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Diffstat (limited to '')
| -rw-r--r-- | tools/lib/subcmd/exec-cmd.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/tools/lib/subcmd/exec-cmd.c b/tools/lib/subcmd/exec-cmd.c new file mode 100644 index 000000000..33e94fb83 --- /dev/null +++ b/tools/lib/subcmd/exec-cmd.c @@ -0,0 +1,210 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/compiler.h> +#include <linux/string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> +#include <string.h> +#include <stdlib.h> +#include <stdio.h> +#include "subcmd-util.h" +#include "exec-cmd.h" +#include "subcmd-config.h" + +#define MAX_ARGS 32 +#define PATH_MAX 4096 + +static const char *argv_exec_path; +static const char *argv0_path; + +void exec_cmd_init(const char *exec_name, const char *prefix, + const char *exec_path, const char *exec_path_env) +{ + subcmd_config.exec_name = exec_name; + subcmd_config.prefix = prefix; + subcmd_config.exec_path = exec_path; + subcmd_config.exec_path_env = exec_path_env; +} + +#define is_dir_sep(c) ((c) == '/') + +static int is_absolute_path(const char *path) +{ + return path[0] == '/'; +} + +static const char *get_pwd_cwd(void) +{ + static char cwd[PATH_MAX + 1]; + char *pwd; + struct stat cwd_stat, pwd_stat; + if (getcwd(cwd, PATH_MAX) == NULL) + return NULL; + pwd = getenv("PWD"); + if (pwd && strcmp(pwd, cwd)) { + stat(cwd, &cwd_stat); + if (!stat(pwd, &pwd_stat) && + pwd_stat.st_dev == cwd_stat.st_dev && + pwd_stat.st_ino == cwd_stat.st_ino) { + strlcpy(cwd, pwd, PATH_MAX); + } + } + return cwd; +} + +static const char *make_nonrelative_path(const char *path) +{ + static char buf[PATH_MAX + 1]; + + if (is_absolute_path(path)) { + if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) + die("Too long path: %.*s", 60, path); + } else { + const char *cwd = get_pwd_cwd(); + if (!cwd) + die("Cannot determine the current working directory"); + if (snprintf(buf, PATH_MAX, "%s/%s", cwd, path) >= PATH_MAX) + die("Too long path: %.*s", 60, path); + } + return buf; +} + +char *system_path(const char *path) +{ + char *buf = NULL; + + if (is_absolute_path(path)) + return strdup(path); + + astrcatf(&buf, "%s/%s", subcmd_config.prefix, path); + + return buf; +} + +const char *extract_argv0_path(const char *argv0) +{ + const char *slash; + + if (!argv0 || !*argv0) + return NULL; + slash = argv0 + strlen(argv0); + + while (argv0 <= slash && !is_dir_sep(*slash)) + slash--; + + if (slash >= argv0) { + argv0_path = strndup(argv0, slash - argv0); + return argv0_path ? slash + 1 : NULL; + } + + return argv0; +} + +void set_argv_exec_path(const char *exec_path) +{ + argv_exec_path = exec_path; + /* + * Propagate this setting to external programs. + */ + setenv(subcmd_config.exec_path_env, exec_path, 1); +} + + +/* Returns the highest-priority location to look for subprograms. */ +char *get_argv_exec_path(void) +{ + char *env; + + if (argv_exec_path) + return strdup(argv_exec_path); + + env = getenv(subcmd_config.exec_path_env); + if (env && *env) + return strdup(env); + + return system_path(subcmd_config.exec_path); +} + +static void add_path(char **out, const char *path) +{ + if (path && *path) { + if (is_absolute_path(path)) + astrcat(out, path); + else + astrcat(out, make_nonrelative_path(path)); + + astrcat(out, ":"); + } +} + +void setup_path(void) +{ + const char *old_path = getenv("PATH"); + char *new_path = NULL; + char *tmp = get_argv_exec_path(); + + add_path(&new_path, tmp); + add_path(&new_path, argv0_path); + free(tmp); + + if (old_path) + astrcat(&new_path, old_path); + else + astrcat(&new_path, "/usr/local/bin:/usr/bin:/bin"); + + setenv("PATH", new_path, 1); + + free(new_path); +} + +static const char **prepare_exec_cmd(const char **argv) +{ + int argc; + const char **nargv; + + for (argc = 0; argv[argc]; argc++) + ; /* just counting */ + nargv = malloc(sizeof(*nargv) * (argc + 2)); + + nargv[0] = subcmd_config.exec_name; + for (argc = 0; argv[argc]; argc++) + nargv[argc + 1] = argv[argc]; + nargv[argc + 1] = NULL; + return nargv; +} + +int execv_cmd(const char **argv) { + const char **nargv = prepare_exec_cmd(argv); + + /* execvp() can only ever return if it fails */ + execvp(subcmd_config.exec_name, (char **)nargv); + + free(nargv); + return -1; +} + + +int execl_cmd(const char *cmd,...) +{ + int argc; + const char *argv[MAX_ARGS + 1]; + const char *arg; + va_list param; + + va_start(param, cmd); + argv[0] = cmd; + argc = 1; + while (argc < MAX_ARGS) { + arg = argv[argc++] = va_arg(param, char *); + if (!arg) + break; + } + va_end(param); + if (MAX_ARGS <= argc) { + fprintf(stderr, " Error: too many args to run %s\n", cmd); + return -1; + } + + argv[argc] = NULL; + return execv_cmd(argv); +} |