mincore.c

   1 #include "compat-util.h"
   2 static int summary;
   3
   4 static int usage(const char * argv0)
   5 {
   6         fprintf(stderr,
   7                 "Usage: %s [-o OFFSET] [-l LENGTH] [-s] FILE...\n", argv0);
   8         return 1;
   9 }
  10
  11 static void mincore_stats(const char *path, off_t offset, off_t len)
  12 {
  13         char *map;
  14         unsigned char *vec;
  15         size_t vec_len;
  16         size_t map_len;
  17         off_t map_offset;
  18         int fd;
  19         size_t i;
  20         static const char *fmt = sizeof(void *) == 8 ?
  21                                  "%s: %016lx %x\n": "%s: %08lx %x\n";
  22
  23         if ((fd = open_noatime(path)) < 0) {
  24                 fprintf(stderr, "%s: open(): %s\n", path, strerror(errno));
  25                 return;
  26         }
  27
  28         if (!len) {
  29                 struct stat sb;
  30
  31                 if (fstat(fd, &sb) < 0) {
  32                         fprintf(stderr, "%s: fstat(%d): %s\n",
  33                                 path, fd, strerror(errno));
  34                         goto err_close;
  35                 }
  36                 len = sb.st_size - offset;
  37         }
  38
  39         vec_len = (len + page_size() - 1) / page_size();
  40         if (!(vec = malloc(vec_len))) {
  41                 fprintf(stderr, "%s: malloc(%lu): %s\n",
  42                         path, (unsigned long)vec_len, strerror(errno));
  43                 goto err_close;
  44         }
  45
  46         map_len = PAGE_ALIGN(len);
  47         map_offset = PAGE_ALIGN_DOWN(offset + 1);
  48
  49         map = mmap(NULL, map_len, PROT_READ, MAP_SHARED, fd, map_offset);
  50         if (map == MAP_FAILED) {
  51                 fprintf(stderr, "%s: mmap(%lu): %s\n",
  52                         path, (unsigned long)vec_len, strerror(errno));
  53                 goto err_free;
  54         }
  55
  56         if (mincore(map, map_len, vec) < 0) {
  57                 fprintf(stderr, "%s: mincore(%lu): %s\n",
  58                         path, (unsigned long)vec_len, strerror(errno));
  59                 goto err_munmap;
  60         }
  61
  62         if (summary) {
  63                 size_t n = 0;
  64
  65                 for (i = 0; i < vec_len; ++i)
  66                         if (vec[i] & 1)
  67                                 ++n;
  68                 printf("%s: %F\n", path, (double)n / (double)vec_len);
  69         } else {
  70                 for (i = 0; i < vec_len; ++i)
  71                         printf(fmt, path,
  72                                (unsigned long)((page_size() * i) + map_offset),
  73                                vec[i] & 1);
  74         }
  75 err_munmap:
  76         munmap(map, map_len);
  77 err_free:
  78         free(vec);
  79 err_close:
  80         close(fd);
  81 }
  82
  83 int main(int argc, char * const argv[])
  84 {
  85         off_t offset = 0;
  86         off_t len = 0;
  87         int argi = 1;
  88         int opt;
  89
  90         while ((opt = getopt(argc, argv, "o:l:hs")) != -1) {
  91                 char *err;
  92
  93                 ++argi;
  94                 switch(opt) {
  95                 case 'o':
  96                         ++argi;
  97                         offset = cstr_to_off_t(optarg, &err, 10);
  98                         if (*err || offset < 0) {
  99                                 fprintf(stderr, "offset must be >= 0\n");
 100                                 return 1;
 101                         }
 102                         break;
 103                 case 'l':
 104                         ++argi;
 105                         len = cstr_to_off_t(optarg, &err, 10);
 106                         if (*err || len < 0) {
 107                                 fprintf(stderr, "length must be >= 0\n");
 108                                 return 1;
 109                         }
 110                         break;
 111                 case 's':
 112                         summary = 1;
 113                         break;
 114                 default:
 115                         return usage(argv[0]);
 116                 }
 117         }
 118
 119         if (argi >= argc)
 120                 return usage(argv[0]);
 121
 122         for (; argi < argc; ++argi)
 123                 mincore_stats(argv[argi], offset, len);
 124         return 0;
 125 }