13987 libproc could use standard lists

Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Patrick Mooney <pmooney@pfmooney.com>
Approved by: Dan McDonald <danmcd@joyent.com>

23 files changed, 122 insertions, 196 deletions

diff --git a/usr/src/cmd/mdb/Makefile.common b/usr/src/cmd/mdb/Makefile.common
index be0f680194..5616038726 100644
--- a/usr/src/cmd/mdb/Makefile.common
+++ b/usr/src/cmd/mdb/Makefile.common
@@ -34,7 +34,6 @@ COMMON_MODULES_PROC = \
 	dof \
 	libavl \
 	libc \
-	libcmdutils \
 	libfknsmb \
 	libfksmbfs \
 	libfksmbsrv \
@@ -47,6 +46,7 @@ COMMON_MODULES_PROC = \
 	libumem \
 	libuutil \
 	libzpool \
+	list \
 	mdb_ds \
 	mdb_test
 
diff --git a/usr/src/cmd/mdb/common/mdb/mdb_module_load.c b/usr/src/cmd/mdb/common/mdb/mdb_module_load.c
index 141aa3a5cd..37f0109663 100644
--- a/usr/src/cmd/mdb/common/mdb/mdb_module_load.c
+++ b/usr/src/cmd/mdb/common/mdb/mdb_module_load.c
@@ -23,6 +23,7 @@
  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012 by Delphix. All rights reserved.
  * Copyright 2019 Joyent, Inc.
+ * Copyright 2021 Oxide Computer Company
  */
 
 #include <sys/param.h>
@@ -182,6 +183,16 @@ module_load(void *fp, const mdb_map_t *map, const char *fullname)
 		return (module_load(fp, map, "libc.so.1"));
 	}
 
+	if (strstr(fullname, "ld.so") != NULL) {
+		/*
+		 * This is even more of a kludge. But if we find something has
+		 * basically tried to load ld, we will always implicitly load
+		 * the list dmod because several binaries and libraries just
+		 * build it as a .o and include it in their ELF object.
+		 */
+		(void) mdb_module_load("list", mld->mld_mode);
+	}
+
 	return (0);
 }
 
diff --git a/usr/src/cmd/mdb/common/modules/libproc/libproc.c b/usr/src/cmd/mdb/common/modules/libproc/libproc.c
index 09530ea322..5ec551d5b1 100644
--- a/usr/src/cmd/mdb/common/modules/libproc/libproc.c
+++ b/usr/src/cmd/mdb/common/modules/libproc/libproc.c
@@ -22,6 +22,9 @@
  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
+/*
+ * Copyright 2021 Oxide Computer Company
+ */
 
 #include <libproc.h>
 #include <Pcontrol.h>
@@ -221,64 +224,28 @@ pr_addr2map(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
  *
  * Given a ps_prochandle_t, walk all its file_info_t structures.
  */
-typedef struct {
-	uintptr_t	fiw_next;
-	int		fiw_count;
-} file_info_walk_t;
-
 static int
 pr_file_info_walk_init(mdb_walk_state_t *wsp)
 {
-	ps_prochandle_t psp;
-	file_info_walk_t *fiw;
-
 	if (wsp->walk_addr == 0) {
 		mdb_warn("pr_file_info doesn't support global walks\n");
 		return (WALK_ERR);
 	}
 
-	if (mdb_vread(&psp, sizeof (ps_prochandle_t), wsp->walk_addr) == -1) {
-		mdb_warn("failed to read ps_prochandle at %p", wsp->walk_addr);
+	wsp->walk_addr += offsetof(ps_prochandle_t, file_head);
+	if (mdb_layered_walk("list", wsp) == -1) {
+		mdb_warn("failed to walk layered 'list'");
 		return (WALK_ERR);
 	}
 
-	fiw = mdb_alloc(sizeof (file_info_walk_t), UM_SLEEP);
-
-	fiw->fiw_next = (uintptr_t)psp.file_head.list_forw;
-	fiw->fiw_count = psp.num_files;
-	wsp->walk_data = fiw;
-
 	return (WALK_NEXT);
 }
 
 static int
 pr_file_info_walk_step(mdb_walk_state_t *wsp)
 {
-	file_info_walk_t *fiw = wsp->walk_data;
-	file_info_t f;
-	int status;
-
-	if (fiw->fiw_count == 0)
-		return (WALK_DONE);
-
-	if (mdb_vread(&f, sizeof (file_info_t), fiw->fiw_next) == -1) {
-		mdb_warn("failed to read file_info_t at %p", fiw->fiw_next);
-		return (WALK_ERR);
-	}
-
-	status = wsp->walk_callback(fiw->fiw_next, &f, wsp->walk_cbdata);
-
-	fiw->fiw_next = (uintptr_t)f.file_list.list_forw;
-	fiw->fiw_count--;
-
-	return (status);
-}
-
-static void
-pr_file_info_walk_fini(mdb_walk_state_t *wsp)
-{
-	file_info_walk_t *fiw = wsp->walk_data;
-	mdb_free(fiw, sizeof (file_info_walk_t));
+	return (wsp->walk_callback(wsp->walk_addr, wsp->walk_layer,
+	    wsp->walk_cbdata));
 }
 
 /*
@@ -358,8 +325,7 @@ static const mdb_dcmd_t dcmds[] = {
 
 static const mdb_walker_t walkers[] = {
 	{ "pr_file_info", "given a ps_prochandle, walk its file_info "
-	    "structures", pr_file_info_walk_init, pr_file_info_walk_step,
-	    pr_file_info_walk_fini },
+	    "structures", pr_file_info_walk_init, pr_file_info_walk_step },
 	{ "pr_map_info", "given a ps_prochandle, walk its map_info structures",
 	    pr_map_info_walk_init, pr_map_info_walk_step,
 	    pr_map_info_walk_fini },
diff --git a/usr/src/cmd/mdb/common/modules/libcmdutils/libcmdutils.c b/usr/src/cmd/mdb/common/modules/list/listmod.c
index bff3f1b733..bff3f1b733 100644
--- a/usr/src/cmd/mdb/common/modules/libcmdutils/libcmdutils.c
+++ b/usr/src/cmd/mdb/common/modules/list/listmod.c
diff --git a/usr/src/cmd/mdb/intel/amd64/libcmdutils/Makefile b/usr/src/cmd/mdb/intel/amd64/list/Makefile
index 8ca2a87ffe..145b59fa91 100644
--- a/usr/src/cmd/mdb/intel/amd64/libcmdutils/Makefile
+++ b/usr/src/cmd/mdb/intel/amd64/list/Makefile
@@ -22,10 +22,10 @@
 # Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 #
 
-MODULE = libcmdutils.so
+MODULE = list.so
 MDBTGT = proc
 
-MODSRCS = libcmdutils.c \
+MODSRCS = listmod.c \
 	  list.c
 
 include ../../../../Makefile.cmd
diff --git a/usr/src/cmd/mdb/intel/ia32/libcmdutils/Makefile b/usr/src/cmd/mdb/intel/ia32/list/Makefile
index de337c3563..d2f6c709ce 100644
--- a/usr/src/cmd/mdb/intel/ia32/libcmdutils/Makefile
+++ b/usr/src/cmd/mdb/intel/ia32/list/Makefile
@@ -22,10 +22,10 @@
 # Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 #
 
-MODULE = libcmdutils.so
+MODULE = list.so
 MDBTGT = proc
 
-MODSRCS = libcmdutils.c \
+MODSRCS = listmod.c \
 	  list.c
 
 include ../../../../Makefile.cmd
diff --git a/usr/src/cmd/mdb/sparc/v7/libcmdutils/Makefile b/usr/src/cmd/mdb/sparc/v7/list/Makefile
index d41231e3e0..88c634f575 100644
--- a/usr/src/cmd/mdb/sparc/v7/libcmdutils/Makefile
+++ b/usr/src/cmd/mdb/sparc/v7/list/Makefile
@@ -22,10 +22,10 @@
 # Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 #
 
-MODULE = libcmdutils.so
+MODULE = list.so
 MDBTGT = proc
 
-MODSRCS = libcmdutils.c \
+MODSRCS = listmod.c \
 	  list.c
 
 include ../../../../Makefile.cmd
diff --git a/usr/src/cmd/mdb/sparc/v9/libcmdutils/Makefile b/usr/src/cmd/mdb/sparc/v9/list/Makefile
index 9e1f58c3bf..db1490f81f 100644
--- a/usr/src/cmd/mdb/sparc/v9/libcmdutils/Makefile
+++ b/usr/src/cmd/mdb/sparc/v9/list/Makefile
@@ -22,10 +22,10 @@
 # Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 #
 
-MODULE = libcmdutils.so
+MODULE = list.so
 MDBTGT = proc
 
-MODSRCS = libcmdutils.c \
+MODSRCS = listmod.c \
 	  list.c
 
 include ../../../../Makefile.cmd
diff --git a/usr/src/lib/libproc/Makefile.com b/usr/src/lib/libproc/Makefile.com
index 9bc99f1b40..b2f7e00e69 100644
--- a/usr/src/lib/libproc/Makefile.com
+++ b/usr/src/lib/libproc/Makefile.com
@@ -30,6 +30,7 @@ LIBRARY = libproc.a
 VERS = .1
 
 CMNOBJS =	\
+	list.o		\
 	P32ton.o	\
 	Pcontrol.o	\
 	Pcore.o		\
@@ -122,6 +123,6 @@ objs/%.o pics/%.o: %.c
 	$(COMPILE.c) -o $@ $<
 	$(POST_PROCESS_O)
 
-objs/%.o pics/%.o: $(SRC)/common/saveargs/%.c
+objs/%.o pics/%.o: $(SRC)/common/list/%.c
 	$(COMPILE.c) -o $@ $<
 	$(POST_PROCESS_O)
diff --git a/usr/src/lib/libproc/common/Pcontrol.c b/usr/src/lib/libproc/common/Pcontrol.c
index d9e3c8b9ea..d6ea26c9ed 100644
--- a/usr/src/lib/libproc/common/Pcontrol.c
+++ b/usr/src/lib/libproc/common/Pcontrol.c
@@ -28,6 +28,7 @@
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright 2015, Joyent, Inc.
  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
+ * Copyright 2021 Oxide Computer Company
  */
 
 #include <assert.h>
@@ -501,6 +502,7 @@ Pxcreate(const char *file,	/* executable file name */
 	P->agentstatfd = -1;
 	Pinit_ops(&P->ops, &P_live_ops);
 	Pinitsym(P);
+	Pinitfd(P);
 
 	/*
 	 * Open the /proc/pid files.
@@ -804,6 +806,7 @@ again:	/* Come back here if we lose it in the Window of Vulnerability */
 	P->agentstatfd = -1;
 	Pinit_ops(&P->ops, &P_live_ops);
 	Pinitsym(P);
+	Pinitfd(P);
 
 	/*
 	 * Open the /proc/pid files
@@ -1182,6 +1185,7 @@ void
 Pfree(struct ps_prochandle *P)
 {
 	uint_t i;
+	fd_info_t *fip;
 
 	if (P->ucaddrs != NULL) {
 		free(P->ucaddrs);
@@ -1199,12 +1203,9 @@ Pfree(struct ps_prochandle *P)
 		free(P->hashtab);
 	}
 
-	while (P->num_fd > 0) {
-		fd_info_t *fip = list_next(&P->fd_head);
-		list_unlink(fip);
+	while ((fip = list_remove_head(&P->fd_head)) != NULL) {
 		proc_fdinfo_free(fip->fd_info);
 		free(fip);
-		P->num_fd--;
 	}
 	(void) mutex_unlock(&P->proc_lock);
 	(void) mutex_destroy(&P->proc_lock);
@@ -1673,7 +1674,7 @@ Prelease(struct ps_prochandle *P, int flags)
 	}
 
 	if (P->state == PS_IDLE) {
-		file_info_t *fptr = list_next(&P->file_head);
+		file_info_t *fptr = list_head(&P->file_head);
 		dprintf("Prelease: releasing handle %p PS_IDLE of file %s\n",
 		    (void *)P, fptr->file_pname);
 		Pfree(P);
@@ -2964,10 +2965,10 @@ Plwp_iter(struct ps_prochandle *P, proc_lwp_f *func, void *cd)
 	 */
 	if (P->state == PS_DEAD) {
 		core_info_t *core = P->data;
-		lwp_info_t *lwp = list_prev(&core->core_lwp_head);
-		uint_t i;
+		lwp_info_t *lwp;
 
-		for (i = 0; i < core->core_nlwp; i++, lwp = list_prev(lwp)) {
+		for (lwp = list_tail(&core->core_lwp_head); lwp != NULL;
+		    lwp = list_prev(&core->core_lwp_head, lwp)) {
 			if (lwp->lwp_psinfo.pr_sname != 'Z' &&
 			    (rv = func(cd, &lwp->lwp_status)) != 0)
 				break;
@@ -3036,10 +3037,10 @@ retry:
 	 */
 	if (P->state == PS_DEAD) {
 		core_info_t *core = P->data;
-		lwp_info_t *lwp = list_prev(&core->core_lwp_head);
-		uint_t i;
+		lwp_info_t *lwp;
 
-		for (i = 0; i < core->core_nlwp; i++, lwp = list_prev(lwp)) {
+		for (lwp = list_tail(&core->core_lwp_head); lwp != NULL;
+		    lwp = list_prev(&core->core_lwp_head, lwp)) {
 			sp = (lwp->lwp_psinfo.pr_sname == 'Z')? NULL :
 			    &lwp->lwp_status;
 			if ((rv = func(cd, sp, &lwp->lwp_psinfo)) != 0)
@@ -3949,6 +3950,7 @@ Pgrab_ops(pid_t pid, void *data, const ps_ops_t *ops, int flags)
 	P->agentctlfd = -1;
 	P->agentstatfd = -1;
 	Pinitsym(P);
+	Pinitfd(P);
 	P->data = data;
 	Pread_status(P);
 
diff --git a/usr/src/lib/libproc/common/Pcontrol.h b/usr/src/lib/libproc/common/Pcontrol.h
index 4aa4091d1f..b5de8ccd50 100644
--- a/usr/src/lib/libproc/common/Pcontrol.h
+++ b/usr/src/lib/libproc/common/Pcontrol.h
@@ -27,6 +27,7 @@
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright 2018 Joyent, Inc.
  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
+ * Copyright 2021 Oxide Computer Company
  */
 
 #ifndef	_PCONTROL_H
@@ -48,6 +49,7 @@
 #include <libproc.h>
 #include <thread.h>
 #include <sys/secflags.h>
+#include <sys/list.h>
 
 #ifdef	__cplusplus
 extern "C" {
@@ -94,7 +96,7 @@ typedef struct sym_tbl {	/* symbol table */
 } sym_tbl_t;
 
 typedef struct file_info {	/* symbol information for a mapped file */
-	plist_t	file_list;	/* linked list */
+	list_node_t file_list;	/* linked list */
 	char	file_pname[PATH_MAX];	/* name from prmap_t */
 	struct map_info *file_map;	/* primary (text) mapping */
 	int	file_ref;	/* references from map_info_t structures */
@@ -136,7 +138,7 @@ typedef struct map_info {	/* description of an address space mapping */
 } map_info_t;
 
 typedef struct lwp_info {	/* per-lwp information from core file */
-	plist_t	lwp_list;	/* linked list */
+	list_node_t lwp_list;	/* linked list */
 	lwpid_t	lwp_id;		/* lwp identifier */
 	lwpsinfo_t lwp_psinfo;	/* /proc/<pid>/lwp/<lwpid>/lwpsinfo data */
 	lwpstatus_t lwp_status;	/* /proc/<pid>/lwp/<lwpid>/lwpstatus data */
@@ -149,7 +151,7 @@ typedef struct lwp_info {	/* per-lwp information from core file */
 } lwp_info_t;
 
 typedef struct fd_info {
-	plist_t	fd_list;	/* linked list */
+	list_node_t fd_list;	/* linked list */
 	prfdinfo_t *fd_info;	/* fd info */
 } fd_info_t;
 
@@ -157,9 +159,8 @@ typedef struct core_info {	/* information specific to core files */
 	char core_dmodel;	/* data model for core file */
 	char core_osabi;	/* ELF OS ABI */
 	int core_errno;		/* error during initialization if != 0 */
-	plist_t core_lwp_head;	/* head of list of lwp info */
+	list_t core_lwp_head;	/* head of list of lwp info */
 	lwp_info_t *core_lwp;	/* current lwp information */
-	uint_t core_nlwp;	/* number of lwp's in list */
 	off64_t core_size;	/* size of core file in bytes */
 	char *core_platform;	/* platform string from core file */
 	struct utsname *core_uts;	/* uname(2) data from core file */
@@ -224,7 +225,7 @@ struct ps_prochandle {
 	size_t	map_count;	/* number of mappings */
 	size_t	map_alloc;	/* number of mappings allocated */
 	uint_t	num_files;	/* number of file elements in file_info */
-	plist_t	file_head;	/* head of mapped files w/ symbol table info */
+	list_t	file_head;	/* head of mapped files w/ symbol table info */
 	char	*execname;	/* name of the executable file */
 	auxv_t	*auxv;		/* the process's aux vector */
 	int	nauxv;		/* number of aux vector entries */
@@ -235,8 +236,7 @@ struct ps_prochandle {
 	uintptr_t *ucaddrs;	/* ucontext-list addresses */
 	uint_t	ucnelems;	/* number of elements in the ucaddrs list */
 	char	*zoneroot;	/* cached path to zone root */
-	plist_t	fd_head;	/* head of file desc info list */
-	int	num_fd;		/* number of file descs in list */
+	list_t	fd_head;	/* head of file desc info list */
 	uintptr_t map_missing;	/* first missing mapping in core due to sig */
 	siginfo_t killinfo;	/* signal that interrupted core dump */
 	psinfo_t spymaster;	/* agent LWP's spymaster, if any */
@@ -274,6 +274,7 @@ extern	int	dupfd(int, int);
 extern	int	set_minfd(void);
 extern	int	Pscantext(struct ps_prochandle *);
 extern	void	Pinitsym(struct ps_prochandle *);
+extern	void	Pinitfd(struct ps_prochandle *);
 extern	void	Preadauxvec(struct ps_prochandle *);
 extern	void	optimize_symtab(sym_tbl_t *);
 extern	void	Pbuild_file_symtab(struct ps_prochandle *, file_info_t *);
diff --git a/usr/src/lib/libproc/common/Pcore.c b/usr/src/lib/libproc/common/Pcore.c
index 39424fad67..ab7b75f807 100644
--- a/usr/src/lib/libproc/common/Pcore.c
+++ b/usr/src/lib/libproc/common/Pcore.c
@@ -28,6 +28,7 @@
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright 2015 Gary Mills
  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
+ * Copyright 2021 Oxide Computer Company
  */
 
 #include <sys/types.h>
@@ -213,11 +214,9 @@ Pfini_core(struct ps_prochandle *P, void *data)
 
 	if (core != NULL) {
 		extern void __priv_free_info(void *);
-		lwp_info_t *nlwp, *lwp = list_next(&core->core_lwp_head);
-		int i;
+		lwp_info_t *lwp;
 
-		for (i = 0; i < core->core_nlwp; i++, lwp = nlwp) {
-			nlwp = list_next(lwp);
+		while ((lwp = list_remove_head(&core->core_lwp_head)) != NULL) {
 #ifdef __sparc
 			if (lwp->lwp_gwins != NULL)
 				free(lwp->lwp_gwins);
@@ -348,11 +347,10 @@ static lwp_info_t *
 lwpid2info(struct ps_prochandle *P, lwpid_t id)
 {
 	core_info_t *core = P->data;
-	lwp_info_t *lwp = list_next(&core->core_lwp_head);
-	lwp_info_t *next;
-	uint_t i;
+	lwp_info_t *lwp, *prev;
 
-	for (i = 0; i < core->core_nlwp; i++, lwp = list_next(lwp)) {
+	for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
+	    lwp = list_next(&core->core_lwp_head, lwp)) {
 		if (lwp->lwp_id == id) {
 			core->core_lwp = lwp;
 			return (lwp);
@@ -362,15 +360,14 @@ lwpid2info(struct ps_prochandle *P, lwpid_t id)
 		}
 	}
 
-	next = lwp;
+	prev = lwp;
 	if ((lwp = calloc(1, sizeof (lwp_info_t))) == NULL)
 		return (NULL);
 
-	list_link(lwp, next);
+	list_insert_before(&core->core_lwp_head, prev, lwp);
 	lwp->lwp_id = id;
 
 	core->core_lwp = lwp;
-	core->core_nlwp++;
 
 	return (lwp);
 }
@@ -2396,6 +2393,7 @@ Pfgrab_core(int core_fd, const char *aout_path, int *perr)
 	Pinit_ops(&P->ops, &P_core_ops);
 
 	Pinitsym(P);
+	Pinitfd(P);
 
 	/*
 	 * Fstat and open the core file and make sure it is a valid ELF core.
@@ -2418,7 +2416,8 @@ Pfgrab_core(int core_fd, const char *aout_path, int *perr)
 	}
 
 	P->data = core_info;
-	list_link(&core_info->core_lwp_head, NULL);
+	list_create(&core_info->core_lwp_head, sizeof (lwp_info_t),
+	    offsetof(lwp_info_t, lwp_list));
 	core_info->core_size = stbuf.st_size;
 	/*
 	 * In the days before adjustable core file content, this was the
@@ -2611,17 +2610,15 @@ Pfgrab_core(int core_fd, const char *aout_path, int *perr)
 
 #ifdef __x86
 	if (from_linux) {
-		size_t tcount, pid;
+		size_t pid;
 		lwp_info_t *lwp;
 
 		P->status.pr_dmodel = core_info->core_dmodel;
 
-		lwp = list_next(&core_info->core_lwp_head);
-
 		pid = P->status.pr_pid;
 
-		for (tcount = 0; tcount < core_info->core_nlwp;
-		    tcount++, lwp = list_next(lwp)) {
+		for (lwp = list_head(&core_info->core_lwp_head); lwp != NULL;
+		    lwp = list_next(&core_info->core_lwp_head, lwp)) {
 			dprintf("Linux thread with id %d\n", lwp->lwp_id);
 
 			/*
@@ -2810,7 +2807,7 @@ Pfgrab_core(int core_fd, const char *aout_path, int *perr)
 
 			(void) memset(fp, 0, sizeof (file_info_t));
 
-			list_link(fp, &P->file_head);
+			list_insert_head(&P->file_head, fp);
 			tmp->map_file = fp;
 			P->num_files++;
 
diff --git a/usr/src/lib/libproc/common/Pfdinfo.c b/usr/src/lib/libproc/common/Pfdinfo.c
index c822ec8434..36978d8e60 100644
--- a/usr/src/lib/libproc/common/Pfdinfo.c
+++ b/usr/src/lib/libproc/common/Pfdinfo.c
@@ -15,6 +15,7 @@
 /*
  * Copyright (c) 2013 Joyent, Inc.  All Rights reserved.
  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
+ * Copyright 2021 Oxide Computer Company
  */
 
 #include <limits.h>
@@ -24,6 +25,7 @@
 #include <dirent.h>
 #include <ctype.h>
 #include <string.h>
+#include <stddef.h>
 #include <sys/mkdev.h>
 
 #include "libproc.h"
@@ -34,6 +36,13 @@
  * Pfdinfo.c - obtain open file information.
  */
 
+void
+Pinitfd(struct ps_prochandle *P)
+{
+	list_create(&P->fd_head, sizeof (fd_info_t),
+	    offsetof(fd_info_t, fd_list));
+}
+
 /*
  * Allocate an fd_info structure and stick it on the list.
  * (Unless one already exists.)  The list is sorted in
@@ -43,16 +52,10 @@
 fd_info_t *
 Pfd2info(struct ps_prochandle *P, int fd)
 {
-	fd_info_t	*fip = list_next(&P->fd_head);
-	fd_info_t	*next;
-	int i;
-
-	if (fip == NULL) {
-		list_link(&P->fd_head, NULL);
-		fip = list_next(&P->fd_head);
-	}
+	fd_info_t	*fip, *next = NULL;
 
-	for (i = 0; i < P->num_fd; i++, fip = list_next(fip)) {
+	for (fip = list_head(&P->fd_head); fip != NULL;
+	    fip = list_next(&P->fd_head, fip)) {
 		if (fip->fd_info == NULL)
 			continue;
 
@@ -68,8 +71,7 @@ Pfd2info(struct ps_prochandle *P, int fd)
 	if ((fip = calloc(1, sizeof (*fip))) == NULL)
 		return (NULL);
 
-	list_link(fip, next ? next : (void *)&(P->fd_head));
-	P->num_fd++;
+	list_insert_before(&P->fd_head, next, fip);
 	return (fip);
 }
 
@@ -108,7 +110,7 @@ load_fdinfo(struct ps_prochandle *P)
 	 * This is an edge case it isn't worth adding additional state to
 	 * to eliminate.
 	 */
-	if (P->num_fd > 0)
+	if (!list_is_empty(&P->fd_head))
 		return;
 
 	if (P->state == PS_DEAD || P->state == PS_IDLE)
@@ -128,9 +130,8 @@ Pfdinfo_iter(struct ps_prochandle *P, proc_fdinfo_f *func, void *cd)
 
 	/* NB: We walk the list backwards. */
 
-	for (fip = list_prev(&P->fd_head);
-	    fip != (void *)&P->fd_head && fip != NULL;
-	    fip = list_prev(fip)) {
+	for (fip = list_tail(&P->fd_head); fip != NULL;
+	    fip = list_prev(&P->fd_head, fip)) {
 		if ((rv = func(cd, fip->fd_info)) != 0)
 			return (rv);
 	}
diff --git a/usr/src/lib/libproc/common/Pgcore.c b/usr/src/lib/libproc/common/Pgcore.c
index 8890d85efc..874579f055 100644
--- a/usr/src/lib/libproc/common/Pgcore.c
+++ b/usr/src/lib/libproc/common/Pgcore.c
@@ -636,14 +636,13 @@ count_sections(pgcore_t *pgc)
 {
 	struct ps_prochandle *P = pgc->P;
 	file_info_t *fptr;
-	uint_t cnt;
 	uint_t nshdrs = 0;
 
 	if (!(pgc->pgc_content & (CC_CONTENT_CTF | CC_CONTENT_SYMTAB)))
 		return (0);
 
-	fptr = list_next(&P->file_head);
-	for (cnt = P->num_files; cnt > 0; cnt--, fptr = list_next(fptr)) {
+	for (fptr = list_head(&P->file_head); fptr != NULL;
+	    fptr = list_next(&P->file_head, fptr)) {
 		int hit_symtab = 0;
 
 		Pbuild_file_symtab(P, fptr);
@@ -773,14 +772,13 @@ dump_sections(pgcore_t *pgc)
 {
 	struct ps_prochandle *P = pgc->P;
 	file_info_t *fptr;
-	uint_t cnt;
 	uint_t index = 1;
 
 	if (!(pgc->pgc_content & (CC_CONTENT_CTF | CC_CONTENT_SYMTAB)))
 		return (0);
 
-	fptr = list_next(&P->file_head);
-	for (cnt = P->num_files; cnt > 0; cnt--, fptr = list_next(fptr)) {
+	for (fptr = list_head(&P->file_head); fptr != NULL;
+	    fptr = list_next(&P->file_head, fptr)) {
 		int hit_symtab = 0;
 
 		Pbuild_file_symtab(P, fptr);
diff --git a/usr/src/lib/libproc/common/Pidle.c b/usr/src/lib/libproc/common/Pidle.c
index db00268f9b..eaf6c63078 100644
--- a/usr/src/lib/libproc/common/Pidle.c
+++ b/usr/src/lib/libproc/common/Pidle.c
@@ -191,6 +191,7 @@ Pgrab_file(const char *fname, int *perr)
 	P->info_valid = -1;
 	Pinit_ops(&P->ops, &P_idle_ops);
 	Pinitsym(P);
+	Pinitfd(P);
 
 	if ((elf = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
 		*perr = G_ELF;
@@ -241,7 +242,7 @@ Pgrab_file(const char *fname, int *perr)
 	}
 
 	P->num_files++;
-	list_link(fp, &P->file_head);
+	list_insert_head(&P->file_head, fp);
 
 	if (gelf_getehdr(elf, &ehdr) == NULL) {
 		*perr = G_STRANGE;
diff --git a/usr/src/lib/libproc/common/Plwpregs.c b/usr/src/lib/libproc/common/Plwpregs.c
index bf35c91ccf..ffc3c6e1e3 100644
--- a/usr/src/lib/libproc/common/Plwpregs.c
+++ b/usr/src/lib/libproc/common/Plwpregs.c
@@ -52,10 +52,10 @@ static lwp_info_t *
 getlwpcore(struct ps_prochandle *P, lwpid_t lwpid)
 {
 	core_info_t *core = P->data;
-	lwp_info_t *lwp = list_next(&core->core_lwp_head);
-	uint_t i;
+	lwp_info_t *lwp;
 
-	for (i = 0; i < core->core_nlwp; i++, lwp = list_next(lwp)) {
+	for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
+	    lwp = list_next(&core->core_lwp_head, lwp)) {
 		if (lwp->lwp_id == lwpid)
 			return (lwp);
 	}
diff --git a/usr/src/lib/libproc/common/Pservice.c b/usr/src/lib/libproc/common/Pservice.c
index 03d013364f..361cf4ab98 100644
--- a/usr/src/lib/libproc/common/Pservice.c
+++ b/usr/src/lib/libproc/common/Pservice.c
@@ -177,10 +177,10 @@ ps_lgetxregsize(struct ps_prochandle *P, lwpid_t lwpid, int *xrsize)
 
 	if (P->state == PS_DEAD) {
 		core_info_t *core = P->data;
-		lwp_info_t *lwp = list_next(&core->core_lwp_head);
-		uint_t i;
+		lwp_info_t *lwp;
 
-		for (i = 0; i < core->core_nlwp; i++, lwp = list_next(lwp)) {
+		for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
+		    lwp = list_next(&core->core_lwp_head, lwp)) {
 			if (lwp->lwp_id == lwpid) {
 				if (lwp->lwp_xregs != NULL)
 					*xrsize = sizeof (prxregset_t);
@@ -332,7 +332,7 @@ ps_pbrandname(struct ps_prochandle *P, char *buf, size_t len)
  */
 ps_err_e
 ps_pglobal_lookup(struct ps_prochandle *P, const char *object_name,
-	const char *sym_name, psaddr_t *sym_addr)
+    const char *sym_name, psaddr_t *sym_addr)
 {
 	GElf_Sym sym;
 
@@ -355,7 +355,7 @@ ps_pglobal_lookup(struct ps_prochandle *P, const char *object_name,
  */
 ps_err_e
 ps_pglobal_sym(struct ps_prochandle *P, const char *object_name,
-	const char *sym_name, ps_sym_t *symp)
+    const char *sym_name, ps_sym_t *symp)
 {
 #if defined(_ILP32)
 	GElf_Sym sym;
diff --git a/usr/src/lib/libproc/common/Psymtab.c b/usr/src/lib/libproc/common/Psymtab.c
index f20f6f4f81..e6fc676ee0 100644
--- a/usr/src/lib/libproc/common/Psymtab.c
+++ b/usr/src/lib/libproc/common/Psymtab.c
@@ -23,6 +23,7 @@
  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2016 Joyent, Inc.
  * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright 2021 Oxide Computer Company
  */
 
 #include <assert.h>
@@ -197,7 +198,7 @@ file_info_new(struct ps_prochandle *P, map_info_t *mptr)
 	if ((fptr = calloc(1, sizeof (file_info_t))) == NULL)
 		return (NULL);
 
-	list_link(fptr, &P->file_head);
+	list_insert_tail(&P->file_head, fptr);
 	(void) strcpy(fptr->file_pname, mptr->map_pmap.pr_mapname);
 	mptr->map_file = fptr;
 	fptr->file_ref = 1;
@@ -262,7 +263,7 @@ static void
 file_info_free(struct ps_prochandle *P, file_info_t *fptr)
 {
 	if (--fptr->file_ref == 0) {
-		list_unlink(fptr);
+		list_remove(&P->file_head, fptr);
 		if (fptr->file_symtab.sym_elf) {
 			(void) elf_end(fptr->file_symtab.sym_elf);
 			free(fptr->file_symtab.sym_elfmem);
@@ -591,12 +592,11 @@ void
 Pupdate_syms(struct ps_prochandle *P)
 {
 	file_info_t *fptr;
-	int i;
 
 	Pupdate_maps(P);
 
-	for (i = 0, fptr = list_next(&P->file_head); i < P->num_files;
-	    i++, fptr = list_next(fptr)) {
+	for (fptr = list_head(&P->file_head); fptr != NULL;
+	    fptr = list_next(&P->file_head, fptr)) {
 		Pbuild_file_symtab(P, fptr);
 		(void) Pbuild_file_ctf(P, fptr);
 	}
@@ -856,7 +856,7 @@ Plmid_to_ctf(struct ps_prochandle *P, Lmid_t lmid, const char *name)
 	 */
 	if (P->state == PS_IDLE && name == PR_OBJ_EXEC && P->info_valid == 1 &&
 	    P->num_files == 1 && P->mappings == NULL) {
-		fptr = list_next(&P->file_head);
+		fptr = list_head(&P->file_head);
 	}
 
 	if (fptr == NULL) {
@@ -990,7 +990,6 @@ build_map_symtab(struct ps_prochandle *P, map_info_t *mptr)
 {
 	prmap_t *pmap = &mptr->map_pmap;
 	file_info_t *fptr;
-	uint_t i;
 
 	if ((fptr = mptr->map_file) != NULL) {
 		Pbuild_file_symtab(P, fptr);
@@ -1004,8 +1003,8 @@ build_map_symtab(struct ps_prochandle *P, map_info_t *mptr)
 	 * Attempt to find a matching file.
 	 * (A file can be mapped at several different addresses.)
 	 */
-	for (i = 0, fptr = list_next(&P->file_head); i < P->num_files;
-	    i++, fptr = list_next(fptr)) {
+	for (fptr = list_head(&P->file_head); fptr != NULL;
+	    fptr = list_next(&P->file_head, fptr)) {
 		if (strcmp(fptr->file_pname, pmap->pr_mapname) == 0 &&
 		    fptr->file_lo && is_mapping_in_file(P, mptr, fptr)) {
 			mptr->map_file = fptr;
@@ -2907,7 +2906,7 @@ Pxlookup_by_name(
 		/* create all the file_info_t's for all the mappings */
 		(void) Prd_agent(P);
 		cnt = P->num_files;
-		fptr = list_next(&P->file_head);
+		fptr = list_head(&P->file_head);
 	} else {
 		cnt = 1;
 		if ((mptr = object_name_to_map(P, lmid, oname)) == NULL ||
@@ -2922,7 +2921,7 @@ Pxlookup_by_name(
 	 * This means that a name such as "puts" will match the puts function
 	 * in libc instead of matching the puts PLT entry in the a.out file.
 	 */
-	for (; cnt > 0; cnt--, fptr = list_next(fptr)) {
+	for (; cnt > 0; cnt--, fptr = list_next(&P->file_head, fptr)) {
 		Pbuild_file_symtab(P, fptr);
 
 		if (fptr->file_elf == NULL)
@@ -3040,14 +3039,13 @@ i_Pobject_iter(struct ps_prochandle *P, boolean_t lmresolve,
 {
 	map_info_t *mptr;
 	file_info_t *fptr;
-	uint_t cnt;
 	int rc = 0;
 
 	(void) Prd_agent(P); /* create file_info_t's for all the mappings */
 	Pupdate_maps(P);
 
-	for (cnt = P->num_files, fptr = list_next(&P->file_head);
-	    cnt; cnt--, fptr = list_next(fptr)) {
+	for (fptr = list_head(&P->file_head); fptr != NULL;
+	    fptr = list_next(&P->file_head, fptr)) {
 		const char *lname;
 
 		if (lmresolve && (fptr->file_rname != NULL))
@@ -3354,7 +3352,8 @@ void
 Pinitsym(struct ps_prochandle *P)
 {
 	P->num_files = 0;
-	list_link(&P->file_head, NULL);
+	list_create(&P->file_head, sizeof (file_info_t),
+	    offsetof(file_info_t, file_list));
 }
 
 /*
diff --git a/usr/src/lib/libproc/common/Putil.c b/usr/src/lib/libproc/common/Putil.c
index e42ac08de5..ae66e08c85 100644
--- a/usr/src/lib/libproc/common/Putil.c
+++ b/usr/src/lib/libproc/common/Putil.c
@@ -37,40 +37,6 @@
 #include "Putil.h"
 
 /*
- * Place the new element on the list prior to the existing element.
- */
-void
-list_link(void *new, void *existing)
-{
-	plist_t *p = new;
-	plist_t *q = existing;
-
-	if (q) {
-		p->list_forw = q;
-		p->list_back = q->list_back;
-		q->list_back->list_forw = p;
-		q->list_back = p;
-	} else {
-		p->list_forw = p->list_back = p;
-	}
-}
-
-/*
- * Unchain the specified element from a list.
- */
-void
-list_unlink(void *old)
-{
-	plist_t *p = old;
-
-	if (p->list_forw != p) {
-		p->list_back->list_forw = p->list_forw;
-		p->list_forw->list_back = p->list_back;
-	}
-	p->list_forw = p->list_back = p;
-}
-
-/*
  * Routines to manipulate sigset_t, fltset_t, or sysset_t.  These routines
  * are provided as equivalents for the <sys/procfs.h> macros prfillset,
  * premptyset, praddset, and prdelset.  These functions are preferable
diff --git a/usr/src/lib/libproc/common/Putil.h b/usr/src/lib/libproc/common/Putil.h
index 57814a9a7f..381d164a69 100644
--- a/usr/src/lib/libproc/common/Putil.h
+++ b/usr/src/lib/libproc/common/Putil.h
@@ -35,23 +35,6 @@ extern "C" {
 #endif
 
 /*
- * Circular doubly-linked list:
- */
-typedef struct P_list {
-	struct P_list	*list_forw;
-	struct P_list	*list_back;
-} plist_t;
-
-/*
- * Routines to manipulate linked lists:
- */
-extern void list_link(void *, void *);
-extern void list_unlink(void *);
-
-#define	list_next(elem)	(void *)(((plist_t *)(elem))->list_forw)
-#define	list_prev(elem)	(void *)(((plist_t *)(elem))->list_back)
-
-/*
  * Routines to manipulate sigset_t, fltset_t, or sysset_t.
  */
 extern void prset_fill(void *, size_t);
diff --git a/usr/src/lib/libproc/sparc/Pisadep.c b/usr/src/lib/libproc/sparc/Pisadep.c
index c3bbd99788..29575d05ae 100644
--- a/usr/src/lib/libproc/sparc/Pisadep.c
+++ b/usr/src/lib/libproc/sparc/Pisadep.c
@@ -188,11 +188,11 @@ read_gwin(struct ps_prochandle *P, struct rwindow *rwp, uintptr_t sp)
 
 	if (P->state == PS_DEAD) {
 		core_info_t *core = P->data;
-		lwp_info_t *lwp = list_next(&core->core_lwp_head);
-		uint_t n;
+		lwp_info_t *lwp;
 		int i;
 
-		for (n = 0; n < core->core_nlwp; n++, lwp = list_next(lwp)) {
+		for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
+		    lwp = list_next(&core->core_lwp_head, lwp)) {
 			gwindows_t *gwin = lwp->lwp_gwins;
 
 			if (gwin == NULL)
@@ -253,7 +253,7 @@ ucontext_n_to_prgregs(const ucontext_t *src, prgregset_t dst)
 
 int
 Pstack_iter(struct ps_prochandle *P, const prgregset_t regs,
-	proc_stack_f *func, void *arg)
+    proc_stack_f *func, void *arg)
 {
 	prgreg_t *prevfp = NULL;
 	uint_t pfpsize = 0;
diff --git a/usr/src/lib/libproc/sparcv9/Pisadep.c b/usr/src/lib/libproc/sparcv9/Pisadep.c
index 6aff474ec0..69a212f998 100644
--- a/usr/src/lib/libproc/sparcv9/Pisadep.c
+++ b/usr/src/lib/libproc/sparcv9/Pisadep.c
@@ -236,11 +236,11 @@ read_gwin(struct ps_prochandle *P, struct rwindow *rwp, uintptr_t sp)
 
 	if (P->state == PS_DEAD) {
 		core_info_t *core = P->data;
-		lwp_info_t *lwp = list_next(&core->core_lwp_head);
-		uint_t n;
+		lwp_info_t *lwp;
 		int i;
 
-		for (n = 0; n < core->core_nlwp; n++, lwp = list_next(lwp)) {
+		for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
+		    lwp = list_next(&core->core_lwp_head, lwp)) {
 			gwindows_t *gwin = lwp->lwp_gwins;
 
 			if (gwin == NULL)
@@ -335,7 +335,7 @@ ucontext_32_to_prgregs(const ucontext32_t *src, prgregset_t dst)
 
 int
 Pstack_iter(struct ps_prochandle *P, const prgregset_t regs,
-	proc_stack_f *func, void *arg)
+    proc_stack_f *func, void *arg)
 {
 	prgreg_t *prevfp = NULL;
 	uint_t pfpsize = 0;
diff --git a/usr/src/pkg/manifests/developer-debug-mdb.mf b/usr/src/pkg/manifests/developer-debug-mdb.mf
index 63c7982c3c..4e2322ad1c 100644
--- a/usr/src/pkg/manifests/developer-debug-mdb.mf
+++ b/usr/src/pkg/manifests/developer-debug-mdb.mf
@@ -211,7 +211,6 @@ file path=usr/lib/mdb/kvm/$(ARCH64)/usba.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/ld.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libavl.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libc.so group=sys mode=0555
-file path=usr/lib/mdb/proc/$(ARCH64)/libcmdutils.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libnvpair.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libproc.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libpython$(PYTHON_VERSION).so group=sys \
@@ -222,13 +221,13 @@ file path=usr/lib/mdb/proc/$(ARCH64)/libsysevent.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libtopo.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libumem.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/libuutil.so group=sys mode=0555
+file path=usr/lib/mdb/proc/$(ARCH64)/list.so group=sys mode=0555
 file path=usr/lib/mdb/proc/$(ARCH64)/mdb_ds.so group=sys mode=0555
 $(i386_ONLY)file path=usr/lib/mdb/proc/$(ARCH64)/mdb_test.so group=sys \
     mode=0555
 file path=usr/lib/mdb/proc/ld.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libavl.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libc.so group=sys mode=0555
-file path=usr/lib/mdb/proc/libcmdutils.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libnvpair.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libproc.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libpython$(PYTHON_VERSION).so group=sys mode=0555
@@ -237,6 +236,7 @@ file path=usr/lib/mdb/proc/libsysevent.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libtopo.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libumem.so group=sys mode=0555
 file path=usr/lib/mdb/proc/libuutil.so group=sys mode=0555
+file path=usr/lib/mdb/proc/list.so group=sys mode=0555
 file path=usr/lib/mdb/proc/mdb_ds.so group=sys mode=0555
 file path=usr/lib/mdb/proc/svc.configd.so group=sys mode=0555
 file path=usr/lib/mdb/proc/svc.startd.so group=sys mode=0555