gfapi: 'glfs_h_creat_open' - new API to create handle and open fd

Right now we have two separate APIs, one
- 'glfs_h_creat_handle' to create handle & another
- 'glfs_h_open' to create a glfd to return to application

Having two separate routines can result in access errors
while trying to create and write into a read-only file.

Since a fd is opened even during file/directory creation,
introducing a new API to make these two operations atomic i.e,
which can create both handle & fd and pass them to application

This is backport of below mainline patch -
- https://review.gluster.org/#/c/glusterfs/+/23448/
- bz#1753569

release-6:
- https://review.gluster.org/#/c/glusterfs/+/23491/

Change-Id: Ibf513fcfcdad175f4d7eb6fa7a61b8feec6d33b5
fixes: bz#1756002
Signed-off-by: Soumya Koduri <skoduri@redhat.com>

2 files changed, 145 insertions, 0 deletions

diff --git a/tests/basic/gfapi/glfs_h_creat_open.c b/tests/basic/gfapi/glfs_h_creat_open.c
new file mode 100644
index 00000000000..7672561e73f
--- /dev/null
+++ b/tests/basic/gfapi/glfs_h_creat_open.c
@@ -0,0 +1,118 @@
+#include <fcntl.h>
+#include <unistd.h>
+#include <time.h>
+#include <limits.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <glusterfs/api/glfs.h>
+#include <glusterfs/api/glfs-handles.h>
+
+#define LOG_ERR(func, ret)                                                     \
+    do {                                                                       \
+        if (ret != 0) {                                                        \
+            fprintf(stderr, "%s : returned error ret(%d), errno(%d)\n", func,  \
+                    ret, errno);                                               \
+            exit(1);                                                           \
+        } else {                                                               \
+            fprintf(stderr, "%s : returned %d\n", func, ret);                  \
+        }                                                                      \
+    } while (0)
+#define LOG_IF_NO_ERR(func, ret)                                               \
+    do {                                                                       \
+        if (ret == 0) {                                                        \
+            fprintf(stderr, "%s : hasn't returned error %d\n", func, ret);     \
+            exit(1);                                                           \
+        } else {                                                               \
+            fprintf(stderr, "%s : returned %d\n", func, ret);                  \
+        }                                                                      \
+    } while (0)
+int
+main(int argc, char *argv[])
+{
+    glfs_t *fs = NULL;
+    int ret = 0;
+    struct glfs_object *root = NULL, *leaf = NULL;
+    glfs_fd_t *fd = NULL;
+    char *filename = "/ro-file";
+    struct stat sb = {
+        0,
+    };
+    char *logfile = NULL;
+    char *volname = NULL;
+    char *hostname = NULL;
+    char buf[32] = "abcdefghijklmnopqrstuvwxyz012345";
+
+    fprintf(stderr, "Starting glfs_h_creat_open\n");
+
+    if (argc != 4) {
+        fprintf(stderr, "Invalid argument\n");
+        exit(1);
+    }
+
+    hostname = argv[1];
+    volname = argv[2];
+    logfile = argv[3];
+
+    fs = glfs_new(volname);
+    if (!fs) {
+        fprintf(stderr, "glfs_new: returned NULL\n");
+        return 1;
+    }
+
+    ret = glfs_set_volfile_server(fs, "tcp", hostname, 24007);
+    LOG_ERR("glfs_set_volfile_server", ret);
+
+    ret = glfs_set_logging(fs, logfile, 7);
+    LOG_ERR("glfs_set_logging", ret);
+
+    ret = glfs_init(fs);
+    LOG_ERR("glfs_init", ret);
+
+    sleep(2);
+    root = glfs_h_lookupat(fs, NULL, "/", &sb, 0);
+    if (!root) {
+        ret = -1;
+        LOG_ERR("glfs_h_lookupat root", ret);
+    }
+    leaf = glfs_h_lookupat(fs, root, filename, &sb, 0);
+    if (!leaf) {
+        ret = -1;
+        LOG_IF_NO_ERR("glfs_h_lookupat leaf", ret);
+    }
+
+    leaf = glfs_h_creat_open(fs, root, filename, O_RDONLY, 00444, &sb, &fd);
+    if (!leaf || !fd) {
+        ret = -1;
+        LOG_ERR("glfs_h_creat leaf", ret);
+    }
+    fprintf(stderr, "glfs_h_create_open leaf - %p\n", leaf);
+
+    ret = glfs_write(fd, buf, 32, 0);
+    if (ret < 0) {
+        fprintf(stderr, "glfs_write: error writing to file %s, %s\n", filename,
+                strerror(errno));
+        goto out;
+    }
+
+    ret = glfs_h_getattrs(fs, leaf, &sb);
+    LOG_ERR("glfs_h_getattrs", ret);
+
+    if (sb.st_size != 32) {
+        fprintf(stderr, "glfs_write: post size mismatch\n");
+        goto out;
+    }
+
+    fprintf(stderr, "Successfully opened and written to a read-only file \n");
+out:
+    if (fd)
+        glfs_close(fd);
+
+    ret = glfs_fini(fs);
+    LOG_ERR("glfs_fini", ret);
+
+    fprintf(stderr, "End of libgfapi_fini\n");
+
+    exit(0);
+}
diff --git a/tests/basic/gfapi/glfs_h_creat_open.t b/tests/basic/gfapi/glfs_h_creat_open.t
new file mode 100755
index 00000000000..f24ae7395be
--- /dev/null
+++ b/tests/basic/gfapi/glfs_h_creat_open.t
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup;
+
+TEST glusterd
+
+TEST $CLI volume create $V0 $H0:$B0/brick1;
+EXPECT 'Created' volinfo_field $V0 'Status';
+
+TEST $CLI volume start $V0;
+EXPECT 'Started' volinfo_field $V0 'Status';
+
+logdir=`gluster --print-logdir`
+
+TEST build_tester $(dirname $0)/glfs_h_creat_open.c -lgfapi
+
+TEST ./$(dirname $0)/glfs_h_creat_open $H0 $V0  $logdir/glfs.log
+
+cleanup_tester $(dirname $0)/glfs_h_creat_open
+
+TEST $CLI volume stop $V0
+TEST $CLI volume delete $V0
+
+cleanup;