MFC r295856 (by des@):

Implement /proc/$$/limits.

MFC r297781 (by dchagin@):
More complete implementation of /proc/self/limits.
Fix the way the code accesses process limits struct - pointed out by mjg@.

MFC r298318, 298319 (by cem@):
Don't print uninitialized values and initialize error return before use.

PR:		207386

2 files changed, 101 insertions, 0 deletions

diff --git a/sys/compat/linprocfs/linprocfs.c b/sys/compat/linprocfs/linprocfs.c
index 8aac3ea..bf0610b 100644
--- a/sys/compat/linprocfs/linprocfs.c
+++ b/sys/compat/linprocfs/linprocfs.c
@@ -63,6 +63,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/ptrace.h>
 #include <sys/resourcevar.h>
+#include <sys/resource.h>
 #include <sys/sbuf.h>
 #include <sys/sem.h>
 #include <sys/smp.h>
@@ -1350,6 +1351,97 @@ linprocfs_dofdescfs(PFS_FILL_ARGS)
 	return (0);
 }
 
+/*
+ * Filler function for proc/pid/limits
+ */
+static const struct linux_rlimit_ident {
+	const char	*desc;
+	const char	*unit;
+	unsigned int	rlim_id;
+} linux_rlimits_ident[] = {
+	{ "Max cpu time",	"seconds",	RLIMIT_CPU },
+	{ "Max file size", 	"bytes",	RLIMIT_FSIZE },
+	{ "Max data size",	"bytes", 	RLIMIT_DATA },
+	{ "Max stack size",	"bytes", 	RLIMIT_STACK },
+	{ "Max core file size",  "bytes",	RLIMIT_CORE },
+	{ "Max resident set",	"bytes",	RLIMIT_RSS },
+	{ "Max processes",	"processes",	RLIMIT_NPROC },
+	{ "Max open files",	"files",	RLIMIT_NOFILE },
+	{ "Max locked memory",	"bytes",	RLIMIT_MEMLOCK },
+	{ "Max address space",	"bytes",	RLIMIT_AS },
+	{ "Max file locks",	"locks",	LINUX_RLIMIT_LOCKS },
+	{ "Max pending signals", "signals",	LINUX_RLIMIT_SIGPENDING },
+	{ "Max msgqueue size",	"bytes",	LINUX_RLIMIT_MSGQUEUE },
+	{ "Max nice priority", 		"",	LINUX_RLIMIT_NICE },
+	{ "Max realtime priority",	"",	LINUX_RLIMIT_RTPRIO },
+	{ "Max realtime timeout",	"us",	LINUX_RLIMIT_RTTIME },
+	{ 0, 0, 0 }
+};
+
+static int
+linprocfs_doproclimits(PFS_FILL_ARGS)
+{
+	const struct linux_rlimit_ident *li;
+	struct plimit *limp;
+	struct rlimit rl;
+	ssize_t size;
+	int res, error;
+
+	error = 0;
+
+	PROC_LOCK(p);
+	limp = lim_hold(p->p_limit);
+	PROC_UNLOCK(p);
+	size = sizeof(res);
+	sbuf_printf(sb, "%-26s%-21s%-21s%-21s\n", "Limit", "Soft Limit",
+			"Hard Limit", "Units");
+	for (li = linux_rlimits_ident; li->desc != NULL; ++li) {
+		switch (li->rlim_id)
+		{
+		case LINUX_RLIMIT_LOCKS:
+			/* FALLTHROUGH */
+		case LINUX_RLIMIT_RTTIME:
+			rl.rlim_cur = RLIM_INFINITY;
+			break;
+		case LINUX_RLIMIT_SIGPENDING:
+			error = kernel_sysctlbyname(td,
+			    "kern.sigqueue.max_pending_per_proc",
+			    &res, &size, 0, 0, 0, 0);
+			if (error != 0)
+				goto out;
+			rl.rlim_cur = res;
+			rl.rlim_max = res;
+			break;
+		case LINUX_RLIMIT_MSGQUEUE:
+			error = kernel_sysctlbyname(td,
+			    "kern.ipc.msgmnb", &res, &size, 0, 0, 0, 0);
+			if (error != 0)
+				goto out;
+			rl.rlim_cur = res;
+			rl.rlim_max = res;
+			break;
+		case LINUX_RLIMIT_NICE:
+			/* FALLTHROUGH */
+		case LINUX_RLIMIT_RTPRIO:
+			rl.rlim_cur = 0;
+			rl.rlim_max = 0;
+			break;
+		default:
+			rl = limp->pl_rlimit[li->rlim_id];
+			break;
+		}
+		if (rl.rlim_cur == RLIM_INFINITY)
+			sbuf_printf(sb, "%-26s%-21s%-21s%-10s\n",
+			    li->desc, "unlimited", "unlimited", li->unit);
+		else
+			sbuf_printf(sb, "%-26s%-21llu%-21llu%-10s\n",
+			    li->desc, (unsigned long long)rl.rlim_cur,
+			    (unsigned long long)rl.rlim_max, li->unit);
+	}
+out:
+	lim_free(limp);
+	return (error);
+}
 
 /*
  * Filler function for proc/sys/kernel/random/uuid
@@ -1488,6 +1580,8 @@ linprocfs_init(PFS_INIT_ARGS)
 	    NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "auxv", &linprocfs_doauxv,
 	    NULL, &procfs_candebug, NULL, PFS_RD|PFS_RAWRD);
+	pfs_create_file(dir, "limits", &linprocfs_doproclimits,
+	    NULL, NULL, NULL, PFS_RD);
 
 	/* /proc/scsi/... */
 	dir = pfs_create_dir(root, "scsi", NULL, NULL, NULL, 0);
diff --git a/sys/compat/linux/linux_misc.h b/sys/compat/linux/linux_misc.h
index f969c4d..d140c67 100644
--- a/sys/compat/linux/linux_misc.h
+++ b/sys/compat/linux/linux_misc.h
@@ -141,6 +141,13 @@ extern int stclohz;
 #define	LINUX_P_PID		1
 #define	LINUX_P_PGID		2
 
+#define	LINUX_RLIMIT_LOCKS	RLIM_NLIMITS + 1
+#define	LINUX_RLIMIT_SIGPENDING	RLIM_NLIMITS + 2
+#define	LINUX_RLIMIT_MSGQUEUE	RLIM_NLIMITS + 3
+#define	LINUX_RLIMIT_NICE	RLIM_NLIMITS + 4
+#define	LINUX_RLIMIT_RTPRIO	RLIM_NLIMITS + 5
+#define	LINUX_RLIMIT_RTTIME	RLIM_NLIMITS + 6
+
 #define	LINUX_RLIM_INFINITY	(~0UL)
 
 int linux_common_wait(struct thread *td, int pid, int *status,