lib/libelf/compat/mmap.c

   1 #include <sys/cdefs.h>
   2
   3 #include <sys/types.h>
   4
   5 #include <err.h>
   6 #include <errno.h>
   7 #include <libelf.h>
   8 #include <stdbool.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14 #include "_libelf.h"
  15 #include "../libelf_compat.h"
  16
  17 void *
  18 libelf_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
  19 {
  20     void *p; /* malloc'ed pointer */
  21     size_t bufsize;
  22
  23     if ((addr != NULL) || (flags != MAP_PRIVATE) || (prot != PROT_READ)) {
  24         LIBELF_SET_ERROR(ARGUMENT, 0);
  25         return (MAP_FAILED);
  26     }
  27
  28     /*
  29      * Fall back to malloc+read.
  30      */
  31     p = NULL;
  32     bufsize = 1024 * 1024;
  33     while (/*CONSTCOND*/true) {
  34         void *newp = realloc(p, bufsize);
  35         ssize_t rsz;
  36
  37         if (newp == NULL) {
  38             free(p);
  39             LIBELF_SET_ERROR(RESOURCE, 0);
  40             return (MAP_FAILED);
  41         }
  42         p = newp;
  43         rsz = pread(fd, p, bufsize, 0);
  44         if (rsz == -1) {
  45             free(p);
  46             LIBELF_SET_ERROR(IO, errno);
  47             return (MAP_FAILED);
  48         } else if ((size_t) rsz > bufsize) {
  49             free(p);
  50             LIBELF_SET_ERROR(IO, EIO); /* XXX */
  51             return (MAP_FAILED);
  52         } else if ((size_t) rsz < bufsize) {
  53             /*
  54              * try to shrink the buffer.
  55              */
  56             newp = realloc(p, (size_t) rsz);
  57             if (newp != NULL) {
  58                 p = newp;
  59             }
  60             break;
  61         }
  62         bufsize *= 2;
  63     }
  64
  65     return p;
  66 }
  67
  68 int
  69 libelf_munmap(void *addr, size_t len)
  70 {
  71     free(addr);
  72     return 0;
  73 }