search for: memstream

...int64_t size; const char *protocol; int tls_negotiated; + char *output = NULL; + size_t output_len = 0; progname = argv[0]; @@ -207,6 +210,17 @@ main (int argc, char *argv[]) if (map) probe_content = false; + /* Try to write output atomically. We spool output into a + * memstream, pointed to by fp, and write it all at once at the end. + * On error nothing should be printed on stdout. + */ + fp = open_memstream (&output, &output_len); + if (fp == NULL) { + fprintf (stderr, "%s: ", progname); + perror ("open_memstream"); + exit (EXIT...

...plete output > or the error message. > --- > info/Makefile.am | 1 + > info/info-atomic-output.sh | 32 ++++++ > info/nbdinfo.c | 194 ++++++++++++++++++++++--------------- > 3 files changed, 147 insertions(+), 80 deletions(-) ACK. Mostly mechanical, and memstreams make this nice. > +++ b/info/info-atomic-output.sh > @@ -0,0 +1,32 @@ > +. ../tests/functions.sh > + > +set -e > +set -x > + > +requires nbdkit --version > +requires nbdkit eval --version You could simplify this: if the second line passes, the first line is implied,...

...e); return -1; } @@ -103,7 +105,7 @@ make_iso (void) shell_quote (dirs[i], fp); } /* Redirect output to the temporary file. */ - fprintf (fp, " >&%d", fd); + fprintf (fp, " >&%d", iso_fd); if (fclose (fp) == EOF) { nbdkit_error ("memstream failed: %m"); @@ -128,8 +130,8 @@ iso_unload (void) free (dirs[i]); free (dirs); - if (fd >= 0) - close (fd); + if (iso_fd >= 0) + close (iso_fd); } static int @@ -193,25 +195,43 @@ iso_get_ready (void) static void * iso_open (int readonly) { - return NBDKIT_HAN...

...exportname=on option) > + > +static int > +tar_get_ready (void) > +{ > + FILE *fp; > + CLEANUP_FREE char *cmd = NULL; > + size_t len = 0; > + bool scanned_ok; > + char s[256]; > + > + /* Construct the tar command to examine the tar file. */ > + fp = open_memstream (&cmd, &len); > + if (fp == NULL) { > + nbdkit_error ("open_memstream: %m"); > + return -1; > + } > + fprintf (fp, "LANG=C tar --no-auto-compress -tRvf "); Use of --no-auto-compress is specific to GNU tar, do we care? Should we allow a 'tar=...

...tic int > >+tar_get_ready (void) > >+{ > >+ FILE *fp; > >+ CLEANUP_FREE char *cmd = NULL; > >+ size_t len = 0; > >+ bool scanned_ok; > >+ char s[256]; > >+ > >+ /* Construct the tar command to examine the tar file. */ > >+ fp = open_memstream (&cmd, &len); > >+ if (fp == NULL) { > >+ nbdkit_error ("open_memstream: %m"); > >+ return -1; > >+ } > >+ fprintf (fp, "LANG=C tar --no-auto-compress -tRvf "); > > Use of --no-auto-compress is specific to GNU tar, do we care...

This is an RFC only, at the very least it lacks tests. This implements a rather complex new feature in nbdkit-curl-plugin allowing you to specify an external shell script that can be used to fetch an authorization token for services which requires a token or cookie for access, especially if that token must be renewed periodically. The motivation can be seen in the changes to the docs in patch 2.

...t; + return size; > +} > + > +/* This creates and runs the full "mkfs" (or whatever) command. */ > +static int > +run_command (const char *disk) > +{ > + FILE *fp; > + CLEANUP_FREE char *cmd = NULL; > + size_t len = 0; > + int r; > + > + fp = open_memstream (&cmd, &len); > + if (fp == NULL) { > + nbdkit_error ("open_memstream: %m"); > + return -1; > + } > + > + /* Set the shell variables. */ > + fprintf (fp, "disk="); > + shell_quote (disk, fp); [1]...here you are correctly quoting the de...

.../* Create a temporary file for the errors so we can redirect them + * into nbdkit_error. + */ + fd = mkstemp (tmpfile); + if (fd == -1) { + nbdkit_error ("mkstemp"); + return -1; + } + close (fd); + + /* Generate the full script with the local $url variable. */ + fp = open_memstream (&cmd, &len); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + fprintf (fp, "exec </dev/null\n"); /* Avoid stdin leaking (nbdkit -s). */ + fprintf (fp, "exec 2>%s\n", tmpfile); /* Catch errors to a temporary file....

...TIVE; +} + +static int64_t +tmpdisk_get_size (void *handle) +{ + return size; +} + +/* This creates and runs the full "mkfs" (or whatever) command. */ +static int +run_command (const char *disk) +{ + FILE *fp; + CLEANUP_FREE char *cmd = NULL; + size_t len = 0; + int r; + + fp = open_memstream (&cmd, &len); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + + /* Set the shell variables. */ + fprintf (fp, "disk="); + shell_quote (disk, fp); + putc ('\n', fp); + if (label) { + fprintf (fp, "label="); +...

For context see these threads: https://lists.gnu.org/archive/html/qemu-discuss/2020-06/threads.html#00053 https://lists.gnu.org/archive/html/qemu-block/2020-06/threads.html#01496 Rich.

...dhat.com> wrote: ... > + > +static int > +tar_get_ready (void) > +{ > + FILE *fp; > + CLEANUP_FREE char *cmd = NULL; > + size_t len = 0; > + bool scanned_ok; > + char s[256]; > + > + /* Construct the tar command to examine the tar file. */ > + fp = open_memstream (&cmd, &len); > + if (fp == NULL) { > + nbdkit_error ("open_memstream: %m"); > + return -1; > + } > + fprintf (fp, "LANG=C tar --no-auto-compress -tRvf "); Using -R is nice, but is block size documented? Also --block-number would be nicer. >...

Evolution of this patch series: https://www.redhat.com/archives/libguestfs/2020-July/thread.html#00073 Instead of auth-script, this implements header-script and cookie-script. It can be used for similar purposes but the implementation is somewhat saner. Rich.

Unfinished (needs tests). This is my attempt to make a "remote tmpfs" plugin as outlined in this prior email: https://www.redhat.com/archives/libguestfs/2020-March/msg00134.html Although it would be possible to construct something a bit like this using existing plugins and filters (perhaps with some new features in those filters) I think it may be nicer to have a dedicated plugin for

...ir1 + * 34567 dir2 + * 46912 total + * + * We ignore everything except the first number on the last line. + */ +static int64_t +estimate_size (void) +{ + char *command = NULL, *line = NULL; + size_t len = 0; + FILE *fp; + int64_t ret; + int r; + + /* Create the du command. */ + fp = open_memstream (&command, &len); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + fprintf (fp, "du -c -k -s "); + shell_quote (dir, fp); + if (fclose (fp) == EOF) { + nbdkit_error ("memstream failed: %m"); + return -1; + } + + /...

.../* Create a temporary file for the errors so we can redirect them + * into nbdkit_error. + */ + fd = mkstemp (tmpfile); + if (fd == -1) { + nbdkit_error ("mkstemp"); + return -1; + } + close (fd); + + /* Generate the full script with the local $url variable. */ + fp = open_memstream (&cmd, &len); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + fprintf (fp, "exec </dev/null\n"); /* Avoid stdin leaking (nbdkit -s). */ + fprintf (fp, "exec 2>%s\n", tmpfile); /* Catch errors to a temporary file....

...;file=<FILENAME> The path inside the tar file to server." + +static int +tar_get_ready (void) +{ + FILE *fp; + CLEANUP_FREE char *cmd = NULL; + size_t len = 0; + bool scanned_ok; + char s[256]; + + /* Construct the tar command to examine the tar file. */ + fp = open_memstream (&cmd, &len); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + fprintf (fp, "LANG=C tar --no-auto-compress -tRvf "); + shell_quote (tarfile, fp); + fputc (' ', fp); + shell_quote (file, fp); + if (fclose (fp) == EOF) { +...

...false; + + assert (entry); + + /* Temporary file to capture the output from the tar command. */ + fd = mkstemp (output); + if (fd == -1) { + nbdkit_error ("mkstemp: %m"); + return -1; + } + close (fd); + + /* Construct the tar command to examine the tar file. */ + fp = open_memstream (&cmd, &cmdlen); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + fprintf (fp, "LANG=C tar --no-auto-compress -tRvf - "); + shell_quote (entry, fp); + fprintf (fp, " > "); + shell_quote (output, fp); + if (fclose (fp...

v2 was here: https://www.redhat.com/archives/libguestfs/2020-March/msg00154.html v3: - Micro-optimize tmpdir. - Quote $disk in default command shell fragment. - Don't redirect mkfs output to /dev/null. Instead use exec </dev/null >/dev/null before the shell fragment. We may want to do this in other places where we run external shell scripts, or more generally for all

For review only, this needs some clean up and more tests. My eyes are going cross-eyed looking at the calculate_offset_of_entry function, so time to take a break ... Rich.

...+ * 34567 dir2 + * 46912 total + * + * We ignore everything except the first number on the last line. + */ +static int64_t +estimate_size (void) +{ + char *command = NULL, *line = NULL; + size_t len = 0; + FILE *fp; + size_t i; + int64_t ret; + + /* Create the du command. */ + fp = open_memstream (&command, &len); + if (fp == NULL) { + nbdkit_error ("open_memstream: %m"); + return -1; + } + fprintf (fp, "du -c -k -s"); + for (i = 0; i < nr_dirs; ++i) { + fputc (' ', fp); + shell_quote (dirs[i], fp); + } + if (fclose (fp) == EOF) { +...