Improve pg_upgrade's load_directory() function.

Error out on out-of-memory, rather than returning -1, which the sole
existing caller wasn't checking for anyway.  There doesn't seem to be
any use-case for making the caller check for failure here.

Detect failure return from readdir().

Use a less platform-dependent method of calculating the entrysize.
It's possible, but not yet confirmed, that this explains bug #6733,
in which Mike Wilson reports a pg_upgrade crash that did not occur
in 9.1.  (Note that load_directory is effectively new code in 9.2,
at least on platforms that have scandir().)

Fix up comments, avoid uselessly using two counters, reduce the number
of realloc calls to something sane.

diff --git a/contrib/pg_upgrade/file.c b/contrib/pg_upgrade/file.c
index 1dd3722142c9e83c1ec228099c3a3fd302a2179b..962cbaccc53f9d6788b69d151a36e36fb4e3260f 100644 (file)
--- a/contrib/pg_upgrade/file.c
+++ b/contrib/pg_upgrade/file.c
@@ -224,13 +224,12 @@ copy_file(const char *srcfile, const char *dstfile, bool force)
 /*
  * load_directory()
  *
- * Returns count of files that meet the selection criteria coded in
- * the function pointed to by selector.  Creates an array of pointers
- * to dirent structures.  Address of array returned in namelist.
+ * Read all the file names in the specified directory, and return them as
+ * an array of "struct dirent" pointers.  The array address is returned in
+ * *namelist, and the function result is the count of file names.
  *
- * Note that the number of dirent structures needed is dynamically
- * allocated using realloc.  Realloc can be inefficient if invoked a
- * large number of times.
+ * To free the result data, free each namelist array member, then free the
+ * namelist array itself.
  */
 int
 load_directory(const char *dirname, struct dirent *** namelist)
@@ -238,43 +237,48 @@ load_directory(const char *dirname, struct dirent *** namelist)
        DIR                *dirdesc;
        struct dirent *direntry;
        int                     count = 0;
-       int                     name_num = 0;
+       int                     allocsize = 64;
        size_t          entrysize;
 
-       if ((dirdesc = opendir(dirname)) == NULL)
-               pg_log(PG_FATAL, "could not open directory \"%s\": %s\n", dirname, getErrorText(errno));
+       *namelist = (struct dirent **)
+               pg_malloc(allocsize * sizeof(struct dirent *));
 
-       *namelist = NULL;
+       if ((dirdesc = opendir(dirname)) == NULL)
+               pg_log(PG_FATAL, "could not open directory \"%s\": %s\n",
+                          dirname, getErrorText(errno));
 
-       while ((direntry = readdir(dirdesc)) != NULL)
+       while (errno = 0, (direntry = readdir(dirdesc)) != NULL)
        {
-               count++;
-
-               *namelist = (struct dirent **) realloc((void *) (*namelist),
-                                               (size_t) ((name_num + 1) * sizeof(struct dirent *)));
-
-               if (*namelist == NULL)
+               if (count >= allocsize)
                {
-                       closedir(dirdesc);
-                       return -1;
+                       allocsize *= 2;
+                       *namelist = (struct dirent **)
+                               pg_realloc(*namelist, allocsize * sizeof(struct dirent *));
                }
 
-               entrysize = sizeof(struct dirent) - sizeof(direntry->d_name) +
+               entrysize = offsetof(struct dirent, d_name) +
                        strlen(direntry->d_name) + 1;
 
-               (*namelist)[name_num] = (struct dirent *) malloc(entrysize);
-
-               if ((*namelist)[name_num] == NULL)
-               {
-                       closedir(dirdesc);
-                       return -1;
-               }
+               (*namelist)[count] = (struct dirent *) pg_malloc(entrysize);
 
-               memcpy((*namelist)[name_num], direntry, entrysize);
+               memcpy((*namelist)[count], direntry, entrysize);
 
-               name_num++;
+               count++;
        }
 
+#ifdef WIN32
+       /*
+        * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
+        * released version
+        */
+       if (GetLastError() == ERROR_NO_MORE_FILES)
+               errno = 0;
+#endif
+
+       if (errno)
+               pg_log(PG_FATAL, "could not read directory \"%s\": %s\n",
+                          dirname, getErrorText(errno));
+
        closedir(dirdesc);
 
        return count;

diff --git a/contrib/pg_upgrade/pg_upgrade.h b/contrib/pg_upgrade/pg_upgrade.h
index 3274227a0a3d516f8ae2b06bfa9fe0152d497e69..4f74c217eed1a9688552cb9719f9e9e75b11febb 100644 (file)
--- a/contrib/pg_upgrade/pg_upgrade.h
+++ b/contrib/pg_upgrade/pg_upgrade.h
@@ -429,7 +429,8 @@ prep_status(const char *fmt,...)
 __attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
 void           check_ok(void);
 char      *pg_strdup(const char *s);
-void      *pg_malloc(int size);
+void      *pg_malloc(size_t size);
+void      *pg_realloc(void *ptr, size_t size);
 void           pg_free(void *ptr);
 const char *getErrorText(int errNum);
 unsigned int str2uint(const char *str);

diff --git a/contrib/pg_upgrade/util.c b/contrib/pg_upgrade/util.c
index 6977663b63aabca1fff8ff6703461742815278e3..76cd20b23d70869cafa77c1036f559a5d9b1d107 100644 (file)
--- a/contrib/pg_upgrade/util.c
+++ b/contrib/pg_upgrade/util.c
@@ -183,7 +183,7 @@ get_user_info(char **user_name)
 
 
 void *
-pg_malloc(int n)
+pg_malloc(size_t n)
 {
        void       *p = malloc(n);
 
@@ -193,6 +193,17 @@ pg_malloc(int n)
        return p;
 }
 
+void *
+pg_realloc(void *ptr, size_t n)
+{
+       void       *p = realloc(ptr, n);
+
+       if (p == NULL)
+               pg_log(PG_FATAL, "%s: out of memory\n", os_info.progname);
+
+       return p;
+}
+
 
 void
 pg_free(void *p)