lsns: new command

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 572 insertions, 0 deletions

diff --git a/sys-utils/lsns.c b/sys-utils/lsns.c
new file mode 100644
index 000000000..6bc651292
--- /dev/null
+++ b/sys-utils/lsns.c
@@ -0,0 +1,572 @@
+/*
+ * lsns(8) - list system namespaces
+ *
+ * Copyright (C) 2015 Karel Zak <kzak@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include <stdio.h>
+#include <string.h>
+#include <getopt.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <libsmartcols.h>
+
+#include "pathnames.h"
+#include "nls.h"
+#include "xalloc.h"
+#include "c.h"
+#include "list.h"
+#include "closestream.h"
+#include "optutils.h"
+#include "procutils.h"
+#include "strutils.h"
+#include "namespace.h"
+#include "path.h"
+
+#include "debug.h"
+
+UL_DEBUG_DEFINE_MASK(lsns);
+UL_DEBUG_DEFINE_MASKNAMES(lsns) = UL_DEBUG_EMPTY_MASKNAMES;
+
+#define LSNS_DEBUG_INIT		(1 << 1)
+#define LSNS_DEBUG_PROC		(1 << 2)
+#define LSNS_DEBUG_NS		(1 << 3)
+#define LSNS_DEBUG_ALL		0xFFFF
+
+#define DBG(m, x)       __UL_DBG(lsns, LSNS_DEBUG_, m, x)
+#define ON_DBG(m, x)    __UL_DBG_CALL(lsns, LSNS_DEBUG_, m, x)
+
+/* column IDs */
+enum {
+	COL_NS = 0,
+	COL_TYPE,
+	COL_PATH,
+	COL_NPROCS,
+	COL_PID,
+	COL_COMMAND
+};
+
+/* column names */
+struct colinfo {
+	const char *name; /* header */
+	double	   whint; /* width hint (N < 1 is in percent of termwidth) */
+	int	   flags; /* SCOLS_FL_* */
+	const char *help;
+};
+
+/* columns descriptions */
+static struct colinfo infos[] = {
+	[COL_NS]      = { "NS",     10, SCOLS_FL_RIGHT, N_("command of the process holding the lock") },
+	[COL_TYPE]    = { "TYPE",    5, 0, N_("kind of namespace") },
+	[COL_PATH]    = { "PATH",    0, 0, N_("path to the namespace")},
+	[COL_NPROCS]  = { "NPROCS",  5, SCOLS_FL_RIGHT, N_("number of processes in the namespace") },
+	[COL_PID]     = { "PID",     5, SCOLS_FL_RIGHT, N_("lowers PID in the namespace") },
+	[COL_COMMAND] = { "COMMAND", 0, SCOLS_FL_TRUNC, N_("command line of the PID")}
+};
+
+static int columns[ARRAY_SIZE(infos) * 2];
+static size_t ncolumns;
+
+enum {
+	LSNS_ID_MNT = 0,
+	LSNS_ID_NET,
+	LSNS_ID_PID,
+	LSNS_ID_UTS,
+	LSNS_ID_IPC,
+	LSNS_ID_USER
+};
+
+static char *ns_names[] = {
+	[LSNS_ID_MNT] = "mnt",
+	[LSNS_ID_NET] = "net",
+	[LSNS_ID_PID] = "pid",
+	[LSNS_ID_UTS] = "uts",
+	[LSNS_ID_IPC] = "ipc",
+	[LSNS_ID_USER] = "user"
+};
+
+struct lsns_namespace {
+	ino_t id;
+	int type;			/* LSNS_* */
+	int nprocs;
+	pid_t pid;
+
+	struct list_head namespaces;	/* lsns->processes member */
+	struct list_head processes;	/* head of lsns_process *siblings */
+};
+
+struct lsns_process {
+	pid_t pid;		/* process PID */
+	pid_t ppid;		/* parent's PID */
+	pid_t tpid;		/* thread group */
+	char state;
+
+	ino_t            ns_ids[ARRAY_SIZE(ns_names)];
+	struct list_head ns_siblings[ARRAY_SIZE(ns_names)];
+
+	struct list_head branch;	/* head of children list */
+	struct list_head children;	/* list of children */
+	struct list_head processes;	/* list of processes */
+};
+
+struct lsns {
+	struct list_head processes;
+	struct list_head namespaces;
+
+	pid_t	pid;
+
+	unsigned int raw	: 1,
+		     json	: 1,
+		     no_headings: 1;
+};
+
+static void lsns_init_debug(void)
+{
+	__UL_INIT_DEBUG(lsns, LSNS_DEBUG_, 0, LSNS_DEBUG);
+}
+
+static void disable_columns_truncate(void)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(infos); i++)
+		infos[i].flags &= ~SCOLS_FL_TRUNC;
+}
+
+static int column_name_to_id(const char *name, size_t namesz)
+{
+	size_t i;
+
+	assert(name);
+
+	for (i = 0; i < ARRAY_SIZE(infos); i++) {
+		const char *cn = infos[i].name;
+
+		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+			return i;
+	}
+	warnx(_("unknown column: %s"), name);
+	return -1;
+}
+
+static inline int get_column_id(int num)
+{
+	assert(num >= 0);
+	assert((size_t) num < ncolumns);
+	assert(columns[num] < (int) ARRAY_SIZE(infos));
+
+	return columns[num];
+}
+
+static inline struct colinfo *get_column_info(unsigned num)
+{
+	return &infos[ get_column_id(num) ];
+}
+
+static ino_t get_ns_ino(int dir, const char *nsname, ino_t *ino)
+{
+	struct stat st;
+	char path[16];
+
+	snprintf(path, sizeof(path), "ns/%s", nsname);
+
+	if (fstatat(dir, path, &st, 0) != 0)
+		return -errno;
+	*ino = st.st_ino;
+	return 0;
+}
+
+static int read_process(struct lsns *ls, pid_t pid)
+{
+	struct lsns_process *p = NULL;
+	char buf[BUFSIZ];
+	DIR *dir;
+	int rc = 0, fd;
+	FILE *f = NULL;
+	size_t i;
+
+	DBG(PROC, ul_debug("reading %d", (int) pid));
+
+	snprintf(buf, sizeof(buf), "/proc/%d", pid);
+	dir = opendir(buf);
+	if (!dir)
+		return -errno;
+
+	p = calloc(1, sizeof(*p));
+	if (!p) {
+		rc = -ENOMEM;
+		goto done;
+	}
+
+	fd = openat(dirfd(dir), "stat", O_RDONLY);
+	if (fd < 0) {
+		rc = -errno;
+		goto done;
+	}
+	if (!(f = fdopen(fd, "r"))) {
+		rc = -errno;
+		goto done;
+	}
+	rc = fscanf(f, "%d %*s %c %d*[^\n]", &p->pid, &p->state, &p->ppid);
+	if (rc != 3) {
+		rc = -errno;
+		goto done;
+	}
+	rc = 0;
+
+	for (i = 0; i < ARRAY_SIZE(p->ns_ids); i++) {
+		INIT_LIST_HEAD(&p->ns_siblings[i]);
+
+		rc = get_ns_ino(dirfd(dir), ns_names[i], &p->ns_ids[i]);
+		if (rc && rc != -EACCES)
+			goto done;
+		rc = 0;
+	}
+
+	INIT_LIST_HEAD(&p->processes);
+	INIT_LIST_HEAD(&p->branch);
+	INIT_LIST_HEAD(&p->children);
+
+	DBG(PROC, ul_debug("add %d", p->pid));
+	list_add_tail(&p->processes, &ls->processes);
+done:
+	if (f)
+		fclose(f);
+	closedir(dir);
+	if (rc)
+		free(p);
+	return rc;
+}
+
+static int read_processes(struct lsns *ls)
+{
+	struct proc_processes *proc = NULL;
+	pid_t pid;
+	int rc = 0;
+
+	if (ls->pid) {
+		rc = read_process(ls, ls->pid);
+		goto done;
+	}
+
+	DBG(PROC, ul_debug("opening /proc"));
+
+	if (!(proc = proc_open_processes())) {
+		rc = -errno;
+		goto done;
+	}
+
+	while (proc_next_pid(proc, &pid) == 0) {
+		rc = read_process(ls, pid);
+		if (rc && rc != -EACCES)
+			break;
+		rc = 0;
+	}
+done:
+	DBG(PROC, ul_debug("closing /proc"));
+	proc_close_processes(proc);
+	return rc;
+}
+
+static struct lsns_namespace *get_namespace(struct lsns *ls, int type, ino_t ino)
+{
+	struct list_head *p;
+
+	list_for_each(p, &ls->namespaces) {
+		struct lsns_namespace *ns = list_entry(p, struct lsns_namespace, namespaces);
+
+		if (ns->id == ino && ns->type == type)
+			return ns;
+	}
+	return NULL;
+}
+
+static struct lsns_namespace *add_namespace(struct lsns *ls, int type, ino_t ino)
+{
+	struct lsns_namespace *ns = calloc(1, sizeof(*ns));
+
+	if (!ns)
+		return NULL;
+
+	DBG(NS, ul_debug("add %s[%lu]", ns_names[type], ino));
+
+	INIT_LIST_HEAD(&ns->processes);
+	INIT_LIST_HEAD(&ns->namespaces);
+
+	ns->type = type;
+	ns->id = ino;
+
+	list_add_tail(&ns->namespaces, &ls->namespaces);
+	return ns;
+}
+
+static int add_process_to_namespace(struct lsns_namespace *ns, struct lsns_process *proc)
+{
+	DBG(NS, ul_debug("add process %d to %s[%lu]", proc->pid, ns_names[ns->type], ns->id));
+
+	list_add_tail(&proc->ns_siblings[ns->type], &ns->processes);
+	ns->nprocs++;
+
+	if (ns->pid == 0 || ns->pid > proc->pid)
+		ns->pid = proc->pid;
+	return 0;
+}
+
+static int read_namespaces(struct lsns *ls)
+{
+	struct list_head *p;
+
+	DBG(NS, ul_debug("reading namespace"));
+
+	list_for_each(p, &ls->processes) {
+		size_t i;
+		struct lsns_namespace *ns;
+		struct lsns_process *proc = list_entry(p, struct lsns_process, processes);
+
+		for (i = 0; i < ARRAY_SIZE(proc->ns_ids); i++) {
+			if (proc->ns_ids[i] == 0)
+				continue;
+			if (!(ns = get_namespace(ls, i, proc->ns_ids[i]))) {
+				ns = add_namespace(ls, i, proc->ns_ids[i]);
+				if (!ns)
+					return -ENOMEM;
+			}
+			add_process_to_namespace(ns, proc);
+		}
+	}
+
+	return 0;
+}
+
+static void add_scols_line(struct libscols_table *table, struct lsns_namespace *ns)
+{
+	size_t i;
+	struct libscols_line *line;
+
+	assert(ns);
+	assert(table);
+
+	line = scols_table_new_line(table, NULL);
+	if (!line) {
+		warn(_("failed to add line to output"));
+		return;
+	}
+
+	for (i = 0; i < ncolumns; i++) {
+		char *str = NULL;
+
+		switch (get_column_id(i)) {
+		case COL_NS:
+			xasprintf(&str, "%lu", ns->id);
+			break;
+		case COL_PID:
+			xasprintf(&str, "%d", (int) ns->pid);
+			break;
+		case COL_TYPE:
+			xasprintf(&str, "%s", ns_names[ns->type]);
+			break;
+		case COL_NPROCS:
+			xasprintf(&str, "%d", ns->nprocs);
+			break;
+		case COL_COMMAND:
+			str = proc_get_command(ns->pid);
+			if (!str)
+				str = proc_get_command_name(ns->pid);
+			break;
+		case COL_PATH:
+			break;
+		default:
+			break;
+		}
+
+		if (str)
+			scols_line_set_data(line, i, str);
+	}
+}
+
+static int show_namespaces(struct lsns *ls)
+{
+	struct libscols_table *tab;
+	struct list_head *p;
+	size_t i;
+	int rc = 0;
+
+	tab = scols_new_table();
+	if (!tab) {
+		warn(_("failed to initialize output table"));
+		return -ENOMEM;
+	}
+
+	scols_table_enable_raw(tab, ls->raw);
+	scols_table_enable_json(tab, ls->json);
+	scols_table_enable_noheadings(tab, ls->no_headings);
+
+	if (ls->json)
+		scols_table_set_name(tab, "namespaces");
+
+	for (i = 0; i < ncolumns; i++) {
+		struct colinfo *col = get_column_info(i);
+
+		if (!scols_table_new_column(tab, col->name, col->whint, col->flags)) {
+			warnx(_("failed to initialize output column"));
+			rc = -errno;
+			goto done;
+		}
+	}
+
+	list_for_each(p, &ls->namespaces) {
+		struct lsns_namespace *ns = list_entry(p, struct lsns_namespace, namespaces);
+		add_scols_line(tab, ns);
+	}
+
+	scols_print_table(tab);
+done:
+	scols_unref_table(tab);
+	return rc;
+}
+
+static void __attribute__ ((__noreturn__)) usage(FILE * out)
+{
+	size_t i;
+
+	fputs(USAGE_HEADER, out);
+
+	fprintf(out,
+		_(" %s [options]\n"), program_invocation_short_name);
+
+	fputs(USAGE_SEPARATOR, out);
+	fputs(_("List local system locks.\n"), out);
+
+	fputs(USAGE_OPTIONS, out);
+	fputs(_(" -J, --json             use JSON output format\n"), out);
+	fputs(_(" -p, --task <pid>       print process namespace\n"), out);
+	fputs(_(" -n, --noheadings       don't print headings\n"), out);
+	fputs(_(" -o, --output <list>    define which output columns to use\n"), out);
+	fputs(_(" -r, --raw              use the raw output format\n"), out);
+	fputs(_(" -u, --notruncate       don't truncate text in columns\n"), out);
+
+	fputs(USAGE_SEPARATOR, out);
+	fputs(USAGE_HELP, out);
+	fputs(USAGE_VERSION, out);
+
+	fputs(_("\nAvailable columns (for --output):\n"), out);
+
+	for (i = 0; i < ARRAY_SIZE(infos); i++)
+		fprintf(out, " %11s  %s\n", infos[i].name, _(infos[i].help));
+
+	fprintf(out, USAGE_MAN_TAIL("lslocks(8)"));
+
+	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+int main(int argc, char *argv[])
+{
+	struct lsns ls;
+	int c;
+	int r = 0;
+	char *outarg = NULL;
+	static const struct option long_opts[] = {
+		{ "json",       no_argument,       NULL, 'J' },
+		{ "task",       required_argument, NULL, 'p' },
+		{ "help",	no_argument,       NULL, 'h' },
+		{ "output",     required_argument, NULL, 'o' },
+		{ "notruncate", no_argument,       NULL, 'u' },
+		{ "version",    no_argument,       NULL, 'V' },
+		{ "noheadings", no_argument,       NULL, 'n' },
+		{ "raw",        no_argument,       NULL, 'r' },
+		{ NULL, 0, NULL, 0 }
+	};
+
+	static const ul_excl_t excl[] = {	/* rows and cols in ASCII order */
+		{ 'J','r' },
+		{ 0 }
+	};
+	int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+	atexit(close_stdout);
+
+	lsns_init_debug();
+
+	memset(&ls, 0, sizeof(ls));
+	INIT_LIST_HEAD(&ls.processes);
+	INIT_LIST_HEAD(&ls.namespaces);
+
+	while ((c = getopt_long(argc, argv,
+				"Jp:o:nruhV", long_opts, NULL)) != -1) {
+
+		err_exclusive_options(c, long_opts, excl, excl_st);
+
+		switch(c) {
+		case 'J':
+			ls.json = 1;
+			break;
+		case 'o':
+			outarg = optarg;
+			break;
+		case 'V':
+			printf(UTIL_LINUX_VERSION);
+			return EXIT_SUCCESS;
+		case 'p':
+			ls.pid = strtos32_or_err(optarg, _("invalid PID argument"));
+			break;
+		case 'h':
+			usage(stdout);
+		case 'n':
+			ls.no_headings = 1;
+			break;
+		case 'r':
+			ls.raw = 1;
+			break;
+		case 'u':
+			disable_columns_truncate();
+			break;
+		case '?':
+		default:
+			usage(stderr);
+		}
+	}
+
+	if (!ncolumns) {
+		/* default columns */
+		columns[ncolumns++] = COL_NS;
+		columns[ncolumns++] = COL_TYPE;
+		columns[ncolumns++] = COL_NPROCS;
+		columns[ncolumns++] = COL_PID;
+		columns[ncolumns++] = COL_COMMAND;
+	}
+
+	if (outarg && string_add_to_idarray(outarg, columns, ARRAY_SIZE(columns),
+					 &ncolumns, column_name_to_id) < 0)
+		return EXIT_FAILURE;
+
+	scols_init_debug(0);
+
+	r = read_processes(&ls);
+	if (!r)
+		r = read_namespaces(&ls);
+	if (!r)
+		r = show_namespaces(&ls);
+
+	return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}