chiark / gitweb /
util.c: use read_one_line_file where possible
[elogind.git] / src / shared / util.c
index 2cf9fbe53e6f97c9b48e96f458d192741b185e10..c824c3934e3dedc2c8cda61581fd0ee9b0ed1f1d 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"
@@ -436,8 +440,7 @@ 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 +453,9 @@ 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 +482,17 @@ 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 +556,7 @@ 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 +574,7 @@ 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 +693,7 @@ 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 +706,7 @@ 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)
@@ -2306,7 +2281,6 @@ 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 +2288,11 @@ 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 +2320,48 @@ char* dirname_malloc(const char *path) {
         return dir;
 }
 
-unsigned long long random_ull(void) {
+void random_bytes(void *p, size_t n) {
+        static bool srand_called = false;
         _cleanup_close_ int fd;
-        uint64_t ull;
-        ssize_t r;
+        ssize_t k;
+        uint8_t *q;
 
         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))
+        k = loop_read(fd, p, n, true);
+        if (k < 0 || (size_t) k != n)
                 goto fallback;
 
-        return ull;
+        return;
 
 fallback:
-        return random() * RAND_MAX + random();
-}
 
-unsigned random_u(void) {
-        _cleanup_close_ int fd;
-        unsigned u;
-        ssize_t r;
+        if (!srand_called) {
 
-        fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
-        if (fd < 0)
-                goto fallback;
+#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... */
 
-        r = loop_read(fd, &u, sizeof(u), true);
-        if (r != sizeof(u))
-                goto fallback;
+                void *auxv;
 
-        return u;
+                auxv = (void*) getauxval(AT_RANDOM);
+                if (auxv)
+                        srand(*(unsigned*) auxv);
+                else
+#endif
+                        srand(time(NULL) + gettid());
 
-fallback:
-        return random() * RAND_MAX + random();
+                srand_called = true;
+        }
+
+        /* If some idiot made /dev/urandom unavailable to us, he'll
+         * get a PRNG instead. */
+        for (q = p; q < (uint8_t*) p + n; q ++)
+                *q = rand();
 }
 
 void rename_process(const char name[8]) {
@@ -2533,24 +2513,17 @@ 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 +2633,15 @@ 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;
                 }
 
@@ -4137,7 +4111,7 @@ 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 +4128,10 @@ 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 +4459,11 @@ 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 +5059,7 @@ 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 +5586,14 @@ 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 +5955,20 @@ 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 +6068,76 @@ 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;
+}