freebsd-dev/bin/cat/cat.c
Ivan Voras e9cbc9a770 Teach cat(1) and cp(1) to use a larger buffer if enough memory is present
in the system. A simple heuristics is used to detect what is "enough"
memory: if number of physmem pages is greater than 32k (equalling 128 MB
on machines with 4 kB pages).

Typical immediate result of these changes is reduction in context switches
and the goal is to increase efficiency by using large buffers:
before: /usr/bin/time -hlp cat file1 > file2
...
       163  voluntary context switches
     11194  involuntary context switches
after: /usr/bin/time -hlp ./cat file1 > file2
...
       417  voluntary context switches
       272  involuntary context switches

Reviewed by:    hackers@ (no objections to earlier version of cat patch)
Approved by:    gnn (mentor)
MFC after:      4 months
2008-10-30 14:05:57 +00:00

334 lines
7.3 KiB
C

/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kevin Fall.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if 0
#ifndef lint
static char const copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#endif
#ifndef lint
#if 0
static char sccsid[] = "@(#)cat.c 8.2 (Berkeley) 4/27/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/stat.h>
#ifndef NO_UDOM_SUPPORT
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#endif
#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stddef.h>
int bflag, eflag, nflag, sflag, tflag, vflag;
int rval;
const char *filename;
static void usage(void);
static void scanfiles(char *argv[], int cooked);
static void cook_cat(FILE *);
static void raw_cat(int);
#ifndef NO_UDOM_SUPPORT
static int udom_open(const char *path, int flags);
#endif
/* Memory strategy threshold, in pages: if physmem is larger then this, use a
* large buffer */
#define PHYSPAGES_THRESHOLD (32*1024)
/* Maximum buffer size in bytes - do not allow it to grow larger than this */
#define BUFSIZE_MAX (2*1024*1024)
/* Small (default) buffer size in bytes. It's inefficient for this to be
* smaller than MAXPHYS */
#define BUFSIZE_SMALL (MAXPHYS)
int
main(int argc, char *argv[])
{
int ch;
setlocale(LC_CTYPE, "");
while ((ch = getopt(argc, argv, "benstuv")) != -1)
switch (ch) {
case 'b':
bflag = nflag = 1; /* -b implies -n */
break;
case 'e':
eflag = vflag = 1; /* -e implies -v */
break;
case 'n':
nflag = 1;
break;
case 's':
sflag = 1;
break;
case 't':
tflag = vflag = 1; /* -t implies -v */
break;
case 'u':
setbuf(stdout, NULL);
break;
case 'v':
vflag = 1;
break;
default:
usage();
}
argv += optind;
if (bflag || eflag || nflag || sflag || tflag || vflag)
scanfiles(argv, 1);
else
scanfiles(argv, 0);
if (fclose(stdout))
err(1, "stdout");
exit(rval);
/* NOTREACHED */
}
static void
usage(void)
{
fprintf(stderr, "usage: cat [-benstuv] [file ...]\n");
exit(1);
/* NOTREACHED */
}
static void
scanfiles(char *argv[], int cooked)
{
int i = 0;
char *path;
FILE *fp;
while ((path = argv[i]) != NULL || i == 0) {
int fd;
if (path == NULL || strcmp(path, "-") == 0) {
filename = "stdin";
fd = STDIN_FILENO;
} else {
filename = path;
fd = open(path, O_RDONLY);
#ifndef NO_UDOM_SUPPORT
if (fd < 0 && errno == EOPNOTSUPP)
fd = udom_open(path, O_RDONLY);
#endif
}
if (fd < 0) {
warn("%s", path);
rval = 1;
} else if (cooked) {
if (fd == STDIN_FILENO)
cook_cat(stdin);
else {
fp = fdopen(fd, "r");
cook_cat(fp);
fclose(fp);
}
} else {
raw_cat(fd);
if (fd != STDIN_FILENO)
close(fd);
}
if (path == NULL)
break;
++i;
}
}
static void
cook_cat(FILE *fp)
{
int ch, gobble, line, prev;
/* Reset EOF condition on stdin. */
if (fp == stdin && feof(stdin))
clearerr(stdin);
line = gobble = 0;
for (prev = '\n'; (ch = getc(fp)) != EOF; prev = ch) {
if (prev == '\n') {
if (sflag) {
if (ch == '\n') {
if (gobble)
continue;
gobble = 1;
} else
gobble = 0;
}
if (nflag && (!bflag || ch != '\n')) {
(void)fprintf(stdout, "%6d\t", ++line);
if (ferror(stdout))
break;
}
}
if (ch == '\n') {
if (eflag && putchar('$') == EOF)
break;
} else if (ch == '\t') {
if (tflag) {
if (putchar('^') == EOF || putchar('I') == EOF)
break;
continue;
}
} else if (vflag) {
if (!isascii(ch) && !isprint(ch)) {
if (putchar('M') == EOF || putchar('-') == EOF)
break;
ch = toascii(ch);
}
if (iscntrl(ch)) {
if (putchar('^') == EOF ||
putchar(ch == '\177' ? '?' :
ch | 0100) == EOF)
break;
continue;
}
}
if (putchar(ch) == EOF)
break;
}
if (ferror(fp)) {
warn("%s", filename);
rval = 1;
clearerr(fp);
}
if (ferror(stdout))
err(1, "stdout");
}
static void
raw_cat(int rfd)
{
int off, wfd;
ssize_t nr, nw;
static size_t bsize;
static char *buf = NULL;
struct stat sbuf;
wfd = fileno(stdout);
if (buf == NULL) {
if (fstat(wfd, &sbuf))
err(1, "%s", filename);
if (S_ISREG(sbuf.st_mode)) {
/* If there's plenty of RAM, use a large copy buffer */
if (sysconf(_SC_PHYS_PAGES) > PHYSPAGES_THRESHOLD)
bsize = MIN(BUFSIZE_MAX, MAXPHYS*8);
else
bsize = BUFSIZE_SMALL;
} else
bsize = MAX(sbuf.st_blksize,
(blksize_t)sysconf(_SC_PAGESIZE));
if ((buf = malloc(bsize)) == NULL)
err(1, "malloc() failure of IO buffer");
}
while ((nr = read(rfd, buf, bsize)) > 0)
for (off = 0; nr; nr -= nw, off += nw)
if ((nw = write(wfd, buf + off, (size_t)nr)) < 0)
err(1, "stdout");
if (nr < 0) {
warn("%s", filename);
rval = 1;
}
}
#ifndef NO_UDOM_SUPPORT
static int
udom_open(const char *path, int flags)
{
struct sockaddr_un sou;
int fd;
unsigned int len;
bzero(&sou, sizeof(sou));
/*
* Construct the unix domain socket address and attempt to connect
*/
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd >= 0) {
sou.sun_family = AF_UNIX;
if ((len = strlcpy(sou.sun_path, path,
sizeof(sou.sun_path))) >= sizeof(sou.sun_path)) {
errno = ENAMETOOLONG;
return (-1);
}
len = offsetof(struct sockaddr_un, sun_path[len+1]);
if (connect(fd, (void *)&sou, len) < 0) {
close(fd);
fd = -1;
}
}
/*
* handle the open flags by shutting down appropriate directions
*/
if (fd >= 0) {
switch(flags & O_ACCMODE) {
case O_RDONLY:
if (shutdown(fd, SHUT_WR) == -1)
warn(NULL);
break;
case O_WRONLY:
if (shutdown(fd, SHUT_RD) == -1)
warn(NULL);
break;
default:
break;
}
}
return(fd);
}
#endif