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Diffstat (limited to 'tools/libxl/libxl_save_helper.c')
| -rw-r--r-- | tools/libxl/libxl_save_helper.c | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/tools/libxl/libxl_save_helper.c b/tools/libxl/libxl_save_helper.c new file mode 100644 index 0000000000..772251af0c --- /dev/null +++ b/tools/libxl/libxl_save_helper.c @@ -0,0 +1,283 @@ +/* + * Copyright (C) 2012 Citrix Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; version 2.1 only. with the special + * exception on linking described in file LICENSE. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + */ + +/* + * The libxl-save-helper utility speaks a protocol to its caller for + * the callbacks. The protocol is as follows. + * + * The helper talks on stdin and stdout, in binary in machine + * endianness. The helper speaks first, and only when it has a + * callback to make. It writes a 16-bit number being the message + * length, and then the message body. + * + * Each message starts with a 16-bit number indicating which of the + * messages it is, and then some arguments in a binary marshalled form. + * If the callback does not need a reply (it returns void), the helper + * just continues. Otherwise the helper waits for its caller to send a + * single int which is to be the return value from the callback. + * + * Where feasible the stubs and callbacks have prototypes identical to + * those required by xc_domain_save and xc_domain_restore, so that the + * autogenerated functions can be used/provided directly. + * + * The actual messages are in the array @msgs in libxl_save_msgs_gen.pl + */ + +#include "libxl_osdeps.h" + +#include <stdlib.h> +#include <unistd.h> +#include <assert.h> +#include <inttypes.h> + +#include "libxl.h" + +#include "xenctrl.h" +#include "xenguest.h" +#include "_libxl_save_msgs_helper.h" + +/*----- globals -----*/ + +static const char *program = "libxl-save-helper"; +static xentoollog_logger *logger; +static xc_interface *xch; + +/*----- error handling -----*/ + +static void fail(int errnoval, const char *fmt, ...) + __attribute__((noreturn,format(printf,2,3))); +static void fail(int errnoval, const char *fmt, ...) +{ + va_list al; + va_start(al,fmt); + xtl_logv(logger,XTL_ERROR,errnoval,program,fmt,al); + exit(-1); +} + +static int read_exactly(int fd, void *buf, size_t len) +/* returns 0 if we get eof, even if we got it midway through; 1 if ok */ +{ + while (len) { + ssize_t r = read(fd, buf, len); + if (r<=0) return r; + assert(r <= len); + len -= r; + buf = (char*)buf + r; + } + return 1; +} + +static void *xmalloc(size_t sz) +{ + if (!sz) return 0; + void *r = malloc(sz); + if (!r) { perror("memory allocation failed"); exit(-1); } + return r; +} + +/*----- logger -----*/ + +typedef struct { + xentoollog_logger vtable; +} xentoollog_logger_tellparent; + +static void tellparent_vmessage(xentoollog_logger *logger_in, + xentoollog_level level, + int errnoval, + const char *context, + const char *format, + va_list al) +{ + char *formatted; + int r = vasprintf(&formatted, format, al); + if (r < 0) { perror("memory allocation failed during logging"); exit(-1); } + helper_stub_log(level, errnoval, context, formatted, 0); + free(formatted); +} + +static void tellparent_progress(struct xentoollog_logger *logger_in, + const char *context, + const char *doing_what, int percent, + unsigned long done, unsigned long total) +{ + helper_stub_progress(context, doing_what, done, total, 0); +} + +static void tellparent_destroy(struct xentoollog_logger *logger_in) +{ + abort(); +} + +static xentoollog_logger_tellparent *createlogger_tellparent(void) +{ + xentoollog_logger_tellparent newlogger; + return XTL_NEW_LOGGER(tellparent, newlogger); +} + +/*----- helper functions called by autogenerated stubs -----*/ + +unsigned char * helper_allocbuf(int len, void *user) +{ + return xmalloc(len); +} + +static void transmit(const unsigned char *msg, int len, void *user) +{ + while (len) { + int r = write(1, msg, len); + if (r<0) { perror("write"); exit(-1); } + assert(r >= 0); + assert(r <= len); + len -= r; + msg += r; + } +} + +void helper_transmitmsg(unsigned char *msg_freed, int len_in, void *user) +{ + assert(len_in < 64*1024); + uint16_t len = len_in; + transmit((const void*)&len, sizeof(len), user); + transmit(msg_freed, len, user); + free(msg_freed); +} + +int helper_getreply(void *user) +{ + int v; + int r = read_exactly(0, &v, sizeof(v)); + if (r<=0) exit(-2); + return v; +} + +/*----- other callbacks -----*/ + +static int toolstack_save_fd; +static uint32_t toolstack_save_len; + +static int toolstack_save_cb(uint32_t domid, uint8_t **buf, + uint32_t *len, void *data) +{ + assert(toolstack_save_fd > 0); + + int r = lseek(toolstack_save_fd, 0, SEEK_SET); + if (r) fail(errno,"rewind toolstack data tmpfile"); + + *buf = xmalloc(toolstack_save_len); + r = read_exactly(toolstack_save_fd, *buf, toolstack_save_len); + if (r<0) fail(errno,"read toolstack data"); + if (r==0) fail(0,"read toolstack data eof"); + + *len = toolstack_save_len; + return 0; +} + +static void startup(const char *op) { + logger = (xentoollog_logger*)createlogger_tellparent(); + if (!logger) { + fprintf(stderr, "%s: cannot initialise logger\n", program); + exit(-1); + } + + xtl_log(logger,XTL_DEBUG,0,program,"starting %s",op); + + xch = xc_interface_open(logger,logger,0); + if (!xch) fail(errno,"xc_interface_open failed"); +} + +static void complete(int retval) { + int errnoval = retval ? errno : 0; /* suppress irrelevant errnos */ + xtl_log(logger,XTL_DEBUG,errnoval,program,"complete r=%d",retval); + helper_stub_complete(retval,errnoval,0); + exit(0); +} + +static struct save_callbacks helper_save_callbacks; +static struct restore_callbacks helper_restore_callbacks; + +int main(int argc, char **argv) +{ + int r; + +#define NEXTARG (++argv, assert(*argv), *argv) + + const char *mode = *++argv; + assert(mode); + + if (!strcmp(mode,"--save-domain")) { + + int io_fd = atoi(NEXTARG); + uint32_t dom = strtoul(NEXTARG,0,10); + uint32_t max_iters = strtoul(NEXTARG,0,10); + uint32_t max_factor = strtoul(NEXTARG,0,10); + uint32_t flags = strtoul(NEXTARG,0,10); + int hvm = atoi(NEXTARG); + unsigned long genidad = strtoul(NEXTARG,0,10); + toolstack_save_fd = atoi(NEXTARG); + toolstack_save_len = strtoul(NEXTARG,0,10); + unsigned cbflags = strtoul(NEXTARG,0,10); + assert(!*++argv); + + if (toolstack_save_fd >= 0) + helper_save_callbacks.toolstack_save = toolstack_save_cb; + + helper_setcallbacks_save(&helper_save_callbacks, cbflags); + + startup("save"); + r = xc_domain_save(xch, io_fd, dom, max_iters, max_factor, flags, + &helper_save_callbacks, hvm, genidad); + complete(r); + + } else if (!strcmp(mode,"--restore-domain")) { + + int io_fd = atoi(NEXTARG); + uint32_t dom = strtoul(NEXTARG,0,10); + unsigned store_evtchn = strtoul(NEXTARG,0,10); + domid_t store_domid = strtoul(NEXTARG,0,10); + unsigned console_evtchn = strtoul(NEXTARG,0,10); + domid_t console_domid = strtoul(NEXTARG,0,10); + unsigned int hvm = strtoul(NEXTARG,0,10); + unsigned int pae = strtoul(NEXTARG,0,10); + int superpages = strtoul(NEXTARG,0,10); + int no_incr_genidad = strtoul(NEXTARG,0,10); + unsigned cbflags = strtoul(NEXTARG,0,10); + assert(!*++argv); + + helper_setcallbacks_restore(&helper_restore_callbacks, cbflags); + + unsigned long store_mfn = 0; + unsigned long console_mfn = 0; + unsigned long genidad = 0; + + startup("restore"); + r = xc_domain_restore(xch, io_fd, dom, store_evtchn, &store_mfn, + store_domid, console_evtchn, &console_mfn, + console_domid, hvm, pae, superpages, + no_incr_genidad, &genidad, + &helper_restore_callbacks); + helper_stub_restore_results(store_mfn,console_mfn,genidad,0); + complete(r); + + } else { + assert(!"unexpected mode argument"); + } +} + +/* + * Local variables: + * mode: C + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ |