freebsd-skq/bin/cp/utils.c
ivoras 1f332d86bf 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

463 lines
12 KiB
C

/*-
* Copyright (c) 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)utils.c 8.3 (Berkeley) 4/1/94";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/acl.h>
#include <sys/param.h>
#include <sys/stat.h>
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
#include <sys/mman.h>
#endif
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fts.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
#include <unistd.h>
#include "extern.h"
#define cp_pct(x, y) ((y == 0) ? 0 : (int)(100.0 * (x) / (y)))
/* 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
copy_file(const FTSENT *entp, int dne)
{
static char *buf = NULL;
static size_t bufsize;
struct stat *fs;
ssize_t wcount;
size_t wresid;
off_t wtotal;
int ch, checkch, from_fd = 0, rcount, rval, to_fd = 0;
char *bufp;
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
char *p;
#endif
if ((from_fd = open(entp->fts_path, O_RDONLY, 0)) == -1) {
warn("%s", entp->fts_path);
return (1);
}
fs = entp->fts_statp;
/*
* If the file exists and we're interactive, verify with the user.
* If the file DNE, set the mode to be the from file, minus setuid
* bits, modified by the umask; arguably wrong, but it makes copying
* executables work right and it's been that way forever. (The
* other choice is 666 or'ed with the execute bits on the from file
* modified by the umask.)
*/
if (!dne) {
#define YESNO "(y/n [n]) "
if (nflag) {
if (vflag)
printf("%s not overwritten\n", to.p_path);
(void)close(from_fd);
return (0);
} else if (iflag) {
(void)fprintf(stderr, "overwrite %s? %s",
to.p_path, YESNO);
checkch = ch = getchar();
while (ch != '\n' && ch != EOF)
ch = getchar();
if (checkch != 'y' && checkch != 'Y') {
(void)close(from_fd);
(void)fprintf(stderr, "not overwritten\n");
return (1);
}
}
if (fflag) {
/* remove existing destination file name,
* create a new file */
(void)unlink(to.p_path);
if (!lflag)
to_fd = open(to.p_path, O_WRONLY | O_TRUNC | O_CREAT,
fs->st_mode & ~(S_ISUID | S_ISGID));
} else {
if (!lflag)
/* overwrite existing destination file name */
to_fd = open(to.p_path, O_WRONLY | O_TRUNC, 0);
}
} else {
if (!lflag)
to_fd = open(to.p_path, O_WRONLY | O_TRUNC | O_CREAT,
fs->st_mode & ~(S_ISUID | S_ISGID));
}
if (to_fd == -1) {
warn("%s", to.p_path);
(void)close(from_fd);
return (1);
}
rval = 0;
if (!lflag) {
/*
* Mmap and write if less than 8M (the limit is so we don't totally
* trash memory on big files. This is really a minor hack, but it
* wins some CPU back.
* Some filesystems, such as smbnetfs, don't support mmap,
* so this is a best-effort attempt.
*/
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
if (S_ISREG(fs->st_mode) && fs->st_size > 0 &&
fs->st_size <= 8 * 1024 * 1024 &&
(p = mmap(NULL, (size_t)fs->st_size, PROT_READ,
MAP_SHARED, from_fd, (off_t)0)) != MAP_FAILED) {
wtotal = 0;
for (bufp = p, wresid = fs->st_size; ;
bufp += wcount, wresid -= (size_t)wcount) {
wcount = write(to_fd, bufp, wresid);
if (wcount <= 0)
break;
wtotal += wcount;
if (info) {
info = 0;
(void)fprintf(stderr,
"%s -> %s %3d%%\n",
entp->fts_path, to.p_path,
cp_pct(wtotal, fs->st_size));
}
if (wcount >= (ssize_t)wresid)
break;
}
if (wcount != (ssize_t)wresid) {
warn("%s", to.p_path);
rval = 1;
}
/* Some systems don't unmap on close(2). */
if (munmap(p, fs->st_size) < 0) {
warn("%s", entp->fts_path);
rval = 1;
}
} else
#endif
{
if (buf == NULL) {
/*
* Note that buf and bufsize are static. If
* malloc() fails, it will fail at the start
* and not copy only some files.
*/
if (sysconf(_SC_PHYS_PAGES) >
PHYSPAGES_THRESHOLD)
bufsize = MIN(BUFSIZE_MAX, MAXPHYS * 8);
else
bufsize = BUFSIZE_SMALL;
buf = malloc(bufsize);
if (buf == NULL)
err(1, "Not enough memory");
}
wtotal = 0;
while ((rcount = read(from_fd, buf, bufsize)) > 0) {
for (bufp = buf, wresid = rcount; ;
bufp += wcount, wresid -= wcount) {
wcount = write(to_fd, bufp, wresid);
if (wcount <= 0)
break;
wtotal += wcount;
if (info) {
info = 0;
(void)fprintf(stderr,
"%s -> %s %3d%%\n",
entp->fts_path, to.p_path,
cp_pct(wtotal, fs->st_size));
}
if (wcount >= (ssize_t)wresid)
break;
}
if (wcount != (ssize_t)wresid) {
warn("%s", to.p_path);
rval = 1;
break;
}
}
if (rcount < 0) {
warn("%s", entp->fts_path);
rval = 1;
}
}
} else {
if (link(entp->fts_path, to.p_path)) {
warn("%s", to.p_path);
rval = 1;
}
}
/*
* Don't remove the target even after an error. The target might
* not be a regular file, or its attributes might be important,
* or its contents might be irreplaceable. It would only be safe
* to remove it if we created it and its length is 0.
*/
if (!lflag) {
if (pflag && setfile(fs, to_fd))
rval = 1;
if (pflag && preserve_fd_acls(from_fd, to_fd) != 0)
rval = 1;
if (close(to_fd)) {
warn("%s", to.p_path);
rval = 1;
}
}
(void)close(from_fd);
return (rval);
}
int
copy_link(const FTSENT *p, int exists)
{
int len;
char llink[PATH_MAX];
if ((len = readlink(p->fts_path, llink, sizeof(llink) - 1)) == -1) {
warn("readlink: %s", p->fts_path);
return (1);
}
llink[len] = '\0';
if (exists && unlink(to.p_path)) {
warn("unlink: %s", to.p_path);
return (1);
}
if (symlink(llink, to.p_path)) {
warn("symlink: %s", llink);
return (1);
}
return (pflag ? setfile(p->fts_statp, -1) : 0);
}
int
copy_fifo(struct stat *from_stat, int exists)
{
if (exists && unlink(to.p_path)) {
warn("unlink: %s", to.p_path);
return (1);
}
if (mkfifo(to.p_path, from_stat->st_mode)) {
warn("mkfifo: %s", to.p_path);
return (1);
}
return (pflag ? setfile(from_stat, -1) : 0);
}
int
copy_special(struct stat *from_stat, int exists)
{
if (exists && unlink(to.p_path)) {
warn("unlink: %s", to.p_path);
return (1);
}
if (mknod(to.p_path, from_stat->st_mode, from_stat->st_rdev)) {
warn("mknod: %s", to.p_path);
return (1);
}
return (pflag ? setfile(from_stat, -1) : 0);
}
int
setfile(struct stat *fs, int fd)
{
static struct timeval tv[2];
struct stat ts;
int rval, gotstat, islink, fdval;
rval = 0;
fdval = fd != -1;
islink = !fdval && S_ISLNK(fs->st_mode);
fs->st_mode &= S_ISUID | S_ISGID | S_ISVTX |
S_IRWXU | S_IRWXG | S_IRWXO;
TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atimespec);
TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtimespec);
if (islink ? lutimes(to.p_path, tv) : utimes(to.p_path, tv)) {
warn("%sutimes: %s", islink ? "l" : "", to.p_path);
rval = 1;
}
if (fdval ? fstat(fd, &ts) :
(islink ? lstat(to.p_path, &ts) : stat(to.p_path, &ts)))
gotstat = 0;
else {
gotstat = 1;
ts.st_mode &= S_ISUID | S_ISGID | S_ISVTX |
S_IRWXU | S_IRWXG | S_IRWXO;
}
/*
* Changing the ownership probably won't succeed, unless we're root
* or POSIX_CHOWN_RESTRICTED is not set. Set uid/gid before setting
* the mode; current BSD behavior is to remove all setuid bits on
* chown. If chown fails, lose setuid/setgid bits.
*/
if (!gotstat || fs->st_uid != ts.st_uid || fs->st_gid != ts.st_gid)
if (fdval ? fchown(fd, fs->st_uid, fs->st_gid) :
(islink ? lchown(to.p_path, fs->st_uid, fs->st_gid) :
chown(to.p_path, fs->st_uid, fs->st_gid))) {
if (errno != EPERM) {
warn("chown: %s", to.p_path);
rval = 1;
}
fs->st_mode &= ~(S_ISUID | S_ISGID);
}
if (!gotstat || fs->st_mode != ts.st_mode)
if (fdval ? fchmod(fd, fs->st_mode) :
(islink ? lchmod(to.p_path, fs->st_mode) :
chmod(to.p_path, fs->st_mode))) {
warn("chmod: %s", to.p_path);
rval = 1;
}
if (!gotstat || fs->st_flags != ts.st_flags)
if (fdval ?
fchflags(fd, fs->st_flags) :
(islink ? (errno = ENOSYS) :
chflags(to.p_path, fs->st_flags))) {
warn("chflags: %s", to.p_path);
rval = 1;
}
return (rval);
}
int
preserve_fd_acls(int source_fd, int dest_fd)
{
struct acl *aclp;
acl_t acl;
if (fpathconf(source_fd, _PC_ACL_EXTENDED) != 1 ||
fpathconf(dest_fd, _PC_ACL_EXTENDED) != 1)
return (0);
acl = acl_get_fd(source_fd);
if (acl == NULL) {
warn("failed to get acl entries while setting %s", to.p_path);
return (1);
}
aclp = &acl->ats_acl;
if (aclp->acl_cnt == 3)
return (0);
if (acl_set_fd(dest_fd, acl) < 0) {
warn("failed to set acl entries for %s", to.p_path);
return (1);
}
return (0);
}
int
preserve_dir_acls(struct stat *fs, char *source_dir, char *dest_dir)
{
acl_t (*aclgetf)(const char *, acl_type_t);
int (*aclsetf)(const char *, acl_type_t, acl_t);
struct acl *aclp;
acl_t acl;
if (pathconf(source_dir, _PC_ACL_EXTENDED) != 1 ||
pathconf(dest_dir, _PC_ACL_EXTENDED) != 1)
return (0);
/*
* If the file is a link we will not follow it
*/
if (S_ISLNK(fs->st_mode)) {
aclgetf = acl_get_link_np;
aclsetf = acl_set_link_np;
} else {
aclgetf = acl_get_file;
aclsetf = acl_set_file;
}
/*
* Even if there is no ACL_TYPE_DEFAULT entry here, a zero
* size ACL will be returned. So it is not safe to simply
* check the pointer to see if the default ACL is present.
*/
acl = aclgetf(source_dir, ACL_TYPE_DEFAULT);
if (acl == NULL) {
warn("failed to get default acl entries on %s",
source_dir);
return (1);
}
aclp = &acl->ats_acl;
if (aclp->acl_cnt != 0 && aclsetf(dest_dir,
ACL_TYPE_DEFAULT, acl) < 0) {
warn("failed to set default acl entries on %s",
dest_dir);
return (1);
}
acl = aclgetf(source_dir, ACL_TYPE_ACCESS);
if (acl == NULL) {
warn("failed to get acl entries on %s", source_dir);
return (1);
}
aclp = &acl->ats_acl;
if (aclsetf(dest_dir, ACL_TYPE_ACCESS, acl) < 0) {
warn("failed to set acl entries on %s", dest_dir);
return (1);
}
return (0);
}
void
usage(void)
{
(void)fprintf(stderr, "%s\n%s\n",
"usage: cp [-R [-H | -L | -P]] [-f | -i | -n] [-alpv] source_file target_file",
" cp [-R [-H | -L | -P]] [-f | -i | -n] [-alpv] source_file ... "
"target_directory");
exit(EX_USAGE);
}