From e6b3ac496f8b72f089247e93e6892bb6fa094976 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Mon, 9 Mar 2020 22:07:47 -0700
Subject: modinfo: various fixes.

I came here because the new -Wno-unreachable-code-loop-increment warning
didn't like the for loop on line 86. That loop is indeed not necessary.

Use strend() to do a string suffix match.

Use memmem() to search. It's available on macOS and Android by default,
but it's behind _GNU_SOURCE for glibc, so add that to portability.h.

Output the tags in the same order as the Debian modinfo.

I've left "parmtype" in even though the Debian modinfo doesn't output it
at all.

Also fix the tests so that they work on a device that has modules for
multiple kernels installed (like my laptop) --- make sure that the two
modules we pick come from the same kernel.
---
 toys/other/modinfo.c | 67 +++++++++++++++++++++++-----------------------------
 1 file changed, 30 insertions(+), 37 deletions(-)

(limited to 'toys/other')

diff --git a/toys/other/modinfo.c b/toys/other/modinfo.c
index 286570f1..6c1e9392 100644
--- a/toys/other/modinfo.c
+++ b/toys/other/modinfo.c
@@ -40,16 +40,16 @@ static void output_field(char *field, char *value)
 
 static void modinfo_file(char *full_name)
 {
-  int fd, len, i;
-  char *buf = 0, *pos, *modinfo_tags[] = {
-    "alias", "license", "description", "author", "firmware",
-    "vermagic", "srcversion", "intree", "depends", "parm",
-    "parmtype",
+  int fd, flen, i;
+  char *buf = 0, *end, *modinfo_tags[] = {
+    "license", "author", "description", "firmware", "alias", "srcversion",
+    "depends", "retpoline", "intree", "name", "vermagic", "parm", "parmtype",
   };
 
   if (-1 != (fd = open(full_name, O_RDONLY))) {
-    len = fdlength(fd);
-    buf = xmmap(0, len, PROT_READ, MAP_SHARED, fd, 0);
+    flen = fdlength(fd);
+    buf = xmmap(0, flen, PROT_READ, MAP_SHARED, fd, 0);
+    end = buf + flen;
     close(fd);
   }
 
@@ -61,47 +61,42 @@ static void modinfo_file(char *full_name)
   TT.count++;
   output_field("filename", full_name);
 
-  for (pos = buf; pos < buf+len; pos++) {
-    if (*pos) continue;
+  for (i=0; i<ARRAY_LEN(modinfo_tags); i++) {
+    char *field = modinfo_tags[i], *p = buf;
+    int slen = sprintf(toybuf, "%s=", field);
 
-    for (i=0; i<ARRAY_LEN(modinfo_tags); i++) {
-      char *str = modinfo_tags[i];
-      int len = strlen(str);
-
-      if (!strncmp(pos+1, str, len) && pos[len+1] == '=')
-        output_field(str, pos+len+2);
+    while (p && p < end) {
+      p = memmem(p, end-p, toybuf, slen);
+      if (p) output_field(field, p += slen);
     }
   }
 
-  munmap(buf, len);
+  munmap(buf, flen);
 }
 
 static int check_module(struct dirtree *new)
 {
-  if (!dirtree_notdotdot(new)) return 0;
+  char *s;
+  int len;
 
-  if (S_ISREG(new->st.st_mode)) {
-    char *s;
-
-    for (s = toys.optargs[TT.mod]; *s; s++) {
-      int len = 0;
+  if (!dirtree_notdotdot(new)) return 0;
 
-      // The kernel treats - and _ the same, so we should too.
-      for (len = 0; s[len]; len++) {
-        if (s[len] == '-' && new->name[len] == '_') continue;
-        if (s[len] == '_' && new->name[len] == '-') continue;
-        if (s[len] != new->name[len]) break;
-      }
-      if (s[len] || strcmp(new->name+len, ".ko")) break;
+  if (!S_ISREG(new->st.st_mode)) return DIRTREE_RECURSE;
 
-      modinfo_file(s = dirtree_path(new, 0));
-      free(s);
+  s = toys.optargs[TT.mod];
 
-      return DIRTREE_ABORT;
-    }
+  // The kernel treats - and _ the same, so we should too.
+  for (len = 0; s[len]; len++) {
+    if (s[len] == '-' && new->name[len] == '_') continue;
+    if (s[len] == '_' && new->name[len] == '-') continue;
+    if (s[len] != new->name[len]) break;
   }
+  if (s[len] || strcmp(new->name+len, ".ko")) return DIRTREE_RECURSE;
+
+  modinfo_file(s = dirtree_path(new, 0));
+  free(s);
 
-  return DIRTREE_RECURSE;
+  return DIRTREE_ABORT;
 }
 
 void modinfo_main(void)
@@ -120,9 +115,7 @@ void modinfo_main(void)
   }
 
   for (TT.mod = 0; TT.mod<toys.optc; TT.mod++) {
-    char *s = strstr(toys.optargs[TT.mod], ".ko");
-
-    if (s && !s[3]) modinfo_file(toys.optargs[TT.mod]);
+    if (strend(toys.optargs[TT.mod], ".ko")) modinfo_file(toys.optargs[TT.mod]);
     else {
       char *path = xmprintf("%s/lib/modules/%s", TT.b, TT.k);
 
-- 
cgit v1.2.3