Linux Manuals session 2

getrlimit, setrlimit, prlimit – get/set resource limits Synopsis#include <sys/time.h> #include <sys/resource.h> int getrlimit(int resource, struct rlimit *rlim); int setrlimit(int resource, const struct rlimit *rlim); int prlimit(pid_t pid, int resource, const struct rlimit *new_limit, struct rlimit *old_limit); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): prlimit(): _GNU_SOURCE DescriptionThe getrlimit() and setrlimit() system calls get and set…

setreuid, setregid – set real and/or effective user or group ID Synopsis#include <sys/types.h> #include <unistd.h> int setreuid(uid_t ruid, uid_t euid); int setregid(gid_t rgid, gid_t egid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): setreuid(), setregid(): _XOPEN_SOURCE >= 500     || /* Since glibc 2.19: */ _DEFAULT_SOURCE     || /* Glibc versions <= 2.19: */ _BSD_SOURCEDescriptionsetreuid() sets real and effective user IDs of the calling process. Supplying a value of…

setreuid, setregid – set real and/or effective user or group ID Synopsis#include <sys/types.h> #include <unistd.h> int setreuid(uid_t ruid, uid_t euid); int setregid(gid_t rgid, gid_t egid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): setreuid(), setregid(): _XOPEN_SOURCE >= 500     || /* Since glibc 2.19: */ _DEFAULT_SOURCE     || /* Glibc versions <= 2.19: */ _BSD_SOURCEDescriptionsetreuid() sets real and effective user IDs of the calling process. Supplying a value of…

setresuid, setresgid – set real, effective and saved user or group ID Synopsis#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> int setresuid(uid_t ruid, uid_t euid, uid_t suid); int setresgid(gid_t rgid, gid_t egid, gid_t sgid); Descriptionsetresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the calling process. An unprivileged process…

setresuid, setresgid – set real, effective and saved user or group ID Synopsis#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> int setresuid(uid_t ruid, uid_t euid, uid_t suid); int setresgid(gid_t rgid, gid_t egid, gid_t sgid); Descriptionsetresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the calling process. An unprivileged process…

setresuid, setresgid – set real, effective and saved user or group ID Synopsis#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> int setresuid(uid_t ruid, uid_t euid, uid_t suid); int setresgid(gid_t rgid, gid_t egid, gid_t sgid); Descriptionsetresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the calling process. An unprivileged process…

setresuid, setresgid – set real, effective and saved user or group ID Synopsis#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> int setresuid(uid_t ruid, uid_t euid, uid_t suid); int setresgid(gid_t rgid, gid_t egid, gid_t sgid); Descriptionsetresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the calling process. An unprivileged process…

setreuid, setregid – set real and/or effective user or group ID Synopsis#include <sys/types.h> #include <unistd.h> int setreuid(uid_t ruid, uid_t euid); int setregid(gid_t rgid, gid_t egid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): setreuid(), setregid(): _XOPEN_SOURCE >= 500     || /* Since glibc 2.19: */ _DEFAULT_SOURCE     || /* Glibc versions <= 2.19: */ _BSD_SOURCEDescriptionsetreuid() sets real and effective user IDs of the calling process. Supplying a value of…

setreuid, setregid – set real and/or effective user or group ID Synopsis#include <sys/types.h> #include <unistd.h> int setreuid(uid_t ruid, uid_t euid); int setregid(gid_t rgid, gid_t egid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): setreuid(), setregid(): _XOPEN_SOURCE >= 500     || /* Since glibc 2.19: */ _DEFAULT_SOURCE     || /* Glibc versions <= 2.19: */ _BSD_SOURCEDescriptionsetreuid() sets real and effective user IDs of the calling process. Supplying a value of…

getpriority, setpriority – get/set program scheduling priority Synopsis#include <sys/time.h> #include <sys/resource.h> int getpriority(int which, id_t who); int setpriority(int which, id_t who, int prio); DescriptionThe scheduling priority of the process, process group, or user, as indicated by which and who is obtained with the getpriority() call and set with the setpriority() call. The process attribute dealt…

setpgid, getpgid, setpgrp, getpgrp – set/get process group Synopsis#include <sys/types.h> #include <unistd.h> int setpgid(pid_t pid, pid_t pgid); pid_t getpgid(pid_t pid); pid_t getpgrp(void); /* POSIX.1 version */ pid_t getpgrp(pid_t pid); /* BSD version */ int setpgrp(void); /* System V version */ int setpgrp(pid_t pid, pid_t pgid); /* BSD version */ Feature Test Macro Requirements for glibc…

setpgid, getpgid, setpgrp, getpgrp – set/get process group Synopsis#include <sys/types.h> #include <unistd.h> int setpgid(pid_t pid, pid_t pgid); pid_t getpgid(pid_t pid); pid_t getpgrp(void); /* POSIX.1 version */ pid_t getpgrp(pid_t pid); /* BSD version */ int setpgrp(void); /* System V version */ int setpgrp(pid_t pid, pid_t pgid); /* BSD version */ Feature Test Macro Requirements for glibc…

setns – reassociate thread with a namespace Synopsis#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <sched.h> int setns(int fd, int nstype);DescriptionThe setns() system call allows the calling thread to move into different namespaces. The fd argument is one of the following: • a file descriptor referring to one of the magic links in a /proc/[pid]/ns/ directory…

getitimer, setitimer – get or set value of an interval timer Synopsis#include <sys/time.h> int getitimer(int which, struct itimerval *curr_value); int setitimer(int which, const struct itimerval *new_value, struct itimerval *old_value);DescriptionThese system calls provide access to interval timers, that is, timers that initially expire at some point in the future, and (optionally) at regular intervals after that….

gethostname, sethostname – get/set hostname Synopsis#include <unistd.h> int gethostname(char *name, size_t len); int sethostname(const char *name, size_t len); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): gethostname(): Since glibc 2.12: _BSD_SOURCE || _XOPEN_SOURCE >= 500 || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200112L sethostname(): Since glibc 2.21: _DEFAULT_SOURCE In glibc 2.19 and 2.20: _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)…

gethostid, sethostid – get or set the unique identifier of the current host Synopsis#include <unistd.h> long gethostid(void); int sethostid(long hostid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): gethostid(): _BSD_SOURCE || _XOPEN_SOURCE >= 500 sethostid(): Since glibc 2.21: _DEFAULT_SOURCE In glibc 2.19 and 2.20: _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) Up to and including glibc 2.19: _BSD_SOURCE ||…

getgroups, setgroups – get/set list of supplementary group IDs Synopsis#include <sys/types.h> #include <unistd.h> int getgroups(int size, gid_t list[]); #include <grp.h> int setgroups(size_t size, const gid_t *list); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): setgroups():     Since glibc 2.19:         _DEFAULT_SOURCE     Glibc 2.19 and earlier:         _BSD_SOURCE Descriptiongetgroups() returns the supplementary group IDs of the calling process in…

getgroups, setgroups – get/set list of supplementary group IDs Synopsis#include <sys/types.h> #include <unistd.h> int getgroups(int size, gid_t list[]); #include <grp.h> int setgroups(size_t size, const gid_t *list); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): setgroups():     Since glibc 2.19:         _DEFAULT_SOURCE     Glibc 2.19 and earlier:         _BSD_SOURCE Descriptiongetgroups() returns the supplementary group IDs of the calling process in…

setgid – set group identity Synopsis#include <sys/types.h> #include <unistd.h> int setgid(gid_t gid); Descriptionsetgid() sets the effective group ID of the calling process. If the calling process is privileged (more precisely: has the CAP_SETGID capability in its user namespace), the real GID and saved set-group-ID are also set. Under Linux, setgid() is implemented like the POSIX…

setgid – set group identity Synopsis#include <sys/types.h> #include <unistd.h> int setgid(gid_t gid); Descriptionsetgid() sets the effective group ID of the calling process. If the calling process is privileged (more precisely: has the CAP_SETGID capability in its user namespace), the real GID and saved set-group-ID are also set. Under Linux, setgid() is implemented like the POSIX…