cat(1) sizes its I/O buffer according to the st_blksize of the first
file it processes. We don't do this very often in the tree. I'm not
sure if we should trust st_blksize.
It would be simpler to just choose a value that works in practice and
always use it.
64K works well. We settled on that for tee(1) recently.
Thoughts?
Index: cat.c
===================================================================
RCS file: /cvs/src/bin/cat/cat.c,v
retrieving revision 1.32
diff -u -p -r1.32 cat.c
--- cat.c 24 Oct 2021 21:24:21 -0000 1.32
+++ cat.c 13 Dec 2021 00:57:48 -0000
@@ -33,9 +33,6 @@
* SUCH DAMAGE.
*/
-#include <sys/types.h>
-#include <sys/stat.h>
-
#include <ctype.h>
#include <err.h>
#include <errno.h>
@@ -45,7 +42,7 @@
#include <string.h>
#include <unistd.h>
-#define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
+#define BSIZE (64 * 1024)
int bflag, eflag, nflag, sflag, tflag, vflag;
int rval;
@@ -221,26 +218,20 @@ raw_args(char **argv)
void
raw_cat(int rfd, const char *filename)
{
- int wfd;
+ char *buf;
ssize_t nr, nw, off;
- static size_t bsize;
- static char *buf = NULL;
- struct stat sbuf;
+ int wfd;
wfd = fileno(stdout);
- if (buf == NULL) {
- if (fstat(wfd, &sbuf) == -1)
- err(1, "stdout");
- bsize = MAXIMUM(sbuf.st_blksize, BUFSIZ);
- if ((buf = malloc(bsize)) == NULL)
- err(1, NULL);
- }
- while ((nr = read(rfd, buf, bsize)) != -1 && nr != 0) {
+ if ((buf = malloc(BSIZE)) == NULL)
+ err(1, NULL);
+ while ((nr = read(rfd, buf, BSIZE)) != -1 && nr != 0) {
for (off = 0; nr; nr -= nw, off += nw) {
if ((nw = write(wfd, buf + off, nr)) == -1 || nw == 0)
err(1, "stdout");
}
}
+ free(buf);
if (nr == -1) {
warn("%s", filename);
rval = 1;
