arch/um/drivers/slirp_user.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4  */
   5
   6 #include <unistd.h>
   7 #include <errno.h>
   8 #include <string.h>
   9 #include <sys/wait.h>
  10 #include <net_user.h>
  11 #include <os.h>
  12 #include "slirp.h"
  13
  14 static int slirp_user_init(void *data, void *dev)
  15 {
  16         struct slirp_data *pri = data;
  17
  18         pri->dev = dev;
  19         return 0;
  20 }
  21
  22 struct slirp_pre_exec_data {
  23         int stdin_fd;
  24         int stdout_fd;
  25 };
  26
  27 static void slirp_pre_exec(void *arg)
  28 {
  29         struct slirp_pre_exec_data *data = arg;
  30
  31         if (data->stdin_fd != -1)
  32                 dup2(data->stdin_fd, 0);
  33         if (data->stdout_fd != -1)
  34                 dup2(data->stdout_fd, 1);
  35 }
  36
  37 static int slirp_tramp(char **argv, int fd)
  38 {
  39         struct slirp_pre_exec_data pe_data;
  40         int pid;
  41
  42         pe_data.stdin_fd = fd;
  43         pe_data.stdout_fd = fd;
  44         pid = run_helper(slirp_pre_exec, &pe_data, argv);
  45
  46         return pid;
  47 }
  48
  49 static int slirp_open(void *data)
  50 {
  51         struct slirp_data *pri = data;
  52         int fds[2], pid, err;
  53
  54         err = os_pipe(fds, 1, 1);
  55         if (err)
  56                 return err;
  57
  58         err = slirp_tramp(pri->argw.argv, fds[1]);
  59         if (err < 0) {
  60                 printk(UM_KERN_ERR "slirp_tramp failed - errno = %d\n", -err);
  61                 goto out;
  62         }
  63         pid = err;
  64
  65         pri->slave = fds[1];
  66         pri->slip.pos = 0;
  67         pri->slip.esc = 0;
  68         pri->pid = err;
  69
  70         return fds[0];
  71 out:
  72         close(fds[0]);
  73         close(fds[1]);
  74         return err;
  75 }
  76
  77 static void slirp_close(int fd, void *data)
  78 {
  79         struct slirp_data *pri = data;
  80         int err;
  81
  82         close(fd);
  83         close(pri->slave);
  84
  85         pri->slave = -1;
  86
  87         if (pri->pid<1) {
  88                 printk(UM_KERN_ERR "slirp_close: no child process to shut "
  89                        "down\n");
  90                 return;
  91         }
  92
  93 #if 0
  94         if (kill(pri->pid, SIGHUP)<0) {
  95                 printk(UM_KERN_ERR "slirp_close: sending hangup to %d failed "
  96                        "(%d)\n", pri->pid, errno);
  97         }
  98 #endif
  99         err = helper_wait(pri->pid);
 100         if (err < 0)
 101                 return;
 102
 103         pri->pid = -1;
 104 }
 105
 106 int slirp_user_read(int fd, void *buf, int len, struct slirp_data *pri)
 107 {
 108         return slip_proto_read(fd, buf, len, &pri->slip);
 109 }
 110
 111 int slirp_user_write(int fd, void *buf, int len, struct slirp_data *pri)
 112 {
 113         return slip_proto_write(fd, buf, len, &pri->slip);
 114 }
 115
 116 const struct net_user_info slirp_user_info = {
 117         .init           = slirp_user_init,
 118         .open           = slirp_open,
 119         .close          = slirp_close,
 120         .remove         = NULL,
 121         .add_address    = NULL,
 122         .delete_address = NULL,
 123         .mtu            = BUF_SIZE,
 124         .max_packet     = BUF_SIZE,
 125 };