OS-7931 ::refstr would be useful

OS-7932 ::ps -s could show service FMRIs
OS-7934 ptree could show service FMRIs
OS-3513 ptools should see more process arguments
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Jason King <jason.king@joyent.com>
Approved by: Jerry Jelinek <jerry.jelinek@joyent.com>

14 files changed, 213 insertions, 221 deletions

diff --git a/usr/src/uts/common/brand/lx/os/lx_brand.c b/usr/src/uts/common/brand/lx/os/lx_brand.c
index 83fbd6adb7..b6038fca07 100644
--- a/usr/src/uts/common/brand/lx/os/lx_brand.c
+++ b/usr/src/uts/common/brand/lx/os/lx_brand.c
@@ -379,8 +379,6 @@ lx_setbrand(proc_t *p)
 {
 	/* Send SIGCHLD to parent by default when child exits */
 	ptolxproc(p)->l_signal = stol_signo[SIGCHLD];
-
-	lx_read_argv_bounds(p);
 }
 
 /* ARGSUSED */
diff --git a/usr/src/uts/common/brand/lx/os/lx_misc.c b/usr/src/uts/common/brand/lx/os/lx_misc.c
index b73e7f430a..726c3c7915 100644
--- a/usr/src/uts/common/brand/lx/os/lx_misc.c
+++ b/usr/src/uts/common/brand/lx/os/lx_misc.c
@@ -135,11 +135,6 @@ lx_exec()
 	lx_restore(lwp);
 	kpreempt_enable();
 
-	/* Grab the updated argv bounds */
-	mutex_enter(&p->p_lock);
-	lx_read_argv_bounds(p);
-	mutex_exit(&p->p_lock);
-
 	/*
 	 * The exec syscall doesn't return (so we don't call lx_syscall_return)
 	 * but for our ptrace emulation we need to do this so that a tracer
@@ -1058,72 +1053,6 @@ stol_ksiginfo32_copyout(k_siginfo_t *sip, void *ulxsip)
 }
 #endif
 
-/*
- * Linux uses the original bounds of the argv array when determining the
- * contents of /proc/<pid/cmdline.  We mimic those bounds using argv[0] and
- * envp[0] as the beginning and end, respectively.
- */
-void
-lx_read_argv_bounds(proc_t *p)
-{
-	user_t *up = PTOU(p);
-	lx_proc_data_t *pd = ptolxproc(p);
-	uintptr_t addr_arg = up->u_argv;
-	uintptr_t addr_env = up->u_envp;
-	uintptr_t arg_start = 0, env_start = 0, env_end = 0;
-	int i = 0;
-
-	VERIFY(pd != NULL);
-	VERIFY(MUTEX_HELD(&p->p_lock));
-
-	/*
-	 * Use AT_SUN_PLATFORM in the aux vector to find the end of the envp
-	 * strings.
-	 */
-	for (i = 0; i < __KERN_NAUXV_IMPL; i++) {
-		if (up->u_auxv[i].a_type == AT_SUN_PLATFORM) {
-			env_end = (uintptr_t)up->u_auxv[i].a_un.a_val;
-		}
-	}
-
-	/*
-	 * If we come through here for a kernel process (zsched), which happens
-	 * with our cgroupfs when we fork the release agent, then u_argv and
-	 * u_envp will be NULL. While this won't cause a failure, it does
-	 * cause a lot of overhead when the fuword causes a fault, which leads
-	 * to a large amount of stack growth and anonymous memory allocation,
-	 * all of which is pointless since the first page can't be mapped.
-	 */
-	if (addr_arg != (uintptr_t)NULL || addr_env != (uintptr_t)NULL) {
-		mutex_exit(&p->p_lock);
-#if defined(_LP64)
-		if (p->p_model != DATAMODEL_NATIVE) {
-			uint32_t buf32;
-			if (fuword32((void *)addr_arg, &buf32) == 0) {
-				arg_start = (uintptr_t)buf32;
-			}
-			if (fuword32((void *)addr_env, &buf32) == 0) {
-				env_start = (uintptr_t)buf32;
-			}
-		} else
-#endif /* defined(_LP64) */
-		{
-			ulong_t buf;
-			if (fulword((void *)addr_arg, &buf) == 0) {
-				arg_start = (uintptr_t)buf;
-			}
-			if (fulword((void *)addr_env, &buf) == 0) {
-				env_start = (uintptr_t)buf;
-			}
-		}
-		mutex_enter(&p->p_lock);
-	}
-
-	pd->l_args_start = arg_start;
-	pd->l_envs_start = env_start;
-	pd->l_envs_end = env_end;
-}
-
 /* Given an LX LWP, determine where user register state is stored. */
 lx_regs_location_t
 lx_regs_location(lx_lwp_data_t *lwpd, void **ucp, boolean_t for_write)
diff --git a/usr/src/uts/common/brand/lx/procfs/lx_prvnops.c b/usr/src/uts/common/brand/lx/procfs/lx_prvnops.c
index bcfdd346da..90e8fbe4d5 100644
--- a/usr/src/uts/common/brand/lx/procfs/lx_prvnops.c
+++ b/usr/src/uts/common/brand/lx/procfs/lx_prvnops.c
@@ -83,10 +83,11 @@
 #include <sys/socketvar.h>
 #include <fs/sockfs/socktpi.h>
 #include <sys/random.h>
+#include <sys/procfs.h>
 
 /* Dependent on procfs */
 extern kthread_t *prchoose(proc_t *);
-extern int prreadargv(proc_t *, char *, size_t, size_t *);
+extern int prreadcmdline(proc_t *, char *, size_t, size_t *);
 extern int prreadenvv(proc_t *, char *, size_t, size_t *);
 extern int prreadbuf(proc_t *, uintptr_t, uint8_t *, size_t, size_t *);
 
@@ -332,10 +333,9 @@ extern swrand_stats_t swrand_stats;
 #define	FOURGB	4294967295ULL
 
 /*
- * The maximum length of the concatenation of argument vector strings we
- * will return to the user via the branded procfs. Likewise for the env vector.
+ * The maximum length of the concatenation of env vector strings we
+ * will return to the user via the branded procfs.
  */
-int lxpr_maxargvlen = 4096;
 int lxpr_maxenvvlen = 4096;
 
 /*
@@ -1501,77 +1501,6 @@ lxpr_read_pid_cgroup(lxpr_node_t *lxpnp, lxpr_uiobuf_t *uiobuf)
 	lxpr_uiobuf_printf(uiobuf, "1:name=systemd:/\n");
 }
 
-static void
-lxpr_copy_cmdline(proc_t *p, lx_proc_data_t *pd, lxpr_uiobuf_t *uiobuf)
-{
-	uio_t *uiop = uiobuf->uiop;
-	char *buf = uiobuf->buffer;
-	int bsz = uiobuf->buffsize;
-	boolean_t env_overflow = B_FALSE;
-	uintptr_t pos = pd->l_args_start + uiop->uio_offset;
-	uintptr_t estart = pd->l_envs_start;
-	uintptr_t eend = pd->l_envs_end;
-	size_t chunk, copied;
-	int err = 0;
-
-	/* Do not bother with data beyond the end of the envp strings area. */
-	if (pos > eend) {
-		return;
-	}
-	mutex_exit(&p->p_lock);
-
-	/*
-	 * If the starting or ending bounds are outside the argv strings area,
-	 * check to see if the process has overwritten the terminating NULL.
-	 * If not, no data needs to be copied from oustide the argv area.
-	 */
-	if (pos >= estart || (pos + uiop->uio_resid) >= estart) {
-		uint8_t term;
-		if (uread(p, &term, sizeof (term), estart - 1) != 0) {
-			err = EFAULT;
-		} else if (term != 0) {
-			env_overflow = B_TRUE;
-		}
-	}
-
-	/* Data between astart and estart-1 can be copied freely. */
-	while (pos < estart && uiop->uio_resid > 0 && err == 0) {
-		chunk = MIN(estart - pos, uiop->uio_resid);
-		chunk = MIN(chunk, bsz);
-
-		if (prreadbuf(p, pos, (uint8_t *)buf, chunk, &copied) != 0 ||
-		    copied != chunk) {
-			err = EFAULT;
-			break;
-		}
-		err = uiomove(buf, copied, UIO_READ, uiop);
-		pos += copied;
-	}
-
-	/*
-	 * Onward from estart, data is copied as a contiguous string.  To
-	 * protect env data from potential snooping, only one buffer-sized copy
-	 * is allowed to avoid complex seek logic.
-	 */
-	if (err == 0 && env_overflow && pos == estart && uiop->uio_resid > 0) {
-		chunk = MIN(eend - pos, uiop->uio_resid);
-		chunk = MIN(chunk, bsz);
-		if (prreadbuf(p, pos, (uint8_t *)buf, chunk, &copied) == 0) {
-			int len = strnlen(buf, copied);
-			if (len > 0) {
-				err = uiomove(buf, len, UIO_READ, uiop);
-			}
-		}
-	}
-
-	uiobuf->error = err;
-	/* reset any uiobuf state */
-	uiobuf->pos = uiobuf->buffer;
-	uiobuf->beg = 0;
-
-	mutex_enter(&p->p_lock);
-}
-
 /*
  * lxpr_read_pid_cmdline(): read argument vector from process
  */
@@ -1580,8 +1509,8 @@ lxpr_read_pid_cmdline(lxpr_node_t *lxpnp, lxpr_uiobuf_t *uiobuf)
 {
 	proc_t *p;
 	char *buf;
-	size_t asz = lxpr_maxargvlen, sz;
-	lx_proc_data_t *pd;
+	size_t asz = PRMAXARGVLEN, sz;
+	int r;
 
 	ASSERT(lxpnp->lxpr_type == LXPR_PID_CMDLINE ||
 	    lxpnp->lxpr_type == LXPR_PID_TID_CMDLINE);
@@ -1594,23 +1523,16 @@ lxpr_read_pid_cmdline(lxpr_node_t *lxpnp, lxpr_uiobuf_t *uiobuf)
 		return;
 	}
 
-	if ((pd = ptolxproc(p)) != NULL && pd->l_args_start != 0 &&
-	    pd->l_envs_start != 0 && pd->l_envs_end != 0) {
-		/* Use Linux-style argv bounds if possible. */
-		lxpr_copy_cmdline(p, pd, uiobuf);
-		lxpr_unlock(p);
-	} else {
-		int r;
+	r = prreadcmdline(p, buf, asz, &sz);
 
-		r = prreadargv(p, buf, asz, &sz);
-		lxpr_unlock(p);
+	lxpr_unlock(p);
 
-		if (r != 0) {
-			lxpr_uiobuf_seterr(uiobuf, EINVAL);
-		} else {
-			lxpr_uiobuf_write(uiobuf, buf, sz);
-		}
+	if (r != 0) {
+		lxpr_uiobuf_seterr(uiobuf, EINVAL);
+	} else {
+		lxpr_uiobuf_write(uiobuf, buf, sz);
 	}
+
 	kmem_free(buf, asz);
 }
 
diff --git a/usr/src/uts/common/brand/lx/sys/lx_brand.h b/usr/src/uts/common/brand/lx/sys/lx_brand.h
index 9c1579cc82..90d87d78a8 100644
--- a/usr/src/uts/common/brand/lx/sys/lx_brand.h
+++ b/usr/src/uts/common/brand/lx/sys/lx_brand.h
@@ -24,7 +24,7 @@
  */
 
 /*
- * Copyright 2018 Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  */
 
 #ifndef _LX_BRAND_H
@@ -132,8 +132,8 @@ typedef enum lx_ptrace_options {
 } lx_ptrace_options_t;
 
 #define	LX_PTRACE_O_ALL							\
-	(LX_PTRACE_O_TRACESYSGOOD | LX_PTRACE_O_TRACEFORK | 		\
-	LX_PTRACE_O_TRACEVFORK | LX_PTRACE_O_TRACECLONE | 		\
+	(LX_PTRACE_O_TRACESYSGOOD | LX_PTRACE_O_TRACEFORK |		\
+	LX_PTRACE_O_TRACEVFORK | LX_PTRACE_O_TRACECLONE |		\
 	LX_PTRACE_O_TRACEEXEC | LX_PTRACE_O_TRACEVFORKDONE |		\
 	LX_PTRACE_O_TRACEEXIT | LX_PTRACE_O_TRACESECCOMP)
 #endif /* !_ASM */
@@ -344,11 +344,6 @@ typedef struct lx_proc_data {
 	uint_t l_io_ctx_cnt;
 	struct lx_io_ctx  **l_io_ctxs;
 
-	/* original start/end bounds of arg/env string data */
-	uintptr_t l_args_start;
-	uintptr_t l_envs_start;
-	uintptr_t l_envs_end;
-
 	/* Override zone-wide settings for uname release and version */
 	char l_uname_release[LX_KERN_RELEASE_MAX];
 	char l_uname_version[LX_KERN_VERSION_MAX];
@@ -365,7 +360,7 @@ typedef struct lx_proc_data {
 	lx_segmap_t l_remap_anoncache[LX_REMAP_ANONCACHE_NENTRIES];
 
 	/* Block all signals to all threads; used during vfork */
-	uint_t	 l_block_all_signals;
+	uint_t l_block_all_signals;
 } lx_proc_data_t;
 
 #endif	/* _KERNEL */
@@ -545,7 +540,7 @@ struct lx_lwp_data {
 	lx_ptrace_accord_t *br_ptrace_tracer; /* accord tracing this LWP */
 	list_node_t br_ptrace_linkage;	/* linkage for lxpa_tracees list */
 
-	ushort_t br_ptrace_whystop; 	/* stop reason, 0 for no stop */
+	ushort_t br_ptrace_whystop;	/* stop reason, 0 for no stop */
 	ushort_t br_ptrace_whatstop;	/* stop sub-reason */
 
 	int32_t br_ptrace_stopsig;	/* stop signal, 0 for no signal */
diff --git a/usr/src/uts/common/brand/lx/sys/lx_misc.h b/usr/src/uts/common/brand/lx/sys/lx_misc.h
index 0418d3e9f9..e81a1597f3 100644
--- a/usr/src/uts/common/brand/lx/sys/lx_misc.h
+++ b/usr/src/uts/common/brand/lx/sys/lx_misc.h
@@ -10,7 +10,7 @@
  */
 
 /*
- * Copyright 2017 Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  */
 
 #ifndef _SYS__LX_MISC_H
@@ -62,7 +62,6 @@ extern int ltos_at_flag(int, int, boolean_t);
 #if defined(_SYSCALL32_IMPL)
 extern int stol_ksiginfo32_copyout(k_siginfo_t *, void *);
 #endif
-extern void lx_read_argv_bounds(proc_t *p);
 
 typedef enum lx_regs_location {
 	LX_REG_LOC_UNAVAIL,
diff --git a/usr/src/uts/common/contract/process.c b/usr/src/uts/common/contract/process.c
index e46cbd3abf..6e43bd7aef 100644
--- a/usr/src/uts/common/contract/process.c
+++ b/usr/src/uts/common/contract/process.c
@@ -21,7 +21,7 @@
 /*
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
- * Copyright 2016 Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  */
 
 #include <sys/mutex.h>
@@ -737,13 +737,11 @@ contract_process_status(contract_t *ct, zone_t *zone, int detail, nvlist_t *nvl,
 	 * if we are in a local zone and svc_fmri was inherited from
 	 * the global zone, we provide fake svc_fmri and svc_ctid
 	 */
-	if (local_svc_zone_enter == 0||
+	if (local_svc_zone_enter == 0 ||
 	    zone->zone_uniqid == GLOBAL_ZONEUNIQID) {
 		if (detail > CTD_COMMON) {
 			VERIFY(nvlist_add_int32(nvl, CTPS_SVC_CTID,
 			    ctp->conp_svc_ctid) == 0);
-		}
-		if (detail == CTD_ALL) {
 			VERIFY(nvlist_add_string(nvl, CTPS_SVC_FMRI,
 			    refstr_value(ctp->conp_svc_fmri)) == 0);
 		}
@@ -751,8 +749,6 @@ contract_process_status(contract_t *ct, zone_t *zone, int detail, nvlist_t *nvl,
 		if (detail > CTD_COMMON) {
 			VERIFY(nvlist_add_int32(nvl, CTPS_SVC_CTID,
 			    local_svc_zone_enter) == 0);
-		}
-		if (detail == CTD_ALL) {
 			VERIFY(nvlist_add_string(nvl, CTPS_SVC_FMRI,
 			    CT_PR_SVC_FMRI_ZONE_ENTER) == 0);
 		}
diff --git a/usr/src/uts/common/fs/proc/prargv.c b/usr/src/uts/common/fs/proc/prargv.c
index 40d47598ac..60d098d125 100644
--- a/usr/src/uts/common/fs/proc/prargv.c
+++ b/usr/src/uts/common/fs/proc/prargv.c
@@ -28,7 +28,7 @@
  * returned to the caller via 'rdsz'.
  */
 int
-prreadbuf(proc_t *p, uintptr_t ustart, uint8_t *buf, size_t sz, size_t *rdsz)
+prreadbuf(proc_t *p, uintptr_t ustart, char *buf, size_t sz, size_t *rdsz)
 {
 	int error = 0;
 	size_t rem = sz;
@@ -63,6 +63,95 @@ prreadbuf(proc_t *p, uintptr_t ustart, uint8_t *buf, size_t sz, size_t *rdsz)
 	return (error);
 }
 
+
+/*
+ * Effectively a truncating version of copyinstr().
+ *
+ * The resulting string is guaranteed to be truncated to fit within the buffer
+ * (hence sz == 0 is not supported). The returned size includes the truncating
+ * NUL.
+ */
+int
+prreadstr(proc_t *p, uintptr_t ustart, char *buf, size_t bufsz, size_t *rdsz)
+{
+	size_t slen;
+	int err;
+
+	VERIFY(bufsz != 0);
+
+	if ((err = prreadbuf(p, ustart, buf, bufsz, &slen)) != 0)
+		return (err);
+
+	slen = strnlen(buf, slen);
+
+	if (slen == bufsz)
+		slen--;
+
+	buf[slen++] = '\0';
+
+	if (rdsz != NULL)
+		*rdsz = slen;
+	return (0);
+}
+
+/*
+ * /proc/pid/cmdline: Linux-compatible '\0'-separated process argv.
+ *
+ * Unlike /proc/pid/argv, this looks at the exec()-time argv string area, rather
+ * than starting from the argv[] array. Thus changes to the array are not
+ * noticed, but direct modifications of the string are visible here. Since it's
+ * common for applications to expect it, we implement the Linux semantics here.
+ *
+ * There is special handling if the process has modified its argv: if the last
+ * byte of the argv string area is no longer NUL, then we presume that it has
+ * done setproctitle() or similar, and we should copy it as a single string from
+ * the start, even though it overflows into the env string area. Note that we
+ * can't use copyinstr() as that returns ENAMETOOLONG rather than truncating as
+ * we need.
+ *
+ * Otherwise, we provide the argv string area in toto.
+ */
+int
+prreadcmdline(proc_t *p, char *buf, size_t bufsz, size_t *slen)
+{
+	user_t *up = &p->p_user;
+	uint8_t term;
+	int err = 0;
+
+	VERIFY(bufsz == PRMAXARGVLEN);
+	VERIFY(MUTEX_HELD(&p->p_lock));
+
+	if ((p->p_flag & SSYS) || p->p_as == &kas || up->u_argvstrsize == 0) {
+		bcopy(up->u_psargs, buf, MIN(bufsz, sizeof (up->u_psargs)));
+		buf[bufsz - 1] = '\0';
+		*slen = strlen(buf) + 1;
+		return (0);
+	}
+
+	VERIFY(up->u_argvstrs != (uintptr_t)NULL);
+
+	mutex_exit(&p->p_lock);
+
+	if (uread(p, &term, sizeof (term),
+	    up->u_argvstrs + up->u_argvstrsize - 1) != 0) {
+		err = EFAULT;
+		goto out;
+	}
+
+	if (term != '\0') {
+		err = prreadstr(p, up->u_argvstrs, buf, bufsz, slen);
+	} else {
+		size_t size = MIN(bufsz, up->u_argvstrsize);
+		err = prreadbuf(p, up->u_argvstrs, buf, size, slen);
+	}
+
+out:
+	mutex_enter(&p->p_lock);
+	VERIFY(p->p_proc_flag & P_PR_LOCK);
+	return (err);
+}
+
+
 /*
  * Attempt to read the argument vector (argv) from this process.  The caller
  * must hold the p_lock mutex, and have marked the process P_PR_LOCK (e.g. via
@@ -113,8 +202,8 @@ prreadargv(proc_t *p, char *buf, size_t bufsz, size_t *slen)
 	 * while we do I/O to avoid deadlock with the clock thread.
 	 */
 	mutex_exit(&p->p_lock);
-	if ((error = prreadbuf(p, up->u_argv, (uint8_t *)argv, argvsz,
-	    NULL)) != 0) {
+	if ((error = prreadbuf(p, up->u_argv, (char *)argv,
+	    argvsz, NULL)) != 0) {
 		kmem_free(argv, argvsz);
 		mutex_enter(&p->p_lock);
 		VERIFY(p->p_proc_flag & P_PR_LOCK);
@@ -175,7 +264,7 @@ retry:
 		 * Read string data for this argument.  Leave room
 		 * in the buffer for a final NUL terminator.
 		 */
-		if ((error = prreadbuf(p, arg, (uint8_t *)&buf[pos], trysz,
+		if ((error = prreadbuf(p, arg, (char *)&buf[pos], trysz,
 		    &rdsz)) != 0) {
 			/*
 			 * There was a problem reading this string
@@ -288,7 +377,7 @@ prreadenvv(proc_t *p, char *buf, size_t bufsz, size_t *slen)
 	for (cnt = 0, tmpp = up->u_envp; cnt < bound; cnt++, tmpp += rdsz) {
 		caddr_t tmp = NULL;
 
-		if ((error = prreadbuf(p, tmpp, (uint8_t *)&tmp, rdsz,
+		if ((error = prreadbuf(p, tmpp, (char *)&tmp, rdsz,
 		    NULL)) != 0) {
 			mutex_enter(&p->p_lock);
 			VERIFY(p->p_proc_flag & P_PR_LOCK);
@@ -317,7 +406,7 @@ prreadenvv(proc_t *p, char *buf, size_t bufsz, size_t *slen)
 	/*
 	 * Extract the env array from the target process.
 	 */
-	if ((error = prreadbuf(p, up->u_envp, (uint8_t *)envp, envpsz,
+	if ((error = prreadbuf(p, up->u_envp, (char *)envp, envpsz,
 	    NULL)) != 0) {
 		kmem_free(envp, envpsz);
 		mutex_enter(&p->p_lock);
@@ -379,7 +468,7 @@ retry:
 		 * Read string data for this env var.  Leave room
 		 * in the buffer for a final NUL terminator.
 		 */
-		if ((error = prreadbuf(p, ev, (uint8_t *)&buf[pos], trysz,
+		if ((error = prreadbuf(p, ev, (char *)&buf[pos], trysz,
 		    &rdsz)) != 0) {
 			/*
 			 * There was a problem reading this string
diff --git a/usr/src/uts/common/fs/proc/prdata.h b/usr/src/uts/common/fs/proc/prdata.h
index 706e3ad14d..0ed015b9a2 100644
--- a/usr/src/uts/common/fs/proc/prdata.h
+++ b/usr/src/uts/common/fs/proc/prdata.h
@@ -27,7 +27,7 @@
 /*	  All Rights Reserved	*/
 
 /*
- * Copyright 2018 Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  */
 
 #ifndef _SYS_PROC_PRDATA_H
@@ -124,6 +124,7 @@ typedef enum prnodetype {
 	PR_LDT,			/* /proc/<pid>/ldt			*/
 #endif
 	PR_ARGV,		/* /proc/<pid>/argv			*/
+	PR_CMDLINE,		/* /proc/<pid>/cmdline			*/
 	PR_USAGE,		/* /proc/<pid>/usage			*/
 	PR_LUSAGE,		/* /proc/<pid>/lusage			*/
 	PR_PAGEDATA,		/* /proc/<pid>/pagedata			*/
@@ -351,6 +352,7 @@ extern	void	pr_sethold(prnode_t *, sigset_t *);
 extern	void	pr_setfault(proc_t *, fltset_t *);
 extern	int	prusrio(proc_t *, enum uio_rw, struct uio *, int);
 extern	int	prreadargv(proc_t *, char *, size_t, size_t *);
+extern	int	prreadcmdline(proc_t *, char *, size_t, size_t *);
 extern	int	prreadenvv(proc_t *, char *, size_t, size_t *);
 extern	int	prwritectl(vnode_t *, struct uio *, cred_t *);
 extern	int	prlock(prnode_t *, int);
diff --git a/usr/src/uts/common/fs/proc/prvnops.c b/usr/src/uts/common/fs/proc/prvnops.c
index 657cebf8c2..a9d9fe89ec 100644
--- a/usr/src/uts/common/fs/proc/prvnops.c
+++ b/usr/src/uts/common/fs/proc/prvnops.c
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2018, Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  * Copyright (c) 2017 by Delphix. All rights reserved.
  */
 
@@ -98,11 +98,6 @@ struct prdirect {
 #define	PRSDSIZE	(sizeof (struct prdirect))
 
 /*
- * Maximum length of the /proc/$$/argv file:
- */
-int prmaxargvlen = 4096;
-
-/*
  * Directory characteristics.
  */
 typedef struct prdirent {
@@ -171,12 +166,14 @@ static prdirent_t piddir[] = {
 		"contracts" },
 	{ PR_SECFLAGS,	27 * sizeof (prdirent_t), sizeof (prdirent_t),
 		"secflags" },
+	{ PR_ARGV,	28 * sizeof (prdirent_t), sizeof (prdirent_t),
+		"argv" },
+	{ PR_CMDLINE,	29 * sizeof (prdirent_t), sizeof (prdirent_t),
+		"cmdline" },
 #if defined(__x86)
-	{ PR_LDT,	28 * sizeof (prdirent_t), sizeof (prdirent_t),
+	{ PR_LDT,	30 * sizeof (prdirent_t), sizeof (prdirent_t),
 		"ldt" },
 #endif
-	{ PR_ARGV,	28 * sizeof (prdirent_t), sizeof (prdirent_t),
-		"argv" },
 };
 
 #define	NPIDDIRFILES	(sizeof (piddir) / sizeof (piddir[0]) - 2)
@@ -595,7 +592,7 @@ static int pr_read_inval(), pr_read_as(), pr_read_status(),
 #if defined(__x86)
 	pr_read_ldt(),
 #endif
-	pr_read_argv(),
+	pr_read_argv(), pr_read_cmdline(),
 	pr_read_usage(), pr_read_lusage(), pr_read_pagedata(),
 	pr_read_watch(), pr_read_lwpstatus(), pr_read_lwpsinfo(),
 	pr_read_lwpusage(), pr_read_lwpname(),
@@ -626,6 +623,7 @@ static int (*pr_read_function[PR_NFILES])() = {
 	pr_read_ldt,		/* /proc/<pid>/ldt			*/
 #endif
 	pr_read_argv,		/* /proc/<pid>/argv			*/
+	pr_read_cmdline,	/* /proc/<pid>/cmdline			*/
 	pr_read_usage,		/* /proc/<pid>/usage			*/
 	pr_read_lusage,		/* /proc/<pid>/lusage			*/
 	pr_read_pagedata,	/* /proc/<pid>/pagedata			*/
@@ -690,11 +688,46 @@ pr_uioread(void *base, long count, uio_t *uiop)
 }
 
 static int
+pr_read_cmdline(prnode_t *pnp, uio_t *uiop)
+{
+	char *args;
+	int error;
+	size_t asz = PRMAXARGVLEN, sz;
+
+	/*
+	 * Allocate a scratch buffer for collection of the process arguments.
+	 */
+	args = kmem_alloc(asz, KM_SLEEP);
+
+	ASSERT(pnp->pr_type == PR_CMDLINE);
+
+	if ((error = prlock(pnp, ZNO)) != 0) {
+		kmem_free(args, asz);
+		return (error);
+	}
+
+	if ((error = prreadcmdline(pnp->pr_common->prc_proc, args, asz,
+	    &sz)) != 0) {
+		prunlock(pnp);
+		kmem_free(args, asz);
+		return (error);
+	}
+
+	prunlock(pnp);
+
+	error = pr_uioread(args, sz, uiop);
+
+	kmem_free(args, asz);
+
+	return (error);
+}
+
+static int
 pr_read_argv(prnode_t *pnp, uio_t *uiop)
 {
 	char *args;
 	int error;
-	size_t asz = prmaxargvlen, sz;
+	size_t asz = PRMAXARGVLEN, sz;
 
 	/*
 	 * Allocate a scratch buffer for collection of the process arguments.
@@ -1872,6 +1905,7 @@ static int (*pr_read_function_32[PR_NFILES])() = {
 	pr_read_ldt,		/* /proc/<pid>/ldt			*/
 #endif
 	pr_read_argv,		/* /proc/<pid>/argv			*/
+	pr_read_cmdline,	/* /proc/<pid>/cmdline			*/
 	pr_read_usage_32,	/* /proc/<pid>/usage			*/
 	pr_read_lusage_32,	/* /proc/<pid>/lusage			*/
 	pr_read_pagedata_32,	/* /proc/<pid>/pagedata			*/
@@ -3317,7 +3351,7 @@ prgetattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 		if ((p->p_flag & SSYS) || p->p_as == &kas) {
 			vap->va_size = PSARGSZ;
 		} else {
-			vap->va_size = prmaxargvlen;
+			vap->va_size = PRMAXARGVLEN;
 		}
 		break;
 #if defined(__x86)
@@ -3442,6 +3476,7 @@ prgetattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 #endif
 	case PR_CTL:
 	case PR_LWPCTL:
+	case PR_CMDLINE:
 	default:
 		vap->va_size = 0;
 		break;
@@ -3497,6 +3532,7 @@ praccess(vnode_t *vp, int mode, int flags, cred_t *cr, caller_context_t *ct)
 	case PR_LUSAGE:
 	case PR_LWPUSAGE:
 	case PR_ARGV:
+	case PR_CMDLINE:
 		p = pr_p_lock(pnp);
 		mutex_exit(&pr_pidlock);
 		if (p == NULL)
@@ -3583,6 +3619,7 @@ static vnode_t *(*pr_lookup_function[PR_NFILES])() = {
 	pr_lookup_notdir,	/* /proc/<pid>/ldt			*/
 #endif
 	pr_lookup_notdir,	/* /proc/<pid>/argv			*/
+	pr_lookup_notdir,	/* /proc/<pid>/cmdline			*/
 	pr_lookup_notdir,	/* /proc/<pid>/usage			*/
 	pr_lookup_notdir,	/* /proc/<pid>/lusage			*/
 	pr_lookup_notdir,	/* /proc/<pid>/pagedata			*/
@@ -4871,6 +4908,7 @@ prgetnode(vnode_t *dp, prnodetype_t type)
 	case PR_LUSAGE:
 	case PR_LWPUSAGE:
 	case PR_ARGV:
+	case PR_CMDLINE:
 		pnp->pr_mode = 0444;	/* read-only by all */
 		break;
 
@@ -4977,6 +5015,7 @@ static int (*pr_readdir_function[PR_NFILES])() = {
 	pr_readdir_notdir,	/* /proc/<pid>/ldt			*/
 #endif
 	pr_readdir_notdir,	/* /proc/<pid>/argv			*/
+	pr_readdir_notdir,	/* /proc/<pid>/cmdline			*/
 	pr_readdir_notdir,	/* /proc/<pid>/usage			*/
 	pr_readdir_notdir,	/* /proc/<pid>/lusage			*/
 	pr_readdir_notdir,	/* /proc/<pid>/pagedata			*/
@@ -5129,6 +5168,7 @@ pr_readdir_piddir(prnode_t *pnp, uio_t *uiop, int *eofp)
 			case PR_PSINFO:
 			case PR_USAGE:
 			case PR_ARGV:
+			case PR_CMDLINE:
 				break;
 			default:
 				continue;
diff --git a/usr/src/uts/common/os/exec.c b/usr/src/uts/common/os/exec.c
index 24b6f0e2eb..62d1e298dd 100644
--- a/usr/src/uts/common/os/exec.c
+++ b/usr/src/uts/common/os/exec.c
@@ -24,7 +24,7 @@
  */
 
 /*	Copyright (c) 1988 AT&T	*/
-/*	  All Rights Reserved  	*/
+/*	All Rights Reserved	*/
 /*
  * Copyright 2019 Joyent, Inc.
  */
@@ -1712,7 +1712,9 @@ stk_copyin(execa_t *uap, uarg_t *args, intpdata_t *intp, void **auxvpp)
 		}
 	}
 	argc = (int *)(args->stk_base + args->stk_size) - args->stk_offp;
-	args->arglen = args->stk_strp - args->stk_base;
+	args->argstrlen = args->stk_strp - args->stk_base;
+
+	const char *envstr = args->stk_strp;
 
 	/*
 	 * Add environ[] strings to the stack.
@@ -1734,6 +1736,8 @@ stk_copyin(execa_t *uap, uarg_t *args, intpdata_t *intp, void **auxvpp)
 			envp += ptrsize;
 		}
 	}
+
+	args->envstrlen = args->stk_strp - envstr;
 	args->na = (int *)(args->stk_base + args->stk_size) - args->stk_offp;
 	args->ne = args->na - argc;
 
@@ -1823,46 +1827,53 @@ stk_copyout(uarg_t *args, char *usrstack, void **auxvpp, user_t *up)
 	 */
 	if (stk_putptr(args, usp, (char *)(uintptr_t)argc))
 		return (-1);
+	usp += ptrsize;
 
 	/*
-	 * Add argc space (ptrsize) to usp and record argv for /proc.
+	 * For the benefit of /proc, record the user address of the argv[] array
+	 * as well as the start of the argv string space (argv[0]).
 	 */
-	up->u_argv = (uintptr_t)(usp += ptrsize);
+	up->u_argv = (uintptr_t)usp;
+	up->u_argvstrs = (uintptr_t)(&ustrp[*(offp - 1)]);
+	up->u_argvstrsize = args->argstrlen;
 
 	/*
-	 * Put the argv[] pointers on the stack.
+	 * Put the argv[] pointers on the stack, including a NULL terminator.
 	 */
 	for (i = 0; i < argc; i++, usp += ptrsize)
 		if (stk_putptr(args, usp, &ustrp[*--offp]))
 			return (-1);
+	usp += ptrsize;
 
 	/*
 	 * Copy arguments to u_psargs.
 	 */
-	pslen = MIN(args->arglen, PSARGSZ) - 1;
+	pslen = MIN(args->argstrlen, PSARGSZ) - 1;
 	for (i = 0; i < pslen; i++)
 		up->u_psargs[i] = (kstrp[i] == '\0' ? ' ' : kstrp[i]);
 	while (i < PSARGSZ)
 		up->u_psargs[i++] = '\0';
 
 	/*
-	 * Add space for argv[]'s NULL terminator (ptrsize) to usp and
-	 * record envp for /proc.
+	 * For the benefit of /proc, record the user address of the envp[] array
+	 * as well as the start of the envp string space (envp[0]).
 	 */
-	up->u_envp = (uintptr_t)(usp += ptrsize);
+	up->u_envp = (uintptr_t)usp;
+	up->u_envstrs = (uintptr_t)(&ustrp[*(offp - 1)]);
+	up->u_envstrsize = args->envstrlen;
 
 	/*
-	 * Put the envp[] pointers on the stack.
+	 * Put the envp[] pointers on the stack, including a NULL terminator.
 	 */
 	for (i = 0; i < envc; i++, usp += ptrsize)
 		if (stk_putptr(args, usp, &ustrp[*--offp]))
 			return (-1);
+	usp += ptrsize;
 
 	/*
-	 * Add space for envp[]'s NULL terminator (ptrsize) to usp and
-	 * remember where the stack ends, which is also where auxv begins.
+	 * Remember where the stack ends, which is also where auxv begins.
 	 */
-	args->stackend = usp += ptrsize;
+	args->stackend = usp;
 
 	/*
 	 * Put all the argv[], envp[], and auxv strings on the stack.
@@ -2149,7 +2160,7 @@ exec_args(execa_t *uap, uarg_t *args, intpdata_t *intp, void **auxvpp)
 	delete_itimer_realprof();
 
 	if (AU_AUDITING())
-		audit_exec(args->stk_base, args->stk_base + args->arglen,
+		audit_exec(args->stk_base, args->stk_base + args->argstrlen,
 		    args->na - args->ne, args->ne, args->pfcred);
 
 	/*
diff --git a/usr/src/uts/common/os/zone.c b/usr/src/uts/common/os/zone.c
index 1db130797c..3d4e7ed7cd 100644
--- a/usr/src/uts/common/os/zone.c
+++ b/usr/src/uts/common/os/zone.c
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2019, Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  * Copyright (c) 2016 by Delphix. All rights reserved.
  * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
  */
@@ -4478,7 +4478,11 @@ zsched(void *arg)
 	bcopy("zsched", PTOU(pp)->u_comm, sizeof ("zsched"));
 	PTOU(pp)->u_argc = 0;
 	PTOU(pp)->u_argv = 0;
+	PTOU(pp)->u_argvstrs = 0;
+	PTOU(pp)->u_argvstrsize = 0;
 	PTOU(pp)->u_envp = 0;
+	PTOU(pp)->u_envstrs = 0;
+	PTOU(pp)->u_envstrsize = 0;
 	PTOU(pp)->u_commpagep = 0;
 	closeall(P_FINFO(pp));
 
diff --git a/usr/src/uts/common/sys/exec.h b/usr/src/uts/common/sys/exec.h
index 12115b7e27..d66a8dc15d 100644
--- a/usr/src/uts/common/sys/exec.h
+++ b/usr/src/uts/common/sys/exec.h
@@ -80,7 +80,8 @@ typedef struct uarg {
 	ssize_t	na;
 	ssize_t	ne;
 	ssize_t	nc;
-	ssize_t arglen;
+	size_t	argstrlen;
+	size_t	envstrlen;
 	char	*fname;
 	char	*pathname;
 	size_t	auxsize;
diff --git a/usr/src/uts/common/sys/procfs.h b/usr/src/uts/common/sys/procfs.h
index 99da92ab79..b24b2d9da1 100644
--- a/usr/src/uts/common/sys/procfs.h
+++ b/usr/src/uts/common/sys/procfs.h
@@ -25,7 +25,7 @@
  */
 /*
  * Copyright 2012 DEY Storage Systems, Inc.  All rights reserved.
- * Copyright 2018 Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  */
 
 #ifndef _SYS_PROCFS_H
@@ -271,10 +271,12 @@ typedef struct lwpsinfo {
 	int	pr_filler[4];	/* reserved for future use */
 } lwpsinfo_t;
 
+#define	PRARGSZ		80	/* number of chars of arguments */
+#define	PRMAXARGVLEN	4096	/* max len of /proc/%s/argv */
+
 /*
  * process ps(1) information file.  /proc/<pid>/psinfo
  */
-#define	PRARGSZ		80	/* number of chars of arguments */
 typedef struct psinfo {
 	int	pr_flag;	/* process flags (DEPRECATED; do not use) */
 	int	pr_nlwp;	/* number of active lwps in the process */
diff --git a/usr/src/uts/common/sys/user.h b/usr/src/uts/common/sys/user.h
index 15b4d0b247..8c424e7bf3 100644
--- a/usr/src/uts/common/sys/user.h
+++ b/usr/src/uts/common/sys/user.h
@@ -26,7 +26,7 @@
 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
 /*	  All Rights Reserved	*/
 /*
- * Copyright (c) 2018, Joyent, Inc.
+ * Copyright 2019 Joyent, Inc.
  */
 
 
@@ -227,7 +227,11 @@ typedef	struct	user {
 	char	u_psargs[PSARGSZ];	/* arguments from exec */
 	int	u_argc;			/* value of argc passed to main() */
 	uintptr_t u_argv;		/* value of argv passed to main() */
+	uintptr_t u_argvstrs;		/* argv string space pointer */
+	size_t u_argvstrsize;		/* size of argv string space */
 	uintptr_t u_envp;		/* value of envp passed to main() */
+	uintptr_t u_envstrs;		/* env string space pointer */
+	size_t u_envstrsize;		/* size of env string space */
 	uintptr_t u_commpagep;		/* address of mapped comm page */
 
 	/*