ahp/busybox
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

modutils: add FEATURE_INSMOD_TRY_MMAP option

Browse source 
function                                             old     new   delta
try_to_mmap_module                                     -     121    +121
bb_init_module_24                                   4514    4578     +64
bb_init_module                                       119     173     +54
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/0 up/down: 239/0)             Total: 239 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-10-25 04:35:22 +01:00
parent 30f3c1d5fd
commit 77c066ea5c
4 changed files with 92 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

63
modutils/modutils.c
View file

@ -62,7 +62,7 @@ char* FAST_FUNC filename2modname(const char *filename, char *modname)
return modname;
}
char * FAST_FUNC parse_cmdline_module_options(char **argv)
char* FAST_FUNC parse_cmdline_module_options(char **argv)
{
char *options;
int optlen;
@ -77,6 +77,40 @@ char * FAST_FUNC parse_cmdline_module_options(char **argv)
return options;
}
#if ENABLE_FEATURE_INSMOD_TRY_MMAP
void* FAST_FUNC try_to_mmap_module(const char *filename, size_t *image_size_p)
{
/* We have user reports of failure to load 3MB module
* on a 16MB RAM machine. Apparently even a transient
* memory spike to 6MB during module load
* is too big for that system. */
void *image;
struct stat st;
int fd;
fd = xopen(filename, O_RDONLY);
fstat(fd, &st);
image = NULL;
/* st.st_size is off_t, we can't just pass it to mmap */
if (st.st_size <= *image_size_p) {
size_t image_size = st.st_size;
image = mmap(NULL, image_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (image == MAP_FAILED) {
image = NULL;
} else if (*(uint32_t*)image != SWAP_BE32(0x7f454C46)) {
/* No ELF signature. Compressed module? */
munmap(image, image_size);
image = NULL;
} else {
/* Success. Report the size */
*image_size_p = image_size;
}
}
close(fd);
return image;
}
#endif
/* Return:
* 0 on success,
* -errno on open/read error,
@ -84,9 +118,10 @@ char * FAST_FUNC parse_cmdline_module_options(char **argv)
*/
int FAST_FUNC bb_init_module(const char *filename, const char *options)
{
size_t len;
size_t image_size;
char *image;
int rc;
bool mmaped;
if (!options)
options = "";
@ -97,17 +132,25 @@ int FAST_FUNC bb_init_module(const char *filename, const char *options)
return bb_init_module_24(filename, options);
#endif
/* Use the 2.6 way */
len = INT_MAX - 4095;
errno = ENOMEM; /* may be changed by e.g. open errors below */
image = xmalloc_open_zipped_read_close(filename, &len);
if (!image)
return -errno;
image_size = INT_MAX - 4095;
mmaped = 0;
image = try_to_mmap_module(filename, &image_size);
if (image) {
mmaped = 1;
} else {
errno = ENOMEM; /* may be changed by e.g. open errors below */
image = xmalloc_open_zipped_read_close(filename, &image_size);
if (!image)
return -errno;
}
errno = 0;
init_module(image, len, options);
init_module(image, image_size, options);
rc = errno;
free(image);
if (mmaped)
munmap(image, image_size);
else
free(image);
return rc;
}