chiark / gitweb /
Base mkostemp_safe on mkostemp
[elogind.git] / src / shared / util.c
index 80dbf73c947d4f501503b2cc3626f28c8afff289..4c5b0482869f3b64633bbb9ef2f66fab6e9c46c7 100644 (file)
 #include <libgen.h>
 #undef basename
 
+#ifdef HAVE_SYS_AUXV_H
+#include <sys/auxv.h>
+#endif
+
 #include "macro.h"
 #include "util.h"
 #include "ioprio.h"
@@ -355,8 +359,23 @@ int safe_atod(const char *s, double *ret_d) {
         return 0;
 }
 
+static size_t strcspn_escaped(const char *s, const char *reject) {
+        bool escaped = false;
+        size_t n;
+
+        for (n=0; s[n]; n++) {
+                if (escaped)
+                        escaped = false;
+                else if (s[n] == '\\')
+                        escaped = true;
+                else if (strchr(reject, s[n]))
+                        return n;
+        }
+        return n;
+}
+
 /* Split a string into words. */
-char *split(const char *c, size_t *l, const char *separator, char **state) {
+char *split(const char *c, size_t *l, const char *separator, bool quoted, char **state) {
         char *current;
 
         current = *state ? *state : (char*) c;
@@ -365,70 +384,19 @@ char *split(const char *c, size_t *l, const char *separator, char **state) {
                 return NULL;
 
         current += strspn(current, separator);
-        *l = strcspn(current, separator);
-        *state = current+*l;
-
-        return (char*) current;
-}
-
-/* Split a string into words, but consider strings enclosed in '' and
- * "" as words even if they include spaces. */
-char *split_quoted(const char *c, size_t *l, char **state) {
-        const char *current, *e;
-        bool escaped = false;
-
-        assert(c);
-        assert(l);
-        assert(state);
-
-        current = *state ? *state : c;
-
-        current += strspn(current, WHITESPACE);
-
-        if (*current == 0)
+        if (!*current)
                 return NULL;
 
-        else if (*current == '\'') {
-                current ++;
-
-                for (e = current; *e; e++) {
-                        if (escaped)
-                                escaped = false;
-                        else if (*e == '\\')
-                                escaped = true;
-                        else if (*e == '\'')
-                                break;
-                }
-
-                *l = e-current;
-                *state = (char*) (*e == 0 ? e : e+1);
-
-        } else if (*current == '\"') {
-                current ++;
-
-                for (e = current; *e; e++) {
-                        if (escaped)
-                                escaped = false;
-                        else if (*e == '\\')
-                                escaped = true;
-                        else if (*e == '\"')
-                                break;
-                }
-
-                *l = e-current;
-                *state = (char*) (*e == 0 ? e : e+1);
-
+        if (quoted && strchr("\'\"", *current)) {
+                char quotechar = *(current++);
+                *l = strcspn_escaped(current, (char[]){quotechar, '\0'});
+                *state = current+*l+1;
+        } else if (quoted) {
+                *l = strcspn_escaped(current, separator);
+                *state = current+*l;
         } else {
-                for (e = current; *e; e++) {
-                        if (escaped)
-                                escaped = false;
-                        else if (*e == '\\')
-                                escaped = true;
-                        else if (strchr(WHITESPACE, *e))
-                                break;
-                }
-                *l = e-current;
-                *state = (char*) e;
+                *l = strcspn(current, separator);
+                *state = current+*l;
         }
 
         return (char*) current;
@@ -436,8 +404,7 @@ char *split_quoted(const char *c, size_t *l, char **state) {
 
 int get_parent_of_pid(pid_t pid, pid_t *_ppid) {
         int r;
-        _cleanup_fclose_ FILE *f = NULL;
-        char line[LINE_MAX];
+        _cleanup_free_ char *line = NULL;
         long unsigned ppid;
         const char *p;
 
@@ -450,14 +417,9 @@ int get_parent_of_pid(pid_t pid, pid_t *_ppid) {
         }
 
         p = procfs_file_alloca(pid, "stat");
-        f = fopen(p, "re");
-        if (!f)
-                return -errno;
-
-        if (!fgets(line, sizeof(line), f)) {
-                r = feof(f) ? -EIO : -errno;
+        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
@@ -484,28 +446,17 @@ int get_parent_of_pid(pid_t pid, pid_t *_ppid) {
 }
 
 int get_starttime_of_pid(pid_t pid, unsigned long long *st) {
-        _cleanup_fclose_ FILE *f = NULL;
-        char line[LINE_MAX];
+        int r;
+        _cleanup_free_ char *line = NULL;
         const char *p;
 
         assert(pid >= 0);
         assert(st);
 
-        if (pid == 0)
-                p = "/proc/self/stat";
-        else
-                p = procfs_file_alloca(pid, "stat");
-
-        f = fopen(p, "re");
-        if (!f)
-                return errno == ENOENT ? -ESRCH : -errno;
-
-        if (!fgets(line, sizeof(line), f)) {
-                if (ferror(f))
-                        return -errno;
-
-                return -EIO;
-        }
+        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
@@ -569,10 +520,7 @@ int get_process_comm(pid_t pid, char **name) {
         assert(name);
         assert(pid >= 0);
 
-        if (pid == 0)
-                p = "/proc/self/comm";
-        else
-                p = procfs_file_alloca(pid, "comm");
+        p = procfs_file_alloca(pid, "comm");
 
         r = read_one_line_file(p, name);
         if (r == -ENOENT)
@@ -590,10 +538,7 @@ int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char *
         assert(line);
         assert(pid >= 0);
 
-        if (pid == 0)
-                p = "/proc/self/cmdline";
-        else
-                p = procfs_file_alloca(pid, "cmdline");
+        p = procfs_file_alloca(pid, "cmdline");
 
         f = fopen(p, "re");
         if (!f)
@@ -712,10 +657,7 @@ int get_process_capeff(pid_t pid, char **capeff) {
         assert(capeff);
         assert(pid >= 0);
 
-        if (pid == 0)
-                p = "/proc/self/status";
-        else
-                p = procfs_file_alloca(pid, "status");
+        p = procfs_file_alloca(pid, "status");
 
         return get_status_field(p, "\nCapEff:", capeff);
 }
@@ -728,10 +670,7 @@ int get_process_exe(pid_t pid, char **name) {
         assert(pid >= 0);
         assert(name);
 
-        if (pid == 0)
-                p = "/proc/self/exe";
-        else
-                p = procfs_file_alloca(pid, "exe");
+        p = procfs_file_alloca(pid, "exe");
 
         r = readlink_malloc(p, name);
         if (r < 0)
@@ -2098,45 +2037,31 @@ int close_pipe(int p[]) {
 }
 
 ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
-        uint8_t *p;
+        uint8_t *p = buf;
         ssize_t n = 0;
 
         assert(fd >= 0);
         assert(buf);
 
-        p = buf;
-
         while (nbytes > 0) {
                 ssize_t k;
 
-                if ((k = read(fd, p, nbytes)) <= 0) {
-
-                        if (k < 0 && errno == EINTR)
-                                continue;
-
-                        if (k < 0 && errno == EAGAIN && do_poll) {
-                                struct pollfd pollfd = {
-                                        .fd = fd,
-                                        .events = POLLIN,
-                                };
-
-                                if (poll(&pollfd, 1, -1) < 0) {
-                                        if (errno == EINTR)
-                                                continue;
+                k = read(fd, p, nbytes);
+                if (k < 0 && errno == EINTR)
+                        continue;
 
-                                        return n > 0 ? n : -errno;
-                                }
+                if (k < 0 && errno == EAGAIN && do_poll) {
 
-                                /* We knowingly ignore the revents value here,
-                                 * and expect that any error/EOF is reported
-                                 * via read()/write()
-                                 */
+                        /* We knowingly ignore any return value here,
+                         * and expect that any error/EOF is reported
+                         * via read() */
 
-                                continue;
-                        }
+                        fd_wait_for_event(fd, POLLIN, (usec_t) -1);
+                        continue;
+                }
 
+                if (k <= 0)
                         return n > 0 ? n : (k < 0 ? -errno : 0);
-                }
 
                 p += k;
                 nbytes -= k;
@@ -2147,46 +2072,31 @@ ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
 }
 
 ssize_t loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
-        const uint8_t *p;
+        const uint8_t *p = buf;
         ssize_t n = 0;
 
         assert(fd >= 0);
         assert(buf);
 
-        p = buf;
-
         while (nbytes > 0) {
                 ssize_t k;
 
                 k = write(fd, p, nbytes);
-                if (k <= 0) {
-
-                        if (k < 0 && errno == EINTR)
-                                continue;
-
-                        if (k < 0 && errno == EAGAIN && do_poll) {
-                                struct pollfd pollfd = {
-                                        .fd = fd,
-                                        .events = POLLOUT,
-                                };
+                if (k < 0 && errno == EINTR)
+                        continue;
 
-                                if (poll(&pollfd, 1, -1) < 0) {
-                                        if (errno == EINTR)
-                                                continue;
+                if (k < 0 && errno == EAGAIN && do_poll) {
 
-                                        return n > 0 ? n : -errno;
-                                }
+                        /* We knowingly ignore any return value here,
+                         * and expect that any error/EOF is reported
+                         * via write() */
 
-                                /* We knowingly ignore the revents value here,
-                                 * and expect that any error/EOF is reported
-                                 * via read()/write()
-                                 */
-
-                                continue;
-                        }
+                        fd_wait_for_event(fd, POLLOUT, (usec_t) -1);
+                        continue;
+                }
 
+                if (k <= 0)
                         return n > 0 ? n : (k < 0 ? -errno : 0);
-                }
 
                 p += k;
                 nbytes -= k;
@@ -2306,7 +2216,6 @@ bool is_device_path(const char *path) {
 
 int dir_is_empty(const char *path) {
         _cleanup_closedir_ DIR *d;
-        int r;
 
         d = opendir(path);
         if (!d)
@@ -2314,11 +2223,11 @@ int dir_is_empty(const char *path) {
 
         for (;;) {
                 struct dirent *de;
-                union dirent_storage buf;
 
-                r = readdir_r(d, &buf.de, &de);
-                if (r > 0)
-                        return -r;
+                errno = 0;
+                de = readdir(d);
+                if (!de && errno != 0)
+                        return -errno;
 
                 if (!de)
                         return 1;
@@ -2346,42 +2255,60 @@ char* dirname_malloc(const char *path) {
         return dir;
 }
 
-unsigned long long random_ull(void) {
+int dev_urandom(void *p, size_t n) {
         _cleanup_close_ int fd;
-        uint64_t ull;
-        ssize_t r;
+        ssize_t k;
 
         fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
         if (fd < 0)
-                goto fallback;
-
-        r = loop_read(fd, &ull, sizeof(ull), true);
-        if (r != sizeof(ull))
-                goto fallback;
+                return errno == ENOENT ? -ENOSYS : -errno;
 
-        return ull;
+        k = loop_read(fd, p, n, true);
+        if (k < 0)
+                return (int) k;
+        if ((size_t) k != n)
+                return -EIO;
 
-fallback:
-        return random() * RAND_MAX + random();
+        return 0;
 }
 
-unsigned random_u(void) {
-        _cleanup_close_ int fd;
-        unsigned u;
-        ssize_t r;
+void random_bytes(void *p, size_t n) {
+        static bool srand_called = false;
+        uint8_t *q;
+        int r;
 
-        fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
-        if (fd < 0)
-                goto fallback;
+        r = dev_urandom(p, n);
+        if (r >= 0)
+                return;
 
-        r = loop_read(fd, &u, sizeof(u), true);
-        if (r != sizeof(u))
-                goto fallback;
+        /* If some idiot made /dev/urandom unavailable to us, he'll
+         * get a PRNG instead. */
 
-        return u;
+        if (!srand_called) {
+                unsigned x = 0;
 
-fallback:
-        return random() * RAND_MAX + random();
+#ifdef HAVE_SYS_AUXV_H
+                /* The kernel provides us with a bit of entropy in
+                 * auxv, so let's try to make use of that to seed the
+                 * pseudo-random generator. It's better than
+                 * nothing... */
+
+                void *auxv;
+
+                auxv = (void*) getauxval(AT_RANDOM);
+                if (auxv)
+                        x ^= *(unsigned*) auxv;
+#endif
+
+                x ^= (unsigned) now(CLOCK_REALTIME);
+                x ^= (unsigned) gettid();
+
+                srand(x);
+                srand_called = true;
+        }
+
+        for (q = p; q < (uint8_t*) p + n; q ++)
+                *q = rand();
 }
 
 void rename_process(const char name[8]) {
@@ -2533,24 +2460,17 @@ int getttyname_harder(int fd, char **r) {
 }
 
 int get_ctty_devnr(pid_t pid, dev_t *d) {
-        _cleanup_fclose_ FILE *f = NULL;
-        char line[LINE_MAX], *p;
+        int r;
+        _cleanup_free_ char *line = NULL;
+        const char *p;
         unsigned long ttynr;
-        const char *fn;
 
         assert(pid >= 0);
 
-        if (pid == 0)
-                fn = "/proc/self/stat";
-        else
-                fn = procfs_file_alloca(pid, "stat");
-
-        f = fopen(fn, "re");
-        if (!f)
-                return -errno;
-
-        if (!fgets(line, sizeof(line), f))
-                return feof(f) ? -EIO : -errno;
+        p = procfs_file_alloca(pid, "stat");
+        r = read_one_line_file(p, &line);
+        if (r < 0)
+                return r;
 
         p = strrchr(line, ')');
         if (!p)
@@ -2660,14 +2580,15 @@ int rm_rf_children_dangerous(int fd, bool only_dirs, bool honour_sticky, struct
 
         for (;;) {
                 struct dirent *de;
-                union dirent_storage buf;
                 bool is_dir, keep_around;
                 struct stat st;
                 int r;
 
-                r = readdir_r(d, &buf.de, &de);
-                if (r != 0 && ret == 0) {
-                        ret = -r;
+                errno = 0;
+                de = readdir(d);
+                if (!de && errno != 0) {
+                        if (ret == 0)
+                                ret = -errno;
                         break;
                 }
 
@@ -3469,7 +3390,7 @@ int wait_for_terminate_and_warn(const char *name, pid_t pid) {
         return -EPROTO;
 }
 
-_noreturn_ void freeze(void) {
+noreturn void freeze(void) {
 
         /* Make sure nobody waits for us on a socket anymore */
         close_all_fds(NULL, 0);
@@ -3914,12 +3835,13 @@ char* hostname_cleanup(char *s, bool lowercase) {
 }
 
 int pipe_eof(int fd) {
-        int r;
         struct pollfd pollfd = {
                 .fd = fd,
                 .events = POLLIN|POLLHUP,
         };
 
+        int r;
+
         r = poll(&pollfd, 1, 0);
         if (r < 0)
                 return -errno;
@@ -3931,13 +3853,16 @@ int pipe_eof(int fd) {
 }
 
 int fd_wait_for_event(int fd, int event, usec_t t) {
-        int r;
+
         struct pollfd pollfd = {
                 .fd = fd,
                 .events = event,
         };
 
-        r = poll(&pollfd, 1, t == (usec_t) -1 ? -1 : (int) (t / USEC_PER_MSEC));
+        struct timespec ts;
+        int r;
+
+        r = ppoll(&pollfd, 1, t == (usec_t) -1 ? NULL : timespec_store(&ts, t), NULL);
         if (r < 0)
                 return -errno;
 
@@ -3968,7 +3893,7 @@ int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
         t[k] = '.';
         stpcpy(stpcpy(t+k+1, fn), "XXXXXX");
 
-        fd = mkostemp(t, O_WRONLY|O_CLOEXEC);
+        fd = mkostemp_safe(t, O_WRONLY|O_CLOEXEC);
         if (fd < 0) {
                 free(t);
                 return -errno;
@@ -4137,7 +4062,7 @@ int symlink_atomic(const char *from, const char *to) {
         _cleanup_free_ char *t;
         const char *fn;
         size_t k;
-        unsigned long long ull;
+        uint64_t u;
         unsigned i;
         int r;
 
@@ -4154,10 +4079,10 @@ int symlink_atomic(const char *from, const char *to) {
         t[k] = '.';
         x = stpcpy(t+k+1, fn);
 
-        ull = random_ull();
+        u = random_u64();
         for (i = 0; i < 16; i++) {
-                *(x++) = hexchar(ull & 0xF);
-                ull >>= 4;
+                *(x++) = hexchar(u & 0xF);
+                u >>= 4;
         }
 
         *x = 0;
@@ -4485,13 +4410,11 @@ int get_files_in_directory(const char *path, char ***list) {
 
         for (;;) {
                 struct dirent *de;
-                union dirent_storage buf;
-                int k;
 
-                k = readdir_r(d, &buf.de, &de);
-                assert(k >= 0);
-                if (k > 0)
-                        return -k;
+                errno = 0;
+                de = readdir(d);
+                if (!de && errno != 0)
+                        return -errno;
                 if (!de)
                         break;
 
@@ -5087,10 +5010,7 @@ int getenv_for_pid(pid_t pid, const char *field, char **_value) {
         assert(field);
         assert(_value);
 
-        if (pid == 0)
-                path = "/proc/self/environ";
-        else
-                path = procfs_file_alloca(pid, "environ");
+        path = procfs_file_alloca(pid, "environ");
 
         f = fopen(path, "re");
         if (!f)
@@ -5617,15 +5537,14 @@ int on_ac_power(void) {
 
         for (;;) {
                 struct dirent *de;
-                union dirent_storage buf;
                 _cleanup_close_ int fd = -1, device = -1;
                 char contents[6];
                 ssize_t n;
-                int k;
 
-                k = readdir_r(d, &buf.de, &de);
-                if (k != 0)
-                        return -k;
+                errno = 0;
+                de = readdir(d);
+                if (!de && errno != 0)
+                        return -errno;
 
                 if (!de)
                         break;
@@ -5987,8 +5906,20 @@ int proc_cmdline(char **ret) {
         int r;
 
         if (detect_container(NULL) > 0) {
-                *ret = NULL;
-                return 0;
+                char *buf, *p;
+                size_t sz = 0;
+
+                r = read_full_file("/proc/1/cmdline", &buf, &sz);
+                if (r < 0)
+                        return r;
+
+                for (p = buf; p + 1 < buf + sz; p++)
+                        if (*p == 0)
+                                *p = ' ';
+
+                *p  = 0;
+                *ret = buf;
+                return 1;
         }
 
         r = read_one_line_file("/proc/cmdline", ret);
@@ -6088,3 +6019,116 @@ int namespace_enter(int pidns_fd, int mntns_fd, int root_fd) {
 
         return 0;
 }
+
+bool pid_valid(pid_t pid) {
+        if (pid <= 0)
+                return false;
+
+        if (kill(pid, 0) >= 0)
+                return true;
+
+        return errno != ESRCH;
+}
+
+int getpeercred(int fd, struct ucred *ucred) {
+        socklen_t n = sizeof(struct ucred);
+        struct ucred u;
+        int r;
+
+        assert(fd >= 0);
+        assert(ucred);
+
+        r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &u, &n);
+        if (r < 0)
+                return -errno;
+
+        if (n != sizeof(struct ucred))
+                return -EIO;
+
+        /* Check if the data is actually useful and not suppressed due
+         * to namespacing issues */
+        if (u.pid <= 0)
+                return -ENODATA;
+
+        *ucred = u;
+        return 0;
+}
+
+int getpeersec(int fd, char **ret) {
+        socklen_t n = 64;
+        char *s;
+        int r;
+
+        assert(fd >= 0);
+        assert(ret);
+
+        s = new0(char, n);
+        if (!s)
+                return -ENOMEM;
+
+        r = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n);
+        if (r < 0) {
+                free(s);
+
+                if (errno != ERANGE)
+                        return -errno;
+
+                s = new0(char, n);
+                if (!s)
+                        return -ENOMEM;
+
+                r = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n);
+                if (r < 0) {
+                        free(s);
+                        return -errno;
+                }
+        }
+
+        if (isempty(s)) {
+                free(s);
+                return -ENOTSUP;
+        }
+
+        *ret = s;
+        return 0;
+}
+
+/* This is much like like mkostemp() but is subject to umask(). */
+int mkostemp_safe(char *pattern, int flags) {
+        _cleanup_umask_ mode_t u;
+        int fd;
+
+        assert(pattern);
+
+        u = umask(077);
+
+        fd = mkostemp(pattern, flags);
+        if (fd < 0)
+                return -errno;
+
+        return fd;
+}
+
+int open_tmpfile(const char *path, int flags) {
+        char *p;
+        int fd;
+
+        assert(path);
+
+#ifdef O_TMPFILE
+        /* Try O_TMPFILE first, if it is supported */
+        fd = open(path, flags|O_TMPFILE, S_IRUSR|S_IWUSR);
+        if (fd >= 0)
+                return fd;
+#endif
+
+        /* Fall back to unguessable name + unlinking */
+        p = strappenda(path, "/systemd-tmp-XXXXXX");
+
+        fd = mkostemp_safe(p, flags);
+        if (fd < 0)
+                return fd;
+
+        unlink(p);
+        return fd;
+}