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// SPDX-License-Identifier: GPL-2.0
#include "util/copyfile.h"
#include "util/namespaces.h"
#include <internal/lib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static int slow_copyfile(const char *from, const char *to, struct nsinfo *nsi)
{
int err = -1;
char *line = NULL;
size_t n;
FILE *from_fp, *to_fp;
struct nscookie nsc;
nsinfo__mountns_enter(nsi, &nsc);
from_fp = fopen(from, "r");
nsinfo__mountns_exit(&nsc);
if (from_fp == NULL)
goto out;
to_fp = fopen(to, "w");
if (to_fp == NULL)
goto out_fclose_from;
while (getline(&line, &n, from_fp) > 0)
if (fputs(line, to_fp) == EOF)
goto out_fclose_to;
err = 0;
out_fclose_to:
fclose(to_fp);
free(line);
out_fclose_from:
fclose(from_fp);
out:
return err;
}
int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64 size)
{
void *ptr;
loff_t pgoff;
pgoff = off_in & ~(page_size - 1);
off_in -= pgoff;
ptr = mmap(NULL, off_in + size, PROT_READ, MAP_PRIVATE, ifd, pgoff);
if (ptr == MAP_FAILED)
return -1;
while (size) {
ssize_t ret = pwrite(ofd, ptr + off_in, size, off_out);
if (ret < 0 && errno == EINTR)
continue;
if (ret <= 0)
break;
size -= ret;
off_in += ret;
off_out += ret;
}
munmap(ptr, off_in + size);
return size ? -1 : 0;
}
static int copyfile_mode_ns(const char *from, const char *to, mode_t mode,
struct nsinfo *nsi)
{
int fromfd, tofd;
struct stat st;
int err;
char *tmp = NULL, *ptr = NULL;
struct nscookie nsc;
nsinfo__mountns_enter(nsi, &nsc);
err = stat(from, &st);
nsinfo__mountns_exit(&nsc);
if (err)
goto out;
err = -1;
/* extra 'x' at the end is to reserve space for '.' */
if (asprintf(&tmp, "%s.XXXXXXx", to) < 0) {
tmp = NULL;
goto out;
}
ptr = strrchr(tmp, '/');
if (!ptr)
goto out;
ptr = memmove(ptr + 1, ptr, strlen(ptr) - 1);
*ptr = '.';
tofd = mkstemp(tmp);
if (tofd < 0)
goto out;
if (fchmod(tofd, mode))
goto out_close_to;
if (st.st_size == 0) { /* /proc? do it slowly... */
err = slow_copyfile(from, tmp, nsi);
goto out_close_to;
}
nsinfo__mountns_enter(nsi, &nsc);
fromfd = open(from, O_RDONLY);
nsinfo__mountns_exit(&nsc);
if (fromfd < 0)
goto out_close_to;
err = copyfile_offset(fromfd, 0, tofd, 0, st.st_size);
close(fromfd);
out_close_to:
close(tofd);
if (!err)
err = link(tmp, to);
unlink(tmp);
out:
free(tmp);
return err;
}
int copyfile_ns(const char *from, const char *to, struct nsinfo *nsi)
{
return copyfile_mode_ns(from, to, 0755, nsi);
}
int copyfile_mode(const char *from, const char *to, mode_t mode)
{
return copyfile_mode_ns(from, to, mode, NULL);
}
int copyfile(const char *from, const char *to)
{
return copyfile_mode(from, to, 0755);
}
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