dotenv.c

#include "../include/dotenv.h"
#include "../include/str.h"
 
#include <ctype.h>   // for isspace
#include <errno.h>   // for errno
#include <stdio.h>   // for fprintf, stderr, fopen, fgets, fclose
#include <string.h>  // for strlen, strchr, memset
 
static char* remove_quotes(char* str) {
    if (str == NULL) {
        return NULL;
    }
 
    size_t len = strlen(str);
    if (len < 2) {
        return str;
    }
 
    // Check for matching quotes
    if ((str[0] == '"' && str[len - 1] == '"') || (str[0] == '\'' && str[len - 1] == '\'')) {
        str[len - 1] = '\0';
        return str + 1;
    }
 
    return str;
}
 
static bool interpolate(const char* value, char* result, size_t result_size) {
    if (value == NULL || result == NULL || result_size == 0) {
        return false;
    }
 
    size_t result_len = 0;
    const char* ptr = value;
    memset(result, 0, result_size);
 
    while (*ptr && result_len < result_size - 1) {
        // Look for variable interpolation pattern: ${VAR_NAME}
        if (*ptr == '$' && *(ptr + 1) == '{') {
            const char* start = ptr + 2;
            const char* end = strchr(start, '}');
 
            if (end == NULL) {
                // Malformed interpolation - copy literal characters
                fprintf(stderr, "Warning: Unclosed variable reference starting at position %td\n", ptr - value);
                result[result_len++] = *ptr++;
                continue;
            }
 
            // Extract variable name
            size_t var_name_len = (size_t)(end - start);
            if (var_name_len == 0) {
                // Empty variable name: ${}
                fprintf(stderr, "Warning: Empty variable name\n");
                ptr = end + 1;
                continue;
            }
 
            if (var_name_len >= MAX_VAR_NAME_LEN) {
                fprintf(stderr, "Error: Variable name too long (max %d)\n", MAX_VAR_NAME_LEN - 1);
                return false;
            }
 
            char var_name[MAX_VAR_NAME_LEN] = {0};
            snprintf(var_name, sizeof(var_name), "%.*s", (int)var_name_len, start);
 
            // Get variable value from environment
            const char* var_value = GETENV(var_name);
            if (var_value != NULL) {
                size_t var_value_len = strlen(var_value);
                // Check if we have enough space (account for null terminator)
                if (result_len + var_value_len >= result_size) {
                    fprintf(stderr, "Error: Result buffer too small for interpolation\n");
                    return false;
                }
 
                memcpy(result + result_len, var_value, var_value_len);
                result_len += var_value_len;
            } else {
                fprintf(stderr, "Warning: Environment variable '%s' not found, skipping\n", var_name);
            }
 
            ptr = end + 1;
        } else {
            // Regular character - copy as-is
            result[result_len++] = *ptr++;
        }
    }
 
    // Check if we ran out of buffer space
    if (*ptr != '\0') {
        fprintf(stderr, "Error: Result buffer too small\n");
        return false;
    }
 
    result[result_len] = '\0';
    return true;
}
 
static bool process_env_pair(char* key, char* value) {
    if (key == NULL || value == NULL) {
        return false;
    }
 
    // Trim key
    str_trim(key);
    if (*key == '\0') {
        return false;
    }
 
    // Trim and unquote value
    str_trim(value);
    value = remove_quotes(value);
 
    // Check if interpolation is needed
    if (strchr(value, '$') != NULL && strchr(value, '{') != NULL && strchr(value, '}') != NULL) {
        char interpolated_value[MAX_LINE_LENGTH] = {0};
        if (!interpolate(value, interpolated_value, sizeof(interpolated_value))) {
            fprintf(stderr, "Error: Failed to interpolate value for key '%s'\n", key);
            return false;
        }
 
        if (SETENV(key, interpolated_value, 1) != 0) {
            fprintf(stderr, "Error: Failed to set environment variable '%s': %s\n", key, strerror(errno));
            return false;
        }
    } else {
        if (SETENV(key, value, 1) != 0) {
            fprintf(stderr, "Error: Failed to set environment variable '%s': %s\n", key, strerror(errno));
            return false;
        }
    }
 
    return true;
}
 
bool load_dotenv(const char* path) {
    if (path == NULL) {
        return false;
    }
 
    FILE* file = fopen(path, "r");
    if (file == NULL) {
        fprintf(stderr, "Error: Cannot open file '%s': %s\n", path, strerror(errno));
        return false;
    }
 
    char line[MAX_LINE_LENGTH] = {0};
    size_t line_number = 0;
    bool had_errors = false;
 
    while (fgets(line, sizeof(line), file) != NULL) {
        line_number++;
 
        // Remove trailing newline
        size_t len = strlen(line);
        if (len > 0 && line[len - 1] == '\n') {
            line[len - 1] = '\0';
        }
        str_trim(line);
 
        // Skip empty lines and comments
        if (*line == '\0' || *line == '#') {
            continue;
        }
 
        // Find the '=' separator
        char* equals = strchr(line, '=');
        if (equals == NULL) {
            fprintf(stderr, "Warning: Invalid line %zu (no '=' found): %s\n", line_number, line);
            had_errors = true;
            continue;
        }
 
        // Split into key and value
        *equals = '\0';
        char* key = line;
        char* value = equals + 1;
 
        if (!process_env_pair(key, value)) {
            fprintf(stderr, "Warning: Failed to process line %zu\n", line_number);
            had_errors = true;
        }
    }
 
    if (ferror(file)) {
        fprintf(stderr, "Error: Failed to read from file '%s'\n", path);
        fclose(file);
        return false;
    }
 
    fclose(file);
    return !had_errors;
}