src/basic/process-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <signal.h>
   5
   6 #include "fileio.h"
   7 #include "format-util.h"
   8 #include "forward.h"
   9 #include "string-util.h"
  10
  11 #define procfs_file_alloca(pid, field)                                  \
  12         ({                                                              \
  13                 pid_t _pid_ = (pid);                                    \
  14                 const char *_field_ = (field);                          \
  15                 char *_r_;                                              \
  16                 if (_pid_ == 0)                                         \
  17                         _r_ = strjoina("/proc/self/", _field_);         \
  18                 else {                                                  \
  19                         assert(_pid_ > 0);                              \
  20                         _r_ = newa(char, STRLEN("/proc/") + DECIMAL_STR_MAX(pid_t) + 1 + strlen(_field_) + 1); \
  21                         sprintf(_r_, "/proc/" PID_FMT "/%s", _pid_, _field_); \
  22                 }                                                       \
  23                 (const char*) _r_;                                      \
  24         })
  25
  26 static inline int procfs_file_get_field(pid_t pid, const char *name, const char *key, char **ret) {
  27         return get_proc_field(procfs_file_alloca(pid, name), key, ret);
  28 }
  29
  30 typedef enum ProcessCmdlineFlags {
  31         PROCESS_CMDLINE_COMM_FALLBACK = 1 << 0,
  32         PROCESS_CMDLINE_USE_LOCALE    = 1 << 1,
  33         PROCESS_CMDLINE_QUOTE         = 1 << 2,
  34         PROCESS_CMDLINE_QUOTE_POSIX   = 1 << 3,
  35 } ProcessCmdlineFlags;
  36
  37 int pid_get_comm(pid_t pid, char **ret);
  38 int pidref_get_comm(const PidRef *pid, char **ret);
  39 int pid_get_cmdline(pid_t pid, size_t max_columns, ProcessCmdlineFlags flags, char **ret);
  40 int pidref_get_cmdline(const PidRef *pid, size_t max_columns, ProcessCmdlineFlags flags, char **ret);
  41 int pid_get_cmdline_strv(pid_t pid, ProcessCmdlineFlags flags, char ***ret);
  42 int pidref_get_cmdline_strv(const PidRef *pid, ProcessCmdlineFlags flags, char ***ret);
  43 int get_process_exe(pid_t pid, char **ret);
  44 int pid_get_uid(pid_t pid, uid_t *ret);
  45 int pidref_get_uid(const PidRef *pid, uid_t *ret);
  46 int get_process_gid(pid_t pid, gid_t *ret);
  47 int get_process_cwd(pid_t pid, char **ret);
  48 int get_process_root(pid_t pid, char **ret);
  49 int get_process_environ(pid_t pid, char **ret);
  50 int pid_get_ppid(pid_t pid, pid_t *ret);
  51 int pidref_get_ppid(const PidRef *pidref, pid_t *ret);
  52 int pidref_get_ppid_as_pidref(const PidRef *pidref, PidRef *ret);
  53 int pid_get_start_time(pid_t pid, usec_t *ret);
  54 int pidref_get_start_time(const PidRef *pid, usec_t *ret);
  55 int get_process_umask(pid_t pid, mode_t *ret);
  56
  57 int container_get_leader(const char *machine, pid_t *pid);
  58
  59 static inline bool SIGINFO_CODE_IS_DEAD(int code) {
  60         return IN_SET(code, CLD_EXITED, CLD_KILLED, CLD_DUMPED);
  61 }
  62
  63 int wait_for_terminate(pid_t pid, siginfo_t *ret);
  64
  65 typedef enum WaitFlags {
  66         WAIT_LOG_ABNORMAL             = 1 << 0,
  67         WAIT_LOG_NON_ZERO_EXIT_STATUS = 1 << 1,
  68
  69         /* A shortcut for requesting the most complete logging */
  70         WAIT_LOG = WAIT_LOG_ABNORMAL|WAIT_LOG_NON_ZERO_EXIT_STATUS,
  71 } WaitFlags;
  72
  73 int pidref_wait_for_terminate_and_check(const char *name, PidRef *pidref, WaitFlags flags);
  74 int wait_for_terminate_and_check(const char *name, pid_t pid, WaitFlags flags);
  75
  76 int wait_for_terminate_with_timeout(pid_t pid, usec_t timeout);
  77
  78 void sigkill_wait(pid_t pid);
  79 void sigkill_waitp(pid_t *pid);
  80 void sigterm_wait(pid_t pid);
  81 void sigkill_nowait(pid_t pid);
  82 void sigkill_nowaitp(pid_t *pid);
  83
  84 int kill_and_sigcont(pid_t pid, int sig);
  85
  86 int pid_is_kernel_thread(pid_t pid);
  87 int pidref_is_kernel_thread(const PidRef *pid);
  88
  89 int getenv_for_pid(pid_t pid, const char *field, char **_value);
  90
  91 int pid_is_alive(pid_t pid);
  92 int pidref_is_alive(const PidRef *pidref);
  93 int pid_is_unwaited(pid_t pid);
  94 int pidref_is_unwaited(PidRef *pidref);
  95 int pid_is_my_child(pid_t pid);
  96 int pidref_is_my_child(PidRef *pidref);
  97 int pidref_from_same_root_fs(PidRef *a, PidRef *b);
  98
  99 bool is_main_thread(void);
 100
 101 bool oom_score_adjust_is_valid(int oa);
 102
 103 #ifndef PERSONALITY_INVALID
 104 /* personality(2) documents that 0xFFFFFFFFUL is used for querying the
 105  * current personality, hence let's use that here as error
 106  * indicator. */
 107 #define PERSONALITY_INVALID 0xFFFFFFFFUL
 108 #endif
 109
 110 /* The personality() syscall returns a 32-bit value where the top three bytes are reserved for flags that
 111  * emulate historical or architectural quirks, and only the least significant byte reflects the actual
 112  * personality we're interested in. */
 113 #define OPINIONATED_PERSONALITY_MASK 0xFFUL
 114
 115 unsigned long personality_from_string(const char *p);
 116 const char* personality_to_string(unsigned long);
 117
 118 int safe_personality(unsigned long p);
 119 int opinionated_personality(unsigned long *ret);
 120
 121 const char* sigchld_code_to_string(int i) _const_;
 122 int sigchld_code_from_string(const char *s) _pure_;
 123
 124 int sched_policy_to_string_alloc(int i, char **s);
 125 int sched_policy_from_string(const char *s);
 126
 127 static inline pid_t PTR_TO_PID(const void *p) {
 128         return (pid_t) ((uintptr_t) p);
 129 }
 130
 131 static inline void* PID_TO_PTR(pid_t pid) {
 132         return (void*) ((uintptr_t) pid);
 133 }
 134
 135 void valgrind_summary_hack(void);
 136
 137 int pid_compare_func(const pid_t *a, const pid_t *b);
 138
 139 bool nice_is_valid(int n) _const_;
 140
 141 bool sched_policy_is_valid(int i) _const_;
 142 bool sched_priority_is_valid(int i) _const_;
 143
 144 #define PID_AUTOMATIC ((pid_t) INT_MIN) /* special value indicating "acquire pid from connection peer" */
 145
 146 static inline bool pid_is_valid(pid_t p) {
 147         return p > 0;
 148 }
 149
 150 static inline bool pid_is_automatic(pid_t p) {
 151         return p == PID_AUTOMATIC;
 152 }
 153
 154 pid_t getpid_cached(void);
 155 void reset_cached_pid(void);
 156
 157 int must_be_root(void);
 158
 159 pid_t clone_with_nested_stack(int (*fn)(void *), int flags, void *userdata);
 160
 161 /* 💣 Note that FORK_NEW_USERNS, FORK_NEW_MOUNTNS, FORK_NEW_NETNS or FORK_NEW_PIDNS should not be called in threaded
 162  * programs, because they cause us to use raw_clone() which does not synchronize the glibc malloc() locks,
 163  * and thus will cause deadlocks if the parent uses threads and the child does memory allocations. Hence: if
 164  * the parent is threaded these flags may not be used. These flags cannot be used if the parent uses threads
 165  * or the child uses malloc(). 💣 */
 166 typedef enum ForkFlags {
 167         FORK_RESET_SIGNALS      = 1 <<  0, /* Reset all signal handlers and signal mask */
 168         FORK_CLOSE_ALL_FDS      = 1 <<  1, /* Close all open file descriptors in the child, except for 0,1,2 */
 169         FORK_DEATHSIG_SIGTERM   = 1 <<  2, /* Set PR_DEATHSIG in the child to SIGTERM */
 170         FORK_DEATHSIG_SIGINT    = 1 <<  3, /* Set PR_DEATHSIG in the child to SIGINT */
 171         FORK_DEATHSIG_SIGKILL   = 1 <<  4, /* Set PR_DEATHSIG in the child to SIGKILL */
 172         FORK_REARRANGE_STDIO    = 1 <<  5, /* Connect 0,1,2 to specified fds or /dev/null */
 173         FORK_REOPEN_LOG         = 1 <<  6, /* Reopen log connection */
 174         FORK_LOG                = 1 <<  7, /* Log above LOG_DEBUG log level about failures */
 175         FORK_WAIT               = 1 <<  8, /* Wait until child exited */
 176         FORK_MOUNTNS_SLAVE      = 1 <<  9, /* Make child's mount namespace MS_SLAVE */
 177         FORK_PRIVATE_TMP        = 1 << 10, /* Mount new /tmp/ in the child (combine with FORK_NEW_MOUNTNS!) */
 178         FORK_RLIMIT_NOFILE_SAFE = 1 << 11, /* Set RLIMIT_NOFILE soft limit to 1K for select() compat */
 179         FORK_STDOUT_TO_STDERR   = 1 << 12, /* Make stdout a copy of stderr */
 180         FORK_FLUSH_STDIO        = 1 << 13, /* fflush() stdout (and stderr) before forking */
 181         FORK_CLOEXEC_OFF        = 1 << 14, /* In the child: turn off O_CLOEXEC on all fds in except_fds[] */
 182         FORK_KEEP_NOTIFY_SOCKET = 1 << 15, /* Unless this specified, $NOTIFY_SOCKET will be unset. */
 183         FORK_DETACH             = 1 << 16, /* Double fork if needed to ensure PID1/subreaper is parent */
 184         FORK_PACK_FDS           = 1 << 17, /* Rearrange the passed FDs to be FD 3,4,5,etc. Updates the array in place (combine with FORK_CLOSE_ALL_FDS!) */
 185         FORK_NEW_MOUNTNS        = 1 << 18, /* Run child in its own mount namespace                               💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 186         FORK_NEW_USERNS         = 1 << 19, /* Run child in its own user namespace                                💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 187         FORK_NEW_NETNS          = 1 << 20, /* Run child in its own network namespace                             💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 188         FORK_NEW_PIDNS          = 1 << 21, /* Run child in its own PID namespace                                 💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 189         FORK_FREEZE             = 1 << 22, /* Don't return in child, just call freeze() instead */
 190         FORK_PID_ONLY           = 1 << 23, /* Don't open a pidfd referencing the child process */
 191 } ForkFlags;
 192
 193 int pidref_safe_fork_full(
 194                 const char *name,
 195                 const int stdio_fds[3],
 196                 int except_fds[],
 197                 size_t n_except_fds,
 198                 ForkFlags flags,
 199                 PidRef *ret_pid);
 200
 201 static inline int pidref_safe_fork(const char *name, ForkFlags flags, PidRef *ret_pid) {
 202         return pidref_safe_fork_full(name, NULL, NULL, 0, flags, ret_pid);
 203 }
 204
 205 int safe_fork_full(
 206                 const char *name,
 207                 const int stdio_fds[3],
 208                 int except_fds[],
 209                 size_t n_except_fds,
 210                 ForkFlags flags,
 211                 pid_t *ret_pid);
 212
 213 static inline int safe_fork(const char *name, ForkFlags flags, pid_t *ret_pid) {
 214         return safe_fork_full(name, NULL, NULL, 0, flags, ret_pid);
 215 }
 216
 217 int namespace_fork(
 218                 const char *outer_name,
 219                 const char *inner_name,
 220                 int except_fds[],
 221                 size_t n_except_fds,
 222                 ForkFlags flags,
 223                 int pidns_fd,
 224                 int mntns_fd,
 225                 int netns_fd,
 226                 int userns_fd,
 227                 int root_fd,
 228                 pid_t *ret_pid);
 229
 230 int set_oom_score_adjust(int value);
 231 int get_oom_score_adjust(int *ret);
 232
 233 /* The highest possibly (theoretic) pid_t value on this architecture. */
 234 #define PID_T_MAX ((pid_t) INT32_MAX)
 235 /* The maximum number of concurrent processes Linux allows on this architecture, as well as the highest valid PID value
 236  * the kernel will potentially assign. This reflects a value compiled into the kernel (PID_MAX_LIMIT), and sets the
 237  * upper boundary on what may be written to the /proc/sys/kernel/pid_max sysctl (but do note that the sysctl is off by
 238  * 1, since PID 0 can never exist and there can hence only be one process less than the limit would suggest). Since
 239  * these values are documented in proc(5) we feel quite confident that they are stable enough for the near future at
 240  * least to define them here too. */
 241 #define TASKS_MAX 4194303U
 242
 243 assert_cc(TASKS_MAX <= (unsigned long) PID_T_MAX);
 244
 245 /* Like TAKE_PTR() but for pid_t, resetting them to 0 */
 246 #define TAKE_PID(pid) TAKE_GENERIC(pid, pid_t, 0)
 247
 248 int setpriority_closest(int priority);
 249
 250 _noreturn_ void freeze(void);
 251
 252 int get_process_threads(pid_t pid);
 253
 254 int is_reaper_process(void);
 255 int make_reaper_process(bool b);
 256
 257 int posix_spawn_wrapper(
 258                 const char *path,
 259                 char * const *argv,
 260                 char * const *envp,
 261                 const char *cgroup,
 262                 PidRef *ret_pidref);
 263
 264 int proc_dir_open(DIR **ret);
 265 int proc_dir_read(DIR *d, pid_t *ret);
 266 int proc_dir_read_pidref(DIR *d, PidRef *ret);
 267
 268 _noreturn_ void report_errno_and_exit(int errno_fd, int error);
 269 int read_errno(int errno_fd);