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#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
int
main(int argc, char *argv[])
{
int fd = -1, ret = -1, len = 0;
char *path = NULL,
buf[128] =
{
0,
},
*cmd = NULL;
struct stat stbuf = {
0,
};
int write_to_child[2] =
{
0,
},
write_to_parent[2] = {
0,
};
path = argv[1];
cmd = argv[2];
assert(argc == 3);
ret = pipe(write_to_child);
if (ret < 0) {
fprintf(stderr,
"creation of write-to-child pipe failed "
"(%s)\n",
strerror(errno));
goto out;
}
ret = pipe(write_to_parent);
if (ret < 0) {
fprintf(stderr,
"creation of write-to-parent pipe failed "
"(%s)\n",
strerror(errno));
goto out;
}
ret = fork();
switch (ret) {
case 0:
close(write_to_child[1]);
close(write_to_parent[0]);
/* child, wait for instructions to execute command */
ret = read(write_to_child[0], buf, 128);
if (ret < 0) {
fprintf(stderr, "child: read on pipe failed (%s)\n",
strerror(errno));
goto out;
}
system(cmd);
ret = write(write_to_parent[1], "1", 2);
if (ret < 0) {
fprintf(stderr, "child: write to pipe failed (%s)\n",
strerror(errno));
goto out;
}
break;
case -1:
fprintf(stderr, "fork failed (%s)\n", strerror(errno));
goto out;
default:
close(write_to_parent[1]);
close(write_to_child[0]);
fd = open(path, O_CREAT | O_RDWR | O_APPEND, S_IRWXU);
if (fd < 0) {
fprintf(stderr, "open failed (%s)\n", strerror(errno));
goto out;
}
len = strlen("test-content") + 1;
ret = write(fd, "test-content", len);
if (ret < len) {
fprintf(stderr, "write failed %d (%s)\n", ret, strerror(errno));
}
ret = pread(fd, buf, 128, 0);
if ((ret == len) && (strcmp(buf, "test-content") == 0)) {
fprintf(stderr,
"read should've failed as previous "
"write would've failed with EDQUOT, but its "
"successful");
ret = -1;
goto out;
}
ret = write(write_to_child[1], "1", 2);
if (ret < 0) {
fprintf(stderr, "parent: write to pipe failed (%s)\n",
strerror(errno));
goto out;
}
ret = read(write_to_parent[0], buf, 128);
if (ret < 0) {
fprintf(stderr, "parent: read from pipe failed (%s)\n",
strerror(errno));
goto out;
}
/* this will force a sync on cached-write and now that quota
limit is increased, sync will be successful. ignore return
value as fstat would fail with EDQUOT (picked up from
cached-write because of previous sync failure.
*/
fstat(fd, &stbuf);
ret = pread(fd, buf, 128, 0);
if (ret != len) {
fprintf(stderr,
"post cmd read failed %d (data:%s) "
"(error:%s)\n",
ret, buf, strerror(errno));
goto out;
}
if (strcmp(buf, "test-content")) {
fprintf(stderr, "wrong data (%s)\n", buf);
goto out;
}
}
ret = 0;
out:
return ret;
}
|
