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If ncurses is not supported, provide code to call "tputs" via popen(), but do not enable it because it is not very safe, and instead just assume colour is always available.

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This commit is contained in:
Andrew Wood
2024-12-17 22:48:43 +00:00
parent 76327fdf01
commit 02bf302f96
1 changed files with 65 additions and 5 deletions
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src/pv/display.c
+65 -5
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@@ -28,6 +28,16 @@
#endif
#endif
/*
* If USE_POPEN_TPUTS is defined, then we call popen("tputs") if ncurses is
* unavailable, when we need to know whether colours are supported.
*
* Since popen() is risky to call (in case $PATH has been altered), it is
* safer to just assume colour is available if we can't check, so
* USE_POPEN_TPUTS is undefined here by default.
*/
#undef USE_POPEN_TPUTS
/*
* We need sys/ioctl.h for ioctl() regardless of whether TIOCGWINSZ is
@@ -894,21 +904,71 @@ static void pv__format_init(pvstate_t state, /*@null@ */ const char *format_supp
) {
state->control.can_display_colour = true;
debug("%s: %s", term_env, "terminal supports colour");
} else {
state->control.can_display_colour = false;
debug("%s: %s", term_env, "terminal does not support colour");
}
} else {
/* If TERM is unset, disable colour. */
state->control.can_display_colour = false;
debug("%s", "no TERM variable - disabling colour support");
}
}
#else /* ! ENABLE_NCURSES */
# ifdef USE_POPEN_TPUTS /* (! ENABLE_NCURSES) && (USE_POPEN_TPUTS) */
/*
* Without terminal info support, always assume colour is
* supported.
* Without terminal info support, try running "tput colors"
* to determine whether colour is available, unless --force
* was supplied, in which case colour support is assumed.
*/
if (true == state->control.force) {
state->control.can_display_colour = true;
debug("%s", "force mode - assuming terminal supports colour");
} else {
FILE *command_fptr;
/*@-unrecog@ *//* splint doesn't know popen(). */
command_fptr = popen("tput colors 2>/dev/null", "r"); /* flawfinder: ignore */
/*@+unrecog@ */
/*
* flawfinder - we acknowledge that popen() is risky
* to call, though we have the mitigation that we're
* calling it with a static string.
*/
if (NULL == command_fptr) {
state->control.can_display_colour = false;
debug("%s (%s)", "popen failed - disabling colour support", strerror(errno));
} else {
int colour_count;
if (1 == fscanf(command_fptr, "%d", &colour_count)) {
if (colour_count > 1) {
state->control.can_display_colour = true;
debug("%s (%d)", "terminal supports colour", colour_count);
} else {
state->control.can_display_colour = false;
debug("%s (%d)",
"fewer than 2 colours available - disabling colour support");
}
} else {
state->control.can_display_colour = false;
debug("%s", "tput did not produce a number - disabling colour support");
}
/*@-unrecog@ *//* splint doesn't know pclose(). */
(void) pclose(command_fptr);
/*@+unrecog@ */
}
}
# else /* (! ENABLE_NCURSES) && (! USE_POPEN_TPUTS) */
/*
* Without terminal info support, just assume colour is
* available.
*/
/* TODO: call "tput colors" with popen() instead. */
state->control.can_display_colour = true;
debug("%s", "no terminal info support - assuming terminal supports colour");
#endif /* ENABLE_NCURSES */
debug("%s", "terminal info support not compiled in - assuming colour support");
# endif /* (! ENABLE_NCURSES) && (! USE_POPEN_TPUTS) */
#endif /* ! ENABLE_NCURSES */
}
}