pkgtools

commit ce2b872a0f5883a7635d02ec07ddbb35da346d36
parent 03db2dc85f52de0ed7cb46aed0a6ce7ceea33305
Author: sin <sin@2f30.org>
Date:   Thu, 12 Jun 2014 00:25:50 +0100

Lock the package database before using it

Diffstat:
M
Makefile
 | 
1
+
M
infopkg.c
 | 
5
+++++
M
installpkg.c
 | 
31
+++++++++++++++++++++++++++++++
A
lock.c
 | 
65
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
removepkg.c
 | 
5
+++++
M
util.h
 | 
3
+++

6 files changed, 110 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -4,6 +4,7 @@ include config.mk
 .SUFFIXES: .c .o
 
 LIB = \
+	lock.o \
 	strlcat.o \
 	strlcpy.o
 
diff --git a/infopkg.c b/infopkg.c
@@ -32,6 +32,7 @@ main(int argc, char *argv[])
 	char *prefix = "/";
 	char path[PATH_MAX];
 	int Oflag = 0;
+	int lockfd;
 	int i;
 	int r;
 
@@ -56,6 +57,8 @@ main(int argc, char *argv[])
 		return EXIT_FAILURE;
 	}
 
+	lockfd = lockdb();
+
 	dir = opendir("var/pkg");
 	if (!dir) {
 		fprintf(stderr, "opendir %s: %s\n", "var/pkg",
@@ -79,6 +82,8 @@ main(int argc, char *argv[])
 
 	closedir(dir);
 
+	unlockdb(lockfd);
+
 	return EXIT_SUCCESS;
 }
 
diff --git a/installpkg.c b/installpkg.c
@@ -34,9 +34,12 @@ usage(void)
 int
 main(int argc, char *argv[])
 {
+	int r;
 	int i;
+	char cwd[PATH_MAX];
 	char *prefix = "/";
 	int fflag = 0;
+	int lockfd;
 
 	ARGBEGIN {
 	case 'v':
@@ -55,6 +58,24 @@ main(int argc, char *argv[])
 	if (argc < 1)
 		usage();
 
+	getcwd(cwd, sizeof(cwd));
+
+	r = chdir(prefix);
+	if (r < 0) {
+		fprintf(stderr, "chdir %s: %s\n", prefix,
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	lockfd = lockdb();
+
+	r = chdir(cwd);
+	if (r < 0) {
+		fprintf(stderr, "chdir %s: %s\n", prefix,
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
 	checkdb(prefix);
 	for (i = 0; i < argc; i++) {
 		if (vflag == 1)
@@ -71,6 +92,16 @@ main(int argc, char *argv[])
 		extract(prefix, argv[i]);
 		printf("installed %s\n", argv[i]);
 	}
+
+	r = chdir(prefix);
+	if (r < 0) {
+		fprintf(stderr, "chdir %s: %s\n", prefix,
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	unlockdb(lockfd);
+
 	return EXIT_SUCCESS;
 }
 
diff --git a/lock.c b/lock.c
@@ -0,0 +1,65 @@
+/* See LICENSE file for copyright and license details. */
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define LOCKPATH "var/pkg/.lock"
+
+/* lock the package dabatase - assumes cwd is the root prefix */
+int
+lockdb(void)
+{
+	struct flock fl;
+	int r;
+	int fd;
+
+	fl.l_type = F_WRLCK;
+	fl.l_whence = SEEK_SET;
+	fl.l_start = 0;
+	fl.l_len = 0;
+	fl.l_pid = getpid();
+
+	fd = open(LOCKPATH, O_WRONLY | O_CREAT, 0600);
+	if (fd < 0) {
+		fprintf(stderr, "failed to create lockfile: %s\n",
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	r = fcntl(fd, F_SETLKW, &fl);
+	if (r < 0) {
+		fprintf(stderr, "failed to obtain lock: %s\n",
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	return fd;
+}
+
+/* unlock the package dabatase - assumes cwd is the root prefix */
+void
+unlockdb(int fd)
+{
+	struct flock fl;
+	int r;
+
+	fl.l_type = F_UNLCK;
+	fl.l_whence = SEEK_SET;
+	fl.l_start = 0;
+	fl.l_len = 0;
+	fl.l_pid = getpid();
+
+	r = fcntl(fd, F_SETLKW, &fl);
+	if (r < 0) {
+		fprintf(stderr, "failed to clear lock: %s\n",
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	close(fd);
+
+	unlink(LOCKPATH);
+}
diff --git a/removepkg.c b/removepkg.c
@@ -38,6 +38,7 @@ main(int argc, char *argv[])
 	struct dirent *dp;
 	char filename[PATH_MAX];
 	char *prefix = "/";
+	int lockfd;
 	int found = 0;
 	int r;
 	int i;
@@ -66,6 +67,8 @@ main(int argc, char *argv[])
 		return EXIT_FAILURE;
 	}
 
+	lockfd = lockdb();
+
 	dir = opendir("var/pkg");
 	if (!dir) {
 		fprintf(stderr, "opendir %s: %s\n", "var/pkg",
@@ -104,6 +107,8 @@ main(int argc, char *argv[])
 
 	closedir(dir);
 
+	unlockdb(lockfd);
+
 	return EXIT_SUCCESS;
 }
 
diff --git a/util.h b/util.h
@@ -6,6 +6,9 @@
 
 extern char *argv0;
 
+int lockdb(void);
+void unlockdb(int);
+
 #undef strlcat
 size_t strlcat(char *, const char *, size_t);
 #undef strlcpy