kernel/tools/perf/util/zlib.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 #include <sys/stat.h>
   4 #include <sys/mman.h>
   5 #include <zlib.h>
   6
   7 #include "util/util.h"
   8 #include "util/debug.h"
   9
  10
  11 #define CHUNK_SIZE  16384
  12
  13 int gzip_decompress_to_file(const char *input, int output_fd)
  14 {
  15         int ret = Z_STREAM_ERROR;
  16         int input_fd;
  17         void *ptr;
  18         int len;
  19         struct stat stbuf;
  20         unsigned char buf[CHUNK_SIZE];
  21         z_stream zs = {
  22                 .zalloc         = Z_NULL,
  23                 .zfree          = Z_NULL,
  24                 .opaque         = Z_NULL,
  25                 .avail_in       = 0,
  26                 .next_in        = Z_NULL,
  27         };
  28
  29         input_fd = open(input, O_RDONLY);
  30         if (input_fd < 0)
  31                 return -1;
  32
  33         if (fstat(input_fd, &stbuf) < 0)
  34                 goto out_close;
  35
  36         ptr = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, input_fd, 0);
  37         if (ptr == MAP_FAILED)
  38                 goto out_close;
  39
  40         if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK)
  41                 goto out_unmap;
  42
  43         zs.next_in = ptr;
  44         zs.avail_in = stbuf.st_size;
  45
  46         do {
  47                 zs.next_out = buf;
  48                 zs.avail_out = CHUNK_SIZE;
  49
  50                 ret = inflate(&zs, Z_NO_FLUSH);
  51                 switch (ret) {
  52                 case Z_NEED_DICT:
  53                         ret = Z_DATA_ERROR;
  54                         /* fall through */
  55                 case Z_DATA_ERROR:
  56                 case Z_MEM_ERROR:
  57                         goto out;
  58                 default:
  59                         break;
  60                 }
  61
  62                 len = CHUNK_SIZE - zs.avail_out;
  63                 if (writen(output_fd, buf, len) != len) {
  64                         ret = Z_DATA_ERROR;
  65                         goto out;
  66                 }
  67
  68         } while (ret != Z_STREAM_END);
  69
  70 out:
  71         inflateEnd(&zs);
  72 out_unmap:
  73         munmap(ptr, stbuf.st_size);
  74 out_close:
  75         close(input_fd);
  76
  77         return ret == Z_STREAM_END ? 0 : -1;
  78 }