Re: [Xen-devel] [PATCH 2 of 2] xl: Make clear distinction between "filename" and "data source"

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

On 15/05/12 16:29, Ian Campbell wrote:
> On Tue, 2012-05-15 at 15:51 +0100, George Dunlap wrote:
> > Many places in xl there's a variable or element named "filename" which
> > does not contain a filename, but the source of the data for reporting
> > purposes.  Worse, there are variables which are sometimes actually
> > used or interpreted as a filename depending on what other variables
> > are set.  This makes it difficult to tell when a string is purely
> > cosmetic, and when another bit of code may actually attempt to call
> > "open" with the string.
> >
> > This patch makes a consistent distinction between "filename" (which
> > always refers to the name of an actual file, and may be interpreted as
> > such at some point) and "source" (which may be a filename, or may be
> > another data source such as a migration stream or saved data).
> >
> > This does add some variables and reshuffle where assignments happen;
> > most notably, the "restore_filename" element of struct domain_create
> > is now only set when restoring from a file.
> >
> > But at a high level, there should be no funcitonal changes.
> >
> > Signed-off-by: George Dunlap<george.dunlap@xxxxxxxxxxxxx>
> I've committed this (and the preceding patch), there were a few
> conflicts with Goncalo's vncviewer patch (a new param to
> parse_config_data). Please do check I've done the right thing.
Looks like you missed one s/config_file/config_source/ for 
parse_config_data; I'll follow-up with a patch.
 -George
> > diff -r 750b4dbab4b5 -r d555dd6614af tools/libxl/libxl_utils.c
> > --- a/tools/libxl/libxl_utils.c Tue May 15 15:45:55 2012 +0100
> > +++ b/tools/libxl/libxl_utils.c Tue May 15 15:51:25 2012 +0100
> > @@ -334,7 +334,7 @@ int libxl_read_file_contents(libxl_ctx *
> >                                                                             \
> >     int libxl_##rw##_exactly(libxl_ctx *ctx, int fd,                 \
> >                              constdata void *data, ssize_t sz,              \
> > -                           const char *filename, const char *what) {      \
> > +                           const char *source, const char *what) {      \
> >         ssize_t got;                                                        \
> >                                                                             \
> >         while (sz>  0) {                                                    \
> > @@ -343,7 +343,7 @@ int libxl_read_file_contents(libxl_ctx *
> >                 if (errno == EINTR) continue;                               \
> >                 if (!ctx) return errno;                                     \
> >                 LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "failed to " #rw " 
> > %s%s%s", \
> > -                           what?what:"", what?" from ":"", filename);     \
> > +                           what?what:"", what?" from ":"", source);       \
> >                 return errno;                                               \
> >             }                                                               \
> >             if (got == 0) {                                                 \
> > @@ -352,7 +352,7 @@ int libxl_read_file_contents(libxl_ctx *
> >                        zero_is_eof                                          \
> >                        ? "file/stream truncated reading %s%s%s"             \
> >                        : "file/stream write returned 0! writing %s%s%s",    \
> > -                     what?what:"", what?" from ":"", filename);           \
> > +                     what?what:"", what?" from ":"", source);             \
> >                 return EPROTO;                                              \
> >             }                                                               \
> >             sz -= got;                                                      \
> > diff -r 750b4dbab4b5 -r d555dd6614af tools/libxl/xl_cmdimpl.c
> > --- a/tools/libxl/xl_cmdimpl.c  Tue May 15 15:45:55 2012 +0100
> > +++ b/tools/libxl/xl_cmdimpl.c  Tue May 15 15:51:25 2012 +0100
> > @@ -520,9 +520,9 @@ vcpp_out:
> >       return rc;
> >   }
> >
> > -static void parse_config_data(const char *configfile_filename_report,
> > -                              const char *configfile_data,
> > -                              int configfile_len,
> > +static void parse_config_data(const char *config_source,
> > +                              const char *config_data,
> > +                              int config_len,
> >                                 libxl_domain_config *d_config)
> >   {
> >       const char *buf;
> > @@ -537,15 +537,15 @@ static void parse_config_data(const char
> >       libxl_domain_create_info *c_info =&d_config->c_info;
> >       libxl_domain_build_info *b_info =&d_config->b_info;
> >
> > -    config= xlu_cfg_init(stderr, configfile_filename_report);
> > +    config= xlu_cfg_init(stderr, config_source);
> >       if (!config) {
> >           fprintf(stderr, "Failed to allocate for configuration\n");
> >           exit(1);
> >       }
> >
> > -    e= xlu_cfg_readdata(config, configfile_data, configfile_len);
> > +    e= xlu_cfg_readdata(config, config_data, config_len);
> >       if (e) {
> > -        fprintf(stderr, "Failed to parse config file: %s\n", strerror(e));
> > +        fprintf(stderr, "Failed to parse config: %s\n", strerror(e));
> >           exit(1);
> >       }
> >
> > @@ -1524,6 +1524,8 @@ static int create_domain(struct domain_c
> >       const char *config_file = dom_info->config_file;
> >       const char *extra_config = dom_info->extra_config;
> >       const char *restore_file = dom_info->restore_file;
> > +    const char *config_source = NULL;
> > +    const char *restore_source = NULL;
> >       int migrate_fd = dom_info->migrate_fd;
> >
> >       int i;
> > @@ -1539,24 +1541,28 @@ static int create_domain(struct domain_c
> >       pid_t child_console_pid = -1;
> >       struct save_file_header hdr;
> >
> > +    int restoring = (restore_file || (migrate_fd>= 0));
> > +
> >       libxl_domain_config_init(&d_config);
> >
> > -    if (restore_file) {
> > +    if (restoring) {
> >           uint8_t *optdata_begin = 0;
> >           const uint8_t *optdata_here = 0;
> >           union { uint32_t u32; char b[4]; } u32buf;
> >           uint32_t badflags;
> >
> >           if (migrate_fd>= 0) {
> > +            restore_source = "<incoming migration stream>";
> >               restore_fd = migrate_fd;
> >           } else {
> > +            restore_source = restore_file;
> >               restore_fd = open(restore_file, O_RDONLY);
> >               rc = libxl_fd_set_cloexec(ctx, restore_fd, 1);
> >               if (rc) return rc;
> >           }
> >
> >           CHK_ERRNO( libxl_read_exactly(ctx, restore_fd,&hdr,
> > -                   sizeof(hdr), restore_file, "header") );
> > +                   sizeof(hdr), restore_source, "header") );
> >           if (memcmp(hdr.magic, savefileheader_magic, sizeof(hdr.magic))) {
> >               fprintf(stderr, "File has wrong magic number -"
> >                       " corrupt or for a different tool?\n");
> > @@ -1569,7 +1575,7 @@ static int create_domain(struct domain_c
> >           fprintf(stderr, "Loading new save file %s"
> >                   " (new xl fmt info"
> >                   " 0x%"PRIx32"/0x%"PRIx32"/%"PRIu32")\n",
> > -                restore_file, hdr.mandatory_flags, hdr.optional_flags,
> > +                restore_source, hdr.mandatory_flags, hdr.optional_flags,
> >                   hdr.optional_data_len);
> >
> >           badflags = hdr.mandatory_flags&  ~( 0 /* none understood yet */ );
> > @@ -1582,7 +1588,7 @@ static int create_domain(struct domain_c
> >           if (hdr.optional_data_len) {
> >               optdata_begin = xmalloc(hdr.optional_data_len);
> >               CHK_ERRNO( libxl_read_exactly(ctx, restore_fd, optdata_begin,
> > -                   hdr.optional_data_len, restore_file, "optdata") );
> > +                   hdr.optional_data_len, restore_source, "optdata") );
> >           }
> >
> >   #define OPTDATA_LEFT  (hdr.optional_data_len - (optdata_here - optdata_begin))
> > @@ -1617,7 +1623,7 @@ static int create_domain(struct domain_c
> >                                          &config_data,&config_len);
> >           if (ret) { fprintf(stderr, "Failed to read config file: %s: %s\n",
> >                              config_file, strerror(errno)); return ERROR_FAIL; }
> > -        if (!restore_file&&  extra_config&&  strlen(extra_config)) {
> > +        if (!restoring&&  extra_config&&  strlen(extra_config)) {
> >               if (config_len>  INT_MAX - (strlen(extra_config) + 2 + 1)) {
> >                   fprintf(stderr, "Failed to attach extra configration\n");
> >                   return ERROR_FAIL;
> > @@ -1632,19 +1638,20 @@ static int create_domain(struct domain_c
> >               config_len += sprintf(config_data + config_len, "\n%s\n",
> >                   extra_config);
> >           }
> > +        config_source=config_file;
> >       } else {
> >           if (!config_data) {
> >               fprintf(stderr, "Config file not specified and"
> >                       " none in save file\n");
> >               return ERROR_INVAL;
> >           }
> > -        config_file = "<saved>";
> > +        config_source = "<saved>";
> >       }
> >
> >       if (!dom_info->quiet)
> > -        printf("Parsing config file %s\n", config_file);
> > -
> > -    parse_config_data(config_file, config_data, config_len,&d_config);
> > +        printf("Parsing config from %s\n", config_source);
> > +
> > +    parse_config_data(config_source, config_data, config_len,&d_config);
> >
> >       if (migrate_fd>= 0) {
> >           if (d_config.c_info.name) {
> > @@ -1698,7 +1705,7 @@ start:
> >           autoconnect_console_how = 0;
> >       }
> >
> > -    if ( restore_file ) {
> > +    if ( restoring ) {
> >           ret = libxl_domain_create_restore(ctx,&d_config,
> >                                             &domid, restore_fd,
> >                                             0, autoconnect_console_how);
> > @@ -2559,7 +2566,7 @@ static void list_domains_details(const l
> >   {
> >       libxl_domain_config d_config;
> >
> > -    char *config_file;
> > +    char *config_source;
> >       uint8_t *data;
> >       int i, len, rc;
> >
> > @@ -2570,13 +2577,13 @@ static void list_domains_details(const l
> >           rc = libxl_userdata_retrieve(ctx, info[i].domid, "xl",&data,&len);
> >           if (rc)
> >               continue;
> > -        CHK_ERRNO(asprintf(&config_file, "<domid %d data>", info[i].domid));
> > +        CHK_ERRNO(asprintf(&config_source, "<domid %d data>", info[i].domid));
> >           libxl_domain_config_init(&d_config);
> > -        parse_config_data(config_file, (char *)data, len,&d_config);
> > +        parse_config_data(config_source, (char *)data, len,&d_config);
> >           printf_info(default_output_format, info[i].domid,&d_config);
> >           libxl_domain_config_dispose(&d_config);
> >           free(data);
> > -        free(config_file);
> > +        free(config_source);
> >       }
> >   }
> >
> > @@ -2679,7 +2686,7 @@ static void save_domain_core_begin(const
> >       }
> >   }
> >
> > -static void save_domain_core_writeconfig(int fd, const char *filename,
> > +static void save_domain_core_writeconfig(int fd, const char *source,
> >                                     const uint8_t *config_data, int config_len)
> >   {
> >       struct save_file_header hdr;
> > @@ -2708,13 +2715,13 @@ static void save_domain_core_writeconfig
> >       /* that's the optional data */
> >
> >       CHK_ERRNO( libxl_write_exactly(ctx, fd,
> > -&hdr, sizeof(hdr), filename, "header") );
> > +&hdr, sizeof(hdr), source, "header") );
> >       CHK_ERRNO( libxl_write_exactly(ctx, fd,
> > -        optdata_begin, hdr.optional_data_len, filename, "header") );
> > +        optdata_begin, hdr.optional_data_len, source, "header") );
> >
> >       fprintf(stderr, "Saving to %s new xl format (info"
> >               " 0x%"PRIx32"/0x%"PRIx32"/%"PRIu32")\n",
> > -            filename, hdr.mandatory_flags, hdr.optional_flags,
> > +            source, hdr.mandatory_flags, hdr.optional_flags,
> >               hdr.optional_data_len);
> >   }
> >
> > @@ -3039,7 +3046,6 @@ static void migrate_receive(int debug, i
> >       dom_info.daemonize = daemonize;
> >       dom_info.monitor = monitor;
> >       dom_info.paused = 1;
> > -    dom_info.restore_file = "incoming migration stream";
> >       dom_info.migrate_fd = 0; /* stdin */
> >       dom_info.migration_domname_r =&migration_domname;
> >       dom_info.incr_generationid = 0;
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel

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