On 11 March 2013 17:19, Andreas Schwab <sch...@suse.de> wrote:
> Some applications like to test /proc/$$/exe (where $$ is the own pid) to
> find out who they are. Handle it like /proc/self/exe.
>
> Also, do the same handling in readlinkat.
Sorry I didn't get round to reviewing this earlier; I think
it slipped through the cracks :-(
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 19630ea..3e5a6ae 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6413,7 +6413,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
> arg1,
> if (!p || !p2)
> ret = -TARGET_EFAULT;
> else {
> - if (strncmp((const char *)p, "/proc/self/exe", 14) == 0) {
> + char myself[PATH_MAX];
> + snprintf(myself, sizeof(myself), "/proc/%d/exe", getpid());
> + if (strncmp((const char *)p, "/proc/self/exe", 14) == 0 ||
> + strcmp((const char *)p, myself) == 0) {
> char real[PATH_MAX];
> temp = realpath(exec_path,real);
> ret = (temp==NULL) ? get_errno(-1) : strlen(real) ;
> @@ -6429,13 +6432,24 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
> arg1,
> #if defined(TARGET_NR_readlinkat) && defined(__NR_readlinkat)
> case TARGET_NR_readlinkat:
> {
> - void *p2;
> + void *p2, *temp;
> p = lock_user_string(arg2);
> p2 = lock_user(VERIFY_WRITE, arg3, arg4, 0);
> if (!p || !p2)
> ret = -TARGET_EFAULT;
> - else
> - ret = get_errno(sys_readlinkat(arg1, path(p), p2, arg4));
You could add braces on the 'then' part of this if() and get rid
of the stray hardcoded tab in the existing code. (not a requirement
but since we're in the area anyway...)
> + else {
> + char myself[PATH_MAX];
> + snprintf(myself, sizeof(myself), "/proc/%d/exe", getpid());
> + if (strncmp((const char *)p, "/proc/self/exe", 14) == 0 ||
> + strcmp((const char *)p, myself) == 0) {
> + char real[PATH_MAX];
> + temp = realpath(exec_path,real);
> + ret = (temp==NULL) ? get_errno(-1) : strlen(real) ;
> + snprintf((char *)p2, arg3, "%s", real);
This seems to be a fair chunk of code in common with the readlink
case above -- can we abstract it out? (ideally to a function
somewhere in the same area of this file as the code that handles
intercepting /proc/ calls for open().)
It would be consistent to support /proc/$$/ for all the open()
intercepts too.
> + }
> + else
> + ret = get_errno(sys_readlinkat(arg1, path(p), p2, arg4));
> + }
> unlock_user(p2, arg3, ret);
> unlock_user(p, arg2, 0);
> }
> --
> 1.8.1.5
thanks
-- PMM
