util: add a bit of syntactic sugar for saving/restoring errno

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

diff --git a/src/shared/util.c b/src/shared/util.c
index 2241b79859ff16233f4a33e7f66aea13efb11464..b69e7e882a8803546e205e97cd63a99e76f1057b 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -207,14 +207,12 @@ int close_nointr(int fd) {
 }
 
 void close_nointr_nofail(int fd) {
-        int saved_errno = errno;
+        PROTECT_ERRNO;
 
         /* like close_nointr() but cannot fail, and guarantees errno
          * is unchanged */
 
         assert_se(close_nointr(fd) == 0);
-
-        errno = saved_errno;
 }
 
 void close_many(const int fds[], unsigned n_fd) {
@@ -1069,6 +1067,32 @@ char *hexmem(const void *p, size_t l) {
         return r;
 }
 
+void *unhexmem(const char *p, size_t l) {
+        uint8_t *r, *z;
+        const char *x;
+
+        assert(p);
+
+        z = r = malloc((l + 1) / 2 + 1);
+        if (!r)
+                return NULL;
+
+        for (x = p; x < p + l; x += 2) {
+                int a, b;
+
+                a = unhexchar(x[0]);
+                if (x+1 < p + l)
+                        b = unhexchar(x[1]);
+                else
+                        b = 0;
+
+                *(z++) = (uint8_t) a << 4 | (uint8_t) b;
+        }
+
+        *z = 0;
+        return r;
+}
+
 char octchar(int x) {
         return '0' + (x & 7);
 }
@@ -1847,18 +1871,18 @@ int flush_fd(int fd) {
                 ssize_t l;
                 int r;
 
-                if ((r = poll(&pollfd, 1, 0)) < 0) {
-
+                r = poll(&pollfd, 1, 0);
+                if (r < 0) {
                         if (errno == EINTR)
                                 continue;
 
                         return -errno;
-                }
 
-                if (r == 0)
+                } else if (r == 0)
                         return 0;
 
-                if ((l = read(fd, buf, sizeof(buf))) < 0) {
+                l = read(fd, buf, sizeof(buf));
+                if (l < 0) {
 
                         if (errno == EINTR)
                                 continue;
@@ -1867,9 +1891,7 @@ int flush_fd(int fd) {
                                 return 0;
 
                         return -errno;
-                }
-
-                if (l <= 0)
+                } else if (l == 0)
                         return 0;
         }
 }
@@ -2042,10 +2064,12 @@ fail:
 }
 
 int release_terminal(void) {
-        int r = 0, fd;
+        int r = 0;
         struct sigaction sa_old, sa_new;
+        int _cleanup_close_ fd;
 
-        if ((fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_NDELAY|O_CLOEXEC)) < 0)
+        fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_NDELAY|O_CLOEXEC);
+        if (fd < 0)
                 return -errno;
 
         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
@@ -2061,7 +2085,6 @@ int release_terminal(void) {
 
         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 
-        close_nointr_nofail(fd);
         return r;
 }
 
@@ -2265,7 +2288,7 @@ int parse_bytes(const char *t, off_t *bytes) {
                 errno = 0;
                 l = strtoll(p, &e, 10);
 
-                if (errno != 0)
+                if (errno > 0)
                         return -errno;
 
                 if (l < 0)
@@ -4191,7 +4214,7 @@ int get_user_creds(
         }
 
         if (!p)
-                return errno != 0 ? -errno : -ESRCH;
+                return errno > 0 ? -errno : -ESRCH;
 
         if (uid)
                 *uid = p->pw_uid;
@@ -4272,7 +4295,7 @@ int get_group_creds(const char **groupname, gid_t *gid) {
         }
 
         if (!g)
-                return errno != 0 ? -errno : -ESRCH;
+                return errno > 0 ? -errno : -ESRCH;
 
         if (gid)
                 *gid = g->gr_gid;
@@ -5829,3 +5852,20 @@ char *strrep(const char *s, unsigned n) {
         *p = 0;
         return r;
 }
+
+void* greedy_realloc(void **p, size_t *allocated, size_t need) {
+        size_t a;
+        void *q;
+
+        if (*allocated >= need)
+                return *p;
+
+        a = MAX(64u, need * 2);
+        q = realloc(*p, a);
+        if (!q)
+                return NULL;
+
+        *p = q;
+        *allocated = a;
+        return q;
+}