6f8cbcdb27
When we are checking our own data, we can optimize things a bit.
1040 lines
30 KiB
C
1040 lines
30 KiB
C
/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#include <linux/oom.h>
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#include <sched.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/personality.h>
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#include <sys/prctl.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <syslog.h>
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#include <unistd.h>
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#ifdef HAVE_VALGRIND_VALGRIND_H
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#include <valgrind/valgrind.h>
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#endif
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#include "alloc-util.h"
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#include "architecture.h"
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#include "escape.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "ioprio.h"
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#include "log.h"
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#include "macro.h"
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#include "missing.h"
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#include "process-util.h"
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#include "raw-clone.h"
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#include "signal-util.h"
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#include "stat-util.h"
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#include "string-table.h"
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#include "string-util.h"
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#include "user-util.h"
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#include "util.h"
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int get_process_state(pid_t pid) {
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const char *p;
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char state;
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int r;
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_cleanup_free_ char *line = NULL;
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assert(pid >= 0);
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p = procfs_file_alloca(pid, "stat");
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r = read_one_line_file(p, &line);
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if (r == -ENOENT)
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return -ESRCH;
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if (r < 0)
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return r;
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p = strrchr(line, ')');
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if (!p)
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return -EIO;
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p++;
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if (sscanf(p, " %c", &state) != 1)
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return -EIO;
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return (unsigned char) state;
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}
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int get_process_comm(pid_t pid, char **name) {
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const char *p;
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int r;
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assert(name);
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assert(pid >= 0);
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p = procfs_file_alloca(pid, "comm");
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r = read_one_line_file(p, name);
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if (r == -ENOENT)
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return -ESRCH;
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return r;
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}
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int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) {
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_cleanup_fclose_ FILE *f = NULL;
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bool space = false;
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char *k, *ans = NULL;
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const char *p;
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int c;
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assert(line);
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assert(pid >= 0);
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/* Retrieves a process' command line. Replaces unprintable characters while doing so by whitespace (coalescing
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* multiple sequential ones into one). If max_length is != 0 will return a string of the specified size at most
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* (the trailing NUL byte does count towards the length here!), abbreviated with a "..." ellipsis. If
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* comm_fallback is true and the process has no command line set (the case for kernel threads), or has a
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* command line that resolves to the empty string will return the "comm" name of the process instead.
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*
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* Returns -ESRCH if the process doesn't exist, and -ENOENT if the process has no command line (and
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* comm_fallback is false). Returns 0 and sets *line otherwise. */
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p = procfs_file_alloca(pid, "cmdline");
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f = fopen(p, "re");
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if (!f) {
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if (errno == ENOENT)
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return -ESRCH;
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return -errno;
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}
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if (max_length == 1) {
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/* If there's only room for one byte, return the empty string */
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ans = new0(char, 1);
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if (!ans)
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return -ENOMEM;
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*line = ans;
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return 0;
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} else if (max_length == 0) {
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size_t len = 0, allocated = 0;
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while ((c = getc(f)) != EOF) {
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if (!GREEDY_REALLOC(ans, allocated, len+3)) {
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free(ans);
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return -ENOMEM;
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}
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if (isprint(c)) {
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if (space) {
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ans[len++] = ' ';
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space = false;
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}
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ans[len++] = c;
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} else if (len > 0)
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space = true;
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}
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if (len > 0)
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ans[len] = '\0';
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else
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ans = mfree(ans);
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} else {
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bool dotdotdot = false;
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size_t left;
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ans = new(char, max_length);
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if (!ans)
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return -ENOMEM;
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k = ans;
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left = max_length;
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while ((c = getc(f)) != EOF) {
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if (isprint(c)) {
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if (space) {
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if (left <= 2) {
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dotdotdot = true;
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break;
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}
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*(k++) = ' ';
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left--;
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space = false;
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}
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if (left <= 1) {
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dotdotdot = true;
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break;
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}
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*(k++) = (char) c;
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left--;
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} else if (k > ans)
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space = true;
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}
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if (dotdotdot) {
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if (max_length <= 4) {
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k = ans;
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left = max_length;
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} else {
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k = ans + max_length - 4;
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left = 4;
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/* Eat up final spaces */
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while (k > ans && isspace(k[-1])) {
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k--;
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left++;
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}
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}
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strncpy(k, "...", left-1);
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k[left-1] = 0;
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} else
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*k = 0;
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}
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/* Kernel threads have no argv[] */
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if (isempty(ans)) {
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_cleanup_free_ char *t = NULL;
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int h;
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free(ans);
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if (!comm_fallback)
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return -ENOENT;
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h = get_process_comm(pid, &t);
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if (h < 0)
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return h;
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if (max_length == 0)
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ans = strjoin("[", t, "]");
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else {
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size_t l;
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l = strlen(t);
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if (l + 3 <= max_length)
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ans = strjoin("[", t, "]");
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else if (max_length <= 6) {
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ans = new(char, max_length);
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if (!ans)
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return -ENOMEM;
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memcpy(ans, "[...]", max_length-1);
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ans[max_length-1] = 0;
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} else {
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char *e;
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t[max_length - 6] = 0;
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/* Chop off final spaces */
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e = strchr(t, 0);
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while (e > t && isspace(e[-1]))
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e--;
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*e = 0;
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ans = strjoin("[", t, "...]");
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}
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}
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if (!ans)
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return -ENOMEM;
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}
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*line = ans;
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return 0;
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}
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int rename_process(const char name[]) {
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static size_t mm_size = 0;
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static char *mm = NULL;
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bool truncated = false;
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size_t l;
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/* This is a like a poor man's setproctitle(). It changes the comm field, argv[0], and also the glibc's
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* internally used name of the process. For the first one a limit of 16 chars applies; to the second one in
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* many cases one of 10 (i.e. length of "/sbin/init") — however if we have CAP_SYS_RESOURCES it is unbounded;
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* to the third one 7 (i.e. the length of "systemd". If you pass a longer string it will likely be
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* truncated.
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*
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* Returns 0 if a name was set but truncated, > 0 if it was set but not truncated. */
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if (isempty(name))
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return -EINVAL; /* let's not confuse users unnecessarily with an empty name */
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l = strlen(name);
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/* First step, change the comm field. */
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(void) prctl(PR_SET_NAME, name);
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if (l > 15) /* Linux process names can be 15 chars at max */
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truncated = true;
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/* Second step, change glibc's ID of the process name. */
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if (program_invocation_name) {
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size_t k;
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k = strlen(program_invocation_name);
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strncpy(program_invocation_name, name, k);
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if (l > k)
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truncated = true;
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}
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/* Third step, completely replace the argv[] array the kernel maintains for us. This requires privileges, but
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* has the advantage that the argv[] array is exactly what we want it to be, and not filled up with zeros at
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* the end. This is the best option for changing /proc/self/cmdline. */
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if (mm_size < l+1) {
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size_t nn_size;
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char *nn;
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/* Let's not bother with this if we don't have euid == 0. Strictly speaking if people do weird stuff
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* with capabilities this could work even for euid != 0, but our own code generally doesn't do that,
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* hence let's use this as quick bypass check, to avoid calling mmap() if PR_SET_MM_ARG_START fails
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* with EPERM later on anyway. After all geteuid() is dead cheap to call, but mmap() is not. */
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if (geteuid() != 0) {
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log_debug("Skipping PR_SET_MM_ARG_START, as we don't have privileges.");
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goto use_saved_argv;
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}
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nn_size = PAGE_ALIGN(l+1);
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nn = mmap(NULL, nn_size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
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if (nn == MAP_FAILED) {
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log_debug_errno(errno, "mmap() failed: %m");
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goto use_saved_argv;
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}
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strncpy(nn, name, nn_size);
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/* Now, let's tell the kernel about this new memory */
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if (prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long) nn, 0, 0) < 0) {
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log_debug_errno(errno, "PR_SET_MM_ARG_START failed, proceeding without: %m");
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(void) munmap(nn, nn_size);
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goto use_saved_argv;
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}
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/* And update the end pointer to the new end, too. If this fails, we don't really know what to do, it's
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* pretty unlikely that we can rollback, hence we'll just accept the failure, and continue. */
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if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0)
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log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m");
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if (mm)
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(void) munmap(mm, mm_size);
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mm = nn;
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mm_size = nn_size;
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} else
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strncpy(mm, name, mm_size);
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use_saved_argv:
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/* Fourth step: in all cases we'll also update the original argv[], so that our own code gets it right too if
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* it still looks here */
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if (saved_argc > 0) {
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int i;
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if (saved_argv[0]) {
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size_t k;
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k = strlen(saved_argv[0]);
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strncpy(saved_argv[0], name, k);
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if (l > k)
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truncated = true;
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}
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for (i = 1; i < saved_argc; i++) {
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if (!saved_argv[i])
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break;
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memzero(saved_argv[i], strlen(saved_argv[i]));
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}
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}
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return !truncated;
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}
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int is_kernel_thread(pid_t pid) {
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const char *p;
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size_t count;
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char c;
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bool eof;
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FILE *f;
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if (pid == 0 || pid == 1 || pid == getpid_cached()) /* pid 1, and we ourselves certainly aren't a kernel thread */
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return 0;
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assert(pid > 1);
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p = procfs_file_alloca(pid, "cmdline");
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f = fopen(p, "re");
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if (!f) {
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if (errno == ENOENT)
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return -ESRCH;
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return -errno;
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}
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count = fread(&c, 1, 1, f);
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eof = feof(f);
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fclose(f);
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/* Kernel threads have an empty cmdline */
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if (count <= 0)
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return eof ? 1 : -errno;
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return 0;
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}
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int get_process_capeff(pid_t pid, char **capeff) {
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const char *p;
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int r;
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assert(capeff);
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assert(pid >= 0);
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p = procfs_file_alloca(pid, "status");
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r = get_proc_field(p, "CapEff", WHITESPACE, capeff);
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if (r == -ENOENT)
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return -ESRCH;
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return r;
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}
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static int get_process_link_contents(const char *proc_file, char **name) {
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int r;
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assert(proc_file);
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assert(name);
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r = readlink_malloc(proc_file, name);
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if (r == -ENOENT)
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return -ESRCH;
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if (r < 0)
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return r;
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return 0;
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}
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int get_process_exe(pid_t pid, char **name) {
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const char *p;
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char *d;
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int r;
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assert(pid >= 0);
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p = procfs_file_alloca(pid, "exe");
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r = get_process_link_contents(p, name);
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if (r < 0)
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return r;
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d = endswith(*name, " (deleted)");
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if (d)
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*d = '\0';
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return 0;
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}
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static int get_process_id(pid_t pid, const char *field, uid_t *uid) {
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_cleanup_fclose_ FILE *f = NULL;
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char line[LINE_MAX];
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const char *p;
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assert(field);
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assert(uid);
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if (pid < 0)
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return -EINVAL;
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p = procfs_file_alloca(pid, "status");
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f = fopen(p, "re");
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if (!f) {
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if (errno == ENOENT)
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return -ESRCH;
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return -errno;
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}
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FOREACH_LINE(line, f, return -errno) {
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char *l;
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l = strstrip(line);
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if (startswith(l, field)) {
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l += strlen(field);
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l += strspn(l, WHITESPACE);
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l[strcspn(l, WHITESPACE)] = 0;
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return parse_uid(l, uid);
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}
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}
|
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|
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return -EIO;
|
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}
|
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|
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int get_process_uid(pid_t pid, uid_t *uid) {
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|
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if (pid == 0 || pid == getpid_cached()) {
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*uid = getuid();
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return 0;
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}
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|
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return get_process_id(pid, "Uid:", uid);
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}
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int get_process_gid(pid_t pid, gid_t *gid) {
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if (pid == 0 || pid == getpid_cached()) {
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*gid = getgid();
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return 0;
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}
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|
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assert_cc(sizeof(uid_t) == sizeof(gid_t));
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return get_process_id(pid, "Gid:", gid);
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}
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int get_process_cwd(pid_t pid, char **cwd) {
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const char *p;
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|
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assert(pid >= 0);
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p = procfs_file_alloca(pid, "cwd");
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return get_process_link_contents(p, cwd);
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}
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|
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int get_process_root(pid_t pid, char **root) {
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const char *p;
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|
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assert(pid >= 0);
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p = procfs_file_alloca(pid, "root");
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return get_process_link_contents(p, root);
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}
|
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|
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int get_process_environ(pid_t pid, char **env) {
|
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_cleanup_fclose_ FILE *f = NULL;
|
|
_cleanup_free_ char *outcome = NULL;
|
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int c;
|
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const char *p;
|
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size_t allocated = 0, sz = 0;
|
|
|
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assert(pid >= 0);
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assert(env);
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|
|
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p = procfs_file_alloca(pid, "environ");
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|
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f = fopen(p, "re");
|
|
if (!f) {
|
|
if (errno == ENOENT)
|
|
return -ESRCH;
|
|
return -errno;
|
|
}
|
|
|
|
while ((c = fgetc(f)) != EOF) {
|
|
if (!GREEDY_REALLOC(outcome, allocated, sz + 5))
|
|
return -ENOMEM;
|
|
|
|
if (c == '\0')
|
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outcome[sz++] = '\n';
|
|
else
|
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sz += cescape_char(c, outcome + sz);
|
|
}
|
|
|
|
if (!outcome) {
|
|
outcome = strdup("");
|
|
if (!outcome)
|
|
return -ENOMEM;
|
|
} else
|
|
outcome[sz] = '\0';
|
|
|
|
*env = outcome;
|
|
outcome = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int get_process_ppid(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 || pid == getpid_cached()) {
|
|
*_ppid = getppid();
|
|
return 0;
|
|
}
|
|
|
|
p = procfs_file_alloca(pid, "stat");
|
|
r = read_one_line_file(p, &line);
|
|
if (r == -ENOENT)
|
|
return -ESRCH;
|
|
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 negative_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;
|
|
}
|
|
|
|
void sigkill_wait(pid_t pid) {
|
|
assert(pid > 1);
|
|
|
|
if (kill(pid, SIGKILL) > 0)
|
|
(void) wait_for_terminate(pid, NULL);
|
|
}
|
|
|
|
void sigkill_waitp(pid_t *pid) {
|
|
if (!pid)
|
|
return;
|
|
if (*pid <= 1)
|
|
return;
|
|
|
|
sigkill_wait(*pid);
|
|
}
|
|
|
|
int kill_and_sigcont(pid_t pid, int sig) {
|
|
int r;
|
|
|
|
r = kill(pid, sig) < 0 ? -errno : 0;
|
|
|
|
/* If this worked, also send SIGCONT, unless we already just sent a SIGCONT, or SIGKILL was sent which isn't
|
|
* affected by a process being suspended anyway. */
|
|
if (r >= 0 && !IN_SET(sig, SIGCONT, SIGKILL))
|
|
(void) 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) {
|
|
if (errno == ENOENT)
|
|
return -ESRCH;
|
|
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 (strneq(line, field, l) && 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 (pid <= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
|
|
return true;
|
|
|
|
if (pid == getpid_cached())
|
|
return true;
|
|
|
|
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;
|
|
|
|
if (pid <= 1) /* If we or PID 1 would be a zombie, this code would not be running */
|
|
return true;
|
|
|
|
if (pid == getpid_cached())
|
|
return true;
|
|
|
|
r = get_process_state(pid);
|
|
if (r == -ESRCH || r == 'Z')
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
int pid_from_same_root_fs(pid_t pid) {
|
|
const char *root;
|
|
|
|
if (pid < 0)
|
|
return false;
|
|
|
|
if (pid == 0 || pid == getpid_cached())
|
|
return true;
|
|
|
|
root = procfs_file_alloca(pid, "root");
|
|
|
|
return files_same(root, "/proc/1/root", 0);
|
|
}
|
|
|
|
bool is_main_thread(void) {
|
|
static thread_local int cached = 0;
|
|
|
|
if (_unlikely_(cached == 0))
|
|
cached = getpid_cached() == gettid() ? 1 : -1;
|
|
|
|
return cached > 0;
|
|
}
|
|
|
|
noreturn void freeze(void) {
|
|
|
|
log_close();
|
|
|
|
/* Make sure nobody waits for us on a socket anymore */
|
|
close_all_fds(NULL, 0);
|
|
|
|
sync();
|
|
|
|
for (;;)
|
|
pause();
|
|
}
|
|
|
|
bool oom_score_adjust_is_valid(int oa) {
|
|
return oa >= OOM_SCORE_ADJ_MIN && oa <= OOM_SCORE_ADJ_MAX;
|
|
}
|
|
|
|
unsigned long personality_from_string(const char *p) {
|
|
int architecture;
|
|
|
|
if (!p)
|
|
return PERSONALITY_INVALID;
|
|
|
|
/* Parse a personality specifier. We use our own identifiers that indicate specific ABIs, rather than just
|
|
* hints regarding the register size, since we want to keep things open for multiple locally supported ABIs for
|
|
* the same register size. */
|
|
|
|
architecture = architecture_from_string(p);
|
|
if (architecture < 0)
|
|
return PERSONALITY_INVALID;
|
|
|
|
if (architecture == native_architecture())
|
|
return PER_LINUX;
|
|
#ifdef SECONDARY_ARCHITECTURE
|
|
if (architecture == SECONDARY_ARCHITECTURE)
|
|
return PER_LINUX32;
|
|
#endif
|
|
|
|
return PERSONALITY_INVALID;
|
|
}
|
|
|
|
const char* personality_to_string(unsigned long p) {
|
|
int architecture = _ARCHITECTURE_INVALID;
|
|
|
|
if (p == PER_LINUX)
|
|
architecture = native_architecture();
|
|
#ifdef SECONDARY_ARCHITECTURE
|
|
else if (p == PER_LINUX32)
|
|
architecture = SECONDARY_ARCHITECTURE;
|
|
#endif
|
|
|
|
if (architecture < 0)
|
|
return NULL;
|
|
|
|
return architecture_to_string(architecture);
|
|
}
|
|
|
|
void valgrind_summary_hack(void) {
|
|
#ifdef HAVE_VALGRIND_VALGRIND_H
|
|
if (getpid_cached() == 1 && RUNNING_ON_VALGRIND) {
|
|
pid_t pid;
|
|
pid = raw_clone(SIGCHLD);
|
|
if (pid < 0)
|
|
log_emergency_errno(errno, "Failed to fork off valgrind helper: %m");
|
|
else if (pid == 0)
|
|
exit(EXIT_SUCCESS);
|
|
else {
|
|
log_info("Spawned valgrind helper as PID "PID_FMT".", pid);
|
|
(void) wait_for_terminate(pid, NULL);
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
int pid_compare_func(const void *a, const void *b) {
|
|
const pid_t *p = a, *q = b;
|
|
|
|
/* Suitable for usage in qsort() */
|
|
|
|
if (*p < *q)
|
|
return -1;
|
|
if (*p > *q)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
int ioprio_parse_priority(const char *s, int *ret) {
|
|
int i, r;
|
|
|
|
assert(s);
|
|
assert(ret);
|
|
|
|
r = safe_atoi(s, &i);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
if (!ioprio_priority_is_valid(i))
|
|
return -EINVAL;
|
|
|
|
*ret = i;
|
|
return 0;
|
|
}
|
|
|
|
/* The cached PID, possible values:
|
|
*
|
|
* == UNSET [0] → cache not initialized yet
|
|
* == BUSY [-1] → some thread is initializing it at the moment
|
|
* any other → the cached PID
|
|
*/
|
|
|
|
#define CACHED_PID_UNSET ((pid_t) 0)
|
|
#define CACHED_PID_BUSY ((pid_t) -1)
|
|
|
|
static pid_t cached_pid = CACHED_PID_UNSET;
|
|
|
|
static void reset_cached_pid(void) {
|
|
/* Invoked in the child after a fork(), i.e. at the first moment the PID changed */
|
|
cached_pid = CACHED_PID_UNSET;
|
|
}
|
|
|
|
/* We use glibc __register_atfork() + __dso_handle directly here, as they are not included in the glibc
|
|
* headers. __register_atfork() is mostly equivalent to pthread_atfork(), but doesn't require us to link against
|
|
* libpthread, as it is part of glibc anyway. */
|
|
extern int __register_atfork(void (*prepare) (void), void (*parent) (void), void (*child) (void), void * __dso_handle);
|
|
extern void* __dso_handle __attribute__ ((__weak__));
|
|
|
|
pid_t getpid_cached(void) {
|
|
pid_t current_value;
|
|
|
|
/* getpid_cached() is much like getpid(), but caches the value in local memory, to avoid having to invoke a
|
|
* system call each time. This restores glibc behaviour from before 2.24, when getpid() was unconditionally
|
|
* cached. Starting with 2.24 getpid() started to become prohibitively expensive when used for detecting when
|
|
* objects were used across fork()s. With this caching the old behaviour is somewhat restored.
|
|
*
|
|
* https://bugzilla.redhat.com/show_bug.cgi?id=1443976
|
|
* https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1d2bc2eae969543b89850e35e532f3144122d80a
|
|
*/
|
|
|
|
current_value = __sync_val_compare_and_swap(&cached_pid, CACHED_PID_UNSET, CACHED_PID_BUSY);
|
|
|
|
switch (current_value) {
|
|
|
|
case CACHED_PID_UNSET: { /* Not initialized yet, then do so now */
|
|
pid_t new_pid;
|
|
|
|
new_pid = getpid();
|
|
|
|
if (__register_atfork(NULL, NULL, reset_cached_pid, __dso_handle) != 0) {
|
|
/* OOM? Let's try again later */
|
|
cached_pid = CACHED_PID_UNSET;
|
|
return new_pid;
|
|
}
|
|
|
|
cached_pid = new_pid;
|
|
return new_pid;
|
|
}
|
|
|
|
case CACHED_PID_BUSY: /* Somebody else is currently initializing */
|
|
return getpid();
|
|
|
|
default: /* Properly initialized */
|
|
return current_value;
|
|
}
|
|
}
|
|
|
|
static const char *const ioprio_class_table[] = {
|
|
[IOPRIO_CLASS_NONE] = "none",
|
|
[IOPRIO_CLASS_RT] = "realtime",
|
|
[IOPRIO_CLASS_BE] = "best-effort",
|
|
[IOPRIO_CLASS_IDLE] = "idle"
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ioprio_class, int, INT_MAX);
|
|
|
|
static const char *const sigchld_code_table[] = {
|
|
[CLD_EXITED] = "exited",
|
|
[CLD_KILLED] = "killed",
|
|
[CLD_DUMPED] = "dumped",
|
|
[CLD_TRAPPED] = "trapped",
|
|
[CLD_STOPPED] = "stopped",
|
|
[CLD_CONTINUED] = "continued",
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP(sigchld_code, int);
|
|
|
|
static const char* const sched_policy_table[] = {
|
|
[SCHED_OTHER] = "other",
|
|
[SCHED_BATCH] = "batch",
|
|
[SCHED_IDLE] = "idle",
|
|
[SCHED_FIFO] = "fifo",
|
|
[SCHED_RR] = "rr"
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(sched_policy, int, INT_MAX);
|