Convert read and write operations to sss_atomic_read

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

16 files changed, 242 insertions, 314 deletions

diff --git a/Makefile.am b/Makefile.am
index 919fb9b25..8293c08ee 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -777,6 +777,7 @@ endif
 files_tests_SOURCES = \
     src/tests/files-tests.c \
     src/util/check_and_open.c \
+    src/util/atomic_io.c \
     src/tools/selinux.c \
     src/tools/files.c
 files_tests_CFLAGS = \
@@ -835,6 +836,7 @@ fail_over_tests_LDADD = \
 find_uid_tests_SOURCES = \
     src/tests/find_uid-tests.c \
     src/util/find_uid.c \
+    src/util/atomic_io.c \
     src/util/strtonum.c
 find_uid_tests_CFLAGS = \
     $(AM_CFLAGS) \
@@ -1225,6 +1227,7 @@ krb5_child_SOURCES = \
     src/providers/dp_pam_data_util.c \
     src/util/user_info_msg.c \
     src/util/sss_krb5.c \
+    src/util/atomic_io.c \
     src/util/util.c \
     src/util/signal.c
 krb5_child_CFLAGS = \
@@ -1243,6 +1246,7 @@ krb5_child_LDADD = \
 ldap_child_SOURCES = \
     src/providers/ldap/ldap_child.c \
     src/util/sss_krb5.c \
+    src/util/atomic_io.c \
     src/util/util.c \
     src/util/signal.c
 ldap_child_CFLAGS = \
@@ -1284,7 +1288,8 @@ memberof_la_LDFLAGS = \
 
 if BUILD_KRB5_LOCATOR_PLUGIN
 sssd_krb5_locator_plugin_la_SOURCES = \
-    src/krb5_plugin/sssd_krb5_locator_plugin.c
+    src/krb5_plugin/sssd_krb5_locator_plugin.c \
+    src/util/atomic_io.c
 sssd_krb5_locator_plugin_la_CFLAGS = \
     $(AM_CFLAGS) \
     $(KRB5_CFLAGS)
diff --git a/src/krb5_plugin/sssd_krb5_locator_plugin.c b/src/krb5_plugin/sssd_krb5_locator_plugin.c
index 3eced04d6..b8d4e31b6 100644
--- a/src/krb5_plugin/sssd_krb5_locator_plugin.c
+++ b/src/krb5_plugin/sssd_krb5_locator_plugin.c
@@ -86,7 +86,6 @@ static int get_krb5info(const char *realm, struct sssd_ctx *ctx,
     char *krb5info_name = NULL;
     size_t len;
     uint8_t buf[BUFSIZE + 1];
-    uint8_t *p;
     int fd = -1;
     const char *name_tmpl = NULL;
     char *port_str;
@@ -129,23 +128,19 @@ static int get_krb5info(const char *realm, struct sssd_ctx *ctx,
         goto done;
     }
 
-    len = BUFSIZE;
-    p = buf;
     memset(buf, 0, BUFSIZE+1);
-    while (len != 0 && (ret = read(fd, p, len)) != 0) {
-        if (ret == -1) {
-            if (errno == EINTR || errno == EAGAIN) continue;
-            PLUGIN_DEBUG(("read failed [%d][%s].\n", errno, strerror(errno)));
-            close(fd);
-            goto done;
-        }
 
-        len -= ret;
-        p += ret;
+    errno = 0;
+    len = sss_atomic_read_s(fd, buf, BUFSIZE);
+    if (len == -1) {
+        ret = errno;
+        PLUGIN_DEBUG(("read failed [%d][%s].\n", ret, strerror(ret)));
+        close(fd);
+        goto done;
     }
     close(fd);
 
-    if (len == 0) {
+    if (len == BUFSIZE) {
         PLUGIN_DEBUG(("Content of krb5info file [%s] is [%d] or larger.\n",
                       krb5info_name, BUFSIZE));
     }
@@ -212,6 +207,7 @@ static int get_krb5info(const char *realm, struct sssd_ctx *ctx,
             goto done;
     }
 
+    ret = 0;
 done:
     free(krb5info_name);
     return ret;
diff --git a/src/monitor/monitor.c b/src/monitor/monitor.c
index cadc27fe3..041f576e6 100644
--- a/src/monitor/monitor.c
+++ b/src/monitor/monitor.c
@@ -1498,11 +1498,12 @@ static void process_config_file(struct tevent_context *ev,
     struct inotify_event *in_event;
     char *buf;
     char *name;
-    ssize_t len, total_len;
+    ssize_t len;
     ssize_t event_size;
     struct config_file_ctx *file_ctx;
     struct config_file_callback *cb;
     struct rewatch_ctx *rw_ctx;
+    errno_t ret;
 
     event_size = sizeof(struct inotify_event);
     file_ctx = talloc_get_type(ptr, struct config_file_ctx);
@@ -1517,16 +1518,14 @@ static void process_config_file(struct tevent_context *ev,
         goto done;
     }
 
-    total_len = 0;
-    while (total_len < event_size) {
-        len = read(file_ctx->mt_ctx->inotify_fd, buf+total_len,
-                   event_size-total_len);
-        if (len == -1) {
-            if (errno == EINTR || errno == EAGAIN) continue;
-            DEBUG(0, ("Critical error reading inotify file descriptor.\n"));
-            goto done;
-        }
-        total_len += len;
+    errno = 0;
+    len = sss_atomic_read_s(file_ctx->mt_ctx->inotify_fd, buf, event_size);
+    if (len == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("Critical error reading inotify file descriptor [%d]: %s\n",
+               ret, strerror(ret)));
+        goto done;
     }
 
     in_event = (struct inotify_event *)buf;
@@ -1535,19 +1534,19 @@ static void process_config_file(struct tevent_context *ev,
         /* Read in the name, even though we don't use it,
          * so that read ptr is in the right place
          */
-        name = talloc_size(tmp_ctx, len);
+        name = talloc_size(tmp_ctx, in_event->len);
         if (!name) {
             goto done;
         }
-        total_len = 0;
-        while (total_len < in_event->len) {
-            len = read(file_ctx->mt_ctx->inotify_fd, &name, in_event->len);
-            if (len == -1) {
-                if (errno == EINTR || errno == EAGAIN) continue;
-                DEBUG(0, ("Critical error reading inotify file descriptor.\n"));
-                goto done;
-            }
-            total_len += len;
+
+        errno = 0;
+        len = sss_atomic_read_s(file_ctx->mt_ctx->inotify_fd, name, in_event->len);
+        if (len == -1) {
+            ret = errno;
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                ("Critical error reading inotify file descriptor [%d]: %s\n",
+                ret, strerror(ret)));
+            goto done;
         }
     }
 
diff --git a/src/monitor/monitor_netlink.c b/src/monitor/monitor_netlink.c
index 2fe380ac9..3842c4f16 100644
--- a/src/monitor/monitor_netlink.c
+++ b/src/monitor/monitor_netlink.c
@@ -153,19 +153,17 @@ static bool has_ethernet_encapsulation(const char *sysfs_path)
     }
 
     memset(buf, 0, BUFSIZE);
-    while ((ret = read(fd, buf, BUFSIZE)) != 0) {
-        if (ret == -1) {
-            ret = errno;
-            if (ret == EINTR || ret == EAGAIN) {
-                continue;
-            }
-            DEBUG(SSSDBG_OP_FAILURE,
-                  ("read failed [%d][%s].\n", ret, strerror(ret)));
-            close(fd);
-            return false;
-        }
+    errno = 0;
+    ret = sss_atomic_read_s(fd, buf, BUFSIZE);
+    if (ret == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_OP_FAILURE,
+              ("read failed [%d][%s].\n", ret, strerror(ret)));
+        close(fd);
+        return false;
     }
     close(fd);
+    buf[BUFSIZE-1] = '\0';
 
     return strncmp(buf, "1\n", BUFSIZE) == 0;
 }
diff --git a/src/providers/krb5/krb5_child.c b/src/providers/krb5/krb5_child.c
index 209643a09..cc29c00f6 100644
--- a/src/providers/krb5/krb5_child.c
+++ b/src/providers/krb5/krb5_child.c
@@ -461,18 +461,20 @@ static errno_t sendresponse(int fd, krb5_error_code kerr, int pam_status,
         return ENOMEM;
     }
 
-    written = 0;
-    while (written < resp->size) {
-        ret = write(fd, resp->buf + written, resp->size - written);
-        if (ret == -1) {
-            if (errno == EAGAIN || errno == EINTR) {
-                continue;
-            }
-            ret = errno;
-            DEBUG(1, ("write failed [%d][%s].\n", ret, strerror(ret)));
-            return ret;
-        }
-        written += ret;
+    errno = 0;
+    written = sss_atomic_write_s(fd, resp->buf, resp->size);
+    if (written == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("write failed [%d][%s].\n", ret, strerror(ret)));
+        return ret;
+    }
+
+    if (written != resp->size) {
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("Write error, wrote [%d] bytes, expected [%d]\n",
+               written, resp->size));
+        return EOK;
     }
 
     return EOK;
@@ -1631,25 +1633,14 @@ int main(int argc, const char *argv[])
         goto fail;
     }
 
-    while ((ret = read(STDIN_FILENO, buf + len, IN_BUF_SIZE - len)) != 0) {
-        if (ret == -1) {
-            if (errno == EINTR || errno == EAGAIN) {
-                continue;
-            }
-            DEBUG(1, ("read failed [%d][%s].\n", errno, strerror(errno)));
-            goto fail;
-        } else if (ret > 0) {
-            len += ret;
-            if (len > IN_BUF_SIZE) {
-                DEBUG(1, ("read too much, this should never happen.\n"));
-                goto fail;
-            }
-            continue;
-        } else {
-            DEBUG(1, ("unexpected return code of read [%d].\n", ret));
-            goto fail;
-        }
+    errno = 0;
+    len = sss_atomic_read_s(STDIN_FILENO, buf, IN_BUF_SIZE);
+    if (len == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE, ("read failed [%d][%s].\n", ret, strerror(ret)));
+        goto fail;
     }
+
     close(STDIN_FILENO);
 
     kr = talloc_zero(pd, struct krb5_req);
diff --git a/src/providers/krb5/krb5_common.c b/src/providers/krb5/krb5_common.c
index d33900f18..022745d61 100644
--- a/src/providers/krb5/krb5_common.c
+++ b/src/providers/krb5/krb5_common.c
@@ -321,25 +321,19 @@ errno_t write_krb5info_file(const char *realm, const char *server,
         goto done;
     }
 
-    written = 0;
-    while (written < server_len) {
-        ret = write(fd, server+written, server_len-written);
-        if (ret == -1) {
-            if (errno == EINTR || errno == EAGAIN) {
-                continue;
-            }
-            ret = errno;
-            DEBUG(1, ("write failed [%d][%s].\n", ret, strerror(ret)));
-            goto done;
-        }
-        else {
-            written += ret;
-        }
+    errno = 0;
+    written = sss_atomic_write_s(fd, discard_const(server), server_len);
+    if (written == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("write failed [%d][%s].\n", ret, strerror(ret)));
+        goto done;
     }
 
     if (written != server_len) {
-        DEBUG(1, ("Write error, wrote [%d] bytes, expected [%d]\n",
-                   written, server_len));
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("Write error, wrote [%d] bytes, expected [%d]\n",
+               written, server_len));
         ret = EIO;
         goto done;
     }
diff --git a/src/providers/ldap/ldap_child.c b/src/providers/ldap/ldap_child.c
index e66406c0e..5356f8834 100644
--- a/src/providers/ldap/ldap_child.c
+++ b/src/providers/ldap/ldap_child.c
@@ -446,25 +446,14 @@ int main(int argc, const char *argv[])
         goto fail;
     }
 
-    while ((ret = read(STDIN_FILENO, buf + len, IN_BUF_SIZE - len)) != 0) {
-        if (ret == -1) {
-            if (errno == EINTR || errno == EAGAIN) {
-                continue;
-            }
-            DEBUG(1, ("read failed [%d][%s].\n", errno, strerror(errno)));
-            goto fail;
-        } else if (ret > 0) {
-            len += ret;
-            if (len > IN_BUF_SIZE) {
-                DEBUG(1, ("read too much, this should never happen.\n"));
-                goto fail;
-            }
-            continue;
-        } else {
-            DEBUG(1, ("unexpected return code of read [%d].\n", ret));
-            goto fail;
-        }
+    errno = 0;
+    len = sss_atomic_read_s(STDIN_FILENO, buf, IN_BUF_SIZE);
+    if (len == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE, ("read failed [%d][%s].\n", ret, strerror(ret)));
+        goto fail;
     }
+
     close(STDIN_FILENO);
 
     ret = unpack_buffer(buf, len, ibuf);
@@ -484,22 +473,22 @@ int main(int argc, const char *argv[])
 
     ret = prepare_response(main_ctx, ccname, expire_time, kerr, &resp);
     if (ret != EOK) {
-        DEBUG(1, ("prepare_response failed. [%d][%s].\n", ret, strerror(ret)));
-        return ENOMEM;
+        DEBUG(SSSDBG_CRIT_FAILURE, ("prepare_response failed. [%d][%s].\n", ret, strerror(ret)));
+        goto fail;
     }
 
-    written = 0;
-    while (written < resp->size) {
-        ret = write(STDOUT_FILENO, resp->buf + written, resp->size - written);
-        if (ret == -1) {
-            if (errno == EAGAIN || errno == EINTR) {
-                continue;
-            }
-            ret = errno;
-            DEBUG(1, ("write failed [%d][%s].\n", ret, strerror(ret)));
-            return ret;
-        }
-        written += ret;
+    errno = 0;
+    written = sss_atomic_write_s(STDOUT_FILENO, resp->buf, resp->size);
+    if (written == -1) {
+        ret = errno;
+        DEBUG(SSSDBG_CRIT_FAILURE, ("write failed [%d][%s].\n", ret, strerror(ret)));
+        goto fail;
+    }
+
+    if (written != resp->size) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Expected to write %d bytes, wrote %d\n",
+              resp->size, written));
+        goto fail;
     }
 
     close(STDOUT_FILENO);
diff --git a/src/responder/nss/nsssrv_mmap_cache.c b/src/responder/nss/nsssrv_mmap_cache.c
index 7a7a498b9..e60d06198 100644
--- a/src/responder/nss/nsssrv_mmap_cache.c
+++ b/src/responder/nss/nsssrv_mmap_cache.c
@@ -512,16 +512,16 @@ static errno_t sss_mc_set_recycled(int fd)
         /* What do we do now ? */
         return errno;
     }
-    pos = 0;
-    while (pos < sizeof(h.status)) {
-        ret = write(fd, ((uint8_t *)&w) + pos, sizeof(h.status) - pos);
-        if (ret == -1) {
-            if (errno != EINTR) {
-                return errno;
-            }
-            continue;
-        }
-        pos += ret;
+
+    errno = 0;
+    ret = sss_atomic_write_s(fd, (uint8_t *)&w, sizeof(h.status));
+    if (ret == -1) {
+        return errno;
+    }
+
+    if (ret != sizeof(h.status)) {
+        /* Write error */
+        return EIO;
     }
 
     return EOK;
diff --git a/src/responder/ssh/sshsrv_cmd.c b/src/responder/ssh/sshsrv_cmd.c
index 4882bacf9..149137070 100644
--- a/src/responder/ssh/sshsrv_cmd.c
+++ b/src/responder/ssh/sshsrv_cmd.c
@@ -516,7 +516,7 @@ ssh_host_pubkeys_update_known_hosts(struct ssh_cmd_ctx *cmd_ctx)
                     goto done;
                 }
 
-                wret = sss_atomic_write(fd, line, strlen(line));
+                wret = sss_atomic_write_s(fd, line, strlen(line));
                 if (wret == -1) {
                     ret = errno;
                     goto done;
diff --git a/src/sss_client/pam_sss.c b/src/sss_client/pam_sss.c
index 8778fe19e..3de810c58 100644
--- a/src/sss_client/pam_sss.c
+++ b/src/sss_client/pam_sss.c
@@ -47,6 +47,7 @@
 #include "sss_pam_macros.h"
 
 #include "sss_cli.h"
+#include "util/atomic_io.h"
 
 #include <libintl.h>
 #define _(STRING) dgettext (PACKAGE, STRING)
@@ -499,17 +500,12 @@ static errno_t display_pw_reset_message(pam_handle_t *pamh,
         goto done;
     }
 
-
-    total_len = 0;
-    while (total_len < stat_buf.st_size) {
-        ret = read(fd, msg_buf + total_len, stat_buf.st_size - total_len);
-        if (ret == -1) {
-            if (errno == EINTR || errno == EAGAIN) continue;
-            ret = errno;
-            D(("read failed [%d][%s].", ret, strerror(ret)));
-            goto done;
-        }
-        total_len += ret;
+    errno = 0;
+    total_len = sss_atomic_read_s(fd, msg_buf, stat_buf.st_size);
+    if (ret == -1) {
+        ret = errno;
+        D(("read failed [%d][%s].", ret, strerror(ret)));
+        goto done;
     }
 
     ret = close(fd);
@@ -1088,7 +1084,8 @@ static int send_and_receive(pam_handle_t *pamh, struct pam_items *pi,
 #ifdef HAVE_SELINUX
     char *path = NULL;
     char *tmp_path = NULL;
-    int pos, len;
+    ssize_t written;
+    int len;
     int fd;
     mode_t oldmask;
 #endif /* HAVE_SELINUX */
@@ -1206,21 +1203,24 @@ static int send_and_receive(pam_handle_t *pamh, struct pam_items *pi,
                 goto done;
             }
 
-            pos = 0;
             len = strlen(pi->selinux_user);
-            while (pos < len) {
-                ret = write(fd, pi->selinux_user + pos, len-pos);
-                if (ret < 0) {
-                    if (errno != EINTR) {
-                        logger(pamh, LOG_ERR, "writing to SELinux data file "
-                               "failed. %s", tmp_path);
-                        pam_status = PAM_SYSTEM_ERR;
-                        goto done;
-                    }
-                    continue;
-                }
-                pos += ret;
+
+            errno = 0;
+            written = sss_atomic_write_s(fd, pi->selinux_user, len);
+            if (written == -1) {
+                ret = errno;
+                logger(pamh, LOG_ERR, "writing to SELinux data file "
+                        "failed. %s", tmp_path);
+                pam_status = PAM_SYSTEM_ERR;
+                goto done;
             }
+
+            if (written != len) {
+                logger(pamh, LOG_ERR, "Expected to write %d bytes, wrote %d",
+                       written, len);
+                goto done;
+            }
+
             close(fd);
 
             rename(tmp_path, path);
diff --git a/src/sss_client/ssh/sss_ssh_knownhostsproxy.c b/src/sss_client/ssh/sss_ssh_knownhostsproxy.c
index 6424d7b7c..e45ef45f1 100644
--- a/src/sss_client/ssh/sss_ssh_knownhostsproxy.c
+++ b/src/sss_client/ssh/sss_ssh_knownhostsproxy.c
@@ -140,11 +140,11 @@ connect_socket(int family, struct sockaddr *addr, size_t addr_len)
                 }
 
                 errno = 0;
-                res = sss_atomic_write(i == 0 ? sock : 1, buffer, res);
+                res = sss_atomic_write_s(i == 0 ? sock : 1, buffer, res);
                 ret = errno;
                 if (res == -1) {
                     DEBUG(SSSDBG_OP_FAILURE,
-                          ("sss_atomic_write() failed (%d): %s\n",
+                          ("sss_atomic_write_s() failed (%d): %s\n",
                            ret, strerror(ret)));
                     goto done;
                 } else if (ret == EPIPE) {
diff --git a/src/tools/files.c b/src/tools/files.c
index 694753549..d80e3bd9a 100644
--- a/src/tools/files.c
+++ b/src/tools/files.c
@@ -411,7 +411,7 @@ static int copy_file(const char *src,
     int ifd = -1;
     int ofd = -1;
     char buf[1024];
-    ssize_t cnt, written, res;
+    ssize_t cnt, written;
     struct stat fstatbuf;
 
     ifd = open(src, O_RDONLY);
@@ -463,41 +463,28 @@ static int copy_file(const char *src,
         goto fail;
     }
 
-    while ((cnt = read(ifd, buf, sizeof(buf))) != 0) {
+    while ((cnt = sss_atomic_read_s(ifd, buf, sizeof(buf))) != 0) {
         if (cnt == -1) {
-            if (errno == EINTR || errno == EAGAIN) {
-                continue;
-            }
-
-            DEBUG(1, ("Cannot read() from source file '%s': [%d][%s].\n",
-                        src, ret, strerror(ret)));
+            ret = errno;
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  ("Cannot read() from source file '%s': [%d][%s].\n",
+                   src, ret, strerror(ret)));
             goto fail;
         }
-        else if (cnt > 0) {
-            /* Copy the buffer to the new file */
-            written = 0;
-            while (written < cnt) {
-                res = write(ofd, buf+written, (size_t)cnt-written);
-                if (res == -1) {
-                    ret = errno;
-                    if (ret == EINTR || ret == EAGAIN) {
-                        /* retry the write */
-                        continue;
-                    }
-                    DEBUG(1, ("Cannot write() to destination file '%s': [%d][%s].\n",
-                                dst, ret, strerror(ret)));
-                    goto fail;
-                }
-                else if (res <= 0) {
-                    DEBUG(1, ("Unexpected result from write(): [%d]\n", res));
-                    goto fail;
-                }
-
-                written += res;
-            }
+
+        errno = 0;
+        written = sss_atomic_write_s(ofd, buf, cnt);
+        if (written == -1) {
+            ret = errno;
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  ("Cannot write() to destination file '%s': [%d][%s].\n",
+                   dst, ret, strerror(ret)));
+            goto fail;
         }
-        else {
-            DEBUG(1, ("Unexpected return code of read [%d]\n", cnt));
+
+        if (written != cnt) {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  ("Wrote %d bytes, expected %d\n", written, cnt));
             goto fail;
         }
     }
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);