[PATCH v4 01/11] coredump: massage format_corname()

Christian Brauner
2025-05-07T16:13:50Z

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

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
fs/coredump.c | 41 ++++++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/fs/coredump.c b/fs/coredump.c
index d740a0411266..281320ea351f 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -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 +393,12 @@ 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) {
+ if (!(cn->core_type == COREDUMP_PIPE) && !pid_in_pattern && core_uses_pid) {
err = cn_printf(cn, ".%d", task_tgid_vnr(current));
if (err)
return err;
}
- return ispipe;
+ return 0;
}

static int zap_process(struct signal_struct *signal, int exit_code)
@@ -583,7 +592,6 @@ 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 +640,18 @@ 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 +702,7 @@ 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 +830,13 @@ 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);

--
2.47.2