Add readlink0() and readlinkat0() which null terminate the data.

2 files changed, 6 insertions, 11 deletions

diff --git a/toys/posix/cp.c b/toys/posix/cp.c
index 77e7f132..eafabcd1 100644
--- a/toys/posix/cp.c
+++ b/toys/posix/cp.c
@@ -251,8 +251,7 @@ int cp_node(struct dirtree *try)
 
         // make symlink, or make block/char/fifo/socket
         if (S_ISLNK(try->st.st_mode)
-            ? (0 < (i = readlinkat(tfd, try->name, toybuf, sizeof(toybuf))) &&
-               sizeof(toybuf) > i && !(toybuf[i] = '\0') &&
+            ? ((i = readlinkat0(tfd, try->name, toybuf, sizeof(toybuf))) &&
                !symlinkat(toybuf, cfd, catch))
             : !mknodat(cfd, catch, try->st.st_mode, try->st.st_rdev))
         {
diff --git a/toys/posix/ps.c b/toys/posix/ps.c
index 8ac6eef7..773f40c4 100644
--- a/toys/posix/ps.c
+++ b/toys/posix/ps.c
@@ -751,9 +751,8 @@ static int get_ps(struct dirtree *new)
       if (TT.threadparent && TT.threadparent->extra)
         ptb = (void *)TT.threadparent->extra;
 
-      if (j==3 && !ptb) {
-        if ((len = readlinkat(fd, buf, buf, len))<1) len = 0;
-      } else {
+      if (j==3 && !ptb) len = readlinkat0(fd, buf, buf, len);
+      else {
         if (j==3) i = strlen(s = ptb->str+ptb->offset[3]);
         else {
           if (!ptb || tb->slot[SLOT_argv0len]) ptb = tb;
@@ -766,8 +765,8 @@ static int get_ps(struct dirtree *new)
         }
         if (i<len) len = i;
         memcpy(buf, s, len);
+        buf[len] = 0;
       }
-      buf[len] = 0;
 
     // If it's not the TTY field, data we want is in a file.
     // Last length saved in slot[] is command line (which has embedded NULs)
@@ -782,11 +781,8 @@ static int get_ps(struct dirtree *new)
         for (i = 0; i<3; i++) {
           sprintf(buf, "%lld/fd/%i", *slot, i);
           if (!fstatat(fd, buf, &st, 0) && S_ISCHR(st.st_mode)
-            && st.st_rdev == rdev && 0<(len = readlinkat(fd, buf, buf, len)))
-          {
-            buf[len] = 0;
-            break;
-          }
+            && st.st_rdev == rdev && (len = readlinkat0(fd, buf, buf, len)))
+              break;
         }
 
         // Couldn't find it, try all the tty drivers.