misc-utils/lsfd-fifo.c

   1 /*
   2  * lsfd-fifo.c - handle associations opening fifo objects
   3  *
   4  * Copyright (C) 2021 Red Hat, Inc. All rights reserved.
   5  * Written by Masatake YAMATO <yamato@redhat.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it would be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software Foundation,
  19  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "lsfd.h"
  23
  24 struct fifo {
  25         struct file file;
  26         struct ipc_endpoint endpoint;
  27 };
  28
  29 struct fifo_ipc {
  30         struct ipc ipc;
  31         ino_t ino;
  32 };
  33
  34 static inline char *fifo_xstrendpoint(struct file *file)
  35 {
  36         char *str = NULL;
  37         xasprintf(&str, "%d,%s,%d%c%c",
  38                   file->proc->pid, file->proc->command, file->association,
  39                   (file->mode & S_IRUSR)? 'r': '-',
  40                   (file->mode & S_IWUSR)? 'w': '-');
  41         return str;
  42 }
  43
  44 static bool fifo_fill_column(struct proc *proc __attribute__((__unused__)),
  45                              struct file *file,
  46                              struct libscols_line *ln,
  47                              int column_id,
  48                              size_t column_index)
  49 {
  50         char *str = NULL;
  51
  52         switch(column_id) {
  53         case COL_TYPE:
  54                 if (scols_line_set_data(ln, column_index, "FIFO"))
  55                         err(EXIT_FAILURE, _("failed to add output data"));
  56                 return true;
  57         case COL_SOURCE:
  58                 if (major(file->stat.st_dev) == 0
  59                     && strncmp(file->name, "pipe:", 5) == 0) {
  60                         str = xstrdup("pipefs");
  61                         break;
  62                 }
  63                 return false;
  64         case COL_ENDPOINTS: {
  65                 struct fifo *this = (struct fifo *)file;
  66                 struct list_head *e;
  67                 foreach_endpoint(e, this->endpoint) {
  68                         char *estr;
  69                         struct fifo *other = list_entry(e, struct fifo, endpoint.endpoints);
  70                         if (this == other)
  71                                 continue;
  72                         if (str)
  73                                 xstrputc(&str, '\n');
  74                         estr = fifo_xstrendpoint(&other->file);
  75                         xstrappend(&str, estr);
  76                         free(estr);
  77                 }
  78                 if (!str)
  79                         return false;
  80                 break;
  81         }
  82         default:
  83                 return false;
  84         }
  85
  86         if (!str)
  87                 err(EXIT_FAILURE, _("failed to add output data"));
  88         if (scols_line_refer_data(ln, column_index, str))
  89                 err(EXIT_FAILURE, _("failed to add output data"));
  90         return true;
  91 }
  92
  93 static unsigned int fifo_get_hash(struct file *file)
  94 {
  95         return (unsigned int)(file->stat.st_ino % UINT_MAX);
  96 }
  97
  98 static bool fifo_is_suitable_ipc(struct ipc *ipc, struct file *file)
  99 {
 100         return ((struct fifo_ipc *)ipc)->ino == file->stat.st_ino;
 101 }
 102
 103 static const struct ipc_class *fifo_get_ipc_class(struct file *file __attribute__((__unused__)))
 104 {
 105         static const struct ipc_class fifo_ipc_class = {
 106                 .size = sizeof(struct fifo_ipc),
 107                 .get_hash = fifo_get_hash,
 108                 .is_suitable_ipc = fifo_is_suitable_ipc,
 109                 .free = NULL,
 110         };
 111         return &fifo_ipc_class;
 112 }
 113
 114 static void fifo_initialize_content(struct file *file)
 115 {
 116         struct fifo *fifo = (struct fifo *)file;
 117         struct ipc *ipc;
 118         unsigned int hash;
 119
 120         init_endpoint(&fifo->endpoint);
 121         ipc = get_ipc(file);
 122         if (ipc)
 123                 goto link;
 124
 125         ipc = new_ipc(fifo_get_ipc_class(file));
 126         ((struct fifo_ipc *)ipc)->ino = file->stat.st_ino;
 127
 128         hash = fifo_get_hash(file);
 129         add_ipc(ipc, hash);
 130  link:
 131         add_endpoint(&fifo->endpoint, ipc);
 132 }
 133
 134 const struct file_class fifo_class = {
 135         .super = &file_class,
 136         .size = sizeof(struct fifo),
 137         .fill_column = fifo_fill_column,
 138         .initialize_content = fifo_initialize_content,
 139         .free_content = NULL,
 140         .get_ipc_class = fifo_get_ipc_class,
 141 };