source: trunk/third/sysinfo/run.c @ 11115

/*
 * Copyright (c) 1992-1996 Michael A. Cooper.
 * This software may be freely used and distributed provided it is not sold 
 * for profit or used for commercial gain and the author is credited 
 * appropriately.
 */

#ifndef lint
static char *RCSid = "$Id: run.c,v 1.1.1.2 1998-02-12 21:32:01 ghudson Exp $";
#endif

/*
 * Things related to running system commands.
 */

#include "defs.h"

/*
 * Need default environment for some OS's like HP-UX.
 */
static char                    *DefEnviron[] = {
    "HOME=/dev/null",
    NULL };
extern char                   **Environ;
uid_t                           SavedUserID;

/*
 * Set our User ID.
 */
int SetUserID(RealUID, EffectUID)
    uid_t                       RealUID;
    uid_t                       EffectUID;
{
    if (Debug) printf("SetUserID(%d, %d) current: ruid=%d euid=%d\n", 
                      RealUID, EffectUID, getuid(), geteuid());

    if (setreuid(RealUID, EffectUID) == -1) {
        if (Debug) Error("setreuid to %d, %d failed: %s", 
                         RealUID, EffectUID, SYSERR);
        return(-1);
    }

    if (Debug) printf("SetUserID(%d, %d) new: ruid=%d euid=%d\n",
                      RealUID, EffectUID, getuid(), geteuid());

    return(0);
}

/*
 * Set environment variable "Key" to be "Value".
 */
int SetEnv(Key, Value)
    char                       *Key;
    char                       *Value;
{
    static char                 Buff[BUFSIZ];

    (void) sprintf(Buff, "%s=%s", Key, (Value) ? Value : "");
    if (putenv(strdup(Buff)) != 0) {
        if (Debug) Error("putenv(%s) failed.", Buff);
        return(-1);
    }

    return(0);
}

/*
 * Initialize environment before executing external command.
 */
int ExecInit(WithPrivs)
    int                         WithPrivs;
{
    static int                  First = TRUE;
    register char             **PtrPtr;

    if (First) {
        First = FALSE;
        SavedUserID = (uid_t) -1;
        /*
         * Remove environment variables considered to be a security risk.
         */
        for (PtrPtr = Environ; PtrPtr && *PtrPtr; ++PtrPtr) {
            if (EQN(*PtrPtr, "IFS=", 4)) {
                if (SetEnv("IFS", NULL) < 0)
                    return(-1);
            } else if (EQN(*PtrPtr, "LD_", 3)) {
                if (SetEnv(*PtrPtr, NULL) < 0)
                    return(-1);
            }
        }
    }

    /*
     * Only change user ID if we're setuid root (uid==0).
     */
    if (!WithPrivs && (geteuid() == 0) && ((SavedUserID = getuid()) != 0))
        if (SetUserID(0, SavedUserID) == -1)
            return(-1);

    return(0);
}

/*
 * Reset things after executing external command.
 */
int ExecEnd(WithPrivs)
    int                         WithPrivs;
{
    if (SavedUserID != (uid_t)-1 && SetUserID(SavedUserID, 0) == -1)
        return(-1);
    return(0);
}

/*
 * Run a list of commands (found in cmds) and return command output.
 */
extern char *RunCmds(Cmds, WithPrivs)
    char                      **Cmds;
    int                         WithPrivs;
{
    static char                 Buf[BUFSIZ];
    int                         l;
    int                         Done = 0;
    FILE                       *pf;
    register char              *p;
    char                      **Cmd;

    if (ExecInit(WithPrivs) != 0)
            return((char *)NULL);

    Buf[0] = C_NULL;
    for (Cmd = Cmds; Cmd != NULL && *Cmd != NULL && !Done; ++Cmd) {
        /*
         * If this command has any args, nuke them for the access() test.
         */
        strcpy(Buf, *Cmd);
        p = strchr(Buf, ' ');
        if (p != NULL)
            *p = C_NULL;

        if (access(Buf, X_OK) != 0)
            continue;

        if (Debug) printf("RunCmd '%s' %s Privs\n", 
                          *Cmd, (WithPrivs) ? "With" : "Without");

        if ((pf = popen(*Cmd, "r")) == NULL)
            continue;
        if (fgets(Buf, sizeof(Buf), pf) == NULL) {
            pclose(pf);
            continue;
        }
        pclose(pf);

        l = strlen(Buf);
        if (Buf[l-1] == '\n') 
            Buf[l-1] = C_NULL;

        Done = TRUE;
    }
 
    if (ExecEnd(WithPrivs) != 0)
            return((char *)NULL);

    return((Buf[0]) ? Buf : (char *)NULL);
}

/*
 * Wait for a given process to exit and return
 * that processes exit status.
 */
#if     WAIT_TYPE == WAIT_WAITPID
int WaitForProc(ProcID)
    pid_t                       ProcID;
{
    pid_t                       RetProcID;
    waitarg_t                   ProcStatus;

    RetProcID = waitpid(ProcID, &ProcStatus, 0);

    if (RetProcID == ProcID)
        if (WIFEXITED(ProcStatus))
            return(WAITEXITSTATUS(ProcStatus));
        else {
            Error("waitpid(%d, , 0) failed and returned %d: %s.", 
                  ProcID, RetProcID, SYSERR);
            return(-1);
        }
    else
        return(-1);
}
#endif  /* WAIT_WAITPID */
#if     WAIT_TYPE == WAIT_WAIT4
int WaitForProc(ProcID)
    pid_t                       ProcID;
{
    pid_t                       RetProcID;
    waitarg_t                   ProcStatus;

    RetProcID = wait4(ProcID, &ProcStatus, 0, NULL);

    if (RetProcID == ProcID)
        if (WIFEXITED(ProcStatus))
            return(WAITEXITSTATUS(ProcStatus));
        else {
            Error("wait4(%d) failed and returned %d: %s.", 
                  ProcID, RetProcID, SYSERR);
            return(-1);
        }
    else
        return(-1);
}
#endif  /* WAIT_WAIT4 */

/*
 * Execute a command with given arguments.
 */
int Execute(Cmd, Argv, Env, WithPrivs, StdOut, StdErr)
    char                       *Cmd;
    char                      **Argv;
    char                      **Env;
    int                         WithPrivs;
    int                         StdOut;
    int                         StdErr;
{
    pid_t                       ProcID = 0;
    int                         Status;
    register char             **PtrPtr;

    if (access(Cmd, X_OK) != 0)
        return(-1);

    if (!Env)
        Env = DefEnviron;

    if (Debug) {
        printf("Execute '%s'", Cmd);
        for (PtrPtr = Argv; PtrPtr && *PtrPtr; ++PtrPtr)
            printf(" '%s'", *PtrPtr);
        printf("\t%s Privs\n", (WithPrivs) ? "With" : "Without");
    }

    ProcID = fork();
    if (ProcID < 0) {
        Error("Fork failed: %s", SYSERR);
        return(-1);
    } else if (ProcID == 0) {
        /*
         * Child
         */
        if (StdOut >= 0)
            if (dup2(StdOut, fileno(stdout)) < 0)
                Error("dup2(%d, stdout) failed: %s.", StdOut);
        if (StdErr >= 0)
            if (dup2(StdErr, fileno(stderr)) < 0)
                Error("dup2(%d, stderr) failed: %s.", StdErr);
        ExecInit(WithPrivs);
        execve(Cmd, Argv, Env);
        Error("Execve \"%s\" failed: %s", Cmd, SYSERR);
        exit(127);
    } else {
        /*
         * Parent
         */
        Status = WaitForProc(ProcID);
        if (Debug) printf("\tCommand '%s' exited %d.\n", Cmd, Status);
        return(Status);
    }
    return(-1);
}

#if     defined(RUN_TEST_CMD)
static char                    *RunTestCmd[] = RUN_TEST_CMD;
#endif  /* RUN_TEST_CMD */

/*
 * Get the Argument Vector for the command to run.
 */
static char **GetRunArgv(Command)
    char                       *Command;
{
    static char               **Argv = NULL;
    char                       *Base;
#if     defined(RUN_TEST_CMD)
    register char             **ArgvPtr;
    register char             **PtrPtr;
    register int                Count;

    for (Count = 0, PtrPtr = RunTestCmd; PtrPtr && *PtrPtr; ++PtrPtr, ++Count);

    if (Argv)
        (void) free(Argv);
    ArgvPtr = Argv = (char **) xmalloc((Count+2) * sizeof(char *));

    for (PtrPtr = RunTestCmd; PtrPtr && *PtrPtr; ++PtrPtr, ++ArgvPtr)
        *ArgvPtr = *PtrPtr;
    *ArgvPtr = Command;
    *++ArgvPtr = NULL;
#else   /* !RUN_TEST_CMD */
    Base = strrchr(Command, '/');
    if (Base)
        ++Base;
    else
        Base = Command;
    if (Argv)
        (void) free(Argv);
    Argv = (char **) xmalloc(4 * sizeof(char *));
    Argv[0] = Command;
    Argv[1] = Base;
    Argv[2] = NULL;
#endif  /* RUN_TEST_CMD */

    return(Argv);
}
    

/*
 * Run a list of test files.  Each test file is run and if the
 * exit status is 0, we return the basename of the command.
 * e.g. If "/bin/vax" exists and returns status 0, return string "vax".
 */
extern char *RunTestFiles(Cmds)
    char                      **Cmds;
{
    char                      **Cmd;
    char                      **RunEnv;
    char                      **Argv;
    char                       *Name = NULL;
    register char              *p;
    static char                 Buf[BUFSIZ];
    int                         StdOut = -1;
    int                         StdErr = -1;

    /*
     * Setup stdout/stderr to go to /dev/null since we
     * only care about the exit status of commands.
     */
    if (!Debug) {
        StdOut = open(_PATH_NULL, O_WRONLY);
        StdErr = open(_PATH_NULL, O_WRONLY);
    }

    for (Cmd = Cmds; Name == NULL && Cmd != NULL && *Cmd != NULL; ++Cmd) {
        /*
         * If this command has any args, nuke them for the access() test.
         */
        strcpy(Buf, *Cmd);
        p = strchr(Buf, ' ');
        if (p != NULL)
            *p = C_NULL;

        if (access(Buf, X_OK) != 0)
            continue;

        /*
         * Execute the command with a NULL environment for security
         * reasons.
         */
        Argv = GetRunArgv(*Cmd);
        if (Execute(Argv[0], &Argv[1], (char **)NULL, 0, StdOut, StdErr) != 0)
            continue;

        /*
         * The name of this architecture is the last part of the Cmd name.
         */
        strcpy(Buf, *Cmd);
        p = strrchr(Buf, '/');
        if (p != NULL)
            ++p;
        Name = p;
    }

    if (StdOut >= 0)
        (void) close(StdOut);
    if (StdErr >= 0)
        (void) close(StdErr);

    return(Name);
}