Unverified Commit 727b5510 authored by Christian Brauner's avatar Christian Brauner
Browse files

coredump: massage format_corename() 

We're going to extend the coredump code in follow-up patches.
Clean it up so we can do this more easily.

Link: https://lore.kernel.org/20250516-work-coredump-socket-v8-1-664f3caf2516@kernel.org


Acked-by: default avatarSerge Hallyn <serge@hallyn.com>
Acked-by: default avatarLuca Boccassi <luca.boccassi@gmail.com>
Reviewed-by: default avatarJann Horn <jannh@google.com>
Reviewed-by: default avatarAlexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 4dd6566b

fs/coredump.c

+25 −21
Original line number Diff line number Diff line
@@ -76,9 +76,15 @@ static char core_pattern[CORENAME_MAX_SIZE] = "core"; 
static int core_name_size = CORENAME_MAX_SIZE;

unsigned int core_file_note_size_limit = CORE_FILE_NOTE_SIZE_DEFAULT;



enum coredump_type_t {

	COREDUMP_FILE = 1,

	COREDUMP_PIPE = 2,

};



struct core_name {

	char *corename;

	int used, size;

	enum coredump_type_t core_type;

};



static int expand_corename(struct core_name *cn, int size)
@@ -218,18 +224,21 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm, 
{

	const struct cred *cred = current_cred();

	const char *pat_ptr = core_pattern;

	int ispipe = (*pat_ptr == '|');

	bool was_space = false;

	int pid_in_pattern = 0;

	int err = 0;



	cn->used = 0;

	cn->corename = NULL;

	if (*pat_ptr == '|')

		cn->core_type = COREDUMP_PIPE;

	else

		cn->core_type = COREDUMP_FILE;

	if (expand_corename(cn, core_name_size))

		return -ENOMEM;

	cn->corename[0] = '\0';



	if (ispipe) {

	if (cn->core_type == COREDUMP_PIPE) {

		int argvs = sizeof(core_pattern) / 2;

		(*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL);

		if (!(*argv))
@@ -247,7 +256,7 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm, 
		 * Split on spaces before doing template expansion so that

		 * %e and %E don't get split if they have spaces in them

		 */

		if (ispipe) {

		if (cn->core_type == COREDUMP_PIPE) {

			if (isspace(*pat_ptr)) {

				if (cn->used != 0)

					was_space = true;
@@ -353,7 +362,7 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm, 
				 * Installing a pidfd only makes sense if

				 * we actually spawn a usermode helper.

				 */

				if (!ispipe)

				if (cn->core_type != COREDUMP_PIPE)

					break;



				/*
@@ -384,12 +393,9 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm, 
	 * If core_pattern does not include a %p (as is the default)

	 * and core_uses_pid is set, then .%pid will be appended to

	 * the filename. Do not do this for piped commands. */

	if (!ispipe && !pid_in_pattern && core_uses_pid) {

		err = cn_printf(cn, ".%d", task_tgid_vnr(current));

		if (err)

			return err;

	}

	return ispipe;

	if (cn->core_type == COREDUMP_FILE && !pid_in_pattern && core_uses_pid)

		return cn_printf(cn, ".%d", task_tgid_vnr(current));

	return 0;

}



static int zap_process(struct signal_struct *signal, int exit_code)
@@ -583,7 +589,6 @@ void do_coredump(const kernel_siginfo_t *siginfo) 
	const struct cred *old_cred;

	struct cred *cred;

	int retval = 0;

	int ispipe;

	size_t *argv = NULL;

	int argc = 0;

	/* require nonrelative corefile path and be extra careful */
@@ -632,19 +637,18 @@ void do_coredump(const kernel_siginfo_t *siginfo) 


	old_cred = override_creds(cred);



	ispipe = format_corename(&cn, &cprm, &argv, &argc);

	retval = format_corename(&cn, &cprm, &argv, &argc);

	if (retval < 0) {

		coredump_report_failure("format_corename failed, aborting core");

		goto fail_unlock;

	}



	if (ispipe) {

	if (cn.core_type == COREDUMP_PIPE) {

		int argi;

		int dump_count;

		char **helper_argv;

		struct subprocess_info *sub_info;



		if (ispipe < 0) {

			coredump_report_failure("format_corename failed, aborting core");

			goto fail_unlock;

		}



		if (cprm.limit == 1) {

			/* See umh_coredump_setup() which sets RLIMIT_CORE = 1.

			 *
@@ -695,7 +699,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) 
			coredump_report_failure("|%s pipe failed", cn.corename);

			goto close_fail;

		}

	} else {

	} else if (cn.core_type == COREDUMP_FILE) {

		struct mnt_idmap *idmap;

		struct inode *inode;

		int open_flags = O_CREAT | O_WRONLY | O_NOFOLLOW |
@@ -823,13 +827,13 @@ void do_coredump(const kernel_siginfo_t *siginfo) 
		file_end_write(cprm.file);

		free_vma_snapshot(&cprm);

	}

	if (ispipe && core_pipe_limit)

	if ((cn.core_type == COREDUMP_PIPE) && core_pipe_limit)

		wait_for_dump_helpers(cprm.file);

close_fail:

	if (cprm.file)

		filp_close(cprm.file, NULL);

fail_dropcount:

	if (ispipe)

	if (cn.core_type == COREDUMP_PIPE)

		atomic_dec(&core_dump_count);

fail_unlock:

	kfree(argv);