On 7/5/25 2:57 PM, Carl Johnson wrote:
Bash Version: 5.3 Patch Level: 0 Release Status: releaseDescription: When alias definition contains the 'unalias' builtin with the alias's name as its argument with a newline anywhere after the builtin invocation, running the alias when PROMPT_COMMAND is not empty causes a segmentation fault. Repeat-By: Start an bash shell, run the following code: ```bash PROMPT_COMMAND=: alias a=$'unalias a\n' a ``` The result is a segmentation fault.
Thanks for the report. In the general case, evaluating the value of a shell
variable as a command should save and restore the parser state. In this
edge case, though, it's not necessary because PROMPT_COMMAND is only
evaluated before parsing a command. The attached patch should fix it.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
*** ../bash-5.3/parse.y Thu Jun 12 12:36:06 2025
--- parse.y Sun Jul 6 16:46:00 2025
***************
*** 3009,3023 ****
void
! execute_variable_command (const char *command, const char *vname)
{
char *last_lastarg;
sh_parser_state_t ps;
! save_parser_state (&ps);
last_lastarg = save_lastarg ();
parse_and_execute (savestring (command), vname,
SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE|SEVAL_NOTIFY);
! restore_parser_state (&ps);
bind_lastarg (last_lastarg);
FREE (last_lastarg);
--- 3009,3025 ----
void
! execute_variable_command (const char *command, const char *vname, int flags)
{
char *last_lastarg;
sh_parser_state_t ps;
! if (flags)
! save_parser_state (&ps);
last_lastarg = save_lastarg ();
parse_and_execute (savestring (command), vname,
SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE|SEVAL_NOTIFY);
! if (flags)
! restore_parser_state (&ps);
bind_lastarg (last_lastarg);
FREE (last_lastarg);
*** ../bash-5.3/eval.c Fri Mar 7 18:50:03 2025
--- eval.c Sun Jul 6 16:49:18 2025
***************
*** 284,288 ****
/* Caller ensures that A has a non-zero number of elements */
int
! execute_array_command (ARRAY *a, void *v)
{
char *tag;
--- 284,288 ----
/* Caller ensures that A has a non-zero number of elements */
int
! execute_array_command (ARRAY *a, void *v, int flags)
{
char *tag;
***************
*** 296,300 ****
{
if (argv[i] && argv[i][0])
! execute_variable_command (argv[i], tag);
}
strvec_dispose (argv);
--- 296,300 ----
{
if (argv[i] && argv[i][0])
! execute_variable_command (argv[i], tag, flags);
}
strvec_dispose (argv);
***************
*** 319,323 ****
{
if ((pcmds = array_cell (pcv)) && array_num_elements (pcmds) > 0)
! execute_array_command (pcmds, "PROMPT_COMMAND");
return;
}
--- 319,323 ----
{
if ((pcmds = array_cell (pcv)) && array_num_elements (pcmds) > 0)
! execute_array_command (pcmds, "PROMPT_COMMAND", 0);
return;
}
***************
*** 328,332 ****
command_to_execute = value_cell (pcv);
if (command_to_execute && *command_to_execute)
! execute_variable_command (command_to_execute, "PROMPT_COMMAND");
}
--- 328,332 ----
command_to_execute = value_cell (pcv);
if (command_to_execute && *command_to_execute)
! execute_variable_command (command_to_execute, "PROMPT_COMMAND", 0);
}
*** ../bash-5.3/input.h Fri Mar 10 16:22:48 2023
--- input.h Sun Jul 6 16:45:42 2025
***************
*** 100,104 ****
extern int find_reserved_word (const char *);
extern void gather_here_documents (void);
! extern void execute_variable_command (const char *, const char *);
extern int *save_token_state (void);
--- 100,104 ----
extern int find_reserved_word (const char *);
extern void gather_here_documents (void);
! extern void execute_variable_command (const char *, const char *, int);
extern int *save_token_state (void);
*** ../bash-5.3/array.h Wed Dec 28 14:00:47 2022
--- array.h Sun Jul 6 16:47:27 2025
***************
*** 178,182 ****
/* In eval.c, but uses ARRAY * */
! extern int execute_array_command (ARRAY *, void *);
#endif /* _ARRAY_H_ */
--- 178,182 ----
/* In eval.c, but uses ARRAY * */
! extern int execute_array_command (ARRAY *, void *, int);
#endif /* _ARRAY_H_ */
*** ../bash-5.3/y.tab.c Mon Jun 30 09:56:25 2025
--- y.tab.c Sun Jul 6 17:38:06 2025
***************
*** 5368,5382 ****
void
! execute_variable_command (const char *command, const char *vname)
{
char *last_lastarg;
sh_parser_state_t ps;
! save_parser_state (&ps);
last_lastarg = save_lastarg ();
parse_and_execute (savestring (command), vname,
SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE|SEVAL_NOTIFY);
! restore_parser_state (&ps);
bind_lastarg (last_lastarg);
FREE (last_lastarg);
--- 5368,5384 ----
void
! execute_variable_command (const char *command, const char *vname, int flags)
{
char *last_lastarg;
sh_parser_state_t ps;
! if (flags)
! save_parser_state (&ps);
last_lastarg = save_lastarg ();
parse_and_execute (savestring (command), vname,
SEVAL_NONINT|SEVAL_NOHIST|SEVAL_NOOPTIMIZE|SEVAL_NOTIFY);
! if (flags)
! restore_parser_state (&ps);
bind_lastarg (last_lastarg);
FREE (last_lastarg);
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