migration-exec.c

   1 /*
   2  * QEMU live migration
   3  *
   4  * Copyright IBM, Corp. 2008
   5  * Copyright Dell MessageOne 2008
   6  *
   7  * Authors:
   8  *  Anthony Liguori   <aliguori@us.ibm.com>
   9  *  Charles Duffy     <charles_duffy@messageone.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2.  See
  12  * the COPYING file in the top-level directory.
  13  *
  14  * Contributions after 2012-01-13 are licensed under the terms of the
  15  * GNU GPL, version 2 or (at your option) any later version.
  16  */
  17
  18 #include "qemu-common.h"
  19 #include "qemu_socket.h"
  20 #include "migration.h"
  21 #include "qemu-char.h"
  22 #include "buffered_file.h"
  23 #include "block.h"
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26
  27 //#define DEBUG_MIGRATION_EXEC
  28
  29 #ifdef DEBUG_MIGRATION_EXEC
  30 #define DPRINTF(fmt, ...) \
  31     do { printf("migration-exec: " fmt, ## __VA_ARGS__); } while (0)
  32 #else
  33 #define DPRINTF(fmt, ...) \
  34     do { } while (0)
  35 #endif
  36
  37 static int file_errno(MigrationState *s)
  38 {
  39     return errno;
  40 }
  41
  42 static int file_write(MigrationState *s, const void * buf, size_t size)
  43 {
  44     return write(s->fd, buf, size);
  45 }
  46
  47 static int exec_close(MigrationState *s)
  48 {
  49     int ret = 0;
  50     DPRINTF("exec_close\n");
  51     if (s->opaque) {
  52         ret = qemu_fclose(s->opaque);
  53         s->opaque = NULL;
  54         s->fd = -1;
  55         if (ret >= 0 && !(WIFEXITED(ret) && WEXITSTATUS(ret) == 0)) {
  56             /* close succeeded, but non-zero exit code: */
  57             ret = -EIO; /* fake errno value */
  58         }
  59     }
  60     return ret;
  61 }
  62
  63 int exec_start_outgoing_migration(MigrationState *s, const char *command)
  64 {
  65     FILE *f;
  66
  67     f = popen(command, "w");
  68     if (f == NULL) {
  69         DPRINTF("Unable to popen exec target\n");
  70         goto err_after_popen;
  71     }
  72
  73     s->fd = fileno(f);
  74     if (s->fd == -1) {
  75         DPRINTF("Unable to retrieve file descriptor for popen'd handle\n");
  76         goto err_after_open;
  77     }
  78
  79     socket_set_nonblock(s->fd);
  80
  81     s->opaque = qemu_popen(f, "w");
  82
  83     s->close = exec_close;
  84     s->get_error = file_errno;
  85     s->write = file_write;
  86
  87     migrate_fd_connect(s);
  88     return 0;
  89
  90 err_after_open:
  91     pclose(f);
  92 err_after_popen:
  93     return -1;
  94 }
  95
  96 static void exec_accept_incoming_migration(void *opaque)
  97 {
  98     QEMUFile *f = opaque;
  99
 100     process_incoming_migration(f);
 101     qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
 102     qemu_fclose(f);
 103 }
 104
 105 int exec_start_incoming_migration(const char *command)
 106 {
 107     QEMUFile *f;
 108
 109     DPRINTF("Attempting to start an incoming migration\n");
 110     f = qemu_popen_cmd(command, "r");
 111     if(f == NULL) {
 112         DPRINTF("Unable to apply qemu wrapper to popen file\n");
 113         return -errno;
 114     }
 115
 116     qemu_set_fd_handler2(qemu_stdio_fd(f), NULL,
 117                          exec_accept_incoming_migration, NULL, f);
 118
 119     return 0;
 120 }