security_utilities/fileIo.c

   1 /*
   2  * Copyright (c) 2005-2007,2010 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
  23     if (!fileName) {
  24         fwrite(bytes, 1, numBytes, stdout);
  25         fflush(stdout);
  26         return ferror(stdout);
  27     }
  28
  29         fd = open(fileName, O_RDWR | O_CREAT | O_TRUNC, 0600);
  30         if(fd <= 0) {
  31                 return errno;
  32         }
  33         rtn = write(fd, bytes, (size_t)numBytes);
  34         if(rtn != (int)numBytes) {
  35                 if(rtn >= 0) {
  36                         fprintf(stderr, "writeFile: short write\n");
  37                 }
  38                 rtn = EIO;
  39         }
  40         else {
  41                 rtn = 0;
  42         }
  43         close(fd);
  44         return rtn;
  45 }
  46
  47 /*
  48  * Read entire file.
  49  */
  50 int readFile(
  51         const char              *fileName,
  52         unsigned char   **bytes,                // mallocd and returned
  53         size_t          *numBytes)              // returned
  54 {
  55         int rtn;
  56         int fd;
  57         char *buf;
  58         struct stat     sb;
  59         size_t size;
  60
  61         *numBytes = 0;
  62         *bytes = NULL;
  63         fd = open(fileName, O_RDONLY);
  64         if(fd <= 0) {
  65                 return errno;
  66         }
  67         rtn = fstat(fd, &sb);
  68         if(rtn) {
  69                 goto errOut;
  70         }
  71         if (sb.st_size > SIZE_MAX) {
  72                 rtn = EFBIG;
  73                 goto errOut;
  74         }
  75         size = (size_t)sb.st_size;
  76         buf = (char *)malloc(size);
  77         if(buf == NULL) {
  78                 rtn = ENOMEM;
  79                 goto errOut;
  80         }
  81         rtn = read(fd, buf, (size_t)size);
  82         if(rtn != (int)size) {
  83                 if(rtn >= 0) {
  84                         fprintf(stderr, "readFile: short read\n");
  85                 }
  86                 rtn = EIO;
  87         }
  88         else {
  89                 rtn = 0;
  90                 *bytes = (unsigned char *)buf;
  91                 *numBytes = size;
  92         }
  93
  94 errOut:
  95         close(fd);
  96         return rtn;
  97 }