[DTrace-devel] [PATCH 2/2] link: no longer add utsname in USDT ELF notes

[Kris Van Hees]

USDT ELF notes used to contain utsname information for debugging, but
this has proven to be troublesome for distributions that expect to be
able to regenerate build objects with identical data.  Since the
utsname data contains the system name, the USDT ELF notes were causing
comparisons between generates and regenerated objects to fail.

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 libdtrace/dt_link.c | 48 ---------------------------------------------
 1 file changed, 48 deletions(-)

diff --git a/libdtrace/dt_link.c b/libdtrace/dt_link.c
index aa5eb735..d8188881 100644
--- a/libdtrace/dt_link.c
+++ b/libdtrace/dt_link.c
@@ -261,52 +261,6 @@ note_add_version(usdt_elf_t *usdt)
 	return 0;
 }
 
-static int
-note_add_utsname(usdt_elf_t *usdt)
-{
-	Elf_Data	*dbuf;
-	char		*buf, *p;
-	size_t		len, sz;
-
-#define UTSN_NOTE_HEADSZ \
-		((3 * sizeof(uint32_t)) +	/* namesz, descsz, type */ \
-		 ALIGN(5, 4))			/* "utsn\0" */
-
-	/* Ensure the note starts on a 4-byte alignment boundary. */
-	usdt->base = ALIGN(usdt->base + usdt->size, 4);
-	usdt->size = 0;
-
-	len = sizeof(struct utsname);
-	sz = UTSN_NOTE_HEADSZ + ALIGN(len, 4);
-
-	buf = malloc(sz);
-	if (buf == NULL)
-		return dt_set_errno(usdt->dtp, EDT_NOMEM);
-	memset(buf, 0, sz);
-
-	/* Construct the note header. */
-	*((uint32_t *)&buf[0]) = 5;
-	*((uint32_t *)&buf[4]) = sz - UTSN_NOTE_HEADSZ;
-	*((uint32_t *)&buf[8]) = 1;
-	memcpy(&buf[12], "utsn", 4);
-
-	/* Add the data. */
-	p = buf + UTSN_NOTE_HEADSZ;
-	memcpy(p, &usdt->dtp->dt_uts, sizeof(struct utsname));
-
-	/* Add the note header. */
-	dbuf = elf_newdata(usdt->note);
-	dbuf->d_align = sizeof(uint32_t);
-	dbuf->d_off = usdt->base;
-	dbuf->d_buf = buf;
-	dbuf->d_size = sz;
-	usdt->size = sz;
-
-	usdt->notes.next = NULL;
-
-	return 0;
-}
-
 static int
 create_elf64(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, int fd, uint_t flags)
 {
@@ -398,8 +352,6 @@ create_elf64(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, int fd, uint_t flags)
 	if (!(flags & DTRACE_D_STRIP)) {
 		if (note_add_version(usdt) == -1)
 			goto fail;
-		if (note_add_utsname(usdt) == -1)
-			goto fail;
 	}
 
 	dt_free(dtp, usdt);
-- 
2.52.0