/* Get core for the memory region specified by MDP, using SIZE as the
amount to either add to or subtract from the existing region. Works
- like sbrk(), but using mmap(). */
+ like sbrk(), but using mmap().
+
+ It never returns NULL. Instead, it dies verbosely on errors. */
void *mmorecore(struct mdesc *mdp, int size)
{
ssize_t test = 0;
- void *result = NULL;
+ void *result; // please keep it uninitialized to track issues
off_t foffset; /* File offset at which new mapping will start */
size_t mapbytes; /* Number of bytes to map */
void *moveto; /* Address where we wish to move "break value" to */
} else if (size < 0) {
/* We are deallocating memory. If the amount requested would cause
us to try to deallocate back past the base of the mmap'd region
- then do nothing, and return NULL. Otherwise, deallocate the
- memory and return the old break value. */
+ then die verbosely. Otherwise, deallocate the memory and return
+ the old break value. */
if (((char *) mdp->breakval) + size >= (char *) mdp->base) {
result = (void *) mdp->breakval;
mdp->breakval = (char *) mdp->breakval + size;
munmap(moveto,
(size_t) (((char *) mdp->top) - ((char *) moveto)) - 1);
mdp->top = moveto;
+ } else {
+ fprintf(stderr,"Internal error: mmap was asked to deallocate more memory than it previously allocated. Bailling out now!\n");
+ abort();
}
} else {
/* We are allocating memory. Make sure we have an open file
descriptor if not working with anonymous memory. */
if (!(mdp->flags & MMALLOC_ANONYMOUS) && mdp->fd < 0) {
- THROWF(system_error,0,"mmap file descriptor <0 (%d), without MMALLOC_ANONYMOUS being in the flags",mdp->fd);
- result = NULL;
+ fprintf(stderr,"Internal error: mmap file descriptor <0 (%d), without MMALLOC_ANONYMOUS being in the flags.\n",mdp->fd);
+ abort();
} else if ((char *) mdp->breakval + size > (char *) mdp->top) {
/* The request would move us past the end of the currently
mapped memory, so map in enough more memory to satisfy
/* FIXME: Test results of lseek() */
lseek(mdp->fd, foffset + mapbytes - 1, SEEK_SET);
test = write(mdp->fd, &buf, 1);
- if (test == -1)
- THROWF(system_error, 0, "write to mmap'ed fd failed! error: %s", strerror(errno));
+ if (test == -1) {
+ fprintf(stderr,"Internal error: write to mmap'ed fd failed! error: %s", strerror(errno));
+ abort();
+ }
}
/* Let's call mmap. Note that it is possible that mdp->top
MAP_PRIVATE_OR_SHARED(mdp) | MAP_IS_ANONYMOUS(mdp) |
MAP_FIXED, MAP_ANON_OR_FD(mdp), foffset);
- if (mapto == (void *) -1/* That's MAP_FAILED */)
- THROWF(system_error,0,"mmap returned MAP_FAILED! error: %s",strerror(errno));
+ if (mapto == (void *) -1/* That's MAP_FAILED */) {
+ fprintf(stderr,"Internal error: mmap returned MAP_FAILED! error: %s",strerror(errno));
+ abort();
+ }
if (mdp->top == 0)
mdp->base = mdp->breakval = mapto;