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Systemd/execute.c

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/*-*- Mode: C; c-basic-offset: 8 -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#pragma GCC diagnostic ignored "-Wattributes"
#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/prctl.h>
#include <linux/sched.h>
#include "execute.h"
#include "strv.h"
#include "macro.h"
#include "util.h"
#include "log.h"
#include "ioprio.h"
#include "securebits.h"
static int close_fds(int except[], unsigned n_except) {
DIR *d;
struct dirent *de;
int r = 0;
/* Modifies the fds array! (sorts it) */
if (!(d = opendir("/proc/self/fd")))
return -errno;
while ((de = readdir(d))) {
int fd;
if (de->d_name[0] == '.')
continue;
if ((r = safe_atoi(de->d_name, &fd)) < 0)
goto finish;
if (fd < 3)
continue;
if (fd == dirfd(d))
continue;
if (except) {
bool found;
unsigned i;
found = false;
for (i = 0; i < n_except; i++)
if (except[i] == fd) {
found = true;
break;
}
if (found)
continue;
}
if ((r = close_nointr(fd)) < 0)
goto finish;
}
finish:
closedir(d);
return r;
}
static int shift_fds(int fds[], unsigned n_fds) {
int start, restart_from;
if (n_fds <= 0)
return 0;
assert(fds);
start = 0;
for (;;) {
int i;
restart_from = -1;
for (i = start; i < (int) n_fds; i++) {
int nfd;
/* Already at right index? */
if (fds[i] == i+3)
continue;
if ((nfd = fcntl(fds[i], F_DUPFD, i+3)) < 0)
return -errno;
assert_se(close_nointr(fds[i]) == 0);
fds[i] = nfd;
/* Hmm, the fd we wanted isn't free? Then
* let's remember that and try again from here*/
if (nfd != i+3 && restart_from < 0)
restart_from = i;
}
if (restart_from < 0)
break;
start = restart_from;
}
return 0;
}
static int flags_fds(int fds[], unsigned n_fds) {
unsigned i;
if (n_fds <= 0)
return 0;
assert(fds);
/* Drops O_NONBLOCK and FD_CLOEXEC from the file flags */
for (i = 0; i < n_fds; i++) {
int flags;
if ((flags = fcntl(fds[i], F_GETFL, 0)) < 0)
return -errno;
/* Since we are at it, let's make sure that nobody
* forgot setting O_NONBLOCK for all our fds */
if (fcntl(fds[i], F_SETFL, flags &~O_NONBLOCK) < 0)
return -errno;
if ((flags = fcntl(fds[i], F_GETFD, 0)) < 0)
return -errno;
/* Also make sure nobody forgot O_CLOEXEC for all our
* fds */
if (fcntl(fds[i], F_SETFD, flags &~FD_CLOEXEC) < 0)
return -errno;
}
return 0;
}
static int replace_null_fd(int fd, int flags) {
int nfd;
assert(fd >= 0);
close_nointr(fd);
if ((nfd = open("/dev/null", flags|O_NOCTTY)) < 0)
return -errno;
if (nfd != fd) {
close_nointr_nofail(nfd);
return -EIO;
}
return 0;
}
static int setup_output(const ExecContext *context, const char *ident) {
int r;
assert(context);
switch (context->output) {
case EXEC_OUTPUT_CONSOLE:
return 0;
case EXEC_OUTPUT_NULL:
if ((r = replace_null_fd(STDOUT_FILENO, O_WRONLY)) < 0 ||
(r = replace_null_fd(STDERR_FILENO, O_WRONLY)) < 0)
return r;
return 0;
case EXEC_OUTPUT_KERNEL:
case EXEC_OUTPUT_SYSLOG: {
int fd;
union {
struct sockaddr sa;
struct sockaddr_un un;
} sa;
close_nointr(STDOUT_FILENO);
close_nointr(STDERR_FILENO);
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
return -errno;
if (fd != STDOUT_FILENO) {
close_nointr_nofail(fd);
return -EIO;
}
zero(sa);
sa.sa.sa_family = AF_UNIX;
strncpy(sa.un.sun_path+1, LOGGER_SOCKET, sizeof(sa.un.sun_path)-1);
if (connect(fd, &sa.sa, sizeof(sa)) < 0) {
close_nointr_nofail(fd);
return -errno;
}
if (shutdown(fd, SHUT_RD) < 0) {
close_nointr_nofail(fd);
return -errno;
}
if ((fd = dup(fd)) < 0) {
close_nointr_nofail(fd);
return -errno;
}
if (fd != STDERR_FILENO) {
close_nointr_nofail(fd);
return -EIO;
}
/* We speak a very simple protocol between log server
* and client: one line for the log destination (kmsg
* or syslog), followed by the priority field,
* followed by the process name. Since we replaced
* stdin/stderr we simple use stdio to write to
* it. Note that we use stderr, to minimize buffer
* flushing issues. */
fprintf(stderr,
"%s\n"
"%i\n"
"%s\n",
context->output == EXEC_OUTPUT_KERNEL ? "kmsg" : "syslog",
context->syslog_priority,
context->syslog_identifier ? context->syslog_identifier : ident);
return 0;
}
default:
assert_not_reached("Unknown output type");
}
}
static int setup_input(const ExecContext *context) {
int r;
assert(context);
switch (context->input) {
case EXEC_INPUT_CONSOLE:
return 0;
case EXEC_INPUT_NULL:
if ((r = replace_null_fd(STDIN_FILENO, O_RDONLY)) < 0)
return r;
return 0;
default:
assert_not_reached("Unknown input type");
}
}
int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds, unsigned n_fds, pid_t *ret) {
pid_t pid;
assert(command);
assert(context);
assert(ret);
assert(fds || n_fds <= 0);
log_debug("about to execute %s", command->path);
if ((pid = fork()) < 0)
return -errno;
if (pid == 0) {
char **e, **f = NULL;
int i, r;
sigset_t ss;
/* child */
if (sigemptyset(&ss) < 0 ||
sigprocmask(SIG_SETMASK, &ss, NULL) < 0) {
r = EXIT_SIGNAL_MASK;
goto fail;
}
if (setpgid(0, 0) < 0) {
r = EXIT_PGID;
goto fail;
}
umask(context->umask);
if (setup_input(context) < 0) {
r = EXIT_INPUT;
goto fail;
}
if (setup_output(context, file_name_from_path(command->path)) < 0) {
r = EXIT_OUTPUT;
goto fail;
}
if (context->oom_adjust_set) {
char t[16];
snprintf(t, sizeof(t), "%i", context->oom_adjust);
char_array_0(t);
if (write_one_line_file("/proc/self/oom_adj", t) < 0) {
r = EXIT_OOM_ADJUST;
goto fail;
}
}
if (context->root_directory)
if (chroot(context->root_directory) < 0) {
r = EXIT_CHROOT;
goto fail;
}
if (chdir(context->working_directory ? context->working_directory : "/") < 0) {
r = EXIT_CHDIR;
goto fail;
}
if (context->nice_set)
if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
r = EXIT_NICE;
goto fail;
}
if (context->cpu_sched_set) {
struct sched_param param;
zero(param);
param.sched_priority = context->cpu_sched_priority;
if (sched_setscheduler(0, context->cpu_sched_policy |
(context->cpu_sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0), &param) < 0) {
r = EXIT_SETSCHEDULER;
goto fail;
}
}
if (context->cpu_affinity_set)
if (sched_setaffinity(0, sizeof(context->cpu_affinity), &context->cpu_affinity) < 0) {
r = EXIT_CPUAFFINITY;
goto fail;
}
if (context->ioprio_set)
if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
r = EXIT_IOPRIO;
goto fail;
}
if (context->timer_slack_ns_set)
if (prctl(PR_SET_TIMERSLACK, context->timer_slack_ns_set) < 0) {
r = EXIT_TIMERSLACK;
goto fail;
}
if (close_fds(fds, n_fds) < 0 ||
shift_fds(fds, n_fds) < 0 ||
flags_fds(fds, n_fds) < 0) {
r = EXIT_FDS;
goto fail;
}
for (i = 0; i < RLIMIT_NLIMITS; i++) {
if (!context->rlimit[i])
continue;
if (setrlimit(i, context->rlimit[i]) < 0) {
r = EXIT_LIMITS;
goto fail;
}
}
if (context->secure_bits) {
if (prctl(PR_SET_SECUREBITS, context->secure_bits) < 0) {
r = EXIT_SECUREBITS;
goto fail;
}
}
if (n_fds > 0) {
char a[64], b[64];
char *listen_env[3] = {
a,
b,
NULL
};
snprintf(a, sizeof(a), "LISTEN_PID=%llu", (unsigned long long) getpid());
snprintf(b, sizeof(b), "LISTEN_FDS=%u", n_fds);
a[sizeof(a)-1] = 0;
b[sizeof(b)-1] = 0;
if (context->environment) {
if (!(f = strv_merge(listen_env, context->environment))) {
r = EXIT_MEMORY;
goto fail;
}
e = f;
} else
e = listen_env;
} else
e = context->environment;
execve(command->path, command->argv, e);
r = EXIT_EXEC;
fail:
strv_free(f);
_exit(r);
}
log_debug("executed %s as %llu", command->path, (unsigned long long) pid);
*ret = pid;
return 0;
}
void exec_context_init(ExecContext *c) {
assert(c);
c->umask = 0002;
c->oom_adjust = 0;
c->oom_adjust_set = false;
c->nice = 0;
c->nice_set = false;
c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
c->ioprio_set = false;
c->cpu_sched_policy = SCHED_OTHER;
c->cpu_sched_priority = 0;
c->cpu_sched_set = false;
CPU_ZERO(&c->cpu_affinity);
c->cpu_affinity_set = false;
c->input = 0;
c->output = 0;
c->syslog_priority = LOG_DAEMON|LOG_INFO;
c->secure_bits = 0;
c->capability_bounding_set_drop = 0;
}
void exec_context_done(ExecContext *c) {
unsigned l;
assert(c);
strv_free(c->environment);
c->environment = NULL;
for (l = 0; l < ELEMENTSOF(c->rlimit); l++) {
free(c->rlimit[l]);
c->rlimit[l] = NULL;
}
free(c->working_directory);
c->working_directory = NULL;
free(c->root_directory);
c->root_directory = NULL;
free(c->syslog_identifier);
c->syslog_identifier = NULL;
free(c->user);
c->user = NULL;
free(c->group);
c->group = NULL;
strv_free(c->supplementary_groups);
c->supplementary_groups = NULL;
if (c->capabilities) {
cap_free(c->capabilities);
c->capabilities = NULL;
}
}
void exec_command_free_list(ExecCommand *c) {
ExecCommand *i;
while ((i = c)) {
LIST_REMOVE(ExecCommand, command, c, i);
free(i->path);
strv_free(i->argv);
free(i);
}
}
void exec_command_free_array(ExecCommand **c, unsigned n) {
unsigned i;
for (i = 0; i < n; i++) {
exec_command_free_list(c[i]);
c[i] = NULL;
}
}
void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
char ** e;
unsigned i;
assert(c);
assert(f);
if (!prefix)
prefix = "";
fprintf(f,
"%sUMask: %04o\n"
"%sWorkingDirectory: %s\n"
"%sRootDirectory: %s\n",
prefix, c->umask,
prefix, c->working_directory ? c->working_directory : "/",
prefix, c->root_directory ? c->root_directory : "/");
if (c->environment)
for (e = c->environment; *e; e++)
fprintf(f, "%sEnvironment: %s\n", prefix, *e);
if (c->nice_set)
fprintf(f,
"%sNice: %i\n",
prefix, c->nice);
if (c->oom_adjust_set)
fprintf(f,
"%sOOMAdjust: %i\n",
prefix, c->oom_adjust);
for (i = 0; i < RLIM_NLIMITS; i++)
if (c->rlimit[i])
fprintf(f, "%s%s: %llu\n", prefix, rlimit_to_string(i), (unsigned long long) c->rlimit[i]->rlim_max);
if (c->ioprio_set)
fprintf(f,
"%sIOSchedulingClass: %s\n"
"%sIOPriority: %i\n",
prefix, ioprio_class_to_string(IOPRIO_PRIO_CLASS(c->ioprio)),
prefix, (int) IOPRIO_PRIO_DATA(c->ioprio));
if (c->cpu_sched_set)
fprintf(f,
"%sCPUSchedulingPolicy: %s\n"
"%sCPUSchedulingPriority: %i\n"
"%sCPUSchedulingResetOnFork: %s\n",
prefix, sched_policy_to_string(c->cpu_sched_policy),
prefix, c->cpu_sched_priority,
prefix, yes_no(c->cpu_sched_reset_on_fork));
if (c->cpu_affinity_set) {
fprintf(f, "%sCPUAffinity:", prefix);
for (i = 0; i < CPU_SETSIZE; i++)
if (CPU_ISSET(i, &c->cpu_affinity))
fprintf(f, " %i", i);
fputs("\n", f);
}
if (c->timer_slack_ns_set)
fprintf(f, "%sTimerSlackNS: %lu\n", prefix, c->timer_slack_ns);
fprintf(f,
"%sInput: %s\n"
"%sOutput: %s\n",
prefix, exec_input_to_string(c->input),
prefix, exec_output_to_string(c->output));
if (c->output == EXEC_OUTPUT_SYSLOG || c->output == EXEC_OUTPUT_KERNEL)
fprintf(f,
"%sSyslogFacility: %s\n"
"%sSyslogLevel: %s\n",
prefix, log_facility_to_string(LOG_FAC(c->syslog_priority)),
prefix, log_level_to_string(LOG_PRI(c->syslog_priority)));
if (c->capabilities) {
char *t;
if ((t = cap_to_text(c->capabilities, NULL))) {
fprintf(f, "%sCapabilities: %s\n",
prefix, t);
cap_free(t);
}
}
if (c->secure_bits)
fprintf(f, "%sSecure Bits:%s%s%s%s%s%s\n",
prefix,
(c->secure_bits & SECURE_KEEP_CAPS) ? " keep-caps" : "",
(c->secure_bits & SECURE_KEEP_CAPS_LOCKED) ? " keep-caps-locked" : "",
(c->secure_bits & SECURE_NO_SETUID_FIXUP) ? " no-setuid-fixup" : "",
(c->secure_bits & SECURE_NO_SETUID_FIXUP_LOCKED) ? " no-setuid-fixup-locked" : "",
(c->secure_bits & SECURE_NOROOT) ? " noroot" : "",
(c->secure_bits & SECURE_NOROOT_LOCKED) ? "noroot-locked" : "");
if (c->capability_bounding_set_drop) {
fprintf(f, "%sCapabilityBoundingSetDrop:", prefix);
for (i = 0; i <= CAP_LAST_CAP; i++)
if (c->capability_bounding_set_drop & (1 << i)) {
char *t;
if ((t = cap_to_name(i))) {
fprintf(f, " %s", t);
free(t);
}
}
fputs("\n", f);
}
if (c->user)
fprintf(f, "%sUser: %s", prefix, c->user);
if (c->group)
fprintf(f, "%sGroup: %s", prefix, c->group);
if (c->supplementary_groups) {
char **g;
fprintf(f, "%sSupplementaryGroups:", prefix);
STRV_FOREACH(g, c->supplementary_groups)
fprintf(f, " %s", *g);
fputs("\n", f);
}
}
void exec_status_fill(ExecStatus *s, pid_t pid, int code, int status) {
assert(s);
s->pid = pid;
s->code = code;
s->status = status;
s->timestamp = now(CLOCK_REALTIME);
}
char *exec_command_line(ExecCommand *c) {
size_t k;
char *n, *p, **a;
bool first = true;
assert(c);
assert(c->argv);
k = 1;
STRV_FOREACH(a, c->argv)
k += strlen(*a)+3;
if (!(n = new(char, k)))
return NULL;
p = n;
STRV_FOREACH(a, c->argv) {
if (!first)
*(p++) = ' ';
else
first = false;
if (strpbrk(*a, WHITESPACE)) {
*(p++) = '\'';
p = stpcpy(p, *a);
*(p++) = '\'';
} else
p = stpcpy(p, *a);
}
*p = 0;
/* FIXME: this doesn't really handle arguments that have
* spaces and ticks in them */
return n;
}
void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix) {
char *cmd;
assert(c);
assert(f);
if (!prefix)
prefix = "";
cmd = exec_command_line(c);
fprintf(f,
"%sCommand Line: %s\n",
prefix, cmd ? cmd : strerror(ENOMEM));
free(cmd);
}
void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) {
assert(f);
if (!prefix)
prefix = "";
LIST_FOREACH(command, c, c)
exec_command_dump(c, f, prefix);
}
static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = {
[EXEC_OUTPUT_CONSOLE] = "console",
[EXEC_OUTPUT_NULL] = "null",
[EXEC_OUTPUT_SYSLOG] = "syslog",
[EXEC_OUTPUT_KERNEL] = "kernel"
};
DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
static const char* const exec_input_table[_EXEC_INPUT_MAX] = {
[EXEC_INPUT_NULL] = "null",
[EXEC_INPUT_CONSOLE] = "console"
};
DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput);
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