Re: procfs files vs symlink

[RVP <rvp%SDF.ORG@localhost>]

On Fri, 14 Jan 2022, Robert Elz wrote:

> If your patch makes any difference to the way ls /proc/self/fd
> works, that is just a fluke (relates to the way ls happens to
> sequence its operations) and in no way any kind of general fix.

It does not, and wasn't meant to. I noticed that d_type was being
set to VREG and attached a patch for that to my reply.

> If procfs is not setting d_type correctly, that should be fixed.

I think this does it:

---START---
--- sys/miscfs/procfs/procfs_vnops.c.orig	2022-01-12 03:57:25.944841288 +0000
+++ sys/miscfs/procfs/procfs_vnops.c	2022-01-14 06:12:33.154215255 +0000
@@ -162,12 +162,12 @@
 	{ DT_DIR, N("fd"),	PFSfd,		NULL },
 	{ DT_DIR, N("task"),	PFStask,	procfs_validfile_linux },
 	{ DT_LNK, N("cwd"),	PFScwd,		NULL },
-	{ DT_LNK, N("emul"),	PFSemul,	NULL },
+	{ DT_REG, N("emul"),	PFSemul,	NULL },
 	{ DT_LNK, N("root"),	PFSchroot,	NULL },
 	{ DT_REG, N("auxv"),	PFSauxv,	procfs_validauxv },
 	{ DT_REG, N("cmdline"), PFScmdline,	NULL },
 	{ DT_REG, N("environ"), PFSenviron,	NULL },
-	{ DT_REG, N("exe"),	PFSexe,		procfs_validfile },
+	{ DT_LNK, N("exe"),	PFSexe,		procfs_validfile },
 	{ DT_REG, N("file"),	PFSfile,	procfs_validfile },
 	{ DT_REG, N("fpregs"),	PFSfpregs,	procfs_validfpregs },
 	{ DT_REG, N("limit"),	PFSlimit,	NULL },
@@ -223,6 +223,7 @@
 int	procfs_pathconf(void *);
 int	procfs_getpages(void *);

+static uint8_t fttodt(file_t *fp);
 static int atoi(const char *, size_t);

 /*
@@ -1410,7 +1411,7 @@
 			d.d_fileno = PROCFS_FILENO(pfs->pfs_pid, PFSfd, i - 2);
 			d.d_namlen = snprintf(d.d_name, sizeof(d.d_name),
 			    "%lld", (long long)(i - 2));
-			d.d_type = VREG;
+			d.d_type = fttodt(fp);
 			if ((error = uiomove(&d, UIO_MX, uio)) != 0)
 				break;
 			if (cookies)
@@ -1731,6 +1732,34 @@
 	return (EFAULT);
 }

+/**
+ * convert DTYPE_XXX to corresponding DT_XXX
+ * matching what procfs_loadvnode() does.
+ */
+static uint8_t
+fttodt(file_t *fp)
+{
+	switch (fp->f_type) {
+	case DTYPE_VNODE:
+		switch (fp->f_vnode->v_type) {
+		case VREG:	return DT_REG;
+		case VDIR:	return DT_LNK;	/* symlink */
+		case VBLK:	return DT_BLK;
+		case VCHR:	return DT_CHR;
+		case VLNK:	return DT_LNK;
+		case VSOCK:	return DT_SOCK;
+		case VFIFO:	return DT_FIFO;
+		default:	return DT_UNKNOWN;
+		}
+	case DTYPE_PIPE:	return DT_FIFO;
+	case DTYPE_SOCKET:	return DT_SOCK;
+	case DTYPE_KQUEUE:	/*FALLTHROUGH*/
+	case DTYPE_MISC:	/*FALLTHROUGH*/
+	case DTYPE_SEM:		return DT_LNK;	/* symlinks */
+	default:		return DT_UNKNOWN;
+	}
+}
+
 /*
  * convert decimal ascii to int
  */
---END---

Thx,
-RVP