[PATCH:xrdb] Use reallocarray() for array allocations & resizing

[walter harms]

Am 11.08.2015 15:18, schrieb Matthieu Herrb:
> On Sun, Aug 09, 2015 at 04:21:42PM +0200, walter harms wrote:
>>
>>
>> Am 08.08.2015 18:04, schrieb Alan Coopersmith:
>>> Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
>>> ---
>>>  configure.ac |    2 +-
>>>  xrdb.c       |   39 +++++++++++++++++++++++++++++++++------
>>>  2 files changed, 34 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/configure.ac b/configure.ac
>>> index bf7e0a7..2c42add 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -37,7 +37,7 @@ m4_ifndef([XORG_MACROS_VERSION],
>>>  XORG_MACROS_VERSION(1.8)
>>>  XORG_DEFAULT_OPTIONS
>>>  
>>> -AC_CHECK_FUNCS([mkstemp asprintf])
>>> +AC_CHECK_FUNCS([mkstemp asprintf reallocarray])
>>>  
>>>  # Find MAXHOSTNAMELEN definition
>>>  # Common hidey holes:
>>> diff --git a/xrdb.c b/xrdb.c
>>> index a980230..72e526c 100644
>>> --- a/xrdb.c
>>> +++ b/xrdb.c
>>> @@ -53,6 +53,7 @@
>>>  #include <errno.h>
>>>  #include <stdlib.h>
>>>  #include <stdarg.h>
>>> +#include <stdint.h>
>>>  
>>>  #ifdef NEED_SYS_PARAM_H
>>>  # include <sys/param.h>         /* defines MAXHOSTNAMELEN on BSD & Linux */
>>> @@ -186,12 +187,27 @@ asprintf(char **ret, const char *format, ...)
>>>  }
>>>  #endif                          /* HAVE_ASPRINTF */
>>>  
>>> +#ifndef HAVE_REALLOCARRAY
>>> +/* overflow checking realloc API from OpenBSD libc */
>>> +static inline void *
>>> +reallocarray(void *optr, size_t n, size_t s)
>>> +{
>>> +    if (n > 0 && (SIZE_MAX / n) < s)
>>> +        return NULL;
>>> +    return realloc(optr, n * s);
>>> +}
>>> +#endif
>>
>>
>>
>> you could move the the fatal() into this function also.
>> That would remove the need to do so inside the code and
>> the need to review it :)
>>
> 
> For systems that have reallocarray() in libc, this would not work.

ups, i did not notice the HAVE_REALLOCARRAY propperly.
NTL the code allways fails on ENOMEM, a simple variation like
xreallocarray() would remove the need for error handling here.

re,
 wh



> 
>> just my 2 cents,
>>
>> re,
>>  wh
>>
>>> +
>>> +# define mallocarray(n, s) reallocarray(NULL, n, s)
>>> +
>>>  static void
>>>  InitBuffer(Buffer *b)
>>>  {
>>>      b->room = INIT_BUFFER_SIZE;
>>>      b->used = 0;
>>> -    b->buff = malloc(INIT_BUFFER_SIZE * sizeof(char));
>>> +    b->buff = mallocarray(INIT_BUFFER_SIZE, sizeof(char));
>>> +    if (b->buff == NULL)
>>> +        fatal("%s: Can't allocate memory in %s\n", ProgramName, __func__);
>>>  }
>>>  
>>>  #ifdef notyet
>>> @@ -206,7 +222,9 @@ static void
>>>  AppendToBuffer(Buffer *b, const char *str, size_t len)
>>>  {
>>>      while (b->used + len > b->room) {
>>> -        b->buff = realloc(b->buff, 2 * b->room * (sizeof(char)));
>>> +        b->buff = reallocarray(b->buff, b->room, 2 * sizeof(char));
>>> +        if (b->buff == NULL)
>>> +            fatal("%s: Can't allocate memory in %s\n", ProgramName, __func__);
>>>          b->room *= 2;
>>>      }
>>>      strncpy(b->buff + b->used, str, len);
>>> @@ -218,7 +236,10 @@ InitEntries(Entries *e)
>>>  {
>>>      e->room = INIT_ENTRY_SIZE;
>>>      e->used = 0;
>>> -    e->entry = malloc(INIT_ENTRY_SIZE * sizeof(Entry));
>>> +    e->entry = mallocarray(INIT_ENTRY_SIZE, sizeof(Entry));
>>> +    if (e->entry == NULL)
>>> +        fatal("%s: Can't allocate memory in %s\n", ProgramName, __func__);
>>> +
>>>  }
>>>  
>>>  static void
>>> @@ -258,7 +279,9 @@ AddEntry(Entries *e, Entry *entry)
>>>      }
>>>  
>>>      if (e->used == e->room) {
>>> -        e->entry = realloc(e->entry, 2 * e->room * (sizeof(Entry)));
>>> +        e->entry = reallocarray(e->entry, e->room, 2 * sizeof(Entry));
>>> +        if (e->entry == NULL)
>>> +            fatal("%s: Can't allocate memory in %s\n", ProgramName, __func__);
>>>          e->room *= 2;
>>>      }
>>>      entry->usable = True;
>>> @@ -1141,7 +1164,9 @@ main(int argc, char *argv[])
>>>      else {
>>>          Entries *dbs;
>>>  
>>> -        dbs = malloc(((unsigned) ScreenCount(dpy)) * sizeof(Entries));
>>> +        dbs = mallocarray(ScreenCount(dpy), sizeof(Entries));
>>> +        if (dbs == NULL)
>>> +            fatal("%s: Can't allocate memory in %s\n", ProgramName, __func__);
>>>          for (i = 0; i < ScreenCount(dpy); i++) {
>>>              Process(i, True, False);
>>>              dbs[i] = newDB;
>>> @@ -1425,7 +1450,9 @@ ShuffleEntries(Entries *db, Entries *dbs, unsigned int num)
>>>      Entries cur, cmp;
>>>      char *curtag, *curvalue;
>>>  
>>> -    hits = malloc(num * sizeof(int));
>>> +    hits = mallocarray(num, sizeof(int));
>>> +    if (hits == NULL)
>>> +        fatal("%s: Can't allocate memory in %s\n", ProgramName, __func__);
>>>      cur = dbs[0];
>>>      for (i = 0; i < cur.used; i++) {
>>>          curtag = cur.entry[i].tag;
>> _______________________________________________
>> xorg-devel at lists.x.org: X.Org development
>> Archives: http://lists.x.org/archives/xorg-devel
>> Info: http://lists.x.org/mailman/listinfo/xorg-devel
>