gcc/testsuite/c-c++-common/analyzer/feasibility-3.c

   1 /* Reduced and adapted from Linux: fs/proc/inode.c: proc_reg_open
   2    (GPL v2.0).  */
   3
   4 /* { dg-additional-options "-Wno-analyzer-too-complex -Wno-analyzer-symbol-too-complex" } */
   5
   6 /* Types.  */
   7
   8 typedef unsigned char u8;
   9 #ifndef __cplusplus
  10 typedef _Bool bool;
  11 #endif
  12 typedef unsigned int gfp_t;
  13
  14 struct file;
  15 struct kmem_cache;
  16 struct proc_dir_entry;
  17
  18 struct inode { /* [...snip...] */ };
  19
  20 enum {
  21  PROC_ENTRY_PERMANENT = 1U << 0,
  22 };
  23
  24 struct proc_ops {
  25  /* [...snip...] */
  26  int (*proc_open)(struct inode *, struct file *);
  27  /* [...snip...] */
  28  int (*proc_release)(struct inode *, struct file *);
  29  /* [...snip...] */
  30 };
  31
  32 struct proc_dir_entry {
  33  /* [...snip...] */
  34  struct completion *pde_unload_completion;
  35  /* [...snip...] */
  36  union {
  37   const struct proc_ops *proc_ops;
  38   const struct file_operations *proc_dir_ops;
  39  };
  40  /* [...snip...] */
  41  u8 flags;
  42  /* [...snip...] */
  43 };
  44
  45 struct pde_opener {
  46  /* [...snip...] */
  47  struct file *file;
  48  /* [...snip...] */
  49 };
  50
  51 struct proc_inode {
  52  /* [...snip...] */
  53  struct proc_dir_entry *pde;
  54  /* [...snip...] */
  55  struct inode vfs_inode;
  56 };
  57
  58 /* Data.  */
  59
  60 static struct kmem_cache *pde_opener_cache __attribute__((__section__(".data..ro_after_init")));
  61
  62 /* Functions. */
  63
  64 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __attribute__((__malloc__));
  65 void kmem_cache_free(struct kmem_cache *, void *);
  66
  67 static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
  68 {
  69  return pde->flags & PROC_ENTRY_PERMANENT;
  70 }
  71
  72 static inline struct proc_inode *PROC_I(const struct inode *inode)
  73 {
  74   char *__mptr = (char *)(inode);
  75   return ((struct proc_inode *)(__mptr - __builtin_offsetof(struct proc_inode, vfs_inode)));
  76 }
  77
  78 static inline struct proc_dir_entry *PDE(const struct inode *inode)
  79 {
  80  return PROC_I(inode)->pde;
  81 }
  82
  83 /* We don't want to emit bogus use of uninitialized value 'pdeo'
  84    warnings from -Wanalyzer-use-of-uninitialized-value in this function;
  85    these would require following infeasible paths in which "release" is
  86    first NULL (to avoid the initialization of "pdeo") and then is non-NULL
  87    (to access "pdeo").
  88
  89    "release" is sufficiently complicated in this function to hit the
  90    complexity limit for symbolic values during enode exploration.  */
  91
  92 static int proc_reg_open(struct inode *inode, struct file *file)
  93 {
  94  struct proc_dir_entry *pde = PDE(inode);
  95  int rv = 0;
  96
  97
  98  int (*open)(struct inode *, struct file *);
  99  int (*release)(struct inode *, struct file *);
 100
 101  struct pde_opener *pdeo;
 102
 103  if (pde_is_permanent(pde)) {
 104   open = pde->proc_ops->proc_open;
 105   if (open)
 106    rv = open(inode, file);
 107   return rv;
 108  }
 109
 110  /* [...snip...] */
 111
 112  release = pde->proc_ops->proc_release;
 113  if (release) {
 114   pdeo = (struct pde_opener *) kmem_cache_alloc(pde_opener_cache,
 115                           ((( gfp_t)(0x400u|0x800u))
 116                            | (( gfp_t)0x40u)
 117                            | (( gfp_t)0x80u)));
 118   if (!pdeo) {
 119    rv = -12;
 120    goto out_unuse;
 121   }
 122  }
 123
 124  open = pde->proc_ops->proc_open;
 125  if (open)
 126   rv = open(inode, file);
 127
 128  if (release) {
 129   if (rv == 0) {
 130
 131    pdeo->file = file; /* { dg-bogus "uninit" } */
 132    /* [...snip...] */
 133   } else
 134    kmem_cache_free(pde_opener_cache, pdeo); /* { dg-bogus "uninit" } */
 135  }
 136
 137 out_unuse:
 138  /* [...snip...] */
 139  return rv;
 140 }