/*
* lslocks(8) - list local system locks
*
* Copyright (C) 2012 Davidlohr Bueso <dave@gnu.org>
*
* Very generally based on lslk(8) by Victor A. Abell <abe@purdue.edu>
* Since it stopped being maingained over a decade ago, this
* program should be considered its replacement.
*
* 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 <libmount.h>
#include <libsmartcols.h>
#include "pathnames.h"
#include "canonicalize.h"
#include "nls.h"
#include "xalloc.h"
#include "at.h"
#include "strutils.h"
#include "c.h"
#include "list.h"
#include "closestream.h"
/* column IDs */
enum {
COL_SRC = 0,
COL_PID,
COL_TYPE,
COL_SIZE,
COL_MODE,
COL_M,
COL_START,
COL_END,
COL_PATH,
COL_BLOCKER
};
/* 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_SRC] = { "COMMAND",15, 0, N_("command of the process holding the lock") },
[COL_PID] = { "PID", 5, SCOLS_FL_RIGHT, N_("PID of the process holding the lock") },
[COL_TYPE] = { "TYPE", 5, SCOLS_FL_RIGHT, N_("kind of lock: FL_FLOCK or FL_POSIX.") },
[COL_SIZE] = { "SIZE", 4, SCOLS_FL_RIGHT, N_("size of the lock") },
[COL_MODE] = { "MODE", 5, 0, N_("lock access mode") },
[COL_M] = { "M", 1, 0, N_("mandatory state of the lock: 0 (none), 1 (set)")},
[COL_START] = { "START", 10, SCOLS_FL_RIGHT, N_("relative byte offset of the lock")},
[COL_END] = { "END", 10, SCOLS_FL_RIGHT, N_("ending offset of the lock")},
[COL_PATH] = { "PATH", 0, SCOLS_FL_TRUNC, N_("path of the locked file")},
[COL_BLOCKER] = { "BLOCKER", 0, SCOLS_FL_RIGHT, N_("PID of the process blocking the lock") }
};
static int columns[ARRAY_SIZE(infos) * 2];
static int ncolumns;
static pid_t pid = 0;
static struct libmnt_table *tab; /* /proc/self/mountinfo */
/* basic output flags */
static int no_headings;
static int raw;
struct lock {
struct list_head locks;
char *cmdname;
pid_t pid;
char *path;
char *type;
char *mode;
off_t start;
off_t end;
unsigned int mandatory :1,
blocked :1;
char *size;
int id;
};
static void disable_columns_truncate(void)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(infos); i++)
infos[i].flags &= ~SCOLS_FL_TRUNC;
}
/*
* Return a PID's command name
*/
static char *get_cmdname(pid_t id)
{
FILE *fp;
char path[PATH_MAX], *ret = NULL;
sprintf(path, "/proc/%d/comm", id);
if (!(fp = fopen(path, "r")))
return NULL;
if (!fgets(path, sizeof(path), fp))
goto out;
path[strlen(path) - 1] = '\0';
ret = xstrdup(path);
out:
fclose(fp);
return ret;
}
/*
* Associate the device's mountpoint for a filename
*/
static char *get_fallback_filename(dev_t dev)
{
struct libmnt_fs *fs;
if (!tab) {
tab = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO);
if (!tab)
return NULL;
}
fs = mnt_table_find_devno(tab, dev, MNT_ITER_BACKWARD);
if (!fs)
return NULL;
return xstrdup(mnt_fs_get_target(fs));
}
/*
* Return the absolute path of a file from
* a given inode number (and its size)
*/
static char *get_filename_sz(ino_t inode, pid_t lock_pid, size_t *size)
{
struct stat sb;
struct dirent *dp;
DIR *dirp;
size_t len;
int fd;
char path[PATH_MAX], sym[PATH_MAX], *ret = NULL;
*size = 0;
memset(path, 0, sizeof(path));
memset(sym, 0, sizeof(sym));
/*
* We know the pid so we don't have to
* iterate the *entire* filesystem searching
* for the damn file.
*/
sprintf(path, "/proc/%d/fd/", lock_pid);
if (!(dirp = opendir(path)))
return NULL;
if ((len = strlen(path)) >= (sizeof(path) - 2))
goto out;
if ((fd = dirfd(dirp)) < 0 )
goto out;
while ((dp = readdir(dirp))) {
if (!strcmp(dp->d_name, ".") ||
!strcmp(dp->d_name, ".."))
continue;
/* care only for numerical descriptors */
if (!strtol(dp->d_name, (char **) NULL, 10))
continue;
if (!fstat_at(fd, path, dp->d_name, &sb, 0)
&& inode != sb.st_ino)
continue;
if ((len = readlink_at(fd, path, dp->d_name,
sym, sizeof(sym) - 1)) < 1)
goto out;
*size = sb.st_size;
sym[len] = '\0';
ret = xstrdup(sym);
break;
}
out:
closedir(dirp);
return ret;
}
/*
* Return the inode number from a string
*/
static ino_t get_dev_inode(char *str, dev_t *dev)
{
unsigned int maj = 0, min = 0;
ino_t inum = 0;
sscanf(str, "%02x:%02x:%ju", &maj, &min, &inum);
*dev = (dev_t) makedev(maj, min);
return inum;
}
static int get_local_locks(struct list_head *locks)
{
int i;
ino_t inode = 0;
FILE *fp;
char buf[PATH_MAX], *szstr = NULL, *tok = NULL;
size_t sz;
struct lock *l;
dev_t dev = 0;
if (!(fp = fopen(_PATH_PROC_LOCKS, "r")))
return -1;
while (fgets(buf, sizeof(buf), fp)) {
l = xcalloc(1, sizeof(*l));
INIT_LIST_HEAD(&l->locks);
for (tok = strtok(buf, " "), i = 0; tok;
tok = strtok(NULL, " "), i++) {
/*
* /proc/locks has *exactly* 8 "blocks" of text
* separated by ' ' - check <kernel>/fs/locks.c
*/
switch (i) {
case 0: /* ID: */
tok[strlen(tok) - 1] = '\0';
l->id = strtos32_or_err(tok, _("failed to parse ID"));
break;
case 1: /* posix, flock, etc */
if (strcmp(tok, "->") == 0) { /* optional field */
l->blocked = 1;
i--;
} else
l->type = xstrdup(tok);
break;
case 2: /* is this a mandatory lock? other values are advisory or noinode */
l->mandatory = *tok == 'M' ? 1 : 0;
break;
case 3: /* lock mode */
l->mode = xstrdup(tok);
break;
case 4: /* PID */
/*
* If user passed a pid we filter it later when adding
* to the list, no need to worry now.
*/
l->pid = strtos32_or_err(tok, _("failed to parse pid"));
l->cmdname = get_cmdname(l->pid);
if (!l->cmdname)
l->cmdname = xstrdup(_("(unknown)"));
break;
case 5: /* device major:minor and inode number */
inode = get_dev_inode(tok, &dev);
break;
case 6: /* start */
l->start = !strcmp(tok, "EOF") ? 0 :
strtou64_or_err(tok, _("failed to parse start"));
break;
case 7: /* end */
/* replace '\n' character */
tok[strlen(tok)-1] = '\0';
l->end = !strcmp(tok, "EOF") ? 0 :
strtou64_or_err(tok, _("failed to parse end"));
break;
default:
break;
}
l->path = get_filename_sz(inode, l->pid, &sz);
if (!l->path)
/* probably no permission to peek into l->pid's path */
l->path = get_fallback_filename(dev);
/* avoid leaking */
szstr = size_to_human_string(SIZE_SUFFIX_1LETTER, sz);
l->size = xstrdup(szstr);
free(szstr);
}
list_add(&l->locks, locks);
}
fclose(fp);
return 0;
}
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 < 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 void rem_lock(struct lock *lock)
{
if (!lock)
return;
free(lock->path);
free(lock->size);
free(lock->mode);
free(lock->cmdname);
free(lock->type);
list_del(&lock->locks);
free(lock);
}
static pid_t get_blocker(int id, struct list_head *locks)
{
struct list_head *p;
list_for_each(p, locks) {
struct lock *l = list_entry(p, struct lock, locks);
if (l->id == id && !l->blocked)
return l->pid;
}
return 0;
}
static void add_scols_line(struct libscols_table *table, struct lock *l, struct list_head *locks)
{
int i;
struct libscols_line *line;
/*
* Whenever cmdname or filename is NULL it is most
* likely because there's no read permissions
* for the specified process.
*/
const char *notfnd = "";
assert(l);
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_SRC:
xasprintf(&str, "%s", l->cmdname ? l->cmdname : notfnd);
break;
case COL_PID:
xasprintf(&str, "%d", l->pid);
break;
case COL_TYPE:
xasprintf(&str, "%s", l->type);
break;
case COL_SIZE:
xasprintf(&str, "%s", l->size);
break;
case COL_MODE:
xasprintf(&str, "%s%s", l->mode, l->blocked ? "*" : "");
break;
case COL_M:
xasprintf(&str, "%d", l->mandatory ? 1 : 0);
break;
case COL_START:
xasprintf(&str, "%jd", l->start);
break;
case COL_END:
xasprintf(&str, "%jd", l->end);
break;
case COL_PATH:
xasprintf(&str, "%s", l->path ? l->path : notfnd);
break;
case COL_BLOCKER:
{
pid_t bl = l->blocked && l->id ?
get_blocker(l->id, locks) : 0;
if (bl)
xasprintf(&str, "%d", (int) bl);
}
default:
break;
}
if (str)
scols_line_set_data(line, i, str);
}
}
static int show_locks(struct list_head *locks)
{
int i, rc = 0;
struct list_head *p, *pnext;
struct libscols_table *table;
table = scols_new_table();
if (!table) {
warn(_("failed to initialize output table"));
return -1;
}
scols_table_enable_raw(table, raw);
scols_table_enable_noheadings(table, no_headings);
for (i = 0; i < ncolumns; i++) {
struct colinfo *col = get_column_info(i);
if (!scols_table_new_column(table, col->name, col->whint, col->flags)) {
warnx(_("failed to initialize output column"));
rc = -1;
goto done;
}
}
/* prepare data for output */
list_for_each(p, locks) {
struct lock *l = list_entry(p, struct lock, locks);
if (pid && pid != l->pid)
continue;
add_scols_line(table, l, locks);
}
/* destroy the list */
list_for_each_safe(p, pnext, locks) {
struct lock *l = list_entry(p, struct lock, locks);
rem_lock(l);
}
scols_print_table(table);
done:
scols_unref_table(table);
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(_(" -p, --pid <pid> process id\n"
" -o, --output <list> define which output columns to use\n"
" -n, --noheadings don't print headings\n"
" -r, --raw use the raw output format\n"
" -u, --notruncate don't truncate text in columns\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"), 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[])
{
int c, rc = 0;
struct list_head locks;
char *outarg = NULL;
static const struct option long_opts[] = {
{ "pid", 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 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv,
"p:o:nruhV", long_opts, NULL)) != -1) {
switch(c) {
case 'p':
pid = strtos32_or_err(optarg, _("invalid PID argument"));
break;
case 'o':
outarg = optarg;
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'h':
usage(stdout);
case 'n':
no_headings = 1;
break;
case 'r':
raw = 1;
break;
case 'u':
disable_columns_truncate();
break;
case '?':
default:
usage(stderr);
}
}
INIT_LIST_HEAD(&locks);
if (!ncolumns) {
/* default columns */
columns[ncolumns++] = COL_SRC;
columns[ncolumns++] = COL_PID;
columns[ncolumns++] = COL_TYPE;
columns[ncolumns++] = COL_SIZE;
columns[ncolumns++] = COL_MODE;
columns[ncolumns++] = COL_M;
columns[ncolumns++] = COL_START;
columns[ncolumns++] = COL_END;
columns[ncolumns++] = COL_PATH;
}
if (outarg && string_add_to_idarray(outarg, columns, ARRAY_SIZE(columns),
&ncolumns, column_name_to_id) < 0)
return EXIT_FAILURE;
scols_init_debug(0);
rc = get_local_locks(&locks);
if (!rc && !list_empty(&locks))
rc = show_locks(&locks);
mnt_unref_table(tab);
return rc;
}
