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coredump: slighlty simplify stack trace generation logic

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The main advantage is to avoid the code duplication used to build MESSAGE=
field.

No functional changes.
This commit is contained in:
Franck Bui 2019-06-25 14:04:46 +02:00
parent 2705fcd63b
commit 51d3783d87
3 changed files with 33 additions and 31 deletions
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50
src/coredump/coredump.c
View File

@ -711,6 +711,7 @@ static int submit_coredump(
_cleanup_close_ int coredump_fd = -1, coredump_node_fd = -1;
_cleanup_free_ char *core_message = NULL, *filename = NULL, *coredump_data = NULL;
_cleanup_free_ char *stacktrace = NULL;
uint64_t coredump_size = UINT64_MAX;
bool truncated = false, journald_crash;
int r;
@ -732,8 +733,9 @@ static int submit_coredump(
/* Skip whole core dumping part */
goto log;
/* If we don't want to keep the coredump on disk, remove it now, as later on we will lack the privileges for
* it. However, we keep the fd to it, so that we can still process it and log it. */
/* If we don't want to keep the coredump on disk, remove it now, as later on we
* will lack the privileges for it. However, we keep the fd to it, so that we can
* still process it and log it. */
r = maybe_remove_external_coredump(filename, coredump_size);
if (r < 0)
return r;
@ -749,9 +751,10 @@ static int submit_coredump(
/* Vacuum again, but exclude the coredump we just created */
(void) coredump_vacuum(coredump_node_fd >= 0 ? coredump_node_fd : coredump_fd, arg_keep_free, arg_max_use);
/* Now, let's drop privileges to become the user who owns the segfaulted process and allocate the coredump
* memory under the user's uid. This also ensures that the credentials journald will see are the ones of the
* coredumping user, thus making sure the user gets access to the core dump. Let's also get rid of all
/* Now, let's drop privileges to become the user who owns the segfaulted process
* and allocate the coredump memory under the user's uid. This also ensures that
* the credentials journald will see are the ones of the coredumping user, thus
* making sure the user gets access to the core dump. Let's also get rid of all
* capabilities, if we run as root, we won't need them anymore. */
r = change_uid_gid(context);
if (r < 0)
@ -759,33 +762,22 @@ static int submit_coredump(
#if HAVE_ELFUTILS
/* Try to get a stack trace if we can */
if (coredump_size <= arg_process_size_max) {
_cleanup_free_ char *stacktrace = NULL;
r = coredump_make_stack_trace(coredump_fd, context[CONTEXT_EXE], &stacktrace);
if (r >= 0)
core_message = strjoin("MESSAGE=Process ", context[CONTEXT_PID],
" (", context[CONTEXT_COMM], ") of user ",
context[CONTEXT_UID], " dumped core.",
journald_crash ? "\nCoredump diverted to " : "",
journald_crash ? filename : "",
"\n\n", stacktrace);
else if (r == -EINVAL)
log_warning("Failed to generate stack trace: %s", dwfl_errmsg(dwfl_errno()));
else
log_warning_errno(r, "Failed to generate stack trace: %m");
} else
log_debug("Not generating stack trace: core size %"PRIu64" is greater than %"PRIu64" (the configured maximum)",
if (coredump_size > arg_process_size_max) {
log_debug("Not generating stack trace: core size %"PRIu64" is greater "
"than %"PRIu64" (the configured maximum)",
coredump_size, arg_process_size_max);
if (!core_message)
} else
coredump_make_stack_trace(coredump_fd, context[CONTEXT_EXE], &stacktrace);
#endif
log:
core_message = strjoin("MESSAGE=Process ", context[CONTEXT_PID],
" (", context[CONTEXT_COMM], ") of user ",
context[CONTEXT_UID], " dumped core.",
journald_crash && filename ? "\nCoredump diverted to " : NULL,
journald_crash && filename ? filename : NULL);
core_message = strjoina("MESSAGE=Process ", context[CONTEXT_PID],
" (", context[CONTEXT_COMM], ") of user ",
context[CONTEXT_UID], " dumped core.",
journald_crash && filename ? "\nCoredump diverted to " : NULL,
journald_crash && filename ? filename : NULL);
core_message = strjoin(core_message, stacktrace ? "\n\n" : NULL, stacktrace);
if (!core_message)
return log_oom();

12
src/coredump/stacktrace.c
View File

@ -108,7 +108,7 @@ static int thread_callback(Dwfl_Thread *thread, void *userdata) {
return DWARF_CB_OK;
}
int coredump_make_stack_trace(int fd, const char *executable, char **ret) {
static int make_stack_trace(int fd, const char *executable, char **ret) {
static const Dwfl_Callbacks callbacks = {
.find_elf = dwfl_build_id_find_elf,
@ -183,3 +183,13 @@ finish:
return r;
}
void coredump_make_stack_trace(int fd, const char *executable, char **ret) {
int r;
r = make_stack_trace(fd, executable, ret);
if (r == -EINVAL)
log_warning("Failed to generate stack trace: %s", dwfl_errmsg(dwfl_errno()));
else if (r < 0)
log_warning_errno(r, "Failed to generate stack trace: %m");
}

2
src/coredump/stacktrace.h
View File

@ -1,4 +1,4 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
int coredump_make_stack_trace(int fd, const char *executable, char **ret);
void coredump_make_stack_trace(int fd, const char *executable, char **ret);