file-copy.c revision fe363b433b8038a69b55169da9dca27892ad7d18
/* Copyright (c) 2006 Timo Sirainen */
#include "lib.h"
#include "istream.h"
#include "ostream.h"
#include "file-copy.h"
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
static int file_copy_to_tmp(const char *srcpath, const char *tmppath,
bool try_hardlink)
{
struct istream *input;
struct ostream *output;
struct stat st;
mode_t old_umask;
int fd_in, fd_out;
off_t ret;
if (try_hardlink) {
/* see if hardlinking works */
if (link(srcpath, tmppath) == 0)
return 1;
if (errno == EEXIST) {
if (unlink(tmppath) < 0 && errno != ENOENT) {
i_error("unlink(%s) failed: %m", tmppath);
return -1;
}
if (link(srcpath, tmppath) == 0)
return 1;
}
if (errno == ENOENT)
return 0;
if (!ECANTLINK(errno)) {
i_error("link(%s, %s) failed: %m", srcpath, tmppath);
return -1;
}
/* fallback to manual copying */
}
fd_in = open(srcpath, O_RDONLY);
if (fd_in == -1) {
if (errno == ENOENT)
return 0;
i_error("open(%s) failed: %m", srcpath);
return -1;
}
if (fstat(fd_in, &st) < 0) {
i_error("fstat(%s) failed: %m", srcpath);
(void)close(fd_in);
return -1;
}
old_umask = umask(0);
fd_out = open(tmppath, O_WRONLY | O_CREAT | O_TRUNC, st.st_mode);
umask(old_umask);
if (fd_out == -1) {
i_error("open(%s, O_CREAT) failed: %m", tmppath);
(void)close(fd_in);
return -1;
}
/* try to change the group, don't really care if it fails */
(void)fchown(fd_out, (uid_t)-1, st.st_gid);
input = i_stream_create_file(fd_in, 0, FALSE);
output = o_stream_create_file(fd_out, 0, FALSE);
while ((ret = o_stream_send_istream(output, input)) > 0) ;
i_stream_destroy(&input);
o_stream_destroy(&output);
if (close(fd_in) < 0) {
i_error("close(%s) failed: %m", srcpath);
ret = -1;
}
if (close(fd_out) < 0) {
i_error("close(%s) failed: %m", tmppath);
ret = -1;
}
return ret < 0 ? -1 : 1;
}
int file_copy(const char *srcpath, const char *destpath, bool try_hardlink)
{
const char *tmppath;
int ret;
t_push();
tmppath = t_strconcat(destpath, ".tmp", NULL);
ret = file_copy_to_tmp(srcpath, tmppath, try_hardlink);
if (ret > 0) {
if (rename(tmppath, destpath) < 0) {
i_error("rename(%s, %s) failed: %m", tmppath, destpath);
ret = -1;
}
}
if (ret < 0)
(void)unlink(tmppath);
t_pop();
return ret;
}