3294 pfiles postmortem support

Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Eric Schrock <eric.schrock@delphix.com>

1 files changed, 168 insertions, 0 deletions

diff --git a/usr/src/lib/libproc/common/Pfdinfo.c b/usr/src/lib/libproc/common/Pfdinfo.c
new file mode 100644
index 0000000000..0d41b5606d
--- /dev/null
+++ b/usr/src/lib/libproc/common/Pfdinfo.c
@@ -0,0 +1,168 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+
+/*
+ * Copyright 2012 DEY Storage Systems, Inc.  All rights reserved.
+ */
+
+#include <limits.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <ctype.h>
+#include <string.h>
+#include <sys/mkdev.h>
+
+#include "libproc.h"
+#include "Pcontrol.h"
+
+/*
+ * Pfdinfo.c - obtain open file information.
+ */
+
+/*
+ * Allocate an fd_info structure and stick it on the list.
+ * (Unless one already exists.)  The list is sorted in
+ * reverse order.  We will traverse it in that order later.
+ * This makes the usual ordered insert *fast*.
+ */
+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);
+	}
+
+	for (i = 0; i < P->num_fd; i++, fip = list_next(fip)) {
+		if (fip->fd_info.pr_fd == fd) {
+			return (fip);
+		}
+		if (fip->fd_info.pr_fd < fd) {
+			break;
+		}
+	}
+
+	next = fip;
+	if ((fip = calloc(1, sizeof (*fip))) == NULL)
+		return (NULL);
+
+	fip->fd_info.pr_fd = fd;
+	list_link(fip, next ? next : (void *)&(P->fd_head));
+	P->num_fd++;
+	return (fip);
+}
+
+/*
+ * Attempt to load the open file information from a live process.
+ */
+static void
+load_fdinfo(struct ps_prochandle *P)
+{
+	/*
+	 * In the unlikely case there are *no* file descriptors open,
+	 * we will keep rescanning the proc directory, which will be empty.
+	 * This is an edge case it isn't worth adding additional state to
+	 * to eliminate.
+	 */
+	if (P->num_fd > 0) {
+		return;
+	}
+
+	if (P->state != PS_DEAD && P->state != PS_IDLE) {
+		char dir_name[PATH_MAX];
+		char path[PATH_MAX];
+		struct dirent *ent;
+		DIR	*dirp;
+		int	fd;
+
+		/*
+		 * Try to get the path information first.
+		 */
+		(void) snprintf(dir_name, sizeof (dir_name),
+		    "%s/%d/path", procfs_path, (int)P->pid);
+		dirp = opendir(dir_name);
+		if (dirp == NULL) {
+			return;
+		}
+		ent = NULL;
+		while ((ent = readdir(dirp)) != NULL) {
+			fd_info_t	*fip;
+			prfdinfo_t	*info;
+			int		len;
+			struct stat64	stat;
+
+			if (!isdigit(ent->d_name[0]))
+				continue;
+
+			fd = atoi(ent->d_name);
+
+			fip = Pfd2info(P, fd);
+			info = &fip->fd_info;
+			info->pr_fd = fd;
+
+			if (pr_fstat64(P, fd, &stat) == 0) {
+				info->pr_mode = stat.st_mode;
+				info->pr_uid = stat.st_uid;
+				info->pr_gid = stat.st_gid;
+				info->pr_major = major(stat.st_dev);
+				info->pr_minor = minor(stat.st_dev);
+				info->pr_rmajor = major(stat.st_rdev);
+				info->pr_rminor = minor(stat.st_rdev);
+				info->pr_size = stat.st_size;
+				info->pr_ino = stat.st_ino;
+			}
+
+			info->pr_fileflags = pr_fcntl(P, fd, F_GETXFL, 0);
+			info->pr_fdflags = pr_fcntl(P, fd, F_GETFD, 0);
+			info->pr_offset = pr_llseek(P, fd, 0, SEEK_CUR);
+
+			/* attempt to determine the path to it */
+			(void) snprintf(path, sizeof (path),
+			    "%s/%d/path/%d", procfs_path, (int)P->pid, fd);
+			len = readlink(path, info->pr_path,
+			    sizeof (info->pr_path) - 1);
+
+			if (len < 0) {
+				info->pr_path[0] = 0;
+			} else {
+				info->pr_path[len] = 0;
+			}
+		}
+		(void) closedir(dirp);
+
+	}
+}
+
+int
+Pfdinfo_iter(struct ps_prochandle *P, proc_fdinfo_f *func, void *cd)
+{
+	fd_info_t *fip;
+	int rv;
+
+	/* Make sure we have live data, if appropriate */
+	load_fdinfo(P);
+
+	/* NB: We walk the list backwards. */
+
+	for (fip = list_prev(&P->fd_head);
+	    fip != (void *)&P->fd_head;
+	    fip = list_prev(fip)) {
+		if ((rv = func(cd, &fip->fd_info)) != 0)
+			return (rv);
+	}
+	return (0);
+}