process-util.c revision a095315b3c31f7a419baceac82c26c3c5ac0cd12
/***
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 Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdbool.h>
#include <sys/types.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
#include <ctype.h>
#include "fileio.h"
#include "util.h"
#include "log.h"
#include "signal-util.h"
#include "process-util.h"
int get_process_state(pid_t pid) {
const char *p;
char state;
int r;
_cleanup_free_ char *line = NULL;
assert(pid >= 0);
p = procfs_file_alloca(pid, "stat");
r = read_one_line_file(p, &line);
if (r < 0)
return r;
p = strrchr(line, ')');
if (!p)
return -EIO;
p++;
if (sscanf(p, " %c", &state) != 1)
return -EIO;
return (unsigned char) state;
}
int get_process_comm(pid_t pid, char **name) {
const char *p;
int r;
assert(name);
assert(pid >= 0);
p = procfs_file_alloca(pid, "comm");
r = read_one_line_file(p, name);
if (r == -ENOENT)
return -ESRCH;
return r;
}
int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) {
_cleanup_fclose_ FILE *f = NULL;
char *r = NULL, *k;
const char *p;
int c;
assert(line);
assert(pid >= 0);
p = procfs_file_alloca(pid, "cmdline");
f = fopen(p, "re");
if (!f)
return -errno;
if (max_length == 0) {
size_t len = 0, allocated = 0;
while ((c = getc(f)) != EOF) {
if (!GREEDY_REALLOC(r, allocated, len+2)) {
free(r);
return -ENOMEM;
}
r[len++] = isprint(c) ? c : ' ';
}
if (len > 0)
r[len-1] = 0;
} else {
bool space = false;
size_t left;
r = new(char, max_length);
if (!r)
return -ENOMEM;
k = r;
left = max_length;
while ((c = getc(f)) != EOF) {
if (isprint(c)) {
if (space) {
if (left <= 4)
break;
*(k++) = ' ';
left--;
space = false;
}
if (left <= 4)
break;
*(k++) = (char) c;
left--;
} else
space = true;
}
if (left <= 4) {
size_t n = MIN(left-1, 3U);
memcpy(k, "...", n);
k[n] = 0;
} else
*k = 0;
}
/* Kernel threads have no argv[] */
if (isempty(r)) {
_cleanup_free_ char *t = NULL;
int h;
free(r);
if (!comm_fallback)
return -ENOENT;
h = get_process_comm(pid, &t);
if (h < 0)
return h;
r = strjoin("[", t, "]", NULL);
if (!r)
return -ENOMEM;
}
*line = r;
return 0;
}
int is_kernel_thread(pid_t pid) {
const char *p;
size_t count;
char c;
bool eof;
FILE *f;
if (pid == 0)
return 0;
assert(pid > 0);
p = procfs_file_alloca(pid, "cmdline");
f = fopen(p, "re");
if (!f)
return -errno;
count = fread(&c, 1, 1, f);
eof = feof(f);
fclose(f);
/* Kernel threads have an empty cmdline */
if (count <= 0)
return eof ? 1 : -errno;
return 0;
}
int get_process_capeff(pid_t pid, char **capeff) {
const char *p;
assert(capeff);
assert(pid >= 0);
p = procfs_file_alloca(pid, "status");
return get_status_field(p, "\nCapEff:", capeff);
}
static int get_process_link_contents(const char *proc_file, char **name) {
int r;
assert(proc_file);
assert(name);
r = readlink_malloc(proc_file, name);
if (r < 0)
return r == -ENOENT ? -ESRCH : r;
return 0;
}
int get_process_exe(pid_t pid, char **name) {
const char *p;
char *d;
int r;
assert(pid >= 0);
p = procfs_file_alloca(pid, "exe");
r = get_process_link_contents(p, name);
if (r < 0)
return r;
d = endswith(*name, " (deleted)");
if (d)
*d = '\0';
return 0;
}
static int get_process_id(pid_t pid, const char *field, uid_t *uid) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
const char *p;
assert(field);
assert(uid);
if (pid == 0)
return getuid();
p = procfs_file_alloca(pid, "status");
f = fopen(p, "re");
if (!f)
return -errno;
FOREACH_LINE(line, f, return -errno) {
char *l;
l = strstrip(line);
if (startswith(l, field)) {
l += strlen(field);
l += strspn(l, WHITESPACE);
l[strcspn(l, WHITESPACE)] = 0;
return parse_uid(l, uid);
}
}
return -EIO;
}
int get_process_uid(pid_t pid, uid_t *uid) {
return get_process_id(pid, "Uid:", uid);
}
int get_process_gid(pid_t pid, gid_t *gid) {
assert_cc(sizeof(uid_t) == sizeof(gid_t));
return get_process_id(pid, "Gid:", gid);
}
int get_process_cwd(pid_t pid, char **cwd) {
const char *p;
assert(pid >= 0);
p = procfs_file_alloca(pid, "cwd");
return get_process_link_contents(p, cwd);
}
int get_process_root(pid_t pid, char **root) {
const char *p;
assert(pid >= 0);
p = procfs_file_alloca(pid, "root");
return get_process_link_contents(p, root);
}
int get_process_environ(pid_t pid, char **env) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *outcome = NULL;
int c;
const char *p;
size_t allocated = 0, sz = 0;
assert(pid >= 0);
assert(env);
p = procfs_file_alloca(pid, "environ");
f = fopen(p, "re");
if (!f)
return -errno;
while ((c = fgetc(f)) != EOF) {
if (!GREEDY_REALLOC(outcome, allocated, sz + 5))
return -ENOMEM;
if (c == '\0')
outcome[sz++] = '\n';
else
sz += cescape_char(c, outcome + sz);
}
outcome[sz] = '\0';
*env = outcome;
outcome = NULL;
return 0;
}
int get_parent_of_pid(pid_t pid, pid_t *_ppid) {
int r;
_cleanup_free_ char *line = NULL;
long unsigned ppid;
const char *p;
assert(pid >= 0);
assert(_ppid);
if (pid == 0) {
*_ppid = getppid();
return 0;
}
p = procfs_file_alloca(pid, "stat");
r = read_one_line_file(p, &line);
if (r < 0)
return r;
/* Let's skip the pid and comm fields. The latter is enclosed
* in () but does not escape any () in its value, so let's
* skip over it manually */
p = strrchr(line, ')');
if (!p)
return -EIO;
p++;
if (sscanf(p, " "
"%*c " /* state */
"%lu ", /* ppid */
&ppid) != 1)
return -EIO;
if ((long unsigned) (pid_t) ppid != ppid)
return -ERANGE;
*_ppid = (pid_t) ppid;
return 0;
}
int wait_for_terminate(pid_t pid, siginfo_t *status) {
siginfo_t dummy;
assert(pid >= 1);
if (!status)
status = &dummy;
for (;;) {
zero(*status);
if (waitid(P_PID, pid, status, WEXITED) < 0) {
if (errno == EINTR)
continue;
return -errno;
}
return 0;
}
}
/*
* Return values:
* < 0 : wait_for_terminate() failed to get the state of the
* process, the process was terminated by a signal, or
* failed for an unknown reason.
* >=0 : The process terminated normally, and its exit code is
* returned.
*
* That is, success is indicated by a return value of zero, and an
* error is indicated by a non-zero value.
*
* A warning is emitted if the process terminates abnormally,
* and also if it returns non-zero unless check_exit_code is true.
*/
int wait_for_terminate_and_warn(const char *name, pid_t pid, bool check_exit_code) {
int r;
siginfo_t status;
assert(name);
assert(pid > 1);
r = wait_for_terminate(pid, &status);
if (r < 0)
return log_warning_errno(r, "Failed to wait for %s: %m", name);
if (status.si_code == CLD_EXITED) {
if (status.si_status != 0)
log_full(check_exit_code ? LOG_WARNING : LOG_DEBUG,
"%s failed with error code %i.", name, status.si_status);
else
log_debug("%s succeeded.", name);
return status.si_status;
} else if (status.si_code == CLD_KILLED ||
status.si_code == CLD_DUMPED) {
log_warning("%s terminated by signal %s.", name, signal_to_string(status.si_status));
return -EPROTO;
}
log_warning("%s failed due to unknown reason.", name);
return -EPROTO;
}
int kill_and_sigcont(pid_t pid, int sig) {
int r;
r = kill(pid, sig) < 0 ? -errno : 0;
if (r >= 0)
kill(pid, SIGCONT);
return r;
}
int getenv_for_pid(pid_t pid, const char *field, char **_value) {
_cleanup_fclose_ FILE *f = NULL;
char *value = NULL;
int r;
bool done = false;
size_t l;
const char *path;
assert(pid >= 0);
assert(field);
assert(_value);
path = procfs_file_alloca(pid, "environ");
f = fopen(path, "re");
if (!f)
return -errno;
l = strlen(field);
r = 0;
do {
char line[LINE_MAX];
unsigned i;
for (i = 0; i < sizeof(line)-1; i++) {
int c;
c = getc(f);
if (_unlikely_(c == EOF)) {
done = true;
break;
} else if (c == 0)
break;
line[i] = c;
}
line[i] = 0;
if (memcmp(line, field, l) == 0 && line[l] == '=') {
value = strdup(line + l + 1);
if (!value)
return -ENOMEM;
r = 1;
break;
}
} while (!done);
*_value = value;
return r;
}
bool pid_is_unwaited(pid_t pid) {
/* Checks whether a PID is still valid at all, including a zombie */
if (pid <= 0)
return false;
if (kill(pid, 0) >= 0)
return true;
return errno != ESRCH;
}
bool pid_is_alive(pid_t pid) {
int r;
/* Checks whether a PID is still valid and not a zombie */
if (pid <= 0)
return false;
r = get_process_state(pid);
if (r == -ENOENT || r == 'Z')
return false;
return true;
}