[PATCH] posix: Ignore non opened files on tst-spawn5

[PATCH] posix: Ignore non opened files on tst-spawn5

[Adhemerval Zanella]

The make program  might open a pipe for its job server, which triggers
an invalid check on the spawned process.  This patch now passes the
lowest file descriptor as ithe first argument, so only the range
that was actually opened is checked.

Checked on x86_64-linux-gnu and i686-linux-gnu and centos7 (which
triggers the issue).
---
 posix/tst-spawn5.c | 55 +++++++++++++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 20 deletions(-)

diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c
index 88d8c94c78..ffa3219c76 100644
--- a/posix/tst-spawn5.c
+++ b/posix/tst-spawn5.c
@@ -39,7 +39,7 @@ static int restart;
 
 /* Hold the four initial argument used to respawn the process, plus
    the extra '--direct' and '--restart', and a final NULL.  */
-static char *initial_argv[7];
+static char *initial_argv[8];
 static int initial_argv_count;
 
 #define CMDLINE_OPTIONS \
@@ -58,11 +58,24 @@ open_multiple_temp_files (void)
   return lowfd;
 }
 
+static int
+parse_fd (const char *str)
+{
+  char *endptr;
+  long unsigned int fd = strtoul (str, &endptr, 10);
+  if (*endptr != '\0' || fd > INT_MAX)
+    FAIL_EXIT1 ("invalid file descriptor value: %s", str);
+  return fd;
+}
+
 /* Called on process re-execution.  The arguments are the expected opened
    file descriptors.  */
 _Noreturn static void
 handle_restart (int argc, char *argv[])
 {
+  TEST_VERIFY (argc > 0);
+  int lowfd = parse_fd (argv[0]);
+
   size_t nfds = argc > 1 ? argc - 1 : 0;
   struct fd_t
   {
@@ -71,12 +84,7 @@ handle_restart (int argc, char *argv[])
   } *fds = xmalloc (sizeof (struct fd_t) * nfds);
   for (int i = 0; i < nfds; i++)
     {
-      char *endptr;
-      long unsigned int fd = strtoul (argv[i+1], &endptr, 10);
-      if (*endptr != '\0' || fd > INT_MAX)
-	FAIL_EXIT1 ("argv[%d]: invalid file descriptor value: %s", i, argv[i]);
-
-      fds[i].fd = fd;
+      fds[i].fd = parse_fd (argv[i + 1]);
       fds[i].found = false;
     }
 
@@ -104,12 +112,9 @@ handle_restart (int argc, char *argv[])
         FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s",
                     e->d_name);
 
-      /* Skip the descriptor which is used to enumerate the descriptors.  */
-      if (fd == dirfd (dirp)
-          || fd == STDIN_FILENO
-	  || fd == STDOUT_FILENO
-	  || fd == STDERR_FILENO)
-        continue;
+      /* Ignore the descriptors not in the range of the opened files.  */
+      if (fd < lowfd || fd == dirfd (dirp))
+	continue;
 
       bool found = false;
       for (int i = 0; i < nfds; i++)
@@ -117,7 +122,11 @@ handle_restart (int argc, char *argv[])
 	  fds[i].found = found = true;
 
       if (!found)
-        FAIL_EXIT1 ("unexpected open file descriptor: %ld", fd);
+	{
+	  char *path = xasprintf ("/proc/self/fd/%s", e->d_name);
+	  char *resolved = xreadlink (path);
+	  FAIL_EXIT1 ("unexpected open file descriptor %ld: %s", fd, resolved);
+	}
     }
   closedir (dirp);
 
@@ -134,15 +143,17 @@ static void
 spawn_closefrom_test (posix_spawn_file_actions_t *fa, int lowfd, int highfd,
 		      int *extrafds, size_t nextrafds)
 {
-  /* 3 or 6 elements from initial_argv:
+  /* 3 or 7 elements from initial_argv:
        + path to ld.so          optional
        + --library-path         optional
        + the library path       optional
        + application name
        + --direct
        + --restart
-     up to 2 * maximum_fd arguments (the expected open file descriptors),
-     plus NULL.  */
+       + lowest opened file descriptor
+       + up to 2 * maximum_fd arguments (the expected open file descriptors),
+	 plus NULL.  */
+
   int argv_size = initial_argv_count + 2 * NFDS + 1;
   char *args[argv_size];
   int argc = 0;
@@ -150,6 +161,8 @@ spawn_closefrom_test (posix_spawn_file_actions_t *fa, int lowfd, int highfd,
   for (char **arg = initial_argv; *arg != NULL; arg++)
     args[argc++] = *arg;
 
+  args[argc++] = xasprintf ("%d", lowfd);
+
   for (int i = lowfd; i < highfd; i++)
     args[argc++] = xasprintf ("%d", i);
 
@@ -265,14 +278,16 @@ do_test (int argc, char *argv[])
 
      - six parameters left if called through re-execution:
        + argv[1]: the application name
-       + argv[2]: first expected open file descriptor
-       + argv[n]: last expected open file descritptor
+       + argv[2]: the lowest file descriptor expected
+       + argv[3]: first expected open file descriptor   optional
+       + argv[n]: last expected open file descritptor   optional
 
      * When built with --enable-hardcoded-path-in-tests or issued without
        using the loader directly.  */
 
   if (restart)
-    handle_restart (argc, argv);
+    /* Ignore the application name. */
+    handle_restart (argc - 1, &argv[1]);
 
   TEST_VERIFY_EXIT (argc == 2 || argc == 5);
 
-- 
2.30.2

Re: [PATCH] posix: Ignore non opened files on tst-spawn5

[Andreas Schwab]

On Jul 13 2021, Adhemerval Zanella via Libc-alpha wrote:

> diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c
> index 88d8c94c78..ffa3219c76 100644
> --- a/posix/tst-spawn5.c
> +++ b/posix/tst-spawn5.c
> @@ -39,7 +39,7 @@ static int restart;
>  
>  /* Hold the four initial argument used to respawn the process, plus
>     the extra '--direct' and '--restart', and a final NULL.  */
> -static char *initial_argv[7];
> +static char *initial_argv[8];

Why is that needed?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: [PATCH] posix: Ignore non opened files on tst-spawn5

[Florian Weimer]

* Adhemerval Zanella via Libc-alpha:

> The make program  might open a pipe for its job server, which triggers
> an invalid check on the spawned process.  This patch now passes the
> lowest file descriptor as ithe first argument, so only the range
> that was actually opened is checked.
>
> Checked on x86_64-linux-gnu and i686-linux-gnu and centos7 (which
> triggers the issue).

It fixes the test failures on my systems, thanks.

Florian

Re: [PATCH] posix: Ignore non opened files on tst-spawn5

[Adhemerval Zanella]

On 13/07/2021 11:57, Andreas Schwab wrote:
> On Jul 13 2021, Adhemerval Zanella via Libc-alpha wrote:
> 
>> diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c
>> index 88d8c94c78..ffa3219c76 100644
>> --- a/posix/tst-spawn5.c
>> +++ b/posix/tst-spawn5.c
>> @@ -39,7 +39,7 @@ static int restart;
>>  
>>  /* Hold the four initial argument used to respawn the process, plus
>>     the extra '--direct' and '--restart', and a final NULL.  */
>> -static char *initial_argv[7];
>> +static char *initial_argv[8];
> 
> Why is that needed?

It is not, I added because I started the patch in a way it was required.
I will remove it.