Convert read and write operations to sss_atomic_read

https://fedorahosted.org/sssd/ticket/1209

4 files changed, 89 insertions, 120 deletions

diff --git a/src/util/backup_file.c b/src/util/backup_file.c
index ba7764049..edbf868cb 100644
--- a/src/util/backup_file.c
+++ b/src/util/backup_file.c
@@ -33,9 +33,8 @@ int backup_file(const char *src_file, int dbglvl)
     int src_fd = -1;
     int dst_fd = -1;
     char *dst_file;
-    ssize_t count;
-    ssize_t num;
-    ssize_t pos;
+    ssize_t numread;
+    ssize_t written;
     int ret, i;
 
     src_fd = open(src_file, O_RDONLY);
@@ -84,31 +83,30 @@ int backup_file(const char *src_file, int dbglvl)
 
     /* copy file contents */
     while (1) {
-        num = read(src_fd, buf, BUFFER_SIZE);
-        if (num < 0) {
-            if (errno == EINTR || errno == EAGAIN) continue;
+        errno = 0;
+        numread = sss_atomic_read_s(src_fd, buf, BUFFER_SIZE);
+        if (numread < 0) {
             ret = errno;
             DEBUG(dbglvl, ("Error (%d [%s]) reading from source %s\n",
                            ret, strerror(ret), src_file));
             goto done;
         }
-        if (num == 0) break;
-
-        count = num;
-
-        pos = 0;
-        while (count > 0) {
-            errno = 0;
-            num = write(dst_fd, &buf[pos], count);
-            if (num < 0) {
-                if (errno == EINTR || errno == EAGAIN) continue;
-                ret = errno;
-                DEBUG(dbglvl, ("Error (%d [%s]) writing to destination %s\n",
-                               ret, strerror(ret), dst_file));
-                goto done;
-            }
-            pos += num;
-            count -= num;
+        if (numread == 0) break;
+
+        errno = 0;
+        written = sss_atomic_write_s(dst_fd, buf, numread);
+        if (written == -1) {
+            ret = errno;
+            DEBUG(dbglvl, ("Error (%d [%s]) writing to destination %s\n",
+                            ret, strerror(ret), dst_file));
+            goto done;
+        }
+
+        if (written != numread) {
+            DEBUG(dbglvl, ("Wrote %d bytes expected %d bytes\n",
+                  written, numread));
+            ret = EIO;
+            goto done;
         }
     }
 
diff --git a/src/util/child_common.c b/src/util/child_common.c
index 6214c7cc3..05f00b0f3 100644
--- a/src/util/child_common.c
+++ b/src/util/child_common.c
@@ -337,42 +337,36 @@ static void write_pipe_handler(struct tevent_context *ev,
     struct tevent_req *req = talloc_get_type(pvt, struct tevent_req);
     struct write_pipe_state *state = tevent_req_data(req,
                                                      struct write_pipe_state);
-    ssize_t size;
+    errno_t ret;
 
     if (flags & TEVENT_FD_READ) {
-        DEBUG(1, ("write_pipe_done called with TEVENT_FD_READ,"
-                  " this should not happen.\n"));
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("write_pipe_done called with TEVENT_FD_READ,"
+               " this should not happen.\n"));
         tevent_req_error(req, EINVAL);
         return;
     }
 
-    size = write(state->fd,
-                 state->buf + state->written,
-                 state->len - state->written);
-    if (size == -1) {
-        if (errno == EAGAIN || errno == EINTR) return;
-        DEBUG(1, ("write failed [%d][%s].\n", errno, strerror(errno)));
-        tevent_req_error(req, errno);
-        return;
-
-    } else if (size >= 0) {
-        state->written += size;
-        if (state->written > state->len) {
-            DEBUG(1, ("write to much, this should never happen.\n"));
-            tevent_req_error(req, EINVAL);
-            return;
-        }
-    } else {
-        DEBUG(1, ("unexpected return value of write [%d].\n", size));
-        tevent_req_error(req, EINVAL);
+    errno = 0;
+    state->written = sss_atomic_write_s(state->fd, state->buf, state->len);
+    if (state->written == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("write failed [%d][%s].\n", ret, strerror(ret)));
+        tevent_req_error(req, ret);
         return;
     }
 
-    if (state->len == state->written) {
-        DEBUG(6, ("All data has been sent!\n"));
-        tevent_req_done(req);
+    if (state->len != state->written) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Wrote %d bytes, expected %d\n",
+              state->written, state->len));
+        tevent_req_error(req, EIO);
         return;
     }
+
+    DEBUG(SSSDBG_TRACE_FUNC, ("All data has been sent!\n"));
+    tevent_req_done(req);
+    return;
 }
 
 int write_pipe_recv(struct tevent_req *req)
@@ -438,16 +432,13 @@ static void read_pipe_handler(struct tevent_context *ev,
         return;
     }
 
-    size = read(state->fd,
+    size = sss_atomic_read_s(state->fd,
                 buf,
                 CHILD_MSG_CHUNK);
     if (size == -1) {
         err = errno;
-        if (err == EAGAIN || err == EINTR) {
-            return;
-        }
-
-        DEBUG(1, ("read failed [%d][%s].\n", err, strerror(err)));
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("read failed [%d][%s].\n", err, strerror(err)));
         tevent_req_error(req, err);
         return;
 
diff --git a/src/util/find_uid.c b/src/util/find_uid.c
index 77b9f22a8..d34a4abd2 100644
--- a/src/util/find_uid.c
+++ b/src/util/find_uid.c
@@ -107,15 +107,13 @@ static errno_t get_uid_from_pid(const pid_t pid, uid_t *uid)
         goto fail_fd;
     }
 
-    while ((ret = read(fd, buf, BUFSIZE)) != 0) {
-        if (ret == -1) {
-            error = errno;
-            if (error == EINTR || error == EAGAIN) {
-                continue;
-            }
-            DEBUG(1, ("read failed [%d][%s].\n", error, strerror(error)));
-            goto fail_fd;
-        }
+    errno = 0;
+    ret = sss_atomic_read_s(fd, buf, BUFSIZE);
+    if (ret == -1) {
+        error = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("read failed [%d][%s].\n", error, strerror(error)));
+        goto fail_fd;
     }
 
     /* Guarantee NULL-termination in case we read the full BUFSIZE somehow */
diff --git a/src/util/server.c b/src/util/server.c
index 95b183632..39cc12776 100644
--- a/src/util/server.c
+++ b/src/util/server.c
@@ -117,51 +117,36 @@ int pidfile(const char *path, const char *name)
     fd = open(file, O_RDONLY, 0644);
     err = errno;
     if (fd != -1) {
-        len = 0;
-        while ((ret = read(fd, pid_str + len, pidlen - len)) != 0) {
-            if (ret == -1) {
-                if (errno == EINTR || errno == EAGAIN) {
-                    continue;
-                }
-                DEBUG(1, ("read failed [%d][%s].\n", errno, strerror(errno)));
-                break;
-            } else if (ret > 0) {
-                len += ret;
-                if (len > pidlen) {
-                    DEBUG(1, ("read too much, this should never happen.\n"));
-                    close(fd);
-                    talloc_free(file);
-                    return EINVAL;
-                }
-                continue;
-            } else {
-                DEBUG(1, ("unexpected return code of read [%d].\n", ret));
-                break;
-            }
+        errno = 0;
+        len = sss_atomic_read_s(fd, pid_str, pidlen);
+        ret = errno;
+        if (len == -1) {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  ("read failed [%d][%s].\n", ret, strerror(ret)));
+            close(fd);
+            talloc_free(file);
+            return EINVAL;
         }
 
         /* Ensure NULL-termination */
         pid_str[len] = '\0';
 
-        if (ret == 0) {
-            /* let's check the pid */
-
-            pid = (pid_t)atoi(pid_str);
-            if (pid != 0) {
-                errno = 0;
-                ret = kill(pid, 0);
-                /* succeeded in signaling the process -> another sssd process */
-                if (ret == 0) {
-                    close(fd);
-                    talloc_free(file);
-                    return EEXIST;
-                }
-                if (ret != 0 && errno != ESRCH) {
-                    err = errno;
-                    close(fd);
-                    talloc_free(file);
-                    return err;
-                }
+        /* let's check the pid */
+        pid = (pid_t)atoi(pid_str);
+        if (pid != 0) {
+            errno = 0;
+            ret = kill(pid, 0);
+            /* succeeded in signaling the process -> another sssd process */
+            if (ret == 0) {
+                close(fd);
+                talloc_free(file);
+                return EEXIST;
+            }
+            if (ret != 0 && errno != ESRCH) {
+                err = errno;
+                close(fd);
+                talloc_free(file);
+                return err;
             }
         }
 
@@ -188,25 +173,20 @@ int pidfile(const char *path, const char *name)
     snprintf(pid_str, sizeof(pid_str) -1, "%u\n", (unsigned int) getpid());
     size = strlen(pid_str);
 
-    written = 0;
-    while (written < size) {
-        ret = write(fd, pid_str+written, size-written);
-        if (ret == -1) {
-            err = errno;
-            if (err == EINTR || err == EAGAIN) {
-                continue;
-            }
-            DEBUG(1, ("write failed [%d][%s]\n", err, strerror(err)));
-            break;
-        }
-        else {
-            written += ret;
-        }
+    errno = 0;
+    written = sss_atomic_write_s(fd, pid_str, size);
+    if (ret == -1) {
+        err = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("write failed [%d][%s]\n", err, strerror(err)));
+        return err;
     }
 
     if (written != size) {
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("Wrote %d bytes expected %d\n", written, size));
         close(fd);
-        return err;
+        return EIO;
     }
 
     close(fd);
@@ -317,8 +297,10 @@ static void server_stdin_handler(struct tevent_context *event_ctx,
 {
 	const char *binary_name = (const char *)private;
 	uint8_t c;
-	if (read(0, &c, 1) == 0) {
-		DEBUG(0,("%s: EOF on stdin - terminating\n", binary_name));
+
+        errno = 0;
+        if (sss_atomic_read_s(0, &c, 1) == 0) {
+		DEBUG(SSSDBG_CRIT_FAILURE,("%s: EOF on stdin - terminating\n", binary_name));
 #if HAVE_GETPGRP
 		if (getpgrp() == getpid()) {
 			kill(-getpgrp(), SIGTERM);