afm-launch: refactoring launch

The children process have now the same parent
that is the daemon.

Change-Id: Id09ec2e52e90873ea2993b4c7f631b53a4cb5520
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

diff --git a/src/afm-launch.c b/src/afm-launch.c
index 75bd4b0..49172f6 100644 (file)
--- a/src/afm-launch.c
+++ b/src/afm-launch.c
@@ -28,6 +28,8 @@
 #include <assert.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <poll.h>
+#include <signal.h>
 
 extern char **environ;
 
@@ -61,8 +63,7 @@ struct launchparam {
        char **uri;
        const char *secret;
        const char *datadir;
-       struct exec_vector *master;
-       struct exec_vector *slave;
+       struct exec_vector *execs;
 };
 
 struct confread {
@@ -78,7 +79,9 @@ struct desc_list *launchers = NULL;
 
 static gid_t groupid = 0;
 
-const char separators[] = " \t\n";
+static const char separators[] = " \t\n";
+static const char readystr[] = "READY=1";
+static const int ready_timeout = 1500;
 
 static void dump_launchers()
 {
@@ -516,153 +519,71 @@ static union arguments instantiate_arguments(
        }
 }
 
-static void mksecret(char buffer[9])
-{
-       snprintf(buffer, 9, "%08lX", (0xffffffff & random()));
-}
-
-static int mkport()
-{
-       static int port_ring = 12345;
-       int port = port_ring;
-       if (port < 12345 || port > 15432)
-               port = 12345;
-       port_ring = port + 1;
-       return port;
-}
-
-static int launch_local_1(
+static pid_t launch(
        struct afm_launch_desc *desc,
-       pid_t                   children[2],
-       struct launchparam     *params
-)
-{
-       int rc;
-       char **args;
-
-       /* fork the master child */
-       children[0] = fork();
-       if (children[0] < 0) {
-               ERROR("master fork failed: %m");
-               return -1;
-       }
-       if (children[0]) {
-               /********* in the parent process ************/
-               return 0;
-       }
-
-       /********* in the master child ************/
-
-       /* avoid set-gid effect */
-       setresgid(groupid, groupid, groupid);
-
-       /* enter the process group */
-       rc = setpgid(0, 0);
-       if (rc) {
-               ERROR("setpgid failed");
-               _exit(1);
-       }
-
-       /* enter security mode */
-       rc = secmgr_prepare_exec(desc->tag);
-       if (rc < 0) {
-               ERROR("call to secmgr_prepare_exec failed: %m");
-               _exit(1);
-       }
-
-       /* enter the datadirectory */
-       rc = mkdir(params->datadir, 0755);
-       if (rc && errno != EEXIST) {
-               ERROR("creation of datadir %s failed: %m", params->datadir);
-               _exit(1);
-       }
-       rc = chdir(params->datadir);
-       if (rc) {
-               ERROR("can't enter the datadir %s: %m", params->datadir);
-               _exit(1);
-       }
-
-       args = instantiate_arguments(params->master->args, desc, params, 1).vector;
-       if (args == NULL) {
-               ERROR("out of memory in master");
-       }
-       else {
-               rc = execve(args[0], args, environ);
-               ERROR("failed to exec master %s: %m", args[0]);
-       }
-       _exit(1);
-}
-
-static int launch_local_2(
-       struct afm_launch_desc *desc,
-       pid_t                   children[2],
-       struct launchparam     *params
+       struct launchparam     *params,
+       struct exec_vector     *exec,
+       pid_t                   progrp
 )
 {
        int rc;
-       char message[10];
-       int mpipe[2];
-       int spipe[2];
        char **args;
+       pid_t pid;
+       int rpipe[2];
+       struct pollfd pfd;
 
        /* prepare the pipes */
-       rc = pipe2(mpipe, O_CLOEXEC);
+       rc = pipe(rpipe);
        if (rc < 0) {
                ERROR("error while calling pipe2: %m");
                return -1;
        }
-       rc = pipe2(spipe, O_CLOEXEC);
-       if (rc < 0) {
-               ERROR("error while calling pipe2: %m");
-               close(spipe[0]);
-               close(spipe[1]);
+
+       /* instanciate the arguments */
+       params->readyfd = rpipe[1];
+       args = instantiate_arguments(exec->args, desc, params, 1).vector;
+       if (args == NULL) {
+               close(rpipe[0]);
+               close(rpipe[1]);
+               ERROR("out of memory in master");
+               errno = ENOMEM;
                return -1;
        }
 
        /* fork the master child */
-       children[0] = fork();
-       if (children[0] < 0) {
+       pid = fork();
+       if (pid < 0) {
+
+               /********* can't fork ************/
+
+               close(rpipe[0]);
+               close(rpipe[1]);
+               free(args);
                ERROR("master fork failed: %m");
-               close(mpipe[0]);
-               close(mpipe[1]);
-               close(spipe[0]);
-               close(spipe[1]);
                return -1;
        }
-       if (children[0]) {
+       if (pid) {
+
                /********* in the parent process ************/
-               close(mpipe[1]);
-               close(spipe[0]);
-               /* wait the ready signal (that transmit the slave pid) */
-               rc = read(mpipe[0], &children[1], sizeof children[1]);
-               close(mpipe[0]);
-               if (rc  <= 0) {
-                       ERROR("reading master pipe failed: %m");
-                       close(spipe[1]);
-                       return -1;
-               }
-               assert(rc == sizeof children[1]);
-               /* start the child */
-               rc = write(spipe[1], "start", 5);
-               if (rc < 0) {
-                       ERROR("writing slave pipe failed: %m");
-                       close(spipe[1]);
-                       return -1;
-               }
-               assert(rc == 5);
-               close(spipe[1]);
-               return 0;
+
+               close(rpipe[1]);
+               free(args);
+               pfd.fd = rpipe[0];
+               pfd.events = POLLIN;
+               poll(&pfd, 1, ready_timeout);
+               close(rpipe[0]);
+               return pid;
        }
 
-       /********* in the master child ************/
-       close(mpipe[0]);
-       close(spipe[1]);
+       /********* in the child process ************/
+
+       close(rpipe[0]);
 
        /* avoid set-gid effect */
        setresgid(groupid, groupid, groupid);
 
        /* enter the process group */
-       rc = setpgid(0, 0);
+       rc = setpgid(0, progrp);
        if (rc) {
                ERROR("setpgid failed");
                _exit(1);
@@ -687,50 +608,17 @@ static int launch_local_2(
                _exit(1);
        }
 
-       /* fork the slave child */
-       children[1] = fork();
-       if (children[1] < 0) {
-               ERROR("slave fork failed: %m");
-               _exit(1);
-       }
-       if (children[1] == 0) {
-               /********* in the slave child ************/
-               close(mpipe[0]);
-               rc = read(spipe[0], message, sizeof message);
-               if (rc <= 0) {
-                       ERROR("reading slave pipe failed: %m");
-                       _exit(1);
-               }
-
-               args = instantiate_arguments(params->slave->args, desc, params, 1).vector;
-               if (args == NULL) {
-                       ERROR("out of memory in slave");
-               }
-               else {
-                       rc = execve(args[0], args, environ);
-                       ERROR("failed to exec slave %s: %m", args[0]);
-               }
-               _exit(1);
+       /* signal if needed */
+       if (!exec->has_readyfd) {
+               write(rpipe[1], readystr, sizeof(readystr) - 1);
+               close(rpipe[1]);
        }
 
-       /********* still in the master child ************/
-       close(spipe[1]);
-       args = instantiate_arguments(params->master->args, desc, params, 1).vector;
-       if (args == NULL) {
-               ERROR("out of memory in master");
-       }
-       else {
-               rc = write(mpipe[1], &children[1], sizeof children[1]);
-               if (rc <= 0) {
-                       ERROR("can't write master pipe: %m");
-               }
-               else {
-                       close(mpipe[1]);
-                       rc = execve(args[0], args, environ);
-                       ERROR("failed to exec master %s: %m", args[0]);
-               }
-       }
+       /* executes the process */
+       rc = execve(args[0], args, environ);
+       ERROR("failed to exec master %s: %m", args[0]);
        _exit(1);
+       return -1;
 }
 
 static int launch_local(
@@ -739,9 +627,19 @@ static int launch_local(
        struct launchparam     *params
 )
 {
-       if (params->slave == NULL)
-               return launch_local_1(desc, children, params);
-       return launch_local_2(desc, children, params);
+       children[0] = launch(desc, params, &params->execs[0], 0);
+       if (children[0] <= 0)
+               return -1;
+
+       if (params->execs[1].args == NULL)
+               return 0;
+
+       children[1] = launch(desc, params, &params->execs[1], children[0]);
+       if (children[1] > 0)
+               return 0;
+
+       killpg(children[0], SIGKILL);
+       return -1;
 }
 
 static int launch_remote(
@@ -750,14 +648,13 @@ static int launch_remote(
        struct launchparam     *params
 )
 {
-       int rc;
        char *uri;
 
        /* instanciate the uri */
-       if (params->slave == NULL)
+       if (params->execs[1].args == NULL)
                uri = NULL;
        else
-               uri = instantiate_arguments(params->slave->args, desc, params, 0).scalar;
+               uri = instantiate_arguments(params->execs[1].args, desc, params, 0).scalar;
        if (uri == NULL) {
                ERROR("out of memory for remote uri");
                errno = ENOMEM;
@@ -765,12 +662,29 @@ static int launch_remote(
        }
 
        /* launch the command */
-       rc = launch_local_1(desc, children, params);
-       if (rc)
+       children[0] = launch(desc, params, &params->execs[0], 0);
+       if (children[0] <= 0) {
                free(uri);
-       else
-               *params->uri = uri;
-       return rc;
+               return -1;
+       }
+
+       *params->uri = uri;
+       return 0;
+}
+
+static void mksecret(char buffer[9])
+{
+       snprintf(buffer, 9, "%08lX", (0xffffffff & random()));
+}
+
+static int mkport()
+{
+       static int port_ring = 12345;
+       int port = port_ring;
+       if (port < 12345 || port > 15432)
+               port = 12345;
+       port_ring = port + 1;
+       return port;
 }
 
 static struct desc_list *search_launcher(const char *type, enum afm_launch_mode mode)
@@ -828,8 +742,7 @@ int afm_launch(struct afm_launch_desc *desc, pid_t children[2], char **uri)
        params.port = mkport();
        params.secret = secret;
        params.datadir = datadir;
-       params.master = &dl->execs[0];
-       params.slave = &dl->execs[1];
+       params.execs = dl->execs;
 
        switch (desc->mode) {
        case mode_local:
@@ -854,7 +767,7 @@ int afm_launch_initialize()
                groupid = -1;
 
        rc = read_configuration_file(FWK_LAUNCH_CONF);
-       dump_launchers();
+       /* dump_launchers(); */
        return rc;
 }