gcc/testsuite/c-c++-common/analyzer/deref-before-check-pr108455-git-pack-revindex.c

   1 /* Reduced from git-2.39.0's pack-revindex.c  */
   2
   3 typedef unsigned int __uint32_t;
   4 typedef unsigned long int __uintmax_t;
   5 typedef long int __off_t;
   6 typedef long int __off64_t;
   7 typedef __SIZE_TYPE__ size_t;
   8 typedef __off64_t off_t;
   9 typedef __uint32_t uint32_t;
  10 typedef __uintmax_t uintmax_t;
  11
  12 struct stat {
  13   /* [...snip...] */
  14   __off_t st_size;
  15   /* [...snip...] */
  16 };
  17
  18 extern int close(int __fd);
  19 extern int fstat(int __fd, struct stat *__buf)
  20   __attribute__((__nothrow__, __leaf__)) __attribute__((__nonnull__(2)));
  21 extern uint32_t default_swab32(uint32_t val);
  22 extern uint32_t git_bswap32(uint32_t x);
  23 __attribute__((__noreturn__)) void die(const char *err, ...)
  24     __attribute__((format(printf, 1, 2)));
  25 int error(const char *err, ...) __attribute__((format(printf, 1, 2)));
  26 int error_errno(const char *err, ...) __attribute__((format(printf, 1, 2)));
  27 static inline int const_error(void) { return -1; }
  28 extern int munmap(void *__addr, size_t __len)
  29     __attribute__((__nothrow__, __leaf__));
  30 extern size_t st_mult(size_t a, size_t b);
  31 extern void *xmmap(void *start, size_t length, int prot, int flags, int fd,
  32                    off_t offset);
  33 extern size_t xsize_t(off_t len);
  34
  35 extern char *gettext(const char *__msgid) __attribute__((__nothrow__, __leaf__))
  36 __attribute__((__format_arg__(1)));
  37 static inline __attribute__((format_arg(1))) const char *_(const char *msgid) {
  38   if (!*msgid)
  39     return "";
  40   return gettext(msgid);
  41 }
  42
  43 struct repository {
  44   /* [...snip...] */
  45   const struct git_hash_algo *hash_algo;
  46   /* [...snip...] */
  47 };
  48 extern struct repository *the_repository;
  49 struct git_hash_algo {
  50   /* [...snip...] */
  51   size_t rawsz;
  52   /* [...snip...] */
  53 };
  54
  55 int git_open_cloexec(const char *name, int flags);
  56
  57 struct revindex_header {
  58   uint32_t signature;
  59   uint32_t version;
  60   uint32_t hash_id;
  61 };
  62
  63 int load_revindex_from_disk(char *revindex_name, uint32_t num_objects,
  64                             const uint32_t **data_p, size_t *len_p) {
  65   int fd, ret = 0;
  66   struct stat st;
  67   void *data = ((void *)0);
  68   size_t revindex_size;
  69   struct revindex_header *hdr;
  70
  71   fd = git_open_cloexec(revindex_name, 00);
  72
  73   if (fd < 0) {
  74     ret = -1;
  75     goto cleanup;
  76   }
  77   if (fstat(fd, &st)) {
  78     ret = (error_errno(_("failed to read %s"), revindex_name), const_error());
  79     goto cleanup;
  80   }
  81
  82   revindex_size = xsize_t(st.st_size);
  83
  84   if (revindex_size < ((12) + (2 * the_repository->hash_algo->rawsz))) {
  85     ret = (error(_("reverse-index file %s is too small"), revindex_name),
  86            const_error());
  87     goto cleanup;
  88   }
  89
  90   if (revindex_size - ((12) + (2 * the_repository->hash_algo->rawsz)) !=
  91       st_mult(sizeof(uint32_t), num_objects)) {
  92     ret = (error(_("reverse-index file %s is corrupt"), revindex_name),
  93            const_error());
  94     goto cleanup;
  95   }
  96
  97   data = xmmap(((void *)0), revindex_size, 0x1, 0x02, fd, 0);
  98   hdr = (struct revindex_header *) data;
  99
 100   if (git_bswap32(hdr->signature) != 0x52494458) {
 101     ret =
 102         (error(_("reverse-index file %s has unknown signature"), revindex_name),
 103          const_error());
 104     goto cleanup;
 105   }
 106   if (git_bswap32(hdr->version) != 1) {
 107     ret = (error(_("reverse-index file %s has unsupported version %"
 108                    "u"),
 109                  revindex_name, git_bswap32(hdr->version)),
 110            const_error());
 111     goto cleanup;
 112   }
 113   if (!(git_bswap32(hdr->hash_id) == 1 || git_bswap32(hdr->hash_id) == 2)) {
 114     ret = (error(_("reverse-index file %s has unsupported hash id %"
 115                    "u"),
 116                  revindex_name, git_bswap32(hdr->hash_id)),
 117            const_error());
 118     goto cleanup;
 119   }
 120
 121 cleanup:
 122   if (ret) {
 123     if (data) /* { dg-bogus "check of 'data' for NULL after already dereferencing it" } */
 124       munmap(data, revindex_size);
 125   } else {
 126     *len_p = revindex_size;
 127     *data_p = (const uint32_t *)data;
 128   }
 129
 130   if (fd >= 0)
 131     close(fd);
 132   return ret;
 133 }