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- use mmap instead of allocating hundreds of megabytes of RAM. +39b

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This commit is contained in:
Bernhard Reutner-Fischer 2008-05-26 15:12:01 +00:00
parent dc5d7fec35
commit cf18010ca9
1 changed files with 43 additions and 20 deletions
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63
modutils/depmod.c
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@ -11,6 +11,12 @@
#include <libbb.h> #include <libbb.h>
#include <sys/utsname.h> /* uname() */ #include <sys/utsname.h> /* uname() */
/*
* Theory of operation:
* - iterate over all modules and record their full path
* - iterate over all modules looking for "depends=" entries
* for each depends, look through our list of full paths and emit if found
*/
struct globals { struct globals {
llist_t *lst; llist_t *lst;
}; };
@ -25,40 +31,56 @@ static int fill_lst(const char *modulename, struct stat ATTRIBUTE_UNUSED *sb,
return TRUE; return TRUE;
} }
static int fileAction(const char *fname, struct stat ATTRIBUTE_UNUSED *sb, static int fileAction(const char *fname, struct stat *sb,
void *data, int ATTRIBUTE_UNUSED depth) void *data, int ATTRIBUTE_UNUSED depth)
{ {
size_t seen = 0; size_t len = sb->st_size;
size_t len = MAXINT(ssize_t); void *the_module, *ptr;
void *the_module = xmalloc_open_read_close(fname, &len), *ptr = the_module; int fd;
const char *deps; char *depends, *deps;
RESERVE_CONFIG_BUFFER(depends, 512);
RESERVE_CONFIG_BUFFER(buf1, 512);
memset(depends, 0, sizeof(depends));
/*XXX: FIXME: does not handle compressed modules!
* There should be a function that looks at the extension and sets up
* open_transformer for us.
*/
if (last_char_is(fname, 'o') == NULL) /* not a module */ if (last_char_is(fname, 'o') == NULL) /* not a module */
goto done; goto skip;
fd = xopen(fname, O_RDONLY);
the_module = mmap(NULL, len, PROT_READ, MAP_SHARED
#if defined MAP_POPULATE
|MAP_POPULATE
#endif
, fd, 0);
close(fd);
if (the_module == MAP_FAILED)
bb_perror_msg_and_die("mmap");
ptr = the_module;
fprintf((FILE*)data, "\n%s:", fname); fprintf((FILE*)data, "\n%s:", fname);
//bb_info_msg("[%d] fname='%s'", (int)data, fname); //bb_info_msg("fname='%s'", fname);
do { do {
/* search for a 'd' */ /* search for a 'd' */
ptr = memchr(ptr, 'd', len - seen); ptr = memchr(ptr, 'd', len);
if (ptr == NULL) /* no d left, done */ if (ptr == NULL) /* no d left, done */
goto done;
if (memcmp(ptr, "depends=", sizeof("depends=")-1) == 0)
break; break;
if (sscanf(ptr, "depends=%s", depends) == 1) len -= ++ptr - the_module;
break;
seen = ++ptr - the_module;
} while (1); } while (1);
deps = depends = strdup (ptr + sizeof("depends=")-1);
//bb_info_msg(" depends='%s'", depends); //bb_info_msg(" depends='%s'", depends);
deps = depends;
while (*deps) { while (*deps) {
llist_t * _lst = G.lst; llist_t * _lst = G.lst;
char *buf1;
ptr = strchr(deps, ','); ptr = strchr(deps, ',');
if (ptr != NULL) if (ptr != NULL)
*(char*)ptr = '\0'; *(char*)ptr = '\0';
/* remember the length of the current dependency plus eventual 0 byte */ /* remember the length of the current dependency plus eventual 0 byte */
len = strlen(deps) + (ptr != NULL); len = strlen(deps) + (ptr != NULL);
buf1 = xmalloc(len + 3);
sprintf(buf1, "/%s.", deps); /* make sure we match the correct file */ sprintf(buf1, "/%s.", deps); /* make sure we match the correct file */
while (_lst) { while (_lst) {
ptr = strstr(_lst->data, buf1); ptr = strstr(_lst->data, buf1);
@ -66,16 +88,17 @@ static int fileAction(const char *fname, struct stat ATTRIBUTE_UNUSED *sb,
break; /* found it */ break; /* found it */
_lst = _lst->link; _lst = _lst->link;
} }
if (_lst && _lst->data) { free(buf1);
if (_lst /*&& _lst->data*/) {
//bb_info_msg("[%s] -> '%s'", deps, _lst->data); //bb_info_msg("[%s] -> '%s'", deps, _lst->data);
fprintf((FILE*)data, " %s", _lst->data); fprintf((FILE*)data, " %s", _lst->data);
deps += len; deps += len;
} }
} }
free(depends);
done: done:
RELEASE_CONFIG_BUFFER(depends); munmap(the_module, sb->st_size);
RELEASE_CONFIG_BUFFER(buf1); skip:
free(the_module);
return TRUE; return TRUE;
} }