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Check-in Number: 1019
Date: 2001-Sep-18 16:38:51 (local)
2001-Sep-18 14:38:51 (UTC)
User:ms
Branch:
Comment: Pipe channel handler redesign, bugfixes, and cleanup.
Tickets:
Inspections:
Files:
ossp-pkg/l2/TODO      1.22 -> 1.23     1 inserted, 0 deleted
ossp-pkg/l2/l2_ch_pipe.c      1.10 -> 1.11     116 inserted, 40 deleted
ossp-pkg/l2/l2_test.c      1.23 -> 1.24     41 inserted, 49 deleted
ossp-pkg/l2/TODO 1.22 -> 1.23 

--- TODO 2001/09/14 13:27:17     1.22
+++ TODO 2001/09/18 14:38:51     1.23
@@ -25,6 +25,7 @@
 
 MS:
 - implement pipe channel
+- review pipe handler for dangling descriptors
 
 ISSUES
 ------

ossp-pkg/l2/l2_ch_pipe.c 1.10 -> 1.11 

--- l2_ch_pipe.c 2001/09/14 15:40:04     1.10
+++ l2_ch_pipe.c 2001/09/18 14:38:51     1.11
@@ -32,24 +32,37 @@
 #include <unistd.h>
 #include <signal.h>
 
+#define L2_PIPE_MODEDIRECT   1 /* direct command execution */
+#define L2_PIPE_MODESHELL    2 /* shell  command execution */
+#define L2_PIPE_MAXARGS    256 /* shell  command execution */
+
 /* declare private channel configuration */
 typedef struct {
-    int iPipe; /* pipe filedescriptor used for writing only */
+    int piFd[2];               /* pipe file descriptor           */
+    int iMode;                 /* execution mode direct or shell */
+    char *szCmdpath;          /* path to command and arguments  */
+    char *pVec[L2_PIPE_MAXARGS]; /* vector of command and params */
 } l2_ch_pipe_t;
 
 static void catchsignal(int sig, ...)
 {
     va_list ap;
-    static l2_context_t *ctx = NULL;
+    static l2_ch_pipe_t *cfg = NULL;
 
     va_start(ap, sig);
     if (sig == 0)
-        ctx = va_arg(ap, l2_context_t *);
+        cfg = va_arg(ap, l2_ch_pipe_t *);
     else if (sig == SIGCHLD) {
-        ((l2_ch_pipe_t *)(int *)ctx->vp)->iPipe = -1; /* TODO: Fill in with new pipe fd */
+        fprintf(stderr, "Pipe: SIGCHLD caught\n");
+        close(cfg->piFd[1]);
+        cfg->piFd[1] = -1; /* TODO: Fill in with new pipe fd */
+    }
+    else if (sig == SIGPIPE) {
+        fprintf(stderr, "Pipe: SIGPIPE caught\n");
+        close(cfg->piFd[1]);
+        cfg->piFd[1] = -1; /* TODO: Fill in with new pipe fd */
+        /* ((l2_ch_pipe_t *)(int *)ctx->vp)->piFd[1] = -1; */
     }
-    else if (sig == SIGPIPE)
-        ((l2_ch_pipe_t *)(int *)ctx->vp)->iPipe = -1;
     va_end(ap);
 }
 
@@ -63,7 +76,11 @@
         return L2_ERR_ARG;
 
     /* initialize configuration with reasonable defaults */
-    cfg->iPipe = -1; 
+    cfg->piFd[0]    = -1; 
+    cfg->piFd[1]    = -1; 
+    cfg->iMode      = -1; 
+    cfg->szCmdpath = NULL;
+    memset(cfg->pVec, 0, sizeof(cfg->pVec));
 
     /* link private channel configuration into channel context */
     ctx->vp = cfg;
@@ -75,45 +92,114 @@
 static l2_result_t hook_configure(l2_context_t *ctx, l2_channel_t *ch, const char *fmt, va_list ap)
 {
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
-    l2_param_t pa[2]; 
+    l2_param_t pa[3]; 
     l2_result_t rv;
+    char szMode[16]; /* just eneough for double-byte "direct" and NULL */
 
     /* feed and call generic parameter parsing engine */
-    L2_PARAM_SET(pa[0], pipe, INT, &cfg->iPipe);
-    L2_PARAM_END(pa[1]);
+    L2_PARAM_SET(pa[0], mode, CHARPTR, szMode);
+    L2_PARAM_SET(pa[1], path, STRING, &cfg->szCmdpath);
+    L2_PARAM_END(pa[2]);
     rv = l2_util_setparams(pa, fmt, ap);
 
-    /* validate the pipe fd */
-    if (cfg->iPipe == -1)
+    if (strcmp(szMode, "direct") == NULL)
+        cfg->iMode = L2_PIPE_MODEDIRECT;
+    else if (strcmp(szMode, "shell") == NULL)
+        cfg->iMode = L2_PIPE_MODESHELL;
+    else
         return L2_ERR_ARG;
 
-    catchsignal(0, ctx); /* initialize signal handler with incoming context */
+    catchsignal(0, cfg); /* initialize signal handler with incoming context */
     signal(SIGCHLD, (void(*)())catchsignal); /* pipe changes descriptor     */
     signal(SIGPIPE, (void(*)())catchsignal); /* pipe closes reading fd      */
 
     return rv;
 }
 
+/**********************************************************
+ * parse_cmdpath: Helper method to hook_open              *
+ *   Parses szBuf into an argv-style string vector szArgs *
+ **********************************************************/
+static l2_result_t parse_cmdpath (char *szBuf, char *szArgs[]) {
+    int iCnt = 0;
+    while ((iCnt++ < L2_PIPE_MAXARGS) && (*szBuf != NULL)) {
+        while ((*szBuf == ' ') || (*szBuf == '\t'))
+            *szBuf++ = '\0';
+        *szArgs++ = szBuf;
+        while ((*szBuf != '\0') && (*szBuf != ' ') && (*szBuf != '\t'))
+            szBuf++;
+    }
+    *szArgs = NULL;
+
+    if (iCnt <= L2_PIPE_MAXARGS)
+        return L2_OK;
+    else
+        return L2_ERR_ARG;
+}
+
+/**********************************************************
+ * child_exec: Helper method to hook_open                 *
+ *   Redirect stdin to read from cfg->piFd. Exec a given  *
+ *   command or passes it to the sh shell for execution.  *
+ **********************************************************/
+static l2_result_t child_exec(l2_ch_pipe_t *cfg)
+{
+    /* make sure a command path was set */
+    if (cfg->szCmdpath == NULL)
+        return L2_ERR_USE;
+
+        close(cfg->piFd[1]);                  /* close the writing end,  */
+        cfg->piFd[1] = -1;                    /* because we don't use it */
+        dup2(cfg->piFd[0], fileno(stdin));    /* copy the reading end    */
+
+        return execvp(*cfg->pVec, cfg->pVec); /* launch                  */
+}
+
+/* open channel */
+static l2_result_t hook_open(l2_context_t *ctx, l2_channel_t *ch)
+{
+    l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
+    l2_result_t rv;
+    pid_t Pid;
+
+    if ((rv = parse_cmdpath(cfg->szCmdpath, cfg->pVec)) != L2_OK)
+        return rv;
+
+    if (pipe(cfg->piFd) == -1)      /* open the pipe  */
+        return L2_ERR_SYS;
+
+    if ((Pid = fork()) > 0) {       /* parent process */
+        close(cfg->piFd[0]);
+        cfg->piFd[0] = -1;
+    }
+    else if ((Pid = fork()) == 0) { /* child process  */
+        /* if child returns, there was an error       */
+        if (child_exec(cfg) == -1) {
+            close(cfg->piFd[0]);
+            cfg->piFd[0] = -1;
+            return L2_ERR_SYS;
+        }
+    }
+    else /* fork failed  */
+        return L2_ERR_SYS;
+
+    return L2_OK;
+}
+
 /* write to channel */
 static l2_result_t hook_write(l2_context_t *ctx, l2_channel_t *ch,
                               l2_level_t level, const char *buf, size_t buf_size)
 {
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
-    l2_channel_t *downstream = l2_channel_downstream(ch);
-    l2_result_t rv;
-    
+
     /* validate the pipe fd */
-    if (cfg->iPipe == -1)
-        return L2_ERR_ARG;
+    if (cfg->piFd[1] == -1)  /* TODO: possibly remove this validation in */
+        return L2_ERR_ARG;   /*       lieu of incoming SIGPIPE signal    */
 
     /* write message to channel pipe */
-    if (write(cfg->iPipe, buf, buf_size) == -1)
+    if (write(cfg->piFd[1], buf, buf_size) == -1)
         return L2_ERR_SYS;
 
-    /* write to downstream channel */
-    if ((rv = l2_channel_write(downstream, level, buf, buf_size)) != L2_OK)
-        return rv;
-
     return L2_OK;
 }
 
@@ -121,16 +207,10 @@
 static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch)
 {
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
-    l2_channel_t *downstream = l2_channel_downstream(ch);
-    l2_result_t rv;
-    
-    /* close channel pipe */
-    close(cfg->iPipe);
-    cfg->iPipe = -1;
 
-    /* close downstream channel, too */
-    if ((rv = l2_channel_close(downstream)) != L2_OK)
-        return rv;
+    /* close channel pipe for parent process created in hook_open() */
+    close(cfg->piFd[1]);
+    cfg->piFd[1] = -1;
 
     return L2_OK;
 }
@@ -139,25 +219,21 @@
 static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
 {
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
-    l2_channel_t *downstream = l2_channel_downstream(ch);
-    l2_result_t rv;
 
     /* destroy channel configuration */
+    free(&cfg->szCmdpath);
+    cfg->szCmdpath = NULL;
     free(cfg);
 
-    /* destroy downstream channel, too */
-    if ((rv = l2_channel_destroy(downstream)) != L2_OK)
-        return rv;
-
     return L2_OK;
 }
 
 /* exported channel handler structure */
 l2_handler_t l2_handler_pipe = {
-    L2_CHANNEL_FILTER,
+    L2_CHANNEL_OUTPUT,
     hook_create,
     hook_configure,
-    NULL,
+    hook_open,
     hook_write,
     NULL,
     hook_close,

ossp-pkg/l2/l2_test.c 1.23 -> 1.24 

--- l2_test.c    2001/09/14 19:11:00     1.23
+++ l2_test.c    2001/09/18 14:38:51     1.24
@@ -34,7 +34,7 @@
 #include <netinet/in.h>
 #include <netdb.h>
 #include <syslog.h>
-#include <unistd.h>
+#include <unistd.h>      /* unistd and fcntl included for pipes */
 #include <fcntl.h>
 
 #include "l2.h"
@@ -74,84 +74,42 @@
 #ifdef WITH_PIPE
     l2_channel_t *chPipe;
 #endif
-#ifdef WITH_SOCKET
     l2_channel_t *chSock;
-#endif
 #ifdef WITH_SMTP
     l2_channel_t *chSmtp;
 #endif
     l2_stream_t *st;
 
-    int pipdesc[2]; /* For use with our pipe channel test */
     /*
      * Typical steps to use a buffered file logging stream
      */
-
     if ((st = l2_stream_create()) == NULL)
         die("failed to create stream");
 
-#ifdef WITH_SOCKET
-    /* Atenzione! Before doing any socket testing, make sure you have a valid */
-    /* end point listening, or else you will only get an error message when   */
-    /* the thing tries to connect.                                            */
-    if ((chSock = l2_channel_create(&l2_handler_socket)) == NULL)
-        die("failed to create socket channel");
-
-    if (l2_channel_configure(chSock, "protocol,ipversion,host,port",\
-        IPPROTO_TCP, AF_INET, "localhost", 2002) != L2_OK)
-        die("failed to configure socket ipv4 channel");
-#if 0
-    if (l2_channel_configure(chSock, "protocol,ipversion,host,port",\
-          IPPROTO_TCP, AF_INET6, "0:0:0:0:0:0:0:1", 2002) != L2_OK)
-          die("failed to configure socket ipv6 channel");
-#endif
-    if (l2_channel_open(chSock) != L2_OK)
-        die("failed to open socket channel");
-
-    if (l2_stream_channel(st, chSock, L2_LEVEL_UPTO(L2_LEVEL_WARNING), L2_LEVEL_NONE) != L2_OK)
-        die("failed to attach first channel into stream");
-#endif
-
     if ((chPrefix  = l2_channel_create(&l2_handler_prefix)) == NULL) /* Prefix */
         die("failed to create prefix channel");
 
     if (l2_channel_configure(chPrefix, "prefix,timezone", "[%d-%m-%Y/%H:%M:%S] %L test[%P]: ", "local") != L2_OK)
         die("failed to configure prefix channel");
 
-    if ((chBuf  = l2_channel_create(&l2_handler_buffer)) == NULL) /* Buffer */
+    if ((chBuf  = l2_channel_create(&l2_handler_buffer)) == NULL)    /* Buffer */
         die("failed to create buffer channel");
 
     if (l2_channel_configure(chBuf, "size", 100) != L2_OK)
         die("failed to configure buffer channel");
 
-    if ((chFile = l2_channel_create(&l2_handler_file)) == NULL)   /* File   */
+    if ((chFile = l2_channel_create(&l2_handler_file)) == NULL)      /* File   */
         die("failed to create file channel");
 
     if (l2_channel_configure(chFile, "path,append,perm", "l2_test.log", TRUE, 0644) != L2_OK)
         die("failed to configure file channel");
 
-#ifdef WITH_PIPE
-    if (pipe(pipdesc))
-        die("pipe() call failed");
-
-    if ((chPipe = l2_channel_create(&l2_handler_pipe)) == NULL)   /* Pipe */
-        die("failed to create pipe channel");
-
-    if (l2_channel_configure(chPipe, "pipe", pipdesc[1]) != L2_OK)
-        die("failed to configure pipe channel");
-#endif
-
     if (l2_channel_stack(chFile, chBuf) != L2_OK)
         die("failed to stack buffer channel on top of file channel");
     
     if (l2_channel_stack(chBuf, chPrefix) != L2_OK)
         die("failed to stack prefix channel on top of buffer channel");
 
-#ifdef WITH_PIPE
-    if (l2_channel_stack(chPrefix, chPipe) != L2_OK)
-        die("failed to stack pipe channel on top of prefix channel");
-#endif
-    
     if (l2_channel_open(chPrefix) != L2_OK)
         die("failed to open channel stack");
 
@@ -159,7 +117,7 @@
         die("failed to attach channel stack into stream");
 
 #ifdef WITH_SYSLOG
-    if ((chSyslog = l2_channel_create(&l2_handler_syslog)) == NULL)   /* Syslog */
+    if ((chSyslog = l2_channel_create(&l2_handler_syslog)) == NULL)  /* Syslog */
         die("failed to create syslog channel");
 
     if (l2_channel_configure(chSyslog, "ident,facility,target,remotehost,logpid",
@@ -173,8 +131,44 @@
         die("failed to attach channel syslog into stream");
 #endif
 
+#ifdef WITH_PIPE
+    if ((chPipe = l2_channel_create(&l2_handler_pipe)) == NULL)      /* Pipe */
+        die("failed to create pipe channel");
+
+    if (l2_channel_configure(chPipe, "pipe", pipdesc[1]) != L2_OK)
+        die("failed to configure pipe channel");
+
+    if (l2_channel_open(chPipe) != L2_OK)
+        die("failed to open pipe channel");
+
+    if (l2_stream_channel(st, chPipe, L2_LEVEL_UPTO(L2_LEVEL_WARNING), L2_LEVEL_NONE) != L2_OK)
+        die("failed to attach channel pipe into stream");
+#endif
+
+#ifdef WITH_SOCKET
+    /* Atenzione! Before doing any socket testing, make sure you have a valid */
+    /* end point listening, or else you will only get an error message when   */
+    /* the thing tries to connect.                                            */
+    if ((chSock = l2_channel_create(&l2_handler_socket)) == NULL)   /* Socket */
+        die("failed to create socket channel");
+
+    if (l2_channel_configure(chSock, "protocol,ipversion,host,port",\
+        IPPROTO_TCP, AF_INET, "localhost", 2002) != L2_OK)
+        die("failed to configure socket ipv4 channel");
+#if 0
+    if (l2_channel_configure(chSock, "protocol,ipversion,host,port",\
+          IPPROTO_TCP, AF_INET6, "0:0:0:0:0:0:0:1", 2002) != L2_OK)
+          die("failed to configure socket ipv6 channel");
+#endif
+    if (l2_channel_open(chSock) != L2_OK)
+        die("failed to open socket channel");
+
+    if (l2_stream_channel(st, chSock, L2_LEVEL_UPTO(L2_LEVEL_WARNING), L2_LEVEL_NONE) != L2_OK)
+        die("failed to attach channel socket into stream");
+#endif
+
 #ifdef WITH_SMTP
-    if ((chSmtp = l2_channel_create(&l2_handler_smtp)) == NULL)   /* SMTP */
+    if ((chSmtp = l2_channel_create(&l2_handler_smtp)) == NULL)      /* SMTP */
         die("failed to create smtp channel");
 
     if (l2_channel_configure(chSmtp, "rcpt,host,port", "rse@engelschall.com", "en1", "25") != L2_OK)
@@ -202,8 +196,6 @@
     if (l2_stream_destroy(st) != L2_OK)
         die("failed to destroy stream");
 
-    close(pipdesc[1]); /* Close the locally made pipe file descriptor */
-    close(pipdesc[0]); /* Close the locally made pipe file descriptor */
     return 0;
 }

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