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ossp - Difference in ossp-pkg/l2/l2_ch_pipe.c versions 1.11 and 1.12
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ossp-pkg/l2/l2_ch_pipe.c 1.11 -> 1.12

--- l2_ch_pipe.c 2001/09/18 14:38:51     1.11
+++ l2_ch_pipe.c 2001/09/19 16:39:44     1.12
@@ -31,39 +31,51 @@
 
 #include <unistd.h>
 #include <signal.h>
+#include <sys/wait.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 */
 
+static l2_result_t hook_open(l2_context_t *, l2_channel_t *); /* prototypes */
+
+
 /* declare private channel configuration */
 typedef struct {
-    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 */
+    int piFd[2];                 /* pipe file descriptor               */
+    int iMode;                   /* execution mode direct or shell     */
+    pid_t Pid;                   /* pid set during fork in hook_open() */
+    char *szCmdpath;             /* path to command and arguments      */
 } l2_ch_pipe_t;
 
 static void catchsignal(int sig, ...)
 {
-    va_list ap;
-    static l2_ch_pipe_t *cfg = NULL;
-
-    va_start(ap, sig);
-    if (sig == 0)
-        cfg = va_arg(ap, l2_ch_pipe_t *);
+    int                  iStatus = 0;
+    va_list              ap      = NULL;
+    static l2_context_t *ctx     = NULL;
+    static l2_channel_t *chan    = NULL;
+
+    if (sig == 0) {
+        va_start(ap, sig);
+        ctx  = va_arg(ap, l2_context_t *);
+        chan = va_arg(ap, l2_channel_t *);
+        va_end(ap);
+    }
     else if (sig == SIGCHLD) {
-        fprintf(stderr, "Pipe: SIGCHLD caught\n");
-        close(cfg->piFd[1]);
-        cfg->piFd[1] = -1; /* TODO: Fill in with new pipe fd */
+/*        TRACE("SIGCHLD caught\n");*/
+        waitpid(((l2_ch_pipe_t *)ctx->vp)->Pid, &iStatus, 0);
+        close(((l2_ch_pipe_t *)ctx->vp)->piFd[1]);
+        ((l2_ch_pipe_t *)ctx->vp)->piFd[1] = -1;
+        if (hook_open(ctx, chan) != L2_OK) { /* TODO: Fix infinit loop! */
+            close(((l2_ch_pipe_t *)ctx->vp)->piFd[1]);
+            ((l2_ch_pipe_t *)ctx->vp)->piFd[1] = -1;
+        }
     }
     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; */
+/*        TRACE("SIGPIPE caught\n");*/
+        close(((l2_ch_pipe_t *)ctx->vp)->piFd[1]);
+        ((l2_ch_pipe_t *)ctx->vp)->piFd[1] = -1;
     }
-    va_end(ap);
 }
 
 /* create channel */
@@ -80,7 +92,6 @@
     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;
@@ -94,26 +105,43 @@
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
     l2_param_t pa[3]; 
     l2_result_t rv;
-    char szMode[16]; /* just eneough for double-byte "direct" and NULL */
+    FILE *File;
+    char *szTemp;
+    char *pbIndex;
 
     /* feed and call generic parameter parsing engine */
-    L2_PARAM_SET(pa[0], mode, CHARPTR, szMode);
+    L2_PARAM_SET(pa[0], mode, CHARPTR, &szTemp);
     L2_PARAM_SET(pa[1], path, STRING, &cfg->szCmdpath);
     L2_PARAM_END(pa[2]);
-    rv = l2_util_setparams(pa, fmt, ap);
+    if ((rv = l2_util_setparams(pa, fmt, ap)) != L2_OK)
+        return rv;
 
-    if (strcmp(szMode, "direct") == NULL)
+    if (strcmp(szTemp, "direct") == NULL)
         cfg->iMode = L2_PIPE_MODEDIRECT;
-    else if (strcmp(szMode, "shell") == NULL)
+    else if (strcmp(szTemp, "shell") == NULL)
         cfg->iMode = L2_PIPE_MODESHELL;
     else
         return L2_ERR_ARG;
 
-    catchsignal(0, cfg); /* initialize signal handler with incoming context */
+    /* check to see if a file exists at the user specified path             */
+    if(cfg->iMode != L2_PIPE_MODESHELL) {
+        szTemp = strdup(cfg->szCmdpath);
+        for (pbIndex = szTemp; *pbIndex != NULL; pbIndex++);
+        *pbIndex = NULL;
+        if (!(File = fopen(szTemp, "r")))
+            return L2_ERR_ARG; /* the command does not exist at the given path  */
+        else
+            fclose(File);
+        free(szTemp);
+        szTemp = NULL;
+        pbIndex = NULL;
+    }
+
+    catchsignal(0, ctx, ch); /* initialize signal handler with context & ch */
     signal(SIGCHLD, (void(*)())catchsignal); /* pipe changes descriptor     */
     signal(SIGPIPE, (void(*)())catchsignal); /* pipe closes reading fd      */
 
-    return rv;
+    return rv; /* all okay */
 }
 
 /**********************************************************
@@ -122,14 +150,15 @@
  **********************************************************/
 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;
+            *szBuf++ = '\0'; /* overwrite whitespace with EOL  */
+        *szArgs++ = szBuf;   /* found the start of a new token */
         while ((*szBuf != '\0') && (*szBuf != ' ') && (*szBuf != '\t'))
             szBuf++;
     }
-    *szArgs = NULL;
+    *szArgs = NULL; /* add a NULL to mark the end of the chain */
 
     if (iCnt <= L2_PIPE_MAXARGS)
         return L2_OK;
@@ -137,47 +166,48 @@
         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)
+/* 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;
+    char *pVec[L2_PIPE_MAXARGS];
+    l2_result_t rv;
+
     /* 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    */
+    memset(pVec, 0, sizeof(pVec));
 
-        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;
+    /* the distinction between modes is necessary, because only executing */
+    /* commands in a shell environment allows usage of variables and such */
+    if (cfg->iMode == L2_PIPE_MODESHELL) {
+        pVec[0] = "/bin/sh";
+        pVec[1] = "-c";
+        pVec[2] = cfg->szCmdpath;
+        pVec[3] = NULL; /* add a NULL to mark the end of the chain   */
+    }
 
-    if ((rv = parse_cmdpath(cfg->szCmdpath, cfg->pVec)) != L2_OK)
-        return rv;
+    else /* plain command execution */
+        if ((rv = parse_cmdpath(cfg->szCmdpath, pVec)) != L2_OK)
+            return rv;
 
-    if (pipe(cfg->piFd) == -1)      /* open the pipe  */
+    if (pipe(cfg->piFd) == -1)                /* open the pipe            */
         return L2_ERR_SYS;
 
-    if ((Pid = fork()) > 0) {       /* parent process */
-        close(cfg->piFd[0]);
+    if ((cfg->Pid = fork()) > 0) {            /* parent process           */
+        close(cfg->piFd[0]);                  /* half-duplex (no reading) */
         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]);
+    else if (cfg->Pid == 0) {                 /* child process            */
+        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     */
+
+        if (execvp(*pVec, pVec) == -1) {      /* launch                   */
+            close(cfg->piFd[0]);              /* cleanup                  */
             cfg->piFd[0] = -1;
-            return L2_ERR_SYS;
+            return L2_ERR_SYS; /* if child returns, we have an error      */
         }
     }
     else /* fork failed  */
@@ -192,12 +222,11 @@
 {
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
 
-    /* validate the pipe fd */
-    if (cfg->piFd[1] == -1)  /* TODO: possibly remove this validation in */
-        return L2_ERR_ARG;   /*       lieu of incoming SIGPIPE signal    */
+    if (cfg->piFd[1] == -1)
+        return L2_ERR_IO;
 
     /* write message to channel pipe */
-    if (write(cfg->piFd[1], buf, buf_size) == -1)
+    else if (write(cfg->piFd[1], buf, buf_size) == -1)
         return L2_ERR_SYS;
 
     return L2_OK;
@@ -221,7 +250,7 @@
     l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
 
     /* destroy channel configuration */
-    free(&cfg->szCmdpath);
+    free(cfg->szCmdpath);
     cfg->szCmdpath = NULL;
     free(cfg);
 

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