open-dsi
/
clamav
mirror of https://github.com/Cisco-Talos/clamav
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

fuck mmap_sem!

Browse Source
0.96
acab 16 years ago
parent ee1b2a6c81
commit 5a078ca98c
1 changed files with 104 additions and 19 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 123
      libclamav/fmap.c

123
libclamav/fmap.c
Unescape View File

@ -37,6 +37,9 @@
#endif
#endif
#include <pthread.h>
#include "others.h"
#include "cltypes.h"
@ -54,9 +57,14 @@
/* FIXME: tune this stuff */
#define UNPAGE_THRSHLD_LO 4*1024*1024
#define UNPAGE_THRSHLD_HI 8*1024*1024
#define DUMB_SIZE 1*1024*1024
#define READAHEAD_PAGES 8
/* FIXME: remove the malloc fallback, it only makes thing slower */
#define DUMB_SIZE 0
/* DON'T ASK ME */
pthread_mutex_t fmap_mutex = PTHREAD_MUTEX_INITIALIZER;
#define READAHEAD_PAGES 4
static unsigned int fmap_align_items(unsigned int sz, unsigned int al) {
return sz / al + (sz % al != 0);
@ -99,10 +107,15 @@ struct F_MAP *fmap(int fd, off_t offset, size_t len) {
mapsz = pages * pgsz + hdrsz;
#if HAVE_MMAP
if(mapsz >= DUMB_SIZE) {
if ((m = (struct F_MAP *)mmap(NULL, mapsz, PROT_READ | PROT_WRITE, MAP_PRIVATE|ANONYMOUS_MAP, -1, 0)) == MAP_FAILED)
pthread_mutex_lock(&fmap_mutex);
if ((m = (struct F_MAP *)mmap(NULL, mapsz, PROT_READ | PROT_WRITE, MAP_PRIVATE|/*FIXME: MAP_POPULATE is ~8% faster but more memory intensive */ANONYMOUS_MAP, -1, 0)) == MAP_FAILED)
m = NULL;
else
else {
dumb = 0;
madvise(m, mapsz, MADV_RANDOM|MADV_DONTFORK);
madvise(m, hdrsz, MADV_WILLNEED);
}
pthread_mutex_unlock(&fmap_mutex);
} else
#endif
m = (struct F_MAP *)cli_malloc(mapsz);
@ -120,7 +133,13 @@ struct F_MAP *fmap(int fd, off_t offset, size_t len) {
m->pgsz = pgsz;
m->paged = 0;
memset(m->bitmap, 0, sizeof(uint32_t) * pages);
// cli_errmsg("FMAPDBG: created %p - len %u pages %u hdrsz %u\n", m, len, pages, hdrsz);
#ifdef FMAPDEBUG
m->page_needs = 0;
m->page_reads = 0;
m->page_locks = 0;
m->page_unlocks = 0;
m->page_unmaps = 0;
#endif
return m;
}
@ -179,8 +198,13 @@ static void fmap_aging(struct F_MAP *m) {
m->bitmap[freeme[i]] = FM_MASK_SEEN;
m->paged--;
/* and we mmap the page over so the kernel knows there's nothing good in there */
pthread_mutex_lock(&fmap_mutex);
if(mmap(pptr, m->pgsz, PROT_READ | PROT_WRITE, MAP_FIXED|MAP_PRIVATE|ANONYMOUS_MAP, -1, 0) == MAP_FAILED)
cli_warnmsg("fmap_aging: kernel hates you\n");
pthread_mutex_unlock(&fmap_mutex);
#ifdef FMAPDEBUG
m->page_unmaps++;
#endif
}
}
free(freeme);
@ -192,9 +216,16 @@ static void fmap_aging(struct F_MAP *m) {
static int fmap_readpage(struct F_MAP *m, unsigned int first_page, unsigned int count, unsigned int lock_count) {
size_t readsz = 0, got;
char *pptr = NULL;
uint32_t s;
volatile uint32_t s;
unsigned int i, page = first_page, force_read = 0;
for(i=0; i<count; i++) { /* REAL MEN DON'T MADVISE: seriously, it sucks! */
volatile char faultme = ((char *)m)[(first_page+i) * m->pgsz + m->hdrsz];
}
#ifdef FMAPDEBUG
m->page_needs += count;
m->page_locks += lock_count;
#endif
for(i=0; i<=count; i++, page++) {
int lock;
if(lock_count) {
@ -254,6 +285,9 @@ static int fmap_readpage(struct F_MAP *m, unsigned int first_page, unsigned int
cli_warnmsg("pread fail: page %u pages %u map-offset %lu - asked for %lu bytes, got %lu\n", first_page, m->pages, (long unsigned int)m->offset, (long unsigned int)readsz, (long unsigned int)got);
return 1;
}
#ifdef FMAPDEBUG
m->page_reads += count;
#endif
pptr = NULL;
force_read = 0;
readsz = 0;
@ -285,12 +319,12 @@ static void *fmap_need(struct F_MAP *m, size_t at, size_t len, int lock) {
char *ret;
if(!len) {
cli_warnmsg("fmap: attempted void need\n");
// cli_warnmsg("fmap: attempted void need\n");
return NULL;
}
if(!CLI_ISCONTAINED(0, m->len, at, len)) {
cli_warnmsg("fmap: attempted oof need\n");
// cli_warnmsg("fmap: attempted oof need\n");
return NULL;
}
@ -304,8 +338,6 @@ static void *fmap_need(struct F_MAP *m, size_t at, size_t len, int lock) {
if(last_page >= m->pages) last_page = m->pages - 1;
#endif
// cli_errmsg("FMAPDBG: +++ map %p - len %u lock: %d (page %u to %u)\n", m, len, lock, first_page, last_page);
if(fmap_readpage(m, first_page, last_page-first_page+1, lock_count))
return NULL;
@ -315,19 +347,15 @@ static void *fmap_need(struct F_MAP *m, size_t at, size_t len, int lock) {
}
void *fmap_need_off(struct F_MAP *m, size_t at, size_t len) {
// cli_errmsg("FMAPDBG: need_off map %p at %u len %u\n", m, at, len);
return fmap_need(m, at, len, 1);
}
void *fmap_need_off_once(struct F_MAP *m, size_t at, size_t len) {
// cli_errmsg("FMAPDBG: need_off_once map %p at %u len %u\n", m, at, len);
return fmap_need(m, at, len, 0);
}
void *fmap_need_ptr(struct F_MAP *m, void *ptr, size_t len) {
// cli_errmsg("FMAPDBG: need_ptr map %p at %p len %u\n", m, ptr, len);
return fmap_need_off(m, (char *)ptr - (char *)m - m->hdrsz, len);
}
void *fmap_need_ptr_once(struct F_MAP *m, void *ptr, size_t len) {
// cli_errmsg("FMAPDBG: need_ptr_once map %p at %p len %u\n", m, ptr, len);
return fmap_need_off_once(m, (char *)ptr - (char *)m - m->hdrsz, len);
}
@ -339,11 +367,12 @@ void *fmap_need_str(struct F_MAP *m, void *ptr, size_t len_hint) {
static void fmap_unneed_page(struct F_MAP *m, unsigned int page) {
uint32_t s = m->bitmap[page];
// cli_errmsg("FMAPDBG: --- map %p - page %u status %u count %u\n", m, page, s>>30, s & FM_MASK_COUNT);
if((s & (FM_MASK_PAGED | FM_MASK_LOCKED)) == (FM_MASK_PAGED | FM_MASK_LOCKED)) {
/* page is paged and locked: check lock count */
s &= FM_MASK_COUNT;
#ifdef FMAPDEBUG
m->page_unlocks ++;
#endif
if(s > 1) /* locked more than once: dec lock count */
m->bitmap[page]--;
else if (s == 1) /* only one lock left: unlock and begin aging */
@ -399,10 +428,16 @@ int fmap_readn(struct F_MAP *m, void *dst, size_t at, size_t len) {
}
void fmunmap(struct F_MAP *m) {
#ifdef FMAPDEBUG
cli_errmsg("FMAPDEBUG: Needs:%u reads:%u locks:%u unlocks:%u unmaps:%u\n", m->page_needs, m->page_reads, m->page_locks, m->page_unlocks, m->page_unmaps);
#endif
#if HAVE_MMAP
if(!m->dumb) {
size_t len = m->pages * m->pgsz + m->hdrsz;
pthread_mutex_lock(&fmap_mutex);
munmap((void *)m, len);
pthread_mutex_unlock(&fmap_mutex);
} else
#endif
free((void *)m);
@ -416,7 +451,7 @@ void *fmap_need_offstr(struct F_MAP *m, size_t at, size_t len_hint) {
len_hint = m->len - at;
if(!CLI_ISCONTAINED(0, m->len, at, len_hint)) {
cli_warnmsg("fmap: attempted oof need_str\n");
// cli_warnmsg("fmap: attempted oof need_str\n");
return NULL;
}
@ -435,11 +470,12 @@ void *fmap_need_offstr(struct F_MAP *m, size_t at, size_t len_hint) {
}
if(i == first_page) {
scanat = at % m->pgsz;
scansz = m->pgsz - scanat;
scansz = MIN(len_hint, m->pgsz - scanat);
} else {
scanat = 0;
scansz = m->pgsz;
scansz = MIN(len_hint, m->pgsz);
}
len_hint -= scansz;
if(memchr(&thispage[scanat], 0, scansz))
return ptr;
}
@ -447,3 +483,52 @@ void *fmap_need_offstr(struct F_MAP *m, size_t at, size_t len_hint) {
fmap_unneed_page(m, i);
return NULL;
}
void *fmap_gets(struct F_MAP *m, char *dst, size_t *at, size_t max_len) {
unsigned int i, first_page, last_page;
char *src = (void *)((char *)m + m->hdrsz + *at), *endptr = NULL;
size_t len = MIN(max_len-1, m->len - *at), fullen = len;
if(!len || !CLI_ISCONTAINED(0, m->len, *at, len)) {
//cli_warnmsg("fmap: attempted oof need_str\n");
return NULL;
}
fmap_aging(m);
first_page = fmap_which_page(m, *at);
last_page = fmap_which_page(m, *at + len - 1);
for(i=first_page; i<=last_page; i++) {
char *thispage = (char *)m + m->hdrsz + i * m->pgsz;
unsigned int scanat, scansz;
if(fmap_readpage(m, i, 1, 0))
return NULL;
if(i == first_page) {
scanat = *at % m->pgsz;
scansz = MIN(len, m->pgsz - scanat);
} else {
scanat = 0;
scansz = MIN(len, m->pgsz);
}
len -= scansz;
if((endptr = memchr(&thispage[scanat], '\n', scansz))) {
endptr++;
break;
}
}
if(endptr) {
memcpy(dst, src, endptr - src);
dst[endptr - src] = '\0';
*at += endptr - src;
} else {
memcpy(dst, src, fullen);
dst[fullen] = '\0';
*at += fullen;
}
return dst;
}

Write Preview
Loading…
Cancel
Save