[libvirt] [PATCH] Ensure binary is resolved wrt $PATH in virExec

[Eric Blake]

On 03/15/2011 11:14 AM, Daniel P. Berrange wrote:
> virExec would only resolved the binary to $PATH if no env
> variables were being set. Since there is no execvep() API
> in POSIX, we use virFindFileInPath to manually resolve
> the binary and then use execv() instead of execvp().

It might be worth a gnulib module for execvpe (of course, such a module
would fail with ENOSYS on mingw, so we'd still have to have a
WIN32-specific fallback for virExec).  But that can be another day.

> +++ b/src/util/util.c
> @@ -475,6 +475,18 @@ __virExec(const char *const*argv,
>      int childout = -1;
>      int childerr = -1;
>      int tmpfd;
> +    const char *binary = NULL;
> +
> +    if (argv[0][0] != '/') {
> +        if (!(binary = virFindFileInPath(argv[0]))) {
> +            virReportSystemError(ENOENT,
> +                                 _("Cannot find '%s' in path"),
> +                                 argv[0]);
> +            return -1;
> +        }
> +    } else {
> +        binary = argv[0];
> +    }
>  
>      if ((null = open("/dev/null", O_RDWR)) < 0) {
>          virReportSystemError(errno,
> @@ -694,9 +706,9 @@ __virExec(const char *const*argv,
>      virLogReset();
>  
>      if (envp)
> -        execve(argv[0], (char **) argv, (char**)envp);
> +        execve(binary, (char **) argv, (char**)envp);
>      else
> -        execvp(argv[0], (char **) argv);
> +        execv(binary, (char **) argv);
>  
>      virReportSystemError(errno,
>                           _("cannot execute binary %s"),

Memory leak in the parent, and in the child on failure to exec.  (The
child leak is less important - it's about to _exit anyways).  You need
this in at least the parent some point after the fork:

if (binary != argv[0])
    VIR_FREE(binary);


ACK with that nit fixed.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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