Re: [PATCH v2] linux-user/syscall: Implement execve without execveat

[Pierrick Bouvier]

On 7/5/23 12:26, Michael Tokarev wrote:

05.07.2023 12:00, Pierrick Bouvier wrote:
...

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 08162cc966..4945ddd7f2 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -659,6 +659,7 @@ safe_syscall4(pid_t, wait4, pid_t, pid, int *, status, int, 
options, \
   #endif
   safe_syscall5(int, waitid, idtype_t, idtype, id_t, id, siginfo_t *, infop, \
                 int, options, struct rusage *, rusage)
+safe_syscall3(int, execve, const char *, filename, char **, argv, char **, 
envp)
   safe_syscall5(int, execveat, int, dirfd, const char *, filename,
                 char **, argv, char **, envp, int, flags)
   #if defined(TARGET_NR_select) || defined(TARGET_NR__newselect) || \
@@ -8615,9 +8616,9 @@ ssize_t do_guest_readlink(const char *pathname, char 
*buf, size_t bufsiz)
       return ret;
   }

-static int do_execveat(CPUArchState *cpu_env, int dirfd,

-                       abi_long pathname, abi_long guest_argp,
-                       abi_long guest_envp, int flags)
+static int do_execv(CPUArchState *cpu_env, int dirfd,
+                    abi_long pathname, abi_long guest_argp,
+                    abi_long guest_envp, int flags, bool is_execveat)
   {
       int ret;
       char **argp, **envp;
@@ -8696,11 +8697,14 @@ static int do_execveat(CPUArchState *cpu_env, int dirfd,
           goto execve_efault;
       }

+ const char* exe = p;

       if (is_proc_myself(p, "exe")) {
-        ret = get_errno(safe_execveat(dirfd, exec_path, argp, envp, flags));
-    } else {
-        ret = get_errno(safe_execveat(dirfd, p, argp, envp, flags));
+        exe = exec_path;
       }
+    ret = is_execveat ?
+        safe_execveat(dirfd, exe, argp, envp, flags):
+        safe_execve(exe, argp, envp);
+    ret = get_errno(ret);

This one has 2 issues reported by checkpatch.pl:

$ git show | ./scripts/checkpatch.pl -

ERROR: "foo* bar" should be "foo *bar"
#161: FILE: linux-user/syscall.c:8700:
+    const char* exe = p;

ERROR: spaces required around that ':' (ctx:VxE)
#169: FILE: linux-user/syscall.c:8705:
+        safe_execveat(dirfd, exe, argp, envp, flags):
                                                       ^

total: 2 errors, 0 warnings, 47 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

As I mentioned in the v1, I don't remember offhand how the arithmetic if
should be styled in qemu.  At the very best, the v2 variant is difficult
to read because ":" is too close to ";" visually, an extra space before
it will make it more explicit.

Sorry about it.
I'll fix it, and use style advised by Philippe.

Other than that, I'm fine with this version.

With the checkpatch issues fixed,

Reviewed-by: Michael Tokarev <m...@tls.msk.ru>

Thanks,

/mjt