src/basic/process-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   This file is part of systemd.
   6
   7   Copyright 2010 Lennart Poettering
   8 ***/
   9
  10 #include <alloca.h>
  11 #include <errno.h>
  12 #include <sched.h>
  13 #include <signal.h>
  14 #include <stdbool.h>
  15 #include <stddef.h>
  16 #include <stdio.h>
  17 #include <string.h>
  18 #include <sys/resource.h>
  19 #include <sys/types.h>
  20
  21 #include "format-util.h"
  22 #include "ioprio.h"
  23 #include "macro.h"
  24 #include "time-util.h"
  25
  26 #define procfs_file_alloca(pid, field)                                  \
  27         ({                                                              \
  28                 pid_t _pid_ = (pid);                                    \
  29                 const char *_r_;                                        \
  30                 if (_pid_ == 0) {                                       \
  31                         _r_ = ("/proc/self/" field);                    \
  32                 } else {                                                \
  33                         _r_ = alloca(STRLEN("/proc/") + DECIMAL_STR_MAX(pid_t) + 1 + sizeof(field)); \
  34                         sprintf((char*) _r_, "/proc/"PID_FMT"/" field, _pid_);                       \
  35                 }                                                       \
  36                 _r_;                                                    \
  37         })
  38
  39 int get_process_state(pid_t pid);
  40 int get_process_comm(pid_t pid, char **name);
  41 int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line);
  42 int get_process_exe(pid_t pid, char **name);
  43 int get_process_uid(pid_t pid, uid_t *uid);
  44 int get_process_gid(pid_t pid, gid_t *gid);
  45 int get_process_capeff(pid_t pid, char **capeff);
  46 int get_process_cwd(pid_t pid, char **cwd);
  47 int get_process_root(pid_t pid, char **root);
  48 int get_process_environ(pid_t pid, char **environ);
  49 int get_process_ppid(pid_t pid, pid_t *ppid);
  50
  51 int wait_for_terminate(pid_t pid, siginfo_t *status);
  52
  53 typedef enum WaitFlags {
  54         WAIT_LOG_ABNORMAL             = 1U << 0,
  55         WAIT_LOG_NON_ZERO_EXIT_STATUS = 1U << 1,
  56
  57         /* A shortcut for requesting the most complete logging */
  58         WAIT_LOG = WAIT_LOG_ABNORMAL|WAIT_LOG_NON_ZERO_EXIT_STATUS,
  59 } WaitFlags;
  60
  61 int wait_for_terminate_and_check(const char *name, pid_t pid, WaitFlags flags);
  62 int wait_for_terminate_with_timeout(pid_t pid, usec_t timeout);
  63
  64 void sigkill_wait(pid_t pid);
  65 void sigkill_waitp(pid_t *pid);
  66 void sigterm_wait(pid_t pid);
  67
  68 int kill_and_sigcont(pid_t pid, int sig);
  69
  70 int rename_process(const char name[]);
  71 int is_kernel_thread(pid_t pid);
  72
  73 int getenv_for_pid(pid_t pid, const char *field, char **_value);
  74
  75 bool pid_is_alive(pid_t pid);
  76 bool pid_is_unwaited(pid_t pid);
  77 int pid_from_same_root_fs(pid_t pid);
  78
  79 bool is_main_thread(void);
  80
  81 _noreturn_ void freeze(void);
  82
  83 bool oom_score_adjust_is_valid(int oa);
  84
  85 #ifndef PERSONALITY_INVALID
  86 /* personality(7) documents that 0xffffffffUL is used for querying the
  87  * current personality, hence let's use that here as error
  88  * indicator. */
  89 #define PERSONALITY_INVALID 0xffffffffLU
  90 #endif
  91
  92 unsigned long personality_from_string(const char *p);
  93 const char *personality_to_string(unsigned long);
  94
  95 int safe_personality(unsigned long p);
  96 int opinionated_personality(unsigned long *ret);
  97
  98 int ioprio_class_to_string_alloc(int i, char **s);
  99 int ioprio_class_from_string(const char *s);
 100
 101 const char *sigchld_code_to_string(int i) _const_;
 102 int sigchld_code_from_string(const char *s) _pure_;
 103
 104 int sched_policy_to_string_alloc(int i, char **s);
 105 int sched_policy_from_string(const char *s);
 106
 107 static inline pid_t PTR_TO_PID(const void *p) {
 108         return (pid_t) ((uintptr_t) p);
 109 }
 110
 111 static inline void* PID_TO_PTR(pid_t pid) {
 112         return (void*) ((uintptr_t) pid);
 113 }
 114
 115 void valgrind_summary_hack(void);
 116
 117 int pid_compare_func(const void *a, const void *b);
 118
 119 static inline bool nice_is_valid(int n) {
 120         return n >= PRIO_MIN && n < PRIO_MAX;
 121 }
 122
 123 static inline bool sched_policy_is_valid(int i) {
 124         return IN_SET(i, SCHED_OTHER, SCHED_BATCH, SCHED_IDLE, SCHED_FIFO, SCHED_RR);
 125 }
 126
 127 static inline bool sched_priority_is_valid(int i) {
 128         return i >= 0 && i <= sched_get_priority_max(SCHED_RR);
 129 }
 130
 131 static inline bool ioprio_class_is_valid(int i) {
 132         return IN_SET(i, IOPRIO_CLASS_NONE, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE);
 133 }
 134
 135 static inline bool ioprio_priority_is_valid(int i) {
 136         return i >= 0 && i < IOPRIO_BE_NR;
 137 }
 138
 139 static inline bool pid_is_valid(pid_t p) {
 140         return p > 0;
 141 }
 142
 143 static inline int sched_policy_to_string_alloc_with_check(int n, char **s) {
 144         if (!sched_policy_is_valid(n))
 145                 return -EINVAL;
 146
 147         return sched_policy_to_string_alloc(n, s);
 148 }
 149
 150 int ioprio_parse_priority(const char *s, int *ret);
 151
 152 pid_t getpid_cached(void);
 153 void reset_cached_pid(void);
 154
 155 int must_be_root(void);
 156
 157 typedef enum ForkFlags {
 158         FORK_RESET_SIGNALS = 1U << 0,
 159         FORK_CLOSE_ALL_FDS = 1U << 1,
 160         FORK_DEATHSIG      = 1U << 2,
 161         FORK_NULL_STDIO    = 1U << 3,
 162         FORK_REOPEN_LOG    = 1U << 4,
 163         FORK_LOG           = 1U << 5,
 164         FORK_WAIT          = 1U << 6,
 165         FORK_NEW_MOUNTNS   = 1U << 7,
 166 } ForkFlags;
 167
 168 int safe_fork_full(const char *name, const int except_fds[], size_t n_except_fds, ForkFlags flags, pid_t *ret_pid);
 169
 170 static inline int safe_fork(const char *name, ForkFlags flags, pid_t *ret_pid) {
 171         return safe_fork_full(name, NULL, 0, flags, ret_pid);
 172 }
 173
 174 int fork_agent(const char *name, const int except[], size_t n_except, pid_t *pid, const char *path, ...);
 175
 176 #if SIZEOF_PID_T == 4
 177 /* The highest possibly (theoretic) pid_t value on this architecture. */
 178 #define PID_T_MAX ((pid_t) INT32_MAX)
 179 /* The maximum number of concurrent processes Linux allows on this architecture, as well as the highest valid PID value
 180  * the kernel will potentially assign. This reflects a value compiled into the kernel (PID_MAX_LIMIT), and sets the
 181  * upper boundary on what may be written to the /proc/sys/kernel/pid_max sysctl (but do note that the sysctl is off by
 182  * 1, since PID 0 can never exist and there can hence only be one process less than the limit would suggest). Since
 183  * these values are documented in proc(5) we feel quite confident that they are stable enough for the near future at
 184  * least to define them here too. */
 185 #define TASKS_MAX 4194303U
 186 #elif SIZEOF_PID_T == 2
 187 #define PID_T_MAX ((pid_t) INT16_MAX)
 188 #define TASKS_MAX 32767U
 189 #else
 190 #error "Unknown pid_t size"
 191 #endif
 192
 193 assert_cc(TASKS_MAX <= (unsigned long) PID_T_MAX)
 194
 195 /* Like TAKE_PTR() but for child PIDs, resetting them to 0 */
 196 #define TAKE_PID(pid)                           \
 197         ({                                      \
 198                 pid_t _pid_ = (pid);            \
 199                 (pid) = 0;                      \
 200                 _pid_;                          \
 201         })