At least under Wine they are not recognized and you just see literal "[0m" etc appearing in the output.

Updates: commit 5a011e02375912f2ad88de1ebc6d609e29d38f71 Reviewed-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- server/debug.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/server/debug.c b/server/debug.c index 1b5ddaafe..2231d40a0 100644 --- a/server/debug.c +++ b/server/debug.c @@ -70,7 +70,9 @@ static void debug_common (bool in_server, const char *fs, va_list args) { int err = errno; +#ifndef WIN32 int tty; +#endif

CLEANUP_FREE char *str = NULL; size_t len = 0; FILE *fp; @@ -88,15 +90,19 @@ debug_common (bool in_server, const char *fs, va_list args) return; } +#ifndef WIN32 tty = isatty (fileno (stderr)); if (!in_server && tty) ansi_force_colour (ANSI_FG_BOLD_BLACK, fp); +#endif

prologue (fp); errno = err; vfprintf (fp, fs, args); +#ifndef WIN32 if (!in_server && tty) ansi_force_restore (fp); +#endif

eg. { '\r', '\n' } -> { '\\', 'n', '\\', 'r' } --- common/utils/utils.h | 1 + common/utils/quote.c | 58 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff --git a/common/utils/utils.h b/common/utils/utils.h index 42288a5cd..1e6d8972b 100644 --- a/common/utils/utils.h +++ b/common/utils/utils.h @@ -35,6 +35,7 @@ extern void shell_quote (const char *str, FILE *fp); extern void uri_quote (const char *str, FILE *fp); +extern void c_string_quote (const char *str, FILE *fp); extern int exit_status_to_nbd_error (int status, const char *cmd); extern int set_cloexec (int fd); extern int set_nonblock (int fd); diff --git a/common/utils/quote.c b/common/utils/quote.c index 863e08a8e..877035387 100644 --- a/common/utils/quote.c +++ b/common/utils/quote.c @@ -37,6 +37,9 @@ #include <string.h> #include <unistd.h> +#include "ascii-ctype.h" +#include "hexdigit.h" + /* Print str to fp, shell quoting if necessary. This comes from * libguestfs, but was written by me so I'm relicensing it to a BSD * license for nbdkit. @@ -98,3 +101,58 @@ uri_quote (const char *str, FILE *fp) fprintf (fp, "%%%02X", str[i] & 0xff); } } + +/* Print str to fp, quoting in a way similar to C strings, for example + * '\n' -> "\n". + * + * Note that we do not emit quotes around the string, and double + * quotes within the string are not escaped. + */ +void +c_string_quote (const char *str, FILE *fp) +{ + size_t i; + char c; + + for (i = 0; c = str[i], c != '\0'; ++i) { + if (ascii_isprint (c)) + fputc (c, fp); + else { + switch (c) { + case '\a': + fputc ('\\', fp); + fputc ('a', fp); + break; + case '\b': + fputc ('\\', fp); + fputc ('b', fp); + break; + case '\f': + fputc ('\\', fp); + fputc ('f', fp); + break; + case '\n': + fputc ('\\', fp); + fputc ('n', fp); + break; + case '\r': + fputc ('\\', fp); + fputc ('r', fp); + break; + case '\t': + fputc ('\\', fp); + fputc ('t', fp); + break; + case '\v': + fputc ('\\', fp); + fputc ('v', fp); + break; + default: + fputc ('\\', fp); + fputc ('x', fp); + fputc (hexchar (c >> 4), fp); + fputc (hexchar (c), fp); + } + } + } +}

On Tue, May 09, 2023 at 03:51:21PM +0100, Richard W.M. Jones wrote: > Debug strings contain all kinds of information including some under > user control. Previously we simply sent everything to stderr, but > this is potentially insecure, as well as not dealing well with > non-printable characters. Escape these strings when printing. > --- > server/debug.c | 38 +++++++++++++++++++++++--------------- > 1 file changed, 23 insertions(+), 15 deletions(-) > > diff --git a/server/debug.c b/server/debug.c > index 177d9d5da..6cf1af316 100644 > --- a/server/debug.c > +++ b/server/debug.c > @@ -42,6 +42,7 @@ > > #include "ansi-colours.h" > #include "open_memstream.h" > +#include "utils.h" > > #include "internal.h" > > @@ -76,36 +77,43 @@ debug_common (bool in_server, const char *fs, va_list args) > #ifndef WIN32 > int tty; > #endif > - CLEANUP_FREE char *str = NULL; > - size_t len = 0; > - FILE *fp; > + CLEANUP_FREE char *str_inner = NULL; > + CLEANUP_FREE char *str_outer = NULL; > + FILE *fp_inner, *fp_outer; > + size_t len_inner = 0, len_outer = 0; > > - fp = open_memstream (&str, &len); > - if (fp == NULL) > + /* The "inner" string is the debug string before escaping. */ > + fp_inner = open_memstream (&str_inner, &len_inner); > + if (fp_inner == NULL) > goto fail; > + errno = err; > + vfprintf (fp_inner, fs, args); > + close_memstream (fp_inner); Missing the check for failure. > + > + /* The "outer" string contains the prologue, escaped debug string and \n. */ > + fp_outer = open_memstream (&str_outer, &len_outer); > + if (fp_outer == NULL) goto fail; > > #ifndef WIN32 > tty = isatty (fileno (stderr)); > - if (!in_server && tty) ansi_force_colour (ANSI_FG_BOLD_BLACK, fp); > + if (!in_server && tty) ansi_force_colour (ANSI_FG_BOLD_BLACK, fp_outer); > #endif > > - prologue (fp); > - > - errno = err; > - vfprintf (fp, fs, args); > + prologue (fp_outer); > + c_string_quote (str_inner, fp_outer); > > #ifndef WIN32 > - if (!in_server && tty) ansi_force_restore (fp); > + if (!in_server && tty) ansi_force_restore (fp_outer); > #endif > - fprintf (fp, "\n"); > - if (close_memstream (fp) == -1) > + fprintf (fp_outer, "\n"); > + if (close_memstream (fp_outer) == -1) Affects multiple patches: close_memstream() (on Linux) fails with EOF, which happens to be -1 on all sane libc, but which POSIX says can be any negative value. '< 0' or at least '== EOF' is probably safer than '== -1'.