OSX/utilities/src/fileIo.c

   1 /*
   2  * Copyright (c) 2005-2007,2010,2012-2013 Apple Inc. All Rights Reserved.
   3  */
   4
   5 #include <unistd.h>
   6 #include <fcntl.h>
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <stdint.h>
  13 #include "fileIo.h"
  14
  15 int writeFile(
  16         const char                      *fileName,
  17         const unsigned char     *bytes,
  18         size_t              numBytes)
  19 {
  20         int             rtn;
  21         int     fd;
  22     ssize_t wrc;
  23
  24     if (!fileName) {
  25         fwrite(bytes, 1, numBytes, stdout);
  26         fflush(stdout);
  27         return ferror(stdout);
  28     }
  29
  30         fd = open(fileName, O_RDWR | O_CREAT | O_TRUNC, 0600);
  31         if(fd <= 0) {
  32                 return errno;
  33         }
  34         wrc = write(fd, bytes, (size_t)numBytes);
  35         if(wrc != numBytes) {
  36                 if(wrc >= 0) {
  37                         fprintf(stderr, "writeFile: short write\n");
  38                 }
  39                 rtn = EIO;
  40         }
  41         else {
  42                 rtn = 0;
  43         }
  44         close(fd);
  45         return rtn;
  46 }
  47
  48 /*
  49  * Read entire file.
  50  */
  51 int readFile(
  52         const char              *fileName,
  53         unsigned char   **bytes,                // mallocd and returned
  54         size_t          *numBytes)              // returned
  55 {
  56         int rtn;
  57         int fd;
  58         char *buf;
  59         struct stat     sb;
  60         size_t size;
  61     ssize_t rrc;
  62
  63         *numBytes = 0;
  64         *bytes = NULL;
  65         fd = open(fileName, O_RDONLY);
  66         if(fd <= 0) {
  67                 return errno;
  68         }
  69         rtn = fstat(fd, &sb);
  70         if(rtn) {
  71                 goto errOut;
  72         }
  73         if (sb.st_size > SIZE_MAX) {
  74                 rtn = EFBIG;
  75                 goto errOut;
  76         }
  77         size = (size_t)sb.st_size;
  78         buf = (char *)malloc(size);
  79         if(buf == NULL) {
  80                 rtn = ENOMEM;
  81                 goto errOut;
  82         }
  83         rrc = read(fd, buf, size);
  84         if(rrc != size) {
  85                 if(rtn >= 0) {
  86             free(buf);
  87                         fprintf(stderr, "readFile: short read\n");
  88                 }
  89                 rtn = EIO;
  90         }
  91         else {
  92                 rtn = 0;
  93                 *bytes = (unsigned char *)buf;
  94                 *numBytes = size;
  95         }
  96
  97 errOut:
  98         close(fd);
  99         return rtn;
 100 }