src/basic/process-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <errno.h>
   5 #include <sched.h>
   6 #include <signal.h>
   7 #include <stdbool.h>
   8 #include <stddef.h>
   9 #include <stdio.h>
  10 #include <string.h>
  11 #include <sys/resource.h>
  12 #include <sys/types.h>
  13
  14 #include "alloc-util.h"
  15 #include "format-util.h"
  16 #include "macro.h"
  17 #include "namespace-util.h"
  18 #include "time-util.h"
  19
  20 #define procfs_file_alloca(pid, field)                                  \
  21         ({                                                              \
  22                 pid_t _pid_ = (pid);                                    \
  23                 const char *_field_ = (field);                          \
  24                 char *_r_;                                              \
  25                 if (_pid_ == 0) {                                       \
  26                         _r_ = newa(char, STRLEN("/proc/self/") + strlen(_field_) + 1); \
  27                         strcpy(stpcpy(_r_, "/proc/self/"), _field_);    \
  28                 } else {                                                \
  29                         _r_ = newa(char, STRLEN("/proc/") + DECIMAL_STR_MAX(pid_t) + 1 + strlen(_field_) + 1); \
  30                         sprintf(_r_, "/proc/" PID_FMT "/%s", _pid_, _field_); \
  31                 }                                                       \
  32                 (const char*) _r_;                                      \
  33         })
  34
  35 typedef enum ProcessCmdlineFlags {
  36         PROCESS_CMDLINE_COMM_FALLBACK = 1 << 0,
  37         PROCESS_CMDLINE_USE_LOCALE    = 1 << 1,
  38         PROCESS_CMDLINE_QUOTE         = 1 << 2,
  39         PROCESS_CMDLINE_QUOTE_POSIX   = 1 << 3,
  40 } ProcessCmdlineFlags;
  41
  42 int pid_get_comm(pid_t pid, char **ret);
  43 int pidref_get_comm(const PidRef *pid, char **ret);
  44 int pid_get_cmdline(pid_t pid, size_t max_columns, ProcessCmdlineFlags flags, char **ret);
  45 int pidref_get_cmdline(const PidRef *pid, size_t max_columns, ProcessCmdlineFlags flags, char **ret);
  46 int pid_get_cmdline_strv(pid_t pid, ProcessCmdlineFlags flags, char ***ret);
  47 int pidref_get_cmdline_strv(const PidRef *pid, ProcessCmdlineFlags flags, char ***ret);
  48 int get_process_exe(pid_t pid, char **ret);
  49 int pid_get_uid(pid_t pid, uid_t *ret);
  50 int pidref_get_uid(const PidRef *pid, uid_t *ret);
  51 int get_process_gid(pid_t pid, gid_t *ret);
  52 int get_process_capeff(pid_t pid, char **ret);
  53 int get_process_cwd(pid_t pid, char **ret);
  54 int get_process_root(pid_t pid, char **ret);
  55 int get_process_environ(pid_t pid, char **ret);
  56 int get_process_ppid(pid_t pid, pid_t *ret);
  57 int pid_get_start_time(pid_t pid, uint64_t *ret);
  58 int pidref_get_start_time(const PidRef* pid, uint64_t *ret);
  59 int get_process_umask(pid_t pid, mode_t *ret);
  60
  61 int container_get_leader(const char *machine, pid_t *pid);
  62
  63 int namespace_get_leader(pid_t pid, NamespaceType type, pid_t *ret);
  64
  65 int wait_for_terminate(pid_t pid, siginfo_t *status);
  66
  67 typedef enum WaitFlags {
  68         WAIT_LOG_ABNORMAL             = 1 << 0,
  69         WAIT_LOG_NON_ZERO_EXIT_STATUS = 1 << 1,
  70
  71         /* A shortcut for requesting the most complete logging */
  72         WAIT_LOG = WAIT_LOG_ABNORMAL|WAIT_LOG_NON_ZERO_EXIT_STATUS,
  73 } WaitFlags;
  74
  75 int wait_for_terminate_and_check(const char *name, pid_t pid, WaitFlags flags);
  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(const PidRef *pidref);
  95 int pid_is_my_child(pid_t pid);
  96 int pidref_is_my_child(const PidRef *pidref);
  97 int pid_from_same_root_fs(pid_t pid);
  98
  99 bool is_main_thread(void);
 100
 101 bool oom_score_adjust_is_valid(int oa);
 102
 103 #ifndef PERSONALITY_INVALID
 104 /* personality(7) 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 0xffffffffLU
 108 #endif
 109
 110 unsigned long personality_from_string(const char *p);
 111 const char *personality_to_string(unsigned long);
 112
 113 int safe_personality(unsigned long p);
 114 int opinionated_personality(unsigned long *ret);
 115
 116 const char *sigchld_code_to_string(int i) _const_;
 117 int sigchld_code_from_string(const char *s) _pure_;
 118
 119 int sched_policy_to_string_alloc(int i, char **s);
 120 int sched_policy_from_string(const char *s);
 121
 122 static inline pid_t PTR_TO_PID(const void *p) {
 123         return (pid_t) ((uintptr_t) p);
 124 }
 125
 126 static inline void* PID_TO_PTR(pid_t pid) {
 127         return (void*) ((uintptr_t) pid);
 128 }
 129
 130 void valgrind_summary_hack(void);
 131
 132 int pid_compare_func(const pid_t *a, const pid_t *b);
 133
 134 static inline bool nice_is_valid(int n) {
 135         return n >= PRIO_MIN && n < PRIO_MAX;
 136 }
 137
 138 static inline bool sched_policy_is_valid(int i) {
 139         return IN_SET(i, SCHED_OTHER, SCHED_BATCH, SCHED_IDLE, SCHED_FIFO, SCHED_RR);
 140 }
 141
 142 static inline bool sched_priority_is_valid(int i) {
 143         return i >= 0 && i <= sched_get_priority_max(SCHED_RR);
 144 }
 145
 146 static inline bool pid_is_valid(pid_t p) {
 147         return p > 0;
 148 }
 149
 150 pid_t getpid_cached(void);
 151 void reset_cached_pid(void);
 152
 153 int must_be_root(void);
 154
 155 pid_t clone_with_nested_stack(int (*fn)(void *), int flags, void *userdata);
 156
 157 /* 💣 Note that FORK_NEW_USERNS, FORK_NEW_MOUNTNS, or FORK_NEW_NETNS should not be called in threaded
 158  * programs, because they cause us to use raw_clone() which does not synchronize the glibc malloc() locks,
 159  * and thus will cause deadlocks if the parent uses threads and the child does memory allocations. Hence: if
 160  * the parent is threaded these flags may not be used. These flags cannot be used if the parent uses threads
 161  * or the child uses malloc(). 💣 */
 162 typedef enum ForkFlags {
 163         FORK_RESET_SIGNALS      = 1 <<  0, /* Reset all signal handlers and signal mask */
 164         FORK_CLOSE_ALL_FDS      = 1 <<  1, /* Close all open file descriptors in the child, except for 0,1,2 */
 165         FORK_DEATHSIG_SIGTERM   = 1 <<  2, /* Set PR_DEATHSIG in the child to SIGTERM */
 166         FORK_DEATHSIG_SIGINT    = 1 <<  3, /* Set PR_DEATHSIG in the child to SIGINT */
 167         FORK_DEATHSIG_SIGKILL   = 1 <<  4, /* Set PR_DEATHSIG in the child to SIGKILL */
 168         FORK_REARRANGE_STDIO    = 1 <<  5, /* Connect 0,1,2 to specified fds or /dev/null */
 169         FORK_REOPEN_LOG         = 1 <<  6, /* Reopen log connection */
 170         FORK_LOG                = 1 <<  7, /* Log above LOG_DEBUG log level about failures */
 171         FORK_WAIT               = 1 <<  8, /* Wait until child exited */
 172         FORK_NEW_MOUNTNS        = 1 <<  9, /* Run child in its own mount namespace                               💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 173         FORK_MOUNTNS_SLAVE      = 1 << 10, /* Make child's mount namespace MS_SLAVE */
 174         FORK_PRIVATE_TMP        = 1 << 11, /* Mount new /tmp/ in the child (combine with FORK_NEW_MOUNTNS!) */
 175         FORK_RLIMIT_NOFILE_SAFE = 1 << 12, /* Set RLIMIT_NOFILE soft limit to 1K for select() compat */
 176         FORK_STDOUT_TO_STDERR   = 1 << 13, /* Make stdout a copy of stderr */
 177         FORK_FLUSH_STDIO        = 1 << 14, /* fflush() stdout (and stderr) before forking */
 178         FORK_NEW_USERNS         = 1 << 15, /* Run child in its own user namespace                                💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 179         FORK_CLOEXEC_OFF        = 1 << 16, /* In the child: turn off O_CLOEXEC on all fds in except_fds[] */
 180         FORK_KEEP_NOTIFY_SOCKET = 1 << 17, /* Unless this specified, $NOTIFY_SOCKET will be unset. */
 181         FORK_DETACH             = 1 << 18, /* Double fork if needed to ensure PID1/subreaper is parent */
 182         FORK_NEW_NETNS          = 1 << 19, /* Run child in its own network namespace                             💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
 183 } ForkFlags;
 184
 185 int safe_fork_full(
 186                 const char *name,
 187                 const int stdio_fds[3],
 188                 const int except_fds[],
 189                 size_t n_except_fds,
 190                 ForkFlags flags,
 191                 pid_t *ret_pid);
 192
 193 static inline int safe_fork(const char *name, ForkFlags flags, pid_t *ret_pid) {
 194         return safe_fork_full(name, NULL, NULL, 0, flags, ret_pid);
 195 }
 196
 197 int pidref_safe_fork_full(
 198                 const char *name,
 199                 const int stdio_fds[3],
 200                 const int except_fds[],
 201                 size_t n_except_fds,
 202                 ForkFlags flags,
 203                 PidRef *ret_pid);
 204
 205 static inline int pidref_safe_fork(const char *name, ForkFlags flags, PidRef *ret_pid) {
 206         return pidref_safe_fork_full(name, NULL, NULL, 0, flags, ret_pid);
 207 }
 208
 209 int namespace_fork(const char *outer_name, const char *inner_name, const int except_fds[], size_t n_except_fds, ForkFlags flags, int pidns_fd, int mntns_fd, int netns_fd, int userns_fd, int root_fd, pid_t *ret_pid);
 210
 211 int set_oom_score_adjust(int value);
 212 int get_oom_score_adjust(int *ret);
 213
 214 /* The highest possibly (theoretic) pid_t value on this architecture. */
 215 #define PID_T_MAX ((pid_t) INT32_MAX)
 216 /* The maximum number of concurrent processes Linux allows on this architecture, as well as the highest valid PID value
 217  * the kernel will potentially assign. This reflects a value compiled into the kernel (PID_MAX_LIMIT), and sets the
 218  * upper boundary on what may be written to the /proc/sys/kernel/pid_max sysctl (but do note that the sysctl is off by
 219  * 1, since PID 0 can never exist and there can hence only be one process less than the limit would suggest). Since
 220  * these values are documented in proc(5) we feel quite confident that they are stable enough for the near future at
 221  * least to define them here too. */
 222 #define TASKS_MAX 4194303U
 223
 224 assert_cc(TASKS_MAX <= (unsigned long) PID_T_MAX);
 225
 226 /* Like TAKE_PTR() but for pid_t, resetting them to 0 */
 227 #define TAKE_PID(pid) TAKE_GENERIC(pid, pid_t, 0)
 228
 229 int pidfd_get_pid(int fd, pid_t *ret);
 230 int pidfd_verify_pid(int pidfd, pid_t pid);
 231
 232 int setpriority_closest(int priority);
 233
 234 _noreturn_ void freeze(void);
 235
 236 int get_process_threads(pid_t pid);
 237
 238 int is_reaper_process(void);
 239 int make_reaper_process(bool b);
 240
 241 int posix_spawn_wrapper(const char *path, char *const *argv, char *const *envp, PidRef *ret_pidref);
 242
 243 int proc_dir_open(DIR **ret);
 244 int proc_dir_read(DIR *d, pid_t *ret);
 245 int proc_dir_read_pidref(DIR *d, PidRef *ret);