hare

commit aef0a97bedd46608db499196f239c1a529801432
parent 25c165ad428a6eb5d2942c782eda8b128a8f5cff
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sat,  6 Mar 2021 14:48:03 -0500

os::exec: add setenv

Diffstat:
M
os/exec/cmd+linux.ha
 | 
8
++++----
M
os/exec/cmd.ha
 | 
33
++++++++++++++++++++++++++++++---
M
os/exec/types.ha
 | 
8
++++----

3 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/os/exec/cmd+linux.ha b/os/exec/cmd+linux.ha
@@ -48,10 +48,10 @@ fn platform_exec(cmd: *command) os_error = {
 	append(argv, null);
 
 	let envp: nullable *[*]nullable *const char = null;
-	if (len(cmd.envp) != 0) {
-		let env: []nullable *const char = alloc([], len(cmd.envp) + 1);
-		for (let i = 0z; i < len(cmd.envp); i += 1) {
-			append(env, strings::to_c(cmd.envp[i]));
+	if (len(cmd.env) != 0) {
+		let env: []nullable *const char = alloc([], len(cmd.env) + 1);
+		for (let i = 0z; i < len(cmd.env); i += 1) {
+			append(env, strings::to_c(cmd.env[i]));
 		};
 		append(env, null);
 		envp = env: *[*]nullable *const char;
diff --git a/os/exec/cmd.ha b/os/exec/cmd.ha
@@ -1,3 +1,4 @@
+use ascii;
 use os;
 use strings;
 
@@ -26,11 +27,11 @@ export fn cmd(name: str, args: str...) (command | error) = {
 				p: platform_cmd => p,
 			},
 		argv = alloc([], len(args) + 1z),
-		envp = alloc([], len(env)),
+		env = alloc([], len(env)),
 		...
 	};
 	append(cmd.argv, name, ...args);
-	append(cmd.envp, ...env);
+	append(cmd.env, ...env);
 	return cmd;
 };
 
@@ -61,7 +62,33 @@ export fn start(cmd: *command) (error | process) = {
 // Empties the environment variables for the command. By default, the command
 // inherits the environment of the parent process.
 export fn clearenv(cmd: *command) void = {
-	cmd.envp = [];
+	cmd.env = [];
+};
+
+// Adds or sets a variable in the command environment. This does not affect the
+// current process environment. The 'key' must be a valid environment variable
+// name per POSIX definition 3.235. This includes underscores and alphanumeric
+// ASCII characters, and cannot begin with a number.
+export fn setenv(cmd: *command, key: str, value: str) void = {
+	let iter = strings::iter(key);
+	for (let i = 0z; true; i += 1) match (strings::next(&iter)) {
+		void => break,
+		r: rune => if (i == 0) assert(r == '_' || ascii::isalpha(r),
+			"Invalid environment variable")
+		else assert(r == '_' || ascii::isalnum(r),
+			"Invalid environment variable"),
+	};
+
+	// XXX: This can be a binary search
+	let fullkey = strings::concat(key, "=");
+	defer free(fullkey);
+	for (let i = 0z; i < len(cmd.env); i += 1) {
+		if (strings::has_prefix(cmd.env[i], fullkey)) {
+			delete(cmd.env[i]);
+			break;
+		};
+	};
+	append(cmd.env, strings::concat(fullkey, value));
 };
 
 fn lookup(name: str) (platform_cmd | void) = {
diff --git a/os/exec/types.ha b/os/exec/types.ha
@@ -2,20 +2,20 @@
 export type command = struct {
 	platform: platform_cmd,
 	argv: []str,
-	envp: []str,
+	env: []str,
 };
 
 // Returned when path resolution fails to find a command by its name.
-export type nocmd = void;
+export type nocmd = void!;
 
 // An error provided by the operating system.
 export type os_error = struct {
 	string: *fn(data: *void) str,
 	data: *void,
-};
+}!;
 
 // All errors that can be returned from os::exec.
-export type error = (nocmd | os_error);
+export type error = (nocmd | os_error)!;
 
 // Returns a human-readable message for the given error.
 export fn errstr(err: error) const str = {