[core] fdlog.[ch]; fdevent_*_logger_* -> fdlog_*

code move and rename fdevent_*_logger_*() to fdlog_*()

1 files changed, 203 insertions, 0 deletions

diff --git a/src/fdlog.c b/src/fdlog.c
new file mode 100644
index 00000000..f6fd0766
--- /dev/null
+++ b/src/fdlog.c
@@ -0,0 +1,203 @@
+#include "first.h"
+
+#include "fdlog.h"
+
+#include <sys/types.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "fdevent.h"
+#include "log.h"
+
+typedef struct fdlog_pipe {
+    pid_t pid;
+    int fds[2];
+    const char *cmd;
+    unix_time64_t start;
+} fdlog_pipe;
+
+struct fdlog_pipes_t {
+    fdlog_pipe *ptr;
+    uint32_t used;
+    uint32_t size;
+};
+
+static struct fdlog_pipes_t fdlog_pipes;
+
+
+static pid_t
+fdlog_pipe_spawn (const char * const fn, const int rfd)
+{
+    char *args[4];
+    int devnull = fdevent_open_devnull();
+    pid_t pid;
+
+    if (-1 == devnull) {
+        return -1;
+    }
+
+    *(const char **)&args[0] = "/bin/sh";
+    *(const char **)&args[1] = "-c";
+    *(const char **)&args[2] = fn;
+    args[3] = NULL;
+
+    pid = fdevent_fork_execve(args[0], args, NULL, rfd, devnull, devnull, -1);
+
+    if (pid > 0) {
+        close(devnull);
+    }
+    else {
+        int errnum = errno;
+        close(devnull);
+        errno = errnum;
+    }
+    return pid;
+}
+
+
+__attribute_noinline__
+static int
+fdlog_pipe_restart (fdlog_pipe * const fdp, const unix_time64_t ts)
+{
+    if (fdp->start + 5 < ts) { /* limit restart to once every 5 sec */
+        /* restart child process using existing pipe fds */
+        fdp->start = ts;
+        fdp->pid = fdlog_pipe_spawn(fdp->cmd, fdp->fds[0]);
+    }
+    return (fdp->pid > 0) ? 1 : -1;
+}
+
+
+void
+fdlog_pipes_restart (const unix_time64_t ts)
+{
+    for (uint32_t i = 0; i < fdlog_pipes.used; ++i) {
+        fdlog_pipe * const fdp = fdlog_pipes.ptr+i;
+        if (fdp->pid > 0) continue;
+        fdlog_pipe_restart(fdp, ts);
+    }
+}
+
+
+int
+fdlog_pipes_waitpid_cb (const pid_t pid)
+{
+    for (uint32_t i = 0; i < fdlog_pipes.used; ++i) {
+        fdlog_pipe * const fdp = fdlog_pipes.ptr+i;
+        if (fdp->pid != pid) continue;
+
+        fdp->pid = -1;
+        return fdlog_pipe_restart(fdp, log_monotonic_secs);
+    }
+    return 0;
+}
+
+
+void
+fdlog_pipes_close (void)
+{
+    for (uint32_t i = 0; i < fdlog_pipes.used; ++i) {
+        fdlog_pipe * const fdp = fdlog_pipes.ptr+i;
+        close(fdp->fds[0]);
+        if (fdp->fds[1] != STDERR_FILENO) close(fdp->fds[1]);
+    }
+    free(fdlog_pipes.ptr);
+    fdlog_pipes.ptr = NULL;
+    fdlog_pipes.used = 0;
+    fdlog_pipes.size = 0;
+}
+
+
+void
+fdlog_pipes_abandon_pids (void)
+{
+    for (uint32_t i = 0; i < fdlog_pipes.used; ++i) {
+        fdlog_pipe * const fdp = fdlog_pipes.ptr+i;
+        fdp->pid = -1;
+    }
+}
+
+
+void
+fdlog_pipe_serrh (const int fd)
+{
+    for (uint32_t i = 0; i < fdlog_pipes.used; ++i) {
+        fdlog_pipe * const fdp = fdlog_pipes.ptr+i;
+        if (fdp->fds[1] != fd) continue;
+
+        fdp->fds[1] = STDERR_FILENO;
+        break;
+    }
+}
+
+
+static void
+fdlog_pipe_init (const char * const cmd, const int fds[2], const pid_t pid)
+{
+    if (fdlog_pipes.used == fdlog_pipes.size) {
+        fdlog_pipes.size += 4;
+        fdlog_pipes.ptr =
+          realloc(fdlog_pipes.ptr, fdlog_pipes.size * sizeof(fdlog_pipe));
+        force_assert(fdlog_pipes.ptr);
+    }
+    fdlog_pipe * const fdp = fdlog_pipes.ptr + fdlog_pipes.used++;
+    fdp->cmd = cmd; /* note: cmd must persist in memory (or else copy here) */
+    fdp->fds[0] = fds[0];
+    fdp->fds[1] = fds[1];
+    fdp->pid = pid;
+    fdp->start = log_monotonic_secs;
+}
+
+
+static int
+fdlog_pipe_open (const char * const fn)
+{
+    int fds[2];
+    if (pipe(fds))
+        return -1;
+    fdevent_setfd_cloexec(fds[0]);
+    fdevent_setfd_cloexec(fds[1]);
+
+    pid_t pid = fdlog_pipe_spawn(fn, fds[0]);
+    if (pid > 0) {
+        /*(nonblocking write() from lighttpd)*/
+        if (0 != fdevent_fcntl_set_nb(fds[1])) { /*(ignore)*/ }
+        fdlog_pipe_init(fn, fds, pid);
+        return fds[1];
+    }
+    else {
+        int errnum = errno;
+        close(fds[0]);
+        close(fds[1]);
+        errno = errnum;
+        return -1;
+    }
+}
+
+
+int
+fdlog_open (const char * const fn)
+{
+    if (fn[0] != '|') { /*(permit symlinks)*/
+        int flags = O_APPEND | O_WRONLY | O_CREAT;
+        return fdevent_open_cloexec(fn, 1, flags, 0644);
+    }
+    else {
+        return fdlog_pipe_open(fn+1); /*(skip the '|')*/
+    }
+}
+
+
+int
+fdlog_cycle (const char * const fn, int * const curfd)
+{
+    if (fn[0] != '|') {
+        int fd = fdlog_open(fn);
+        if (-1 == fd) return -1; /*(error; leave *curfd as-is)*/
+        if (-1 != *curfd) close(*curfd);
+        *curfd = fd;
+    }
+    return *curfd;
+}