Allow to set execution environmentHEADv1.4master

* runcap.3: Document changes.
* runcap.c (runcap_start): Set environ if rc->rc_env is not NULL.
(runcap_init): Initialize rc->rc_env with NULL if RCF_ENV is not set.
* runcap.h (struct runcap): New field: rc_env.
(RCF_ENV): New flag.
* t/env.at: New test.
* t/Makefile.am: Add new test.
* t/testsuite.at: Likewise.
* t/rt.c: New option: -e (modify environment).

7 files changed, 188 insertions, 21 deletions

diff --git a/runcap.3 b/runcap.3
index 76dc6cc..2bd3648 100644
--- a/runcap.3
+++ b/runcap.3
@@ -15,3 +15,3 @@
 .\" along with runcap.  If not, see <http://www.gnu.org/licenses/>.
-.TH RUNCAP 2 "January 30, 2020" "RUNCAP" "User Commands"
+.TH RUNCAP 2 "March 14, 2024" "RUNCAP" "User Commands"
 .SH NAME
@@ -69,9 +69,10 @@ struct runcap
 {
-    char *rc_program;    /* [\fIIN\fR] (Path)name of the program to run */ 
-    char **rc_argv;      /* [\fIIN\fR] Argument vector */
-    unsigned rc_timeout; /* [\fIIN\fR] Execution timeout */
+    char *rc_program;    /* [\fIIN\fR] (Path)name of the program to run. */ 
+    char **rc_argv;      /* [\fIIN\fR] Argument vector. */
+    char **rc_env;       /* [\fIIN\fR] Environment variables. */
+    unsigned rc_timeout; /* [\fIIN\fR] Execution timeout. */
     struct stream_capture rc_cap[3]; 
-    pid_t rc_pid;        /* [\fIOUT\fR] PID of the process */
-    int rc_status;       /* [\fIOUT\fR] Termination status */
-    int rc_errno;        /* [\fIOUT\fR] System error code */
+    pid_t rc_pid;        /* [\fIOUT\fR] PID of the process. */
+    int rc_status;       /* [\fIOUT\fR] Termination status. */
+    int rc_errno;        /* [\fIOUT\fR] System error code. */
 };
@@ -98,2 +99,10 @@ the \fBRCF_TIMEOUT\fR bit must be set in \fIflags\fR.  If not set,
 will wait indefinitely.
+.TP
+.B rc_env
+A
+.BR NULL -terminated
+array of environment variables.  Each element (except the last
+.BR NULL )
+has the form "\fIname\fR=\fIvalue\fR".  If initialized, the
+\fBRCF_ENV\fR bit must be set in \fIflags\fR.
 .PP
@@ -478,3 +487,3 @@ Sergey Poznyakoff
 .SH COPYRIGHT
-Copyright \(co 2017--2020 Sergey Poznyakoff
+Copyright \(co 2017--2024 Sergey Poznyakoff
 .br
diff --git a/runcap.c b/runcap.c
index de64f70..56f6974 100644
--- a/runcap.c
+++ b/runcap.c
@@ -262,2 +262,4 @@ timeval_diff(struct timeval const *a, struct timeval const *b)
 
+extern char **environ;
+
 static int
@@ -308,2 +310,4 @@ runcap_start(struct runcap *rc)
 
+		if (rc->rc_env)
+			environ = rc->rc_env;
 		execvp(rc->rc_program ? rc->rc_program : rc->rc_argv[0],
@@ -481,3 +485,4 @@ runcap_init(struct runcap *rc, int flags)
 		rc->rc_timeout = 0;
-
+	if (!(flags & RCF_ENV))
+		rc->rc_env = NULL;
 	if (flags & RCF_STDIN) {
diff --git a/runcap.h b/runcap.h
index 1fbb8f7..011cb06 100644
--- a/runcap.h
+++ b/runcap.h
@@ -49,2 +49,3 @@ struct runcap
 	char **rc_argv;   /* [IN] Argument vector */
+	char **rc_env;    /* [IN] Environment variables */
 	unsigned rc_timeout; /* [IN] Execution timeout */
@@ -60,2 +61,3 @@ struct runcap
 #define RCF_STDIN   0x0004 /* rc_cap[RUNCAP_STDIN] is set */
+#define RCF_ENV     0x0008 /* rc_env is set */
 
diff --git a/t/Makefile.am b/t/Makefile.am
index 9e958ad..1905212 100644
--- a/t/Makefile.am
+++ b/t/Makefile.am
@@ -57,3 +57,4 @@ TESTSUITE_AT = \
   seek00.at\
-  seek01.at
+  seek01.at\
+  env.at
 # Add more files here
diff --git a/t/env.at b/t/env.at
new file mode 100644
index 0000000..42883a1
--- /dev/null
+++ b/t/env.at
@@ -0,0 +1,28 @@
+# Testsuite for runcap - run program and capture its output -*- autotest -*-
+# Copyright (C) 2024 Sergey Poznyakoff
+#
+# Runcap is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Runcap is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with Runcap. If not, see <http://www.gnu.org/licenses/>.
+AT_SETUP([environment modifications])
+AT_KEYWORDS([env environ])
+AT_CHECK([rt -n stdout -e FOO=bar -- /bin/sh -c 'echo $FOO'],
+[0],
+[res=0
+exit code: 0
+stdout: 1 lines, 4 bytes
+stderr: 0 lines, 0 bytes
+stdout listing:
+ 1: bar
+stdout listing ends
+])
+AT_CLEANUP
diff --git a/t/rt.c b/t/rt.c
index 1ecdc3a..bcb49a4 100644
--- a/t/rt.c
+++ b/t/rt.c
@@ -27,2 +27,3 @@
 #include <inttypes.h>
+#include <assert.h>
 #include "runcap.h"
@@ -51,2 +52,6 @@ usage(int code)
 	fprintf(fp, "  -S all|stderr|stdout   selects capture for the next -m, -N, or -s option\n");
+	fprintf(fp, "  -e VAR=NAME            set environment variable\n");
+	fprintf(fp, "  -e -VAR                unset environment variable\n");
+	fprintf(fp, "  -e -                   clear environment (except for PATH,\n");
+	fprintf(fp, "                         HOME, and LOGNAME)\n");
 	fprintf(fp, "  -f FILE                reads stdin from FILE\n");
@@ -236,7 +241,5 @@ readreq_do(struct runcap *rc, struct readreq *req)
 		ssize_t n;
-		
-		if (!buf) {
-			perror("malloc");
-			abort();
-		}
+
+		assert(buf != NULL);
+
 		n = runcap_read(rc, req->what, buf, req->count);
@@ -281,2 +284,119 @@ open_outfile(char *file, int stream, struct runcap *rc, int *flags)
 
+static int
+getenvind(char **env, char const *name)
+{
+        size_t i;
+        for (i = 0; env[i]; i++) {
+                char const *p;
+                char *q;
+
+                for (p = name, q = env[i]; *p == *q; p++, q++)
+                        ;
+                if (*p == 0 && *q == '=') {
+                        return i;
+                }
+        }
+        return -1;
+}
+
+char **
+envdup(char **env)
+{
+	int i;
+	char **new_env;
+
+	for (i = 0; env[i]; i++)
+		;
+
+	new_env = calloc(i+1, sizeof(env[0]));
+	assert(new_env != NULL);
+
+	for (i = 0; env[i]; i++) {
+		new_env[i] = strdup(env[i]);
+		assert(new_env[i] != NULL);
+	}
+	new_env[i] = NULL;
+
+	return new_env;
+}
+
+char **envupdate(char **, char *);
+
+char **
+envclear(char **env)
+{
+	int i, j;
+	static char *keep[] = {
+		"PATH",
+		"HOME",
+		"LOGNAME",
+		NULL
+	};
+	char **new_env = calloc(1, sizeof(new_env[0]));
+	assert(new_env != NULL);
+	for (i = 0; keep[i]; i++) {
+		j = getenvind(env, keep[i]);
+		if (j != -1)
+			new_env = envupdate(new_env, env[j]);
+	}
+	for (i = 0; env[i]; i++)
+		free(env[i]);
+	free(env);
+	return new_env;
+}
+
+char **
+envappend(char **env, char *arg)
+{
+	int i;
+
+	for (i = 0; env[i]; i++)
+		;
+	env = realloc(env, (i+2) * sizeof(env[0]));
+	assert(env != NULL);
+	env[i] = strdup(arg);
+	assert(env[i] != NULL);
+	env[i+1] = NULL;
+	return env;
+}
+
+char **
+envdelete(char **env, char *arg)
+{
+	int i = getenvind(env, arg);
+	if (i != -1) {
+		int n;
+		for (n = 0; env[n]; n++)
+			;
+		free(env[i]);
+		memmove(env + i, env + i + 1, (n - i) * sizeof(env[0]));
+	}
+	return env;
+}
+
+extern char **environ;
+
+char **
+envupdate(char **env, char *arg)
+{
+	if (env == NULL)
+		env = envdup(environ);
+	if (*arg == '-') {
+		if (arg[1] == 0)
+			env = envclear(env);
+		else
+			env = envdelete(env, arg+1);
+	} else {
+		int i = getenvind(env, arg);
+		if (i == -1)
+			env = envappend(env, arg);
+		else {
+			free(env[i]);
+			env[i] = strdup(arg);
+			assert(env[i] != NULL);
+		}
+	}
+	return env;
+}
+
 int
@@ -308,4 +428,9 @@ main(int argc, char **argv)
 		progname = argv[0];
-	while ((c = getopt(argc, argv, "?f:iNn:mo:p:r:S:s:t:")) != EOF) {
+	memset(&rc, 0, sizeof(rc));
+	while ((c = getopt(argc, argv, "?e:f:iNn:mo:p:r:S:s:t:")) != EOF) {
 		switch (c) {
+		case 'e':
+			rc.rc_env = envupdate(rc.rc_env, optarg);
+			rcf |= RCF_ENV;
+			break;
 		case 'f':
@@ -327,6 +452,3 @@ main(int argc, char **argv)
 				buffer = malloc(size + 1);
-				if (!buffer) {
-					error("not enough memory");
-					exit(1);
-				}
+				assert(buffer != NULL);
 				
diff --git a/t/testsuite.at b/t/testsuite.at
index a3dd7c9..bbce1ff 100644
--- a/t/testsuite.at
+++ b/t/testsuite.at
@@ -34,2 +34,2 @@ m4_include([read.at])
 m4_include([redirect.at])
-
+m4_include([env.at])