zlibsupport.c

   1 /* Support for compressed modules.  Willy Tarreau <willy@meta-x.org>
   2  * did the support for modutils, Andrey Borzenkov <arvidjaar@mail.ru>
   3  * ported it to module-init-tools, and I said it was too ugly to live
   4  * and rewrote it 8).
   5  *
   6  * (C) 2003 Rusty Russell, IBM Corporation.
   7  */
   8 #include <sys/types.h>
   9 #include <sys/stat.h>
  10 #include <fcntl.h>
  11 #include <errno.h>
  12 #include <stdlib.h>
  13 #include <unistd.h>
  14 #include <sys/mman.h>
  15
  16 #include "zlibsupport.h"
  17 #include "logging.h"
  18 #include "testing.h"
  19
  20 #ifdef CONFIG_USE_ZLIB
  21 #include <zlib.h>
  22
  23 void *grab_contents(gzFile *gzfd, unsigned long *size)
  24 {
  25         unsigned int max = 16384;
  26         void *buffer = NOFAIL(malloc(max));
  27         int ret;
  28
  29         *size = 0;
  30         while ((ret = gzread(gzfd, buffer + *size, max - *size)) > 0) {
  31                 *size += ret;
  32                 if (*size == max)
  33                         buffer = NOFAIL(realloc(buffer, max *= 2));
  34         }
  35         if (ret < 0) {
  36                 free(buffer);
  37                 buffer = NULL;
  38         }
  39
  40         return buffer;
  41 }
  42
  43 /* gzopen handles uncompressed files transparently. */
  44 void *grab_file(const char *filename, unsigned long *size)
  45 {
  46         gzFile gzfd;
  47         void *buffer;
  48
  49         errno = 0;
  50         gzfd = gzopen(filename, "rb");
  51         if (!gzfd) {
  52                 if (errno == ENOMEM)
  53                         fatal("Memory allocation failure in gzopen\n");
  54                 return NULL;
  55         }
  56         buffer = grab_contents(gzfd, size);
  57         gzclose(gzfd);
  58         return buffer;
  59 }
  60
  61 void release_file(void *data, unsigned long size)
  62 {
  63         free(data);
  64 }
  65 #else /* ... !CONFIG_USE_ZLIB */
  66
  67 void *grab_fd(int fd, unsigned long *size)
  68 {
  69         struct stat st;
  70         void *map;
  71         int ret;
  72
  73         ret = fstat(fd, &st);
  74         if (ret < 0)
  75                 return NULL;
  76         *size = st.st_size;
  77         map = mmap(0, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
  78         if (map == MAP_FAILED)
  79                 map = NULL;
  80         return map;
  81 }
  82
  83 void *grab_file(const char *filename, unsigned long *size)
  84 {
  85         int fd;
  86         void *map;
  87
  88         fd = open(filename, O_RDONLY, 0);
  89         if (fd < 0)
  90                 return NULL;
  91         map = grab_fd(fd, size);
  92         close(fd);
  93         return map;
  94 }
  95
  96 void release_file(void *data, unsigned long size)
  97 {
  98         munmap(data, size);
  99 }
 100 #endif