openmpi/src/util/environ.c

/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 The Trustees of the University of Tennessee.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */

#include "ompi_config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "include/constants.h"
#include "util/printf.h"
#include "util/argv.h"
#include "util/environ.h"


/*
 * Merge two environ-like char arrays, ensuring that there are no
 * duplicate entires
 */
char **ompi_environ_merge(char **minor, char **major)
{
    int i;
    char **ret = NULL;
    char *name, *value;

    /* Check for bozo cases */

    if (NULL == major) {
        if (NULL == minor) {
            return NULL;
        } else {
            return ompi_argv_copy(minor);
        }
    }

    /* First, copy major */

    ret = ompi_argv_copy(major);

    /* Do we have something in minor? */

    if (NULL == minor) {
        return ret;
    }

    /* Now go through minor and call ompi_setenv(), but with overwrite
       as false */

    for (i = 0; NULL != minor[i]; ++i) {
        value = strchr(minor[i], '=');
        if (NULL == value) {
            ompi_setenv(minor[i], NULL, false, &ret);
        } else {

            /* strdup minor[i] in case it's a constat string */

            name = strdup(minor[i]);
            value = name + (value - minor[i]);
            *value = '\0';
            ompi_setenv(name, value + 1, false, &ret);
            free(name);
        }
    }

    /* All done */

    return ret;
}


/*
 * Portable version of setenv(), allowing editing of any environ-like
 * array
 */
int ompi_setenv(const char *name, const char *value, bool overwrite,
                char ***env)
{
    int i;
    char *newvalue, *compare;
    size_t len;

    /* Make the new value */

    if (NULL == value) {
        asprintf(&newvalue, "%s=", name);
    } else {
        asprintf(&newvalue, "%s=%s", name, value);
    }
    if (NULL == newvalue) {
        return OMPI_ERR_OUT_OF_RESOURCE;
    }

    /* Check the bozo case */

    if (NULL == env) {
        return OMPI_ERR_BAD_PARAM;
    } else if (NULL == *env) {
        i = 0;
        ompi_argv_append(&i, env, newvalue);
        return OMPI_SUCCESS;
    }

    /* Make something easy to compare to */

    asprintf(&compare, "%s=", name);
    if (NULL == compare) {
        free(newvalue);
        return OMPI_ERR_OUT_OF_RESOURCE;
    }
    len = strlen(compare);

    /* Look for a duplicate that's already set in the env */

    for (i = 0; (*env)[i] != NULL; ++i) {
        if (0 == strncmp((*env)[i], compare, len)) {
            if (overwrite) {
                free((*env)[i]);
                (*env)[i] = newvalue;
                free(compare);
                return OMPI_SUCCESS;
            } else {
                free(compare);
                free(newvalue);
                return OMPI_EXISTS;
            }
        }
    }

    /* If we found no match, append this value */

    i = ompi_argv_count(*env);
    ompi_argv_append(&i, env, newvalue);

    /* All done */

    free(compare);
    free(newvalue);
    return OMPI_SUCCESS;
}


/*
 * Portable version of unsetenv(), allowing editing of any
 * environ-like array
 */
int ompi_unsetenv(const char *name, char ***env)
{
    int i;
    char *compare;
    size_t len;
    bool found;

    /* Make something easy to compare to */

    asprintf(&compare, "%s=", name);
    if (NULL == compare) {
        return OMPI_ERR_OUT_OF_RESOURCE;
    }
    len = strlen(compare);

    /* Look for a duplicate that's already set in the env.  If we find
       it, free it, and then start shifting all elements down one in
       the array. */

    found = false;
    for (i = 0; (*env)[i] != NULL; ++i) {
        if (found) {
            (*env)[i] = (*env)[i + 1];
        } else if (0 == strncmp((*env)[i], compare, len)) {
            free((*env)[i]);
            (*env)[i] = (*env)[i + 1];
            found = true;
        }
    }

    /* All done */

    return (found) ? OMPI_SUCCESS : OMPI_ERR_NOT_FOUND;
}