checkpath.c: Hoist the `buf' used for link targets for reuse.

[checkpath] / checkpath.c

diff --git a/checkpath.c b/checkpath.c
index 5c047a595ebea34a561cd2359ce8dc4baf87502b..d874246025f69ed4b69fe14259226569304a88fa 100644 (file)
--- a/checkpath.c
+++ b/checkpath.c
@@ -59,16 +59,14 @@ struct elt {
   struct elt *e_link;                  /* Pointer to the next one along */
   size_t e_offset;                     /* Offset of name in path string */
   unsigned e_flags;                    /* Various useful flags */
+#define EF_STICKY 1u                   /*   Directory has sticky bit set */
   char e_name[1];                      /* Name of the directory */
 };
 
-#define f_sticky 1u                    /* Directory has sticky bit set */
-
-#define f_last 1u                      /* This is the final item to check */
 
 /*----- Static variables --------------------------------------------------*/
 
-static struct elt rootnode = { 0, 0, 0 }; /* Root of the list */
+static const struct elt rootnode = { 0, 0, 0 }; /* Root of the list */
 static struct elt *sp;                 /* Stack pointer for list */
 static dstr d = DSTR_INIT;             /* Current path string */
 
@@ -139,7 +137,7 @@ static void pop(void)
     struct elt *e = sp->e_link;
     d.len = sp->e_offset;
     DPUTZ(&d);
-    free(sp); sp = e;
+    xfree(sp); sp = e;
   }
 }
 
@@ -272,13 +270,17 @@ static void report(const struct checkpath *cp, unsigned what, int verbose,
  * Arguments:  @const char *p@ = name of directory to check
  *             @struct stat *st@ = pointer to @stat@(2) block for it
  *             @const struct checkpath *cp@ = pointer to caller parameters
- *             @unsigned f@ = various flags
+ *             @unsigned f@ = various flags (@SF_...@)
  *
  * Returns:    Zero if everything's OK, else bitmask of problems.
  *
  * Use:                Performs the main load of sanity-checking on a directory.
+ *             If @SF_LAST@ is not set then sticky directories are always
+ *             acceptable.
  */
 
+#define SF_LAST 1u                     /* This is the final item to check */
+
 static unsigned sanity(const char *p, struct stat *st,
                       const struct checkpath *cp, unsigned f)
 {
@@ -288,13 +290,13 @@ static unsigned sanity(const char *p, struct stat *st,
   unsigned b;
 
   if (S_ISDIR(st->st_mode) &&
-      (!(f & f_last) || (cp->cp_what & CP_STICKYOK)))
-    stickyok = 01000;
+      (!(f & SF_LAST) || (cp->cp_what & CP_STICKYOK)))
+    stickyok = S_ISVTX;
 
   /* --- Check for world-writability --- */
 
   if ((cp->cp_what & CP_WRWORLD) &&
-      (st->st_mode & (0002 | stickyok)) == 0002) {
+      (st->st_mode & (S_IWOTH | stickyok)) == S_IWOTH) {
     bad |= CP_WRWORLD;
     report(cp, CP_WRWORLD, 1, p, "** world writable **");
   }
@@ -302,7 +304,7 @@ static unsigned sanity(const char *p, struct stat *st,
   /* --- Check for group-writability --- */
 
   if ((cp->cp_what & (CP_WRGRP | CP_WROTHGRP)) &&
-      (st->st_mode & (0020 | stickyok)) == 0020) {
+      (st->st_mode & (S_IWGRP | stickyok)) == S_IWGRP) {
     b = CP_WRGRP;
 
     if (cp->cp_what & CP_WROTHGRP) {
@@ -350,10 +352,11 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
   struct elt *e, *ee;
   struct stat st;
   unsigned bad = 0;
+  dstr buf = DSTR_INIT;
 
   /* --- Initialize stack pointer and path string --- */
 
-  sp = &rootnode;
+  sp = (/*unconst*/ struct elt *)&rootnode;
   dstr_destroy(&d);
 
   /* --- Try to find the current directory --- */
@@ -387,7 +390,7 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
     /* --- Strip off simple `.' elements --- */
 
     if (strcmp(ee->e_name, ".") == 0) {
-      free(ee);
+      xfree(ee);
       ee = e;
       continue;
     }
@@ -396,7 +399,7 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
 
     else if (strcmp(ee->e_name, "..") == 0) {
       pop();
-      free(ee);
+      xfree(ee);
       ee = e;
       continue;
     }
@@ -417,11 +420,11 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
     /* --- Handle symbolic links specially --- */
 
     if (S_ISLNK(st.st_mode)) {
-      dstr buf = DSTR_INIT;
       int i;
 
       /* --- Resolve the link --- */
 
+      dstr_reset(&buf);
       dstr_ensure(&buf, st.st_size + 1);
       if ((i = readlink(d.buf, buf.buf, buf.sz)) < 0) {
        report(cp, CP_ERROR, 0, d.buf, "can't readlink: %e");
@@ -439,7 +442,7 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
        */
 
       if ((cp->cp_what & CP_WROTHUSR) &&
-         (sp->e_link->e_flags & f_sticky) &&
+         (sp->e_link->e_flags & EF_STICKY) &&
          st.st_uid != cp->cp_uid && st.st_uid != 0) {
        bad |= CP_WROTHUSR;
        report(cp, CP_WROTHUSR, 1, d.buf,
@@ -453,17 +456,16 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
       else
        pop();
       ee = splitpath(buf.buf, ee);
-      dstr_destroy(&buf);
       continue;
     }
 
     /* --- Run the sanity check on this path element --- */
 
-    bad |= sanity(d.buf, &st, cp, ee ? 0 : f_last);
+    bad |= sanity(d.buf, &st, cp, ee ? 0 : SF_LAST);
 
     if (S_ISDIR(st.st_mode)) {
-      if (st.st_mode & 01000)
-       sp->e_flags |= f_sticky;
+      if (st.st_mode & S_ISVTX)
+       sp->e_flags |= EF_STICKY;
       report(cp, CP_REPORT, 4, d.buf, "directory");
       continue;
     }
@@ -480,12 +482,13 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
       report(cp, CP_ERROR, 0, 0, "junk left over after reaching leaf");
     while (ee) {
       e = ee->e_link;
-      free(ee);
+      xfree(ee);
       ee = e;
     }
   }
 
   popall();
+  dstr_destroy(&buf);
   return (bad);
 }