--- 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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