contrib/libjeffpc/io.c

   1 /*
   2  * Copyright (c) 2011-2016 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy
   5  * of this software and associated documentation files (the "Software"), to deal
   6  * in the Software without restriction, including without limitation the rights
   7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8  * copies of the Software, and to permit persons to whom the Software is
   9  * furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  20  * SOFTWARE.
  21  */
  22
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdlib.h>
  26 #include <stdbool.h>
  27 #include <stdio.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <fcntl.h>
  31 #include <string.h>
  32 #include <sys/uio.h>
  33
  34 #include <jeffpc/io.h>
  35 #include <jeffpc/error.h>
  36
  37 static inline ssize_t rw(int fd, void *buf, size_t nbyte, off_t off,
  38                          const bool useoff, const bool readfxns)
  39 {
  40         char *ptr = buf;
  41         size_t total;
  42         ssize_t ret;
  43
  44         total = 0;
  45
  46         while (nbyte) {
  47                 if (readfxns) {
  48                         if (useoff)
  49                                 ret = pread(fd, ptr, nbyte, off);
  50                         else
  51                                 ret = read(fd, ptr, nbyte);
  52                 } else {
  53                         if (useoff)
  54                                 ret = pwrite(fd, ptr, nbyte, off);
  55                         else
  56                                 ret = write(fd, ptr, nbyte);
  57                 }
  58
  59                 if (ret < 0)
  60                         return -errno;
  61
  62                 if (ret == 0)
  63                         return -EPIPE;
  64
  65                 nbyte -= ret;
  66                 total += ret;
  67                 ptr   += ret;
  68                 off   += ret;
  69         }
  70
  71         return 0;
  72 }
  73
  74 int xread(int fd, void *buf, size_t nbyte)
  75 {
  76         return rw(fd, buf, nbyte, 0, false, true);
  77 }
  78
  79 int xpread(int fd, void *buf, size_t nbyte, off_t off)
  80 {
  81         return rw(fd, buf, nbyte, off, true, true);
  82 }
  83
  84 int xwrite(int fd, const void *buf, size_t nbyte)
  85 {
  86         return rw(fd, (void *) buf, nbyte, 0, false, false);
  87 }
  88
  89 int xpwrite(int fd, const void *buf, size_t nbyte, off_t off)
  90 {
  91         return rw(fd, (void *) buf, nbyte, off, true, false);
  92 }
  93
  94 char *read_file_common(int dirfd, const char *fname, struct stat *sb)
  95 {
  96         struct stat statbuf;
  97         char *out;
  98         int ret;
  99         int fd;
 100
 101         fd = xopenat(dirfd, fname, O_RDONLY, 0);
 102         if (fd < 0) {
 103                 out = ERR_PTR(fd);
 104                 goto err;
 105         }
 106
 107         ret = fstat(fd, &statbuf);
 108         if (ret == -1) {
 109                 out = ERR_PTR(-errno);
 110                 goto err_close;
 111         }
 112
 113         out = malloc(statbuf.st_size + 1);
 114         if (!out) {
 115                 out = ERR_PTR(-ENOMEM);
 116                 goto err_close;
 117         }
 118
 119         ret = xread(fd, out, statbuf.st_size);
 120         if (ret) {
 121                 free(out);
 122                 out = ERR_PTR(ret);
 123         } else {
 124                 out[statbuf.st_size] = '\0';
 125
 126                 if (sb)
 127                         *sb = statbuf;
 128         }
 129
 130 err_close:
 131         xclose(fd);
 132
 133 err:
 134         return out;
 135 }
 136
 137 int write_file(const char *fname, const char *data, size_t len)
 138 {
 139         int ret;
 140         int fd;
 141
 142         fd = xopen(fname, O_WRONLY | O_CREAT | O_EXCL,
 143                    S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 144         if (fd < 0)
 145                 return fd;
 146
 147         ret = xwrite(fd, data, len);
 148
 149         xclose(fd);
 150
 151         return ret;
 152 }