diff mbox series

[5/8] posix: Use dynarray for globname in glob

Message ID 20210105185820.3796657-6-adhemerval.zanella@linaro.org
State New
Delegated to: Arjun Shankar
Headers show
Series Remove alloca usage from glob | expand

Commit Message

Adhemerval Zanella Jan. 5, 2021, 6:58 p.m. UTC
This patch uses dynarray at glob internal glob_in_dir function to manage
the various matched patterns.  It simplify and removes all the boilerplate
buffer managements required.  It also removes the glob_use_alloca, since
it is not used anymore.

Checked on x86_64-linux-gnu.
---
 posix/glob.c | 126 +++++++++++++++------------------------------------
 1 file changed, 37 insertions(+), 89 deletions(-)
diff mbox series

Patch

diff --git a/posix/glob.c b/posix/glob.c
index d734ca977c..d199204931 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -1203,6 +1203,21 @@  prefix_array (const char *dirname, char **array, size_t n)
   return 0;
 }
 
+struct globnames_result
+{
+  char **names;
+  size_t length;
+};
+
+/* Create a dynamic array for C string representing the glob name found.  */
+#define DYNARRAY_STRUCT            globnames_array
+#define DYNARRAY_ELEMENT_FREE(ptr) free (*ptr)
+#define DYNARRAY_ELEMENT           char *
+#define DYNARRAY_PREFIX            globnames_array_
+#define DYNARRAY_FINAL_TYPE        struct globnames_result
+#define DYNARRAY_INITIAL_SIZE      64
+#include <malloc/dynarray-skeleton.c>
+
 /* Like 'glob', but PATTERN is a final pathname component,
    and matches are searched for in DIRECTORY.
    The GLOB_NOSORT bit in FLAGS is ignored.  No sorting is ever done.
@@ -1213,25 +1228,13 @@  glob_in_dir (const char *pattern, const char *directory, int flags,
              glob_t *pglob, size_t alloca_used)
 {
   void *stream = NULL;
-# define GLOBNAMES_MEMBERS(nnames) \
-    struct globnames *next; size_t count; char *name[nnames];
-  struct globnames { GLOBNAMES_MEMBERS (FLEXIBLE_ARRAY_MEMBER) };
-  struct { GLOBNAMES_MEMBERS (64) } init_names_buf;
-  struct globnames *init_names = (struct globnames *) &init_names_buf;
-  struct globnames *names = init_names;
-  struct globnames *names_alloca = init_names;
+  struct globnames_array globnames;
   size_t nfound = 0;
-  size_t cur = 0;
   int meta;
   int save;
   int result;
 
-  alloca_used += sizeof init_names_buf;
-
-  init_names->next = NULL;
-  init_names->count = ((sizeof init_names_buf
-                        - offsetof (struct globnames, name))
-                       / sizeof init_names->name[0]);
+  globnames_array_init (&globnames);
 
   meta = __glob_pattern_type (pattern, !(flags & GLOB_NOESCAPE));
   if (meta == GLOBPAT_NONE && (flags & (GLOB_NOCHECK|GLOB_NOMAGIC)))
@@ -1308,34 +1311,10 @@  glob_in_dir (const char *pattern, const char *directory, int flags,
 
               if (fnmatch (pattern, d.name, fnm_flags) == 0)
                 {
-                  if (cur == names->count)
-                    {
-                      struct globnames *newnames;
-                      size_t count = names->count * 2;
-                      size_t nameoff = offsetof (struct globnames, name);
-                      size_t size = FLEXSIZEOF (struct globnames, name,
-                                                count * sizeof (char *));
-                      if ((SIZE_MAX - nameoff) / 2 / sizeof (char *)
-                          < names->count)
-                        goto memory_error;
-                      if (glob_use_alloca (alloca_used, size))
-                        newnames = names_alloca
-                          = alloca_account (size, alloca_used);
-                      else if ((newnames = malloc (size))
-                               == NULL)
-                        goto memory_error;
-                      newnames->count = count;
-                      newnames->next = names;
-                      names = newnames;
-                      cur = 0;
-                    }
-                  names->name[cur] = strdup (d.name);
-                  if (names->name[cur] == NULL)
-                    goto memory_error;
-                  ++cur;
-                  ++nfound;
-                  if (SIZE_MAX - pglob->gl_offs <= nfound)
+                  globnames_array_add (&globnames, strdup (d.name));
+                  if (globnames_array_has_failed (&globnames))
                     goto memory_error;
+                  nfound++;
                 }
             }
         }
@@ -1345,10 +1324,13 @@  glob_in_dir (const char *pattern, const char *directory, int flags,
     {
       size_t len = strlen (pattern);
       nfound = 1;
-      names->name[cur] = malloc (len + 1);
-      if (names->name[cur] == NULL)
+      char *newp = malloc (len + 1);
+      if (newp == NULL)
         goto memory_error;
-      *((char *) mempcpy (names->name[cur++], pattern, len)) = '\0';
+      *((char *) mempcpy (newp, pattern, len)) = '\0';
+      globnames_array_add (&globnames, newp);
+      if (globnames_array_has_failed (&globnames))
+       goto memory_error;
     }
 
   result = GLOB_NOMATCH;
@@ -1369,59 +1351,25 @@  glob_in_dir (const char *pattern, const char *directory, int flags,
       if (new_gl_pathv == NULL)
         {
         memory_error:
-          while (1)
-            {
-              struct globnames *old = names;
-              for (size_t i = 0; i < cur; ++i)
-                free (names->name[i]);
-              names = names->next;
-              /* NB: we will not leak memory here if we exit without
-                 freeing the current block assigned to OLD.  At least
-                 the very first block is always allocated on the stack
-                 and this is the block assigned to OLD here.  */
-              if (names == NULL)
-                {
-                  assert (old == init_names);
-                  break;
-                }
-              cur = names->count;
-              if (old == names_alloca)
-                names_alloca = names;
-              else
-                free (old);
-            }
+          globnames_array_free (&globnames);
           result = GLOB_NOSPACE;
         }
       else
         {
-          while (1)
+          struct globnames_result ret = { .names = 0, .length = -1 };
+          if (!globnames_array_finalize (&globnames, &ret))
+            result = GLOB_NOSPACE;
+          else
             {
-              struct globnames *old = names;
-              for (size_t i = 0; i < cur; ++i)
+              for (size_t i = 0; i < ret.length; ++i)
                 new_gl_pathv[pglob->gl_offs + pglob->gl_pathc++]
-                  = names->name[i];
-              names = names->next;
-              /* NB: we will not leak memory here if we exit without
-                 freeing the current block assigned to OLD.  At least
-                 the very first block is always allocated on the stack
-                 and this is the block assigned to OLD here.  */
-              if (names == NULL)
-                {
-                  assert (old == init_names);
-                  break;
-                }
-              cur = names->count;
-              if (old == names_alloca)
-                names_alloca = names;
-              else
-                free (old);
+                  = ret.names[i];
+              pglob->gl_pathv = new_gl_pathv;
+              pglob->gl_pathv[pglob->gl_offs + pglob->gl_pathc] = NULL;
+              pglob->gl_flags = flags;
             }
 
-          pglob->gl_pathv = new_gl_pathv;
-
-          pglob->gl_pathv[pglob->gl_offs + pglob->gl_pathc] = NULL;
-
-          pglob->gl_flags = flags;
+          free (ret.names);
         }
     }