copy.c

   1 #include "cache.h"
   2
   3 int copy_fd(int ifd, int ofd)
   4 {
   5         while (1) {
   6                 char buffer[8192];
   7                 char *buf = buffer;
   8                 ssize_t len = xread(ifd, buffer, sizeof(buffer));
   9                 if (!len)
  10                         break;
  11                 if (len < 0) {
  12                         int read_error = errno;
  13                         close(ifd);
  14                         return error("copy-fd: read returned %s",
  15                                      strerror(read_error));
  16                 }
  17                 while (len) {
  18                         int written = xwrite(ofd, buf, len);
  19                         if (written > 0) {
  20                                 buf += written;
  21                                 len -= written;
  22                         }
  23                         else if (!written) {
  24                                 close(ifd);
  25                                 return error("copy-fd: write returned 0");
  26                         } else {
  27                                 int write_error = errno;
  28                                 close(ifd);
  29                                 return error("copy-fd: write returned %s",
  30                                              strerror(write_error));
  31                         }
  32                 }
  33         }
  34         close(ifd);
  35         return 0;
  36 }
  37
  38 int copy_file(const char *dst, const char *src, int mode)
  39 {
  40         int fdi, fdo, status;
  41
  42         mode = (mode & 0111) ? 0777 : 0666;
  43         if ((fdi = open(src, O_RDONLY)) < 0)
  44                 return fdi;
  45         if ((fdo = open(dst, O_WRONLY | O_CREAT | O_EXCL, mode)) < 0) {
  46                 close(fdi);
  47                 return fdo;
  48         }
  49         status = copy_fd(fdi, fdo);
  50         if (close(fdo) != 0)
  51                 return error("%s: close error: %s", dst, strerror(errno));
  52
  53         if (!status && adjust_shared_perm(dst))
  54                 return -1;
  55
  56         return status;
  57 }