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1 /*
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2 * Operating system dependent routines.
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3 *
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4 * Most of the stuff in here is based on Unix, but an attempt
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5 * has been made to make things work on other operating systems.
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6 * This will sometimes result in a loss of functionality, unless
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7 * someone rewrites code specifically for the new operating system.
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8 *
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9 * The makefile provides defines to decide whether various
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10 * Unix features are present.
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11 */
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12
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13 #include <stdio.h>
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14 #include <signal.h>
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15 #include <setjmp.h>
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16 #include "less.h"
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17
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18 /*
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19 * BSD setjmp() saves (and longjmp() restores) the signal mask.
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20 * This costs a system call or two per setjmp(), so if possible we clear the
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21 * signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
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22 * On other systems, setjmp() doesn't affect the signal mask and so
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23 * _setjmp() does not exist; we just use setjmp().
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24 */
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25 #if HAS__SETJMP && SIGSETMASK
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26 #define SET_JUMP _setjmp
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27 #define LONG_JUMP _longjmp
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28 #else
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29 #define SET_JUMP setjmp
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30 #define LONG_JUMP longjmp
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31 #endif
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32
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33 extern char *getenv();
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34
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35 public int reading;
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36
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37 static jmp_buf read_label;
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38
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39 /*
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40 * Like read() system call, but is deliberately interruptible.
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41 * A call to intread() from a signal handler will interrupt
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42 * any pending iread().
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43 */
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44 public int
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45 iread(fd, buf, len)
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46 int fd;
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47 char *buf;
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48 unsigned int len;
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49 {
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50 register int n;
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51
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52 if (SET_JUMP(read_label))
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53 {
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54 /*
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55 * We jumped here from intread.
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56 */
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57 reading = 0;
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58 #if SIGSETMASK
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59 sigsetmask(0);
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60 #endif
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61 return (READ_INTR);
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62 }
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63
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64 flush();
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65 reading = 1;
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66 n = read(fd, buf, len);
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67 reading = 0;
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68 if (n < 0)
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69 return (-1);
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70 return (n);
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71 }
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72
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73 /*
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74 * Interrupt a pending iread().
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75 */
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76 public void
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77 intread()
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78 {
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79 LONG_JUMP(read_label, 1);
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80 }
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81
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82 #if GET_TIME
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83 public long
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84 get_time()
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85 {
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86 long t;
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87
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88 time(&t);
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89 return (t);
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90 }
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91 #endif
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92
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93 /*
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94 * errno_message: Return an error message based on the value of "errno".
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95 */
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96
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97 #if PERROR
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98
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99 extern char *sys_errlist[];
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100 extern int sys_nerr;
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101 extern int errno;
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102
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103 public char *
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104 errno_message(filename)
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105 char *filename;
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106 {
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107 register char *p;
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108 register char *m;
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109 char msg[16];
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110
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111 if (errno < sys_nerr)
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112 p = sys_errlist[errno];
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113 else
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114 {
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115 sprintf(msg, "Error %d", errno);
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116 p = msg;
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117 }
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118 m = (char *) ecalloc(strlen(filename) + strlen(p) + 3, sizeof(char));
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119 sprintf(m, "%s: %s", filename, p);
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120 return (m);
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121 }
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122
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123 #else
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124
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125 public char *
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126 errno_message(filename)
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127 char *filename;
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128 {
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129 register char *m;
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130 static char msg[] = ": cannot open";
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131
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132 m = (char *) ecalloc(strlen(filename) + sizeof(msg), sizeof(char));
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133 strcpy(m, filename);
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134 strcat(m, msg);
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135 return (m);
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136 }
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137
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138 #endif
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