various: appease the ubuntu gcc monster

Silence warnings about not checking
return values from read and write system calls.

R=r, r2
CC=golang-dev
https://golang.org/cl/2258045

src/cmd/5l/asm.c

@@ -482,7 +482,7 @@ asmb(void)
 	if(dlm){
 		char buf[8];
 
-		write(cout, buf, INITDAT-textsize);
+		ewrite(cout, buf, INITDAT-textsize);
 		textsize = INITDAT;
 	}
 	for(t = 0; t < datsize; t += sizeof(buf)-100) {
@@ -987,7 +987,7 @@ cflush(void)
 	/* no bug if cbc < 0 since obuf(cbuf) followed by ibuf in buf! */
 	n = sizeof(buf.cbuf) - cbc;
 	if(n)
-		write(cout, buf.cbuf, n);
+		ewrite(cout, buf.cbuf, n);
 	cbp = buf.cbuf;
 	cbc = sizeof(buf.cbuf);
 }
@@ -1398,7 +1398,7 @@ datblk(int32 s, int32 n, int str)
 			break;
 		}
 	}
-	write(cout, buf.dbuf, n);
+	ewrite(cout, buf.dbuf, n);
 }
 
 void

src/cmd/6l/asm.c

@@ -575,7 +575,7 @@ asmb(void)
 	if(dlm){
 		char buf[8];
 
-		write(cout, buf, INITDAT-textsize);
+		ewrite(cout, buf, INITDAT-textsize);
 		textsize = INITDAT;
 	}
 
@@ -649,7 +649,7 @@ asmb(void)
 			cflush();
 			elfstro = seek(cout, 0, 1);
 			elfsymsize = elfstro - elfsymo;
-			write(cout, elfstrdat, elfstrsize);
+			ewrite(cout, elfstrdat, elfstrsize);
 
 			if(debug['v'])
 			       Bprint(&bso, "%5.2f dwarf\n", cputime());
@@ -938,7 +938,7 @@ cflush(void)
 
 	n = sizeof(buf.cbuf) - cbc;
 	if(n)
-		write(cout, buf.cbuf, n);
+		ewrite(cout, buf.cbuf, n);
 	cbp = buf.cbuf;
 	cbc = sizeof(buf.cbuf);
 }
@@ -1208,7 +1208,7 @@ datblk(int32 s, int32 n)
 		}
 	}
 
-	write(cout, buf.dbuf, n);
+	ewrite(cout, buf.dbuf, n);
 	if(!debug['a'])
 		return;
 

src/cmd/8l/asm.c

@@ -604,7 +604,7 @@ asmb(void)
 	if(dlm){
 		char buf[8];
 
-		write(cout, buf, INITDAT-textsize);
+		ewrite(cout, buf, INITDAT-textsize);
 		textsize = INITDAT;
 	}
 
@@ -1080,7 +1080,7 @@ cflush(void)
 
 	n = sizeof(buf.cbuf) - cbc;
 	if(n)
-		write(cout, buf.cbuf, n);
+		ewrite(cout, buf.cbuf, n);
 	cbp = buf.cbuf;
 	cbc = sizeof(buf.cbuf);
 }
@@ -1213,7 +1213,7 @@ datblk(int32 s, int32 n, int32 rodata)
 		}
 	}
 
-	write(cout, buf.dbuf, n);
+	ewrite(cout, buf.dbuf, n);
 	if(!debug['a'])
 		return;
 

src/cmd/ld/elf.c

@@ -316,7 +316,7 @@ elfwriteinterp(void)
 
 	n = strlen(interp)+1;
 	seek(cout, ELFRESERVE-n, 0);
-	write(cout, interp, n);
+	ewrite(cout, interp, n);
 	return n;
 }
 

src/cmd/ld/lib.c

@@ -924,3 +924,12 @@ addsection(Segment *seg, char *name, int rwx)
 	*l = sect;
 	return sect;
 }
+
+void
+ewrite(int fd, void *buf, int n)
+{
+	if(write(fd, buf, n) < 0) {
+		diag("write error: %r");
+		errorexit();
+	}
+}

src/cmd/ld/lib.h

@@ -128,6 +128,7 @@ void	ldpkg(Biobuf*, char*, int64, char*, int);
 void	mark(Sym *s);
 char*	expandpkg(char*, char*);
 void	deadcode(void);
+void	ewrite(int, void*, int);
 
 int	pathchar(void);
 void*	mal(uint32);

src/cmd/ld/macho.c

@@ -430,8 +430,8 @@ domacholink(void)
 			}
 		}
 
-		write(cout, linkdata, nlinkdata);
-		write(cout, strtab, nstrtab);
+		ewrite(cout, linkdata, nlinkdata);
+		ewrite(cout, strtab, nstrtab);
 	}
 	return rnd(nlinkdata+nstrtab, INITRND);
 }

src/libmach/executable.c

@@ -786,7 +786,8 @@ error:
 			goto done;
 		memset(buf, 0, sizeof buf);
 		seek(fd, sh[ep->shstrndx].offset, 0);
-		read(fd, buf, sh[ep->shstrndx].size);
+		i = read(fd, buf, sh[ep->shstrndx].size);
+		USED(i);	// shut up ubuntu gcc
 
 		for(i = 0; i < ep->shnum; i++) {
 			if (strcmp(&buf[sh[i].name], ".gosymtab") == 0) {
@@ -967,7 +968,8 @@ error:
 			goto done;
 		memset(buf, 0, sizeof buf);
 		seek(fd, sh[ep->shstrndx].offset, 0);
-		read(fd, buf, sh[ep->shstrndx].size);
+		i = read(fd, buf, sh[ep->shstrndx].size);
+		USED(i);	// shut up ubuntu gcc
 
 		for(i = 0; i < ep->shnum; i++) {
 			if (strcmp(&buf[sh[i].name], ".gosymtab") == 0) {