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 #include <unistd.h>
  10
  11 #include "util/compress.h"
  12 #include "util/util.h"
  13 #include "util/debug.h"
  14
  15
  16 #define CHUNK_SIZE  16384
  17
  18 int gzip_decompress_to_file(const char *input, int output_fd)
  19 {
  20         int ret = Z_STREAM_ERROR;
  21         int input_fd;
  22         void *ptr;
  23         int len;
  24         struct stat stbuf;
  25         unsigned char buf[CHUNK_SIZE];
  26         z_stream zs = {
  27                 .zalloc         = Z_NULL,
  28                 .zfree          = Z_NULL,
  29                 .opaque         = Z_NULL,
  30                 .avail_in       = 0,
  31                 .next_in        = Z_NULL,
  32         };
  33
  34         input_fd = open(input, O_RDONLY);
  35         if (input_fd < 0)
  36                 return -1;
  37
  38         if (fstat(input_fd, &stbuf) < 0)
  39                 goto out_close;
  40
  41         ptr = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, input_fd, 0);
  42         if (ptr == MAP_FAILED)
  43                 goto out_close;
  44
  45         if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK)
  46                 goto out_unmap;
  47
  48         zs.next_in = ptr;
  49         zs.avail_in = stbuf.st_size;
  50
  51         do {
  52                 zs.next_out = buf;
  53                 zs.avail_out = CHUNK_SIZE;
  54
  55                 ret = inflate(&zs, Z_NO_FLUSH);
  56                 switch (ret) {
  57                 case Z_NEED_DICT:
  58                         ret = Z_DATA_ERROR;
  59                         /* fall through */
  60                 case Z_DATA_ERROR:
  61                 case Z_MEM_ERROR:
  62                         goto out;
  63                 default:
  64                         break;
  65                 }
  66
  67                 len = CHUNK_SIZE - zs.avail_out;
  68                 if (writen(output_fd, buf, len) != len) {
  69                         ret = Z_DATA_ERROR;
  70                         goto out;
  71                 }
  72
  73         } while (ret != Z_STREAM_END);
  74
  75 out:
  76         inflateEnd(&zs);
  77 out_unmap:
  78         munmap(ptr, stbuf.st_size);
  79 out_close:
  80         close(input_fd);
  81
  82         return ret == Z_STREAM_END ? 0 : -1;
  83 }
  84
  85 bool gzip_is_compressed(const char *input)
  86 {
  87         int fd = open(input, O_RDONLY);
  88         const uint8_t magic[2] = { 0x1f, 0x8b };
  89         char buf[2] = { 0 };
  90         ssize_t rc;
  91
  92         if (fd < 0)
  93                 return -1;
  94
  95         rc = read(fd, buf, sizeof(buf));
  96         close(fd);
  97         return rc == sizeof(buf) ?
  98                memcmp(buf, magic, sizeof(buf)) == 0 : false;
  99 }