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                 if (errno == EPIPE)
  38                         exit(0);
  39                 die("write failure on %s: %s", desc, strerror(errno));
  40         }
  41 }
  42
  43 ssize_t read_in_full(int fd, void *buf, size_t count)
  44 {
  45         char *p = buf;
  46         ssize_t total = 0;
  47
  48         while (count > 0) {
  49                 ssize_t loaded = xread(fd, p, count);
  50                 if (loaded <= 0)
  51                         return total ? total : loaded;
  52                 count -= loaded;
  53                 p += loaded;
  54                 total += loaded;
  55         }
  56
  57         return total;
  58 }
  59
  60 ssize_t write_in_full(int fd, const void *buf, size_t count)
  61 {
  62         const char *p = buf;
  63         ssize_t total = 0;
  64
  65         while (count > 0) {
  66                 ssize_t written = xwrite(fd, p, count);
  67                 if (written < 0)
  68                         return -1;
  69                 if (!written) {
  70                         errno = ENOSPC;
  71                         return -1;
  72                 }
  73                 count -= written;
  74                 p += written;
  75                 total += written;
  76         }
  77
  78         return total;
  79 }
  80
  81 void fsync_or_die(int fd, const char *msg)
  82 {
  83         if (fsync(fd) < 0) {
  84                 die("%s: fsync error (%s)", msg, strerror(errno));
  85         }
  86 }
  87
  88 void write_or_die(int fd, const void *buf, size_t count)
  89 {
  90         if (write_in_full(fd, buf, count) < 0) {
  91                 if (errno == EPIPE)
  92                         exit(0);
  93                 die("write error (%s)", strerror(errno));
  94         }
  95 }
  96
  97 int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg)
  98 {
  99         if (write_in_full(fd, buf, count) < 0) {
 100                 if (errno == EPIPE)
 101                         exit(0);
 102                 fprintf(stderr, "%s: write error (%s)\n",
 103                         msg, strerror(errno));
 104                 return 0;
 105         }
 106
 107         return 1;
 108 }
 109
 110 int write_or_whine(int fd, const void *buf, size_t count, const char *msg)
 111 {
 112         if (write_in_full(fd, buf, count) < 0) {
 113                 fprintf(stderr, "%s: write error (%s)\n",
 114                         msg, strerror(errno));
 115                 return 0;
 116         }
 117
 118         return 1;
 119 }