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core: various cleanups for setup_input/output (#39860)

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This commit is contained in:
Mike Yuan
2025-12-18 15:56:42 +01:00
committed by GitHub
parent 6e44160e0f 7498c391ec
commit 4a6e5b0ae9
6 changed files with 175 additions and 192 deletions
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src/core/dbus-execute.c
+7 -9
View File
@@ -3338,17 +3338,15 @@ int bus_exec_context_set_transient_property(
if (r < 0)
return r;
if (!isempty(s)) {
if (!path_is_absolute(s))
return sd_bus_error_setf(reterr_error, SD_BUS_ERROR_INVALID_ARGS, "Path %s is not absolute", s);
if (!path_is_normalized(s))
return sd_bus_error_setf(reterr_error, SD_BUS_ERROR_INVALID_ARGS, "Path %s is not normalized", s);
}
if (!path_is_absolute(s))
return sd_bus_error_setf(reterr_error, SD_BUS_ERROR_INVALID_ARGS, "Path %s is not absolute", s);
if (!path_is_normalized(s))
return sd_bus_error_setf(reterr_error, SD_BUS_ERROR_INVALID_ARGS, "Path %s is not normalized", s);
if (!UNIT_WRITE_FLAGS_NOOP(flags)) {
if (streq(name, "StandardInputFile")) {
r = free_and_strdup(&c->stdio_file[STDIN_FILENO], empty_to_null(s));
r = free_and_strdup(&c->stdio_file[STDIN_FILENO], s);
if (r < 0)
return r;
@@ -3356,7 +3354,7 @@ int bus_exec_context_set_transient_property(
unit_write_settingf(u, flags|UNIT_ESCAPE_SPECIFIERS, name, "StandardInput=file:%s", s);
} else if (STR_IN_SET(name, "StandardOutputFile", "StandardOutputFileToAppend", "StandardOutputFileToTruncate")) {
r = free_and_strdup(&c->stdio_file[STDOUT_FILENO], empty_to_null(s));
r = free_and_strdup(&c->stdio_file[STDOUT_FILENO], s);
if (r < 0)
return r;
@@ -3374,7 +3372,7 @@ int bus_exec_context_set_transient_property(
} else {
assert(STR_IN_SET(name, "StandardErrorFile", "StandardErrorFileToAppend", "StandardErrorFileToTruncate"));
r = free_and_strdup(&c->stdio_file[STDERR_FILENO], empty_to_null(s));
r = free_and_strdup(&c->stdio_file[STDERR_FILENO], s);
if (r < 0)
return r;
src/core/exec-invoke.c
+76 -77
View File
@@ -308,7 +308,6 @@ static int acquire_path(const char *path, int flags, mode_t mode) {
static int fixup_input(
const ExecContext *context,
int socket_fd,
bool apply_tty_stdin) {
ExecInput std_input;
@@ -320,23 +319,12 @@ static int fixup_input(
if (exec_input_is_terminal(std_input) && !apply_tty_stdin)
return EXEC_INPUT_NULL;
if (std_input == EXEC_INPUT_SOCKET && socket_fd < 0)
return EXEC_INPUT_NULL;
if (std_input == EXEC_INPUT_DATA && context->stdin_data_size == 0)
return EXEC_INPUT_NULL;
return std_input;
}
static int fixup_output(ExecOutput output, int socket_fd) {
if (output == EXEC_OUTPUT_SOCKET && socket_fd < 0)
return EXEC_OUTPUT_INHERIT;
return output;
}
static int setup_input(
const ExecContext *context,
const ExecParameters *params,
@@ -361,7 +349,7 @@ static int setup_input(
return STDIN_FILENO;
}
i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
i = fixup_input(context, params->flags & EXEC_APPLY_TTY_STDIN);
switch (i) {
@@ -430,8 +418,8 @@ static int setup_input(
assert(context->stdio_file[STDIN_FILENO]);
rw = (context->std_output == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDOUT_FILENO])) ||
(context->std_error == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDERR_FILENO]));
rw = (context->std_output == EXEC_OUTPUT_FILE && path_equal(context->stdio_file[STDIN_FILENO], context->stdio_file[STDOUT_FILENO])) ||
(context->std_error == EXEC_OUTPUT_FILE && path_equal(context->stdio_file[STDIN_FILENO], context->stdio_file[STDERR_FILENO]));
fd = acquire_path(context->stdio_file[STDIN_FILENO], rw ? O_RDWR : O_RDONLY, 0666 & ~context->umask);
if (fd < 0)
@@ -445,30 +433,68 @@ static int setup_input(
}
}
static bool can_inherit_stderr_from_stdout(
const ExecContext *context,
ExecOutput o,
ExecOutput e) {
static bool can_inherit_stderr_from_stdout(const ExecContext *context) {
ExecOutput o, e;
assert(context);
/* Returns true, if given the specified STDERR and STDOUT output we can directly dup() the stdout fd to the
* stderr fd */
o = context->std_output;
e = context->std_error;
if (e == EXEC_OUTPUT_INHERIT)
return true;
if (e != o)
return false;
/* Let's not shortcut named fds here, even though we in theory can by comparing fd names, since
* we have the named_iofds array readily available, and the inherit practice would simply be duplicative. */
if (e == EXEC_OUTPUT_NAMED_FD)
return streq_ptr(context->stdio_fdname[STDOUT_FILENO], context->stdio_fdname[STDERR_FILENO]);
return false;
if (IN_SET(e, EXEC_OUTPUT_FILE, EXEC_OUTPUT_FILE_APPEND, EXEC_OUTPUT_FILE_TRUNCATE))
return streq_ptr(context->stdio_file[STDOUT_FILENO], context->stdio_file[STDERR_FILENO]);
return path_equal(context->stdio_file[STDOUT_FILENO], context->stdio_file[STDERR_FILENO]);
return true;
}
static int maybe_inherit_stdout_from_stdin(const ExecContext *context, ExecInput i) {
int r;
assert(context);
if (context->std_output != EXEC_OUTPUT_INHERIT)
return 0;
/* If input got downgraded, inherit the original value */
if (i == EXEC_INPUT_NULL && exec_input_is_terminal(context->std_input))
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, STDOUT_FILENO);
if (!exec_input_is_inheritable(i))
goto fallback;
r = fd_is_writable(STDIN_FILENO);
if (r <= 0) {
if (r < 0)
log_warning_errno(r, "Failed to check if inherited stdin is writable for stdout, using fallback: %m");
else
log_warning("Inherited stdin is not writable for stdout, using fallback: %m");
goto fallback;
}
return RET_NERRNO(dup2(STDIN_FILENO, STDOUT_FILENO));
fallback:
/* If we are not started from PID 1 we just inherit STDOUT from our parent process. */
if (getppid() != 1)
return STDOUT_FILENO;
/* We need to open /dev/null here anew, to get the right access mode. */
return open_null_as(O_WRONLY, STDOUT_FILENO);
}
static int setup_output(
const ExecContext *context,
const ExecParameters *params,
@@ -506,65 +532,33 @@ static int setup_output(
return STDERR_FILENO;
}
i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
o = fixup_output(context->std_output, socket_fd);
i = fixup_input(context, params->flags & EXEC_APPLY_TTY_STDIN);
if (fileno == STDERR_FILENO) {
ExecOutput e;
e = fixup_output(context->std_error, socket_fd);
/* This expects the input and output are already set up */
/* Don't change the stderr file descriptor if we inherit all
* the way and are not on a tty */
if (e == EXEC_OUTPUT_INHERIT &&
o == EXEC_OUTPUT_INHERIT &&
i == EXEC_INPUT_NULL &&
!exec_input_is_terminal(context->std_input) &&
if (context->std_error == EXEC_OUTPUT_INHERIT &&
context->std_output == EXEC_OUTPUT_INHERIT &&
i == EXEC_INPUT_NULL && !exec_input_is_terminal(context->std_input) &&
getppid() != 1)
return fileno;
/* Duplicate from stdout if possible */
if (can_inherit_stderr_from_stdout(context, o, e)) {
r = fd_is_writable(STDOUT_FILENO);
if (r <= 0) {
if (r < 0)
log_warning_errno(r, "Failed to check if inherited stdout is writable for stderr, falling back to /dev/null.");
else
log_warning("Inherited stdout is not writable for stderr, falling back to /dev/null.");
return open_null_as(O_WRONLY, fileno);
}
if (can_inherit_stderr_from_stdout(context))
return RET_NERRNO(dup2(STDOUT_FILENO, fileno));
}
o = e;
o = context->std_error;
} else if (o == EXEC_OUTPUT_INHERIT) {
/* If input got downgraded, inherit the original value */
if (i == EXEC_INPUT_NULL && exec_input_is_terminal(context->std_input))
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
} else {
assert(fileno == STDOUT_FILENO);
/* If the input is connected to anything that's not a /dev/null or a data fd, inherit that... */
if (!IN_SET(i, EXEC_INPUT_NULL, EXEC_INPUT_DATA)) {
r = fd_is_writable(STDIN_FILENO);
if (r <= 0) {
if (r < 0)
log_warning_errno(r, "Failed to check if inherited stdin is writable for %s, falling back to /dev/null.",
fileno == STDOUT_FILENO ? "stdout" : "stderr");
else
log_warning("Inherited stdin is not writable for %s, falling back to /dev/null.",
fileno == STDOUT_FILENO ? "stdout" : "stderr");
return open_null_as(O_WRONLY, fileno);
}
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
}
r = maybe_inherit_stdout_from_stdin(context, i);
if (r != 0)
return r;
/* If we are not started from PID 1 we just inherit STDOUT from our parent process. */
if (getppid() != 1)
return fileno;
/* We need to open /dev/null here anew, to get the right access mode. */
return open_null_as(O_WRONLY, fileno);
o = context->std_output;
}
switch (o) {
@@ -630,15 +624,14 @@ static int setup_output(
case EXEC_OUTPUT_FILE:
case EXEC_OUTPUT_FILE_APPEND:
case EXEC_OUTPUT_FILE_TRUNCATE: {
bool rw;
int fd, flags;
assert(context->stdio_file[fileno]);
rw = context->std_input == EXEC_INPUT_FILE &&
streq_ptr(context->stdio_file[fileno], context->stdio_file[STDIN_FILENO]);
if (rw)
/* stdin points to the same file hence setup_input() opened it as rw already?
* Then just duplicate it. */
if (context->std_input == EXEC_INPUT_FILE &&
path_equal(context->stdio_file[fileno], context->stdio_file[STDIN_FILENO]))
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
flags = O_WRONLY;
@@ -4794,28 +4787,34 @@ static int exec_context_named_iofds(
/* Note that socket fds are always placed at the beginning of the fds array, no need for extra
* manipulation. */
for (size_t i = 0; i < p->n_socket_fds && targets > 0; i++)
for (size_t i = 0; i < p->n_socket_fds && targets > 0; i++) {
if (named_iofds[STDIN_FILENO] < 0 &&
c->std_input == EXEC_INPUT_NAMED_FD &&
streq(p->fd_names[i], stdio_fdname[STDIN_FILENO])) {
named_iofds[STDIN_FILENO] = p->fds[i];
targets--;
continue;
}
} else if (named_iofds[STDOUT_FILENO] < 0 &&
c->std_output == EXEC_OUTPUT_NAMED_FD &&
streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) {
/* Allow stdout and stderr to use the same named fd */
if (named_iofds[STDOUT_FILENO] < 0 &&
c->std_output == EXEC_OUTPUT_NAMED_FD &&
streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) {
named_iofds[STDOUT_FILENO] = p->fds[i];
targets--;
}
} else if (named_iofds[STDERR_FILENO] < 0 &&
c->std_error == EXEC_OUTPUT_NAMED_FD &&
streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) {
if (named_iofds[STDERR_FILENO] < 0 &&
c->std_error == EXEC_OUTPUT_NAMED_FD &&
streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) {
named_iofds[STDERR_FILENO] = p->fds[i];
targets--;
}
}
return targets == 0 ? 0 : -ENOENT;
}
src/core/execute-serialize.c
+78 -90
View File
@@ -1539,48 +1539,6 @@ static int exec_parameters_deserialize(ExecParameters *p, FILE *f, FDSet *fds) {
return 0;
}
static int serialize_std_out_err(const ExecContext *c, FILE *f, int fileno) {
char *key, *value;
const char *type;
assert(c);
assert(f);
assert(IN_SET(fileno, STDOUT_FILENO, STDERR_FILENO));
type = fileno == STDOUT_FILENO ? "output" : "error";
switch (fileno == STDOUT_FILENO ? c->std_output : c->std_error) {
case EXEC_OUTPUT_NAMED_FD:
key = strjoina("exec-context-std-", type, "-fd-name");
value = c->stdio_fdname[fileno];
break;
case EXEC_OUTPUT_FILE:
key = strjoina("exec-context-std-", type, "-file");
value = c->stdio_file[fileno];
break;
case EXEC_OUTPUT_FILE_APPEND:
key = strjoina("exec-context-std-", type, "-file-append");
value = c->stdio_file[fileno];
break;
case EXEC_OUTPUT_FILE_TRUNCATE:
key = strjoina("exec-context-std-", type, "-file-truncate");
value = c->stdio_file[fileno];
break;
default:
return 0;
}
return serialize_item(f, key, value);
}
static int exec_context_serialize(const ExecContext *c, FILE *f) {
int r;
@@ -2004,6 +1962,10 @@ static int exec_context_serialize(const ExecContext *c, FILE *f) {
return r;
}
r = serialize_bool_elide(f, "exec-context-root-directory-as-fd", c->root_directory_as_fd);
if (r < 0)
return r;
r = serialize_item(f, "exec-context-std-input", exec_input_to_string(c->std_input));
if (r < 0)
return r;
@@ -2020,36 +1982,60 @@ static int exec_context_serialize(const ExecContext *c, FILE *f) {
if (r < 0)
return r;
r = serialize_bool_elide(f, "exec-context-root-directory-as-fd", c->root_directory_as_fd);
if (r < 0)
return r;
switch (c->std_input) {
case EXEC_INPUT_NAMED_FD:
r = serialize_item(f, "exec-context-std-input-fd-name", c->stdio_fdname[STDIN_FILENO]);
if (r < 0)
return r;
break;
case EXEC_INPUT_FILE:
r = serialize_item(f, "exec-context-std-input-file", c->stdio_file[STDIN_FILENO]);
if (r < 0)
return r;
r = serialize_item_escaped(f, "exec-context-std-input-file", c->stdio_file[STDIN_FILENO]);
break;
case EXEC_INPUT_DATA:
r = serialize_item_base64mem(f, "exec-context-std-input-data", c->stdin_data, c->stdin_data_size);
break;
default:
;
r = 0;
}
r = serialize_std_out_err(c, f, STDOUT_FILENO);
if (r < 0)
return r;
r = serialize_std_out_err(c, f, STDERR_FILENO);
switch (c->std_output) {
case EXEC_OUTPUT_NAMED_FD:
r = serialize_item(f, "exec-context-std-output-fd-name", c->stdio_fdname[STDOUT_FILENO]);
break;
case EXEC_OUTPUT_FILE:
case EXEC_OUTPUT_FILE_APPEND:
case EXEC_OUTPUT_FILE_TRUNCATE:
r = serialize_item_escaped(f, "exec-context-std-output-file", c->stdio_file[STDOUT_FILENO]);
break;
default:
r = 0;
}
if (r < 0)
return r;
r = serialize_item_base64mem(f, "exec-context-stdin-data", c->stdin_data, c->stdin_data_size);
switch (c->std_error) {
case EXEC_OUTPUT_NAMED_FD:
r = serialize_item(f, "exec-context-std-error-fd-name", c->stdio_fdname[STDERR_FILENO]);
break;
case EXEC_OUTPUT_FILE:
case EXEC_OUTPUT_FILE_APPEND:
case EXEC_OUTPUT_FILE_TRUNCATE:
r = serialize_item_escaped(f, "exec-context-std-error-file", c->stdio_file[STDERR_FILENO]);
break;
default:
r = 0;
}
if (r < 0)
return r;
@@ -3017,6 +3003,11 @@ static int exec_context_deserialize(ExecContext *c, FILE *f) {
r = deserialize_usec(val, (usec_t *)&c->timer_slack_nsec);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-root-directory-as-fd="))) {
r = parse_boolean(val);
if (r < 0)
return r;
c->root_directory_as_fd = r;
} else if ((val = startswith(l, "exec-context-std-input="))) {
c->std_input = exec_input_from_string(val);
if (c->std_input < 0)
@@ -3034,11 +3025,13 @@ static int exec_context_deserialize(ExecContext *c, FILE *f) {
if (r < 0)
return r;
c->stdio_as_fds = r;
} else if ((val = startswith(l, "exec-context-root-directory-as-fd="))) {
r = parse_boolean(val);
} else if ((val = startswith(l, "exec-context-std-input-data="))) {
if (c->stdin_data)
return -EINVAL; /* duplicated */
r = unbase64mem(val, &c->stdin_data, &c->stdin_data_size);
if (r < 0)
return r;
c->root_directory_as_fd = r;
} else if ((val = startswith(l, "exec-context-std-input-fd-name="))) {
r = free_and_strdup(&c->stdio_fdname[STDIN_FILENO], val);
if (r < 0)
@@ -3052,40 +3045,35 @@ static int exec_context_deserialize(ExecContext *c, FILE *f) {
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-std-input-file="))) {
r = free_and_strdup(&c->stdio_file[STDIN_FILENO], val);
if (r < 0)
return r;
ssize_t k;
char *p;
k = cunescape(val, 0, &p);
if (k < 0)
return k;
free_and_replace(c->stdio_file[STDIN_FILENO], p);
} else if ((val = startswith(l, "exec-context-std-output-file="))) {
r = free_and_strdup(&c->stdio_file[STDOUT_FILENO], val);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-std-output-file-append="))) {
r = free_and_strdup(&c->stdio_file[STDOUT_FILENO], val);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-std-output-file-truncate="))) {
r = free_and_strdup(&c->stdio_file[STDOUT_FILENO], val);
if (r < 0)
return r;
ssize_t k;
char *p;
k = cunescape(val, 0, &p);
if (k < 0)
return k;
free_and_replace(c->stdio_file[STDOUT_FILENO], p);
} else if ((val = startswith(l, "exec-context-std-error-file="))) {
r = free_and_strdup(&c->stdio_file[STDERR_FILENO], val);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-std-error-file-append="))) {
r = free_and_strdup(&c->stdio_file[STDERR_FILENO], val);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-std-error-file-truncate="))) {
r = free_and_strdup(&c->stdio_file[STDERR_FILENO], val);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-stdin-data="))) {
if (c->stdin_data)
return -EINVAL; /* duplicated */
ssize_t k;
char *p;
k = cunescape(val, 0, &p);
if (k < 0)
return k;
free_and_replace(c->stdio_file[STDERR_FILENO], p);
r = unbase64mem(val, &c->stdin_data, &c->stdin_data_size);
if (r < 0)
return r;
} else if ((val = startswith(l, "exec-context-tty-path="))) {
r = free_and_strdup(&c->tty_path, val);
if (r < 0)
src/core/execute.h
+10
View File
@@ -480,6 +480,16 @@ static inline bool exec_context_has_tty(const ExecContext *context) {
context->std_error == EXEC_OUTPUT_TTY;
}
static inline bool exec_input_is_inheritable(ExecInput i) {
/* We assume these listed inputs refer to bidirectional streams, and hence duplicating them from
* stdin to stdout/stderr makes sense and hence allowing EXEC_OUTPUT_INHERIT makes sense, too.
* Outputs such as regular files or sealed data memfds otoh don't really make sense to be
* duplicated for both input and output at the same time (since they then would cause a feedback
* loop). */
return exec_input_is_terminal(i) || IN_SET(i, EXEC_INPUT_SOCKET, EXEC_INPUT_NAMED_FD);
}
int exec_spawn(
Unit *unit,
ExecCommand *command,
src/core/service.c
+3 -11
View File
@@ -808,19 +808,11 @@ static void service_fix_stdio(Service *s) {
s->exec_context.stdin_data_size > 0)
s->exec_context.std_input = EXEC_INPUT_DATA;
if (IN_SET(s->exec_context.std_input,
EXEC_INPUT_TTY,
EXEC_INPUT_TTY_FORCE,
EXEC_INPUT_TTY_FAIL,
EXEC_INPUT_SOCKET,
EXEC_INPUT_NAMED_FD))
if (exec_input_is_inheritable(s->exec_context.std_input))
return;
/* We assume these listed inputs refer to bidirectional streams, and hence duplicating them from
* stdin to stdout/stderr makes sense and hence leaving EXEC_OUTPUT_INHERIT in place makes sense,
* too. Outputs such as regular files or sealed data memfds otoh don't really make sense to be
* duplicated for both input and output at the same time (since they then would cause a feedback
* loop), hence override EXEC_OUTPUT_INHERIT with the default stderr/stdout setting. */
/* Override EXEC_OUTPUT_INHERIT with the default stderr/stdout setting if not applicable for
* given stdin mode. */
if (s->exec_context.std_error == EXEC_OUTPUT_INHERIT &&
s->exec_context.std_output == EXEC_OUTPUT_INHERIT)
test/fuzz/fuzz-execute-serialize/initial
+1 -5
View File
@@ -63,14 +63,10 @@ exec-context-stdio-as-fds=
exec-context-std-input-fd-name=
exec-context-std-output-fd-name=
exec-context-std-error-fd-name=
exec-context-std-input-data=
exec-context-std-input-file=
exec-context-std-output-file=
exec-context-std-output-file-append=
exec-context-std-output-file-truncate=
exec-context-std-error-file=
exec-context-std-error-file-append=
exec-context-std-error-file-truncate=
exec-context-stdin-data=
exec-context-tty-path=
exec-context-tty-reset=
exec-context-tty-vhangup=