util: unify SO_PEERCRED/SO_PEERSEC invocations

[elogind.git] / src / shared / util.c

diff --git a/src/shared/util.c b/src/shared/util.c
index 481c17245ddc1978cf4f52fb80fd6261a0484f3e..6b6722c2780200a62f128e24674ac27f68c7ba1a 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -61,6 +61,10 @@
 #include <libgen.h>
 #undef basename
 
+#ifdef HAVE_SYS_AUXV_H
+#include <sys/auxv.h>
+#endif
+
 #include "macro.h"
 #include "util.h"
 #include "ioprio.h"
@@ -2345,42 +2349,48 @@ 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;
+
+                auxv = (void*) getauxval(AT_RANDOM);
+                if (auxv)
+                        srand(*(unsigned*) auxv);
+                else
+#endif
+                        srand(time(NULL) + gettid());
 
-        return u;
+                srand_called = true;
+        }
 
-fallback:
-        return random() * RAND_MAX + random();
+        /* 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]) {
@@ -4137,7 +4147,7 @@ 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 +4164,10 @@ 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;
@@ -5984,8 +5994,20 @@ 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);
@@ -6095,3 +6117,61 @@ bool pid_valid(pid_t pid) {
 
         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;
+                }
+        }
+
+        *ret = s;
+        return 0;
+}