linux: use __fd_to_filename helper function instead of snprintf.

Change made to fchmodat and fexecve. There are tests using xasprintf
instead of this helper as well, but this commit doesn't touch them.

diff --git a/sysdeps/unix/sysv/linux/fchmodat.c b/sysdeps/unix/sysv/linux/fchmodat.c
index f264f0c..5bd1eb9 100644 (file)
--- a/sysdeps/unix/sysv/linux/fchmodat.c
+++ b/sysdeps/unix/sysv/linux/fchmodat.c
@@ -18,6 +18,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <fd_to_filename.h>
 #include <not-cancel.h>
 #include <stdio.h>
 #include <sys/stat.h>
@@ -69,16 +70,8 @@ fchmodat (int fd, const char *file, mode_t mode, int flag)
 
       /* For most file systems, fchmod does not operate on O_PATH
         descriptors, so go through /proc.  */
-      char buf[32];
-      if (__snprintf (buf, sizeof (buf), "/proc/self/fd/%d", pathfd) < 0)
-       {
-         /* This also may report strange error codes to the caller
-            (although snprintf really should not fail).  */
-         __close_nocancel (pathfd);
-         return -1;
-       }
-
-      int ret = __chmod (buf, mode);
+      struct fd_to_filename filename;
+      int ret = __chmod (__fd_to_filename (pathfd, &filename), mode);
       if (ret != 0)
        {
          if (errno == ENOENT)

diff --git a/sysdeps/unix/sysv/linux/fexecve.c b/sysdeps/unix/sysv/linux/fexecve.c
index f37c245..df25c2a 100644 (file)
--- a/sysdeps/unix/sysv/linux/fexecve.c
+++ b/sysdeps/unix/sysv/linux/fexecve.c
@@ -22,6 +22,7 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 
+#include <fd_to_filename.h>
 #include <sysdep.h>
 #include <sys/syscall.h>
 #include <kernel-features.h>
@@ -49,12 +50,9 @@ fexecve (int fd, char *const argv[], char *const envp[])
 
 #ifndef __ASSUME_EXECVEAT
   /* We use the /proc filesystem to get the information.  If it is not
-     mounted we fail.  */
-  char buf[sizeof "/proc/self/fd/" + sizeof (int) * 3];
-  __snprintf (buf, sizeof (buf), "/proc/self/fd/%d", fd);
-
-  /* We do not need the return value.  */
-  __execve (buf, argv, envp);
+     mounted we fail.  We do not need the return value.  */
+  struct fd_to_filename filename;
+  __execve (__fd_to_filename (fd, &filename), argv, envp);
 
   int save = errno;