upstream: If write() returned short, the subsequent write would restart

daztucker · djmdjm · commit b9a640a1a0dc · 2025-10-06T12:18:53.000+11:00
from the beginning of the buffer not the end of what was written.  Fix, since
we want modpipe to corrupt data for testing purposes deliberately not
accidentally.  ok djm@

OpenBSD-Regress-ID: 50ca74d287445c58944f070bb92dc13b1d054b43
diff --git a/regress/modpipe.c b/regress/modpipe.c
@@ -14,7 +14,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $OpenBSD: modpipe.c,v 1.6 2013/11/21 03:16:47 djm Exp $ */
+/* $OpenBSD: modpipe.c,v 1.7 2025/10/03 01:03:45 dtucker Exp $ */
 
 #include "includes.h"
 
@@ -127,7 +127,7 @@ main(int argc, char **argv)
 			}
 		}
 		for (o = 0; o < s; o += r) {
-			r = write(STDOUT_FILENO, buf, s - o);
+			r = write(STDOUT_FILENO, buf + o, s - o);
 			if (r == 0)
 				break;
 			if (r < 0) {

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@`
`14`	`14`	`* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.`
`15`	`15`	`*/`
`16`	`16`
`17`		`-/* $OpenBSD: modpipe.c,v 1.6 2013/11/21 03:16:47 djm Exp $ */`
	`17`	`+/* $OpenBSD: modpipe.c,v 1.7 2025/10/03 01:03:45 dtucker Exp $ */`
`18`	`18`
`19`	`19`	`#include "includes.h"`
`20`	`20`
`@@ -127,7 +127,7 @@ main(int argc, char **argv)`
`127`	`127`	`}`
`128`	`128`	`}`
`129`	`129`	`for (o = 0; o < s; o += r) {`
`130`		`- r = write(STDOUT_FILENO, buf, s - o);`
	`130`	`+ r = write(STDOUT_FILENO, buf + o, s - o);`
`131`	`131`	`if (r == 0)`
`132`	`132`	`break;`
`133`	`133`	`if (r < 0) {`