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