[v5,04/12] tests: fix warn unused result on asprintf calls

When enabling _FORTIFY_SOURCE, some functions now lead to warnings when
their result is not checked.
---
Changes since v4:
 - Properly use xasprintf in all cases in posix/tst-execlp2.c

 argp/argp-test.c           |  8 +++++---
 posix/tst-execl2.c         |  8 ++------
 posix/tst-execle2.c        |  8 ++------
 posix/tst-execlp2.c        | 10 +++-------
 posix/tst-execv2.c         |  8 ++------
 posix/tst-execve2.c        |  8 ++------
 posix/tst-execvp2.c        | 17 ++++-------------
 stdio-common/bug5.c        |  4 +++-
 stdio-common/test-fwrite.c |  4 +++-
 stdio-common/tst-fseek.c   |  5 ++---
 10 files changed, 28 insertions(+), 52 deletions(-)

On 2023-06-01 10:27, Frédéric Bérat wrote:
> When enabling _FORTIFY_SOURCE, some functions now lead to warnings when
> their result is not checked.
> ---
> Changes since v4:
>   - Properly use xasprintf in all cases in posix/tst-execlp2.c
> 
>   argp/argp-test.c           |  8 +++++---
>   posix/tst-execl2.c         |  8 ++------
>   posix/tst-execle2.c        |  8 ++------
>   posix/tst-execlp2.c        | 10 +++-------
>   posix/tst-execv2.c         |  8 ++------
>   posix/tst-execve2.c        |  8 ++------
>   posix/tst-execvp2.c        | 17 ++++-------------
>   stdio-common/bug5.c        |  4 +++-
>   stdio-common/test-fwrite.c |  4 +++-
>   stdio-common/tst-fseek.c   |  5 ++---
>   10 files changed, 28 insertions(+), 52 deletions(-)
> 
> diff --git a/argp/argp-test.c b/argp/argp-test.c
> index c7e20f6235..cd69c81b1a 100644
> --- a/argp/argp-test.c
> +++ b/argp/argp-test.c
> @@ -25,6 +25,8 @@
>   #include <string.h>
>   #include <argp.h>
>   
> +#include <support/support.h>
> +
>   const char *argp_program_version = "argp-test 1.0";
>   
>   struct argp_option sub_options[] =
> @@ -178,12 +180,12 @@ help_filter (int key, const char *text, void *input)
>     if (key == ARGP_KEY_HELP_POST_DOC && text)
>       {
>         time_t now = time (0);
> -      asprintf (&new_text, text, ctime (&now));
> +      new_text = xasprintf (text, ctime (&now));
>       }
>     else if (key == 'f')
>       /* Show the default for the --foonly option.  */
> -    asprintf (&new_text, "%s (ZOT defaults to %x)",
> -	      text, params->foonly_default);
> +    new_text = xasprintf ("%s (ZOT defaults to %x)",
> +		          text, params->foonly_default);
>     else
>       new_text = (char *)text;
>   
> diff --git a/posix/tst-execl2.c b/posix/tst-execl2.c
> index 5b74959ef8..d2f4453ad8 100644
> --- a/posix/tst-execl2.c
> +++ b/posix/tst-execl2.c
> @@ -18,12 +18,8 @@ prepare (int argc, char *argv[])
>   {
>     char *buf;
>     int off;
> -  asprintf (&buf, "cp %s %n%s-copy", argv[0], &off, argv[0]);
> -  if (buf == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      exit (1);
> -    }
> +
> +  buf = xasprintf ("cp %s %n%s-copy", argv[0], &off, argv[0]);
>     if (system (buf) != 0)
>       {
>         puts ("system  failed");
> diff --git a/posix/tst-execle2.c b/posix/tst-execle2.c
> index 0430b7b573..8e3ad9acb6 100644
> --- a/posix/tst-execle2.c
> +++ b/posix/tst-execle2.c
> @@ -18,12 +18,8 @@ prepare (int argc, char *argv[])
>   {
>     char *buf;
>     int off;
> -  asprintf (&buf, "cp %s %n%s-copy", argv[0], &off, argv[0]);
> -  if (buf == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      exit (1);
> -    }
> +
> +  buf = xasprintf ("cp %s %n%s-copy", argv[0], &off, argv[0]);
>     if (system (buf) != 0)
>       {
>         puts ("system  failed");
> diff --git a/posix/tst-execlp2.c b/posix/tst-execlp2.c
> index 81a723dda4..b42037babd 100644
> --- a/posix/tst-execlp2.c
> +++ b/posix/tst-execlp2.c
> @@ -22,12 +22,8 @@ prepare (int argc, char *argv[])
>   {
>     char *buf;
>     int off;
> -  asprintf (&buf, "cp %s %n%s-copy", argv[0], &off, argv[0]);
> -  if (buf == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      exit (1);
> -    }
> +
> +  buf = xasprintf ("cp %s %n%s-copy", argv[0], &off, argv[0]);
>     if (system (buf) != 0)
>       {
>         puts ("system  failed");
> @@ -59,7 +55,7 @@ do_test (void)
>         return 1;
>       }
>     char *path;
> -  asprintf (&path, "%s:../libio:../elf", bindir);
> +  path = xasprintf ("%s:../libio:../elf", bindir);
>     if (path == NULL)

You don't need this check anymore, do you?

>       {
>         puts ("asprintf  failed");
> diff --git a/posix/tst-execv2.c b/posix/tst-execv2.c
> index a5168a269c..5fd6c46c1f 100644
> --- a/posix/tst-execv2.c
> +++ b/posix/tst-execv2.c
> @@ -18,12 +18,8 @@ prepare (int argc, char *argv[])
>   {
>     char *buf;
>     int off;
> -  asprintf (&buf, "cp %s %n%s-copy", argv[0], &off, argv[0]);
> -  if (buf == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      exit (1);
> -    }
> +
> +  buf = xasprintf ("cp %s %n%s-copy", argv[0], &off, argv[0]);
>     if (system (buf) != 0)
>       {
>         puts ("system  failed");
> diff --git a/posix/tst-execve2.c b/posix/tst-execve2.c
> index 1a804e94fd..e0a7c84346 100644
> --- a/posix/tst-execve2.c
> +++ b/posix/tst-execve2.c
> @@ -18,12 +18,8 @@ prepare (int argc, char *argv[])
>   {
>     char *buf;
>     int off;
> -  asprintf (&buf, "cp %s %n%s-copy", argv[0], &off, argv[0]);
> -  if (buf == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      exit (1);
> -    }
> +
> +  buf = xasprintf ("cp %s %n%s-copy", argv[0], &off, argv[0]);
>     if (system (buf) != 0)
>       {
>         puts ("system  failed");
> diff --git a/posix/tst-execvp2.c b/posix/tst-execvp2.c
> index 440dfab438..f6c0cb4d98 100644
> --- a/posix/tst-execvp2.c
> +++ b/posix/tst-execvp2.c
> @@ -25,12 +25,8 @@ prepare (int argc, char *argv[])
>   {
>     char *buf;
>     int off;
> -  asprintf (&buf, "cp %s %n%s-copy", argv[0], &off, argv[0]);
> -  if (buf == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      exit (1);
> -    }
> +
> +  buf = xasprintf ("cp %s %n%s-copy", argv[0], &off, argv[0]);
>     if (system (buf) != 0)
>       {
>         puts ("system  failed");
> @@ -61,13 +57,8 @@ do_test (void)
>         puts ("canonicalize_file_name failed");
>         return 1;
>       }
> -  char *path;
> -  asprintf (&path, "%s:../libio:../elf", bindir);
> -  if (path == NULL)
> -    {
> -      puts ("asprintf  failed");
> -      return 1;
> -    }
> +
> +  char *path = xasprintf ("%s:../libio:../elf", bindir);
>   
>     setenv ("PATH", path, 1);
>   
> diff --git a/stdio-common/bug5.c b/stdio-common/bug5.c
> index 7bfe9b2b8d..dfa19aed55 100644
> --- a/stdio-common/bug5.c
> +++ b/stdio-common/bug5.c
> @@ -7,6 +7,8 @@
>   #include <stdlib.h>
>   #include <unistd.h>
>   
> +#include <support/support.h>
> +
>   static char buf[8192];
>   
>   int
> @@ -60,7 +62,7 @@ main (void)
>        the perhaps incompatible new shared libraries.  */
>     unsetenv ("LD_LIBRARY_PATH");
>   
> -  asprintf (&printbuf, "cmp %s %s", inname, outname);
> +  printbuf = xasprintf ("cmp %s %s", inname, outname);
>     result = system (printbuf);

Btw, given the number of times this pattern is repeating, I wonder if 
there's utility in wrapping this xasprintf + system pattern.  Anyway, 
it's for a different patch if you or anybody else ever feels motivated 
to do this cleanup.

>     remove (inname);
>     remove (outname);
> diff --git a/stdio-common/test-fwrite.c b/stdio-common/test-fwrite.c
> index 5677c6da80..7f383921ca 100644
> --- a/stdio-common/test-fwrite.c
> +++ b/stdio-common/test-fwrite.c
> @@ -1,6 +1,8 @@
>   #include <stdio.h>
>   #include <string.h>
>   
> +#include <support/support.h>
> +
>   static int
>   do_test (void)
>   {
> @@ -57,7 +59,7 @@ do_test (void)
>         return 1;
>       }
>   
> -  asprintf (&line, "\
> +  line = xasprintf ("\
>   GDB is free software and you are welcome to distribute copies of it\n\
>    under certain conditions; type \"show copying\" to see the conditions.\n\
>   There is absolutely no warranty for GDB; type \"show warranty\" for details.\n\
> diff --git a/stdio-common/tst-fseek.c b/stdio-common/tst-fseek.c
> index c4ac17cdf4..386dd1dd51 100644
> --- a/stdio-common/tst-fseek.c
> +++ b/stdio-common/tst-fseek.c
> @@ -25,6 +25,7 @@
>   #include <time.h>
>   #include <sys/stat.h>
>   
> +#include <support/support.h>
>   
>   static int
>   do_test (void)
> @@ -44,9 +45,7 @@ do_test (void)
>     if (tmpdir == NULL || tmpdir[0] == '\0')
>       tmpdir = "/tmp";
>   
> -  asprintf (&fname, "%s/tst-fseek.XXXXXX", tmpdir);
> -  if (fname == NULL)
> -    error (EXIT_FAILURE, errno, "cannot generate name for temporary file");
> +  fname = xasprintf ("%s/tst-fseek.XXXXXX", tmpdir);
>   
>     /* Create a temporary file.   */
>     fd = mkstemp (fname);