1 ||
-	write(STDERR_FILENO, signame, strlen(signame)) == -1 ||
-	write(STDERR_FILENO, "\n", 1) == -1)
-	/* shut up glibc */;
+    ignore_result(write(STDERR_FILENO, myname, strlen(myname)));
+    ignore_result(write(STDERR_FILENO, emsg, sizeof(emsg) - 1));
+    ignore_result(write(STDERR_FILENO, signame, strlen(signame)));
+    ignore_result(write(STDERR_FILENO, "\n", 1));
     _exit(signo);
 }
 
diff --git a/src/env_hooks.c b/src/env_hooks.c
index 5b60471c5..c518cb1bc 100644
--- a/src/env_hooks.c
+++ b/src/env_hooks.c
@@ -67,6 +67,8 @@ rpl_getenv(const char *name)
     return val;
 }
 
+typedef char * (*sudo_fn_getenv_t)(const char *);
+
 char *
 getenv(const char *name)
 {
@@ -79,9 +81,9 @@ getenv(const char *name)
 	    return NULL;
 	default: {
 #if defined(HAVE_DLOPEN) && defined(RTLD_NEXT)
-	    char * (*fn)(const char *);
+	    sudo_fn_getenv_t fn;
 
-	    fn = dlsym(RTLD_NEXT, "getenv");
+	    fn = (sudo_fn_getenv_t)dlsym(RTLD_NEXT, "getenv");
 	    if (fn != NULL)
 		return fn(name);
 #endif /* HAVE_DLOPEN && RTLD_NEXT */
@@ -132,6 +134,8 @@ rpl_putenv(PUTENV_CONST char *string)
     return 0;
 }
 
+typedef int (*sudo_fn_putenv_t)(PUTENV_CONST char *);
+
 int
 putenv(PUTENV_CONST char *string)
 {
@@ -142,9 +146,9 @@ putenv(PUTENV_CONST char *string)
 	    return -1;
 	default: {
 #if defined(HAVE_DLOPEN) && defined(RTLD_NEXT)
-	    int (*fn)(PUTENV_CONST char *);
+	    sudo_fn_putenv_t fn;
 
-	    fn = dlsym(RTLD_NEXT, "putenv");
+	    fn = (sudo_fn_putenv_t)dlsym(RTLD_NEXT, "putenv");
 	    if (fn != NULL)
 		return fn(string);
 #endif /* HAVE_DLOPEN && RTLD_NEXT */
@@ -195,6 +199,8 @@ rpl_setenv(const char *var, const char *val, int overwrite)
     return rpl_putenv(envstr);
 }
 
+typedef int (*sudo_fn_setenv_t)(const char *, const char *, int);
+
 int
 setenv(const char *var, const char *val, int overwrite)
 {
@@ -205,9 +211,9 @@ setenv(const char *var, const char *val, int overwrite)
 	    return -1;
 	default: {
 #if defined(HAVE_SETENV) && defined(HAVE_DLOPEN) && defined(RTLD_NEXT)
-	    int (*fn)(const char *, const char *, int);
+	    sudo_fn_setenv_t fn;
 
-	    fn = dlsym(RTLD_NEXT, "setenv");
+	    fn = (sudo_fn_setenv_t)dlsym(RTLD_NEXT, "setenv");
 	    if (fn != NULL)
 		return fn(var, val, overwrite);
 #endif /* HAVE_SETENV && HAVE_DLOPEN && RTLD_NEXT */
@@ -252,6 +258,12 @@ rpl_unsetenv(const char *var)
 #endif
 }
 
+#ifdef UNSETENV_VOID
+typedef void (*sudo_fn_unsetenv_t)(const char *);
+#else
+typedef int (*sudo_fn_unsetenv_t)(const char *);
+#endif
+
 #ifdef UNSETENV_VOID
 void
 unsetenv(const char *var)
@@ -263,9 +275,9 @@ unsetenv(const char *var)
 	    return -1;
 	default: {
 #if defined(HAVE_UNSETENV) && defined(HAVE_DLOPEN) && defined(RTLD_NEXT)
-	    void (*fn)(const char *);
+	    sudo_fn_unsetenv_t fn;
 
-	    fn = dlsym(RTLD_NEXT, "unsetenv");
+	    fn = (sudo_fn_unsetenv_t)dlsym(RTLD_NEXT, "unsetenv");
 	    if (fn != NULL)
 		fn(var);
 	    else
@@ -285,9 +297,9 @@ unsetenv(const char *var)
 	    return -1;
 	default: {
 #if defined(HAVE_UNSETENV) && defined(HAVE_DLOPEN) && defined(RTLD_NEXT)
-	    int (*fn)(const char *);
+	    sudo_fn_unsetenv_t fn;
 
-	    fn = dlsym(RTLD_NEXT, "unsetenv");
+	    fn = (sudo_fn_unsetenv_t)dlsym(RTLD_NEXT, "unsetenv");
 	    if (fn != NULL)
 		return fn(var);
 #endif /* HAVE_UNSETENV && HAVE_DLOPEN && RTLD_NEXT */
diff --git a/src/exec.c b/src/exec.c
index b48500649..5af8f0203 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -604,8 +604,7 @@ handler(int s)
      * The pipe is non-blocking, if we overflow the kernel's pipe
      * buffer we drop the signal.  This is not a problem in practice.
      */
-    if (write(signal_pipe[1], &signo, sizeof(signo)) == -1)
-	/* shut up glibc */;
+    ignore_result(write(signal_pipe[1], &signo, sizeof(signo)));
 }
 
 #ifdef SA_SIGINFO
@@ -626,8 +625,7 @@ handler_nofwd(int s, siginfo_t *info, void *context)
 	 * The pipe is non-blocking, if we overflow the kernel's pipe
 	 * buffer we drop the signal.  This is not a problem in practice.
 	 */
-	if (write(signal_pipe[1], &signo, sizeof(signo)) == -1)
-	    /* shut up glibc */;
+	ignore_result(write(signal_pipe[1], &signo, sizeof(signo)));
     }
 }
 #endif /* SA_SIGINFO */
diff --git a/src/exec_pty.c b/src/exec_pty.c
index c78e793e5..f4a4804e6 100644
--- a/src/exec_pty.c
+++ b/src/exec_pty.c
@@ -695,11 +695,9 @@ pty_close(struct command_status *cstat)
 		io_fds[SFD_USERTTY] : STDOUT_FILENO;
 	    if (write(n, reason, strlen(reason)) != -1) {
 		if (WCOREDUMP(cstat->val)) {
-		    if (write(n, " (core dumped)", 14) == -1)
-			/* shut up glibc */;
+		    ignore_result(write(n, " (core dumped)", 14));
 		}
-		if (write(n, "\n", 1) == -1)
-		    /* shut up glibc */;
+		ignore_result(write(n, "\n", 1));
 	    }
 	}
     }
@@ -961,8 +959,7 @@ exec_monitor(struct command_details *details, int backchannel)
 	exec_pty(details, &errpipe[1]);
 	cstat.type = CMD_ERRNO;
 	cstat.val = errno;
-	if (write(errpipe[1], &cstat, sizeof(cstat)) == -1)
-	    /* shut up glibc */;
+	ignore_result(write(errpipe[1], &cstat, sizeof(cstat)));
 	_exit(1);
     }
     close(errpipe[1]);
diff --git a/src/tgetpass.c b/src/tgetpass.c
index 8b12bdc8e..e9915b2bd 100644
--- a/src/tgetpass.c
+++ b/src/tgetpass.c
@@ -298,8 +298,7 @@ getln(int fd, char *buf, size_t bufsiz, int feedback)
 		}
 		continue;
 	    }
-	    if (write(fd, "*", 1) == -1)
-		/* shut up glibc */;
+	    ignore_result(write(fd, "*", 1));
 	}
 	*cp++ = c;
     }
-- 
2.40.0