write_or_die.c

   1 #include "cache.h"
   2
   3 /*
   4  * Some cases use stdio, but want to flush after the write
   5  * to get error handling (and to get better interactive
   6  * behaviour - not buffering excessively).
   7  *
   8  * Of course, if the flush happened within the write itself,
   9  * we've already lost the error code, and cannot report it any
  10  * more. So we just ignore that case instead (and hope we get
  11  * the right error code on the flush).
  12  *
  13  * If the file handle is stdout, and stdout is a file, then skip the
  14  * flush entirely since it's not needed.
  15  */
  16 void maybe_flush_or_die(FILE *f, const char *desc)
  17 {
  18         static int skip_stdout_flush = -1;
  19         struct stat st;
  20         char *cp;
  21
  22         if (f == stdout) {
  23                 if (skip_stdout_flush < 0) {
  24                         cp = getenv("GIT_FLUSH");
  25                         if (cp)
  26                                 skip_stdout_flush = (atoi(cp) == 0);
  27                         else if ((fstat(fileno(stdout), &st) == 0) &&
  28                                  S_ISREG(st.st_mode))
  29                                 skip_stdout_flush = 1;
  30                         else
  31                                 skip_stdout_flush = 0;
  32                 }
  33                 if (skip_stdout_flush && !ferror(f))
  34                         return;
  35         }
  36         if (fflush(f)) {
  37 #ifndef __MINGW32__
  38                 if (errno == EPIPE)
  39 #else
  40                 /*
  41                  * On Windows, EPIPE is returned only by the first write()
  42                  * after the reading end has closed its handle; subsequent
  43                  * write()s return EINVAL.
  44                  */
  45                 if (errno == EPIPE || errno == EINVAL)
  46 #endif
  47                         exit(0);
  48                 die("write failure on %s: %s", desc, strerror(errno));
  49         }
  50 }
  51
  52 int read_in_full(int fd, void *buf, size_t count)
  53 {
  54         char *p = buf;
  55         ssize_t total = 0;
  56
  57         while (count > 0) {
  58                 ssize_t loaded = xread(fd, p, count);
  59                 if (loaded <= 0)
  60                         return total ? total : loaded;
  61                 count -= loaded;
  62                 p += loaded;
  63                 total += loaded;
  64         }
  65
  66         return total;
  67 }
  68
  69 int write_in_full(int fd, const void *buf, size_t count)
  70 {
  71         const char *p = buf;
  72         ssize_t total = 0;
  73
  74         while (count > 0) {
  75                 ssize_t written = xwrite(fd, p, count);
  76                 if (written < 0)
  77                         return -1;
  78                 if (!written) {
  79                         errno = ENOSPC;
  80                         return -1;
  81                 }
  82                 count -= written;
  83                 p += written;
  84                 total += written;
  85         }
  86
  87         return total;
  88 }
  89
  90 void write_or_die(int fd, const void *buf, size_t count)
  91 {
  92         if (write_in_full(fd, buf, count) < 0) {
  93                 if (errno == EPIPE)
  94                         exit(0);
  95                 die("write error (%s)", strerror(errno));
  96         }
  97 }
  98
  99 int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg)
 100 {
 101         if (write_in_full(fd, buf, count) < 0) {
 102                 if (errno == EPIPE)
 103                         exit(0);
 104                 fprintf(stderr, "%s: write error (%s)\n",
 105                         msg, strerror(errno));
 106                 return 0;
 107         }
 108
 109         return 1;
 110 }
 111
 112 int write_or_whine(int fd, const void *buf, size_t count, const char *msg)
 113 {
 114         if (write_in_full(fd, buf, count) < 0) {
 115                 fprintf(stderr, "%s: write error (%s)\n",
 116                         msg, strerror(errno));
 117                 return 0;
 118         }
 119
 120         return 1;
 121 }