From 707b66c66381c899d7ef640e158ffdd5bcff4deb Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 4 Sep 2015 09:05:52 +0200 Subject: [PATCH] sd-login: rework error handling Makre sure we always return sensible errors for the various, following the same rules, and document them in a comment in sd-login.c. Also, update all relevant man pages accordingly. --- man/sd_get_seats.xml | 23 ++++ man/sd_login_monitor_new.xml | 37 ++++-- man/sd_machine_get_class.xml | 31 ++++- man/sd_pid_get_session.xml | 38 ++++-- man/sd_seat_get_active.xml | 37 ++++++ man/sd_session_is_active.xml | 37 ++++++ man/sd_uid_get_state.xml | 39 ++++++ src/libsystemd/sd-login/sd-login.c | 178 +++++++++++++++------------ src/libsystemd/sd-login/test-login.c | 8 +- 9 files changed, 325 insertions(+), 103 deletions(-) diff --git a/man/sd_get_seats.xml b/man/sd_get_seats.xml index 4390d36ebe..f1981f7ea2 100644 --- a/man/sd_get_seats.xml +++ b/man/sd_get_seats.xml @@ -115,6 +115,29 @@ errno-style error code. + + + Errors + + Returned errors may indicate the following problems: + + + + + -EINVAL + + An input parameter was invalid (out of range, + or NULL, where that's not accepted). + + + + -ENOMEM + + Memory allocation failed. + + + + Notes diff --git a/man/sd_login_monitor_new.xml b/man/sd_login_monitor_new.xml index a7b47a3207..a8854dd590 100644 --- a/man/sd_login_monitor_new.xml +++ b/man/sd_login_monitor_new.xml @@ -161,20 +161,20 @@ is no timeout to wait for this will fill in (uint64_t) -1 instead. Note that poll() takes a relative timeout in milliseconds rather than an absolute timeout - in microseconds. To convert the absolute 'us' timeout into + in microseconds. To convert the absolute 'µs' timeout into relative 'ms', use code like the following: uint64_t t; int msec; sd_login_monitor_get_timeout(m, &t); if (t == (uint64_t) -1) - msec = -1; + msec = -1; else { - struct timespec ts; - uint64_t n; - clock_getttime(CLOCK_MONOTONIC, &ts); - n = (uint64_t) ts.tv_sec * 1000000 + ts.tv_nsec / 1000; - msec = t > n ? (int) ((t - n + 999) / 1000) : 0; + struct timespec ts; + uint64_t n; + clock_getttime(CLOCK_MONOTONIC, &ts); + n = (uint64_t) ts.tv_sec * 1000000 + ts.tv_nsec / 1000; + msec = t > n ? (int) ((t - n + 999) / 1000) : 0; } The code above does not do any error checking for brevity's @@ -203,6 +203,29 @@ else { always returns NULL. + + Errors + + Returned errors may indicate the following problems: + + + + + -EINVAL + + An input parameter was invalid (out of range, + or NULL, where that's not accepted). The specified category to + watch is not known. + + + + -ENOMEM + + Memory allocation failed. + + + + Notes diff --git a/man/sd_machine_get_class.xml b/man/sd_machine_get_class.xml index 5b881ccea1..9ad7f3fc66 100644 --- a/man/sd_machine_get_class.xml +++ b/man/sd_machine_get_class.xml @@ -56,7 +56,7 @@ int sd_machine_get_class const char* machine - char *class + char **class @@ -98,6 +98,35 @@ code. + + Errors + + Returned errors may indicate the following problems: + + + + + -ENXIO + + The specified machine does not exist or is currently not running. + + + + + -EINVAL + + An input parameter was invalid (out of range, + or NULL, where that's not accepted). + + + + -ENOMEM + + Memory allocation failed. + + + + Notes diff --git a/man/sd_pid_get_session.xml b/man/sd_pid_get_session.xml index 9c6706caf8..903c143f36 100644 --- a/man/sd_pid_get_session.xml +++ b/man/sd_pid_get_session.xml @@ -1,4 +1,4 @@ - + @@ -163,7 +163,7 @@ processes, user processes that are shared between multiple sessions of the same user, or kernel threads). For processes not being part of a login session this function will fail with - -ENXIO. The returned string needs to be freed with the libc + -ENODATA. The returned string needs to be freed with the libc free3 call after use. @@ -175,9 +175,9 @@ paths. Note that not all processes are part of a system unit/service (e.g. user processes, or kernel threads). For processes not being part of a systemd system unit this function - will fail with -ENXIO (More specifically: this call will not work - for kernel threads.) The returned string needs to be freed with - the libc free3 call after use. @@ -194,7 +194,7 @@ multiple login sessions of the same user, where sd_pid_get_session() will fail. For processes not being part of a login session and not being a shared process - of a user this function will fail with -ENXIO. + of a user this function will fail with -ENODATA. sd_pid_get_machine_name() may be used to determine the name of the VM or container is a member of. The @@ -203,7 +203,7 @@ free3 call after use. For processes not part of a VM or containers this - function fails with -ENXIO. + function fails with -ENODATA. sd_pid_get_slice() may be used to determine the slice unit the process is a member of. See @@ -251,7 +251,22 @@ - -ENXIO + -ESRCH + + The specified PID does not refer to a running + process. + + + + + -BADF + + The specified socket file descriptor was + invalid. + + + + -ENODATA Given field is not specified for the described process or peer. @@ -259,11 +274,10 @@ - -ESRCH + -EINVAL - The specified PID does not refer to a running - process. - + An input parameter was invalid (out of range, + or NULL, where that's not accepted). diff --git a/man/sd_seat_get_active.xml b/man/sd_seat_get_active.xml index 3c57ec9ea4..4d3e0822e0 100644 --- a/man/sd_seat_get_active.xml +++ b/man/sd_seat_get_active.xml @@ -148,6 +148,43 @@ errno-style error code. + + Errors + + Returned errors may indicate the following problems: + + + + + -ENODATA + + Given field is not specified for the described + seat. + + + + + -ENXIO + + The specified seat is unknown. + + + + + -EINVAL + + An input parameter was invalid (out of range, + or NULL, where that's not accepted). + + + + -ENOMEM + + Memory allocation failed. + + + + Notes diff --git a/man/sd_session_is_active.xml b/man/sd_session_is_active.xml index 4ca3a6c150..7de9523789 100644 --- a/man/sd_session_is_active.xml +++ b/man/sd_session_is_active.xml @@ -289,6 +289,43 @@ negative errno-style error code. + + Errors + + Returned errors may indicate the following problems: + + + + + -ENXIO + + The specified session does not exist. + + + + + -ENODATA + + Given field is not specified for the described + session. + + + + + -EINVAL + + An input parameter was invalid (out of range, + or NULL, where that's not accepted). + + + + -ENOMEM + + Memory allocation failed. + + + + Notes diff --git a/man/sd_uid_get_state.xml b/man/sd_uid_get_state.xml index b158f3528c..13ddf08c65 100644 --- a/man/sd_uid_get_state.xml +++ b/man/sd_uid_get_state.xml @@ -169,6 +169,45 @@ errno-style error code. + + Errors + + Returned errors may indicate the following problems: + + + + + -ENODATA + + Given field is not specified for the described + user. + + + + + -ENXIO + + The specified seat is unknown. + + + + + -EINVAL + + An input parameter was invalid (out of range, + or NULL, where that's not accepted). This is also returned if + the passed user ID is 0xFFFF or 0xFFFFFFFF, which are + undefined on Linux. + + + + -ENOMEM + + Memory allocation failed. + + + + Notes diff --git a/src/libsystemd/sd-login/sd-login.c b/src/libsystemd/sd-login/sd-login.c index 6300162ebe..180bdd09ad 100644 --- a/src/libsystemd/sd-login/sd-login.c +++ b/src/libsystemd/sd-login/sd-login.c @@ -35,6 +35,16 @@ #include "hostname-util.h" #include "sd-login.h" +/* Error codes: + * + * invalid input parameters → -EINVAL + * invalid fd → -EBADF + * process does not exist → -ESRCH + * cgroup does not exist → -ENOENT + * machine, session does not exist → -ENXIO + * requested metadata on object is missing → -ENODATA + */ + _public_ int sd_pid_get_session(pid_t pid, char **session) { assert_return(pid >= 0, -EINVAL); @@ -190,6 +200,8 @@ _public_ int sd_peer_get_user_slice(int fd, char **slice) { } static int file_of_uid(uid_t uid, char **p) { + + assert_return(uid_is_valid(uid), -EINVAL); assert(p); if (asprintf(p, "/run/systemd/users/" UID_FMT, uid) < 0) @@ -203,7 +215,6 @@ _public_ int sd_uid_get_state(uid_t uid, char**state) { char *s = NULL; int r; - assert_return(uid_is_valid(uid), -EINVAL); assert_return(state, -EINVAL); r = file_of_uid(uid, &p); @@ -217,11 +228,15 @@ _public_ int sd_uid_get_state(uid_t uid, char**state) { if (!s) return -ENOMEM; - } else if (r < 0) { + } + if (r < 0) { free(s); return r; - } else if (!s) + } + if (isempty(s)) { + free(s); return -EIO; + } *state = s; return 0; @@ -231,7 +246,6 @@ _public_ int sd_uid_get_display(uid_t uid, char **session) { _cleanup_free_ char *p = NULL, *s = NULL; int r; - assert_return(uid_is_valid(uid), -EINVAL); assert_return(session, -EINVAL); r = file_of_uid(uid, &p); @@ -240,12 +254,11 @@ _public_ int sd_uid_get_display(uid_t uid, char **session) { r = parse_env_file(p, NEWLINE, "DISPLAY", &s, NULL); if (r == -ENOENT) - return -ENXIO; + return -ENODATA; if (r < 0) return r; - if (isempty(s)) - return -ENXIO; + return -ENODATA; *session = s; s = NULL; @@ -253,6 +266,35 @@ _public_ int sd_uid_get_display(uid_t uid, char **session) { return 0; } +static int file_of_seat(const char *seat, char **_p) { + char *p; + int r; + + assert(_p); + + if (seat) { + if (!filename_is_valid(seat)) + return -EINVAL; + + p = strappend("/run/systemd/seats/", seat); + } else { + _cleanup_free_ char *buf = NULL; + + r = sd_session_get_seat(NULL, &buf); + if (r < 0) + return r; + + p = strappend("/run/systemd/seats/", buf); + } + + if (!p) + return -ENOMEM; + + *_p = p; + p = NULL; + return 0; +} + _public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat) { _cleanup_free_ char *t = NULL, *s = NULL, *p = NULL; size_t l; @@ -260,29 +302,27 @@ _public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat) const char *word, *variable, *state; assert_return(uid_is_valid(uid), -EINVAL); - assert_return(seat, -EINVAL); - - variable = require_active ? "ACTIVE_UID" : "UIDS"; - - p = strappend("/run/systemd/seats/", seat); - if (!p) - return -ENOMEM; - - r = parse_env_file(p, NEWLINE, variable, &s, NULL); + r = file_of_seat(seat, &p); if (r < 0) return r; - if (!s) - return -EIO; + variable = require_active ? "ACTIVE_UID" : "UIDS"; + + r = parse_env_file(p, NEWLINE, variable, &s, NULL); + if (r == -ENOENT) + return 0; + if (r < 0) + return r; + if (isempty(s)) + return 0; if (asprintf(&t, UID_FMT, uid) < 0) return -ENOMEM; - FOREACH_WORD(word, l, s, state) { + FOREACH_WORD(word, l, s, state) if (strneq(t, word, l)) return 1; - } return 0; } @@ -292,33 +332,22 @@ static int uid_get_array(uid_t uid, const char *variable, char ***array) { char **a; int r; - assert_return(uid_is_valid(uid), -EINVAL); + assert(variable); r = file_of_uid(uid, &p); if (r < 0) return r; - r = parse_env_file(p, NEWLINE, - variable, &s, - NULL); - if (r < 0) { - if (r == -ENOENT) { - if (array) - *array = NULL; - return 0; - } - - return r; - } - - if (!s) { + r = parse_env_file(p, NEWLINE, variable, &s, NULL); + if (r == -ENOENT || (r >= 0 && isempty(s))) { if (array) *array = NULL; return 0; } + if (r < 0) + return r; a = strv_split(s, " "); - if (!a) return -ENOMEM; @@ -380,37 +409,39 @@ static int file_of_session(const char *session, char **_p) { } _public_ int sd_session_is_active(const char *session) { - int r; _cleanup_free_ char *p = NULL, *s = NULL; + int r; r = file_of_session(session, &p); if (r < 0) return r; r = parse_env_file(p, NEWLINE, "ACTIVE", &s, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; - - if (!s) + if (isempty(s)) return -EIO; return parse_boolean(s); } _public_ int sd_session_is_remote(const char *session) { - int r; _cleanup_free_ char *p = NULL, *s = NULL; + int r; r = file_of_session(session, &p); if (r < 0) return r; r = parse_env_file(p, NEWLINE, "REMOTE", &s, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; - - if (!s) - return -EIO; + if (isempty(s)) + return -ENODATA; return parse_boolean(s); } @@ -426,9 +457,11 @@ _public_ int sd_session_get_state(const char *session, char **state) { return r; r = parse_env_file(p, NEWLINE, "STATE", &s, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; - else if (!s) + if (isempty(s)) return -EIO; *state = s; @@ -448,10 +481,11 @@ _public_ int sd_session_get_uid(const char *session, uid_t *uid) { return r; r = parse_env_file(p, NEWLINE, "UID", &s, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; - - if (!s) + if (isempty(s)) return -EIO; return parse_uid(s, uid); @@ -462,17 +496,19 @@ static int session_get_string(const char *session, const char *field, char **val int r; assert_return(value, -EINVAL); + assert(field); r = file_of_session(session, &p); if (r < 0) return r; r = parse_env_file(p, NEWLINE, field, &s, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; - if (isempty(s)) - return -ENXIO; + return -ENODATA; *value = s; s = NULL; @@ -492,6 +528,8 @@ _public_ int sd_session_get_vt(const char *session, unsigned *vtnr) { unsigned u; int r; + assert_return(vtnr, -EINVAL); + r = session_get_string(session, "VTNR", &vtnr_string); if (r < 0) return r; @@ -547,32 +585,6 @@ _public_ int sd_session_get_remote_host(const char *session, char **remote_host) return session_get_string(session, "REMOTE_HOST", remote_host); } -static int file_of_seat(const char *seat, char **_p) { - char *p; - int r; - - assert(_p); - - if (seat) - p = strappend("/run/systemd/seats/", seat); - else { - _cleanup_free_ char *buf = NULL; - - r = sd_session_get_seat(NULL, &buf); - if (r < 0) - return r; - - p = strappend("/run/systemd/seats/", buf); - } - - if (!p) - return -ENOMEM; - - *_p = p; - p = NULL; - return 0; -} - _public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) { _cleanup_free_ char *p = NULL, *s = NULL, *t = NULL; int r; @@ -587,6 +599,8 @@ _public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) { "ACTIVE", &s, "ACTIVE_UID", &t, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; @@ -625,7 +639,8 @@ _public_ int sd_seat_get_sessions(const char *seat, char ***sessions, uid_t **ui "SESSIONS", &s, "ACTIVE_SESSIONS", &t, NULL); - + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; @@ -657,7 +672,6 @@ _public_ int sd_seat_get_sessions(const char *seat, char ***sessions, uid_t **ui return -ENOMEM; r = parse_uid(k, b + i); - if (r < 0) continue; @@ -688,7 +702,7 @@ static int seat_get_can(const char *seat, const char *variable) { _cleanup_free_ char *p = NULL, *s = NULL; int r; - assert_return(variable, -EINVAL); + assert(variable); r = file_of_seat(seat, &p); if (r < 0) @@ -697,10 +711,12 @@ static int seat_get_can(const char *seat, const char *variable) { r = parse_env_file(p, NEWLINE, variable, &s, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; - if (!s) - return 0; + if (isempty(s)) + return -ENODATA; return parse_boolean(s); } @@ -824,6 +840,8 @@ _public_ int sd_machine_get_class(const char *machine, char **class) { p = strjoina("/run/systemd/machines/", machine); r = parse_env_file(p, NEWLINE, "CLASS", &c, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; if (!c) @@ -847,6 +865,8 @@ _public_ int sd_machine_get_ifindices(const char *machine, int **ifindices) { p = strjoina("/run/systemd/machines/", machine); r = parse_env_file(p, NEWLINE, "NETIF", &netif, NULL); + if (r == -ENOENT) + return -ENXIO; if (r < 0) return r; if (!netif) { diff --git a/src/libsystemd/sd-login/test-login.c b/src/libsystemd/sd-login/test-login.c index ddea7ffa14..70b0345848 100644 --- a/src/libsystemd/sd-login/test-login.c +++ b/src/libsystemd/sd-login/test-login.c @@ -52,7 +52,7 @@ static void test_login(void) { display_session = NULL; r = sd_uid_get_display(u2, &display_session); - assert_se(r >= 0 || r == -ENXIO); + assert_se(r >= 0 || r == -ENODATA); printf("user's display session = %s\n", strna(display_session)); free(display_session); @@ -108,19 +108,19 @@ static void test_login(void) { display = NULL; r = sd_session_get_display(session, &display); - assert_se(r >= 0 || r == -ENXIO); + assert_se(r >= 0 || r == -ENODATA); printf("display = %s\n", strna(display)); free(display); remote_user = NULL; r = sd_session_get_remote_user(session, &remote_user); - assert_se(r >= 0 || r == -ENXIO); + assert_se(r >= 0 || r == -ENODATA); printf("remote_user = %s\n", strna(remote_user)); free(remote_user); remote_host = NULL; r = sd_session_get_remote_host(session, &remote_host); - assert_se(r >= 0 || r == -ENXIO); + assert_se(r >= 0 || r == -ENODATA); printf("remote_host = %s\n", strna(remote_host)); free(remote_host);