lsfd: mark XMODE.m on fds monitored by poll(2) and ppoll(2)

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

diff --git a/misc-utils/lsfd.c b/misc-utils/lsfd.c
index fb52c86244b0040a8abdf9c0461f1fdae51a803b..ed23b6109c27cc4226eb5002a3b8ddda7183d711 100644 (file)
--- a/misc-utils/lsfd.c
+++ b/misc-utils/lsfd.c
@@ -31,7 +31,9 @@
 #include <getopt.h>
 #include <ctype.h>
 #include <search.h>
+#include <poll.h>
 
+#include <sys/uio.h>
 #include <linux/sched.h>
 #include <sys/syscall.h>
 #include <linux/kcmp.h>
@@ -1434,6 +1436,92 @@ static void walk_threads(struct lsfd_control *ctl, struct path_cxt *pc,
        }
 }
 
+static int pollfdcmp(const void *a, const void *b)
+{
+       const struct pollfd *apfd = a, *bpfd = b;
+
+       return apfd->fd - bpfd->fd;
+}
+
+static void mark_poll_fds_as_multiplexed(char *buf,
+                                        pid_t pid, struct proc *proc)
+{
+       long fds;
+       long nfds;
+
+       struct iovec  local;
+       struct iovec  remote;
+       ssize_t n;
+
+       struct list_head *f;
+
+       if (sscanf(buf, "%lx %lx", &fds, &nfds) != 2)
+               return;
+
+       if (nfds == 0)
+               return;
+
+       local.iov_len = sizeof(struct pollfd) * nfds;
+       local.iov_base = xmalloc(local.iov_len);
+       remote.iov_len = local.iov_len;
+       remote.iov_base = (void *)fds;
+
+       n = process_vm_readv(pid, &local, 1, &remote, 1, 0);
+       if (n < 0 || ((size_t)n) != local.iov_len)
+               goto out;
+
+       qsort(local.iov_base, nfds, sizeof(struct pollfd), pollfdcmp);
+
+       list_for_each (f, &proc->files) {
+               struct file *file = list_entry(f, struct file, files);
+               if (is_opened_file(file) && !file->multiplexed) {
+                       int fd = file->association;
+                       if (bsearch(&(struct pollfd){.fd = fd,}, local.iov_base,
+                                   nfds, sizeof(struct pollfd), pollfdcmp))
+                               file->multiplexed = 1;
+               }
+       }
+
+ out:
+       free (local.iov_base);
+}
+
+static void parse_proc_syscall(struct lsfd_control *ctl __attribute__((__unused__)),
+                              struct path_cxt *pc, pid_t pid, struct proc *proc)
+{
+       char buf[BUFSIZ];
+       char *ptr = NULL;
+       long scn;
+
+       if (procfs_process_get_syscall(pc, buf, sizeof(buf)) <= 0)
+               return;
+
+       errno  = 0;
+       scn = strtol(buf, &ptr, 10);
+       if (errno)
+               return;
+       if (scn < 0)
+               return;
+
+       switch (scn) {
+#ifdef         SYS_poll
+       case SYS_poll:
+               mark_poll_fds_as_multiplexed(ptr, pid, proc);
+               break;
+#endif
+#ifdef         SYS_ppoll
+       case SYS_ppoll:
+               mark_poll_fds_as_multiplexed(ptr, pid, proc);
+               break;
+#endif
+#ifdef         SYS_ppoll_time64
+       case SYS_ppoll_time64:
+               mark_poll_fds_as_multiplexed(ptr, pid, proc);
+               break;
+#endif
+       }
+}
+
 static void read_process(struct lsfd_control *ctl, struct path_cxt *pc,
                         pid_t pid, struct proc *leader)
 {
@@ -1503,11 +1591,16 @@ static void read_process(struct lsfd_control *ctl, struct path_cxt *pc,
        if (tsearch(proc, &proc_tree, proc_tree_compare) == NULL)
                errx(EXIT_FAILURE, _("failed to allocate memory"));
 
+       if (ctl->show_xmode)
+               parse_proc_syscall(ctl, pc, pid, proc);
+
        /* The tasks collecting overwrites @pc by /proc/<task-pid>/. Keep it as
         * the last path based operation in read_process()
         */
        if (ctl->threads && leader == NULL)
                walk_threads(ctl, pc, pid, proc, read_process);
+       else if (ctl->show_xmode)
+               walk_threads(ctl, pc, pid, proc, parse_proc_syscall);
 
        /* Let's be careful with number of open files */
         ul_path_close_dirfd(pc);