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

diff --git a/modutils/depmod.c b/modutils/depmod.c
index 489a0330e5076a7cd54ad3fcf12de274100d8b6e..5d51ba450d71587077a7c618ec46b6e267a60e5e 100644 (file)
--- a/modutils/depmod.c
+++ b/modutils/depmod.c
@@ -11,6 +11,12 @@
 #include <libbb.h>
 #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 {
        llist_t *lst;
 };
@@ -25,40 +31,56 @@ static int fill_lst(const char *modulename, struct stat ATTRIBUTE_UNUSED *sb,
        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)
 {
-       size_t seen = 0;
-       size_t len = MAXINT(ssize_t);
-       void *the_module = xmalloc_open_read_close(fname, &len), *ptr = the_module;
-       const char *deps;
-       RESERVE_CONFIG_BUFFER(depends, 512);
-       RESERVE_CONFIG_BUFFER(buf1, 512);
-
-       memset(depends, 0, sizeof(depends));
+       size_t len = sb->st_size;
+       void *the_module, *ptr;
+       int fd;
+       char *depends, *deps;
 
+/*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 */
-               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);
-//bb_info_msg("[%d] fname='%s'", (int)data, fname);
+//bb_info_msg("fname='%s'", fname);
        do {
                /* search for a 'd' */
-               ptr = memchr(ptr, 'd', len - seen);
+               ptr = memchr(ptr, 'd', len);
                if (ptr == NULL) /* no d left, done */
+                       goto done;
+               if (memcmp(ptr, "depends=", sizeof("depends=")-1) == 0)
                        break;
-               if (sscanf(ptr, "depends=%s", depends) == 1)
-                       break;
-               seen = ++ptr - the_module;
+               len -= ++ptr - the_module;
        } while (1);
+       deps = depends = strdup (ptr + sizeof("depends=")-1);
 //bb_info_msg(" depends='%s'", depends);
-       deps = depends;
        while (*deps) {
                llist_t * _lst = G.lst;
+               char *buf1;
+
                ptr = strchr(deps, ',');
                if (ptr != NULL)
                        *(char*)ptr = '\0';
                /* remember the length of the current dependency plus eventual 0 byte */
                len = strlen(deps) + (ptr != NULL);
+               buf1 = xmalloc(len + 3);
                sprintf(buf1, "/%s.", deps); /* make sure we match the correct file */
                while (_lst) {
                        ptr = strstr(_lst->data, buf1);
@@ -66,16 +88,17 @@ static int fileAction(const char *fname, struct stat ATTRIBUTE_UNUSED *sb,
                                break; /* found it */
                        _lst = _lst->link;
                }
-               if (_lst && _lst->data) {
+               free(buf1);
+               if (_lst /*&& _lst->data*/) {
 //bb_info_msg("[%s] -> '%s'", deps, _lst->data);
                        fprintf((FILE*)data, " %s", _lst->data);
                        deps += len;
                }
        }
+       free(depends);
 done:
-       RELEASE_CONFIG_BUFFER(depends);
-       RELEASE_CONFIG_BUFFER(buf1);
-       free(the_module);
+       munmap(the_module, sb->st_size);
+skip:
        return TRUE;
 }