Re: io_write()/fwrite() and EINTR on Solaris

Hi,

At Fri, 8 Nov 2002 03:16:50 +0900,
Jos Backus wrote:
> Hm, the return value of the fwrite() call in w_byten() is not checked at all,
> that seems to be a potential troublespot to me.  Perhaps move the fwrite()
> wrapper into its own function (rb_safe_write()?) and call it in both places
> instead?

Perhaps, rb_io_fwrite()?

I'm not sure BROKEN_FWRITE is better or not.


Index: io.c
===================================================================
RCS file: /cvs/ruby/src/ruby/io.c,v
retrieving revision 1.167
diff -u -2 -p -r1.167 io.c
--- io.c	29 Oct 2002 21:35:28 -0000	1.167
+++ io.c	8 Nov 2002 01:34:58 -0000
@@ -25,5 +25,9 @@
 #include <errno.h>
 
+#ifdef BROKEN_FWRITE
+# include <signal.h>
+#endif
+
 #if defined(MSDOS) || defined(__BOW__) || defined(__CYGWIN__) || defined(NT) || defined(__human68k__) || defined(__EMX__) || defined(__BEOS__)
 # define NO_SAFE_RENAME
@@ -352,4 +356,76 @@ rb_io_wait_writable(f)
 
 /* writing functions */
+#ifdef BROKEN_FWRITE
+# ifdef HAVE_SIGPROCMASK
+static sigset_t fwrite_mask;
+#   define Init_fwrite() (sigemptyset(&fwrite_mask), sigaddset(&fwrite_mask, SIGVTALRM))
+# else
+#   define Init_fwrite() (void)0
+# endif
+
+static int
+safe_fwrite(ptr, size, len, f)
+    const void *ptr;
+    int size, len;
+    FILE *f;
+{
+    int n;
+# ifdef HAVE_SIGPROCMASK
+    sigset_t set;
+    sigprocmask(SIG_BLOCK, &fwrite_mask, &set);
+# else
+    int mask = siggetmask();
+    sigblock(sigmask(SIGVTALRM));
+# endif
+
+    n = fwrite(ptr, size, len, f);
+
+# ifdef HAVE_SIGPROCMASK
+    sigprocmask(SIG_UNBLOCK, &set, 0);
+# else
+    sigsetmask(mask);
+# endif
+    return n;
+}
+
+#else
+# define safe_fwrite(p, n, f) fwrite((p), 1, (n), (f))
+#endif
+
+long
+rb_io_fwrite(ptr, len, f)
+    const char *ptr;
+    long len;
+    FILE *f;
+{
+    long n, r;
+
+    if ((n = len) <= 0) return n;
+#if defined(__human68k__) || defined(sun)
+    do {
+	if (fputc(*ptr, f) == EOF) {
+	    if (!ferror(f)) break;
+	    if (rb_io_wait_writable(fileno(f))) {
+		clearerr(f);
+		continue;
+	    }
+	    return -1L;
+	}
+	p++;
+    } while (--n > 0);
+#else
+    while (ptr += (r = safe_fwrite(ptr, n, f)), (n -= r) > 0) {
+	if (ferror(f)) {
+	    if (rb_io_wait_writable(fileno(f))) {
+		clearerr(f);
+		continue;
+	    }
+	    return -1L;
+	}
+    }
+#endif
+    return len - n;
+}
+
 static VALUE
 io_write(io, str)
@@ -358,6 +434,5 @@ io_write(io, str)
     OpenFile *fptr;
     FILE *f;
-    long n, r;
-    register char *ptr;
+    long n;
 
     rb_secure(4);
@@ -375,25 +450,6 @@ io_write(io, str)
     f = GetWriteFile(fptr);
 
-    ptr = RSTRING(str)->ptr;
-    n = RSTRING(str)->len;
-#ifdef __human68k__
-    do {
-	if (fputc(*ptr++, f) == EOF) {
-	    if (ferror(f)) rb_sys_fail(fptr->path);
-	    break;
-	}
-    } while (--n > 0);
-#else
-    while (ptr += (r = fwrite(ptr, 1, n, f)), (n -= r) > 0) {
-	if (ferror(f)) {
-	    if (rb_io_wait_writable(fileno(f))) {
-		clearerr(f);
-		continue;
-	    }
-	    rb_sys_fail(fptr->path);
-	}
-    }
-#endif
-    n = ptr - RSTRING(str)->ptr;
+    n = rb_io_fwrite(RSTRING(str)->ptr, RSTRING(str)->len, f);
+    if (n == -1L) rb_sys_fail(fptr->path);
     if (fptr->mode & FMODE_SYNC) {
 	io_fflush(f, fptr);
Index: marshal.c
===================================================================
RCS file: /cvs/ruby/src/ruby/marshal.c,v
retrieving revision 1.73
diff -u -2 -p -r1.73 marshal.c
--- marshal.c	17 Oct 2002 10:20:52 -0000	1.73
+++ marshal.c	8 Nov 2002 01:33:38 -0000
@@ -103,5 +103,6 @@ w_byten(s, n, arg)
 {
     if (arg->fp) {
-	fwrite(s, 1, n, arg->fp);
+	if (rb_io_fwrite(s, n, arg->fp) < 0)
+	    rb_sys_fail(0);
     }
     else {
Index: rubyio.h
===================================================================
RCS file: /cvs/ruby/src/ruby/rubyio.h,v
retrieving revision 1.20
diff -u -2 -p -r1.20 rubyio.h
--- rubyio.h	2 Oct 2002 14:59:25 -0000	1.20
+++ rubyio.h	8 Nov 2002 01:31:21 -0000
@@ -60,4 +60,5 @@ FILE *rb_fdopen _((int, const char*));
 int rb_getc _((FILE*));
 long rb_io_fread _((char *, long, FILE *));
+long rb_io_fwrite _((const char *, long, FILE *));
 int  rb_io_mode_flags _((const char*));
 void rb_io_check_writable _((OpenFile*));


-- 
Nobu Nakada