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std › process › getEnvMap

getEnvMap

Returns a snapshot of the environment variables of the current process. Any modifications to the resulting EnvMap will not be reflected in the environment, and likewise, any future modifications to the environment will not be reflected in the EnvMap. Caller owns resulting EnvMap and should call its deinit fn when done.

Function parameters

Parameters

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Type definitions in this namespace

Types

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ArgIteratorWindows
Iterator that implements the Windows command-line parsing algorithm.
ArgIteratorGeneralOptions
Optional parameters for `ArgIteratorGeneral`
ArgIterator
Cross-platform command line argument iterator.

Functions in this namespace

Functions

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getCwd
The result is a slice of `out_buffer`, from index `0`.
getCwdAlloc
Caller must free the returned memory.
getEnvMap
Returns a snapshot of the environment variables of the current process.
getEnvVarOwned
Caller must free returned memory.
hasEnvVarConstant
On Windows, `key` must be valid WTF-8.
hasNonEmptyEnvVarConstant
On Windows, `key` must be valid WTF-8.
parseEnvVarInt
Parses an environment variable as an integer.
hasEnvVar
On Windows, if `key` is not valid [WTF-8](https://simonsapin.github.io/wtf-8/),
hasNonEmptyEnvVar
On Windows, if `key` is not valid [WTF-8](https://simonsapin.github.io/wtf-8/),
getenvW
Windows-only.
ArgIteratorGeneral
A general Iterator to parse a string into a set of arguments
args
Holds the command-line arguments, with the program name as the first entry.
argsWithAllocator
You must deinitialize iterator's internal buffers by calling `deinit` when done.
argsAlloc
Caller must call argsFree on result.
getUserInfo
POSIX function which gets a uid from username.
posixGetUserInfo
TODO this reads /etc/passwd.
execv
Replaces the current process image with the executed process.
execve
Replaces the current process image with the executed process.
totalSystemMemory
Returns the total system memory, in bytes as a u64.
cleanExit
Indicate that we are now terminating with a successful exit code.
raiseFileDescriptorLimit
Raise the open file descriptor limit.
createEnvironFromMap
Creates a null-delimited environment variable block in the format
createEnvironFromExisting
Creates a null-delimited environment variable block in the format
createWindowsEnvBlock
Caller must free result.
fatal
Logs an error and then terminates the process with exit code 1.

Error sets in this namespace

Error Sets

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Tells whether calling the `execv` or `execve` functions will be a compile error.

Values

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can_execv
Tells whether calling the `execv` or `execve` functions will be a compile error.
can_spawn
Tells whether spawning child processes is supported (e.g.

Source

Implementation

#
pub fn getEnvMap(allocator: Allocator) GetEnvMapError!EnvMap {
    var result = EnvMap.init(allocator);
    errdefer result.deinit();

    if (native_os == .windows) {
        const ptr = windows.peb().ProcessParameters.Environment;

        var i: usize = 0;
        while (ptr[i] != 0) {
            const key_start = i;

            // There are some special environment variables that start with =,
            // so we need a special case to not treat = as a key/value separator
            // if it's the first character.
            // https://devblogs.microsoft.com/oldnewthing/20100506-00/?p=14133
            if (ptr[key_start] == '=') i += 1;

            while (ptr[i] != 0 and ptr[i] != '=') : (i += 1) {}
            const key_w = ptr[key_start..i];
            const key = try unicode.wtf16LeToWtf8Alloc(allocator, key_w);
            errdefer allocator.free(key);

            if (ptr[i] == '=') i += 1;

            const value_start = i;
            while (ptr[i] != 0) : (i += 1) {}
            const value_w = ptr[value_start..i];
            const value = try unicode.wtf16LeToWtf8Alloc(allocator, value_w);
            errdefer allocator.free(value);

            i += 1; // skip over null byte

            try result.putMove(key, value);
        }
        return result;
    } else if (native_os == .wasi and !builtin.link_libc) {
        var environ_count: usize = undefined;
        var environ_buf_size: usize = undefined;

        const environ_sizes_get_ret = std.os.wasi.environ_sizes_get(&environ_count, &environ_buf_size);
        if (environ_sizes_get_ret != .SUCCESS) {
            return posix.unexpectedErrno(environ_sizes_get_ret);
        }

        if (environ_count == 0) {
            return result;
        }

        const environ = try allocator.alloc([*:0]u8, environ_count);
        defer allocator.free(environ);
        const environ_buf = try allocator.alloc(u8, environ_buf_size);
        defer allocator.free(environ_buf);

        const environ_get_ret = std.os.wasi.environ_get(environ.ptr, environ_buf.ptr);
        if (environ_get_ret != .SUCCESS) {
            return posix.unexpectedErrno(environ_get_ret);
        }

        for (environ) |env| {
            const pair = mem.sliceTo(env, 0);
            var parts = mem.splitScalar(u8, pair, '=');
            const key = parts.first();
            const value = parts.rest();
            try result.put(key, value);
        }
        return result;
    } else if (builtin.link_libc) {
        var ptr = std.c.environ;
        while (ptr[0]) |line| : (ptr += 1) {
            var line_i: usize = 0;
            while (line[line_i] != 0 and line[line_i] != '=') : (line_i += 1) {}
            const key = line[0..line_i];

            var end_i: usize = line_i;
            while (line[end_i] != 0) : (end_i += 1) {}
            const value = line[line_i + 1 .. end_i];

            try result.put(key, value);
        }
        return result;
    } else {
        for (std.os.environ) |line| {
            var line_i: usize = 0;
            while (line[line_i] != 0 and line[line_i] != '=') : (line_i += 1) {}
            const key = line[0..line_i];

            var end_i: usize = line_i;
            while (line[end_i] != 0) : (end_i += 1) {}
            const value = line[line_i + 1 .. end_i];

            try result.put(key, value);
        }
        return result;
    }
}