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nsenter: add a macros to print errors 

Signed-off-by: Andrey Vagin <avagin@openvz.org>
This commit is contained in:
Andrey Vagin 2015-01-06 09:42:21 +03:00 committed by Andrew Vagin
parent 85cd86999f
commit 35ae1c4871
1 changed files with 17 additions and 25 deletions
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42
namespaces/nsenter/nsenter.c
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@ -15,6 +15,8 @@
#include <unistd.h>
#include <getopt.h>
#define pr_perror(fmt, ...) fprintf(stderr, "nsenter: " fmt ": %m\n", ##__VA_ARGS__)
static const kBufSize = 256;
static const char *kNsEnter = "nsenter";
@ -23,8 +25,7 @@ void get_args(int *argc, char ***argv)
// Read argv
int fd = open("/proc/self/cmdline", O_RDONLY);
if (fd < 0) {
fprintf(stderr,
"nsenter: Unable to open /proc/self/cmdline: %m\n");
pr_perror("Unable to open /proc/self/cmdline");
exit(1);
}
@ -40,8 +41,7 @@ void get_args(int *argc, char ***argv)
read(fd, contents + contents_offset,
contents_size - contents_offset);
if (bytes_read < 0) {
fprintf(stderr,
"nsenter: Unable to read from /proc/self/cmdline: %m\n");
pr_perror("Unable to read from /proc/self/cmdline");
exit(1);
}
contents_offset += bytes_read;
@ -101,7 +101,7 @@ void nsenter()
#ifdef PR_SET_CHILD_SUBREAPER
if (prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0) == -1) {
fprintf(stderr, "nsenter: failed to set child subreaper: %m\n");
pr_perror("Failed to set child subreaper");
exit(1);
}
#endif
@ -133,8 +133,7 @@ void nsenter()
init_pid = strtol(init_pid_str, NULL, 10);
if ((init_pid == 0 && errno == EINVAL) || errno == ERANGE) {
fprintf(stderr,
"nsenter: Failed to parse PID from \"%s\" with output \"%d\" and error: %m\n",
pr_perror("Failed to parse PID from \"%s\" with output \"%d\"",
init_pid_str, init_pid);
print_usage();
exit(1);
@ -144,7 +143,7 @@ void nsenter()
argv += 3;
if (setsid() == -1) {
fprintf(stderr, "setsid failed. Error: %m\n");
pr_perror("setsid failed");
exit(1);
}
// before we setns we need to dup the console
@ -152,9 +151,7 @@ void nsenter()
if (console != NULL) {
consolefd = open(console, O_RDWR);
if (consolefd < 0) {
fprintf(stderr,
"nsenter: failed to open console %s: %m\n",
console);
pr_perror("Failed to open console %s", console);
exit(1);
}
}
@ -166,7 +163,7 @@ void nsenter()
int ns_dir_fd;
ns_dir_fd = open(ns_dir, O_RDONLY | O_DIRECTORY);
if (ns_dir_fd < 0) {
fprintf(stderr, "Unable to open %s: %m\n", ns_dir);
pr_perror("Unable to open %s", ns_dir);
exit(1);
}
@ -179,24 +176,20 @@ void nsenter()
if (fstatat(ns_dir_fd, namespaces[i], &st, AT_SYMLINK_NOFOLLOW) == -1) {
if (errno == ENOENT)
continue;
fprintf(stderr,
"nsenter: Failed to stat ns file \"%s\" for ns \"%s\" with error: %m\n",
pr_perror("Failed to stat ns file %s for ns %s",
ns_dir, namespaces[i]);
exit(1);
}
int fd = openat(ns_dir_fd, namespaces[i], O_RDONLY);
if (fd == -1) {
fprintf(stderr,
"nsenter: Failed to open ns file \"%s\" for ns \"%s\" with error: %m\n",
pr_perror("Failed to open ns file %s for ns %s",
ns_dir, namespaces[i]);
exit(1);
}
// Set the namespace.
if (setns(fd, 0) == -1) {
fprintf(stderr,
"nsenter: Failed to setns for \"%s\" with error: %m\n",
namespaces[i]);
pr_perror("Failed to setns for %s", namespaces[i]);
exit(1);
}
close(fd);
@ -206,21 +199,21 @@ void nsenter()
// We must fork to actually enter the PID namespace.
int child = fork();
if (child == -1) {
fprintf(stderr, "nsenter: Unable to fork a process: %m\n");
pr_perror("Unable to fork a process");
exit(1);
}
if (child == 0) {
if (consolefd != -1) {
if (dup2(consolefd, STDIN_FILENO) != 0) {
fprintf(stderr, "nsenter: failed to dup 0: %m\n");
pr_perror("Failed to dup 0");
exit(1);
}
if (dup2(consolefd, STDOUT_FILENO) != STDOUT_FILENO) {
fprintf(stderr, "nsenter: failed to dup 1: %m\n");
pr_perror("Failed to dup 1");
exit(1);
}
if (dup2(consolefd, STDERR_FILENO) != STDERR_FILENO) {
fprintf(stderr, "nsenter: failed to dup 2: %m\n");
pr_perror("Failed to dup 2\n");
exit(1);
}
}
@ -230,8 +223,7 @@ void nsenter()
// Parent, wait for the child.
int status = 0;
if (waitpid(child, &status, 0) == -1) {
fprintf(stderr,
"nsenter: Failed to waitpid with error: %m\n");
pr_perror("nsenter: Failed to waitpid with error");
exit(1);
}
// Forward the child's exit code or re-send its death signal.