tools/perf/util/zlib.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <sys/stat.h>
   6 #include <sys/mman.h>
   7 #include <zlib.h>
   8 #include <linux/compiler.h>
   9
  10 #include "util/compress.h"
  11 #include "util/util.h"
  12 #include "util/debug.h"
  13
  14
  15 #define CHUNK_SIZE  16384
  16
  17 int gzip_decompress_to_file(const char *input, int output_fd)
  18 {
  19         int ret = Z_STREAM_ERROR;
  20         int input_fd;
  21         void *ptr;
  22         int len;
  23         struct stat stbuf;
  24         unsigned char buf[CHUNK_SIZE];
  25         z_stream zs = {
  26                 .zalloc         = Z_NULL,
  27                 .zfree          = Z_NULL,
  28                 .opaque         = Z_NULL,
  29                 .avail_in       = 0,
  30                 .next_in        = Z_NULL,
  31         };
  32
  33         input_fd = open(input, O_RDONLY);
  34         if (input_fd < 0)
  35                 return -1;
  36
  37         if (fstat(input_fd, &stbuf) < 0)
  38                 goto out_close;
  39
  40         ptr = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, input_fd, 0);
  41         if (ptr == MAP_FAILED)
  42                 goto out_close;
  43
  44         if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK)
  45                 goto out_unmap;
  46
  47         zs.next_in = ptr;
  48         zs.avail_in = stbuf.st_size;
  49
  50         do {
  51                 zs.next_out = buf;
  52                 zs.avail_out = CHUNK_SIZE;
  53
  54                 ret = inflate(&zs, Z_NO_FLUSH);
  55                 switch (ret) {
  56                 case Z_NEED_DICT:
  57                         ret = Z_DATA_ERROR;
  58                         /* fall through */
  59                 case Z_DATA_ERROR:
  60                 case Z_MEM_ERROR:
  61                         goto out;
  62                 default:
  63                         break;
  64                 }
  65
  66                 len = CHUNK_SIZE - zs.avail_out;
  67                 if (writen(output_fd, buf, len) != len) {
  68                         ret = Z_DATA_ERROR;
  69                         goto out;
  70                 }
  71
  72         } while (ret != Z_STREAM_END);
  73
  74 out:
  75         inflateEnd(&zs);
  76 out_unmap:
  77         munmap(ptr, stbuf.st_size);
  78 out_close:
  79         close(input_fd);
  80
  81         return ret == Z_STREAM_END ? 0 : -1;
  82 }
  83
  84 bool gzip_is_compressed(const char *input)
  85 {
  86         int fd = open(input, O_RDONLY);
  87         const uint8_t magic[2] = { 0x1f, 0x8b };
  88         char buf[2] = { 0 };
  89         ssize_t rc;
  90
  91         if (fd < 0)
  92                 return -1;
  93
  94         rc = read(fd, buf, sizeof(buf));
  95         close(fd);
  96         return rc == sizeof(buf) ?
  97                memcmp(buf, magic, sizeof(buf)) == 0 : false;
  98 }