copy.c

   1 #include "cache.h"
   2
   3 int copy_fd(int ifd, int ofd)
   4 {
   5         while (1) {
   6                 int len;
   7                 char buffer[8192];
   8                 char *buf = buffer;
   9                 len = read(ifd, buffer, sizeof(buffer));
  10                 if (!len)
  11                         break;
  12                 if (len < 0) {
  13                         int read_error;
  14                         if (errno == EAGAIN)
  15                                 continue;
  16                         read_error = errno;
  17                         close(ifd);
  18                         return error("copy-fd: read returned %s",
  19                                      strerror(read_error));
  20                 }
  21                 while (1) {
  22                         int written = write(ofd, buf, len);
  23                         if (written > 0) {
  24                                 buf += written;
  25                                 len -= written;
  26                                 if (!len)
  27                                         break;
  28                         }
  29                         if (!written)
  30                                 return error("copy-fd: write returned 0");
  31                         if (errno == EAGAIN || errno == EINTR)
  32                                 continue;
  33                         return error("copy-fd: write returned %s",
  34                                      strerror(errno));
  35                 }
  36         }
  37         close(ifd);
  38         return 0;
  39 }
  40