diff options
Diffstat (limited to 'src/basic/process-util.c')
| -rw-r--r-- | src/basic/process-util.c | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/src/basic/process-util.c b/src/basic/process-util.c new file mode 100644 index 0000000000..cfc876567d --- /dev/null +++ b/src/basic/process-util.c @@ -0,0 +1,539 @@ +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <stdbool.h> +#include <sys/types.h> +#include <string.h> +#include <stdio.h> +#include <assert.h> +#include <errno.h> +#include <unistd.h> +#include <sys/wait.h> +#include <signal.h> +#include <ctype.h> + +#include "fileio.h" +#include "util.h" +#include "log.h" +#include "signal-util.h" +#include "process-util.h" + +int get_process_state(pid_t pid) { + const char *p; + char state; + int r; + _cleanup_free_ char *line = NULL; + + assert(pid >= 0); + + p = procfs_file_alloca(pid, "stat"); + r = read_one_line_file(p, &line); + if (r < 0) + return r; + + p = strrchr(line, ')'); + if (!p) + return -EIO; + + p++; + + if (sscanf(p, " %c", &state) != 1) + return -EIO; + + return (unsigned char) state; +} + +int get_process_comm(pid_t pid, char **name) { + const char *p; + int r; + + assert(name); + assert(pid >= 0); + + p = procfs_file_alloca(pid, "comm"); + + r = read_one_line_file(p, name); + if (r == -ENOENT) + return -ESRCH; + + return r; +} + +int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) { + _cleanup_fclose_ FILE *f = NULL; + char *r = NULL, *k; + const char *p; + int c; + + assert(line); + assert(pid >= 0); + + p = procfs_file_alloca(pid, "cmdline"); + + f = fopen(p, "re"); + if (!f) + return -errno; + + if (max_length == 0) { + size_t len = 0, allocated = 0; + + while ((c = getc(f)) != EOF) { + + if (!GREEDY_REALLOC(r, allocated, len+2)) { + free(r); + return -ENOMEM; + } + + r[len++] = isprint(c) ? c : ' '; + } + + if (len > 0) + r[len-1] = 0; + + } else { + bool space = false; + size_t left; + + r = new(char, max_length); + if (!r) + return -ENOMEM; + + k = r; + left = max_length; + while ((c = getc(f)) != EOF) { + + if (isprint(c)) { + if (space) { + if (left <= 4) + break; + + *(k++) = ' '; + left--; + space = false; + } + + if (left <= 4) + break; + + *(k++) = (char) c; + left--; + } else + space = true; + } + + if (left <= 4) { + size_t n = MIN(left-1, 3U); + memcpy(k, "...", n); + k[n] = 0; + } else + *k = 0; + } + + /* Kernel threads have no argv[] */ + if (isempty(r)) { + _cleanup_free_ char *t = NULL; + int h; + + free(r); + + if (!comm_fallback) + return -ENOENT; + + h = get_process_comm(pid, &t); + if (h < 0) + return h; + + r = strjoin("[", t, "]", NULL); + if (!r) + return -ENOMEM; + } + + *line = r; + return 0; +} + +int is_kernel_thread(pid_t pid) { + const char *p; + size_t count; + char c; + bool eof; + FILE *f; + + if (pid == 0) + return 0; + + assert(pid > 0); + + p = procfs_file_alloca(pid, "cmdline"); + f = fopen(p, "re"); + if (!f) + return -errno; + + count = fread(&c, 1, 1, f); + eof = feof(f); + fclose(f); + + /* Kernel threads have an empty cmdline */ + + if (count <= 0) + return eof ? 1 : -errno; + + return 0; +} + +int get_process_capeff(pid_t pid, char **capeff) { + const char *p; + + assert(capeff); + assert(pid >= 0); + + p = procfs_file_alloca(pid, "status"); + + return get_status_field(p, "\nCapEff:", capeff); +} + +static int get_process_link_contents(const char *proc_file, char **name) { + int r; + + assert(proc_file); + assert(name); + + r = readlink_malloc(proc_file, name); + if (r < 0) + return r == -ENOENT ? -ESRCH : r; + + return 0; +} + +int get_process_exe(pid_t pid, char **name) { + const char *p; + char *d; + int r; + + assert(pid >= 0); + + p = procfs_file_alloca(pid, "exe"); + r = get_process_link_contents(p, name); + if (r < 0) + return r; + + d = endswith(*name, " (deleted)"); + if (d) + *d = '\0'; + + return 0; +} + +static int get_process_id(pid_t pid, const char *field, uid_t *uid) { + _cleanup_fclose_ FILE *f = NULL; + char line[LINE_MAX]; + const char *p; + + assert(field); + assert(uid); + + if (pid == 0) + return getuid(); + + p = procfs_file_alloca(pid, "status"); + f = fopen(p, "re"); + if (!f) + return -errno; + + FOREACH_LINE(line, f, return -errno) { + char *l; + + l = strstrip(line); + + if (startswith(l, field)) { + l += strlen(field); + l += strspn(l, WHITESPACE); + + l[strcspn(l, WHITESPACE)] = 0; + + return parse_uid(l, uid); + } + } + + return -EIO; +} + +int get_process_uid(pid_t pid, uid_t *uid) { + return get_process_id(pid, "Uid:", uid); +} + +int get_process_gid(pid_t pid, gid_t *gid) { + assert_cc(sizeof(uid_t) == sizeof(gid_t)); + return get_process_id(pid, "Gid:", gid); +} + +int get_process_cwd(pid_t pid, char **cwd) { + const char *p; + + assert(pid >= 0); + + p = procfs_file_alloca(pid, "cwd"); + + return get_process_link_contents(p, cwd); +} + +int get_process_root(pid_t pid, char **root) { + const char *p; + + assert(pid >= 0); + + p = procfs_file_alloca(pid, "root"); + + return get_process_link_contents(p, root); +} + +int get_process_environ(pid_t pid, char **env) { + _cleanup_fclose_ FILE *f = NULL; + _cleanup_free_ char *outcome = NULL; + int c; + const char *p; + size_t allocated = 0, sz = 0; + + assert(pid >= 0); + assert(env); + + p = procfs_file_alloca(pid, "environ"); + + f = fopen(p, "re"); + if (!f) + return -errno; + + while ((c = fgetc(f)) != EOF) { + if (!GREEDY_REALLOC(outcome, allocated, sz + 5)) + return -ENOMEM; + + if (c == '\0') + outcome[sz++] = '\n'; + else + sz += cescape_char(c, outcome + sz); + } + + outcome[sz] = '\0'; + *env = outcome; + outcome = NULL; + + return 0; +} + +int get_parent_of_pid(pid_t pid, pid_t *_ppid) { + int r; + _cleanup_free_ char *line = NULL; + long unsigned ppid; + const char *p; + + assert(pid >= 0); + assert(_ppid); + + if (pid == 0) { + *_ppid = getppid(); + return 0; + } + + p = procfs_file_alloca(pid, "stat"); + r = read_one_line_file(p, &line); + if (r < 0) + return r; + + /* Let's skip the pid and comm fields. The latter is enclosed + * in () but does not escape any () in its value, so let's + * skip over it manually */ + + p = strrchr(line, ')'); + if (!p) + return -EIO; + + p++; + + if (sscanf(p, " " + "%*c " /* state */ + "%lu ", /* ppid */ + &ppid) != 1) + return -EIO; + + if ((long unsigned) (pid_t) ppid != ppid) + return -ERANGE; + + *_ppid = (pid_t) ppid; + + return 0; +} + +int wait_for_terminate(pid_t pid, siginfo_t *status) { + siginfo_t dummy; + + assert(pid >= 1); + + if (!status) + status = &dummy; + + for (;;) { + zero(*status); + + if (waitid(P_PID, pid, status, WEXITED) < 0) { + + if (errno == EINTR) + continue; + + return -errno; + } + + return 0; + } +} + +/* + * Return values: + * < 0 : wait_for_terminate() failed to get the state of the + * process, the process was terminated by a signal, or + * failed for an unknown reason. + * >=0 : The process terminated normally, and its exit code is + * returned. + * + * That is, success is indicated by a return value of zero, and an + * error is indicated by a non-zero value. + * + * A warning is emitted if the process terminates abnormally, + * and also if it returns non-zero unless check_exit_code is true. + */ +int wait_for_terminate_and_warn(const char *name, pid_t pid, bool check_exit_code) { + int r; + siginfo_t status; + + assert(name); + assert(pid > 1); + + r = wait_for_terminate(pid, &status); + if (r < 0) + return log_warning_errno(r, "Failed to wait for %s: %m", name); + + if (status.si_code == CLD_EXITED) { + if (status.si_status != 0) + log_full(check_exit_code ? LOG_WARNING : LOG_DEBUG, + "%s failed with error code %i.", name, status.si_status); + else + log_debug("%s succeeded.", name); + + return status.si_status; + } else if (status.si_code == CLD_KILLED || + status.si_code == CLD_DUMPED) { + + log_warning("%s terminated by signal %s.", name, signal_to_string(status.si_status)); + return -EPROTO; + } + + log_warning("%s failed due to unknown reason.", name); + return -EPROTO; +} + +int kill_and_sigcont(pid_t pid, int sig) { + int r; + + r = kill(pid, sig) < 0 ? -errno : 0; + + if (r >= 0) + kill(pid, SIGCONT); + + return r; +} + +int getenv_for_pid(pid_t pid, const char *field, char **_value) { + _cleanup_fclose_ FILE *f = NULL; + char *value = NULL; + int r; + bool done = false; + size_t l; + const char *path; + + assert(pid >= 0); + assert(field); + assert(_value); + + path = procfs_file_alloca(pid, "environ"); + + f = fopen(path, "re"); + if (!f) + return -errno; + + l = strlen(field); + r = 0; + + do { + char line[LINE_MAX]; + unsigned i; + + for (i = 0; i < sizeof(line)-1; i++) { + int c; + + c = getc(f); + if (_unlikely_(c == EOF)) { + done = true; + break; + } else if (c == 0) + break; + + line[i] = c; + } + line[i] = 0; + + if (memcmp(line, field, l) == 0 && line[l] == '=') { + value = strdup(line + l + 1); + if (!value) + return -ENOMEM; + + r = 1; + break; + } + + } while (!done); + + *_value = value; + return r; +} + +bool pid_is_unwaited(pid_t pid) { + /* Checks whether a PID is still valid at all, including a zombie */ + + if (pid <= 0) + return false; + + if (kill(pid, 0) >= 0) + return true; + + return errno != ESRCH; +} + +bool pid_is_alive(pid_t pid) { + int r; + + /* Checks whether a PID is still valid and not a zombie */ + + if (pid <= 0) + return false; + + r = get_process_state(pid); + if (r == -ENOENT || r == 'Z') + return false; + + return true; +} |