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Commit 46ccee6e authored by David Ng's avatar David Ng Committed by Steve Kondik
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init: Allow basic environment variable expansion in env assignment 

Allow environment variable expansion in 'export' command if the
value begins with "${_var_}" (where "${_var_}" will be replaced
with the current value of environment variable _var_).  Expansion
will only occur one time.

e.g.
export BOOTCLASSPATH ${BOOTCLASSPATH}:/system/framework/abc.jar
(cherry picked from commit 7940299507f15055851a6e8b61ae8d8a7d7f3484)

Change-Id: If9e4adfa1aba2c7a4ca243978ced3c46c2cb4d73
parent b34f581c

init/init.c

+86 −2
Original line number Diff line number Diff line
@@ -105,21 +105,105 @@ static unsigned emmc_boot = 0; 


static unsigned charging_mode = 0;



static const char *expand_environment(const char *val)

{

    int n;

    const char *prev_pos = NULL, *copy_pos;

    size_t len, prev_len = 0, copy_len;

    char *expanded;



    /* Basic expansion of environment variable; for now

       we only assume 1 expansion at the start of val

       and that it is marked as ${var} */

    if (!val) {

        return NULL;

    }



    if ((val[0] == '$') && (val[1] == '{')) {

        for (n = 0; n < 31; n++) {

            if (ENV[n]) {

                len = strcspn(ENV[n], "=");

                if (!strncmp(&val[2], ENV[n], len)

                      && (val[2 + len] == '}')) {

                    /* Matched existing env */

                    prev_pos = &ENV[n][len + 1];

                    prev_len = strlen(prev_pos);

                    break;

                }

            }

        }

        copy_pos = index(val, '}');

        if (copy_pos) {

            copy_pos++;

            copy_len = strlen(copy_pos);

        } else {

            copy_pos = val;

            copy_len = strlen(val);

        }

    } else {

        copy_pos = val;

        copy_len = strlen(val);

    }



    len = prev_len + copy_len + 1;

    expanded = malloc(len);

    if (expanded) {

        if (prev_pos) {

            snprintf(expanded, len, "%s%s", prev_pos, copy_pos);

        } else {

            snprintf(expanded, len, "%s", copy_pos);

        }

    }



    /* caller free */

    return expanded;

}



/* add_environment - add "key=value" to the current environment */

int add_environment(const char *key, const char *val)

{

    int n;

    const char *expanded;



    expanded = expand_environment(val);

    if (!expanded) {

        goto failed;

    }



    for (n = 0; n < 31; n++) {

        if (!ENV[n]) {

            size_t len = strlen(key) + strlen(val) + 2;

            size_t len = strlen(key) + strlen(expanded) + 2;

            char *entry = malloc(len);

            snprintf(entry, len, "%s=%s", key, val);

            if (!entry) {

                goto failed_cleanup;

            }

            snprintf(entry, len, "%s=%s", key, expanded);

            free((char *)expanded);

            ENV[n] = entry;

            return 0;

        } else {

            char *entry;

            size_t len = strlen(key);

            if(!strncmp(ENV[n], key, len) && ENV[n][len] == '=') {

                len = len + strlen(expanded) + 2;

                entry = malloc(len);

                if (!entry) {

                    goto failed_cleanup;

                }



                free((char *)ENV[n]);

                snprintf(entry, len, "%s=%s", key, expanded);

                free((char *)expanded);

                ENV[n] = entry;

                return 0;

            }

        }

    }



failed_cleanup:

    free((char *)expanded);

failed:

    ERROR("Fail to add env variable: %s. Not enough memory!", key);

    return 1;

}