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authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2009-10-25 04:35:22 +0100
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2009-10-25 04:35:22 +0100
commit77c066ea5cf4b1ee606a81e48388ff0b1d019134 (patch)
treeb51b001a013a4be3a2ad09fdc22cfdccf29bdbaf /modutils/modutils.c
parent30f3c1d5fdf8999491a01cb3fe8be8a40da52a75 (diff)
downloadbusybox-77c066ea5cf4b1ee606a81e48388ff0b1d019134.tar.gz
busybox-77c066ea5cf4b1ee606a81e48388ff0b1d019134.tar.bz2
modutils: add FEATURE_INSMOD_TRY_MMAP option
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>
Diffstat (limited to 'modutils/modutils.c')
-rw-r--r--modutils/modutils.c63
1 files changed, 53 insertions, 10 deletions
diff --git a/modutils/modutils.c b/modutils/modutils.c
index 969926db9..850a8683b 100644
--- a/modutils/modutils.c
+++ b/modutils/modutils.c
@@ -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;
}