ioexact.c

   1 #include <errno.h>
   2 #include <unistd.h>
   3 #include <signal.h>
   4
   5 #include "ioexact.h"
   6
   7 extern volatile sig_atomic_t sigint;
   8
   9 ssize_t read_exact(int fd, void *buf, size_t len, int mayexit)
  10 {
  11         ssize_t num = 0, written;
  12
  13         while (len > 0 && !sigint) {
  14                 if ((written = read(fd, buf, len)) < 0) {
  15                         if (errno == EAGAIN && num > 0)
  16                                 continue;
  17                         if (mayexit)
  18                                 return -1;
  19                         else
  20                                 continue;
  21                 }
  22                 if (!written)
  23                         return 0;
  24                 len -= written;
  25                 buf += written;
  26                 num += written;
  27         }
  28
  29         return num;
  30 }
  31
  32 ssize_t write_exact(int fd, void *buf, size_t len, int mayexit)
  33 {
  34         ssize_t num = 0, written;
  35
  36         while (len > 0 && !sigint) {
  37                 if ((written = write(fd, buf, len)) < 0) {
  38                         if (errno == EAGAIN && num > 0)
  39                                 continue;
  40                         if (mayexit)
  41                                 return -1;
  42                         else
  43                                 continue;
  44                 }
  45                 if (!written)
  46                         return 0;
  47                 len -= written;
  48                 buf += written;
  49                 num += written;
  50         }
  51
  52         return num;
  53 }